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Watanabe, Masashi; Yokoyama, Keisuke; Imai, Yoshiyuki; Ueta, Shohei; Yan, X.
Ceramics International, 48(6), p.8706 - 8708, 2022/03
Times Cited Count：7 Percentile：75.06(Materials Science, Ceramics)Previous studies have used various methods for sintering of SiC, carbon, and SiC/carbon functionally graded materials (FGM). However, no experimental studies on SiC/graphite FGM manufacturing using the spark plasma sintering (SPS) method have been reported. In this study, a SiC/graphite FGM specimen has been fabricated using SPS. The interface between the adjacent layers of the sintered specimen exhibits no apparent defects such as gaps or delaminations. The SiC and graphite phases in the specimen show no substantial change before and after sintering.
Takeda, Tetsuaki*; Inagaki, Yoshiyuki; Aihara, Jun; Aoki, Takeshi; Fujiwara, Yusuke; Fukaya, Yuji; Goto, Minoru; Ho, H. Q.; Iigaki, Kazuhiko; Imai, Yoshiyuki; et al.
High Temperature Gas-Cooled Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.5, 464 Pages, 2021/02
As a general overview of the research and development of a High Temperature Gas-cooled Reactor (HTGR) in JAEA, this book describes the achievements by the High Temperature Engineering Test Reactor (HTTR) on the designs, key component technologies such as fuel, reactor internals, high temperature components, etc., and operational experience such as rise-to-power tests, high temperature operation at 950
C, safety demonstration tests, etc. In addition, based on the knowledge of the HTTR, the development of designs and component technologies such as high performance fuel, helium gas turbine and hydrogen production by IS process for commercial HTGRs are described. These results are very useful for the future development of HTGRs. This book is published as one of a series of technical books on fossil fuel and nuclear energy systems by the Power Energy Systems Division of the Japan Society of Mechanical Engineers.
Niizato, Tadafumi; Imai, Hisashi*; Maekawa, Keisuke; Yasue, Kenichi; Kurikami, Hiroshi; Shiozaki, Isao*; Yamashita, Ryo*
Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM), 10 Pages, 2011/10
A critical issue for building confidence in the long-term safety of geological disposal is to demonstrate the stability of the geosphere, taking into account its likely future evolution. This study aims to establish comprehensive techniques for characterising the overall evolution of coastal sites through studying the palaeohydrogeological evolution in the coastal system around the Horonobe area, Hokkaido, northern Japan. Information on natural events and processes related to the palaeohydrogelogical evolution of the area have been integrated into the conceptual models that indicates the temporal and spatial sequences of the events and processes, such as climatic and sea-level changes, palaeogeography, and geomorphological and geological evolution in the area. The groundwater flow simulation, which is based on the conceputualisation of the long-term geosphere evolution, shows the sensitivities of natural events and processes on groundwater flow properties in a coastal setting.
Tamada, Taro; Kinoshita, Takayoshi*; Kurihara, Kazuo; Adachi, Motoyasu; Ohara, Takashi; Imai, Keisuke*; Kuroki, Ryota; Tada, Toshiji*
Journal of the American Chemical Society, 131(31), p.11033 - 11040, 2009/07
Times Cited Count：58 Percentile：79.01(Chemistry, Multidisciplinary)To help resolve long-standing questions regarding the catalytic activity of the serine proteases the structure of porcine pancreatic elastase has been analyzed by high-resolution neutron and X-ray crystallography. In order to mimic the tetrahedral transition intermediate a peptidic inhibitor was used. A single large crystal was used to collect room-temperature neutron data to 1.65 
resolution and X-ray data to 1.20 resolution. Another crystal provided a low-temperature X-ray data set to 0.94 resolution. The neutron data are to higher resolution than previously reported for a serine protease and the X-ray data are comparable with other studies. The neutron and X-ray data show that the hydrogen bond between His57 and Asp102 (chymotrypsin numbering) is 2.60 in length and that the hydrogen-bonding hydrogen is 0.80-0.96 from the histidine nitrogen. This is not consistent with a low-barrier hydrogen which is predicted to have the hydrogen midway between the donor and acceptor atom. The observed interaction between His57 and Asp102 is essentially a short but conventional hydrogen bond, sometimes described as a short ionic hydrogen bond. The neutron analysis also shows that the oxygen of the oxopropyl group of the inhibitor is present as an oxygen anion rather than a hydroxyl group, supporting the role of the "oxyanion hole" in stabilizing the tetrahedral intermediate in catalysis.
Imai, Hisashi*; Yamashita, Ryo*; Shiozaki, Isao*; Urano, Kazuhiko*; Kasa, Hiroyoshi*; Maruyama, Yoshio*; Niizato, Tadafumi; Maekawa, Keisuke
JAEA-Research 2009-001, 116 Pages, 2009/03
JAEA-Research-2009-001.pdf:32.12MB
Evaluation of long-term geological evolution and its impact on groundwater flow is one of the major themes within the frame of Horonobe Underground Research Laboratory Project. For the purpose of development of a groundwater flow modeling methodology considering the effects of long-term geological evolution, following three items were studied: (1) Upgrade of SMS (Sequential Modeling System of geo-environmental evolution impact on groundwater flow) which was developed in 2006 FY; (2) Groundwater flow simulation under more realistic conditions of geological structures and hydrogeological conditions; and (3) Sensitivity study of geo-environmental evolution impacts on groundwater flow. The studies showed following suggestive results. (1) Development of a precise time step setting enabled to narrow the gaps in simulated head between time steps in which the model configuration used to deformed. (2) Several aspects have been found from studies on impact factors such as deposition on pore pressure, recharge rate and difference in density of saline groundwater. For evaluation of pore pressure induced by deposition, it is necessary to model the porosity and permeability variation considering the exceed pore pressure change. The setting of recharge rate during the Ice Age influence the characteristics of groundwater flow in coastal and hilly areas. The density of groundwater is not so influential as topological potential factors, however it is effective for the characteristics of groundwater flow in coastal area and intrusion of recharge water from ground surface. (3) The sensitivity study on faulting characteristics indicated that the two types of fault configuration and the hydraulic conductivity setting considered are not influential on the nature of groundwater flow above the depth of 500 m.
Kinoshita, Takayoshi*; Tamada, Taro; Imai, Keisuke*; Kurihara, Kazuo; Ohara, Takashi; Kuroki, Ryota
Acta Crystallographica Section F, 63(4), p.315 - 317, 2007/04
Times Cited Count：8 Percentile：66.54(Biochemical Research Methods)Porcine pancreatic elastase (PPE) resembles the attractive drug target leukocyte elastase, which has been implicated in a number of inflammatory disorders. In order to investigate the structural characteristics of the covalent inhibitor bound to PPE, including hydrogen and hydration of water, a single crystal of PPE for neutron diffraction study was grown in D
O containing 0.2 M sodium sulfate (pD=5.0) using the sitting-drop vapor diffusion method. The crystal was grown to a size of 1.6 mm
by repeated macro-seeding. The neutron diffraction data were collected at room temperature using a BIX-3 diffractometer at the JRR-3 research reactor of the Japan Atomic Energy Agency (JAEA). The data set was integrated and scaled to 2.3 resolution with space group P212121 and cell dimensions of a=51.2, b=57.8 and c=75.6.
Yamamoto, Takumi; Ushigusa, Kenkichi; Sakamoto, Keishi; Imai, Tsuyoshi; Miya, Naoyuki; ; Nagashima, Keisuke; *; Mori, Katsuharu*; Kikuchi, Mitsuru; et al.
JAERI-Research 97-006, 77 Pages, 1997/02
JAERI-Research-97-006.pdf:2.47MB
no abstracts in English
Ikeda, Yoshitaka; Naito, Osamu; Ushigusa, Kenkichi; Sato, Masayasu; Kondoh, Takashi; Ide, Shunsuke; Seki, Masami; Nagashima, Keisuke; S.W.Wolfe*; Asakura, Nobuyuki; et al.
Nuclear Fusion, 34(6), p.871 - 880, 1994/00
Times Cited Count：13 Percentile：46.34(Physics, Fluids & Plasmas)no abstracts in English
Imai, Tsuyoshi; Ushigusa, Kenkichi; Ikeda, Yoshitaka; Naito, Osamu; Yoshida, Hidetoshi; Seki, Masami; Itami, Kiyoshi; Nagashima, Keisuke; Uehara, Kazuya; Nagashima, Takashi
Kaku Yugo Kenkyu, 65(SPECIAL ISSUE), p.99 - 118, 1991/03
no abstracts in English
Tsuji, Shunji; Ushigusa, Kenkichi; Ikeda, Yoshitaka; Imai, Tsuyoshi; Itami, Kiyoshi; Nemoto, Masahiro; Nagashima, Keisuke; Koide, Yoshihiko; Kawano, Yasunori; Fukuda, Takeshi; et al.
Physical Review Letters, 64(9), p.1023 - 1026, 1990/02
Times Cited Count：55 Percentile：88.38(Physics, Multidisciplinary)no abstracts in English
Ushigusa, Kenkichi; Imai, Tsuyoshi; Ikeda, Yoshitaka; Sakamoto, Keishi; F.X.Soeldner*; *; Tsuji, Shunji; Shimizu, Katsuhiro; Naito, Osamu; Uehara, Kazuya; et al.
Nuclear Fusion, 29(2), p.265 - 276, 1989/02
Times Cited Count：17 Percentile：58.82(Physics, Fluids & Plasmas)no abstracts in English
Ushigusa, Kenkichi; Imai, Tsuyoshi; Ikeda, Yoshitaka; Sakamoto, Keishi; F.X.Soldner*; *; Tsuji, Shunji; Shimizu, Katsuhiro; Naito, Osamu; Uehara, Kazuya; et al.
JAERI-M 88-115, 28 Pages, 1988/06
no abstracts in English
Imai, Hisashi*; Shiozaki, Isao*; Yamashita, Ryo*; Kurikami, Hiroshi; Niizato, Tadafumi; Maekawa, Keisuke; Yasue, Kenichi
no journal, ,
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Maekawa, Keisuke; Niizato, Tadafumi; Kurikami, Hiroshi; Asamori, Koichi; Imai, Hisashi*; Shiozaki, Isao*
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Niizato, Tadafumi; Maekawa, Keisuke; Yasue, Kenichi; Asamori, Koichi; Kurikami, Hiroshi; Imai, Hisashi*; Shiozaki, Isao*
no journal, ,
This study presents an application of a combined method based on the Data Flow Diagram (a Geosynthesis methodology developed in previous site-investigation programs, for example the NAGRA Wellenberg project in Switzerland) and the Process Diagrams (or Interaction Matrix; developed in the SKB Safety Report 97) for a sequence of field investigation and analysis activities.
Maekawa, Keisuke; Niizato, Tadafumi; Imai, Hisashi*; Shiozaki, Isao*; Yamashita, Ryo*
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no abstracts in English
Yamashita, Ryo*; Imai, Hisashi*; Shiozaki, Isao*; Maekawa, Keisuke; Niizato, Tadafumi
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no abstracts in English
Tamada, Taro; Kinoshita, Takayoshi*; Ohara, Takashi; Kurihara, Kazuo; Imai, Keisuke*; Kuroki, Ryota; Tada, Toshiji*
no journal, ,
Porcine pancreatic elastase (PPE) is a serine protease classified in the chymotrypsin family. We determined two crystal structures of PPE in complex with peptidic inhibitor FR130180, which mimics the tetrahedral transition intermediate. One is the structure determined using 1.65 resolution neutron diffraction in the combination with 1.20 resolution X-ray diffraction data obtained using the same crystal. The other is the sub-angstrom X-ray structure determined to 0.94 resolution. The structural features obtained from neutron diffraction and X-ray diffraction were compared to understand the detailed scheme of interaction between PPE and its inhibitor. From the observation of hydrogen atom located between the active site His57 and Asp102 by neutron and high resolution X-ray diffraction experiment, it is revealed that the interaction is not a low barrier hydrogen bond, but a short ionic hydrogen bond. Moreover, using neutron diffraction data we show that the hydroxyl group of inhibitor FR13080 bound within the "oxy-anion hole" exhibits an oxy-anion-like tetrahedral intermediate.
Imai, Hisashi*; Shiozaki, Isao*; Yamashita, Ryo*; Maekawa, Keisuke; Niizato, Tadafumi
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Maekawa, Keisuke; Niizato, Tadafumi; Imai, Hisashi*; Shiozaki, Isao*; Yamashita, Ryo*
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