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Leaf water storage is a complex interaction between live tissue properties (anatomy and physiology) and physicochemical properties of biomolecules and water. How leaves adsorb water molecules based on interactions between biomolecules and water, including hydrogen bonding, challenges our understanding of hydraulic acclimation in tall trees where leaves are exposed to more water stress. Here, we used infrared (IR) microspectroscopy with changing relative humidity (RH) on leaves of tall Cryptomeria japonica trees. OH band areas correlating with water content were larger for treetop (52 m) than for lower-crown (19 m) leaves, regardless of relative humidity (RH). This high water adsorption in treetop leaves was not explained by polysaccharides such as Ca-bridged pectin, but could be attributed to the greater cross-sectional area of the transfusion tissue. In both treetop and lower-crown leaves, the band areas of long (free water: around 3550 cm-1) and short (bound water: around 3200 cm-1) hydrogen bonding OH components showed similar increases with increasing RH, while the band area of free water was larger at the treetop leaves regardless of RH. Free water molecules with longer H bonds were considered to be adsorbed loosely to hydrophobic CH surfaces of polysaccharides in the leaf-cross sections.

DOI： 10.3390/plants9091107

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In order to examine the mixing properties of glycerol-water and diglycerol-water solutions, these solutions were measured using attenuated total reflection infrared spectroscopy. The absorbance spectra corrected for 1 mu m thickness were subtracted by pure polyols for obtaining water spectra, and by pure water for polyol spectra. Both asymmetric and symmetric CH2 stretching vibration bands (around 2940, 2885 cm(-1)) shifted about 10 cm(-1) to lower wavenumber side (redshifts) with increasing polyol concentrations, especially at higher concentrations. Redshifts of C-O-H rocking bands (around 1335 cm(-1)) with increasing polyol concentrations are slightly larger for diglycerol-water (10 > 6 cm(-1)) than glycerol-water solutions. C-O stretching bands of CHOH groups (1125 and 1112 cm(-1)) shift slightly but in opposite sides for glycerol and diglycerol at highest polyol concentrations (90-100 wt%). These shifts of CH2 stretching, COH rocking, and CO stretching of CHOH at higher polyol concentrations suggest interactions of outer CH2 with inner CHOH groups of surrounding polyols. The normalized band area changes with polyol concentrations could be fitted by quadratic polynomials possibly due to mixtures of different interactions between water-water, polyol-water, and polyol-polyol molecules. The OH stretching band for diglycerol 90 wt% shows three humps indicating at least three OH components: long, medium, and short H bond water molecules. Short H bond water molecules are the major component possibly between inner CHOH and outer side CH2OH groups, while the long H component might loosely bind to outer CH2OH groups.

DOI： 10.1177/0003702820919530

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Front face fluorescence spectroscopy of typical Japanese soil powders (soil A: Typic Hapludand; soil H: Typic Hydraquent; soil Y: Typic Paleudult) has been conducted. Three dimensional excitation-emission matrix fluorescence spectra of the 100 wt% soils showed similar fluorescence patterns to each other. The fluorescence patterns were similar between the soil samples and their residues after extraction by NaOH solution for 60 min. In order to examine fluorescence extinction from a view point of whiteness of the soils, the soil powders were mixed with white and black diluents (Al2O3 and Fe3O4) and fluorescence spectra of the mixtures were measured at 450 nm excitation. At low levels of dilution with Al2O3 (2-100 wt% of A: 50-100 wt% of H and Y), the fluorescence intensities increased with dilution. At high levels of dilution with Al2O3, the fluorescence intensities decreased with dilution. On the other hand, fluorescent intensities decreased by dilution with Fe3O4. These results suggested inner filter effect-like fluorescence extinction by (1) large amount of blackish organic compounds giving high total carbon value and (2) blackish non-fluorescent mineral compounds. In order to correct the fluorescence intensities of the mixtures containing the sample soils and the diluents, we preliminary applied a correction method based on the Kubelka-Munk theory using diffuse reflectance. The corrected fluorescence intensities of samples with white diluents (Al2O3) were described by a simple fluorescence response model having saturation values. (C) 2020 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.saa.2020.118188

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Adsorption of water to a phospholipid (lecithin) and a ceramide were studied by IR microspectroscopy equipped with a humidity control system and quartz crystal microbalance (QCM). The water weight ratios increase up to 12.2 wt% for lecithin and 1.2 wt% for ceramide at RH similar to 80%, with linear correlations with infrared OH (+NH) band areas. For lecithin, the 1230 cm(-1) band (PO2-) and the 1735 cm(-1) band (C=O) shift to lower wavenumbers, while the 1060 cm(-1) band (PO2-, P-O-C) shift to higher wavenumber with RH. Band areas of phosphates (1230 and 1060 cm(-1)) increase with RH showing positive relations with the band area of bound water. Bound water molecules with shorter H bonds might be bound to these phosphate groups. Band areas of aliphatic CHs are negatively correlated with the increasing adsorption of free water. Free water molecules with longer H bonds might interact loosely with aliphatic chains of lecithin. For ceramide, only the 1045 cm-1 band (C-O) shows a small red shift at higher RHs than 60%, indicating adsorption of bound water to C-O bonds. Amounts of water molecules adsorbed to ceramide are very limited due to few adsorption of free water. (c) 2019 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.saa.2019.117779

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Combined microspectroscopic mapping have been conducted on a red-colored Tenzan granite sample by using an original visible-fluorescence-Raman microspectrometer together with a low vacuum scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) without coating. Visible darkfield reflectance spectra were converted to L*a*b* color values and Kubelka-Munk (KM) spectra. Large a* value (red) positions correspond to large band areas at 500-560 nm, possibly due to hematite-like iron oxide, while large b* value (yellow) positions to large band areas at 450-500 nm, due to epidote-like mineral. Scanning electron microscopy-energy dispersive spectrometry analyses indicated that the reddish parts are Na and K-feldspars with low Fe contents (<0.5 wt%). Raman microspectroscopy could not detect hematite-like minerals. Since some hematite-like minerals were only identified by transmission electron microscope, they are considered to be submicron microcrystals disseminated in feldspar matrices. The KM spectra for prehnite-like minerals show a weak broad band around 430 nm due possibly to a ligand field band of Fe3+ without clear Fe2+-Fe3+ inter-valence charge transfer (IVCT) bands around 720 nm. Therefore, Fe in prehnite is not considered to be present as hematite-like iron oxide, but can be mainly present as Fe3+ replacing Al3+ in the crystal structure. Since determination of physicochemical states of Fe such as valence and coordination states (Fe2+ or Fe3+, oxide or in crystal lattice, etc.) and their distributions are extremely difficult, especially in complex colored materials such as rocks, the combined microspectroscopic methods are useful for their nondestructive characterization.

DOI： 10.1177/0003702818823555

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Background Natures and amounts of water retained at the surface of stratum corneum (SC) of human skins, affecting skin health and penetration of chemical components, remain unclear. Methods A keratin film, a main component of human SC surface, was measured by IR micro-spectroscopy combined with a quartz crystal microbalance (QCM) and a relative humidity (RH) control system. Results Water contents increased with RH up to about 19 wt% and were correlated linearly with the OH + NH band areas in IR spectra of the keratin film. The OH + NH band areas for the triple helix collagen film are about twice as large as those for the keratin film (double helix). The free water component increases with RH by keeping the bound water component minor for the keratin film. About twice of water retention capacity of the collagen film can be due to increasing adsorption of free water, interacting possibly with hydrophobic aliphatic CH surfaces. Conclusion The present results suggest relatively low water contents less than about 19 wt% of outermost SC layers of human skin composed mostly of keratin exposed to ambient RH conditions. The triple helix collagen can be used as an effective moisturizing agent.

DOI： 10.1111/srt.12641

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Hydrothermal decolorization (color loss) of Nordic fulvic and humic acid solutions at 80-180 degrees C for 0-600 hours was traced by ultraviolet-visible (UV-Vis) spectroscopy. These changes were considered to be due to degradation of humic-like chemical structure and represented by decreases in absorbance at 254 nm (UV254). The temperature dependence of their apparent rate constants obtained by the first order reaction model was well described by the Arrhenius equation giving activation energies of 87.6 and 101 kJ mol(-1) for degradation of fulvic and humic acids, respectively. The degradation rates of humic substances were slower than the formation rates of humic-like substances by the Maillard-type browning reaction, suggesting that humic-like substances can be preserved in the aquatic environments, where their formation (browning) and degradation (decolorization) processes are occurring together. By extrapolation to 15 degrees C of the Arrhenius equation, 99-1980 years of time scales for these processes were estimated. A time scale of changes in UV254 in natural aquatic environments estimated by kinetic analyses on Ago Bay bottom sediments (18 years) were closer to the formation time scales of humic-like substances.

DOI： 10.2343/geochemj.2.0575

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Language：Japanese   Publisher：The Geological Society of Japan  

DOI： 10.14863/geosocabst.2019.0_467

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In 2001, the first author (S.N.) led the publication of a book entitled "Geochemistry and the origin of life" in collaboration with Dr. Andre Brack aiming to figure out geo- and astro-chemical processes essential for the emergence of life. Since then, a great number of research progress has been achieved in the relevant topics from our group and others, ranging from the extraterrestrial inputs of life's building blocks, the chemical evolution on Earth with the aid of mineral catalysts, to the fossilized records of ancient microorganisms. Here, in addition to summarizing these findings for the origin and early evolution of life, we propose a new hypothesis for the generation and co-evolution of photosynthesis with the redox and photochemical conditions on the Earth's surface. Besides these bottom-up approaches, we introduce an experimental study on the role of water molecules in the life's function, focusing on the transition from live, dormant, and dead states through dehydration/hydration. Further spectroscopic studies on the hydrogen bonding behaviors of water molecules in living cells will provide important clues to solve the complex nature of life.

DOI： 10.3390/life8040039

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Infrared (IR) spectral changes with time of biogenic and inorganic silica have been examined using in situ IR micro-spectroscopy by using an original hydrothermal diamond cell. Centric diatoms (diameters = 100-350 mu m) and silica gels (C-300, Wako Chemicals) were heated at 125-185 degrees C range with a pressure of 3 MPa. Decreases of 950 cm(-1) (Si-OH) peak heights could be fitted by a combination of exponential and linear decreases (y = A(1) exp (-k(1)t)-k(0) t+A(0)). The first-order rate constants k(1) [s(-1)] for Si-OH decreases of diatoms and silica gels are similar but the activation energy was lower for diatoms (61 kJ.mol(-1) < 106 kJ.mol(-1)). The first-order rate constants k(1) [s(-1)] for Si-OH decreases of diatoms and silica gels are much faster than reported hydrothermal transformation rates of silica (Opal A to Opal CT and Opal CT to quartz). These results indicate that the exponential Si-OH decreases observed in biogenic and inorganic silica during hydrothermal reactions are considered to correspond to dehydration-condensation reactions in the amorphous states (Si-OH+HO-Si -> Si-O-Si). In fact, band area ratios 1220 cm(-1)/1120 cm(-1) increased exponentially indicating more bridging of Si-O-Si. On the other hand, the linear decreases of Si-OH of silica gels (k(0) [s(-1)]) were considered to be due to dissolution of silica. By using the grain size and density of silica gels, the zero-order dissolution rate constants k(0)* [mol.m(-2).s(-1)] were calculated from k(0) [s(-1)]. The obtained dissolution rates k(0)* are larger than reported values for silica glass and quartz. The zero-order dissolution rates k(0) [s(-1)] for diatoms are similar to those for silica gels but with a lower activation energy (32 kJ.mol(-1) < 60 kJ.mol(-1)). The smaller activation energy values for diatoms than silica gels both for the first and zero-order decrease rates of Si-OH might indicate catalytic effects of organic components bound to biogenic silica for the dehydration-condensation reaction and dissolution. The present in situ hydrothermal IR micro-spectroscopy is useful for characterizing transformation of amorphous materials including inorganic-organic composites.

DOI： 10.1177/0003702818771817

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Progress of the simulated Maillard reaction for 0.1 mol L-1 glycine and ribose mixture solution at 80 degrees C for 0-7 days forming humic-like substances in the presence/absence of goethite was examined by ultraviolet-visible (UV-VIS) spectroscopy. 254 nm and 420 nm absorption intensities for the product solutions with goethite increased faster than for those without goethite, indicating enhancement of the reaction progress in the presence of goethite in several days at 80 degrees C. Adsorption onto goethite of reactants of the reaction were directly monitored by attenuated total reflection infrared (ATR-IR) spectroscopy with thin layers of goethite on the ATR crystal (ZnSe). IR spectral changes with time for the reactant solution (0.1 mol L-1 glycine and ribose mixture solution) on the goethite layer suggested fast adsorption within a few hours at room temperature of oxygenated components of glycine onto positively charged goethite surface. In situ heating ATR-IR kinetic measurements of humic-goethite interfaces will be useful for examining mechanisms of surface processes leading to reaction enhancement.

DOI： 10.1380/ejssnt.2018.411

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

To examine differences of water-retention mechanisms between pectins with and without Ca2+, quartz crystal microbalance (QCM) and infrared microspectroscopy combined with a humidity-control system were used to analyze differences in amounts and species of adsorbed water to pectins without and with Ca2+. QCM analysis shows that water contents are similar to 2-3 times larger for the pectin film with Ca2+ than that without Ca2+. The difference IR spectra suggest that long, medium, and short H-bond water molecules (free, medium, and bound water) are adsorbed to the pectin film without Ca2+. IR peak shifts of C=O of COOH and C-OH suggest that these water molecules are hydrogen-bonded to C=O and C-OH groups. In addition to these water molecules, bulk water is adsorbed. IR OH band areas fitted by four Gaussian components show that bulk water is mainly adsorbed to the pectin film with Ca2+, possibly among skeletal chains of pectin bridged by Ca2+.

DOI： 10.1021/acs.jafc.8b02413

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The formation processes of humic-like substances have been simulated by heating a glycine and ribose mixed solution (0.1 molL(-1)) at 80 degrees C using the Maillard reaction. Ultraviolet-visible (UV-Vis), three-dimensional excitation emission spectroscopy and size exclusion liquid chromatography succeeded in quantitatively tracing increases of the products during the heating of glycine and ribose mixed solution (0.1 molL(-1)). Two-dimensional correlation spectroscopic analyses suggested that a band area around 280 nm (UV280) and 254 nm absorbance (UV254) can be used as measures of the formation of furfural-like intermediates and humic-like products, respectively. They were monitored using in situ UV-Vis spectroscopy with the original heatable liquid cell at 60-80 degrees C. Kinetic analyses of the obtained data gave activation energies of 91.4-96.6 kJ mol(-1). These nondestructive measurements by an in situ spectroscopic method did not require any additional procedures including drying or extracting the solution and they can be effectively used for direct tracing of the reaction progress and/or decomposition.

DOI： 10.1177/0003702818775737

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Electrical conductivity of silica nanoparticles deposited on electrodes from colloidal suspension were measured under controlled relative humidity (RH). The electrical conductivity values at 1 kHz increased with increasing RH. Amounts of water adsorbed on silica nanoparticles were measured by quartz crystal microbalance (QCM) and they also increased with increasing RH. An empirical power law relation was observed between the reported surface conductivity and RH data for a silica glass. By applying this relation to the silica nanoparticles, the water film thicknesses are estimated to be from 0.08 nm to 0.23 nm. The corresponding specific surface area (SSA) becomes smaller (102 m(2) g(-1)) than the reported value (215 m(2) g(-1)), indicating aggregation of the nanoparticles. In fact, aggregated rod-like structures were observed under electron and laser scanning microscopy. The electrical conduction of deposited silica nanoparticles under various RH can be understood by surface conduction in thin water films adsorbed on the nanoparticles.

DOI： 10.1380/ejssnt.2018.376

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

Aliphatic C-H bonds are one of the major organic signatures detected in Proterozoic organic microfossils, and their origin is a topic of interest. To investigate the influence of the presence of silica on the thermal alteration of aliphatic C-H bonds in prokaryotic cells during diagenesis, cyanobacteria Synechocystis sp. PCC6803 were heated at temperatures of 250-450 degrees C. Changes in the infrared (IR) signals were monitored by micro-Fourier transform infrared (FTIR) spectroscopy. Micro-FTIR shows that absorbances at 2,925cm(-1) band (aliphatic CH2) and 2,960cm(-1) band (aliphatic CH3) decrease during heating, indicating loss of the C-H bonds, which was delayed by the presence of silica. A theoretical approach using solid-state kinetics indicates that the most probable process for the aliphatic C-H decrease is three-dimensional diffusion of alteration products under both non-embedded and silica-embedded conditions. The extrapolation of the experimental results obtained at 250-450 degrees C to lower temperatures implies that the rate constant for CH3 (k(CH3)) is similar to or lower than that for CH2 (k(CH2); i.e., CH3 decreases at a similar rate or more slowly than CH2). The peak height ratio of 2,960cm(-1) band (CH3)/2,925cm(-1) band (CH2; R-3/2 values) either increased or remained constant during the heating. These results reveal that the presence of silica does affect the decreasing rate of the aliphatic C-H bonds in cyanobacteria during thermal maturation, but that it does not significantly decrease the R-3/2 values. Meanwhile, studies of microfossils suggest that the R-3/2 values of Proterozoic prokaryotic fossils from the Bitter Springs Group and Gunflint Formation have decreased during fossilization, which is inconsistent with the prediction from our experimental results that R-3/2 values did not decrease after silicification. Some process other than thermal degradation, possibly preservation of specific classes of biomolecules with low R-3/2 values, might have occurred during fossilization.

DOI： 10.1111/gbi.12294

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

Hydration/dehydration processes of dry yeast cells have been monitored by infrared micro-spectroscopy under controlled relative humidity and temperature. Changes in IR absorption bands of water, amides (proteins) and lipids were analyzed during increasing/decreasing RH at 35 degrees C and during heating at 60 degrees C. While water and protein followed RH conditions at 35 degrees C, they show exponential decreases with similar rate constants at 60 degrees C.

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Recent studies in the tallest tree species suggest that physiological and anatomical traits of tree-top leaves are adapted to water-limited conditions. In order to examine water retention mechanism of leaves in a tall tree, infrared (IR) micro-spectroscopy was conducted on mature leaf cross-sections of tall Cryptomeria japonica D. Don from four different heights (51, 43, 31 and 19 m). We measured IR transmission spectra and mainly analyzed OH (3700-3000 cm(-1)) and C-O (1190-845 cm(-1)) absorption bands, indicating water molecules and sugar groups, respectively. The changes in IR spectra of leaf sections from different heights were compared with bulk-leaf hydraulics. Both average OH band area of the leaf sections and leaf water content were larger in the upper-crown, while osmotic potential at saturation did not vary with height, suggesting higher dissolved sugar contents of upper-crown leaves. As cell-wall is the main cellular structure of leaves, we inferred that larger average C-O band area of upper-crown leaves reflected higher content of structural polysaccharides such as cellulose, hemicellulose and pectin. Infrared micro-spectroscopic imaging showed that the OH and C-O band areas are large in the vascular bundle, transfusion tissue and epidermis. Infrared spectra of individual tissue showed that much more water is retained in vascular bundle and transfusion tissue than mesophyll. These results demonstrate that IR micro-spectroscopy is a powerful tool for visualizing detailed, quantitative information on the spatial distribution of chemical substances within plant tissues, which cannot be done using conventional methods like histochemical staining. The OH band could be well reproduced by four Gaussian OH components around 3530 (free water: long H bond), 3410 (pectin-like OH species), 3310 (cellulose-like OH species) and 3210 (bound water: short H bond) cm(-1), and all of these OH components were higher in the upper crown while their relative proportions did not vary with height. Based on the spectral analyses, we inferred that polysaccharides play a key role in biomolecular retention of water in leaves of tall C. japonica.

DOI： 10.1093/treephys/tpx085

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SAGE PUBLICATIONS INC  

Infrared (IR) microspectroscopy combined with a quartz crystal microbalance (QCM) together with an original relative humidity (RH) control system has been developed for studying water adsorption on a collagen film. The adsorbed water weights measured by QCM are almost similar for wetting and drying processes at 28 degrees C, indicating that the collagen film is close to the water adsorption/desorption equilibria. A broad OH+NH stretching band area (3000-3700 cm(-1)) in the IR spectra of the collagen film increased linearly with the adsorbed weight until about 1.2 mu g/8.0 mu g dry collagen film at relative humidity (RH) = 40%, while at higher RH (60%, 80%), the band area deviates from the linear trend to the lower side, due to viscoelasticity and others. The OH+NH band can be simulated by four Gaussian components at 3440, 3330, 3210, and 3070 cm(-1) with the relatively constant band areas of 3330 and 3070 cm(-1) components due to amide A and B (NH) for increasing and decreasing RH. Bound water (3210 cm(-1) component: short H bond) constitutes around 70% of total water (3440+3210 cm(-1) band areas) at RH = 4.9% but decreases to 23% at RH = 80.3%, where free water (3440 cm(-1) component: long H bond) becomes dominant over 70%. The peak shifts of C=O stretching (Amide I) and N-H bending (Amide II) can be understood by increasing hydrogen bonding of water molecules (bound water) bound to peptides at lower RH. The higher wavenumber shifts of CH stretching can be due to the loose binding of water molecules (free water) to aliphatic chains on the collagen surface, especially at higher RH. The present combined QCM-IR method is useful for studying amounts and natures of water adsorbing on biomolecules.

DOI： 10.1177/0003702817693855

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

It has long been suggested that mineral surfaces played an important role in peptide bond formation on the primitive Earth. However, it remains unclear which mineral species was key to the prebiotic processes. This is because great discrepancies exist among the reported catalytic efficiencies of minerals for amino acid polymerizations, owing to mutually different experimental conditions. This study examined polymerization of glycine (Gly) on nine oxide minerals (amorphous silica, quartz, alpha-alumina and gamma-alumina, anatase, rutile, hematite, magnetite, and forsterite) using identical preparation, heating, and analytical procedures. Results showed that a rutile surface is the most effective site for Gly polymerization in terms of both amounts and lengths of Gly polymers synthesized. The catalytic efficiency decreased as rutile > anatase > gamma-alumina > forsterite > alpha- alumina > magnetite > hematite > quartz > amorphous silica. Based on reported molecular-level information for adsorption of Gly on these minerals, polymerization activation was inferred to have arisen from deprotonation of the NH3 (+) group of adsorbed Gly to the nucleophilic NH2 group, and from withdrawal of electron density from the carboxyl carbon to the surface metal ions. The orientation of adsorbed Gly on minerals is also a factor influencing the Gly reactivity. The examination of Gly-mineral interactions under identical experimental conditions has enabled the direct comparison of various minerals' catalytic efficiencies and has made discussion of polymerization mechanisms and their relative influences possible Further systematic investigations using the approach reported herein (which are expected to be fruitful) combined with future microscopic surface analyses will elucidate the role of minerals in the process of abiotic peptide bond formation.

DOI： 10.1007/s11084-016-9516-z

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Language：Japanese   Publisher：GEOCHEMICAL SOCIETY OF JAPAN  

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DOI： 10.14862/geochemproc.64.0_79

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© The Authors 2017. Electrical conductance G at 100 kHz of Berea sandstone initially saturated with varying NaCl concentrations was measured by an impedance meter at decreasing water saturation. The obtained conductance G values can be well simulated by the model equation composed of conductance of bulk pore water and that of mineral surfaces by introducing both tortuosities of bulk pore water τb and mineral surfaces τs. The surface conductivity s = 2.1 × 10−10 S and the tortuosity of mineral surfaces τs = 2.6 in this equation can be valid for most of the data at varying water saturation except for the lowest water saturation (Sw = 0.05). The tortuosity of pore water τb increased from 1.7 at Sw = 1.0 to 15 at Sw = 0.05 with a power law relationship. The present electrical conduction model with double tortuosities of bulk pore water τb and mineral surfaces τs can be considered as an alternative expression of the combined Archie’s first and second laws in terms of tortuosities and would be useful for describing conductance of electrolyte containing partially saturated rocks including very low water saturation.

DOI： 10.1093/gji/ggx092

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DOI： 10.14862/geochemproc.64.0_255

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DOI： 10.14862/geochemproc.64.0_276

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

The Maillard reaction is one of the dominant processes forming humic substances in natural waters affecting environmental pollution. In this study, we succeeded in quantitatively following decreases of starting materials (glycine and ribose) of the Maillard reaction by in situ infrared (IR) transmission spectroscopic observations with an original heatable liquid cell. The obtained kinetic parameters extrapolated to a typical Earth's surface aquatic environments (15 degrees C) indicate the half-life of around 2 years for the decrease of these components as the first step for the formation of humic substances.

DOI： 10.1246/cl.160596

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In situ heating IR microspectroscopy at 260-300 degrees C under air and N-2 conditions has been conducted on diatom frustules to examine aliphatic CH losses during heating, simulating their changes with burial-diagenesis. Assuming a reaction model made up of two first-order kinetic relations, reaction rate constants k(1) and k(2) and activation energies (E-a) were evaluated for aliphatic CHs. The rate constants for loss of aliphatic CHs of diatom frustules under air and N-2 flow are much larger, with much smaller activation energies (57-109 kJ/mol: air; 14-44 kJ/mol: N-2), than those for conventional hydrocarbon generation reactions from kerogens (170-370 kJ/mol) studied at higher temperatures (350-450 degrees C). The CH decrease rates are somewhat different from the amide I decrease (protein degradation) rates. The obtained results suggest that organic transformation reactions including degradation of aliphatic CHs inside the diatom silica frustules might be quite different from those of kerogens separated from the biological structures.

DOI： 10.1002/2016GL068638

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In order to characterize a representative natural bionanomaterial, present day centric diatom samples (diameter, 175-310 mu m) have been analyzed and imaged by infrared (IR) micro-spectroscopy and scanning electron microscopy (SEM). Because diatom silica frustules have complex microscopic morphology, including many void areas such as micro- or nano-pores, the effects of voids on the spectral band shapes were first evaluated. With increasing void area percentage, 1220cm(-1)/1070cm(-1) peak height ratio (Si-O polymerization index) increases and 950cm(-1)/800cm(-1) peak height ratio (Si-OH/Si-O-Si) decreases, both approaching 1. Based on the void area percentage of representative diatom samples determined using SEM image analyses (51.5% to 20.5%) and spectral simulation, the 1220cm(-1)/1070cm(-1) ratios of diatom samples are sometimes affected by the void effect, but the 950cm(-1)/800cm(-1) ratios can indicate real structural information of silica. This void effect should be carefully evaluated for IR micro-spectroscopy of micro-nano-porous materials. Maturity of diatom specimens may be evaluated from: (1) void area percentages determined by SEM; (2) average thicknesses determined by optical microscope; and (3) average values of 1220cm(-1)/1070cm(-1) peak height ratios (opposite trend to the void effect) determined by IR micro-spectroscopy. Microscopic heterogeneities of chemical structures of silica were obtained by IR micro-spectroscopic mapping of four representative diatoms. The 950cm(-1)/800cm(-1) ratios show that large regions of some diatoms consist of hydrated amorphous immature silica. The successful analysis of diatoms by IR micro-spectroscopic data with careful void effect evaluation may be applied to physicochemical structures of many other bionanomaterials.

DOI： 10.1177/0003702815626665

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Interfacial water among silica particles were measured on silica colloid suspensions (0-31.1 vol.%) by transmission infrared micro-spectroscopy. The difference absorption index k spectra from the pure water of silica colloid suspensions with varying volume fractions have residual components in the O-H stretching region: the 3060 cm(-1) component increased linearly with the silica volume fraction, while the 3620 cm(-1) component increased and the 3380 cm(-1) component decreased with much less linearity. The 3060 and 3620 cm(-1) components are considered to be characteristic to the surface silanol and interfacial water and affected by overlapping diffuse electrical double layers among silica particles.

DOI： 10.1380/ejssnt.2015.301

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC APPLIED SPECTROSCOPY  

A method was developed to obtain the absorption coefficient spectrum of a grain of coal (as small as 10(-7)) in the region of aliphatic and aromatic C-H stretching bands (2700-3200 cm(-1)) using infrared transflection microspectroscopy. In this method, the complex refractive index n - ik was determined using an optimization algorithm with the Kramers-Kronig transform so that the calculated transflection spectrum from the Fresnel equation corresponded to the measured one. The obtained absorption coefficients were compared with the bulk values determined from the potassium bromide (KBr) pellet measurement method.

DOI： 10.1366/13-07063

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC APPLIED SPECTROSCOPY  

Visible darkfield reflectance spectroscopy equipped with a color mapping system has been developed and applied to a brown-colored Rokko granite sample. Sample reflectance spectra converted to Kubelka-Munk (KM) spectra show similar features to goethite and lepidocrocite. Raman microspectroscopy on the granite sample surface confirms the presence of these minerals. Here, L"a*b* color values (second Commission Internationale d'Eclairage [CIELab] 1976 color space) were determined from the sample reflection spectra. Grey, yellow, and brown zones of the granite show different L*, a*, and b* values. In the a*-b* diagram, a" and b*values in the grey and brown zones are on the lepidocrocite/ferrihydrite trends, but their values in the brown zone are larger than those in the grey zone. The yellow zone shows data points close to the goethite trend. Iron (hydr)oxide-rich areas can be visualized by means of large a* and b* values in the L*, a*, and b* maps. Although the present method has some problems and limitations, the visible darkfield reflectance spectroscopy can be a useful method for colored-material characterization.

DOI： 10.1366/13-07255

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER/PLENUM PUBLISHERS  

The effects of various cations (Li+, Na+, K+, Rb+, Cs+, Mg2+, Ca2+, Sr2+, Ba2+, Mn2+, Co2+, and Ni2+) and anions (Cl-, Br-, I-, , , , and ) on the molar absorptivity of water in the OH stretching band region (2,600-3,800 cm(-1)) were ascertained from attenuated total reflection infrared spectra of aqueous electrolyte solutions (22 in all). The OH stretching band mainly changes linearly with ion concentrations up to 2 mol center dot L-1, but several specific combinations of cations and anions (Cs2SO4, Li2SO4, and MgSO4) present different trends. That deviation is attributed to ion pair formation and cooperativity in ion hydration, which indicates that the extent of the ion-water interaction reflected by the OH stretching band of water is beyond the first solvation shell of water molecules directly surrounding the ion. The obtained dataset was then correlated with several quantitative parameters representing structural and dynamic properties of water molecules around ions: Delta G (HB), the structural entropy (S (str)), the viscosity B-coefficient (B (eta) ), and the ionic B-coefficient of NMR relaxation (B (NMR)). Results show that modification of the OH stretching band of water caused by ions has quasi-linear relations with all of these parameters. Vibrational spectroscopy can be a useful means for evaluating ion-water interaction in aqueous solutions.

DOI： 10.1007/s10953-014-0193-0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER  

Phosphatized microfossils from ca. 580 Ma from the Doushantuo Formation in the Weng'an region of South China were analyzed by Fourier transform infrared (FOR) microspectroscopy for their chemical characterization. Two morpho-types of phosphatized embryo-like fossils (Megasphaera and Megaclonophycus) were analyzed, together with algal fossils. Transmission IR spectra of the microfossils have absorption bands of around 2960 cm(-1) and 2925 cm(-1), indicating the presence of aliphatic hydrocarbon (anti-symmetric aliphatic CH3 and aliphatic CH2), and have an additional band of around 1595 cm(-1), probably derived from aromatic moieties (aromatic C=C). In addition, IR microscopic mapping shows that aliphatic hydrocarbon and aromatics are distributed inside the embryo-like fossils. The embryo-like fossils appear to show three types of CH3/CH2 peak height ratios (R-3/2) and aromatic C=C/CH2 peak height ratios (R-C=C/2 values): (1) high-R-3/2/low-R-C=C/2 type (R-3/2 = similar to 02-1.0 and R-C=C/2 similar to 0-2), (2) low-R-3/2/medium-R-C=C/2 type (R-3/2 = similar to 0.2-0.6 and R-C=C/2 = similar to 1-4); and (3) low-R-3/2/high-R-C=C/2 type (R-3/2 = similar to 02-0.6 and R-C=C/2 similar to 1-8). All three types are contained in both Megasphaera and Megaclonophycus. Raman spectra for the carbonaceous matter within the rock sample show a similar degree of thermal alteration, indicating that the organics were embedded in situ prior to thermal maturation. The IR spectroscopic differences might reflect differences in original organic compositions of microorganisms, and/or immediate post-mortem alteration. This suggests that the origins of phosphatized embryo-like fossils are more diverse than was previously recognized on the basis of their morphology. A comparison of R-3/2 and R-C=C/2 values in the embryo-like fossils with those of the algal fossils and the extant microorganisms indicates the possible interpretation that some of the embryo-like fossils belong to animal embryo, others are algae, but none of them originate from bacteria. (C) 2013 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

DOI： 10.1016/j.gr.2013.05.002

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© 2014 by Japanese Committee for Rock Mechanics. Spectro-colorimtery and near infrared (NIR) spectroscopy has been applied to rocks for evaluating non-destructively their compressive strength. b∗ values (yellow) of Paleogene granite core samples showed a good correlation with the uniaxial compressive strength (UCS) (156-97 N/mm2), while those for Ryoke granodiorite core samples with less strength (71-0.2 N/mm2) showed only slight changes. NIR band areas around 1450 nm (OH) and 1950 nm (H2O) indicated two different quasi-linear relations in logarithmic diagrams against the UCS. Hydration of feldspars in these granitic rocks is considered to be a good indicator of rock strength. Colors and water contents by these spectroscopic methods showed also positive relations with UCS estimated by the point load test on granodiorite porphyry, welded tuff and sandstones samples. A handy portable spectro-colorimeter (PRISMO MIRAGE) has been developped for measuring visible reflection spectra and color values of materials on field sites. We applied this method for the measurements of colors (L∗: White-black, a∗: Red-green, b∗: yellow-blue) of rock masses at highway construction sites. These color values were compared with the uniaxial compressive strength of rocks estimated from on-site Schmidt Rock Hammer test. The results on igneous rocks (welded tuff and granodiorite porphyry) at HigashiKyushu highway construction sites at Miyazaki, Japan indicated fairly good relationships among a∗ (red) and b∗ (yellow) with the rock strength. However, colors of sandstones at ShinMeishin highway construction sites at Osaka, Japan showed worse correlations with the rock strength and other evaluations such as water contents on-site by handy NIR spectrometer is necessary. The rock quality and its degradation can be evaluated at least partly by this on-site spectroscopy.

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© 2014 by Japanese Committee for Rock Mechanics. Cement grouting of rock fractures will be used to improve mechanical stability and reduce the groundwater inflow of underground construction sites such as high level radioactive waste (HLW) repository. Cementitous grouts will produce a high pH groundwater leading to the dissolution of primary minerals and the precipitation of secondary minerals such as calcium silicate hydrates (C-S-Hs). A new method using infrared (IR) spectroscopy was proposed here for chacraterizing formation processes of C-S-Hs during the simulated alkaline alteration experiments of granitic rocks. Conventional batch experiments were first conducted at 140 ° C with granite and SiO2 powders and Ca(OH)2 solutions. IR spectra on the experimental products showed rapid increases of absorbance around 965 cm-1 due to CSHs within 2 days at 140 °C. An in situ hydrothermal cell with a titanium cell and diamond windows, resistant to high-temperature, high-pressure and high-alkali conditions, was then constructed. This cell was combined with a microscopic Fourier transform infrared (FT-IR) spectrometer and the change in IR spectra with the reaction progress was measured sequentially with a short time interval (5 minutes). In the experiment, quartz, Ca(OH)2 powders (grains of 5-10 μm and 2-3 μm diameter), and water were placed in the cell and heated at temperatures of 100, 110, 120, 130 and 140°C and at a pressure of 3 MPa, and IR spectrum was measured at every 5 minutes. A peak around 790 cm1 due to Si-O-Si of quartz decreased gradually, while another peak around 970 cm1 due to Si-OH of C-S-H increased gradually within about 1000 minutes at 140oC. It was found that formed C-S-Hs did not consist of a single phase because the ratio of peak height at 910 cm1 to that at 970 cm1 changed with time. Temporal changes in each peak height were analyzed assuming that two types of C-S-Hs were formed, and temporal changes in peak at 970 cm1 for each phase were obtained. The obtained results can be used to evaluate formation rates of different C-S-H phases possibly with different Ca/Si ratios.

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© 2014 by Japanese Committee for Rock Mechanics. In order to evaluate degradation rates of rocks, color changes of Oya tuff samples were monitored by a spectro-colorimeter at room temperature (24-25 °C) with relative humidity around 30%. Under ambient condition permitting drying of the rock, water was lost gradually during 8 days. a∗ (green) and b∗ (yellow) values increased rapidly with the increase of L∗ (lightness) value during the first 3 days. On the other hand, b∗ value increased exponentially after 6 days until 42 days. Under wet condition avoiding drying of the rock, L∗, a∗ and b∗ values increased slowly quasi-linearly with time during 130 days. b∗ value increased exponentially for the first 10 days. The first order rate constants for b∗ increases under these ambient and wet conditions are in the order of 1 × 10-6 s-1. These color change rates can be possibly related to oxidation of Fe2+ to Fe3+, occurring at the interface of mineral with water film present under normal humidity conditions.

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Language：Japanese   Publisher：GEOCHEMICAL SOCIETY OF JAPAN  

Coal consists of microscopic organic structural units called macerals together with minerals. Each maceral is not only originated from the different structures of plants, but also experienced different biological and thermal processes. Therefore, chemical characteristics of maceral has a lot of information about origin and reactivity of coal. In this study, chemical functional groups of each maceral is studied using attenuated total reflection infrared micro-spectroscopy (µATR-IR) imaging. Images of chemical functional groups in coal are obtained with a higher spatial resolution (<10µm) than conventional methods.

DOI： 10.14862/geochemproc.61.0_97

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER  

In order to study water resistance of cerium phosphate (CeP) glasses, behavior of infrared (IR) bands of the CeP glass was investigated by using high temperature IR microspectroscopy. A small sharp 2165 cm(-1) band is observed in both Raman and IR spectra only for the phosphate glass containing Ce and is considered to be due to combination of symmetric stretching vibration of P-O (1185 cm(-1)) and asymmetric stretching vibration of P-OH (980 cm(-1)) bonds of Q(2) species, based mainly on the similarity of reversible heating behavior of the IR bands. The 3085 cm(-1) band can correspond to OH stretching vibrations of P-OH species associated with Q(2) species. The broad band around 3500 cm(-1) appeared after the water treatment of the CeP glass. This band can be due to H2O molecules H bonded to P-OH species of the Q(2) units and was mostly lost upon heating. Origins of water resistant properties of the CeP glass were therefore considered to be due to strong Q(2) P-O chains with P-OH bonds. (C) 2013 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jnoncrysol.2013.06.016

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Sulfate, a major anion in nature, can affect the mobility of coexisting dissolved toxic trace elements by influencing the adsorption properties of the species on mineral surfaces. Ferrihydrite is an important scavenger for trace elements in natural water because of its adsorption capacity and its ubiquitous formation in surface conditions. To elucidate the adsorption behavior of the trace elements in natural water, it is important to construct a predictive model of sulfate adsorption on ferrihydrite that can predict the adsorption behavior of sulfate quantitatively under widely various environmental conditions based on the spectroscopic information of sulfate adsorption.In situ infrared spectra for sulfate adsorption on ferrihydrite as a function of pH (3-7), ionic strength (I = 0.01 and 0.1) and sulfate loading ([SO42-] = 0.1 and 0.2 mM) were obtained to constrain the surface speciation of sulfate on ferrihydrite. The shape of the spectra was pH-dependent. The degree of nu(3) band splitting decreases with pH. Little difference of the spectra was found between different ionic strengths and sulfate loadings for the same pH. The little influence of ionic strength on the IR spectra reflects that the inner sphere and outer sphere species most likely do not exist simultaneously in the same pH conditions. Based on the IR spectra obtained from lower pH showing the splitting of nu(3) band to two peaks with activation of nu(1) band, the surface species is identified to be single inner sphere monodentate sulfate. The changes of spectra with pH are most likely attributable to the changes of the electric field strength posed to the sulfate on ferrihydrite surface, which is strongly pH-dependent.The predictive model for sulfate adsorption was constructed using an extended triple-layer model (ETLM). The pH adsorption edges and proton surface charges in the presence of sulfate as a function of ionic strength and sulfate concentration were obtained, respectively, from batch adsorption and acid-base titration experiments. The sulfate adsorption on ferrihydrite increases continuously with decreasing pH and ionic strength. These macroscopic adsorption data were analyzed using ETLM to retrieve the sulfate adsorption reaction and the equilibrium constant. Results of ETLM analyses showed that adsorption of sulfate on ferrihydrite is a single monodentate inner sphere process that is consistent with in situ infrared spectroscopic observation, as expressed by the following complexation reaction:2 FeOH + H+ + SO42- = ( FeOH) ( FeOSO3-) + H2O;where FeOH denotes a surface hydroxyl. Batch adsorption data from earlier studies of sulfates on ferrihydrite were reasonably reproduced using ETLM with the same adsorption reaction and equilibrium constant.Prediction of the effect of sulfate on trace dissolved anionic species adsorption on ferrihydrite was conducted using previously reported adsorption parameters for iodine and arsenic. The predictions showed that the adsorption of I and As(V) on ferrihydrite were diminished because of the competition with sulfate, although the adsorption of IO3- and As(III) were enhanced in the presence of sulfate. The sulfate surface species (( FeOH) ( FeOSO3-)) + possesses net negative charge. To compensate the negative surface charge, the formations of net positive surface species, which are dominant IO3- and As(III) surface species, are enhanced. The predictions demonstrated that sulfate strongly influences the adsorption behavior of trace anionic species on a ferrihydrite surface. (C) 2013 Published by Elsevier Ltd.

DOI： 10.1016/j.apgeochem.2013.06.013

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

The dehydration kinetics of serpentine was investigated using in situ high-temperature infrared microspectroscopy. The analyzed antigorite samples at room temperature show relatively sharp bands at around 3,655-3,660 cm(-1) (band 1), 3,570-3,595 cm(-1) (band 2), and 3,450-3,510 cm(-1) (band 3). Band 1 corresponds to the Mg-OH bond, and bands 2 and 3 correspond to OH associated with the substitution of Al for Si. Isothermal kinetic heating experiments at temperatures ranging from 625 to 700 A degrees C showed a systematic decrease of the OH band absorbance with heating duration. The one-dimensional diffusion was found to provide the best fit to the experimental data, and diffusion coefficients were determined with activation energies of 219 +/- A 37 kJ mol(-1) for the total water band area, 245 +/- A 46 kJ mol(-1) for band 1, 243 +/- A 57 kJ mol(-1) for band 2, and 256 +/- A 53 kJ mol(-1) for band 3. The results indicate that the dehydration process is controlled by one-dimensional diffusion through the tetrahedral geometry of serpentine. Fluid production rates during antigorite dehydration were calculated from kinetic data and range from 3 x 10(-4) to 3 x 10(-5) . The rates are high enough to provoke hydraulic rupture, since the relaxation rates of rocks are much lower than these values. The results suggest that the rapid dehydration of antigorite can trigger an intermediate-depth earthquake associated with a subducting slab.

DOI： 10.1007/s00269-013-0573-9

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OPTICAL SOC AMER  

Infrared (IR) spectroscopy is a versatile analytical method and nano-scale spatial resolution could be achieved by scattering type near-field optical microscopy (s-SNOM). The spectral bandwidth was, however, limited to approximately 300 cm(-1) with a laser light source. In the present study, the development of a broadband mid-IR near-field spectroscopy with a ceramic light source is demonstrated. A much wider bandwidth (at least 3000 to 1000 cm(-1)) is achieved with a ceramic light source. The experimental data on quartz Si-O phonon resonance bands are well reproduced by theoretical simulations indicating the validity of the present broadband near-field IR spectroscopy. (c) 2012 Optical Society of America

DOI： 10.1364/OE.20.011064

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Objectives. We had previously discovered that the flexural and tensile strengths of human dentin were 2-2.4 times greater after being heated to 140 degrees C, and deduced that the generation of higher-density structures and therefore dehydration probably promoted the increased strength. Our test hypotheses were that intertubular dentin, which constitutes a major part of organic components, was selectively affected by heating, and such changes could happen without critical damages to the basic structure of dentin type I collagen.Methods. Micro-mechanical changes of human dentin by heating at 140 degrees C were investigated by nano-indentation. Chemical changes in dentin collagen after heating were also investigated by X-ray diffraction study, a microscopic Fourier transform infrared (micro-FTIR) and a laser Raman spectroscopic analyses, and a cross-linking analysis by high-performance liquid chromatography.Results. The results of nano-indentation showed that the micro-hardness of intertubular dentin increased after heating at 140 degrees C to 1.8 times more than unheated dentin; on the other hand, peritubular dentin was unchanged. Results of X-ray diffraction showed that the lateral packing of collagen molecules shrank from 13.6 +/- 0.3 to 10.6 +/- 0.1 angstrom after heating, but the shrinkage reversed to the original after rehydration for seven days. After heating, no substantial chemical changes in the collagen molecules were detected in tests by micro-FTIR or Raman analyses, or by cross-linking analysis.Significance. These results suggest that intertubular dentin, which contains most of the type I collagen, was selectively affected by heating at 140 degrees C without critical damage to its collagen. (C) 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.dental.2011.11.015

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER  

We report the status of a scattering near-field microspectroscopy apparatus developed at SPring-8 using an infrared synchrotron radiation (IR-SR) source. It consists of a scattering type scanning near-field optical microscope and a Fourier transform infrared spectrometer. The IR-SR is used as a highly brilliant and broadband IR source. This apparatus has potential for application in near-field spectroscopy with high spatial resolution beyond the diffraction limit. In order to eliminate background scatterings from the probe shaft and/or sample surface, we used higher harmonic demodulation method. The near-field spectra were observed by 2nd harmonic components using the lock-in detection. The spatial resolution of about 300 nm was achieved at around 1000 cm(-1) (10 mu m wavelength). (C) 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.optcom.2011.12.106

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Domain-level identification of microbial cells or cell-like structures is crucial for investigating natural microbial communities and their ecological significance. By using micro-Fourier transform infrared (micro-FTIR) spectroscopy, we established a technical basis for the domain-level diagnosis and quantification of prokaryotic cell abundance in natural microbial communities. Various prokaryotic cultures (12 species of bacteria and 10 of archaea) were examined using micro-FTIR spectroscopic analysis. The aliphatic CH3/CH2 absorbance ratios (R-3/2) showed domain-specific signatures, possibly reflecting distinctive cellular lipid compositions. The signatures were preserved even after chemical cell fixation (formaldehyde) and nucleic acid staining (DAPI) processes - techniques that are essential in studying microbial ecology. The micro-FTIR technique was successfully applied for quantification of the bacteria/archaea abundance ratio in an active microbial mat community in a subsurface hot aquifer stream. We conclude that the micro-FTIR R3/2 measurement is both fast and effective for domain-level diagnosis and quantification of first-order prokaryotic community structures.

DOI： 10.1111/j.1758-2229.2011.00277.x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Polymerizations of organic monomers including amino acids, nucleotides and monosaccharides are essential processes for chemical evolution of life. Since these reactions proceed with "dehydration" reactions, they are possibly promoted if combined with thermodynamically favorable "hydration" reactions of minerals and salts. To test the possibility, we conducted heating experiments of the simplest amino acid "glycine (Gly)" mixed with four simple anhydrous salts (MgSO4, SrCl2, BaCl2 and Li2SO4) at 140 degrees C up to 20 days. Gly polymerization was strongly promoted by mixing with the salts in the order of MgSO4 > SrCl2 > BaCl2 > Li2SO4. Up to 6-mer of Gly polymers were synthesized in the Gly-MgSO4 mixture, and a total yield of Gly polymers attained about 7% of the initial amount of Gly by the 20 days heating. The total yield was about 200 times larger than that from the heating of Gly alone. XRD measurements of the Gly-MgSO4 mixture revealed the generation of MgSO4 monohydrate during Gly polymerization. These observations indicate that Gly polymerization was promoted by the salt hydrations through the hydration-dehydration interactions. Based on the observations, we tried to find a relationship between thermodynamic characteristics of the interactions and the promotion effects of each salt on Gly polymerization. It was found that the salts having lower hydration Delta(r)G(0) (easier to hydrate) promote Gly polymerization more strongly. The relationship was used to estimate promotion effects of simple oxide minerals on Gly polymerization. The estimations were consistent with previous observations about the effects of these minerals on Gly polymerization. The fact suggests that the hydration-dehydration interactions between amino acids and minerals are an important mechanism for amino acids' polymerizations on minerals. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.gca.2011.08.027

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Pore water in a porous rhyolite, having a porosity of 27% and pore radii ranging from >25 mu m to 0.008 mu m, was centrifugally extracted stepwise with increasing centrifugal speed to examine the potential variations of the compositions of pore water and their relationships to reaction and transport occurring in the rock. The rock was soaked for from 1 h to 7 days in an aqueous solution prior to centrifugation. To evaluate the effect of adsorption under minimum effect of dissolution, Li(+) and Br(-) were added to the solution as tracer ions. As centrifugal speed increased, water was extracted in order of large to small pores and the thickness of residual water film became thinner. The concentrations of ions dissolving from the rock (Na(+), K(+) Ca(2+), etc.) after 7 days of immersion were relatively constant in pores of 1-10 mu m radii and exponentially increased by 3-100 fold with decreasing pore radius to 0.1 mu m. These ions are dissolved from the rock and transported toward the exterior of the rock by diffusion. The calculation using a reactive-transport equation showed that the observed concentration changes reflect the change in solute distribution profile with pore size. The concentration of Si after 7 days of immersion was approximately constant or slightly decreased with increasing centrifugal speed, which appears to be controlled by the solubility. The concentration of Li(+) decreased with increasing centrifugal speed after 1 h of immersion but the trend changed after 7 days of reaction. Initial behavior of Li(+) is explained by adsorption on pore walls, and the change of trend is explained by desorption of that previously adsorbed, slight amounts of dissolution, and inflow from the outside of the rock. The change in concentration of Br(-) with increasing centrifugal speed was small, probably because Br- was not adsorbed on the surfaces. The sequential centrifugation thus provides information on the solute distribution associated with reaction and transport occurring in rock pores. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.apgeochem.2011.06.017

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OPTICAL SOC AMER  

In order to obtain broadband near-field infrared (IR) spectra, a Fourier-transform IR spectrometer (FT-IR) and a ceramic light source were used with a scattering-type scanning near-field optical microscope (s-SNOM). To suppress the background (far-field) scattering, the distance between the scattering probe and the sample was modulated with frequency Omega by a piezo-electric actuator, and the Omega component was extracted from the signal with a lock-in detection. With Omega=30 kHz, a peak-to-peak modulation amplitude of 198 nm, and a probe with smooth surface near the tip, broadband near-field IR spectra could be obtained in the 1200-2500 cm(-1). (C)2011 Optical Society of America

DOI： 10.1364/OE.19.012469

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC APPLIED SPECTROSCOPY  

Attenuated total reflection infrared (ATR-IR) spectroscopy was performed on glycerol/water solutions in order to gain a better understanding of the strong hydrogen bonding of glycerol as a humectant. The OH stretching band after eliminating the contribution of glycerol OH in the glycerol/water solutions was decomposed using three Gaussian components. With increasing glycerol concentrations up to 50 volume %, the decrease of the 3428 cm(-1) component (middle H-bond component) and the increase of the 3562 cm(-1) component (longer H-bond component) suggested the breaking of H bonds among water molecules. On the other hand, the 3242 cm(-1) component (shorter H-bond component) remained unchanged. It was expected that water molecules surrounding glycerol molecules are retained by strong H bonding between H atoms of water and O atoms in C-O of glycerol when aqueous solutions containing glycerol are introduced in human skin.

DOI： 10.1366/10-06183

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We report the results of near-field spectroscopy measurements performed using a scanning near-field optical microscopy system combined with an infrared synchrotron radiation source. The infrared synchrotron radiation is a highly brilliant white light source, and is tightly focused onto the probe tip. Strong background scattering is suppressed by modulating the distance between the probe and the sample. Higher harmonic components are extracted from the scattered light using a lock-in amplifier and examined for the presence of near-field signals. Near-field spectra in the mid-infrared region are measured by loading the higher harmonic components into a Fourier transform infrared spectroscopic apparatus. A striped metal pattern with a width of 1 μm printed on a glass substrate is found to be resolved at a wavelength of 9.8 μm. © 2011 The Surface Science Society of Japan.

DOI： 10.1380/ejssnt.2011.63

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The goal of the present study is to obtain broadband near-field infrared (IR) spectra by combining Fouriertransform infrared spectroscopy (FTIR) with scattering near-field optical microscopy (s-SNOM). A stage was added to the IR spectrometer with a ceramic light source in order to modulate the probe-sample distance, and the second harmonic component was extracted by a lock-in amplifier. The detected IR signal intensity decreased exponentially with the distance between the probe tip and an Au mirror, with a localization scale of approximately 100 nm. An area with Au islands formed by electron beam lithography was scanned with the modulation system with mapping steps of X = 80 nm and Y = 133 nm. The obtained IR intensity image matches the topographic image, indicating sub-micron spatial resolution. These results indicate that the addition of the modulation system to the broadband near-field IR spectrometer was successful in obtaining localized near-field signals and sub-micron spatial resolution, even using a ceramic IR light source. © 2011 The Surface Science Society of Japan.

DOI： 10.1380/ejssnt.2011.40

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Publisher：GEOCHEMICAL SOCIETY OF JAPAN  

DOI： 10.14862/geochemproc.58.0.175.0

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Language：Japanese   Publisher：The Physics Education Society of Japan  

DOI： 10.20653/pesj.59.2_132

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Attenuated total reflectance infrared (ATR-IR) spectroscopy was applied to investigate the structural change in dissolved glycine (H(3)(+)-N-CH(2)-COO(-)) with rising temperature from 27 to 150 degrees C The spectra were recorded using a heatable ATR-IR system, which was developed by Masuda et al. [1] This apparatus allows us to obtain the IR spectrum of aqueous solution at temperatures of up to 200 degrees C and under pressures of up to 30 MPa. Spectral analysis revealed the following changes in the covalent bond strength of glycine with rising temperature: (1) the N-H bonds of NH(3)(+) group became stronger, (2) the structure of COO(-) group became asymmetric owing to the strengthening of the electrostatic interaction between the NH(3)(+) group and COO(-) group, (3) the strengths of C-C bond and C-N bond became weaker These changes can be mainly attributed to the weakening of the hydrogen bond interaction between glycine and water molecules. The relationship between the structural change and the change in decomposition behavior of glycine with rising temperature was then evaluated It was interpreted that the decarboxylation and the deamination were caused by the weakening of C-C bond and C-N bond as well as the strengthening of NH(3)(+)COO(-) interaction with rising temperature (C) 2010 Elsevier B V. All rights reserved.

DOI： 10.1016/j.molstruc.2010.08.004

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MINERALOGICAL SOC AMER  

The change with temperature of IR absorption bands in OH in muscovite was studied using unpolarized in-situ high-temperature infrared microspectroscopy. The molar absorption coefficient epsilon at 3628 cm(-1) for OH in muscovite at room temperature (20 degrees C) has been determined to be 127 +/- 6 L/mol.cm. Using the orientation factor gamma= 0.47 for the angle between OH vector and c* axis (75 +/- 5 degrees), the true molar absorption coefficient epsilon at 3628 cm(-1) is determined to be 270 +/- 10 L/mol,cm at 20 degrees C. Integral molar absorptivities are also determined from 20 to 650 degrees C showing no weight loss. The value decreases from 7060 +/- 190 L/mol.cm(2) at 20 degrees C to 5190 +/- 270 L/mol.cm(2) at 650 degrees C (26% decrease). OH orientation of muscovite sample measured by polarized IR microspectroscopy at 20 C showed that the angle between the projection of OH vector to (001) plane (the OH' vector) and b axis is 30.5 degrees at 20 degrees C and did not change greatly at higher temperatures until 650 degrees C. The tilting of OH dipoles toward the c* axis from 75 degrees to about 43 degrees while keeping the same angles along b axis would explain the observed decrease in integral molar absorptivities at higher temperatures, but further studies are needed to clarify the OH behavior at high temperatures.

DOI： 10.2138/am.2010.3235

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

Distributions of organic functional groups as well as inorganic features were analyzed in the Bells (CM2) carbonaceous chondrite using near-field infrared (NFIR) spectroscopy. NFIR spectroscopy has recently been developed to enable infrared spectral mapping beyond the optical diffraction limit of conventional Fourier transform infrared microspectroscopy. NFIR spectral mapping of the Bells 300 nm thick sections on Al plates for 7.5 x 7.5 mu m(2) areas showed some C-H-rich areas which were considered to represent the organic-rich areas. Heterogeneous distributions of organic matter as well as those of inorganic phases such as silicates (Si-O) were observed with 1 mu m spatial resolution. The NFIR mappings of aliphatic C-H (2960 and 2930 cm) 1) and structural OH (3650 cm) 1) confirm that organic matter is associated with phyllosilicates as previously suggested. The NFIR mapping method can provide 1 mu m spatial distribution of organic functional groups and their association with minerals. High local sensitivity of NFIR enables us to find organic-rich areas and to characterize them by their aliphatic CH2/CH3 ratios. The aliphatic CH2/CH3 ratio of Bells is slightly higher than Murchison, similar to Orgueil, and lower than literature values of IDPs and cometary dust particles.

DOI： 10.1111/j.1945-5100.2010.01030.x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Dehydration behavior of muscovite flake was investigated at 760-860A degrees C by using in situ high-temperature IR microspectroscopy for the OH absorption band around 3,620 cm(-1). Isothermal kinetic heating experiments at each temperature gave detailed decrease curves of the OH band area with time. These curves have been simulated by the first and second order reactions or mono- and two-dimensional diffusion processes. The mono-dimensional diffusion was found to give the best fit to the experimental data and apparent diffusion coefficients D were determined at 760-860A degrees C with the activation energy of 290 +/- A 20 kJ/mol. The apparent diffusion coefficients D varied with the sample thickness L. This variation can be explained by an m layers model with a unit length of L' with a constant diffusion coefficient D'. Therefore, the dehydration process might be rate-limited by mono-dimensional diffusion through tetrahedral silicate sheet perpendicular to (001) planes of muscovite with a unit length of L'.

DOI： 10.1007/s00269-009-0313-3

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Publishing type：Part of collection (book)  

© 2010 Taylor & Francis Group, London. In-situ heating infrared micro-spectroscopy has been tested for determining kinetic parameters of aliphatic CH decrease of humic substances. The numerous data points of aliphatic CH peak heights at 2930 cm−1 with an interval of 90 seconds during the isothermal heating at 260–310°C of a test material could be well fitted by a combination of two first order reactions with different activation energy and frequency factor values. Detailed kinetics of aliphatic CH decrease of humic substances can be studied by this new method by using well characterized appropriate kerogens for petroleum/gas formation.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

To evaluate kinetic parameters for thermal degradation of organic matter, in situ heating experiments of insoluble organic matter (IOM) and bulk of Murchison (CM2) meteorite were conducted under Fourier transform infrared micro-spectroscopy combined with a heating stage. Decreases of aliphatic C-H band area under Ar flow were well fitted with Ginstling-Brounshtein three-dimensional diffusion model, and the rate constants for decreases of aliphatic C-H were determined. Activation energies E-a and frequency factors A obtained from these rate constants at different temperatures using the Arrhenius equation were E-a = 109 +/- 3 kJ mol(-1) and A = 8.7 x 10(4) s(-1) for IOM, and E-a = 61 +/- 6 kJ mol(-1) and A = 3.8 s(-1) for bulk, respectively. Activation energy values of aliphatic C-H decrease are larger for IOM than bulk. Hence, the mineral assemblage of the Murchison meteorite might have catalytic effects for the organic matter degradation. Using obtained kinetic expressions. the time scale for metamorphism can be estimated for a given temperature with aliphatic C-H band area, or the temperature of metamorphism can be estimated for a given time scale. For example, using the obtained kinetic parameters of mm, aliphatic C-H is lost approximately within 200 years at 100 degrees C and 100 Myr at 0 degrees C. Assuming alteration period of 7.5 Myr, alteration temperatures could be calculated to be <15 +/- 12 degrees C. Aliphatic C-H decrease profiles in a parent body can be estimated using time-temperature history model. The kinetic expression obtained by the infrared spectral band of aliphatic C-H could be used as an alternative method to evaluate thermal processes of organic matter in carbonaceous chondrites.

DOI： 10.1111/j.1945-5100.2009.01008.x

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Language：Japanese   Publisher：The Geochemical Society of Japan  

We investigated contents of the noble gas and water of tektite-like materials collected from several localities within Hainan Island, China. The island is located in the northern edge of the Australasian strewn filed, and has been known as providing different types of tektites. One of the major objectives of this study is to identify the samples as tektites and to classify them into subtypes based on the analytical results. Noble gas compositions, as expected for tektites, are characterized by neon enrichment, while the Ne/Ar ratios are smaller than that of normal-type tektites, indicating consistent feature to that of previously reported Muong Nong-type tektites. Range of water contents agrees with those reported for Muong Nong-type tektites. Together with apparent morphological similarities between our samples and Muong Nong-type tektites, our results provide strong evidence to conclude that the studied samples are Muong Nong-type tektites. Since the Muong Nong-type tektites are formed relatively closer to impact craters, our findings and further studies on the Muong Nong-type tektites will help to narrow out the possible location of the source crater of the Australasian tektites.

DOI： 10.14934/chikyukagaku.44.43

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER HEIDELBERG  

Eight unmelted Antarctic micrometeorite (AMMs) recovered from Kuwagata Nunatak were Studied oil Al-foils by infrared (IR), Raman, and visible reflection micro-spectroscopy in combination with electron microscopy. Major element abundances of the AMMs studied were found to be similar to solar abundance, although all have the common characteristic of Mg-depletion. Absorption hands around 500 run were detected for some of the AMMs by the visible micro-spectroscopic method, and these AMMs can be assigned to Fe-hydroxide-like materials. These results suggest that the studied AMMs experienced weathering in Antarctica. Four grains showed file presence of IR H2O and CH hands similar to those of type 2 carbonaceous chondrites, while these were found to be absent in two grains, as in type 3 carbonaceous chondrites. D (disordered: 1360 cm(-1)) and G (graphite: 1600 cm(-1)) Raman hand features of graphitic carbonaceous materials in these AMMs were not similar to those for type 3 but were rather close to those for type 2 and 1 carbonaceous chondrites, although some data showed it degree of deviation. The genetic classification of individual AMM grains can thus be Studied by these methods, although the weathering effects and the atmospheric entry heating oil organics and hydrous components need to be evaluated. These multiple micro-spectroscopic reflectance methods are useful for file characterization of precious small samples.

DOI： 10.5047/eps.2008.11.001

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Eight unmelted Antarctic micrometeorite (AMMs) recovered from Kuwagata Nunatak were studied on Al-foils by infrared (IR), Raman, and visible reflection micro-spectroscopy in combination with electron microscopy. Major element abundances of the AMMs studied were found to be similar to solar abundance, although all have the common characteristic of Mg-depletion. Absorption bands around 500 nm were detected for some of the AMMs by the visible micro-spectroscopic method, and these AMMs can be assigned to Fe-hydroxide-like materials. These results suggest that the studied AMMs experienced weathering in Antarctica. Four grains showed the presence of IR H2O and CH bands similar to those of type 2 carbonaceous chondrites, while these were found to be absent in two grains, as in type 3 carbonaceous chondrites. D (disordered: 1360 cm-1) and G (graphite: 1600 cm-1) Raman band features of graphitic carbonaceous materials in these AMMs were not similar to those for type 3 but were rather close to those for type 2 and 1 carbonaceous chondrites, although some data showed a degree of deviation. The genetic classification of individual AMM grains can thus be studied by these methods, although the weathering effects and the atmospheric entry heating on organics and hydrous components need to be evaluated. These multiple micro-spectroscopic reflectance methods are useful for the characterization of precious small samples. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS).

DOI： 10.5047/eps.2008.11.001

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

The adsorption behavior of lysine on montmorillonite in aqueous solution was investigated by in situ attenuated total reflectance infrared (ATR-IR) spectroscopy. To distinguish the protonation states of a-amino group, side-chain amino group and carboxyl group in lysine structure using ATR-IR spectra (i.e., NH(2) versus NH(3)(+) and COO(-) versus COOH), pH-induced spectral changes of dissolved lysine were firstly measured and correlated with the thermodynamically calculated dissociation states of lysine (di-cationic, cationic, zwitterionic and anionic states). The obtained result was applied to interpret the ATR-IR spectra of lysine adsorbed on montmorillonite. We found that the adsorbed lysine was dominantly present as cationic state over the whole range of tested pH (pH = 4.9-9.7). This indicates that the adsorption is mainly driven by electrostatic interaction between the negatively charged montmorillonite surface and positively charged cationic lysine. We also found that lysine interacts with montmorillonite surface through the protonated side-chain amino group. This result suggests that lysine has a preferred vertical orientation, with the side-chain amino group pointing toward the surface. (C) 2009 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jcis.2009.06.061

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Precambrian microbial fossils show carbonaceous cellular structure, which often resemble in shape and size cyanobacteria and other prokaryotes. Morphological taxonomy of these minute, simple, and more or less degraded fossils is, however, often not enough to determine their precise phylogenetic positions. Here we report the results of micro-FTIR spectroscopic analyses of well-preserved microfossils in similar to 850 Ma and similar to 1900 Ma stromatolites, together with those of 8 species of extant prokaryotes and 5 of eukaryotes for comparison. These Proterozoic fossils have low CH3/CH2 absorbance ratios (R-3/2 < 0.5) of aliphatic CH moieties, suggesting selective preservation of long, straight, aliphatic carbon chains probably derived from bacterial membrane lipids. All the observed R-3/2 values of coccoids, filaments and amorphous organic matter resemble lipid fractions of extant Bacteria including cyanobacteria, but not Archaea. The results indicate that Proterozoic microfossils belong to Bacteria,which is consistent with the cyanobacterial origin inferred from morphology. Moreover, the R3/2 Value of fossilized cell would reflect chemical composition of its precursor membrane lipid, thus could be a useful new tracer for distinguishing Archaea, Bacteria and possibly Eucarya for fossilized and extant microorganisms. (C) 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.precamres.2009.03.006

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MINERALOGICAL SOC AMER  

Incorporation of water in anhydrous synthetic beryl was studied at 500-700 degrees C and 50-150 MPa of confining water pressure to measure the diffusion of water molecules along the channels in a cyclosilicate. A series of polarized IR spectra series were taken with E parallel to the channel direction, which is parallel to the c-axis, along a traverse parallel to this axis. Water concentration profiles were determined from absorbance of H(2)O peaks. The IR spectra showed that the dominant diffusing species is type I water molecule, whose H-H vector is parallel to the c-axis (sharp peak at 3700 cm(-1)). No pressure dependence on water diffusivity can be recognized under these experimental conditions. The Arrhenius relation gives the activation energy of 133 +/- 12 kJ/mol, with a pre-exponential factor of 10(-2.6) (cm(2)/s). Diffusion of water is much faster in the beryl channels than Volume diffusion in other silicates, but the activation energy and diffusion coefficient values for beryl are similar to the corresponding values previously reported for grain boundary diffusion in quartz aggregates.

DOI： 10.2138/am.2009.3124

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Diffusion is one of the main mechanisms of solute transport in pore water of geologic media. The effective diffusion coefficient of a solute in a rock is usually measured by the through-diffusion experiment. However, in this experiment, the effect of advection, induced by density difference between dense aqueous solution and pure water, has not been considered. To evaluate the effect of density-driven flow, a through-diffusion experiment using Fontainebleau sandstone was conducted for KCl and KI aqueous solutions with various densities. The measured effective diffusion coefficients were positively correlated with the density difference; the effective diffusion coefficient of a 1 M KI solution (density difference, 0.119 g/cm(3)) was one order of magnitude larger than that of a 0.1 M KCl solution (density difference, 0.005 g/cm(3)). The result is explained by a theoretical model using a diffusion-advection equation including Darcy's law. Based on the theory, a diagram to evaluate the condition at which the measured effective diffusion coefficient does not include the effect of advection is presented. (C) 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jconhyd.2009.02.006

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

Organic contamination (similar to 2965 and similar to 1260 cm(-1) peaks) was found on Tagish Lake (C2) and Murchison (CM2) carbonaceous chondrites containing abundant hydrous minerals by Fourier transform infrared (FTIR) microspectroscopy oil the samples pressed on Al plates. On the other hand, anhydrous chondrite (Moss, CO3) was not contaminated. This contamination occurred within one day of storage, when the samples pressed on Al were stored within containers including silicone rubber mats. Volatile molecules having similar peaks to the contaminants were detected by long-path gas cell FTIR measurements for the silicone rubber mat. Rapid adsorption of the volatile contaminants also Occurred when silica gel and hydrous minerals such as serpentine were stored in containers including silicone rubber, silicone grease, or adhesive tape. However, they did not show any contamination when stored in glass and polystyrene containers without these compounds. Therefore, precious astronomical samples such as meteorites, interplanetary dust particles (IDPs), and mission-returned samples from cornets, asteroids, and Mars, should be measured by micro FTIR within one day of storage in glass containers without silicone rubber, silicone grease, or adhesive tape.

DOI： 10.1111/j.1945-5100.2009.tb00750.x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Colors of plinian pumices were measured by spectrocolorimetry, and their quantitative color parameters in the L*a*b* color space were determined. A series of heating experiments of obsidian was conducted to simulate the color-change processes of rhyolitic glasses. In these experiments, following three stages of color-change processes were observed. Stage I showed a rapid b* (yellowishness) increase associated with fast dehydration controlled by water diffusivity (D (water)). In stage II, a* (reddishness) increase was accompanied by Fe(2+) decrease. Both a* increase and Fe(2+) decrease can be simulated by a diffusion model. Obtained diffusivity D (oxidation) were about two orders of magnitude smaller than D (water) . The a*-value increase after the oxidation in stage III appeared to be quasi-linear with time, indicating the zeroth order reaction corresponding to the formation of hematite-like structures in rhyolitic glasses. The diffusion-limited a* increase model in stage II was applied to a natural plinian pumice fall unit to evaluate time periods of color-change processes through oxidation by air of fragmented rhyolitic materials.

DOI： 10.1007/s00445-008-0202-5

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Carbonaceous chondrites are known to contain up to a few wt % organic carbon. Organic materials are disseminated in the clayish matrix, and some of them have been reported to be in the form of submicron organic globules. However, little is known about the nature of these microscopic organics. The organic matter distribution of the Bells (CM2) carbonaceous chondrite has been studied using a near-field infrared (NFIR) microspectrometer. Organic matter distribution and mineral associations at the submicron scale spatial resolution were observed.

DOI： 10.1246/cl.2009.22

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

Attenuated total reflectance infrared (ATR-IR) spectroscopy was employed to quantitatively evaluate the dissociation states (di-cationic, cationic. zwitterionic, and anionic) of lysine adsorbed on amorphous silica. To determine the relationship between the ATR-IR spectra and each dissociation state, we first measured pH-induced Spectral changes of dissolved lysine and correlated these changes with the thermodynamically calculated dissociation states of lysine. This procedure yielded calibration curves with good linearity: we used these curves for the quantitative analysis of adsorbed lysine. our analysis revealed that 81 +/- 5% of the lysine adsorbed on amorphous silica was present in a cationic state and 19 5% was in a zwitterionic state; these percentages remained mostly Unchanged over the whole range of pH values tested (pH = 7.1-9.8). We interpret the values obtained to indicate that lysine adsorption is mainly driven by electrostatic interaction with the negatively charged Silica surface (Si-O(-)center dot center dot center dot Lys(+), Si-O(-)center dot center dot center dot Lys(+/-) (C) 2008 Elsevier Inc. All rights reserved

DOI： 10.1016/j.jcis.2008.09.072

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MINERALOGICAL SOC AMER  

We measured visible reflectance spectra and colors of hematite (alpha-Fe2O3) reagent powders and a natural feldspar grain containing dispersed hematite microcrystals from room temperature LIP to 800 degrees C using an in situ, high-temperature visible micro-spectrometer with dark field optics. The spectrum of room-temperature hematite powder is characterized by a nearly constant reflectivity in the range 400-550 nm, a shoulder near 620 nm, and a reflectivity maximum near 750 nm. The reflectance spectrum is similar to the diffuse reflectance spectra Measured by a spectrophotometer and a conventional spectrometer with an integrating sphere. This result indicates that the dark field objective is Suitable for measuring visible reflectance spectra of hematite powders with the visible micro-spectrometer. The reflectance of hematite powders in the longer wavelength region (>550 nm) decreases gradually With increasing temperature. The shoulder centered around 620 nm and the reflectance maximum near 750 nm also become indistinct at high temperatures. The calculated L* (dark-light), a* (red-green). and b* (blue-yellow) color values decrease with increasing temperature. This means that the red color of hematite becomes black with temperature increase. The calculated absorption intensities (Kubelka-Munk functions) Suggest that this temperature dependence of the hematite powder-reflectance spectra can be mainly explained by a change in hand gap absorption edges for a semiconductor (Urbach rule). The visible spectra and colors of a natural feldspar grain containing dispersed hematite microcrystals show a similar change with temperature, indicating that the temperature dependence can be observed under natural conditions at high temperatures, Such as in volcanic eruptions.

DOI： 10.2138/am.2009.2779

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER GEOPHYSICAL UNION  

We present major element and volatile concentration analyses in melt and gas inclusions from two recent picrite eruptions (February 2005 and December 2005) at Piton de la Fournaise volcano (La Reunion Island, Indian Ocean). Combined with literature data, our new data show that the large variability of major element compositions in Piton de la Fournaise lavas may be explained by three depth-dependent differentiation stages of a single transitional parental magma (9-11 wt% MgO; 0.5-0.8 wt% K2O, and 10-12 wt% CaO). The deepest differentiation (>7.5 km) is controlled by the fractional crystallization of clinopyroxene + plagioclase and yields gabbros and basalts enriched in K and depleted in Ca relative to the parental magma. In a shallower storage zone (<2.5 km), differentiation of the transitional parental magma is dominated by the fractionation/accumulation of Fo(83-85) olivine phenocrysts, yielding Mg-poor basalts at the top of the reservoir and picrites at the base. In cooling dykes and subsurface pockets (<0.6 km), Mg-poor basalts may themselves evolve into more differentiated melts by clinopyroxene + plagioclase fractionation. The incorporation of dunitic xenocrysts or other xenoliths is not necessary to explain the major element chemical diversity of the volcano. The same superposition of differentiation mechanisms may occur at similar depths in other shield volcanoes.

DOI： 10.1029/2008GC002015

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Language：Japanese   Publisher：日本地球化学会  

生命起源においてアミノ酸重合反応は重要なプロセスである．アミノ酸の重合速度にはpHが影響することが知られているが，定量的な解析はされていない．そこで本研究では，グリシン(Gly)を用いて速度論的パラメーターを求めた．NaOH，HClでpHを4から12に調整したGly水溶液の加熱実験を行い，液体クロマトグラフィーで生成物を分析した．反応経路はGlyからGlyGlyが生成し，さらにDKPが生成すると推定し，反応速度定数を求めた．重合速度はpHに大きく依存し，pH 9から10で極大値を示した．Glyの各解離状態での重合速度を求めると，両性イオンと陰イオンの重合が最も速いことが分かった．よって，両性イオンと陰イオンが約半数ずつ存在する状態（pH 9.8）で，全体の重合速度が最も速くなると推測される．解離状態による反応性の違いは，アミノ基の求核性，分子間及び分子内の電気的相互作用に起因すると考えられる．

DOI： 10.14862/geochemproc.56.0.145.0

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Language：Japanese   Publisher：The Japanese Society for Planetary Sciences  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER  

We measured quantitatively colors of volcanic ash deposits erupted from three different styles of summit activity (Strombolian activity, Vulcanian explosions and continuous ash venting activity) at Sakurajima volcano from 1974 to 1985. Colors of Strombolian ash samples have larger yellow components of their visible spectra (b* values) than those of explosion and continuous venting ash samples. Colors of explosion ash samples show larger variation in both red and yellow components of their visible spectra (a* and b* values, respectively), while colors of continuous venting ash samples are in the narrow ranges within colors of g explosion ash samples. Colors of components with lower densities than 3.1 g/cm(3) (groundmass and phenocrystic plagioclase) obtained by magnetic and heavy liquid separation methods are similar to the unseparated bulk ash samples. This result suggests that the color variations of ash deposits are mainly originated from the particles composed of groundmass. The particles can be classified into three different types of particles with different vesicularity and crystallinity (vesicular particle [VP], dense particle with vesicles [DPV] and dense particle without vesicles [DP]). Analytical results of component proportions, chemical compositions of groundmass glasses, ferrous iron contents and surface ferric materials show that (1) VP has larger yellow components of the visible spectrum (b* values) and high ferrous iron content, and is less crystallized than the DP and DPV, (2) DP has larger red and yellow components of its visible spectrum (a* and b* values, respectively) and involves ferric materials on the surfaces produced by oxidation process, and (3) DPV has smaller red and yellow components of its visible spectrum (a* and b* values, respectively) and involves less ferric materials on the ash surfaces. Color differences of ash deposits from three different activity styles can be explained by the different mixing ratios of VP, DPV and DP. During the Strombolian activity, the VP is a main component in the ash, which is formed from relatively less degassed and crystallized magma. In the Vulcanian explosion and continuous ash venting activity, the proportions of DPV and DP in ash are larger than that in the Strombolian activity. The highly crystallized DP may correspond to a vent cap, and DPV to a magma below the cap. The color measurements of ash deposits provide information on the pre-eruptive processes at the shallower levels of a conduit. (C) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jvolgeores.2007.11.013

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER  

Permeability measurement of quenched volcanic porous materials is an important approach to understand permeability development and degassing of vesicular silicic magmas. In this study, we developed a gas permeameter to measure permeability of natural samples and experimental products. The permeameter has broad measurement ranges of pressure difference (10(1)-10(5) Pa) and gas-flow rate (10(-9)-10(-5) m(3)/s). These ranges enable us to measure viscous permeability in the range of 10(-17)-10(-9) m(2) for 1 centimeter-scale samples, using the Forchheimer equation, which includes the inertial effect of gas flow permeating through the samples. In addition, we improved the procedure for performing permeability measurements of mm-sized products of decompression experiments. Although a previous study reported the first permeability data for vesicular silicic glass products of decompression experiments, we found an overestimation in their permeability data due to problems in sample preparation, especially for very low permeability samples. Our improved measurements give lower permeability values than those of Takeuchi et al. (2005)(Takeuchi, S., Nakashima, S., Tomiya, A., Shinohara, H., 2005. Experimental constraints on the low gas permeability of vesicular magma during decompression. Geophys. Res. Lett., 32, L10312 doi:10.1029/2005GLO22491).We also evaluated the inertial effect on apparent permeability calculated using Darcy's law under the conditions of permeability measurement and magmatic degassing. The permeability measurements indicate that the apparent permeabilities of highly permeable samples (>10(-10) m(2) in viscous permeability) are affected considerably by the inertial effect under a high-pressure gradient (> 10(5) Pa/m) and reduced by more than 0.5 orders of magnitude from their viscous permeabilities. Also under magmatic conditions, the reduction of apparent permeability by more than 0.5-1.0 orders of magnitude may occur during the degassing of highly permeable magmas driven by a high-pressure gradient. (c) 2008 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jvolgeores.2008.05.010

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN ASSOC MINERALOGICAL SCIENCES  

In order to study physicochemical states of water in a chalcedony, thin sections were heated from room temperature (RT) to 400 degrees C at 50 degrees C intervals under an infrared (IR) microscope. A sharp IR absorption band due to hydroxyls (Si-OH) shifts linearly from 3585 cm(-1) at RT to 3599 cm(-1) at 400 degrees C (1.8 cm(-1)/50 degrees C). A broad band due to H2O shifts also linearly from 3425 cm(-1) at RT to 3535 cm(-1) at 400 degrees C (15 cm(-1)/50 degrees C). These reversible band shifts, without dehydration, of hydroxyl and H2O can be explained by the increasing hydrogen bond distance and the decreasing coordinating numbers of water molecules, respectively.The in-situ IR spectra of the chalcedony thin sections during the isothermal heating at 550 degrees C showed a decrease of the total water band area. The RT spectra quenched from 550 degrees C indicated the major decrease of 3585 cm(-1) absorbance due to Si-OH with the minor decrease of the 3425 cm(-1) absorbance due to H2O. These results suggest the dominant dehydration of Si-OH species from the microcrystalline quartz and the certain stability of liquid-like H2O against dehydration in pores and grain boundaries.

DOI： 10.2465/jmps.071022a

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

DOI： 10.1016/j.ijrmms.2007.07.008

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Fourier transform infrared (FTIR) microanalysis of pseudotachylytes (i.e. friction-induced melts produced by seismic slip) from the Nojima fault (Japan) reveals that earthquakes almost instantaneously expel 99 wt.% of the wall rock CO2 content. Carbon is exsolved because it is supersaturated in the friction melts. By extrapolation to a crustal-scale fault rupture, large events such as the M7.2 Kobe earthquake (1995) may yield a total production of 1.8 to 3.4 x 10(3) tons CO2 within a few seconds. This extraordinary release of CO2 can cause a flash fluid pressure increase in the fault plane, and therefore enhance earthquake slip or trigger aftershocks; it may also explain the anomalous discharge of carbon monitored in nearby fault springs after large earthquakes. Because carbon saturation in silicate melts is pressure-dependent, FTIR can be used as a new tool to constrain the maximum depth of pseudotachylyte formation in exhumed faults. (C) 2007 Elsevier B.V. All fights reserved.

DOI： 10.1016/j.epsl.2007.10.041

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The mechanism and rate of hydration of rhyolitic glass during weathering were studied. Doubly polished thin sections of two rhyolites with different duration of weathering (Ohsawa lava: 26,000 yr, Awanomikoto lava: 52,000 yr) were prepared. Optical microscope observation showed that altered layers had developed along the glass surfaces. IR spectral line profile analysis was conducted on the glass sections from the surface to the interior for a length of 250 mu m and the contents of molecular H2O (H2Om), OH species (OH) and total water (H2O1) were determined. The diffusion profile of H2Om in Ohsawa lava extends beyond the layer observed by optical microscope. The content of H2Om in the hydrated region is much higher than that of OH species. Thus, the reaction from H2Om to OH appears to be little and H2Om is the dominant water species moving into the glass during weathering. Based on the concentration profiles, the diffusion coefficients of H2Om (DH2Om) and (HOt)-O-2 (DH2O1) were determined to be 2.8 x 10(-10) and 3.4 x 10(-10) mu m(2) s(-1) for Ohsawa lava, and 5.2 x 10(-11) and 4.1 x 10(-11) mu m(2) s(-1) for Awanomikoto lava, respectively. The obtained DH2Om during weathering are more than 2-3 orders of magnitude larger than the diffusion coefficient at similar to 20 degrees C that is extrapolated from the diffusivity data for >400 degrees C. This might suggest that the mechanism of water transport is different at weathering conditions and >400 degrees C. (c) 2007 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.gca.2007.10.018

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Publisher：GEOCHEMICAL SOCIETY OF JAPAN  

Polymerization reaction of amino acid is an essential process for chemical evolution to life. Although it is known that solution pH significantly influence the rate of the polymerization reactions, the quantitative effects of pH have not yet investigated. In this study, the effects of pH on the rate of polymerization of Gly was quantitatively evaluated. 8-10ml of 100mM Gly solutions, having pH from 7 to 10, were poured into Teflon bottles and heated at 140 and 160°C from 1 to 14 days. After the heating procedure, the concentrations of Gly, GlyGly, DKP were measured by HPLC.It revealed that DKP is firstly composed from Gly, and then GlyGly was composed from DKP. At higher pH, the first order reaction rate constant of GlyGly formation becomes higher.

DOI： 10.14862/geochemproc.55.0.159.0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN ASSOC MINERALOGICAL SCIENCES  

Changes in the absorption intensity (absorbance) at 254 nm of a fulvic acid solution in the presence of goethite powder were monitored in situ in a liquid cell at a temperature of 80 degrees C in a UV-visible spectrometer. The absorbance at 254 nm decreased rapidly with time in the initial stage in the presence of goethite with a first-order rate constant of k(1)(UV) = 3 x 10(-4) S-1. while in the absence of goethite, the absorbance at 254 nm decreased slowly with time, with a first-order rate constant of k(0)(UV) = 6 x 10(-7) s(-1). A hydrothermal vessel was connected to a long-path gas cell infrared spectrometer to monitor the volatile compounds formed on heating the fulvic acid at 80 degrees C. Carbon dioxide formed gradually over time from the fulvic acid solution in the absence of goethite (k(0)(CO2) = 1.5 x 10(-6) s(-1)). The formation of CO2 in the presence of geothite occurred via two first-order reactions. The initial first-order rate constant of CO2 formation from fulvic acid in the presence of goethite (k(1)(CO2) = 3.2 x 10(-4) s(-1)) had the same magnitude as the decrease in absorbance at 254 nm. The second rate constant of CO2 formation (k(2)(CO2) = 1.8 X 10(-6) s(-1)) had the same magnitude as CO2 formation in the absence of goethite. These results suggest that the formation of CO2 from the fulvic acid is greatly accelerated by the presence of goethite, possibly through the adsorption of the fulvic acid on the goethite surface with subsequent redox reactions occurring.

DOI： 10.2465/jmps.070619c

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：INST PURE APPLIED PHYSICS  

The stability of methyl radicals formed in synthetic methane hydrate by gamma-ray irradiation at 77 K was studied at 200-273 K and 10 MPa. The methyl radicals decayed under these conditions, despite the stability of methane hydrate, and changed into other molecules that could not be detected by electron spin resonance (ESR). Decay products were investigated by gas cell infrared (IR) spectroscopy by measuring the decomposed gas from the gamma-irradiated methane hydrate. Only ethane molecules were detected from the irradiated sample, while these were absent in an unirradiated sample. The molar ratio of ethane to methane (C2H6/CH4) was 12 +/- 1 ppm, which did not contradict with that of methyl radical to methane (CH3./CH4) in the literature. Hence, most of the methyl radicals generated by irradiation were supposed to be transformed to ethane in methane hydrate.

DOI： 10.1143/JJAP.46.455

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Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (scientific journal)  

In situ infrared (IR) and Raman microspectroscopy have been conducted on Neoproterozoic, organic-walled microfossils (prokaryotic fossils) in doubly polished, petrographic thin sections in order to detect their spectral signatures. The microfossils are very well preserved and occur in black chert from the approximately 850 million-year-old Bitter Springs Formation, Northern Territory, Australia. Raman microspectroscopy on two species of microfossils, one a filament and the other a coccoid, shows disordered peaks (D peak, 1340 cm(-1)) and graphite peaks (G peak, 1600 cm(-1)), indicating that they consist of disordered carbonaceous materials. IR micro-mapping results of the filament reveal that the distributions of peak heights at 2920 cm(-1) (aliphatic CH(2)), 1585 cm(-1) (aromatic C-C), and 1370 cm(-1) (aliphatic CH(3)) match the shape of the filamentous microfossil. These results suggest that IR microspectroscopy can be used for in situ characterization of organic polar signatures that morphologically indicate microfossils embedded in chert by using doubly-polished rock (petrographic) thin section samples. Further, these methods can be applied to controversial microfossil-like structures to test their biogenic nature.

DOI： 10.1366/000370206778664707

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC APPLIED SPECTROSCOPY  

In situ infrared (IR) and Raman microspectroscopy have been conducted on Neoproterozoic, organic-walled microfossils (prokaryotic fossils) in doubly polished, petrographic thin sections in order to detect their spectral signatures. The microfossils are very well preserved and occur in black chert from the similar to 850 million-year-old Bitter Springs Formation, Northern Territory, Australia. Raman microspectroscopy on two species of microfossils, one a filament and the other a coccoid, shows disordered peaks (D peak, 1340 cm(-1)) and graphite peaks (G peak, 1600 cm(-1)), indicating that they consist of disordered carbonaceous materials. IR micro-mapping results of the filament reveal that the distributions of peak heights at 2920 cm-1 (aliphatic CH2), 1585 cm-1 (aromatic C-C), and 1370 cm-1 (aliphatic CH3) match the shape of the filamentous microfossil. These results suggest that IR microspectroscopy can be used for in situ characterization of organic polar signatures that morphologically indicate microfossils embedded in chert by using doubly-polished rock (petrographic) thin section samples. Further, these methods can be applied to controversial microfossil-like structures to test their biogenic nature.

DOI： 10.1366/000370206778664707

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Language：English   Publisher：SPRINGER  

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Dehydration experiments on basaltic, andesitic and dacitic glasses with 1.1, 0.7 and 1.0 wt.% total water, respectively, were performed at 400-675 °C and 0.1 MPa. The dehydration rates were measured by in situ infrared (IR) spectroscopy and modeled by assuming the diffusion of one component water (total water). The diffusivities of total water in basalt and dacite were found to be linearly dependent on total water contents, but that in andesite was weakly dependent on or independent of total water contents at water content and temperature ranges of this study. The total water diffusivities in basalt and dacite were determined by assuming the linear-dependent diffusivity on total water contents and that in andesite was obtained by assuming the constant diffusivity. The obtained diffusivities of total water D (μm2/s) can be expressed by the following equations: DBasalt = C/C0exp[(20.2±2.1) - (166,000±13,000)/RT] DAndesite = exp[(12.4±1.4) - (138,000±10,000)/RT] DDacite = C/C0exp[(13.9±0.9) - (133,00 0±6000)/RT], where C is the total water contents in weight perce nt; C0, reference total water contents of 1.1 and 1.0 wt.% for basalt and dacite, respectively; and T, temperature in Kelvin. These equations cover the temperature ranges of 400-575, 500-675 and 500-675 °C, and the water content ranges of <1.1, 0.7 and 1.0 wt.% for basalt, andesite and dacite, respectively. The obtained diffusivities of total water in basalt, andesite and dacite and previous data for water diffusivity in rhyolite show that at 0.7 wt.% and 400-675 °C, the total water diffusivity decreases from rhyolite to andesite, but the total diffusivity in basalt is higher than that in dacite and lower than that in rhyolite. On the other hand, the results of this study predict that the diffusivities of total water in basalt to rhyolite increase with depolymerization of silicate structures at higher temperatures, which results from the crossovers of diffusivity-temperature trends. © 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.chemgeo.2005.09.009

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Infrared spectroscopy and ion micro-probe measurements showed that the major constituent minerals of eclogites from the Kokchetav massif, which have been subducted to ∼180 km depths, contain significant amounts of water up to 870 ppm H2O (by weight) in omphacite, 130 ppm H2O in garnet and 740 ppm H2O in rutile. Omphacite shows three hydroxyl absorption bands at 3440-3460, 3500-3530 and 3600-3625 cm-1, garnet has a single band at 3580-3630 cm-1 and rutile has a single sharp band at 3280 cm-1. The hydroxyl absorbance at these wavenumbers changes with the crystal orientation in polarized infrared radiation, indicating that the water is structurally incorporated in these minerals. The water contents in omphacite and garnet increase systematically with the metamorphic pressure of the host eclogites. The partitioning coefficient of the water content between coexisting garnet and omphacite is similar in different eclogites, DGrt/Omp∼0.1-0.2, but decreases slightly at high pressure. Based on the mineral proportions of the eclogites, we estimate bulk-rock water content in the eclogites ranging from 3070 to 300 ppm H2O (by weight). Although hydrous minerals are absent in the diamond-grade eclogite (∼60 kbar and ∼1000 °C), trace amounts of water are incorporated in the nominally anhydrous minerals such as omphacite and garnet. The presence of significant water in these minerals implies that the subducting oceanic crust can transport considerable amounts of water into the deep upper mantle beyond the stability of hydrous minerals. Such water may be stored in the deep upper mantle and have an important influence on dynamics in the Earth's interior. © 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.lithos.2005.06.006

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DOI： 10.1016/j.ijrmms.2005.06.006

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We investigate the conditions of hydrothermal alteration occurring along an active, seismogenic normal fault dipping <30° in the Moresby rift (Woodlark basin, Papua New Guinea). Petrological and fluid inclusion studies were conducted in the samples recovered from the Ocean Drilling Program leg 180 that cored the footwall, scarp, and hanging wall of the fault. Chemical analyses of the thermodependent Si-Al substitutions in chlorites show that synrift alteration is coeval with a temperature rise from 200°C to 300°C in the footwall of the detachment, whereas no thermal event is recorded in the hanging wall. In the same samples, fluid inclusions indicate that footwall rocks followed an isothermal exhumation path from 5-7 km to the subsurface. Taken together, the results strongly suggest that the +100°C temperature rise results from the upward migration of H2O-NaCl fluids expelled by dehydrating metamorphic rocks from the lower crust. Fluid release began with the onset of detachment faulting and is still actively occurring nowadays. The fact that low-angle earthquakes also occur now at 5 - 7 km along the fault suggests that the dehydration of the metamorphic rocks and the subsequent circulation of hot hydrothermal fluids may be responsible for the weakening of the middle crust and the formation of a detachment in the Moresby rift. Copyright 2005 by the American Geophysical Union.

DOI： 10.1029/2005GC001112

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Language：English   Publishing type：Research paper (scientific journal)  

In situ high-temperature visible microspectroscopy has been developed in order to study color change kinetics of volcanic materials. Olivine thin sections put on a synthetic alumina plate are heated on a heating stage at 600-800 degrees C under a visible microspectroscope. Changes in visible absorption spectra are monitored every 60 s for 5 hours. The obtained high-temperature visible spectra showed a gradual increase with time in absorbance in the shorter wavelength region (400-600 nm). The 430 nm absorbance (ligand field transition of Fe3+ increased more with time at higher temperatures. Assuming diffusional transport in plane sheets, apparent diffusion coefficients were determined at temperatures of 600-800 degrees C. The activation energy for this diffusion in olivine is 208 +/- 17 kJ/mol. This activation energy value is similar to those for the metal vacancy diffusion in olivine. This newly developed in situ high-temperature visible microspectroscopy can provide kinetic measurements of visible spectral change of materials at high temperatures such as volcanic materials.

DOI： 10.1366/000370205774783205

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The diffusivity anisotropy of ions through rock pore water was evaluated quantitatively by through-diffusion experiments on a rhyolite rock having anisotropic pore structure. The rhyolite has planar flow structure with elongated pore shapes to the flow direction (X-Y plane). Diffusion coefficients of K+ ions for the direction perpendicular to this flow structure (Z-direction) were about 5-9 times smaller than those for the orthogonal parallel directions (X- and Y-direction). Pore geometrical analyses on backscattered electron microscopic images indicated that the pore length ratios among the X-, Y-, and Z-direction were roughly 2: 2: 1. This shorter pore length for the Z-direction appears to reduce pore connectivity, causing larger tortuosity and smaller diffusivity for this direction. This diffusivity anisotropy needs to be taken into account for precise modeling of diffusion-limited geological processes such as contaminant transport and rock deformation. © 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.enggeo.2005.07.002

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To evaluate the behavior of iron during weathering, colors of four rhyolites with different degrees of weathering (eruption ages: 1.1, 1.8, 26, and 52 ka) were studied. Because the initial chemical compositions of the four lavas were similar to one another, it is considered that the four lavas had similar whitish color at the time of eruption. However, at present more weathered lavas have more yellow-brownish color, indicating the formation of iron (hydr)oxides or Fe-bearing clays. In order to characterize those weathering products, spectro-colorimetry and differential dissolution method were combined. The colors of 1.1- and 1.8-ka lavas are close to the color of ferrihydrite whereas those of 26- and 52-ka lavas approach to the color of goethite. This indicates that the initial stage of weathering is dominated by the formation of ferrihydrite and with increasing weathering the transformation from ferrihydrite to goethite proceeds. It is estimated from the change of rock color that the half-life for the transformation reaction of ferrihydrite to goethite in the field is >1100 years, which is at least 80 times longer than previously reported values based on laboratory experiments. The presence of impurities such as Si and Al in ferrihydrite can be a possible origin for retarding the transformation rate in the field. © 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.chemgeo.2005.03.005

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Change in permeability during vesiculation has been measured for vesiculated products from decompression experiments. The permeabilities of the experimental products are less than 10-15.5 m2 at vesicularity less than 45 vol %, and increase by about 2 orders of magnitude with the vesicularity increase from 45 to 80 vol %. The permeability-vesicularity relationship of the experimental products is quite different from those obtained for natural eruptive materials by previous measurements, which reported a dramatic increase in permeability from 10-15.5 to 10-13 m2 with vesicularity increase from 2 to 40 vol %. The quenched experimental products can be considered as snapshots in vesiculating magma during decompression. Therefore, the permeability variation in vesiculating magma is close to that obtained from the experiments than that obtained from natural eruptive materials, because the latter has experienced complex deformation in the late stages of eruption. Copyright 2005 by the American Geophysical Union.

DOI： 10.1029/2005GL022491

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The rate of numerous diagenetic, deformation and metamorphic processes in crustal rock systems ultimately depends on the structure and diffusive properties of water-bearing grain boundaries. We present the first in-situ spectroscopic study of the nature of aqueous films present in mineral interfaces undergoing stress-induced dissolution or 'pressure solution'. Using infrared micro-spectroscopy, we show that during active pressure dissolution of the (111) plane of halite (NaCl) against a CaF2 plate, the confined intercrystalline liquid has an average thickness of 85-185 nm and occupies a rough, non-equilibrium grain boundary structure. The hydrogen bonding of the water within the grain boundary film is modified due to increased polymerization towards ice-like (hard) water. Simultaneous pressure solution rate measurements show that diffusion within the grain boundary fluid is about one order of magnitude slower than in bulk solution. During active pressure solution of the (100) plane of halite, a similar non-equilibrium grain boundary structure develops but the average thickness of the confined water film is only ∼40 nm and no evidence is found for modification of the hydrogen bonding of the water. The difference in hydrogen bonding between the two orientations studied is attributed to differences in surface charge distribution on the (111) and neutral (100) interfaces in NaCl. The difference in mean film thickness is attributed to differences in crystallographically controlled roughness of the dissolving NaCl Surface. If similar grain boundary thickness and diffusivity effects occur in other rock forming minerals, pressure solution in such systems will tend to be interface reaction controlled and may be capable of producing significant seismic anisotropy. © 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.epsl.2004.12.030

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In order to revisit the kinetics of amino acid transformation in the chemical evolution, a series of hydrothermal experiments has been conducted for threonine (Thr) solution. Thr transformed into glycine (Gly) and other products including peptides and polymers at 121 to 160°C. The Thr → Gly decomposition rate (k1 ) is different from apparent Thr decreasing rate (k), because of the presence of other side reactions. Copyright © 2005 The Chemical Society of Japan.

DOI： 10.1246/cl.2005.158

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We determined near-infrared (NIR) molar absorptivities of hydroxyl group (4500 cm-1) and molecular water (5230 cm-1) in rhyolitic glasses at room temperature and at high temperature, 400-600 °C. Five rhyolitic glasses with 0.5-2.8 wt% total water were analyzed by FT-IR microspectroscopy at room temperature and at 50 °C intervals in the range of 400 to 600 °C using a heating stage. The total water contents in the rhyolitic glasses were measured by Karl-Fischer titration. Based on these data, the linear molar absorptivities of the 4500 and 5230 cm-1 bands at room temperature were determined to be 1.42 ± 0.12 and 1.75 ± 0.08 L/mol-cm, respectively. The integral molar absorptivities obtained are 285 ± 24 and 239 ± 11 L/mol-cm2 for the 4500 and 5230 cm-1 bands, respectively. These values can be used to determine the concentrations of hydroxyl group and molecular water in rhyolitic glass with 0.5-2.8 wt% total water at room temperature. The experimental results at high temperature show that the linear and integral molar absorptivities of the 4500 cm-1 band at 400-600 °C generally remain within 6% of the values at room temperature. On the other hand, the linear and integral molar absorptivities of the 5230 cm-1 band systematically decrease with increasing temperature in the ranges of 400 to 600 °C. These high-temperature molar absorptivities are useful for evaluating the water speciation in rhyolitic glass by in situ high-temperature IR microspectroscopy.

DOI： 10.2138/am.2005.1740

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Language：Japanese   Publisher：Japan Society of Engineering Geology  

Recent molecular dynamics simulations and spectroscopic approaches indicated that water molecules confined in nanometre scale has a constrained structure with shorter hydrogen bond distances. In order to verify a hypothesis that ionic diffusivity in rocks should be affected by the constrained molecule structure of water in nanopore, we measured the effective diffusion coefficients of iodide ion in rocks by through-diffusion experiments. We also studied the quantitative relationship between the diffusion coefficients and the pore structures. Most of effective diffusion coefficients for rocks can be explained by the power law with effective porosity, while those of the samples involving abundant nanopores were much lower than this relation. By an assumption of the power law between effective porosity and tortuosity, the ionic diffusivity through nanopore water can be estimated. The value is about one order lower than the diffusivity in &ldquo;free&rdquo; pure water, and relatively lower with smaller pore size. The similar effect has been suggested by permeability modeling with the consideration of the constrained molecule structure of water in nanopore. This consideration can be important for the quantitative estimation of mass transport properties through rocks.

DOI： 10.5110/jjseg.45.118

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We measured three-dimensional shape of a specimen of calcareous nannofossil by using an atomic force microscope (AFM), and traced its change during an aqueous dissolution experiment. Some numerical values are calculated to characterize the shape changes of the specimen upon dissolution; volume, surface area, and roughness of the specimen decreased by the dissolution. The present AFM method is expected to study quantitatively possible changes in calcareous nannofossil assemblage due to different dissolution rates for different fossil forms. Copyright 2004 by the American Geophysical Union.

DOI： 10.1029/2004GL020416

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The dehydration rate of hydrous rhyolitic glasses at 475-875°C was measured by in situ infrared (IR) spectroscopy in order to determine the diffusion coefficient of water in rhyolitic glasses. The IR spectra of glass thin sections were obtained at 90-s intervals during 90 min at high temperatures, and the change in absorbance at 3550 cm-1 corresponding to total water was monitored. The diffusion coefficients obtained from dehydration rates of the rhyolitic glasses are considered to be averaged value over the water-concentration profile in the sample. The averaged apparent diffusion coefficients increase with the initial total water content from 0.20 μm2 s-1 for 0.7 wt% to 0.37 μm2 s-1 for 2.8 wt% at 700°C. The apparent activation energy for the diffusion of total water decreases with increasing initial water content from 112 ± 6 kJ mol-1 for 0.7 wt% to 60 ± 17 kJ mo1-1 for 4.1 wt%. Assuming a linear relation between the diffusion coefficient of total water and the total water content, the diffusion coefficients at each initial total water content were also determined. The diffusion coefficients of total water at the water contents of 0.7 and 1.9 wt% and at 0.1 MPa were best fitted by In D = [(12.9 ± 0.8) - (111 500 ± 6400)/RT] and In D = [(10.6 ± 0.4) - (86 800 ± 2800)/RT], respectively, and are in agreement with previous data (D in μm2 s-1, T in K). The present in situ IR dehydration experiment is a rapid and effective method for the determination of water diffusivity at high temperatures. © Springer-Verlag 2004.

DOI： 10.1007/s00269-004-0383-1

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OH structure of metamorphic fluids has been studied by high temperature infrared (IR) microspectroscopy on natural fluid inclusions contained in quartz veins, over the temperature range 25-370 °C. Blueschist-facies veins from Tinos island core complex (Cyclades, Greece) display H2O-NaCl-CaCl2-CO2 inclusions whereas greenschist-facies veins contain H2O-NaCl ± CO2 inclusions. From 25 to 370 °C, peak positions of OH stretching IR absorption bands increase quasilinearly with slopes of 0.25 and 0.50 cm-1 °C-1 for inclusions trapped under blueschist and greenschist conditions, respectively. Extrapolation to 400 °C yield peak positions of 3,475 cm-1 for blueschist inclusions and 3,585 cm-1 for greenschist inclusions. Because the smaller wave number indicates the shorter hydrogen-bond distance between water molecules, fluids involved in the greenschist event have a 'loose' structure compared with blueschist fluids. We suggest that these properties might correspond to a low wetting angle of fluids. This would explain the high mobility of aqueous fluids suggested by structural observation and stable isotope analysis. © Springer-Verlag 2003.

DOI： 10.1007/s00410-003-0531-5

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Water in majoritic garnet synthesized in the mid-oceanic ridge basalt (MORB) + H2O composition at 20 GPa and 1400-1500°C was measured by secondary ion mass spectrometry (SIMS) and infrared spectroscopy. We found that the majorite contains 1130 to 1250 ppm OH by weight. The infrared absorption band showed that incorporation of the hydroxyl in majorite is most likely due to the hydrogarnet substitution. Our results indicate that water can be transported into the mantle transition zone by nominally anhydrous minerals such as omphacite and majorite in the subducting basaltic crust. Such water may have great influences on the physical properties of slab in the transition zone.

DOI： 10.1029/2003GL018127

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We applied an X-ray computed tomography (CT) imaging method to study fluid advection in a laboratory permeameter in order to visualize the advecting fluid image during permeability testing under atmospheric pressure and to elucidate the relationship between fluid flow properties within fault-related rocks and their deformation mechanism. The X-ray CT images show high-resolution, three-dimensional fluid flow distribution in the fault-related rocks. A fault zone without grain cataclasis enables fluid flow, whereas cataclastic fault zones act as barriers. The fluid flow properties of the deformation bands are strongly dependent on the cataclastic fabrics. In sheared rock, including some cracks, only connected cracks can function as fluid conduits. The localized permeabilities along permeable fault zones and fractures, calculated using fluid front rates, are two orders higher than averaged bulk permeability derived from the pressure or volume difference between inflow and outflow in the permeameter. © 2003 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0013-7952(03)00074-7

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Two types of pallasites can be distinguished on the basis of the grain shape of olivine (rounded or angular). It has been suggested that these two types of textures resulted from different degrees of annealing at high temperature in the parent body. In order to characterize the kinetics of rounding of olivine grains in an Fe-Ni matrix, we carried out a series of annealing experiments using a mixture of olivine and Fe-Ni powder. We were able to reproduce, at a miniature scale, the range of textures in pallasites. The rate of rounding was rapid enough to be observed and measured at the scale of a few micrometers to 20 μm, even though the experiments were performed below the solidus of the Fe-Ni metal. For instance, grains ≈14 μm in diameter became nearly spherical within 7 days at 1400°C. For the morphological analysis of olivine grains, we used two independent techniques: the "critical diameter method" and the "Gaussian diffusion-resample method," a new technique specially developed for our study. Both techniques indicate that the rounding time scale is proportional to the cube of the grain size and that morphological adjustments in our experiments occured by volume diffusion in the olivine lattice, not by surface diffusion along the olivine-metal boundaries. We used our experimental data to estimate the time scales required for the development of olivine-metal textures in natural pallasites. We determined that small scale rounding of olivine grains in a solid metal matrix can be produced within relatively short time intervals: ≈100 years to produce rounded olivine grains 0.1 mm in radius at 1300-1400°C.

DOI： 10.1111/j.1945-5100.2003.tb00278.x

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Language：English   Publishing type：Research paper (scientific journal)  

The attenuated total reflectance infrared (ATR-IR) spectra of several aqueous solutions have been measured by using a newly developed heatable rod-type ATR cell. The OH stretching bands showed systematic change with increasing solute concentrations and these changes can be explained by four different OH components based on curve-fitting results. NaCl solutions show longer H-bond distance character, while carbonate solutions present shorter ones. The Na2CO3 1 M solution conserves this shorter H-bond nature up to 100 degrees C. On the other hand, the loose nature of NaCl solutions becomes less pronounced at higher temperatures because of the dissociation of pure water clusters. These in situ observations of water structures are generally in agreement with the expected nature of fluids within the earth.

DOI： 10.1366/000370203321558173

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Clinopyroxenes in eclogites from the deep subducted crust in the Kokchetav, Kazakhstan, ultra-high-pressure metamorphic terrane were found by infrared spectroscopy to contain up to 3020 ppm OH. These rocks were recrystallized at pressures over 60 kbar and temperatures over 1000 °C, where no hydrous minerals are stable. Infrared spectra of the clinopyroxenes show three hydroxyl absorption bands in the regions 3440-3460 cm-1, 3500-3530 cm-1, and 3600-3625 cm-1. The hydroxyl absorbance increases with recrystallization pressure of the eclogites and with vacancy concentration in the pyroxene structure (Ca-Eskola component). Clinopyroxenes represent about 40-50 vol% of eclogites, such that the bulk eclogites contain approximately 1300 ppm hydroxyl at depths greater than 150 km. Thus, subducted oceanic crust can transport trace amounts of H2O into the upper mantle, even in the absence of nominally hydrous minerals.

DOI： 10.2138/am-2003-0126

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Molar absorptivity of the infrared (IR) fundamental OH-stretching vibration band at 3550 cm-1 was determined for rhyolitic glasses. Five obsidian samples, unheated and heated at 500-700°C using an internally heated pressure vessel, were used to evaluate the dependence of the molar absorptivity and final quenched H2O speciation on H2O contents and temperature. Water contents of the obsidians were measured by Karl-Fischer titration first, then the amount of unextracted H2O was calibrated by IR spectroscopy and a conventional vacuum extraction method. Total H2O contents of the obsidians were determined to be 0.24-1.25 wt%. IR spectra of the unheated and heated obsidian samples were obtained using an FT-IR microspectrometer. We determined the molar absorptivity for the 3550 cm-1 band to be 75 ± 4 L/mol/cm without significant dependence on the H2O contents and heating temperature. This value can be used to determine precise H2O contents up to 1.25 wt% in rhyolitic volcanic glasses.

DOI： 10.2138/am-2003-11-1204

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DOI： 10.1029/2003GL018127

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Faults profoundly affect patterns and rates of fluid flow and solute transport in the geological environment. They may act as conduits, barriers or combined conduit-barrier systems. In order to elucidate the relationship between fluid flow properties and deformation mechanisms of fault-related rocks, we applied X-ray CT during laboratory permeameter measurements for direct imaging of fluid flow during permeability testing. A KI solution, which has high X-ray attenuation values, was used as a contrast medium for the advection imaging. Three-dimensional fluid flow distributions were measured for the studied fault-related rocks. Fault zones characterized by independent particulate flow as deformation mechanism act as conduits for fluid flow, whereas cataclastic fault zones act as barriers.

DOI： 10.1144/GSL.SP.2003.215.01.10

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Language：Japanese   Publisher：The Geological Society of Japan  

DOI： 10.14863/geosocabst.2002.0_168_1

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In order to investigate the effects of melt movement on material transport, dissolution and crystal growth in partially molten rock systems, a new apparatus was designed to move partial melt. Spherical specimens with low degrees of melting (less than 40 vol%) were rolled in a PtRh crucible rotating at 240 rpm in an electric furnace. Melt movement in this rolling experiment was confirmed by the displacement of Au powder added to the partially molten natural dacite. A partial melt movement of about 200 μm/h was observed in the rolling experiment. Element transport in the melt was traced using a Ni foil placed in the centre of the spherical dacite specimens. The apparent diffusion coefficient of Ni in the rolling experiment (1 x 10-12 m2/s) was one order of magnitude larger than the diffusion coefficient in the static experiment (1 x 10-13 m2/s). An increase of the dissolution rate of crystals of ~ 20% was observed under these advective conditions. The calculated dissolution rates using diffusion coefficients and the thicknesses of compositional boundary layers in melt showed good agreement with the observed dissolution rates. This suggests that dissolution in the present study was transport-controlled and was enhanced by rolling. Furthermore, an increase in crystal growth rate was observed in an isothermal experiment using a partially molten synthetic pyroxene solid solution. These results indicate that the kinetics of dissolution and the growth of crystals are influenced by melt movement in partially molten rock systems in which advective material transport is larger than material transport resulting solely from molecular diffusion.

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1H nuclear magnetic resonance (NMR) imaging was performed for the measurement of self-diffusion coefficients of water molecules (1H2O) in smectite. We measured two smectite samples (saponite and montmorillonite) with 96.6 wt.% of water at 23.8°C. A stimulated echo imaging sequence with magnetic field gradient pulses for the diffusion measurement was applied to the samples at a static magnetic field of 2.35 T. Eight NMR images were obtained with systematically changing the strength of field gradient pulses. The statistics of 225 diffusion data for each sample showed that the average diffusion coefficient was 2.06 × 10-9 m2/s for saponite and 1.52 × 10-9 m2/s for montmorillonite. The standard deviation was 0.02 × 10-9 m2/s for saponite and 0.05 × 10-9 m2/s for montmorillonite. The measurement time for the eight NMR images was 2.8 h, which is much shorter than that for conventional methods. Therefore, NMR imaging is suitable for the quick measurement of water diffusion in clay. ©1999 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0169-1317(98)00049-0

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The nature of OH species in natural clear quartz was investigated by means of in-situ IR measurements over the temperature range -185 to 1000 °C. Reversible thermal behavior of OH species was examined for a sample pre-heated to 1000 °C for 1 hour. At room temperature, the IR spectrum of the quartz sample examined includes an intense absorption peak at 3379 cm-1 which has been assigned to an OH stretching vibration associated with Al substituting for Si (OH(Al)). The major spectral changes of the OH(Al) bond involve a systematic shift of its peak position and a decrease in its integral absorbance with temperature. A quasi-linear increase of the peak position from -185 to 400 °C is interpreted to be due to the change in the vibrational frequency of OH(Al) with hydrogen bond (H bond) distance. At higher temperatures, the IR frequency shows only a slight change, indicating a small influence of the H bond. On the other hand, the gradual decrease of the integral absorbance of OH(Al) with temperature indicates a decrease of this defect's molar absorptivity without any reduction in defect concentration. This is interpreted to result from a decrease in dipole moment of OH(Al) with temperature. A sudden shift of the vibrational frequency from 3396 to 3386 cm-1 between 550 and 560 °C and a constant value of the integral absorbance from 535 to 570 °C were considered to be related to the change in H bond distance during the structural transformation of α-quartz to its β-form. The local environment of OH(Al) begins to change at temperatures below 570 °C, where the crystallographic α-β transition occurs.

DOI： 10.1007/s002690050180

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The effects of neodymium (Nd) on the transformation of ferrihydrite to iron oxides was studied. The possible isomorphous substitution of Nd3+ for Fe3+ in iron oxides was examined also. Nd was used as an inactive substitute of trivalent radioactive actinide elements. Hydrolysis of ferric nitrate solution containing 0-30 mole % of Nd formed Nd, Fe-rich ferrihydrite as initial precipitates, which were poorly crystalline. Aging of the Nd-containing ferrihydrite in 0.3 M OH- at 40°C and at pH 9.2 at 70°C formed Nd-free goethite and Nd-substituted hematite. The abundance of these crystalline phases was related to Nd in the parent solutions. Phase abundance, unit-cell parameters, and peak width were estimated by use of the Rietveld method.

DOI： 10.1346/CCMN.1999.0470609

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NMR (Nuclear Magnetic Resonance) of 1H is applied for the first time to the three-dimensional imaging of hydrogen-bearing samples (stilbite, agate, and enhydros) from geothermal fields. The spin-spin relaxation time of the nuclei of 1H in hydrous minerals is very short, so that it has been difficult to detect NMR signals with a high S/N ratio. This technical problem has been solved by newly developed probeheads and pulse sequences, so that clear images of 1H in stilbite, agate, and enhydros can now be obtained. For example, 1H in an enhydros sample (about 5 cm in diameter) is successfully imaged at a resolution of 0.31 mm. NMR imaging is nondestructive and automatic and is therefore a promising instrument for the rapid acquisition of data on the three-dimensional distribution of water and hydrous minerals in rock samples from geothermal fields. © 1998 CNR. Published by Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0375-6505(97)00029-1

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Language：Japanese   Publisher：The Geological Society of Japan  

DOI： 10.14863/geosocabst.1998.0_P082

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The hydrogen isotopic composition of hornblende in volcanic rocks has potential to indicate processes such as degassing of a magma reservoir, as well as the origin of magmatic water. However, during eruption and high-temperature interaction with air, the isotope composition of hornblende can be altered. In order to establish criteria to select natural hornblende that preserves magmatic hydrogen isotopic ratios, hydrogen isotopic composition (δD), water contents, and colors of hornblendes were measured. A series of heating experiments on natural green hornblendes was conducted in air and under vacuum up to 1000°C. There observed a negative relationship between the intensity of redness (a*) and water content among heated hornblendes in air and under vacuum, as well as natural samples from several Quaternary volcanos in Japan. Heating hornblende results in a significant increase in δD value that can be explained by a Rayleigh distillation (simultaneous degassing without hydrogen isotopic exchange between the gas and the mineral) model involving degassing of both H2O and H2. According to the model, maximum fractionation occurs when hornblende dehydrates only by H2 degassing. Application of the model indicates that hornblendes in pumice fragments from Plinian eruptions are most representative of the δD of pre-eruptive magma. In contrast, the δD values of minerals from lava flows, lava domes, or even from thick pumice flow deposits may have suffered from 1) hydrogen isotopic fractionation by mineral dehydration, and/or 2) isotopic reequilibration with degassing magma during eruption stage and during cooling stage after the emplacement.

DOI： 10.2343/geochemj.32.33

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Hydrothermal hydration of silica glass was experimentally studied with pure water at temperatures of 400-500°C and pressures of 40-96 MPa. The dissolution of silica glass occurred at nearly constant rates based on the weight loss and the hydrated surface layers have optical anisotropy. The thickness of the hydration layer increased gradually during the initial stage of the reaction and reached a steady state thickness (0.1 mm) after tens of hours. Concentration-depth profiles of both OH and H2O species in the hydration layer were obtained using microscopic Fourier transform infrared spectroscopy (micro FT-IR). The concentration of the OH group was 0.4-1.3 wt% and that of H2O was about one third of the OH group near the surface. These concentrations decreased exponentially from the surface of the silica glass inward, indicating diffusion-related processes. Overall reaction rates are interpreted to be determined by diffusion of water in the hydration layer. The diffusion coefficients are estimated to be 10-15-10-14 m2/s and exhibit positive correlations with pressure and temperature. The activation energy was approximately 60 kJ/mol. Copyright © 1997 Elsevier Science Ltd.

DOI： 10.1016/S0016-7037(96)00406-1

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A series of in-situ high temperature infrared (IR) measurements of water in an agate sample and in a milky quartz has been conducted in order to understand the nature of water in silica at high temperatures (50-700 °C) and the dehydration behavior. IR absorption bands of water molecules trapped in the milky quartz showed a systematic decrease in intensities and a shift from 3425 cm-1 at 50°C toward 3590 cm-1 at 700 °C without any loss of water. This indicates a change in IR absorption coefficients corresponding to different polymeric states of water at different temperatures. The broad 3430 cm-1 band in the agate sample also showed a systematic decrease in IR intensity and a band shift toward higher frequency with increasing temperature ( ∼ 700 °C). This indicates that the agate sample also contains fluid inclusion-like water. For this agate sample, a dehydration of loosely hydrogen-bonded molecular water occurred at lower temperatures (<200 °C). At higher temperatures (>400 °C), sharp bands around 3660 and 3725 cm-1 (3740 cm-1 at 50 °C) due to surface silanols, appeared. This indicates dehydration of H2O molecules that are hydrogen bonded to surface silanols. SiOH species in the agate are divided into three groups, namely SiOH group located at structural defects, surface silanols hydrogen bonded to each other and free surface silanols. Former two dehydrate below 700 °C and the dehydration rate of the SiOH at structural defects is faster than the other. IR spectra show that SiOH species decrease continuously even after the dehydration of most of H2O molecules. All these results provide realistic bases for the change in physicochemical states of different OH species in silica at high temperatures.

DOI： 10.1007/s002690050018

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Language：Japanese  

J-GLOBAL

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Infrared microspectroscopy has been applied to thin sections of various deformed and metamorphosed rocks in order to investigate water content of quartz in these rocks. The broad IR band absorbance around 3400 cm-1 probably due to fluid-inclusion molecular water (H2O) was used to calculate water contents. Deformed granitic rocks from the Yanazawa-Kamimura area near the Median Tectonic Line (MTL) showed an increase of water content in quartz from about 300 ppm to 2500 ppm toward the MTL with increasing degree of deformation. Metacherts from Sambagawa metamorphic rocks (Asemigawa route) showed a systematic decrease of water content in quartz from about 1000 ppm to 200 ppm with increasing metamorphic degree from chlorite, garnet, albite-biotite to oligoclase-biotite zones. An Archaean metachert from the Napier Complex (granulite facies) has only 40 ppm water. Comparing this with an Inuyama unmetamorphosed chert sample having water contents of 3500 to 7000 ppm (a starting point of metamorphism), the systematic decrease of water in quartz with increasing metamorphic grade may extend from unmetamorphosed cherts to the highest-grade metacherts. Water contents in high-pressure metamorphic rocks in Japan are mostly of the order of 500 ppm (300-700 ppm), except for those from Kurosegawa with a water content as high as 1700 ppm. These results represent an exploratory analysis of intragranular water contents in quartz in various deformed and metamorphosed rocks. Further micro FT-IR studies of the distribution of water in crustal rocks will provide a quantitative basis for examining the geochemical cycle of water in the earth's crust. © 1995.

DOI： 10.1016/0040-1951(94)00239-6

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A systematic treatment of diffusion of ions in rock pore water is presented in order to provide data suitable for quantitatively addressing water-rock interaction problems including the influence of fluids on rock deformation. Diffusivity of ions in water-saturated, high-porosity sediments is primarily controlled by total porosity øtot and grain size. Diffusivity of ions in water-saturated, medium-porosity rocks (øtot = 0.005 to 0.5) is mainly controlled by the transport porosity øtra (> 5 nm), but is influenced by the tortuosity difference between fast pathways through interconnected micropores and slow pathways including nanopores (less than 25 nm). The effective diffusivity De vs. øtot relations obtained are potentially useful for the prediction of diffusion coefficients in rocks and also their time-dependence during water-rock interactions. Based on the above and literature data, the value ranges at 25°C of "pore-water diffusion" coefficients (Dpw) and of "grain-boundary diffusion" coefficients (Dgb) are evaluated. Comparison of these with recent higher temperature data suggests low activation energies estimated for both Dpw and Dgb (15 kJ mol-1). Representative Dgb value trends thus obtained yield "wet" grain-boundary diffusion coefficients Dgb of the order of 10-14 m2 s-1 at 150-350°C. An example calculation of strain rates in fluid-assisted rock deformation such as pressure solution is given based on the method of Shimizu using the above Dgb values. The strain rates at 350°C with typical grain size (d = 0.1 mm), differential stress (σ = 100 MPa) and typical grain-boundary width of about 1-10 nm are estimated to be very fast around 10-11 to 10-9 s-1 via diffusion through "wetted" grain boundaries. Very slow strain rates of about 10-17 s-1 are estimated for "non-wetted" deformation. Wetting characteristics of grain boundaries and the nature of aqueous fluid films have a significant role in the enhancement of rock deformation, especially for low-porosity rocks. © 1995.

DOI： 10.1016/0040-1951(94)00234-Z

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The crystallization kinetics of goethite were studied colorimetrically under highly alkaline conditions (pH 10.1-12.2) at temperatures from 40° to 85°C. Color changes during crystallization from fresh precipitates, plotted on a*-b* colorimetric diagrams, were used to discriminate between pure goethite and mixtures of goethite and hematite. Only the b* value increased as goethite crystallization proceeded, and even a minor increase in the a* value revealed the existence of hematite. The rate of goethite crystallization, estimated from the b* value, could be modeled by a pseudo-first-order rate law. This rate depended both on pH and on temperature. Apparent activation energies for the reactions of 56.1 kJ/mol at pH 11.7 and 48.2 kJ/mol at pH 12.2 were estimated from Arrhenius plots. © 1994, The Clay Minerals Society.

DOI： 10.1346/CCMN.1994.0420213

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The hypothesized reaction mechanisms for U reduction by the dehydrogenation of hydroxyl groups and aliphatic hydrocarbonaceous moieties of lignite were verified by kinetic U reduction experiments using simple alcohols (1-octadecanol and 2-propanol) and aliphatic hydrocarbons (n-octacosane). The rate constants and activation energies for U reduction by these alcohols are similar to those obtained for U reduction by lignite. The rate-determining step for U reduction by both simple and natural organic matter is hypothesized to be controlled by oxygen diffusion through U oxides. The equilibria of the system lignite-aqueous uranyl have been used to calculate standard free energy changes ΔG° for lignite dehydrogenation. Their comparison with those for the dehydrogenation of simple organic molecules supports the proposed reactions thermodynamically. © 1992.

DOI： 10.1016/0146-6380(92)90009-M

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Colors of Madeira Abyssal Plain sediments, North East Atlantic were determined with a simple colorimeter and described in the second CIE 1976 color space (L*a*b* color space). L*a*b* values of the original sediment core and the powdered sediments vary sharply with depth and these variations were found to be due to changes in the contents of calcium carbonate, organic matter, iron and manganese. The vertical color profiles are essentially conserved after drying and powdering. These results suggest that this rapid measurement method with the colorimeter can be used in quantitative color determination of marine sediments aboardship. As a result of quantitative studies among L*a*b* values, calcium carbonate, organic carbon, iron and manganese contents of powdered sediment samples, the following conclusions were obtained: (1) L* value (psychometric lightness) is controlled by calcium carbonate for whitish color and by organic matter for blackish color. The redox fronts can be easily characterized by a sharp decrease in L* value; (2) a* value (psychometric red-green chromaticness) is controlled by iron for pelagic sediments, by manganese carbonate and iron oxide and hydroxide for calcareous turbidites and turbidite G and by pigments and iron(II)-bearing minerals for greenish and grayish turbidites; (3) b* value (psychometric yellow-blue chromaticness) is controlled by iron contents probably in the form of hydroxides for calcareous turbidites. © 1992.

DOI： 10.1016/0025-3227(92)90222-4

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DOI： 10.1016/0025-3227(92)90217-6

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Color variations from brown to yellow of synthesized goethite have been studied colorimetrically and spectroscopically. Goethite with various colors was synthesized at pH 13 and 40°C by varying the incubation time. Colorimetry revealed that the b* value (yellowish chroma) in L*a*b* color space was a quantitative indicator of color variations of the diluted samples. From UV-VIS-NIR spectra, the increase in the b* value was found to be caused by the increase in crystal field absorptions due to goethite formation around 500 nm. The b* value was a good indicator of the relative proportion of goethite in the precipitates including ferrihydrite. X-ray diffraction patterns and infrared spectra revealed that crystallization of goethite was associated with loss of water from the proto-ferrihydrite. © 1992, The Clay Minerals Society.

DOI： 10.1346/CCMN.1992.0400515

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Interaction between aqueous acid uranyl solutions and two lignite samples have been studied experimentally at temperatures from 20 to 250°C in order to elucidate the diagenetic evolution of uranium-lignite systems. For the Tertiary lignite from Arjuzanx, France, which is rich in carboxyl groups, fast removal of U from solution occurred already at room temperature by means of cation exchange. Uranyl species are observed by IR spectroscopy to be adsorbed to the lignite. IR spectra of organic moieties suggest the complexation of U by carboxyl groups. This uranyl-carboxyl compound appears to be decomposed thermally to demix uraninite (reduced U) following the decarboxylation of the lignite. In the case of Cretaceous lignite from Gardanne, France, which is poor in carboxyl groups, uranyl adsorption requires some heating and results in the formation of stable organo-uranyl compounds without ion exchange. These compounds seem to be an activated complex controlling the reaction rate in the reduction of uranyl into uraninite at higher temperatures. These experimental studies suggest that uranyl might be complexed by lignite without reduction at low temperature geological environments and the U reduction might occur under late diagenetic or hydrothermal conditions. © 1992.

DOI： 10.1016/0048-9697(92)90108-5

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The relation between dissolved uranium and humic substances in pore water of marine sediments was studied in three different marine environments (hemipelagic, pelagic, and Japan Trench sediments) off Hokkaido Island, Japan. Pore water samples were squeezed out from sediments collected by a box corere at these sites, and their UV-visible spectra, fluorescence emission spectra and uranium concentrations were measured. In hemipelagic sediments, a positive correlation between uranium content and fulvic acid content (fluorescence at 400 nm) in pore water was observed. In Japan Trench sediments, positive correlations between uranium content and absorbance at 280 and 320 nm of pore water are found. These results suggest that pore water uranium may be complexed with dissolved humic substances, especially fulvic acid in hemipelagic and Trench sites. © 1992.

DOI： 10.1016/0048-9697(92)90109-6

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：MATERIALS RESEARCH SOC  

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Language：Japanese   Publisher：Japan Association of Mineralogical Sciences  

The new trends of mineralogical sciences have been suggested with a special emphais on the development of in-situ characterization techniques such as microspectroscopy, the quantitative color description by colorimetry and the quantitative representation of forms and textures of the real rock and material systems. The systematic treatments of heterogeneous mineralogical kinetics including solid-liquid and solid-gas reactions, diffusion, phase transformation and rheology should also be advanced. The background of these new mineralogy depends on their academic environments and the education of younger generation. Young Mineralogist Organization (YMO) has been working since 5 years to provide a forum of communication and crossover of mineralogical people who are mentally young. In order to take over these interdisciplinary interactions into the academic societies themselves, the unity of 3 mineralogy related societies and their English journals should be envisaged.

DOI： 10.2465/gkk1952.21.293

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A convenient method has been developed for the determination of colors of wet and powdered marine sediments. The colors of the sediments are determined with a simple colorimeter and described in the second CIE 1976 color space {Lsab color space). This method can sensitively detect color differences impossible to detect by the naked eye for wet and powdered sediment samples. It generally gives standard deviations of about 3% for replicate determinations of Labk values for powdered samples of brown, dark brown, and greenish gray sediments, and less than 8% for wet black sediments. The color measurement of wet core samples on board the ship can be rapidly performed by this method, which is much more convenient and quantitative than the conventional visual color description using rock color chart. The effects of water content, grain size and oxidation artifact on color of sediments are also discussed. © 1991, GEOCHEMICAL SOCIETY OF JAPAN. All rights reserved.

DOI： 10.2343/geochemj.25.187

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Diffuse reflectance spectroscopy and colorimetry have been applied to study the colors of powdered granitic rocks with different degrees of weathering. As a result, FeO(OH) was considered to be the source of the yellow-brownish color of the weathered rock powders. FeO(OH) contents were determined by diffuse reflectance spectroscopy based on the Kubelka-Munk function and found to increase during weathering. The FeO(OH) contents can be hence taken as a quantitative indicator of the degree of weathering. © 1989, GEOCHEMICAL SOCIETY OF JAPAN. All rights reserved.

DOI： 10.2343/geochemj.23.75

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As a first step of the reaction path modeling of the long-term behavior of iron during water-rock interactions visible diffuse reflectance spectroscopy and infrared microspectroscopy have been applied to elucidate chemical forms of iron and water in granitic rocks. These spectroscopic methods revealed that at least a part of dissolved iron in groundwater is finally fixed in granitic rocks as ferric iron hydroxides or oxides. Their chemical forms depend on the geochemical environments: ferric iron hydroxides are precipitated around biotite during the weathering and goethite and hematite are preserved inside feldspars along the fracture after the hydrothermal alteration. The behaviors of iron during these natural processes are expected to provide bases for the evaluation of long-term behaviors of certain radionuclides such as Am.

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Fourier transform infrared microspectroscopy (Micro FT-IR) has been applied to minerals to analyze hydrous microphases. Spectra interpretation and mapping analysis of a thin section of altered granitic rock can give us information on the chemical states of hydrous species and their spatial distribu-tion, respectively, in an area as small as 10x10/µm. Micro FT-IR can be a powerful method of microscopical study of heterogeneous geochemical processes, such as water-rock interactions. © 1989, GEOCHEMICAL SOCIETY OF JAPAN. All rights reserved.

DOI： 10.2343/geochemj.23.57

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The reactivity of lignite towards soluble uranyl species in an aqueous medium has been investigated experimentally as a function of T (20-400oC). The fixation process starts near 45oC, with reduction beginning at approx 120oC, and leads to the formation of chemically and thermally stable organo-uranyl species. The reduction of free uranyl species is accompanied by a stoichiometric (2:1) liberation of protons into the medium; these protons originate from the organic matter which thus undergoes dehydrogenation, explaining the low hydrogen content of natural organic materials associated with U deposits. Alcoholic and aliphatic hydrocarbon groups are responsible for the reduction; the kinetics have been studied at 180, 190 and 200oC and, when extrapolated to 20oC, show that reduction can be a crucial process in the geochemical behaviour of U especially in the thermal conditions in which sedimentary basins evolve. -R.A.H.

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Language：French   Publishing type：Research paper (scientific journal)   Publisher：MASSON EDITEUR  

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Interactions between lignite and soluble uranyl species have been investigated experimentally at different temperatures from 20° to 400°C. Fixation of uranyl species by lignite (45° to 250°C) and their reduction to uraninite (120° to 400°C) were observed. The fixation of uranyl species by lignite results in the formation of stable organo-uranyl compounds. The reduction of uranyl species by lignite results in a stoichiometric liberation of H+ in the solution medium and in a dehydrogenation of lignite. This dehydrogenation can be attributed to two different processes. The first is an oxidation of alcohol functional groups into aldehyde or ketone functions accompanied by a simultaneous reduction of uranyl species. The second is a dehydrogenation of hydrocarbonaceous aliphatic moieties induced by the uranium species. The molecular hydrogen produced during this process is subsequently used for an additional reduction of uranyl species. © 1984.

DOI： 10.1016/0016-7037(84)90228-X

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The behaviour of uranium is examined experimentally in the course of partial fusion of natural or synthetic granitic rocks. Uranium is soluble in the associated hydrothermal solutions containing chloride under oxidizing conditions, but it is not soluble in the same fluids under reducing conditions. -English summary

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The experimental study of the uranium-lignite association has been investigated at different temperatures from 20 t0 400oC. Fixation of uranyl species by the lignite (45 to 250oC) and reduction of them to uraninite (120 to 400oC) were observed. The reduction of uranium is accompanied by dehydrogenation of the lignite.-English summary

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Total pages：x, 233p   Language：Japanese  

CiNii Books

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Total pages：292p, 図版 [4] p   Language：Japanese  

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CiNii Books

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Language：Japanese   Publisher：The Physical Society of Japan  

DOI： 10.11316/jpsgaiyo.66.1.4.0_731_2

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Language：Japanese   Publisher：The Physical Society of Japan  

DOI： 10.11316/jpsgaiyo.66.1.4.0_731_1

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Language：Japanese   Publisher：Atomic Energy Society of Japan  

DOI： 10.11561/aesj.2011f.0.682.0

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Language：Japanese   Publisher：The Physical Society of Japan  

DOI： 10.11316/jpsgaiyo.65.2.4.0_672_1

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Language：Japanese   Publisher：The Physical Society of Japan  

DOI： 10.11316/jpsgaiyo.65.2.4.0_672_2

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：SPRINGER  

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：SPRINGER  

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Language：English   Publisher：JAPAN ASSOC MINERALOGICAL SCIENCES  

High temperature impedance spectra, up to 450 C, were measured for a microcrystalline quartz aggregate (chalcedony), which initially contained 0.3 wt% of liquid-like water (H2O) dispersed in grain boundaries and fluid inclusions together with 0.3 wt% of hydroxyl (Si-OH) in the crystal structure. Infrared spectra obtained after heating, showed dominant dehydration of liquid-like water, while much hydroxyl remained stable. Electrical conductivities before (wet) and after heating to 450 C (dry) gave linear Arrhenius relations with apparent activation energies of 11 +/- 1 kJ/mol for initial heating of the wet sample versus 32 +/- 3 kJ/mol for the subsequently dry sample. Compared with previously reported Arrhenius relations for alpha-quartz single crystals, our activation energies are much lower, and the absolute conductivities we obtained range from similar values to three orders of magnitude higher. We infer that the presence of grain boundaries and/or triple junctions containing liquid-like water greatly influences the electrical conductivity.

DOI： 10.2465/jmps.081022f

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

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Language：Japanese   Publisher：The Surface Science Society of Japan  

Physicochemical properties of thin film water on and between material surfaces have been reviewed. Infrared (IR) spectroscopy on thin film water sandwiched between various materials showed shifts of OH stretching vibration frequency maxima from 3400 cm^&minus;1 to about 3250 cm^&minus;1. These shifts vary with different materials, crystallographic orientations, film thickness (less than about 200 nm), dissolved ions and temperatures. The thin film water is supposed to have constrained structure close to ice and might have smaller diffusion coefficients and larger viscosity than the bulk liquid water. Standard molar volume, specific heat and entropy values for hydration water on some inorganic materials are different from these for the bulk liquid water and close to those for ice polymorphs. Sonic wave velocity measurements on a water-saturating rock suggest a larger P wave velocity for the thin film water than the value for bulk water. These structured thin water films with different properties from those of the bulk water can be present in the earth's interior and also in living materials such as cactus and human skin controlling dynamics of earth and life.

DOI： 10.1380/jsssj.30.140

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Language：Japanese   Publisher：Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)  

TANPOPO, dandelion, is the name of a grass whose seeds with floss are spread by the wind. We propose the analyses of interplanetary migration of microbes, organic compounds and meteoroids on Japan Experimental Module (JEM) of the International Space Station (ISS). Ultra low-density aerogel will be used to capture micrometeoroid and debris. Particles captured by aerogel will be used for several analyses after the initial inspection of the gel and tracks. Careful analysis of the tracks in the aerogel will provide the size and velocity dependence of debris flux. The particles will be analyzed for mineralogical, organic and microbiological characteristics. Aerogels are ready for production in Japan. Aerogels and trays are space proven.

DOI： 10.2322/tstj.7.Tk_49

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Language：Japanese  

CiNii Books

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J-GLOBAL

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CiNii Books

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Language：Japanese   Publisher：日本惑星科学会  

CiNii Books

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：METEORITICAL SOC  

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Publisher：GEOCHEMICAL SOCIETY OF JAPAN  

Cosmic dusts and carbonaceous chondrites are expected to have delivered life's raw materials to the early earth. Because these cosmic organics are very small, their in-situ characterization needs new generation of micro-spectroscopy. The development of infrared (IR) and Raman microscopic imaging spectroscopy enables rapid screening of the presence of organics in cosmic materials. We have been developing near-field infrared spectroscopy beyond the diffraction limit. These new micro-spectroscopic methods will enable measurements of small organic materials contained in cosmic materials returned from the space.

DOI： 10.14862/geochemproc.55.0.180.0

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Language：Japanese   Publisher：Japan Association of Mineralogical Sciences  

The aim of this study is to demonstrate the changes of electrical conductivity associated with dehydration of a microcrystalline quartz aggregate (chalcedony), an analogue material for crustal rocks with grain boundaries containing liquid-like water. This sample contains liquid-like water among grains of a few hundred nanometers and hydroxyl in quartz crystal structure. At the constant temperature of 250, 350 and 450&deg;C, high temperature impedance measurements were continuously performed by about 1 hour intervals, during 6, 6 and 3 days, respectively. At 350&deg;C the electrical conductivity increased from 5 &times; 10^-5 Sm^-1 to two orders of magnitude higher value. The liquid-like water content, determined by infrared spectroscopy, decreased from 0.3 to 0.1 wt% upon heating, while the hydroxyl content remained mostly unchanged.

DOI： 10.14824/jakoka.2008.0.97.0

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Publisher：GEOCHEMICAL SOCIETY OF JAPAN  

Attenuated total reflectance infrared (ATR-IR) spectroscopy was applied to investigate the dissociation states of amino acids adsorbed on mineral surfaces.First, in order to evaluate the relation between ATR-IR spectra and each dissociation states, pH-induced spectral changes of amino acids were measured and correlated with the thermodynamically calculated dissociation states of amino acids. This procedure yielded each calibration lines with good linearity, which were used for quantitative analysis of adsorbed amino acids. This analysis revealed that adsorbed amino acids are present on mineral surface as apparently different dissociation states compared to that in bulk solution.

DOI： 10.14862/geochemproc.55.0.353.0

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Language：Japanese   Publisher：Japan Association of Mineralogical Sciences  

Typical cyclosilicates, cordierite and beryl, form a channel which is a pipe-like cavity. It is known that two types of water molecules called type I and type II are trapped in the channel. Type I orients its H-H vector parallel to c-axis (channel direction). When a cation such as Li+ or Na+ locates near the water molecule, it reorients to become type II, so that its H-H vector is perpendicular to c-axis. High temperature and quenched room temperature infrared spectra were measured for natural cordierite and beryl. The stability and dehydration behavior of the both types of water molecule will be discussed by observing the peak shift and peak broadening. The changes of peak frequency of type II water can be explained by the change in coordination number to a cation.

DOI： 10.14824/jakoka.2008.0.106.0

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J-GLOBAL

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Language：Japanese  

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

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Language：Japanese   Publisher：大阪大学低温センター  

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Publisher：THE JAPANESE SOCIETY FOR PLANETARY SCIENCES  

Organic matter alteration on carbonaceous chondrite parent body was simulated under micro FT-IR with a heating stage. Leonardite (IHSS standard humic acid) and synthetic saponite were used as the macromolecular organics and the matrix mineral. These powdered samples were dispersed by MilliQ water then dropped on an CaF2 plate and dried. They were heated in the heating stage at room temperature to 600C by 10C/min in air, Ar gas and H2+CO2 gas mixture. IR spectra were collected at every 20C under the micro FT-IR. Aliphatic C-H increased from room temperature to approximately 250C then decreased. Aromatic C-H increased from room temperature to around 400-450C then decreased. Aliphatic C-H decreased faster and Aromatic C-H increased faster in Air than in Ar or H2+CO2. The decrease in aliphatic C-H of leonardite and the increase in aromatic C-H were slower with the presence of saponite than those of leonardite only.

DOI： 10.14909/jsps.2007f.0.137.0

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Language：Japanese   Publisher：The Geological Society of Japan  

DOI： 10.14863/geosocabst.2007.0.244.0

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Language：Japanese  

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Language：Japanese   Publisher：THE JAPANESE SOCIETY OF SNOW AND ICE  

DOI： 10.14850/jssi.2007.0.102.0

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：SPRINGER  

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Publisher：THE JAPANESE SOCIETY FOR PLANETARY SCIENCES  

Carbonaceous chondrites are known to contain a few wt. % organic matter whose majority consists of macromolecular organic compounds (e.g. Botta and Bada, 2002; Sephton, 2002). Minerals are suggested to have catalytic effects for the production and alteration processes of these organic materials (e.g. Wing and Bada, 1992; Kerridge, 1999). We conducted mapping measurements of Tagish Lake meteorite grains by Fourier Transform Infrared Micro-Spectroscopy (micro-FTIR) and Scanning Electron Microscopy and Energy Dispersion X-ray Spectrometry (SEM-EDS) for studying the distribution of minerals and organic matter. Tagish Lake was powdered and pressed between two pieces of Al discs to make the sample flat. The mapping area is 590 x 950 microns for micro-FTIR (Jasco IMV-4000 + FTIR-6200; resolution 12.5 microns) and SEM-EDS (JEOL JSM-5510LV + JED-2300). By the micro-FTIR mapping, heterogeneous distribution of aliphatic C-H and organic C-O was observed, and aliphatic C-H was distributed with phyllosilicate O-H. SEM-EDS elemental analysis revealed that aliphatic C-H rich portions were Mg rich and Fe, S poor. These results indicate that aliphatic C-H is coexisting with Mg-rich phyllosilicates.

DOI： 10.14909/jsps.2006f.0.108.0

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Publisher：GEOCHEMICAL SOCIETY OF JAPAN  

DOI： 10.14862/geochemproc.53.0.116.0

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Publisher：THE JAPANESE SOCIETY FOR PLANETARY SCIENCES  

Some Antarctic Micrometeorites (AMMs) were studied non-destructively by infrared (IR) microspectroscopy for characterizing organic and hydrous components in these particles. Their IR spectra showed absorption peaks of OH (molecular water) at 3400 cm−1, aliphatic carbonaceous components at 2960 cm−1 for CH3 and 2925 and 2860 cm−1 for CH2. By using peak height ratios of CH3/CH2 (2960 cm−1/2925 cm−1) and OH/CH2 (3400 cm−1/2925 cm−1), aliphatic and hydrous component characters of AMMs can be quantitatively investigated. The CH3/CH2 and OH/CH2 ratios of AMMs are ranging 0.6-0.9 and 1-3, respectively. These ratios of AMMs are smaller than those of carbonaceous chondrites. In order to study effects of heating, an AMM was heated in-situ under the IR microscope in atmosphere at temperatures from room temperature (RT) to 600˚C. The peak height ratio of CH3/CH2 remained mostly unchanged from RT to 210˚C and increased from 210˚C to 300˚C. The OH/CH2 ratio decreased from RT to 210˚C and then increased greatly from 210˚C to 300˚C. Effects of aqueous altaeration on micrometeorites are now being studied by hydrothermal experiments on simulated mineral-organic compounds.

DOI： 10.14909/jsps.2006f.0.109.0

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

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DOI： 10.14862/geochemproc.52.0.284.0

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Language：Japanese   Publisher：The Volcanological Society of Japan  

In order to measure permeabilities of small volcanic eruptive materials and experimental run products, we developed a new simple permeameter to measure gas permeabilities of millimeter-size samples. This permeameter can measure permeability in the wide range from 10^-17 to 10^-10m², with the precision within one order of magnitude. Nitrogen gas is used as a working gas. The permeability is calculated by using Darcy's law applied to results of steady state gas flow measurement at fixed pressure differences up to 1.5×10⁴Pa (ca. 0.15atm). The pressure difference is measured with the precision of 10Pa by a water column manometer. Gas flow rate is converted to water flow rate in an acrylic container and the water flow dripping from the container through the tube into a flask is monitored by an electric balance. We confirmed the accuracy in permeability measurement by measuring gas flow in a stainless capillary tube (15mm in length and 100μm in inner diameter). We carried out flow measurement with the pressure difference of 1.2×10² to 1.4×10⁴Pa at the flow rate of 3.5×10^-10 to 3.9×10^-8m³/s. Measured gas flow rate was compared with calculated flow rate, assuming that the gas flow in the capillary tube is Poiseuille flow. Although the difference between them becomes large for smaller flow rate than 10^-9m³, the discrepancy is within 0.25 log unit for the flow rate larger than 10^-10m³/s. Permeabilities of centimeter-size, four air-fall pumice and scoria measured by this permeameter are consistent with the permeability-vesicularity relationship obtained from pyroclastic materials by Klug and Cashman (1996). We measured permeabilities of nine samples of porous ceramics with varying dimensions from 1.3 to 8.3mm in length and from 5 to 78mm² in cross sectional area, which were cut from a homogeneous ceramic rod. Permeabilities of millimeter-size samples are consistent with those of ca. 1 centimeter-size samples, indicating that this permeameter can determine permeability for the millimeter-size samples. The permeameter can be easily assembled with commercially available components at a very low cost, and will be a useful tool to measure permeabilities of small volcanic eruptive materials and experimental run products.

DOI： 10.18940/kazan.50.1_1

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Language：Japanese   Publisher：The Volcanological Society of Japan  

DOI： 10.18940/vsj.2005.0_150

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Language：Japanese   Publisher：The Volcanological Society of Japan  

DOI： 10.18940/vsj.2005.0_25

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Language：Japanese   Publisher：海洋出版  

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

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DOI： 10.18940/vsj.2004.0_104

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Language：Japanese   Publisher：The Volcanological Society of Japan  

In order to study quantitatively color changes of basaltic scoria erupted at Takatsukayama, North-east Izu, Japan, the scoria colors were measured by spectro-colorimetry and described m the international standard color space(CIE L^* a^* b^*)The color values [a^* (red) and b^* (yellow) values]of Takatsukayama scoria cone increase from margin to center, indicating their color change from black to red. The bulk chemical compositions of scoria, including total Fe content, remain almost unchanged despite the color variations. 0n the other hand, the FeO(Fe²⁺) contents determined by the phenanthrolme method have a good linear relation with a^* values (red) of scoria. Under the optical microscope, the red parts are not found m the black scoria, whereas the red scoria have red parts m the groundmass and the olivine phenocryst. For dull red scoria, the red carts are observed only m the groundmass These indicate that red parts appear first m the groundmass and then in the olivine phenocryst. Visible and Raman microspectroscopy indicated the presence of hematite m these red Darts A series of heating experiments of the black scoria under an atmospheric condition at 500-1150℃ were conducted to simulate the color changes of Takatsukayama scoria. The heated scoria showed the increases in a^* and b^* values (i e. red coloring). The FeO(Fe²⁺) contents of the heated scoria had similar linear correlation with a^* values (red) as for natural ones. The presence of hematite was also found by visible and Raman microspectroscopy. These results imply that the increases in a^* and b^* values (red coloring) of Takatsukayama scoria can be explained by the high temperature oxidation of Fe²⁺, resulting m the formation of hematite first in the groundmass and then m the olivine phenocryst. Since the direction of the red coloring is oblique to the depositional sequences of the cone, the high temperature oxidation process might have occurred after the scoria deposition from the center of a heat source to the outer parts.

DOI： 10.18940/kazan.49.6_317

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Language：Japanese   Publisher：The Volcanological Society of Japan  

DOI： 10.18940/vsj.2004.0_174

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

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Language：Japanese   Publisher：The Geological Society of Japan  

DOI： 10.14863/geosocabst.2003.0_210_2

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

Water is found to be distributed mainly in grain boundaries in shallower parts of the earth (crust) by infrared microspectroscopy. Thin film water in grain boundaries might have an ice-like "harder" character than normal free liquid water. In deeper parts of the crust, with grain growth at higher temperatures, the decrease in water content and grain boundary width would result in disconnected "hard" water in grain boundaries with high viscosity and low permeability. This "hard" water might therefore be a possible origin of earthquakes. The chemistry (NaCl vs. CO_2) of water affects greatly the "hardness" of water and could control earth's dynamics. This paper review the geodynamics, which has been considered by macroscopic mechanical phenomena, with a new microscopic physicochemical point of view based on water structure.

DOI： 10.11316/butsuri1946.57.746

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Language：English   Publisher：ELSEVIER SCIENCE BV  

Infrared microspectroscopy reveals that liquid-like water is always present in polycrystalline quartz grains from low-grade metamorphic cherts and shale in the Chichibu Group and the Mikabu Greenrock Complex of the Kanto Mountains area. The water distribution in these rocks is heterogeneous and is related to rock textures. In the microcrystalline quartz, O-H species due possibly to Si-OH are generally present. The liquid-like water is also present at grain boundaries and/or in sub-micron fluid inclusions in the microcrystalline parts. On the other hand, in quartz grains larger than 20 μm in diameter within veins, only the liquid-like water is present, possibly as fluid inclusions trapped during quartz vein formation. In the microcrystalline cherty matrix of the metamorphic rocks, a general decrease in liquid-like water content is observed with increasing metamorphic grade, associated with an increase in grain size. Two representative grain shapes, a cube and a regular tetradecahedron (having 14 planes), are used to estimate the surface area between grains per unit volume with the grain size D (μm): 3/D for cubic and 2.37/ D for tetradecahedron. Grain boundary volumes were then calculated assuming grain boundary widths from 0.5 to 20 nm and normalized by unit volume of the rock. The measured IR data on low-grade metamorphic cherty rocks fall closely on these curves with grain boundary width of around 10 nm for the both models, assuming saturation of H2O at grain boundary. The observed decrease in water content with increase in grain size can be rigorously explained by the decrease in grain boundary volume per unit volume. These results suggest that liquid-like water occurs mainly between grain boundaries in the microcrystalline quartz of low-grade metamorphic rocks. Although this grain boundary water model is the first approximation and requires further details of quantitative grain boundary textures, the present model can provide a new approach to understand water distribution in polycrystalline rocks. © 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0009-2541(02)00022-0

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Language：Japanese   Publisher：The Geological Society of Japan  

DOI： 10.5575/geosoc.108.606

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Language：English   Publisher：ELSEVIER SCIENCE BV  

Infrared microspectroscopy reveals that liquid-like water is always present in polycrystalline quartz grains from low-grade metamorphic cherts and shale in the Chichibu Group and the Mikabu Greenrock Complex of the Kanto Mountains area. The water distribution in these rocks is heterogeneous and is related to rock textures. In the microcrystalline quartz, O-H species due possibly to Si-OH are generally present. The liquid-like water is also present at grain boundaries and/or in sub-micron fluid inclusions in the microcrystalline parts. On the other hand, in quartz grains larger than 20 mum in diameter within veins, only the liquid-like water is present, possibly as fluid inclusions trapped during quartz vein formation. In the microcrystalline cherty matrix of the metamorphic rocks, a general decrease in liquid-like water content is observed with increasing metamorphic grade, associated with an increase in grain size. Two representative grain shapes, a cube and a regular tetradecahedron (having 14 planes), are used to estimate the surface area between grains per unit volume with the grain size D (mum): 3/D for cubic and 2.37/D for tetradecahedron. Grain boundary volumes were then calculated assuming grain boundary widths from 0.5 to 20 nm and normalized by unit volume of the rock. The measured IR data on low-grade metamorphic cherty rocks fall closely on these curves with grain boundary width of around 10 nm for the both models, assuming saturation of H2O at grain boundary. The observed decrease in water content with increase in grain size can be rigorously explained by the decrease in grain boundary volume per unit volume. These results suggest that liquid-like water occurs mainly between grain boundaries in the microcrystalline quartz of low-grade metamorphic rocks. Although this grain boundary water model is the first approximation and requires further details of quantitative grain boundary textures, the present model can provide a new approach to understand water distribution in polycrystalline rocks. (C) 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0009-2541(02)00022-0

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Language：English   Publisher：SOC APPLIED SPECTROSCOPY  

In order to nondestructively characterize chemical forms of ferric hydroxides in weathered rock, charge-coupled device type visible microspectroscopy was applied to brown stains produced in weathered granite surfaces. The combination of visible microspectra and color parameters (a* and b*) was effective in examining chemical forms of ferric hydroxides in the analytical area. Color parameters in an a*-b* diagram of the brown stains, mostly lying between goethite and ferrihydrite trends, indicated that the brown stains contain ferrihydrite or hematite in addition to goethite. Similarity of the visible microspectra of the brown stains and their first derivatives to those of goethite or ferrihydrite suggests that goethite and/or ferrihydrite are the main weathering products of the granite. Occurrence of ferrihydrite as well as goethite in the brown stains implies that crystallization of ferrihydrite to goethite might be hindered during the granite weathering. This fact suggests the possibility of toxic metal retention in ferrihydrite by its long-term persistence during water-rock interactions at the earth's surface.

DOI： 10.1366/0003702021955222

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Language：English   Publisher：SOC APPLIED SPECTROSCOPY  

In order to nondestructively characterize chemical forms of ferric hydroxides in weathered rock, charge-coupled device type visible microspectroscopy was applied to brown stains produced in weathered granite surfaces. The combination of visible microspectra and color parameters (a* and b*) was effective in examining chemical forms of ferric hydroxides in the analytical area. Color parameters in an a*-b* diagram of the brown stains, mostly lying between goethite and ferrihydrite trends, indicated that the brown stains contain ferrihydrite or hematite in addition to goethite. Similarity of the visible microspectra of the brown stains and their first derivatives to those of goethite or ferrihydrite suggests that goethite and/or ferrihydrite are the main weathering products of the granite. Occurrence of ferrihydrite as well as goethite in the brown stains implies that crystallization of ferrihydrite to goethite might be hindered during the granite weathering. This fact suggests the possibility of toxic metal retention in ferrihydrite by its long-term persistence during water-rock interactions at the earth's surface.

DOI： 10.1366/0003702021955222

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Language：English   Publisher：AMER ASSOC ADVANCEMENT SCIENCE  

Secondary ion mass spectrometry measurements show that Earth's representative lower mantle minerals synthesized in a natural peridotitic composition can dissolve considerable amounts of hydrogen. Both MgSiO3-rich perovskite and magnesiowüstite contain about 0.2 weight percent (wt%) H2O, and CaSiO3-rich perovskite contains about 0.4 wt% H2O. The OH absorption bands in Mg-perovskite and magnesiowüstite were also confirmed with the use of infrared microspectroscopic measurements. Earth's lower mantle may store about five times more H2O than the oceans.

DOI： 10.1126/science.1065998

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Secondary ion mass spectrometry measurements show that Earth's representative lower mantle minerals synthesized in a natural peridotitic composition can dissolve considerable amounts of hydrogen. Both MgSiO3-rich perovskite and magnesiowüstite contain about 0.2 weight percent (wt%) H2O, and CaSiO3-rich perovskite contains about 0.4 wt% H2O. The OH absorption bands in Mg-perovskite and magnesiowüstite were also confirmed with the use of infrared microspectroscopic measurements. Earth's lower mantle may store about five times more H2O than the oceans.

DOI： 10.1126/science.1065998

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Language：Japanese   Publisher：Japan Association of Mineralogical Sciences  

At the earth's surface, divers organic-inorganic interactions are occurring and controlling the biogeochemical cycling. In this paper, we will review the experimental results on silica-organic interactions in aqueous solutions. The kinetics of dehydration-crystallization of hydrated amorphous silica into more crystalline forms during the diagenesis of siliceous marine sediments was studied and the influence of some biogenic organic compounds was evaluated. The transformation of amino acids on hydrous silica was also studied in order to test a new hypothesis on the origin of life: coupled dehydration-polymerization in silica-amino acid systems. The significance of organic-inorganic interactions in the fate of organic pollutants in the earth's surface will also be pointed out.

DOI： 10.2465/gkk.31.58

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DOI： 10.11316/butsuri1946.57.746

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Language：Japanese   Publisher：海洋出版  

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DOI： 10.18940/vsj.2002.2.0_52

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We report the first in situ observation of hollow organic globules in any extraterrestrial material using the Tagish Lake carbonaceous chondrite. Data from analytical transmission electron microscopy, Raman and micro-Fourier-transform infrared (FTIR) spectroscopy indicate that the globules consist of aliphatic and oxygenated functions. The hollow spherical morphologies are strikingly similar to the material produced by the laboratory simulation of ultraviolet photolysis of interstellar ice analogues and subsequent aqueous processing, suggesting that the organic globules in the Tagish Lake meteorite may be extremely primitive organic material that formed before or during the formation of the solar system. The FTIR organic signatures also show strong similarities to the membrane-like products formed from hydrothermal reaction of an OH-bearing amino acid in the presence of hydrous minerals. The survival of the structures in the Tagish Lake sample indicates that primitive meteorites must have delivered these structures to the early Earth as a possible precursor to life. © 2002, Cambridge University Press. All rights reserved.

DOI： 10.1017/S1473550402001167

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Language：Japanese   Publisher：Japan Society of Engineering Geology  

We applied the X-ray CT images of fluid advection in laboratory permeameter, which is made from acrylic plastics with low absorption of X-ray, in order to visualize the advecting fluid image during permeability testing and to elucidate the relationship between fluid flow property within fault-related rocks and their deformation mechanism. As a result, X-ray CT image can produce high resolution and three-dimensional fluid flow distribution was measured for fault-related rocks. The fault zones of independent particulate flow mechanism play a role as conduit to fluid flow while cataclastic fault zones act as barriers The localized permeabilities along permeable fault zones, calculated by fluid front rates, are approximately one-orders higher than averaged bulk permeability derived from the pressure or volume difference betweeninflow and outflow in permeameter.

DOI： 10.5110/jjseg.42.294

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Language：Japanese   Publisher：Japan Society of Engineering Geology  

The images of micro pores in geomaterials were visualized using an atomic force microscope. The hollow parts of AFM-image showed void space by the comparison with SEM-image. The AFM-image was transferred into the binary image of void structure by threshold at the grading scale based on the pore-size distribution and effective porosity. We can derive the geometric information, such as perimeter, pore square and hydraulic radius, of the visualized pore image using image-processing. The AFM is useful for the visualization and quantitative analysis of micro pore in geomaterials.

DOI： 10.5110/jjseg.42.24

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Language：Japanese   Publisher：The Geological Society of Japan  

DOI： 10.14863/geosocabst.2001.0_91_2

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Language：Japanese   Publisher：The Geological Society of Japan  

DOI： 10.5575/geosoc.106.909

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DOI： 10.5575/geosoc.106.816

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DOI： 10.5575/geosoc.106.165

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DOI： 10.14863/geosocabst.2000.0_118_2

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Language：English   Publisher：ECONOMIC GEOLOGY PUBL CO  

The reduction kinetics of uranyl cations to uraninite in aqueous solution by two lignites with different maturities were experimentally determined under diagenetic or hydrothermal conditions (180 degrees-200 degrees C). Both the uranyl reduction and lignite dehydrogenation reactions observed confirm previous mechanistic hypotheses (Nakashima et al., 1984, 1987; Nakashima, 1992a, b). Reduction is a first-order reaction with respect to uranyl cation and organic substrate. For both of the reactions studied, reduction and dehydrogenation, the activation energies measured in experiments using two different lignites were within experimental error. These values are 115 +/- 15 kJ/mol for uranyl reduction, and 59 +/- 13 kJ/mol for lignite dehydrogenation. Estimates of the half-lives of U in aqueous solutions have been completed based on the kinetic parameters by assuming that the rate-determining step is uranyl reduction to uraninite. The results suggest a rough time-scale range of U deposition rates with large uncertainties on the pre-exponential factor. The half-life of U precipitation is estimated to be on the order of 3 h to 1 yr under modest thermal conditions (200 degrees-100 degrees C), 340 yr for radioactive waste repositories (50 degrees C), and 10(4) to 10(5) yr at the Earth's surface (25 degrees-4 degrees C).

DOI： 10.2113/gsecongeo.94.7.993

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Language：English   Publisher：ECONOMIC GEOLOGY PUBL CO  

The reduction kinetics of uranyl cations to uraninite in aqueous solution by two lignites with different maturities were experimentally determined under diagenetic or hydrothermal conditions (180°-200°C). Both the uranyl reduction and lignite dehydrogenation reactions observed confirm previous mechanistic hypotheses (Nakashima et al., 1984, 1987; Nakashima, 1992a, b). Reduction is a first-order reaction with respect to uranyl cation and organic substrate. For both of the reactions studied, reduction and dehydrogenation, the activation energies measured in experiments using two different lignites were within experimental error. These values are 115 ± 15 kJ/mol for uranyl reduction, and 59 ± 13 kJ/mol for lignite dehydrogenation. Estimates of the half-lives of U in aqueous solutions have been completed based on the kinetic parameters by assuming that the rate-determining step is uranyl reduction to uraninite. The results suggest a rough time-scale range of U deposition rates with large uncertainties on the pre-exponential factor. The half-life of U precipitation is estimated to be on the order of 3 h to 1 yr under modest thermal conditions (200°-100°C), 340 yr for radioactive waste repositories (50°C), and 10 4 to 10 5 yr at the Earth's surface (25°-4°C).

DOI： 10.2113/gsecongeo.94.7.993

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Language：Japanese   Publisher：The Geological Society of Japan  

DOI： 10.14863/geosocabst.1999.0_36_2

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Language：Japanese  

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Language：Japanese  

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Language：English  

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Language：English  

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Language：Japanese  

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Language：Japanese   Publisher：The Volcanological Society of Japan  

High temperature infrared (1R) microspectroscopy has been developed for the in-situ characterization of structure, water and dehydration behaviors of magmas. Natural rhyolitic glasses were measured for their change in structures and water up to 1500℃. Based on recent in-situ data of water in alkali-aluminosilicate glasses suggesting the presence of more OH than H₂O, in-situ dehydration kinetics of hydroxyl(-OH) species from rhyolitic glasses were studied in detail by the above method. First order reaction rates and activation energies were determined for a natural rhyolitic glass from Kozushima and Wada-Toge (Obsidian), Japan at temperature ranges of 500-600℃ and 800-950℃ respectively. Activation energy values for the dehydration of these glasses varies from 70 to 130 kJ/mol. By comparing these with our data on dehydration kinetics of hydrous polycrystalline quartz aggregates (agate; 34, 70 and 190 kJ/mol) and muscovite (440 kJ/mol). together with literature data on water diffusion in melts/glasses (50-120kJ/mol), the main rate-determining step of dehydration of rhyolitic glasses is considered to be the diffusion of water. The diffusion profiles of water in obsidian were detected by micro-IR line analysis and gave reasonable diffusion coefficients. These data were used to evaluate a typical time scale of volcanic degassing at around 550℃ in the order of several hours.

DOI： 10.18940/kazan.42.Special_S19

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Language：Japanese   Publisher：The Geological Society of Japan  

DOI： 10.14863/geosocabst.1996.0_258_2

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Language：Japanese  

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Language：Japanese   Publisher：The Geological Society of Japan  

DOI： 10.14863/geosocabst.1995.0_29

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Language：Japanese   Publisher：The Geological Society of Japan  

DOI： 10.14863/geosocabst.1995.0_176_1

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Language：Japanese   Publisher：The Geological Society of Japan  

DOI： 10.14863/geosocabst.1994.0_131_2

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Language：Japanese   Publisher：The Geological Society of Japan  

DOI： 10.14863/geosocabst.1994.0_183_2

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Language：Japanese  

J-GLOBAL

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Language：Japanese  

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Language：Japanese   Publisher：The Geological Society of Japan  

DOI： 10.14863/geosocabst.1992.0_482

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Language：Japanese   Publisher：The Geological Society of Japan  

DOI： 10.14863/geosocabst.1991.0_420

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