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Fujimoto, Shinji*; Tsuchiya, Hiroaki*; Ogawa, Soma*; Iida, Yoshihisa; Taniguchi, Naoki
Materials and Corrosion, 72(1-2), p.333 - 338, 2021/01
Times Cited Count：3 Percentile：12.73(Materials Science, Multidisciplinary)The stress corrosion cracking (SCC) of pure copper in bentonite was examined by a slow strain rate test (SSRT). The bentonite was swollen with pure water or aqueous solutions containing NH
of 0.05 M and 0.1 M. The thick corrosion films and particulate deposits were formed on copper surface after SSRT. Typical tarnish rupture type SCC occurred on pure copper in swollen bentonite with and without NH. Crack propagation rate was enhanced by NH. It is confirmed thick oxide layer is formed on copper during plastic deformation which resulting in the tarnish crack type SCC. The many particulate deposits observed on the surface might be formed as a results of rapid dissolution of Cu
to form porous CuO at locallized deformed sites.
-gas exposure at high temperaturesTakeda, Yusuke; Iida, Kiyoshi*; Sato, Shinji*; Matsuo, Tadatoshi*; Nagashima, Yasuyuki*; Okubo, Nariaki; Kondo, Keietsu; Hirade, Tetsuya
JPS Conference Proceedings (Internet), 25, p.011023_1 - 011023_3, 2019/03
In this study, we prepared samples under two different conditions, (1) 810
C, for 600 min, and (2) 850C, for 720 min. A depth-profile analysis of the surfaces of the samples is conducted through Doppler broadening (DB) measurements of positron annihilation 
rays using a slow positron beam. It was indicated that many of positrons annihilated in defects near the surface. According to the TEM image, there are nano-crystal grains near the surface and then positrons can diffuse in the grains and annihilate in defects at the grain boundaries. Furthermore, DB measurements indicated that there is a depth dependence on the chemical composition where positrons annihilate. EDS spectroscopy measurements also indicated that there is a depth dependence of impurities such as Vanadium. These results indicated change of the chemical composition at the grain boundaries.
-gas exposure at high temperaturesTakeda, Yusuke; Iida, Kiyoshi*; Sato, Shinji*; Matsuo, Tadatoshi*; Nagashima, Yasuyuki*; Okubo, Nariaki; Kondo, Keietsu; Hirade, Tetsuya
Journal of Physics; Conference Series, 791(1), p.012022_1 - 012022_4, 2017/02
Times Cited Count：1 Percentile：42.05(Physics, Multidisciplinary)Titanium alloy is widely used for applications such as golf club heads and structural materials for aircrafts. The surface can be exceedingly hardened by nitriding treatment that initiates defects, but there are some difficulties on use of titanium nitride because the layer can be exfoliated by stress. Therefore, we prepared samples in two different treatment conditions, (1) 810C 600 min and (2) 850C 720 min and performed depth profile analysis of Doppler broadening of positron annihilation -rays (DB) for these samples. According to a calculation of nitrogen diffusion depth, the nitride layer should be only about 0.05-0.1
m. However, the depth profile analysis of the DB measurement indicated that the defects introduced by nitriding treatment extended to a depth of 0.5m.
Iida, Yasuhiko*; Hanaoka, Hirofumi*; Watanabe, Satoshi; Watanabe, Shigeki; Ishioka, Noriko; Yoshioka, Hiroki*; Yamamoto, Shinji*; Paudyal, P.*; Paudyal, B.*; Higuchi, Tetsuya*; et al.
JAEA-Review 2009-041, JAEA Takasaki Annual Report 2008, P. 108, 2009/12
Yonehara, Hidenori*; Ishimori, Yuu; Akiba, Suminori*; Iida, Takao*; Iimoto, Takeshi*; Kai, Michiaki*; Shimo, Michikuni*; Tokonami, Shinji*; Yamada, Yuji*; Yoshinaga, Shinji*; et al.
Hoken Butsuri, 42(3), p.201 - 213, 2007/09
The pooled analysis recently carried out in European countries and North American countries showed the excess relative risk of lung cancer increased by 10-20% per 100 Bqm
increase in indoor radon concentration. The Scientific Committee on Indoor Radon Risk and Response to the Issue established by the Japan Health Physic Society reviewed the scientific evidence on the indoor radon risk obtained so far and evaluated the pooled analysis results from the viewpoint of estimating the risk coefficient in Japan. The committee concludes that the risk shown by the pooled analysis results has the consistency from miners risk analysis, and that it is probably not low in the reliability and validity, although the value may include the uncertainties caused from the correction of radon concentration measured, from the effect of thoron on measurement results, from the differences of environmental parameters in exposure, and so on.
O-BO melts and glassesUmesaki, Norimasa*; Kita, Y.*; Iida, T.*; Handa, K.*; Kohara, Shinji*; Suzuya, Kentaro; Fukunaga, Toshiharu*; Misawa, Masakatsu*
Physics and Chemistry of Glasses, 41(5), p.304 - 308, 2000/10
no abstracts in English
O-BO glasses and meltsUmesaki, Norimasa*; Kita, Y.*; Handa, K.*; Kohara, Shinji*; Suzuya, Kentaro; Fukunaga, T.*; Misawa, M.*; Iida, T.*
Denki Kagaku Oyobi Kogyo Butsuri Kagaku, 67(6), p.541 - 546, 1999/00
no abstracts in English
O-BO (M: Na and K) glasses and melts by neutron diffractionHanda, K.*; Kita, Y.*; Kohara, Shinji*; Suzuya, Kentaro; Fukunaga, Toshiharu*; Misawa, Masakatsu*; Iida, T.*; *; Umesaki, Norimasa*
Journal of Physics and Chemistry of Solids, 60(8-9), p.1465 - 1471, 1999/00
Times Cited Count：16 Percentile：64.83(Chemistry, Multidisciplinary)no abstracts in English
Yamasaki, Keizo*; Oki, Yuichi*; Osada, Naoyuki*; Yokoyama, Sumi; Yamada, Yuji*; Tokonami, Shinji*; Fukutsu, Kumiko*; Iida, Takao*; Rahman, N. M.*; Shimo, Michikuni*
no journal, ,
no abstracts in English
Yamasaki, Keizo*; Oki, Yuichi*; Osada, Naoyuki*; Iida, Takao*; Shimo, Michikuni*; Yamada, Yuji*; Tokonami, Shinji*; Fukutsu, Kumiko*; Yokoyama, Sumi
no journal, ,
The physicochemical properties of radioactive aerosols are important factors to assess internal dose at high energy accelerator facilities. In Kyoto University Research Reactor Institute, a generation of radioactive aerosols in ADSR (Accelerator-Driven Subcritical Reactor) facilities was studied as part of the research project of ADSR. The generation of radioactive aerosols in high intensity irradiation fields of ADSR was simulated by irradiation of the target room air at LINAC. We measured the particle size of radioactive aerosols in the target room during the acceleration period. Natural radon aerosols in the target room grew to the larger size because of an attachment of radon daughters to non-radioactive aerosols. The particle size of the produced radioactive aerosols was also larger with time. This would mean that a formation mechanism of the radioactive aerosols produced at high energy accelerator facilities is the same as radon one.
Izumi, Keisuke*; Iguchi, Masayuki*; Iida, Shinji*; Kawasaki, Masaji*; Okawa, Yoshinao*; Oka, Kiyoshi; Yamagata, Ryohei
no journal, ,
no abstracts in English
Takeda, Yusuke; Iida, Kiyoshi*; Sato, Shinji*; Matsuo, Tadatoshi*; Nagashima, Yasuyuki*; Okubo, Nariaki; Kondo, Keietsu; Hirade, Tetsuya
no journal, ,
The impact stress exfoliates a Nitride surface layer on Titanium alloy prepared in some conditions. So we prepared specimens in two different conditions, (1) 810C, 600min and (2) 850C, 720min, and performed depth profile analysis of their surfaces with Doppler broadening measurements of positron annihilation -rays (DB) that is sensitive for defects by Slow Positron beams. Although the specimens (2) is harder than (1) according to the Vickers Hardness test, DB results indicated that defect layer of specimen (1) is thicker than (2). It means that the defect layer thickness was not the cause of surface hardening. Furthermore, chemical elements at the positron annihilation sites could be analyzed qualitatively by DB and the change of the composition appeared in deeper region than the defect layer. The defect layer depth does not match the depth where chemical composition changes by DB appeared. TEM and EDS observation showed different tendency from the results by DB. It is because positrons probe specific sites, and the combination of these methods will be a strong tool to investigate surface structures.
Nishimura, Kazuaki; Tanaka, Hideki; Kobayashi, Daisuke; Suzuki, Shohei; Numata, Shinji; Nakamichi, Hideo; Kurita, Tsutomu; Iida, Masayoshi*; Tajiri, Kazuma*; Sukegawa, Katsumi*
no journal, ,
no abstracts in English
Numata, Shinji; Isomae, Hidemi; Omura, Masami; Tsutagi, Koichi; Kobayashi, Daisuke; Nakamura, Daishi; Nemoto, Masahiro; Iida, Masayoshi*; Tajiri, Kazuma*; Kurita, Tsutomu
no journal, ,
no abstracts in English
