Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Ishizawa, Akihiro*; Idomura, Yasuhiro; Imadera, Kenji*; Kasuya, Naohiro*; Kanno, Ryutaro*; Satake, Shinsuke*; Tatsuno, Tomoya*; Nakata, Motoki*; Nunami, Masanori*; Maeyama, Shinya*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 92(3), p.157 - 210, 2016/03
The high-performance computer system Helios which is located at The Computational Simulation Centre (CSC) in The International Fusion Energy Research Centre (IFERC) started its operation in January 2012 under the Broader Approach (BA) agreement between Japan and the EU. The Helios system has been used for magnetised fusion related simulation studies in the EU and Japan and has kept high average usage rate. As a result, the Helios system has contributed to many research products in a wide range of research areas from core plasma physics to reactor material and reactor engineering. This project review gives a short catalogue of domestic simulation research projects. First, we outline the IFERC-CSC project. After that, shown are objectives of the research projects, numerical schemes used in simulation codes, obtained results and necessary computations in future.
X, 2; How to use itOka, Toshitaka; Ito, Kenji*
Hoshasen Kagaku (Internet), (93), p.57 - 61, 2012/03
no abstracts in English
Oka, Toshitaka; Ito, Kenji*
Hoshasen Kagaku (Internet), (92), p.51 - 53, 2011/09
no abstracts in English
Ata, Seisuke*; Oka, Toshitaka; He, C.-Q.*; Odaira, Toshiyuki*; Suzuki, Ryoichi*; Ito, Kenji*; Kobayashi, Yoshinori*; Ougizawa, Toshiaki*
Journal of Polymer Science, Part B; Polymer Physics, 48(20), p.2148 - 2153, 2010/10
Times Cited Count：6 Percentile：20.18(Polymer Science)Surface morphology of bisphenol-A polycarbonate (BAPC) thin films with thickness ranging from 30 to 1000 nm on silicon substrates was studied by atomic force microscopy (AFM). The films were prepared by spincasting from 1,2-dichloroethane solutions of 0.25-5.0 wt % BAPC. Even though longer annealing than 250 h was necessary for complete crystallization for bulk BAPC, high crystallinity was observed for 30 nm thick film after annealing at 200 
C for 48 h in vacuum. Positron annihilation lifetime spectroscopy (PALS) measurements showed that the free volume hole size in 30 nm thick film was larger than that of bulk at 200 C. Comparison of the BAPC concentration in the precursor solution with the overlap concentration suggests that the high crystallinity of the 30 nm BAPC film is due to less entangled chains caused by rapid removal of the solvent from the dilute solution.
Ito, Kenji*; Oka, Toshitaka*; Kobayashi, Yoshinori*; Shirai, Yasuharu*; Wada, Kenichiro*; Matsumoto, Masataka*; Fujinami, Masanori*; Hirade, Tetsuya; Honda, Yoshihide*; Hosomi, Hiroyuki*; et al.
Materials Science Forum, 607, p.248 - 250, 2009/00
So far no standard procedure for the positron annihilation lifetime (PAL) technique has been established. A lack of the standards has led to difficulty in ensuring the equivalency and reliability of data from different laboratories. As a first, we conducted an interlaboratory comparison of PAL measurements for metal, polymer and silica glass with agreed procedures for data recording and analysis. The PAL data recorded at different laboratories were analyzed with a single lifetime component for the metal sample and with three components for the others, respectively. Based on the results of the reported positron and ortho-positronium lifetimes, the possible sources of the uncertainties in the PAL measurements are discussed. To reduce the effect of scattered 
rays, a lead shield was placed between the detectors. The uncertainty was significantly decreased, signifying that placing lead shields between the detectors effectively reduced the false signals due to the scattered rays.
Ito, Kenji*; Oka, Toshitaka*; Kobayashi, Yoshinori*; Shirai, Yasuharu*; Wada, Kenichiro*; Matsumoto, Masataka*; Fujinami, Masanori*; Hirade, Tetsuya; Honda, Yoshihide*; Hosomi, Hiroyuki*; et al.
Journal of Applied Physics, 104(2), p.026102_1 - 026102_3, 2008/07
Times Cited Count：48 Percentile：83.47(Physics, Applied)Interlaboratory comparison of positron annihilation lifetime measurements using synthetic fused silica and polycarbonate was conducted with the participation of 12 laboratories. By regulating procedures for the measurement and data analysis the uncertainties of the positron lifetimes obtained at different laboratories were significantly reduced in comparison with those reported in the past.
Oshima, Takeshi; Uedono, Akira*; Eryu, Osamu*; Lee, K. K.; Abe, Koji*; Ito, Hisayoshi; Nakashima, Kenshiro*
Materials Science Forum, 433-436, p.633 - 636, 2003/08
no abstracts in English
Oshima, Takeshi; Uedono, Akira*; Abe, Hiroshi; Chen, Z. Q.*; Ito, Hisayoshi; Yoshikawa, Masahito; Abe, Koji*; Eryu, Osamu*; Nakashima, Kenshiro*
Physica B; Condensed Matter, 308-310, p.652 - 655, 2001/12
Times Cited Count：6 Percentile：37.48(Physics, Condensed Matter)Co-implantation of Al(2E18/cm3) and C(1E18/cm3) into 6H-SiC and subsequent thermal annealing up to 1650 C werer carried out. Vacancy-type defects in the implanted layer were studied by monoenergetic positron beams. The mean size of vacancy-type defects in as-implanted samples is found to be close to the size of divacancy. Although vacancy clsters near a surface region were created by 1000 C-annealing, clustering is suppressed in a deep region.The mean size of vacancys decrease by annealing above 1000 C, and major vacancy defects annealed out after annealing at 1400 C. No significant difference in defect annealing between only Al- and co-implanted samles was observed.This result suggests that electrical activation of Al is enhanced by the site competition mechanism.
Kobayashi, Yoshinori*; Ito, Kenji*; Oka, Toshitaka*; Sakaki, Koji*; Shirai, Yasuharu*; Honda, Yoshihide*; Shimazu, Akira*; Fujinami, Masanori*; Hirade, Tetsuya; Saito, Haruo*; et al.
no journal, ,
For making a standard sample of positron annihilation measurement, quartz glass and polycarbonate were measured with 12 apparatus at AIST, Chiba Univ., Tokyo Univ., Tsukuba Univ., Touhoku Univ., Tokyo Gakugei Univ. JAEA, Nitto Denko, and Toray Research Center. By regulating procedure for the measurement and data analysis the uncertainties of the positron annihilation lifetime obtained at different laboratories were significantly reduced.
Ito, Kenji*; Oka, Toshitaka*; Kobayashi, Yoshinori*; Shirai, Yasuharu*; Wada, Kenichiro*; Matsumoto, Masataka*; Fujinami, Masanori*; Hirade, Tetsuya; Honda, Yoshihide*; Hosomi, Hiroyuki*; et al.
no journal, ,
So far no standard procedure for the positron annihilation lifetime (PAL) technique has been established. A lack of the standards has led to difficulty in ensuring equivalency and reliability of data from different laboratories. Recently, as a first step toward the standardization of the PAL technique, we conducted an interlaboratory comparison of PAL measurements for fused silica, polycarbonate and metal with agreed procedures for data recording and analysis. Based on the results of the reported lifetimes, possible sources of the uncertainties in the PAL measurements is probably caused by the backscattered -rays by other detectors. We succeeded to show that inserting shields between detectors can reduce the uncertainty.
Ito, Kenji*; Oka, Toshitaka*; Kobayashi, Yoshinori*; Shirai, Yasuharu*; Wada, Kenichiro*; Matsumoto, Masataka*; Fujinami, Masanori*; Hirade, Tetsuya; Honda, Yoshihide*; Hosomi, Hiroyuki*; et al.
no journal, ,
An interlaboratory comparison for positron annihilation lifetime measurements for pure nickel, polycarbonate (PC) and fused silica was performed. Based on the reported data of positron (for nickel) and positronium (for PC and fused silica) components, the uncertainties in the PAL measurements were estimated and their possible source was discussed.
Jiang, L.*; O'Rourke, B. E.*; Harada, Yoshihisa*; Takatsu, Shuhei*; Ito, Kenji*; Okubo, Masataka*; Hirade, Tetsuya; Uedono, Akira*; Suzuki, Ryoichi*; Takai, Kenichi*; et al.
no journal, ,
We are studying the depth dependence of the density of the defects induced by the electrical discharge machining (EDM) in SUS316L, using the electron probe microanalysis (EPMA), Positron annihilation lifetime spectroscopy (PALS) and X-ray diffraction (XRD). EPMA results show a large change in the composition over the first 10 
m. This layer can be assumed to correspond to the recast layer. PALS and XRD results suggest a defect layer with a thickness of around 50 m. This depth can be assumed to correspond to the heat affected zone where dislocations and vacancy clusters exists. For PALS (and other methods) analysis, it is recommended to remove the topmost 100 m of the samples by chemical polishing after EDM.
Ito, Satoshi; Sano, Kyohei; Tameta, Yuito; Akiyama, Kazuki
no journal, ,
The High Active Solid Waste store HASWS of Tokai Reprocessing Plant. HASWS don't have a equipment to retrieve the High Active Solid Waste. Therefore, I examined the Using remotely machine at decommissioning of domestic and international. In the technical investigation, I investigated the machine and others which could perform work of (1)-(3). (1) Cutting work of the wire attached to Hull Can. (2) Moving work of Hull Can. (3) Attach the hoisting accessory work of Hull Can. I compared the extracting machine and others. As a result, I chosed the Remotely operated Vehicle And underwater buoyancy.
Tameta, Yuito; Sano, Kyohei; Ito, Satoshi; Akiyama, Kazuki
no journal, ,
We are developing a system to take out waste from wet storage for the decommissioning of HASWS in Tokai Reprocessing Plant. The main component of the system is an underwater ROV, which has been used for decommissioning in the U.K. However, since the underwater ROV alone cannot handle the waste, we are considering combining it with an underwater buoyancy, which is used for lifting and transporting submarine items in the offshore field. In mock-up tests, simulated waste has been placed in a mock-up facility that simulates an actual HASWS, and tests have been conducted to lift up simulated waste using various shapes of underwater buoyancy and to move simulated waste by combining an underwater ROV and an underwater lifter. We report the results of these tests, as we obtained results regarding the removal of waste using underwater buoyancy.
Sano, Kyohei; Tameta, Yuito; Ito, Satoshi; Akiyama, Kazuki
no journal, ,
Toward the decommissioning of HASWS in Tokai Reprocessing Plant, we are developing equipment for recovery waste from wet storage. So far, after conducting surveys and operability confirmations of ROVs that have been used for decommissioning in the UK, we have conducted mock-up trials using an ROV tester. In the mock-up trial, simulated waste was placed in various postures and orientations in a mock-up facility simulating the HASWS. We confirmed that the ROV could cut the wires attached to the waste, that the waste could be moved using the underwater ROV and buoyancy, and that the ROV could attach hanging tools to the waste. A result was obtained regarding the removal of waste using an underwater ROV, etc., so I will report it.
