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Mochizuki, Izumi; Fukaya, Yuki; Kawasuso, Atsuo
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 137, 2012/01
Defect-free quasi-one chain with the single atomic width is reconstructed on the Ge(001) surface by a Pt adsorption of sub-atomic layer. Recently, it has been reported that the atomic chain undergoes the Peierls transition about 80 K. But, the electronic property, the atomic arrangements and displacements in the phase transition are not yet elucidated. Using reflection high-energy positron diffraction (RHEPD), we have reported that the rocking curve in a one-beam condition matches the dynamical calculation assuming the Nano-Wire (NW) model suggested by Vanpoucke et al. However, they have also proposed several NW models with different Pt coverages and have argued that the phase transition derives from the change of the Pt coverage. In this study, we have tried to determine the atomic arrangement, the Pt coverage and the displacements in the phase transition by using RHEPD with a many-beam condition. The rocking curve 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 from the Pt coverage of 0.8125 or 0.875 ML. In addition, the change of rocking curves in the phase transition shows that the structural phase transition is caused by the height difference of the topmost Ge dimer atoms making the p(4
4) structure.
Mohamed, N. H.*; Tamada, Masao; Ueki, Yuji; Seko, Noriaki
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 45, 2012/01
no abstracts in English
Ueki, Yuji; Dafader, N. C.*; Seko, Noriaki; Tamada, Masao
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 43, 2012/01
no abstracts in English
Mizote, Norihito*; Saito, Hiroaki*; Ueki, Yuji; Seko, Noriaki; Tamada, Masao
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 52, 2012/01
no abstracts in English
Saiki, Seiichi; Puspitasari, T.*; Seko, Noriaki
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 44, 2012/01
no abstracts in English
Aihara, Jun; Maekawa, Masaki; Ueta, Shohei; Kawasuso, Atsuo; Sawa, Kazuhiro
no journal, ,
The Japan Atomic Energy Agency has developed the evaluation methods of stoichiometry and density of ZrC layers as well as the coating technology of the ZrC layers for advanced high temperature gas-cooled reactors, however, there were the batches of which ZrC crystal grain sizes, after the heat treatment for the simulation of the sintering process of the fuel compacts, were different from each other in spite of the same stoichiometry and ZrC density. Then the positron annihilation spectroscopy (PAS) measurements, which is proper for the quantitative evaluation of the specimens and it is easy to prepare the specimens for, of the coating layers were carried out with the positron microscope developed by JAEA. The difference in these batches was detected with PAS. The density of the vacancy type defects in the ZrC layer in the batch, in which remarkable ZrC crystal grain growth occurred with the heat treatment, was estimated to be smaller than another batch.
Shikaze, Yoshiaki; Tanimura, Yoshihiko; Tsutsumi, Masahiro; Yoshizawa, Michio; Harano, Hideki*; Matsumoto, Tetsuro*; Mizuhashi, Kiyoshi
no journal, ,
no abstracts in English
Naito, Hiroyuki; Itagaki, Wataru; Okazaki, Yoshihiro; Imaizumi, Kazuyuki; Kitamura, Ryoichi; Shamoto, Naoki*; Takeshima, Yoshiyuki*
no journal, ,
no abstracts in English
Hiroki, Akihiro; Sato, Toshihiro*; Nagasawa, Naotsugu; Taguchi, Mitsumasa; Tamada, Masao
no journal, ,
Preparation of HPC hydrogels with good mechanical properties as well as transparency was investigated. The modified HPC hydrogels were prepared by electron beam irradiation to highly concentrated aqueous solutions containing HPC, tricosaethylene glycol dimethacrylate (23G) and 2-hydroxy methacrylate (HEMA). The addition of 23G with HPC induced the increase in the gel fraction, especially at less than 20 kGy. It was found that the gel fraction of the HPC/23G/HEMA hydrogel decreased drastically. Tensile strength and elongation at break of HPC/HEMA/23G hydrogel (20/2.0/0.2 wt%) obtained at 50 kGy were 2.0 kg/cm
and 124%, which exhibited about 2.0 and 1.8 times larger than these of the pure HPC hydrogel, respectively. Therefore, the HPC hydrogels with desired properties were obtained by radiation crosslinking HPC with monomers.
BrWatanabe, Satoshi; Watanabe, Shigeki; Iida, Yasuhiko*; Hanaoka, Hirofumi*; Endo, Keigo*; Ishioka, Noriko
no journal, ,
no abstracts in English
Seguchi, Tadao*
no journal, ,
The degradation mechanisms of polymer materials as PE, EPR for cable insulations in a nuclear power plant were studied by accelerated thermal and radiation ageing. The contribution of stabilizers to polymer degradation was investigated by the measurements of oxidation products, content of stabilizers, and also mechanical properties. It was found that an antioxidant among the stabilizers was very effective to decrease the thermal oxidation but less effective to the radiation induced oxidation. The content of the antioxidant decreases by evaporation during thermal ageing and by decomposition with dose during radiation ageing. The new degradation mechanisms in polymer ageing are proposed.
-ray irradiation on solvent extraction of minor actinideSugo, Yumi; Taguchi, Mitsumasa; Sasaki, Yuji; Ishioka, Noriko; Morita, Yasuji
no journal, ,
no abstracts in English
Maekawa, Masaki; Kawasuso, Atsuo; Yabuuchi, Atsushi
no journal, ,
no abstracts in English
Br]bromo--methyl-L-tyrosine, a novel tyrosine analog for positron emission tomography imaging of tumorsOhshima, Yasuhiro; Hanaoka, Hirofumi*; Tominaga, Hideyuki*; Watanabe, Shigeki; Sugo, Yumi; Watanabe, Satoshi; Oriuchi, Noboru*; Endo, Keigo*; Ishioka, Noriko
no journal, ,
no abstracts in English
-ray irradiation to polyethylene, polystyrene and cellulose resinSaito, Kosuke
no journal, ,
At 23rd July 2010, a fire accident broke out in Plutonium Fuel Development Center (Pu Center), Tokai, JAEA. The fire was occurred from the cylindrical container of stainless steel in a glove box which loaded uranium and plutonium compounds. In order to clear up the cause of the fire, Pu Center studied it from all angles. For one of the possible causes, some inflammable gas and/or hydrogen gas were deduced to be generated from irradiated plastic cases and/or cellulose resin which are organic substances in the stainless container. The plastic cases, which were used to reposit nuclear materials, are made of both polyethylene (PE) and polystyrene (PS). The both polymer was known to be decomposed by -ray irradiation and generate hydrogen gas, whose quantitative evaluation as absorbed dose was reported. As for PE, other gases such as carbon oxides, methane and ethane are produced. Cellulose resin was used for binder of uranium nitride powder, but gas generation from cellulose resin by -ray irradiation has not been reported. Then, in order to demonstrate and investigate hydrogen and inflammable-gas generation from polymers and cellulose resins, -ray irradiation to the materials and analyses of the generated gaseous substances were performed.
Sato, Shinichiro; Oshima, Takeshi; Imaizumi, Mitsuru*
no journal, ,
no abstracts in English
Imaizumi, Mitsuru*; Saito, Masashi*; Yuri, Yosuke; Sato, Shinichiro; Oshima, Takeshi
no journal, ,
no abstracts in English
Okada, Hiroshi*; Wakahara, Akihiro*; Park, J.-H.*; Sato, Shinichiro; Oshima, Takeshi
no journal, ,
no abstracts in English
Nara, Takayuki; Ishibori, Ikuo; Kurashima, Satoshi; Yoshida, Kenichi; Yuyama, Takahiro; Ishizaka, Tomohisa; Yokota, Wataru; Okumura, Susumu; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; et al.
no journal, ,
no abstracts in English
, YAG:Ce and diamondOnoda, Shinobu; Makino, Takahiro; Oshima, Takeshi
no journal, ,
no abstracts in English
