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Matsuhashi, Shimpei; Hanaoka, Hirofumi*; Takasaki, Koji; Hakoda, Teruyuki; Endo, Keigo*; Ishioka, Noriko
no journal, ,
no abstracts in English
Mochizuki, Izumi; Fukaya, Yuki; Kawasuso, Atsuo
no journal, ,
Defect-free quasi one dimensional (1D) chain of single-atom wide is reconstructed on the Ge(001) crystal surface by the adsorption of Pt atoms with sub-atomic layer. While it is required that the elucidation of the electronic properties for the 1D metal or the Peierls transition about 80 K, it is not yet fully understood about the atomic arrangement and the displacement in the phase transition. We have reported that the experimentally obtained rocking curve of a one-beam condition using reflection high-energy positron diffraction (RHEPD) matches the calculated curve assuming the Nano-Wire (NW) model suggested by Vanpoucke et al. However, they have also proposed several NW models with different Pt coverage and have argued the phase transition derives from the change of the Pt coverage. In this study, we tried to get determined the certain atomic arrangement, the Pt coverage and the displacement in the transition on the Pt/Ge(001) surface from the RHEPD analysis with a many-beam condition (MBC). The rocking curve of the MBC shows a good agreement with the calculated curve assuming the NW model with the Pt coverage of 0.75 ML, while the curve does not agree with the curves calculated from the Pt coverage of 0.8125 or 0.875 ML. Thus, Pt coverage of the Pt/Ge(001) surface is 0.75 ML as found reasonable. In addition, the change of rocking curves in comparison of before and after the transition shows the result suggesting the structural phase transition caused by the height difference of the topmost Ge dimer atoms with no variance of the Pt coverage.
Kawasuso, Atsuo; Maekawa, Masaki; Fukaya, Yuki; Yabuuchi, Atsushi; Mochizuki, Izumi
no journal, ,
no abstracts in English
Zn and 
CdSuzui, Nobuo; Yamazaki, Haruaki; Ishii, Satomi; Kawachi, Naoki; Fujimaki, Shu
no journal, ,
no abstracts in English
C-labeled photoassimilateYamazaki, Haruaki; Suzui, Nobuo; Kawachi, Naoki; Ishii, Satomi; Shimada, Hiroaki*; Fujimaki, Shu
no journal, ,
no abstracts in English
Maekawa, Masaki; Kawasuso, Atsuo; Fukaya, Yuki; Yabuuchi, Atsushi; Mochizuki, Izumi
no journal, ,
no abstracts in English
Fukaya, Yuki; Maekawa, Masaki; Wada, Ken*; Hyodo, Toshio*; Kawasuso, Atsuo
no journal, ,
no abstracts in English
Yabuuchi, Atsushi; Maekawa, Masaki; Kawasuso, Atsuo
no journal, ,
Recently, a new hypothesis about the crack propagation mechanism of the stress corrosion cracking occurred in the high temperature water has been proposed. The hypothesis is that the decrease in the grain boundary binding energy due to the inflow of vacancies causes the crack propagation. To investigate the effects of respective SCC occurrence factors on vacancy formation, in the present study, the sensitization heat treatment, the corrosion treatment and the tensile plastic deformation, which were three SCC factors, were investigated using Type 304 stainless steels. The results revealed that the sensitization-heat-treatment-induced and the tensile-deformation-induced vacancies were identified as monovacancies because of their thermal stability. The vacancies in both samples start to migrate at 200 
C, and finish recovering at 400 C. This temperature range corresponds to the recovery range of the electron-irradiation-induced monovacancies.
produced in water radiolysisYamashita, Shinichi; Katsumura, Yosuke; Hiroishi, Daisuke*; Murakami, Takeshi*
no journal, ,
Yield of dihydrogen molecule (H) produced in water radiolysis is important for safety management in nuclear industry including water chemistry in nuclear fission reactors as well as for investigation of very early stages of radiation-induced phenomena, which are closely related to spatial distribution of energy deposition from charged particle to surrounding matter. A new apparatus for online measurements of H produced in water radiolysis, and the apparatus was utilized for 
-irradiation. By improving tubing between a sample cell and thermal conductivity detector, which are settled inside and outside the irradiation room, respectively, sensitivity and accuracy of the system has much improved and resultant H yield was almost same as those reported in literatures.
-radiolysis of boric acid solutionSuzuki, Baku*; Yamashita, Shinichi; Katsumura, Yosuke
no journal, ,
Excess power in pressurized water reactor is controlled by addition of boric acid so that a 
B atom in boric acid captures a thermal neutron which would induce further chain nuclear fission reactions if it is not captured. In this case, not only radiations pertaining to nuclear fission reactions but also 
-ray and low-energy Li ion generated in the neutron capture reactions decompose water, leading to production of highly reactive water decomposition radicals. In order to comprehend water chemistry inside the reactors, effects of all of the radiations must be understood. Before investigating the neutron capture radiations from B, it should be studied what kind of chemical effects are given by the addition of boric acid. In this work, the addition of boric acid was studied with the Fricke dosimeter.
, Br
and Br
in aqueous solutionsLin, M.; Muroya, Yusa*; Katsumura, Yosuke*; Archirel, P.*; Van-Oanh, N. T.*; Fu, H.*; Yan, Y.*; Nagaishi, Ryuji; Kumagai, Yuta; Mostafavi, M.*
no journal, ,
The absorption spectra of Br and Br in aqueous solutions are investigated by pulse radiolysis techniques from room temperature to 380 and 350C, respectively. The weak temperature effect on the absorption spectra of Br and Br is because in these two systems, the transition occurs between two valence states. We performed classical dynamics of hydrated Br system at 20 and 300C under pressure of 25 MPa. This shows that the first water shell is strongly bound to the anion whatever the temperature. The first two water shells form a cavity of a roughly spherical shape around the anion. By TDDFT method, we calculated the absorption spectra of hydrated Br at two temperatures and we compared the results with the experimental data.
BrWatanabe, Satoshi; Watanabe, Shigeki; Iida, Yasuhiko*; Hanaoka, Hirofumi*; Endo, Keigo*; Ishioka, Noriko
no journal, ,
no abstracts in English
I-Sansalvamide AWatanabe, Shigeki; Tsukui, Narutaka; Hanaoka, Hirofumi*; Yamada, Keiichi*; Ohshima, Yasuhiro; Iida, Yasuhiko*; Endo, Keigo*; Ishioka, Noriko
no journal, ,
no abstracts in English
Hirade, Tetsuya; Oka, Toshitaka; Morishita, Norio*; Idesaki, Akira; Shimada, Akihiko
no journal, ,
The triplet positronium (ortho-positronium), bound state of positron and electron, have been used to investigate microscopic free volume of polymers. We have shown that the free positron annihilation lifetime also can be used to investage the microscopic free volume of polymers, especially for non-positronium forming polyimides, such as kapton. Here we applied this method to study electron and irradiation effects. Electron beam irradiation produce cross-linking and the irradiation produce cross-linking and chain scission. Free volume change for electron irradiation could reproduce the change on the mechanical properties. However, That for irradiation could not reproduce the change on the mechanical properties, because the degradation process was not simple.
Kikuchi, Masahiro; Kameya, Hiromi*; Shimoyama, Yuhei; Todoriki, Setsuko*; Ukai, Mitsuko*; Kobayashi, Yasuhiko
no journal, ,
no abstracts in English
ray irradiated foodKaimori, Yoshihiko; Sakamoto, Yuki*; Nakamura, Hideo*; Kikuchi, Masahiro; Ukai, Mitsuko*; Shimoyama, Yuhei; Kobayashi, Yasuhiko
no journal, ,
no abstracts in English
Furukawa, Jun*; Iwata, Yoshiaki*; Suzui, Nobuo; Ishii, Satomi; Kawachi, Naoki; Yamazaki, Haruaki; Fujimaki, Shu; Sato, Shinobu*
no journal, ,
no abstracts in English