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Hirahara, Toru*; Otrokov, M. M.*; Sasaki, Taisuke*; Sumida, Kazuki*; Tomohiro, Yuta*; Kusaka, Shotaro*; Okuyama, Yuma*; Ichinokura, Satoru*; Kobayashi, Masaki*; Takeda, Yukiharu; et al.
Nature Communications (Internet), 11, p.4821_1 - 4821_8, 2020/09
Times Cited Count：42 Percentile：93.06(Multidisciplinary Sciences)Asano, Shiro*; Okuyama, Toshihisa*; Onawa, Toshio*; Yanagi, Yutaka*; Ejiri, Mitsuru*; Kanahara, Toshio*; Ichihashi, Koji*; Kikuchi, Atsushi*; Mizumaki, Shoichi*; Masaki, Kei; et al.
Fusion Engineering and Design, 86(9-11), p.1816 - 1820, 2011/10
Times Cited Count：12 Percentile：66.68(Nuclear Science & Technology)The real vacuum vessel (VV) manufacturing of JT-60SA has started since Nov. 2009 at Toshiba. Prior to starting manufacturing, fundamental welding R&Ds had been performed by three stages. In the first stage, primary tests for screening welding method were performed. In the second stage, the trial welding for 1m-long straight and curved double shell samples were conducted. The dependences of welding quality and distortion on the welding conditions, such as arc voltage and current, setting accuracy, welding sequence, the shape of grooves, etc. were measured. In addition, welding condition with low heat input was explored. In the last stage, fabrication sequence was confirmed and established by the trial manufacturing of the 20
upper half mock-up. This poster presents the R&D results obtained in the first and second stages.
up to 30TInami, Toshiya; Owada, Kenji; Matsuda, Yasuhiro*; Ouyang, Z. W.*; Nojiri, Hiroyuki*; Matsumura, Takeshi*; Okuyama, Daisuke*; Murakami, Yoichi*
Journal of Physics; Conference Series, 211, p.012010_1 - 012010_6, 2010/02
Times Cited Count：3 Percentile：75.75(Physics, Applied)Inami, Toshiya; Owada, Kenji; Matsuda, Yasuhiro*; Ouyang, Z. W.*; Nojiri, Hiroyuki*; Matsumura, Takeshi*; Okuyama, Daisuke*; Murakami, Yoichi*
Journal of the Physical Society of Japan, 78(3), p.033707_1 - 033707_4, 2009/03
Times Cited Count：16 Percentile：65.71(Physics, Multidisciplinary)
1)-OTakahashi, Shin*; Fujimoto, Yosuke*; Teraoka, Yuden; Yoshigoe, Akitaka; Okuyama, Hiroshi*; Aruga, Tetsuya*
Surface Science, 601(18), p.3809 - 3812, 2007/09
Times Cited Count：4 Percentile：22.63(Chemistry, Physical)Supersonic molecular beam techniques with 0.5-1.0eV and high resolution X-ray photoelectron spectroscopy using synchrotron radiation were applied to the dynamics study for oxygen dissociative adsorption on Ru(0001). Increase of adsorption probability and saturation coverage with increasing translational energy suggests a direct dissociation mechanism. We measured uptake curves with and without heating a molecular beam source to verify internal energy effects. We found drastic enhancement of dissociative adsorption. In comparison with rotational and translational cooling during beam expansion, vibrational populations are known to be almost unrelaxed. Then, we concluded that adsorption enhancement was mainly caused by vibrational excitation, indicating that dissociation barrier was located in the exit channel on the potential energy surface. Such vibrational effect was also found on oxygen pre-covered Ru(0001) surface with a 0.5 monolayer corresponding to a p(21) structure.
Torii, Tatsuo; Okuyama, Shinichi; Ishizuka, Akihiro
Tokyo Daigaku Uchusen Kenkyujo Heisei-17-Nendo Kyodo Riyo Kenkyu, Kenkyu Seika Hokokushu, P. 129, 2006/00
no abstracts in English
Kanai, Yutaka*; Okuyama, Yasuko*; Seo, Toshihiro; Sakamaki, Yukio*
Geochemical Journal, 32(6), p.351 - 366, 1998/12
Times Cited Count：10 Percentile：25.92(Geochemistry & Geophysics)None
Torii, Tatsuo; Okuyama, Shinichi; Ishizuka, Akihiro; Nozaki, Tatsuo; Nawa, Yasunori*; Sugita, Takeshi*
no journal, ,
ray dose-rate increases associated with winter thunderstorm activities have been observed at the coastal area of the Sea of Japan. The features are clarified from the measured data obtained by environmental radiation monitors. In order to investigate the generation of energetic radiation which originates in thunderstorm electric fields, we have calculated the behavior of secondary cosmic rays (electromagnetic component; muon) in electric fields with Monte Carlo method. In the calculation, the electron and photon fluxes have increased greatly in the region where the field strength exceeds about 280 P(z) kV/m-atm, where P(z) is the atmospheric pressure (atm) at altitude z (m),.and these energy spectra show a large increase in the energy region up to a few tens of MeV. We have also carried out the Monte Carlo calculations of the beta and rays emitted by radon progenies in thunderstorm electric fields. By the calculation for the radon progeny, the electron flux shows notable increases in the strong electric field region, while the photon flux does not fluctuate significantly. As well as the secondary cosmic rays, the radon progeny products form a large part of the energetic charged particles in the atmosphere. Therefore, they can serve as the source of a considerable amount of runaway electrons, through their ionization process with air molecules. These results indicate that the production of energetic electrons plays an important role in the intensive ionization of the air, and as a result a significant growth of electric conductivity in thunderstorm electric fields. These productions may also induce the lightning discharge by these processes.
under strong pulsed magnetic fieldsInami, Toshiya; Owada, Kenji; Matsuda, Yasuhiro*; Nojiri, Hiroyuki*; Okuyama, Daisuke*; Matsumura, Takeshi*; Murakami, Yoichi*
no journal, ,
no abstracts in English
Inami, Toshiya; Owada, Kenji; Ouyang, Z. W.*; Matsuda, Yasuhiro*; Nojiri, Hiroyuki*; Matsumura, Takeshi*; Okuyama, Daisuke*; Murakami, Yoichi*
no journal, ,
no abstracts in English
Inami, Toshiya; Owada, Kenji; Matsuda, Yasuhiro*; Ouyang, Z. W.*; Nojiri, Hiroyuki*; Matsumura, Takeshi*; Okuyama, Daisuke*; Murakami, Yoichi*
no journal, ,
Asano, Shiro*; Ejiri, Mitsuru*; Yanagi, Yutaka*; Ichihashi, Koji*; Kikuchi, Atsushi*; Mizumaki, Shoichi*; Okuyama, Toshihisa*; Masaki, Kei; Shibama, Yusuke; Katayama, Masahiro*; et al.
no journal, ,
no abstracts in English
Kumasaka, Hiroo*; Kobayashi, Shinji*; Kosuga, Keiichi*; Okuyama, Yasuji*; Kusano, Takashi*; Kurita, Kazuaki*; Yamawaki, Hiroyuki; Sato, Toshinori
no journal, ,
Shotcreting is currently underway in the south research access tunnel 500 m underground at Mizunami Underground Research Laboratory. The use of the low alkaline super shotcrete spraying method, which makes it possible to obtain high strength and high stiffness quickly after spraying while minimizing an environmental impact, is being considered as a means of stabilizing an excavated rock surface whose condition is rapidly deteriorating. For the purpose of evaluating the applicability of the method to the shotcreting work currently in progress, a verification field test was conducted. This paper briefly reports on the test.
Nakaya, Atsushi*; Tada, Hiroyuki*; Okuyama, Yasuji*; Iwasaki, Masahiro*; Kusano, Takashi*; Kubo, Yohei*; Yamawaki, Hiroyuki; Sato, Toshinori
no journal, ,
no abstracts in English
Na and 
Be depositions in Tsuruga cityYoshida, Keisuke; Kato, Shingo; Inoue, Mutsuo*; Ishizuka, Akihiro; Okuyama, Shinichi
no journal, ,
Na is observed for environmental monitoring of Monju fast breeder reactor because Monju reactor contains Na in primary coolant. But Na is produced in upper atmosphere, therefore, Na is detected in assembled deposition sample. To increase accuracy of environmental monitoring, it is necessary to understand transport and supply process of Na and Be depositions from high latitude region where a lot of Na is produced. We collect deposition samples at Tsuruga city to measure Na and collect Be deposition data in 5 sites in Fukui prefecture and Ishikawa prefecture. Because Na and Be shows good correlation, Na have same behavior with Be. Be deposition is maximum at Kanazawa city and minimum at Shika town, but Be deposition is maximum in Winter season at all sites. Be deposition and precipitation shows correlation. From the above, Winter monsoon transport Be and Na from high latitude region and precipitation provide these nuclides to ground surface at Tsuruga city. The deference of Be deposition in Winter season is likely owing to height of mountain and distance of sampling sites.
Kato, Shingo; Ishizuka, Akihiro; Okuyama, Shinichi; Nozaki, Tatsuo; Hayashi, Gaku*; Yasuda, Nakahiro*; Torii, Tatsuo*; Ando, Takasuke*
no journal, ,
no abstracts in English
Hayashi, Gaku*; Torii, Tatsuo*; Ishizuka, Akihiro; Okuyama, Shinichi; Kato, Shingo; Nozaki, Tatsuo; Yasuda, Nakahiro*
no journal, ,
no abstracts in English
