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Ibaraki, Japan

Iwase K.,Ibaraki University | Mori K.,Kyoto University | Hishinuma Y.,ART KAGAKU Co. | Hasegawa Y.,ART KAGAKU Co. | And 4 more authors.
International Journal of Hydrogen Energy | Year: 2011

We developed a sample holder for in situ measurement of hydrogen absorbing alloy. In order to prevent the hydrogen absorption by vanadium, copper is coated with 2 μm thickness on inner surface of the vanadium holder. The effect of copper coating and the performance of the holder were evaluated by neutron diffraction and PDF profiles. The lattice parameters a and c of La 2Ni7 with Ce2Ni7-type structure were refined as 0.505921(4) and 2.468608(4) nm by Rietveld analysis. The Cu-Cu correlation peak around r = 0.255 nm was not observed in the PDF profile. Thus the holder is useful for in situ measurement of hydrogen absorbing alloy. The diffraction and PDF profiles of La2Ni7Dx (0 < x < 10.5) were collected using a deuterium pressure of 3.7 MPa, and the changes of crystal and local structures were clearly observed. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved. Source


Taguchi T.,Japan Atomic Energy Agency | Hasegawa Y.,ART KAGAKU Co. | Shamoto S.,Japan Atomic Energy Agency
Journal of Nuclear Materials | Year: 2011

SiC/SiC composites with and without dispersed carbon nanofiber were fabricated by the polymer impregnation and pyrolysis process. The effect of dispersing carbon nanofiber on the mechanical and thermal properties of SiC/SiC composites was investigated. The bending strength and elastic modulus of SiC/SiC composites with carbon nanofiber decreased slightly compared to those of the SiC/SiC composites without the nanofiber. On the other hand, the thermal conductivity of SiC/SiC composites increased with increasing amount of dispersed nanofiber. The dominant reason is considered to be that the pore shape changed from an oblong shape perpendicular to the direction of heat flow to an isotropic. The shape change resulted from the dispersed carbon nanofiber. © 2010 Elsevier B.V. All rights reserved. Source


Namazu T.,University of Hyogo | Ishikawa T.,University of Hyogo | Hasegawa Y.,ART KAGAKU Co. | Kuroda K.,Silveralloy Co. | And 2 more authors.
IOP Conference Series: Materials Science and Engineering | Year: 2011

In this paper, a new technique for fabricating silicon carbide (Si-C) microelectromechanical systems (MEMS) is described. Slip casting to UV-thick photoresist (SU8) micro mold was carried out for the fabrication of three-dimensional Si-C MEMS parts. Ultrahigh molecular weight polycarbosilane (PCS) was used as the precursor. Si-C nano powder was firstly mixed with a PCS solution, and then the slips were cast into SU8 micro mold fabricated on porous tungsten carbide (WC) plate. Firing at 1273 K was conducted for SU8 evaporation and PCS pyrolysis simultaneously. We have succeeded in producing Si-C ceramics micro gears using the "μ slip casting" technique. © Published under licence by IOP Publishing Ltd. Source


Ishikawa T.,University of Hyogo | Namazu T.,University of Hyogo | Yoshiki K.,University of Hyogo | Inoue S.,University of Hyogo | Hasegawa Y.,ART KAGAKU Co.
Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS) | Year: 2010

In this paper, we describe a new production method for microscale silicon carbide (SiC) ceramics parts. Slip casting with SU8 micro mold was carried out for the fabrication of a three-dimensional SiC MEMS component, which was made from polycarbosilane (PCS) precursor-derived SiC nano powder. SiC nano powder was mixed with a PCS solution. The slips were then cast into SU8 micro mold made on porous tungsten carbide (WC) plate. Firing at 1273 K was conducted for SU8 evaporation and PCS pyrolysis. We have succeeded in producing microscale SiC ceramics gears using the "μ slip casting" technique. ©2010 IEEE. Source


Akutsu K.,Comprehensive Research Organization for Science and Society CROSS | Niizeki T.,ART KAGAKU Co. | Nagayama S.,ART KAGAKU Co. | Miyata N.,Comprehensive Research Organization for Science and Society CROSS | And 4 more authors.
Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi/Journal of the Ceramic Society of Japan | Year: 2016

The structures of a SiO2 layers synthesized using perhydropolysilazane [PHPS, labeled as SiO2(PHPS)] on both Si and Fe/Si substrates were studied using Fourier transform infrared spectroscopy (FT-IR) and neutron reflectivity (NR) analysis. The FT-IR results revealed that no unreacted PHPS remained and that the primary component of the SiO2(PHPS) layer could be considered to be SiO2. The NR analysis suggested that a uniform SiO2(PHPS) layer was synthesized on the Si and Fe/Si substrate and that the density of this SiO2(PHPS)layer was lower than that of natural SiO2. In addition, the density of the SiO2(PHPS) layer was altered by varying both the thickness and the type of substrate used. These results indicated that the variation in the density of the SiO2(PHPS) layer depended on the efficiency of cross-linking reaction between the silazane oligomers in the PHPS coating. © 2016 The Ceramic Society of Japan. All rights reserved. Source

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