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Iyota, Muneyoshi*; Matsuda, Tomoki*; Sano, Tomokazu*; Shigeta, Masaya*; Shobu, Takahisa; Yumoto, Hirokatsu*; Koyama, Takahisa*; Yamazaki, Hiroshi*; Semba, Yasunori*; Ohashi, Haruhiko*; et al.
Journal of Manufacturing Processes, 94, p.424 - 434, 2023/05
Times Cited Count：7 Percentile：75.30(Engineering, Manufacturing)Hashimoto, Shoji*; Tanaka, Taku*; Komatsu, Masabumi*; Gonze, M.-A.*; Sakashita, Wataru*; Kurikami, Hiroshi; Nishina, Kazuya*; Ota, Masakazu; Ohashi, Shinta*; Calmon, P.*; et al.
Journal of Environmental Radioactivity, 238-239, p.106721_1 - 106721_10, 2021/11
Times Cited Count：12 Percentile：56.00(Environmental Sciences)This study was aimed at analysing performance of models for radiocesium migration mainly in evergreen coniferous forest in Fukushima, by inter-comparison between models of several research teams. The exercise included two scenarios of countermeasures against the contamination, namely removal of soil surface litter and forest renewal, and a specific konara oak forest scenario in addition to the evergreen forest scenario. All the models reproduced trend of time evolution of radiocesium inventories and concentrations in each of the components in forest such as leaf and organic soil layer. However, the variations between models enlarged in long-term predictions over 50 years after the fallout, meaning continuous field monitoring and model verification/validation is necessary.
Ohashi, Kunihide*; Hino, Takanori*; Kobayashi, Hiroshi*; Onodera, Naoyuki; Sakamoto, Nobuaki*
Journal of Marine Science and Technology, 24(3), p.884 - 901, 2019/09
Times Cited Count：22 Percentile：78.96(Engineering, Marine)An unsteady Reynolds averaged Navier-Stokes solver with a structured overset grid method has been developed. Velocity pressure coupling is achieved using an artificial compressibility approach, spatial discretization is based on a FVM. Body motions are considered using the grid deformation technique and grid velocities in the convective term. The full multigrid (FMG) method is applied to obtain fast convergence. The cell flag on a coarse grid level is determined using the cell flag on a fine grid level. In the coarse and fine grid level calculations at the FMG stage, the data are interpolated until the finest grid level is achieved at an overset update interval. Then, the data are updated based on the overset relations at the finest grid level and then transferred to a coarser grid level. The computations for flows around a hull form, including an unsteady simulation with regular waves, are demonstrated.
Yoshida, Kensuke*; Fujioka, Shinsuke*; Higashiguchi, Takeshi*; Ugomori, Teruyuki*; Tanaka, Nozomi*; Kawasaki, Masato*; Suzuki, Yuhei*; Suzuki, Chihiro*; Tomita, Kentaro*; Hirose, Ryoichi*; et al.
Applied Physics Letters, 106(12), p.121109_1 - 121109_5, 2015/03
Times Cited Count：14 Percentile：50.49(Physics, Applied)Yoshida, Kensuke*; Fujioka, Shinsuke*; Higashiguchi, Takeshi*; Ugomori, Teruyuki*; Tanaka, Nozomi*; Ohashi, Hayato*; Kawasaki, Masato*; Suzuki, Yuhei*; Suzuki, Chihiro*; Tomita, Kentaro*; et al.
Applied Physics Express, 7(8), p.086202_1 - 086202_4, 2014/08
Times Cited Count：31 Percentile：75.10(Physics, Applied)We demonstrate high conversion efficiency for extreme ultraviolet (EUV) emission at 6.5-6.7 nm from multiple laser beam-produced one-dimensional spherical plasmas. Multiply charged-state ions produce strong resonance emission lines, which combine to yield intense unresolved transition arrays in Gd, Tb, and Mo. The maximum in-band EUV conversion efficiency was observed to be 0.8%, which is one of the highest values ever reported due to the reduction of plasma expansion loss.
Nagasono, Mitsuru*; Harries, J.; Iwayama, Hiroshi*; Togashi, Tadashi*; Tono, Kensuke*; Yabashi, Makina*; Semba, Yasunori*; Ohashi, Haruhiko*; Ishikawa, Tetsuya*; Shigemasa, Eiji*
Physical Review Letters, 107(19), p.193603_1 - 193603_5, 2011/11
Times Cited Count：37 Percentile：81.60(Physics, Multidisciplinary)Hanaki, Hiroshi*; Sanda, Toshio*; Ohashi, Masahisa*
JAEA-Review 2008-047, 266 Pages, 2008/10
JAEA-Review-2008-047.pdf:62.06MB
It is thought to improve the prediction accuracy for burnup characteristics using many burnup data of "Joyo" effectively. It is thought the best way to adjust cross-sections using sensitivity coefficients of burnup characteristics to utilize burnup data of "Joyo". Therefore in this work computer codes for analyzing sensitivity coefficients of burnup characteristics had been prepared since 1992. The results are as follows: (1) The computer codes which could analyze sensitivity coefficients of burnup characteristics taking into consideration plural cycles and refueling were prepared, therefore it came to be able to adjust cross-sections using burnup data and to estimate the accuracy for design of large LMFBR cores. (2) The adequacy of prepared codes was made sure by comparing with direct calculations. (NB: This document is a translation of PNC TJ9124 94-007 Vol.2 published in March 1997.)
Miyazawa, Yutaka*; Sakashita, Tetsuya; Funayama, Tomoo; Hamada, Nobuyuki*; Negishi, Hiroshi*; Kobayashi, Akie*; Kaneyasu, Tomoko*; Oba, Atsushi*; Morohashi, Keita*; Kakizaki, Takehiko*; et al.
Journal of Radiation Research, 49(4), p.373 - 379, 2008/07
Times Cited Count：29 Percentile：64.07(Biology)We examined the role of root cap and elongation zone cells in root hydrotropism using heavy-ion and laser microbeam. Heavy-ion microbeam irradiation of the elongation zone, but not that of the columella cells, significantly and temporary suppressed the development of hydrotropic curvature. However, laser ablation confirmed that columella cells are indispensable for hydrotropism. Systemic heavy-ion broad-beam irradiation suppressed 
expression of 
gene, but not 
gene. Our results indicate that both the root cap and elongation zone have indispensable and functionally distinct roles in root hydrotropism, and that gene expression might be required for hydrotropism in the elongation zone, but not in columella cells.
using heavy-ion microbeamMiyazawa, Yutaka*; Sakashita, Tetsuya; Negishi, Hiroshi*; Kobayashi, Akie*; Kaneyasu, Tomoko*; Oba, Atsushi*; Morohashi, Keita*; Kakizaki, Takehiko*; Funayama, Tomoo; Hamada, Nobuyuki*; et al.
JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 116, 2008/03
We examined the role of root cap and elongation zone cells in root hydrotropism of using heavy ion and laser microbeam. Heavy ion microbeam irradiation of the elongation zone, but not that of the columella cells, significantly and temporarily suppressed the development of hydrotropic curvature. However, laser ablation confirmed that columella cells are indispensable for hydrotropism. Systemic heavy ion broad beam irradiation suppressed de novo expression of INDOLE ACETIC ACID 5 gene. Our results indicate that both the root cap and elongation zone have indispensable and functionally distinct roles in root hydrotropism, and that de novo gene expression might be required for hydrotropism in the elongation zone, but not in columella cells.
Yoshikawa, Hiroshi; Sakaki, Hironao; Sako, Hiroyuki; Takahashi, Hiroki; Shen, G.; Kato, Yuko; Ito, Yuichi; Ikeda, Hiroshi*; Ishiyama, Tatsuya*; Tsuchiya, Hitoshi*; et al.
Proceedings of International Conference on Accelerator and Large Experimental Physics Control Systems (ICALEPCS '07) (CD-ROM), p.62 - 64, 2007/10
J-PARC is a large scale facility of the proton accelerators for the multi-purpose of scientific researches in Japan. This facility consists of three accelerators and three experimental stations. Now, J-PARC is under construction, and LINAC is operated for one year, 3GeV synchrotron has just started the commissioning in this October the 1st. The completion of this facility will be next summer. The control system of accelerators established fundamental performance for the initial commissioning. The most important requirement to the control system of this facility is to minimize the activation of accelerator devices. In this paper, we show that the performances of each layer of this control system have been achieved in the initial stage.
Sn strand subjected to bending strainHirohashi, Masayuki*; Murakami, Haruyuki*; Ishiyama, Atsushi*; Ueda, Hiroshi*; Koizumi, Norikiyo; Okuno, Kiyoshi
IEEE Transactions on Applied Superconductivity, 16(2), p.1721 - 1724, 2006/06
Times Cited Count：9 Percentile：46.28(Engineering, Electrical & Electronic)To demonstrate the applicability of NbSn CICCs to ITER, four NbSn model coils have been constructed and tested. The experimental results showed that the measured critical current (Ic) degraded. In addition, the larger is the applied electromagnetic force, the larger the magnitude of the degradation is. The degradation in n-value was also observed. One of the explanations of this degradation is a local strand bending. This consideration has been supported by the test results. However, general dependence of Ic on periodic bending strain has not been clarified in this test since the experiments were carried out at a certain magnetic field, temperature and strain. Therefore, a numerical simulation code was developed to study the general dependence of the Ic and n-value of the NbSn strand on periodic bending strain. A distributed constant circuit model is applied to simulate current transfer among the filaments in the strand. The simulation results show relatively good agreement with the experiment results but some modification in modeling is required for more accurate simulation.
Maeta, Hiroshi*; Matsumoto, Norimasa*; Haruna, Katsuji*; Saotome, Takao*; Ono, Fumihisa*; Sugai, Hiroyuki; Otsuka, Hideo; Ohashi, Kazutoshi*
Physica B; Condensed Matter, 376-377, p.283 - 287, 2006/04
Times Cited Count：3 Percentile：17.27(Physics, Condensed Matter)Natural and synthetic single crystal diamonds (type Ia, Ib, IIa and IIb) have been characterized by measurements of the X-ray integrated scattering intensity, lattice parameter and diffuse scattering. We found that the lattice parameter is smallest for natural diamond and largest for the B-doped diamond. We measured the diffuse scattering for (400) Bragg reflection for the four types of crystals. The scattering intensity of the natural crystals diffuses asymmetrically to form a streak along the [100] direction parallel to the reciprocal lattice vector. These results suggest the existence of the nitrogen atom platelets on (100) plane in the natural diamond. We also found the diffuse streaks along the [
00] direction for (400) Bragg reflection for the B-doped crystal, suggesting that boron atoms are likely to form precipitates on the (100) plane.
Matsuda, Hideo*; Omura, Ichiro*; Sakiyama, Yoko*; Urano, Satoshi*; Iesaka, Susumu*; Ohashi, Hiromichi*; Hirao, Toshio; Abe, Hiroshi; Ito, Hisayoshi; Mori, Hidenobu; et al.
JAERI-Review 2002-035, TIARA Annual Report 2001, p.11 - 13, 2002/11
no abstracts in English
Ohashi, Hiroshi*; Sato, Seichi*; Kozaki, Tamotsu*
JAERI-Tech 2002-021, 52 Pages, 2002/03
JAERI-Tech-2002-021.pdf:2.95MB
no abstracts in English
Kozai, Naofumi; Adachi, Yoshifusa*; Kawamura, Sachi*; Inada, Koichi*; Kozaki, Tamotsu*; Sato, Seichi*; Ohashi, Hiroshi*; Onuki, Toshihiko; Bamba, Tsunetaka
Journal of Nuclear Science and Technology, 38(12), p.1141 - 1143, 2001/12
This study briefly reports characteristics of Fe-montmorillonite. Fe-montmorillonite was used as a simulant of buffer material in which corrosion products of carbon steel overpack, Fe
, were diffused. We have found that this clay retains Se(VI) for which natural montmorillonite, such as Na+-type and Ca-type, has little retentivity.
Ishihara, Yoshinao*; Matsuoka, Fushiki*; Sagawa, Hiroshi*; Kawahara, Kenichi*; Kataoka, Shinichi*; Shinohara, Yoshinori*; Muroi, Masayuki*; Tsuchiya, Makoto*; Tsujimoto, Keiichi*; Ohashi, Toyo*
JNC TJ8400 2001-011, 259 Pages, 2001/03
JNC-TJ8400-2001-011.pdf:0.99MB
In this study, the basic design study on integrated computer system has been carried out in order to develop the integrated methodologies for future research and development activities of geological disposal system. The key conclusions are summarized as follows: (1) As the result of the investigation of work items and associated flow of information (data) between items in the second progress report by JNC, the interaction matrix and work flow chart have been identified in order to specify the basic configuration of the integrated computer system. In addition, the model chain and the structure of data relation between the repository design study and safety assessment study have been summarized. (2)We organized and examined the system factor and the information process flow in the design, safety analysis, and geological environment study based on the 2000 Report by JNC. Then we analyzed the workflow of geological disposal business when a specific site for a repository is fixed to obtain the system factor and the information process flow. We consider the fracture/porous media, site location (land/under the sea), and long-term stability of the crust (upheaval/sink) as the key factors in examining the workflow of geological disposal business. Then we organized the information change between the design and other study in geological disposal based on the 2000 Report by JNC. We examined the ideal workflow in which the design, safety analysis, and geologic environment study of geological disposal are closely coupled. We examined the scientific and technical base of the knowledge base (the system factor and the information process flow) which is derived from the above to construct the hierarchical structure of the knowledge base for geological disposal. (3)As the result of the interaction matrix and work flow chart for the R&D activities, the conceptual design and the function diagram on the integrated computer system has been proposed. (4)We examined the plan to ...
Kozai, Naofumi; Inada, Koichi*; Kozaki, Tamotsu*; Sato, Seichi*; Ohashi, Hiroshi*; Bamba, Tsunetaka
Journal of Contaminant Hydrology, 47(2-4), p.149 - 158, 2001/02
Times Cited Count：15 Percentile：41.31(Environmental Sciences)no abstracts in English
Takano, Masahide; Minato, Kazuo; Fukuda, Kosaku; Sato, Seichi*; Ohashi, Hiroshi*
Journal of Nuclear Science and Technology, 35(7), p.485 - 493, 1998/07
Times Cited Count：4 Percentile：38.51(Nuclear Science & Technology)no abstracts in English
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Takano, Masahide; Minato, Kazuo; Fukuda, Kosaku; Sato, Seichi*; Ohashi, Hiroshi*
Journal of Alloys and Compounds, 278, p.277 - 282, 1998/00
Times Cited Count：1 Percentile：19.43(Chemistry, Physical)no abstracts in English
Takano, Masahide; Minato, Kazuo; Fukuda, Kosaku; Sato, Seichi*; Ohashi, Hiroshi*
JAERI-Research 97-021, 19 Pages, 1997/03
JAERI-Research-97-021.pdf:0.74MB
no abstracts in English
