Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acsanm.2c04489

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Publishing type：Research paper (scientific journal)   Publisher：Technical Association of Photopolymers, Japan  

DOI： 10.2494/photopolymer.35.213

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.mne.2022.100160

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Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

Fine particle bombarding (FPB) is typically utilized to modify metal surfaces by bombarding them with fine particles at high-speed. The diameters of the particles range from several to tens of micrometers. FPB forms fine microscale concavities and convexities on a surface. As FPB-treated surfaces are widely used in the food industry, the influence of bacteria on their surface must be considered. In this study, we examined the antibacterial activity of microscale rough surfaces formed by FPB. We applied FPB to a stainless-steel surface and evaluated the antibacterial effect of FPB-treated surfaces based on JIS Z 2801 (a modified test method from ISO 22196:2007). Our results indicated that the FPB-treated surfaces (FPB-1 (avg. pitch: 0.72 µm) and FPB-2 (avg. pitch: 3.56 µm)) exhibited antibacterial activity both against Escherichia coli and Staphylococcus aureus.

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DOI： 10.1186/s13568-022-01351-8

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Other Link： https://link.springer.com/article/10.1186/s13568-022-01351-8/fulltext.html

Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

The time profiles of active cell ratios depended on the growth phase and the absence of some lytic transglycosylases of E. coli. Significant cell damage was not found on the autolysis inhibition condition.

DOI： 10.1039/d1ra07623j

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An anodic aluminon oxide (AAO)-based nano honeycomb electrode was coated on a quartz crystal for use as a sensing device in a quartz crystal microbalance (QCM) to monitor the protein-protein interactions (PPIs). As examples, we detected PPIs of anti-Bcl-2 and Bcl-2, and Bcl-2 and Bax in real time. A sensor with a flat Au electrode showed a tiny frequency shift upon sample injection. However, our fabricated device could detect 10 μg/mL of Bcl-2 and Bax in sequence.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP PUBLISHING LTD  

Nanostructured Au was obtained on an electrode of a quartz crystal microbalance (QCM) chip by anodization in an oxalic acid solution. The effective surface area was expanded by these nanostructures and evaluated by electrochemical measurement, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Several morphologies, such as a nanosphere and a spongy structure, were observed under various anodic conditions. We demonstrated that a QCM chip with an anodized Au electrode was effective in biosensing because of its large surface area. The frequency shift corresponding to an antigen-antibody reaction improved on a Au nanosphere electrode compared with a flat surface electrode and spongy structure. (C) 2017 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.56.06GG04

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

Since the discovery of graphene by sticking and peeling scotch tape off graphite, it has also been prepared by other methods, such as thermal decomposition of SiC and chemical vapor deposition (CVD) with catalytic layer. Both the exfoliation and CVD methods impose to transfer the graphene layers on other insulating substrates for device applications. We reported that diamond grows in oxygen atmosphere (Yoshimoto, M.
et al. Nature 1999, 399, 340-342) in which oxidative etching and depositing carbon compete under equivalent conditions. However, oxygen atmosphere is too intense for graphite growth. Although carbon dioxide (CO2) is produced after hydrocarbon combustion, it can be a gentle and tender oxidant in certain situations. Here, we show the direct growth of graphene on insulating substrates in 100% CO2 environment and observe its layer-by-layer growth on the stepped edge of an insulating substrate. The direct growth can have a significant advantage of excluding the necessary process of transferring the graphene on the insulating substrate over other common methods.

DOI： 10.1021/acsomega.7b00140

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP PUBLISHING LTD  

A BaCuO2 thin layer was deposited on a glassy carbon electrode and used for the direct oxidation of glucose. The crystalline, electrochemical, and physicochemical properties that depend on the deposition temperature and deposition time were studied. X-ray diffraction (XRD) analysis showed that the thin layer was amorphous even at 400 degrees C. The current density of the glucose oxidation using the thin layer deposited at 200 degrees C was higher than those at other deposition temperatures. Under this condition, the current density increased with the glucose concentration and deposition time. These results indicate that a BaCuO2 thin layer has potential for measuring the blood glucose level without enzymes. (C) 2017 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.56.01AH02

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ナノ構造の作製法やそれを用いたデバイスについて紹介。

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

This work develops a novel method for preparing a moth eye structure, which has a sub-wavelength periodical Si nanocone structure on Si(100) substrate, using two-step metal assisted chemical etching (MACE). The 1st MACE and 2nd MACE were respectively performed with the intention to form perpendicular Si nanowire arrays on a Si substrate and sharpening the Si nanowire arrays. We found that the inhomogeneous absorption and aggregation of Au particles used as a catalyst for the 2nd MACE was important to obtain the nanocone shape. The obtained Si nanocone arrays showed superior anti-reflecting properties especially in a wavelength below 600 nm compared with the Si nanowire arrays. A possible mechanism involved in the formation of the nanocone structure by the 2 step MACE is discussed in this paper. (C) 2016 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.mee.2016.01.030

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：ELSEVIER SCIENCE BV  

QCM is one of major sensing methods for volatile organic compounds (VOC), however, the method is affected by environments such as temperature, humidity, and airflow. To cancel the signals affected by environments, we used twin sensor QCM which has two electrodes on one quartz substrate. In fact, one Au electrode was used as a reference, and ZnO thin film was electrodeposited on the other electrode to detect ethanol. The surface morphology of ZnO was changed corresponding to the applied potential on the electrodeposition. Scaly surface was obtained at -0.8 V vs. Ag/AgCl. QCM with scaly ZnO surface showed high frequency change on exposing to ethanol gas. (C) 2016 The Authors. Published by Elsevier Ltd.

DOI： 10.1016/j.proeng.2016.11.192

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

Cicada wings have nanostructures which shows superhydrophobic property, non reflecting to the light, and antibacterial characteristics. To mimic the nano structure of a cicada wing, we fabricated nano-pillar array using metal assisted etching. Fabricated nano-pillar array showed higher antibacterial property for E. coli. Our introduced process has advantages for industrial usage because of low cost and low environmental load based on wet process.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：ELECTROCHEMICAL SOC INC  

The nano structure derived from Anodic Aluminum Oxide (AAO) is controllable by the anodizing conditions such as voltage, anodizing time, and the acid solutions. Regularly arranged nanopores were fabricated with high aspect ratio. We tried to use the nano structure as a template to build nanowire array on the quartz crystal to enlarge the surface area bond to analyte. Evaluating the shape of the nanowire, average of the height and the diameter of the nanowire were 1 mu m and 50 nm, respectively. In this case, high aspect ratio more than 20 was achieved. We fabricated nanowires on the electrode of the QCM chip and tried to detect the antigenantibody reaction.

DOI： 10.1149/07516.0229ecst

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Electrochemical Society Inc.  

We studied magnetic conduction property of the conductive filament formed in the ReRAM device having two ferromagnetic electrodes. Anisotropic Magnetoresistance (AMR) property was observed in the ON-state of the devices, however, negative MR occurred for the one device and positive MR occurred for another devices, There were abrupt change of resistance around 250 mT for these devices. Micromagnetic simulation study strongly suggested that the abrupt change of MR was caused by the single domain switching of the magnetic conductive filament (MCF). Furthermore, it is suggested that typical MCF size was 40 x 40 x 4 nm1 by assuming that MCF was composed of Ni metals, It is also suggested that the difference of negative AMR and positive AMR is derived from the location of MCF. The present results suggest a possibility of new multilevel memory devices which can be operated by both electric field as well as magnetic field.

DOI： 10.1149/07532.0065ecst

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP PUBLISHING LTD  

Wurzite aluminum nitride is prepared on a c-plane sapphire substrate by electron cyclotron resonance plasma-enhanced sputtering deposition (ECR sputtering). Atomic force microscopy (AFM) showed flat AlN thin-film surfaces, and X-ray diffraction (XRD) analysis verified the epitaxial growth of AlN films with the full-width at half-maximum (FWHM) of the rocking curve of 0.025 deg on the film with the thickness of 100 nm. XRD analysis also verified the change in the peak position for the AlN film along both out-of-plane and in-plane directions. The effect of lattice constants on the energy gap was theoretically estimated by the first principles method. (C) 2014 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.53.11RA11

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

We present a rapid cortisol detecting system with the integration of flow injection analysis in order to adapt sequential analysis. The detecting system consists of a twin sensor chip on quartz crystal micro balance (QCM) method. One sensor monitored antigen-antibody interaction, together with the other sensor as a reference to remove environmental influences. A competitive assay was performed on monitoring the antigen-antibody interaction using cortisol coupled with bovine serum albumin (Crt-BSA) as a tracer. The binding between antigen and antibody could be uncoupled with a glycine-NaOH solution to adapt sequential analysis. One detection cycle, including regeneration step was performed within 10 minutes at a flow rate of 6 mu L min(-1). The sensor system could quantitatively detect cortisol levels ranging from 5 pg mL(-1) to 100 pg mL(-1). These results indicated the sensor system has the potential to be used for active stress-monitoring and in the diagnosis of disease.

DOI： 10.1039/c4ay01387e

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：ELSEVIER SCIENCE BV  

We propose a newly developed stress analysis system combined with quartz crystal microbalance (QCM) method and a self suction flow system. Cortisol, well known as a stress marker, was targeted in this study. The proposed system can be performed as quantitative analysis without professional skills by only dropping a liquid sample with the addition of a tracer. The system could detect cortisol within 8 minutes. Users can perform duplicate analysis by regenerating the sensor surface. These techniques are fit to monitor stress level at home. (c) 2014 The Authors. Published by Elsevier Ltd.

DOI： 10.1016/j.proeng.2014.11.666

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP PUBLISHING LTD  

Diamond-like carbon (DLC) has been applied as a coating material to improve the basic properties of strength, chemical stability, and biocompatibility. In this study, a DLC film was prepared on a titanium (Ti) coating film with tetramethylsilane (TMS) buffer for application in vivo. Although the surface roughness of the Ti film increased with increasing Ti thickness, both TMS and DLC coatings deposited on Ti films resulted in the formation of a flat surface. Observation of the initial growth of the TMS layer indicated that a TMS buffer of more than 50nm thickness was required for DLC coating even on the flat surface of the Ti thin film. (C) 2013 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.52.11NA02

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

After CW lasers scanned a target at high speed of 300 m/min, periodical nanostructure self-organized on the target surface. Unlike fiber-like structure fabricated by femtosecond laser, the periodic structure showed trench structures with flat bottoms. A theoretical simulation of thermal distribution of the target indicated the target temperature exceeds its melting point, which was verified by micro-Raman spectroscopy. The time dependent thermal distribution indicated the existence of threshold melting period to form the trench nanostructure. The nanostructure showed well-regulated gratings, and the precise periodicity emerged structural color and modified water-repellent on the target surface. © 2012 Elsevier Ltd.

DOI： 10.1016/j.optlaseng.2012.09.011

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP PUBLISHING LTD  

Magnesium oxide (MgO) prepared by both pulsed laser deposition and sputtering methods showed constriction of lattice constants. To emphasize the effect of the constriction of lattice constants, MgO prepared at high oxygen atmosphere and high substrate temperature, resulted in the growth of cubic-shaped magnesium oxide (MgO) nanoparticles on a Si substrate. In oxygen atmosphere, the nanocubic MgO was scattered on the substrate without the Si surface being covered by a MgO thin film. Interestingly, the growth of nanocubic MgO was restrained on the samples prepared in nitrogen atmosphere. The formation of nanocubic MgO is related to the deposition pressure as well as the etching effect provided by oxygen atmosphere. (C) 2013 The Japan Society of Applied Physics

DOI： 10.7567/JJAP.52.01AN02

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

We prepared AlN film on c-plane sapphire substrate by electron cyclotron resonance plasma-enhanced sputtering deposition (ECR-sputtering). X-ray diffraction (XRD) verified the epitaxial growth of AlN films with the full width at half maximum (FWHM) of rocking curve of 0.04 deg. even on the film thickness of 100 nm. XRD also verified slight change of peak position from AlN film along both out of plane and in-plane directions.

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

We propose novel electrodes with platinum nanoparticles dispersed on a glassy carbon (Pt-NPs/GC) prepared using a pulsed arc plasma deposition (APD) method. The method could coat Pt-NPs on a base material directly with a single-step process in a very short deposition time. The characteristics of the electrodes were discussed in detail. The detection of hydrogen peroxide was performed as an example for application of the electrodes. The distribution of nanoparticles was controlled easily by the number of pulse. The surface morphology changed with the pulse number and the annealing except for the sample prepared by 5 pulses deposition (APD(5)), implying that the APD(5) remained as NPs after the annealing. Average particle size was 2.7 nm on the Pt-NPs/GC. Catalyst activity for oxidizing hydrogen peroxide per Pt loading was excellent on the Pt-NPs/GC. When the Pt-NPs/GC was used as a detector for hydrogen peroxide on a flow injection analysis, the Pt-NPs/GC showed high sensitivity without deterioration. Oxidation current increased linearly with the concentration of hydrogen peroxide from 10 nM to 100 mu M. This fast and easily prepared electrode showed the capability to replace a conventional bulk metal electrode. (C) 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.talanta.2012.07.048

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

We developed a 3D interdigitatecl (IDA) array electrode consisting of Au nano particles, which increase the electrode surface. The electrode was fabricated using microfabrication and printing techniques. Electrochemical impedance spectroscopy was conducted to measure IgG concentration, when anti-IgG was immobilized onto Dithiobis (succinimidyl propionate) (DTSP) SAM/3D-IDA electrode. A linear relationship between charge transfer resistance (R-ct) values and the logarithm of IgG concentration was observed in the range of 1 mu g/ml to 1 mg/ml. (C) The Electrochemical Society of Japan, All rights reserved.

DOI： 10.5796/electrochemistry.80.305

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：EDP SCIENCES S A  

Epitaxial magnesium oxide (MgO) thin films prepared on Si(0 0 1) substrates revealed the contraction of its lattice constants along both out-of-plane and in-plane directions. X-ray Diffraction (XRD) verified the epitaxial growth with the relation of MgO(1 0 0) parallel to Si(1 0 0) [cubic on cubic growth] with large lattice misfit of similar to 22% instead of the relation of MgO(1 1 0) parallel to Si(1 0 0) [45 degrees rotation growth] with lattice mismatch of similar to 9%. Although the domain epitaxy explaining the cubic on cubic growth is preferred in terms of crystallography, structural stability is not considered in the concept of the domain epitaxy. In order to explain the contraction of lattice constant from point of view of structural stability, ab initio method was used to evaluate all-electron total energy, and optimal lattice constant was estimated with point defects in the MgO structure.

DOI： 10.1051/epjap/2012110247

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER SCIENTIFIC PUBLISHERS  

Nano-cube MgO particles were formed on Si substrates by deposition of an MgO target using pulsed laser deposition method. An epitaxial film grows on Si(001) substrate with its contraction of lattice constants.(19) In this study, expecting high quality MgO film, the MgO film prepared in the oxygen pressure ranging from 75 similar to 400 mTorr at the high temperature of similar to 750 degrees C. The deposited MgO showed the growth of (001) preferred orientation on the Si(001) substrate. However, X-ray Photoelectron Spectroscopy (XPS) indicated the MgO film did not form a continuous film on the Si surface. Interestingly, the surface morphology observed by an Atomic Force Microscopy (AFM) showed nano-cube MgO particles scattered on the smooth surface of Si substrate. After annealing the nano-cube MgO, the shape of MgO particles were changed from nano-cube to round shaped particles. The AFM image of the surface showed round shaped MgO nanoparticles scattered on rough surface. X-ray Diffraction (XRD) revealed the epitaxial growth of MgO(001) with cubic on cubic arrangement on the Si(001) substrate (MgO[100] parallel to Si[100]).

DOI： 10.1166/jnn.2012.5688

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

Metallization multilayers on the back side of a power device were focused in this study. Si wafers coated with high melting point metals were exposed at 300 degrees C for 300 h to investigate diffusion condition of the metallization layer. We developed and examined the thermal stability oldie bonding material (Au paste) including sub-micrometer-sized Au particles. Auger electron spectroscopy was applied to observe the atomic composition of the multilayers in depth direction after the high temperature aging. Surface morphology was observed using optical microscope and scanning electron microscope. While atomic composition on Ti/Au changed drastically after the high temperature aging, other multilayers maintained their metallization composition. However, the surface morphology was slightly changed on Ti/Ru/Au, W/Au, and Ta/Au. Bond strength on the Ti/Pt/Au kept over 40 MPa with unified bonding layer after exposing at 300 degrees C for 1000 h. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.microrel.2011.07.094

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：SPIE-INT SOC OPTICAL ENGINEERING  

We report periodic nanostructure on solid material irradiated by scanning continuous wave (CW) laser. Long periodic nano strip grating lines (nano-SGL) formed, not in a spot, but along the trace of the beam scan, literally parallel to each other with a flat trough between the strip lines. The period of nanostructure was varied with the laser power between 500 nm and 800 nm, which equals to wavelengths used for laser scanning of green and infrared lasers. Thermal simulation and Raman spectra indicated the temperature of target exceeded the melting temperature to form the periodic nanostructure on target materials.

DOI： 10.1117/12.905970

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We proposed a low cost fabrication procedure of a poly(methylmethacrylate) (PMMA) column chip. 3D microchannel structure consisting of four columns in a chip for a mother die was fabricated using dry film photoresist and photolithography technique. Electroforming was applied to the mother die in order to obtain a Ni mold, then, the pattern was transferred to PMMA by hot press. The column had a dam structure to keep enzyme-immobilized microbeads with volume of 640 nL. The column chip was applied for a micro flow injection analysis (mu FIA) system. For a demonstration, we measured lactose using two columns in series. One column was set on upper stream and filled with chitosan microbeads immobilized with beta-galactosidase, the other was on downstream and filled with the beads immobilized with glucose oxidase. The lactose detection was accomplished less than 90s after the sample injection. The biosensing system also showed a high performance for lactose detection in wide range of 1 mu M to 1 mM. These results show that the column chip and our microfluidic biosensing system have the potential to assist minuaturization with small sample volume and short determination time for a sequential analysis. (C) 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.talanta.2011.04.053

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP PUBLISHING LTD  

After a laser annealing experiment on Si wafer, we found an asymmetric sheet resistance on the surface of the wafer. Periodic nano-strip grating lines (nano-SGLs) were self-organized along the trace of one-time scanning of the continuous wave (CW) laser. Depending on laser power, the nano-trench formed with a period ranging from 500 to 800 nm with a flat trough between trench structures. This simple method of combining the scanning laser with high scanning speed of 300 m min(-1) promises a large area of nanostructure fabrication with a high output. As a demonstration of the versatile method, concentric circles were drawn on silicon substrate rotated by a personal computer (PC) cooling fan. Even with such a simple system, the nano-SGL showed iridescence from the concentric circles.

DOI： 10.1088/0957-4484/22/17/175307

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

Metal oxide nanoparticles prepared by pulsed laser deposition (PLO) were applied to nonenzymatic glucose detection. NiO nanoparticles with size of 3 nm were deposited on glassy carbon (GC) and silicon substrates at room temperature in an oxygen atmosphere. Transmission electron microscope (TEM) image showed nanoparticles with the size of 3 nm uniformly scattered on the Si(0 0 1) substrate. Unlike co-sputtering nanoparticle and carbon simultaneously, the PLO method can easily control the surface coverage of nanoparticles on the surface of substrate by deposition time. Cyclic voltammetry was performed on the samples deposited on the GC substrates for electrochemical detection of glucose. The differences between peak currents with and without glucose was used to optimize the coverage of nanoparticles on carbon electrode. The results indicated that optimal coverage of nanoparticles on carbon electrode. (C) 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.talanta.2010.12.040

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As application of re-activation of backside on power device Insulated Gate Bipolar Transistor (IGBT), laser annealing was employed to irradiate amorphous silicon substrate, and resistivities were measured using four point probe measurement. For annealing the amorphous silicon two lasers were used at wavelength of visible green (532 nm) together with Infrared (793 nm). While the green laser efficiently increased temperature at top surface the Infrared laser reached more deep inside and was effective for melting the top surface. A finite element method was employed to evaluate time dependent thermal distribution in silicon substrate.

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

Ultrathin layer of platinum (ULPt) was deposited on glassy carbon (GC) substrate by using pulsed laser deposition (PLD) method, and electrochemical properties of the ULPt were discussed. The deposition was simply performed at room temperature with short deposition time. Atomic force microscopy and scanning electron microscopy images showed the flat surface of the ULPt. X-ray photoelectron spectroscopy (XPS) characterized the ULPt in the Pt(0) state, and biding energy of ULPt was positively shifted. These results indicated that nanostructure of Pt thin layer was formed. The electrochemical activity of the prepared ULPt on GC substrate was superior to a bulk Pt electrode regarding the potential and the magnitude of current on oxidizing hydrogen peroxide. This fast and easily prepared low-cost electrode had the potential to replace a conventional bulk metal electrode.

DOI： 10.4061/2011/463281

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Epitaxial growth of MgO was verified with the relation of MgO(100) parallel to Si(100) (cubic on cubic growth) even with a large mismatch of lattice constants ∼ 22%, instead of 9% mismatch in 45° rotation growth. MgO films prepared at higher deposition temperature showed (001) preferred orientation on Si(001) substrate. After post-annealing the MgO thin films, the pole figure of X-ray diffraction verified the epitaxial growth of cubic on cubic relation. Fe3Si thin film was deposited on Si(001) substrate with the MgO film as buffer layer. © 2011 Ceramic Society of Japan.

DOI： 10.1088/1757-899X/18/2/022018

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

The growth of an epitaxial film with a large lattice misfit to substrates is interpreted as domain growth with domain matching by the coincidence site 1 lattice (CSL), in which it is assumed that (m x n) film lattice units are superimposed on (k x l) substrate lattice units The domain matching with all combinations of two lattice units was expanded on a polar coordinate system (polar CSL figure), where the radius and angle are indicative of the domain size and the lateral angle between two superimposed lattices, respectively The polar CSL figure enable us to visualize the domain matching of all combinations between the two lattice units (k x l) and (m x n) The cubic-on-cubic growth of magnesium oxide on a silicon substrate and the lateral rotation of bismuth cuprate oxide were taken as examples of visualization using the polar CSL figure (C) 2010 The Japan Society of Applied Physics

DOI： 10.1143/JJAP.49.08JE02

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

Epitaxial thin films prepared using an MgO target on silicon substrate often show constriction of lattice constant (a similar to 4.1 angstrom). Detailed investigation of the crystal structure excluded the possibility that the epitaxial films are either cubic spinel MgO or magnesium silicate (a/2 similar to 4.1 angstrom). With such a constriction in rock salt MgO structure point defects must be induced into structure. An ab initio method with semicore pseudopotentials predicted such constrictions on configurations of Schottky type defects. The Schottky defects with random distribution throughout lattice cites satisfied constricted lattice constant, mass density, and crystallography experimentally observed on the epitaxial MgO films. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3361482]

DOI： 10.1063/1.3361482

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We studied electrochemical responses and morphologies of metal nanoparticles (MNPs) which were prepared by using pulsed laser deposition (PLD) method. Pt and NiO were deposited on a silicon (Si) and a grassy carbon (GC) substrate. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) images did not determine their nanoparticles. Auger Electron Spectroscopy (AES) and X ray Photoelectron Spectroscopy (XPS) for Pt and NiO coated Si substrates showed that MNPs were certainly formed. Pt with the deposition time of 60 sec had highest activity to detect hydrogen peroxide in phosphate buffer solution. NiO with the deposition time of 90 sec showed highest activity to detect glucose in sodium hydroxide solution. These characteristics might be caused by catalytic activity of MNPs. ©The Electrochemical Society.

DOI： 10.1149/1.3316108

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

We designed and prepared a micro biosensing system consisting of a flow through system with a sub-micro liter injection valve and a sub-micro liter volume bioreactor. An electrochemical detector was combined with the reactor for immediate detections.The volumes of the reactor and the sample loop for the injection were 850 nl and 320 nl, respectively. This paper described about the characteristics of the sensing system in the case of histamine detection for food analysis. Histamine oxidase from KAIT-B-007 was prepared by using a gene recombination technique and they were immobilized with chitosan beads (phi = 70-105 mu m). The detection less than one minute after injection made possible fast analysis for histamine.The biosensing system also showed a high performance for histamine detection in wide range of 1 mu M- 1 mM. In addition, we practically measured histamine content in raw tuna stored at room temperature and 35 degrees C up to 96 h. As a result of the comparison between our sensing system and HPLC method, there was good agreement. These results show that our microfluidic biosensing system has the potential to assist miniaturization with small sample volume and short determination time for a sequential food analysis. (C) 2008 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.talanta.2008.08.018

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELECTROCHEMICAL SOC INC  

We proposed a design and fabrication technique for a micro proton exchange membrane fuel cell (mu-PEMFC). Thin current collector plates had microgrooves for fuel supply. Microgrooves with a line and space of 100-500 mu m and depth of 112 mu m were fabricated by using microfabrication technologies. Maximum power density increased with increasing line and space of the fuel channel, and a high power density of 109 mW/cm(2) was achieved at the line and space of 100 mu m. Ohmic resistance decreased with increasing line and space of the fuel channel. A low ohmic resistance of 0.26 cm(2) was determined. These results were comparable to the conventional PEMFC, and preliminary test results showed that our mu-PEMFC is as useful as a miniature PEMFC.

DOI： 10.1149/1.3202382

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

The strain induced by a multilayered structure affects how strongly unit cells are distorted to form structural modulations (supercell: SC in bismuth cuprate superconducting films. On the contrary to the multilayered structure, the strain will be released in a single thick film. To investigate the effect of strain oil the SC structure, a relatively thick Bi2Sr2Ca1Cu2Ox (Bi-2212 film was prepared oil a MgO(001) substrate, and the SC structure in the thick film was compared with those ill single thin film and the multilayered films. With the increase in film thickness from a few layers to a few tens of hundred layers, another phase of Bi-2212 became a dominant structure, which rotated around the Surface normal with ail angle of 32 degrees. The distortion became weak in the thick film. resulting in the weak satellite generated by the SC structure.

DOI： 10.1143/JJAP.47.5602

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

Yttria-stabilized zirconia (YSZ) was epitaxially grown on both Si(0 0 1) and Si(1 1 1) substrates using a RF magnetron sputtering method. While YSZ(0 0 1) was grown on Si(0 0 1) with a cubic on cubic relation, YSZ(1 1 1) film on Si(1 1 1) with six-fold symmetry on surface showed two variants; cubic on cubic (type A) and 180 degrees rotation about surface normal along [1 1 1] (type B). X-ray diffraction method confirmed single domain YSZ with type B structure when samples were prepared with the relatively slow deposition rate and low substrate temperature. Interestingly, in a reverse pairing of substrate and film, Si deposited on YSZ(1 1 1) substrates showed single domain with type A structure. (c) 2007 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

DOI： 10.1016/j.ceramint.2007.09.087

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

X-ray reciprocal space mapping (XRSM) revealed asymmetric intensity distribution of satellite peaks, caused by structural modulation, so-called supercell (SC), of the bismuth cuprate film Bi2Sr2Ca1Cu2Ox (Bi-2212). How unit cells are distorted to form SC is investigated on multilayered structure, which induces extra strain into unit cells. In order to investigate the effect of displacement of relatively heavy bismuth on intensity and distribution of SC peaks on XRSM, modulation waves were applied into not the whole crystal but to specified atoms constructing structural modulation as a simple crystal model, and the simulation was compared to the experimental results. To the contrary to multilayer, in this study, relatively thick films were prepared, which released the strain in its single layer. Epitaxial growth was verified by X-ray diffraction with relation of 32 degrees rotation with respect to the surface normal of the initial epitaxial Bi-2212 film. (C) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jcrysgro.2007.11.071

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

The multilayered structure of bismuth cuprate superconducting film (Bi(2)Sr(2)Ca(1)Cu(2)O(X)/Bi(2)Sr(2)Cu(1)O(X)) affects the supercell consisting of several unit cells as well as the lattice constant of each layer. A relatively thick film of epitaxial Bi(2)Sr(2)Ca(1)Cu(2)O(X) (Bi-2212) was prepared to determine its crystal structure and to compare with a reference film of similar to 1000 angstrom thickness and a multilayered structure. As the Bi-2212 film grew continuously, the film was rotated by 32 degrees around the surface normal with respect to the initial layer of Bi-2212. The angle can be interpreted according to the coincidence site lattice (CSL) with E 17 and 18.

DOI： 10.1143/JJAP.47.664

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：TRANS TECH PUBLICATIONS LTD  

Bismuth cuprate superconductor has a unique structure called a structural modulation (supercell, SC) consisting of modulated several unit cells. Strain induced by multilayered structure increases the intensity of SC modulation, while an oxygen deficient sample shows expansion of SC size. In this study, as opposed to the multilayer strain, by preparing samples with thick film thicknesses the effect of strain on crystal structure was investigated including SC structure. Epitaxial growth was verified by x-ray diffraction, and the thicker film showed other epitaxial phase rotated 32 degrees around the surface normal with respect to the initial epitaxial phase. The SC size estimated by x-ray reciprocal space mapping was double the size of the initial epitaxial phase. Interestingly, the initial epitaxial phase became a dominant structure after further deposition. In order to evaluate the different SC size and SC modulation, a new index related with an incline of the modulation vector was proposed.

DOI： 10.4028/www.scientific.net/SSP.139.53

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Publishing type：Research paper (scientific journal)  

We investigated the characteristics of microfluidic devices fabricated using photosensitive sheets adhered to substrates. We evaluated them in regard to practical criteria, namely chemical resistance, pressure sealing, electrical resistance and elution of ions. No samples exhibited peeling after postbaking when we investigated the adhesion characteristics by dicing. The sheet swelled dramatically on exposure to an alkaline solution. The microfluidic devices consisting of photosensitive sheet sandwiched by two Pyrex substrates and a photosensitive sheet sandwiched by two PMMA substrates had a pressure sealing of 0.6 MPa, were capable of withstanding a pressure of 0.2 MPa for 1 h when ultrapure water was injected. The sheets had a high volume resistivity (9.7 × 1012 Ω cm) and a high surface resistivity (2.3 × 1011 Ω) after postbaking. Sodium ions were adsorbed onto the photosensitive sheet and then gradually desorbed. The total amount of sodium ion elution per unit area over 24 h was 8.3 × 10-9 mol mm -2 as measured by ion exchange chromatography. These results confirm that microfluidic devices fabricated using photosensitive sheets are suitable for use as disposable devices for certain applications. © 2007 IOP Publishing Ltd.

DOI： 10.1088/0960-1317/17/3/003

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

We designed and prepared a novel microbiosensing system consisting of a microbioreactor fabricated using photosensitive sheets intercalated between Pyrex wafers as a dam structure, together with a micro fuel cell as a power source device between the electrodes for amperometric detection. The dam structure retains enzyme (glucose oxidase, GOx)-immobilized microbeads in a microchannel. Microelectrodes are used as an integrated detector within a microchannel located downstream of the dam structure, and these are used to detect the oxidation current of hydrogen peroxide produced from a glucose sample and GOx. A micro direct methanol fuel cell (mu-DMFC, i.d. 500 mu m) was fabricated on a polymeric substrate and was used to supply a potential for the electrochemical detector. In this case, two mu-DMFCs were stacked on one substrate to increase the voltage for the oxidation of hydrogen peroxide. A linear response curve was obtained in range from 0.1 to 10 mM glucose for the designed microbiosensing system. These results show that a microfluidic biosensing system designed with a mu-DMFC device is useful and has the potential to assist minuaturization and simplification of the sensing system, in addition to increasing disposability of the device.

DOI： 10.1021/ac0618167

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

Yttria-stabilized zirconia (YSZ) films were prepared on Si(I 11) substrates with a slow deposition rate. X-ray diffraction clearly showed epitaxial growth of YSZ(111) film on Si(111), the X-ray phi scan of 3-fold symmetry confirmed single domain YSZ(111) to be rotated 180 degrees about the surface normal from cubic on cubic relation. In contrast, single domain Si(111) films showed cubic on cubic relation with the YSZ(111) substrate.

DOI： 10.1143/JJAP.45.L1328

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

We propose a novel design and fabrication technique for a micro direct methanol fuel cell (mu-Direct methanol fuel cells (DMFC)). Ten mu-DMFCs were fabricated on a polymeric flexible substrate containing a micro-holes array (empty set = 500 mu m). Our concept is that a high voltage DMFC can be achieved through the integration of a micro DMFC array on one flexible substrate. With 10 cells in series on the substrate, we achieved an open circuit voltage of 5.6 V and an average cell power density of 3 mW cm(-2). Further, none of the cells failed after subjecting the substrate to 1000 fold repetitions. Preliminary test results show that our DMFC fabricated on a polymeric substrate is useful as a miniature DMFC. (C) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.elecom.2006.03.044

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Publishing type：Research paper (scientific journal)  

We describe a low cost and high performance fabrication process to make a polymeric microfluidic device. The original microfluidic device pattern was made of a flat photosensitive sheet in which a mold base device was fabricated using the combined techniques of both electroforming and photolithography. As an example of our novel process, an electrophoresis chip was prepared using poly(methyl methacrylate) (PMMA) for a DNA analysis. The result shows that the fabricated chip has an equivalent DNA separation performance when compared to a similar ready-made product. © 2006 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.45.L64

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

X-ray reciprocal space mapping (XRSM) was employed to investigate epitaxial Bi2Sr2Ca1Cu2Ox(Bi-2212) film. Ordinal cross section XRSM (omega-2theta) and plan view XRSM (omega-psi) clearly indicated asymmetric intensity distribution of four satellite peaks caused by supercell structure of Bi-2212 film. Modulation vector estimated by XRSM was q=0.2b(*)+0.9c(*). The XRSM image simulated by sawtooth wave vector showed good agreement with asymmetric satellite peaks observed on epitaxial film. (C) 2004 American Institute of Physics.

DOI： 10.1063/1.1794376

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

Yttria-stabilized zirconia (YSZ) was grown on Si (100) substrate by pulsed laser deposition (PLD). The laser used in this study was a 266 nm YAG laser with a second function generator modulating only the Q-switch while the primary generator modulated the flash lamp (slower Q-switch). Epitaxial growth was verified on YSZ film deposited without oxygen gas followed by primary deposition in oxygen atmosphere on Si substrate with a similar to0.4-nm-thin oxide layer. The crystallinity was strongly dependent on the thickness of the buffer layer deposited prior to the primary deposition of YSZ. The epitaxial growth was confirmed by phi scan, and omega scan (rocking curve) showed the full width at half maximum (FWHM) of 1.1 deg. The required oxygen pressure for epitaxial growth was quite high compared to that of excimer deposition.

DOI： 10.1143/JJAP.43.1532

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Language：English   Publisher：Vacuum Society of Japan  

The fourth harmonic of Q-switched YAG was used to deposit yttria-stabilized zirconia (YSZ) film on Si(100) substrate. A secondary function generator was employed to modulate Q-switch while the primary generator was synchronized with flash lamps to decrease repetition rate of laser beam. At rate of 2 Hz, beam energy increased ∼ 50% per pulse. YSZ film was deposited on Si(100) using 3 mol% YSZ sintered pellet and ∼ 9 mol% single crystal YSZ as targets. In order to improve crystallinity of YSZ, two-step deposition was also carried out
deposition in oxygen insufficient atmosphere followed by oxygen sufficient atmosphere. The full width at half maxim (FWHM) of rocking curve showed ∼1.4° for the film produced by two-step deposition on Si substrate with thin SiO2 layer using single crystal YSZ as a target.

DOI： 10.3131/jvsj.47.581

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