Physics and Energy Engineering

Nagoya-shi, Japan

Physics and Energy Engineering

Nagoya-shi, Japan

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Ogawa S.,Nagoya University | Fujimoto T.,Physics and Energy Engineering | Mizutani T.,Physics and Energy Engineering | Ogawa M.,Ritsumeikan University | And 7 more authors.
Surface and Interface Analysis | Year: 2014

The nanoparticles composed of Mg and Pd atoms (Mg-Pd NPs) have been fabricated by the gas evaporation method, and the variation of the chemical state during hydro-/dehydrogenations has been investigated by X-ray photoelectron spectroscopy (XPS) and in-situ X-ray absorption fine structure (XAFS) analyses. Both XPS and XAFS spectra have indicated that the Mg-Pd NPs contain the chemical state of the metallic Pd and Mg-Pd alloy phases. The Mg-Pd alloy phase has been identified as MgPd and Mg6Pd by the Pd K-edge EXAFS analysis. The hydrogen release of the Mg-Pd NPs has not been observed after first hydrogenation due to the migration of Mg toward the surface of the Mg-Pd NPs during the hydrogen storage. This irreversible migration has led the inhibition of the hydrogen diffusion into the surface from the inside of the Mg-Pd NPs. © 2014 John Wiley & Sons, Ltd.


Moniruzzaman Md.,Physics and Energy Engineering | Fukaya H.,Physics and Energy Engineering | Murata Y.,Physics and Energy Engineering | Tanaka K.,Kyoto University | And 2 more authors.
Materials Transactions | Year: 2012

Diffusion of Ti, V, Nb, Mo and Ta in Ni3Al phase was investigated at different temperatures using NiAlX (X= Ti, V, Nb, Mo, Ta) pseudo-binary diffusion couples. The magnitude of the interdiffusion coefficients was in the descending order of V, Mo, Ti, Nb and Ta at all experimental temperatures ranging from 1423 to 1573 K. Diffusion data obtained in this study was compared with those of Re and Ru available in the literature as Re and Ru are recently being added in modern Ni-based superalloys. Diffusion retardation occurred for Ti, V, Nb, Mo and Ta as compared to Ru, and this can be explained by the anti-site diffusion mechanism. The high activation energy for anti-site formation is required for β-site (Al-site) elements, such as Ti, V, Nb, Mo and Ta. However, as Ru can diffuse either by α- (Ni-site) or β-site preferences without creating local disorder, Ru diffusion is not retarded by the anti-site diffusion mechanism. © 2012 The Japan Institute of Metals.


Ogawa S.,Physics and Energy Engineering | Fujimoto T.,Physics and Energy Engineering | Kanai T.,ATSUMITEC Co. | Uchiyama N.,ATSUMITEC Co. | And 5 more authors.
e-Journal of Surface Science and Nanotechnology | Year: 2015

The hydrogen absorption behavior of the Pd NPs has been investigated by the noble techniques. The Pd NPs with the clean surface have been fabricated by the gas evaporation method. The P-C isotherm of the hydrogen absorption of the Pd NPs has been obtained using the QCM without the exposure to the air. The P-C isotherms have shown the clear size dependent absorption behavior for the Pd NPs. Further absorption and desorption cycles decrease the solubility of H significantly in the Pd NPs. © 2015 The Surface Science Society of Japan.


Cong Z.,Physics and Energy Engineering | Murata Y.,Physics and Energy Engineering | Tsukada Y.,Nagoya Institute of Technology | Koyama T.,Nagoya Institute of Technology
Materials Transactions | Year: 2012

The formation mechanism of the sub-block microstructure in lath martensite is explained by a two-type-slip deformation (TTSD) model. To simulate the sub-block structure morphology, the TTSD model is coupled with the phase field method resulting in the elastoplastic phase field model. The sub-block structure of lath martensite in Fe0.1C mass% steel is simulated in 3-D by employing the elastoplastic phase field model, which helps with the understanding of the formation mechanism of the sub-block structure in lath martensite. © 2012 The Japan Institute of Metals.


Endo T.,Physics and Energy Engineering | Watanabe T.,Physics and Energy Engineering | Watanabe T.,Nagoya University | Yamamoto A.,Physics and Energy Engineering | Yamamoto A.,Nagoya University
Journal of Nuclear Science and Technology | Year: 2015

Confidence interval estimation by the bootstrap method is investigated for the uncertainty quantification of neutronics calculation using the random sampling method. The random sampling method is a simple and practical technique to quantify an uncertainty (standard deviation) of the target parameter calculated by a core analysis code. It is noted that a statistical error is inevitably included in the estimated uncertainty because of the probabilistic method using random numbers. In order to estimate the statistical error of uncertainty, we focus on the bootstrap method. The bootstrap method is one of the resampling techniques to evaluate variance and confidence interval of a sample estimate (e.g. variance) without the assumption of normality. Through a lattice burnup calculation for a simplified boiling water reactor (BWR) fuel assembly, it is verified that the bootstrap method can reasonably estimate the confidence interval of uncertainty of infinite neutron multiplication factor (kinf) due to covariance data of JENDL-4.0. In the case of this problem, the distribution of kinf is well approximated by a normal distribution; thus, the confidence interval of uncertainty can be also estimated by the aid of chi-squared distribution. The merit using the bootstrap method is to simply estimate the confidence interval of uncertainty without the assumption of normality. © 2015 Atomic Energy Society of Japan. All rights reserved.


Murata T.,Physics and Energy Engineering | Hieda J.,Physics and Energy Engineering | Saito N.,Physics and Energy Engineering | Takai O.,Physics and Energy Engineering
Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi/Journal of the Ceramic Society of Japan | Year: 2011

MgF2 porous nanoparticle coatings with SiO2 binder were formed on glasssubstrates by solgel method. The samples were exposed to fluoro-alkyl silane (FAS) vapor and heated at 150°C to give water repellency. We measured surface roughnesses and static contact angles of water of the samples and examined the relation between surface roughnesses and contact angles. Scanning Probe Microscopy (SPM) confirmed that the FAS treatment had no effect on the surfaceroughness. In the autoclave temperature region of 100180° C, the higher the autoclave temperaturewas, the larger the surface roughness was. The sample prepared from the 100°C autoclaved sol had the minimum surface roughness of 4.1 nm and showed the minimum static contact angle of 115°. On the other hand, the sample prepared from the 180°C autoclaved sol had the maximum surface roughness of 9.5 nm and showed the maximum static contact angle of 134°. © 2011 The CeramicSociety of Japan.

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