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Kawasuso, Atsuo; Arashima, Hironobu*; Maekawa, Masaki; Ito, Hideaki*; Kabutomori, Toshiki*
Journal of Alloys and Compounds, 486(1-2), p.278 - 283, 2009/06
Times Cited Count:9 Percentile:48.27(Chemistry, Physical)We have studied the degradation process of TiCrV hydrogen storage alloy alloy using positron annihilation spectroscopy. As the hydrogen storage capacity decreased with the number of pressure swing cycles, positron lifetime increased. The increase in positron lifetime is due to the volume expansion caused by hydride formation. After degassing at 500 C, the hydrogen storage capacity recovered to the initial level. However, the positron lifetime was still longer than the initial level suggesting the survival of dislocations. The degradation of hydrogen storage capacity is probably caused by both hydride formation and the generation of dislocations.
Kawasuso, Atsuo; Arashima, Hironobu*; Maekawa, Masaki; Ito, Hideaki*; Kabutomori, Toshiki*
Materials Science Forum, 607, p.122 - 124, 2008/11
Using positron lifetime spectroscopy, we examined the evolution of defects in the TiCrV alloy prepared by the arc-melting method during hydriding cycles. After one hydriding cycle dislocations were responsible for positron trapping. The dislocation-related lifetime showed no significant change with increasing the hydriding cycle suggesting that the dislocation density is well above the dynamic range of positron trapping rate. After 20 hydriding cycles, prolonged lifetime components (0.4-0.5 ns and 1.9-2 ns) were obtained. These lifetimes were nearly constant during the further hydriding cycles while their intensities increased. Vacancy defects were generated and slowly developed to microvoids during the hydriding cycles. After 200 hydriding cycles the rechargeable hydrogen capacity decreased to 90% relative to the initial amount. It is thus inferred that the reduction of rechargeable hydrogen capacity is partly caused by the formation of microvoids and dislocations.
Fujimoto, Hirofumi*; Pinak, M.; Nemoto, Toshiyuki*; O'Neill, P.*; Kume, Etsuo; Saito, Kimiaki; Maekawa, Hideaki*
Journal of Computational Chemistry, 26(8), p.788 - 798, 2005/06
Times Cited Count:23 Percentile:57.44(Chemistry, Multidisciplinary)Clustered DNA damage sites induced by ionizing radiation have been suggested to have serious consequences to organisms. In this study, approaches based on molecular dynamics (MD) simulation have been applied to examine conformational changes and energetic properties of DNA molecules containing clustered damage sites consisting of 2 lesioned sites, 8-oxoG and AP site. After 1 nanosecond of MD simulation, one of the 6 DNA molecules containing a clustered damage site develop specific characteristic features: sharp bending at the lesioned site and weakening or complete loss of electrostatic interaction energy between 8-oxoG and bases locating on the complementary strand. From these results it is suggested that these changes would make it difficult for the repair enzyme to bind to the lesions within the clustered damage site and thereby result in a reduction of its repair capacity.
; Iijima, Tsutomu; ; ; ; ; ; ; ;
JAERI-M 9057, 25 Pages, 1980/09
no abstracts in English
Iijima, Tsutomu; ; ; ; ; ; ; ; ; ; et al.
JAERI-M 7887, 48 Pages, 1978/10
no abstracts in English
Matsue, Hideaki; Kasugai, Yoshimi; Harada, Masahide; Maekawa, Fujio; Kubo, Kenya*; Saito, Tsutomu*
no journal, ,
no abstracts in English
Kawasuso, Atsuo; Maekawa, Masaki; Arashima, Hironobu*; Ito, Hideaki*; Kabutomori, Toshiki*
no journal, ,
no abstracts in English