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Nakanishi, Takumi*; Hori, Yuta*; Shigeta, Yasuteru*; Sato, Hiroyasu*; Kiyanagi, Ryoji; Munakata, Koji*; Ohara, Takashi; Okazawa, Atsushi*; Shimada, Rintaro*; Sakamoto, Akira*; et al.
Journal of the American Chemical Society, 145(35), p.19177 - 19181, 2023/08
Times Cited Count：1 Percentile：39.98(Chemistry, Multidisciplinary)Nakanishi, Takumi*; Hori, Yuta*; Shigeta, Yasuteru*; Sato, Hiroyasu*; Wu, S.-Q.*; Kiyanagi, Ryoji; Munakata, Koji*; Ohara, Takashi; Sato, Osamu*
Physical Chemistry Chemical Physics, 25(17), p.12394 - 12400, 2023/05
Times Cited Count：1 Percentile：44.88(Chemistry, Physical)Kinoshita, Norikazu*; Nagaoka, Mika; Nakanishi, Takashi*
Science of the Total Environment, 753, p.142087_1 - 142087_10, 2021/01
Times Cited Count：4 Percentile：32.67(Environmental Sciences)The distribution of the anthropogenic radionuclide americium-241 (
Am), a decay product of Pu discharged from atmospheric tests of nuclear weapons, was investigated to resolve its horizontal and vertical migration in the Tropical East Pacific. We analyzed Am concentrations in seawater samples collected in 2003. On comparing the Am concentrations with the previously determined concentrations of 
Pu in the same samples, the vertical profiles of Am were found to be similar to those of Pu. At some stations, the maximum concentration of Am occurred 100-200 m deeper than that of Pu. The Am/Pu ratios in the North Pacific and South Pacific were comparable to one another, and were typical of the ratio for the Pacific. The Am distribution was influenced by the water mass at depths below 400 m. The Am data support the view there is a current flowing at depths of 400-3000 m from the North Pacific through the equator to the South Pacific. In addition, the Am vertical profile was explained by using a box model that considers the decay of Pu and adsorption and scavenging by suspended particles. The different depths for the maximum concentrations of Am and Pu observed at some stations were well explained by the model and by the distribution of CaCO
particles. The residence time of Am in the Pacific was also estimated by using the model.
Numata, Naoto*; Asakawa, Tomoyuki*; Sakai, Hiroshi*; Umemori, Kensei*; Furuya, Takaaki*; Shinoe, Kenji*; Enami, Kazuhiro*; Egi, Masato*; Sakanaka, Shogo*; Michizono, Shinichiro*; et al.
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.566 - 570, 2015/09
no abstracts in English
Yin, Y.-G.; Suzui, Nobuo; Kawachi, Naoki; Yamaguchi, Mitsutaka; Tanoi, Keitaro*; Ishii, Satomi; Nakanishi, Tomoko*; Chino, Mitsuo*; Nakamura, Shinichi*; Watabe, Hiroshi*; et al.
Hoshasen To Sangyo, (133), p.45 - 48, 2012/12
no abstracts in English
Yin, Y.-G.; Suzui, Nobuo; Yamaguchi, Mitsutaka; Kawachi, Naoki; Tanoi, Keitaro*; Nakanishi, Tomoko*; Chino, Mitsuo*; Nakamura, Shinichi*; Fujimaki, Shu
Nihon Dojo Hiryo Gaku Zasshi, 83(3), p.296 - 300, 2012/06
no abstracts in English
Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05
Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.
Furuya, Takaaki*; Hara, Kazufumi*; Hosoyama, Kenji*; Kojima, Yuji*; Nakai, Hirotaka*; Nakanishi, Kota*; Sakai, Hiroshi*; Umemori, Kensei*; Sawamura, Masaru; Shinoe, Kenji*
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2923 - 2925, 2010/05
A prototype module including a couple of 1.3 GHz superconducting 9-cell cavities has been designed as the main linac of cERL which is the test facility to establish the basic ERL technology at KEK. The shape of 9-cell Nb structure is optimized to accelerate a CW beam of 100 mA with sufficiently damped higher order modes (HOM) which is achieved by adopting an eccentric fluted beam pipe and a cylindrical beam pipe of a large diameter of 120 mm. Extracted HOMs are absorbed by the ferrite cylinders bonded on the copper beam pipes by HIP process. A power coupler with double disk-ceramics has been developed to transfer an RF of 20 kW CW to the cavity in full reflection. The test results of fabrication, cooling and RF performance for these components are integrated as the prototype module of the main linac for cERL facility.
Yoshida, Yasushi*; Nakazawa, Toshiyuki*; Yoshikawa, Hideki; Nakanishi, Takashi*
Journal of Radioanalytical and Nuclear Chemistry, 280(3), p.541 - 545, 2009/06
Times Cited Count：12 Percentile：62.14(Chemistry, Analytical)Coprecipitation experiment of Ra in gypsum was done with oversaturation method. Derived partition coefficient is,0.71
0.53. Partition coefficient of Ra in gypsum was not reported. Comparing with that of Ra in barite and of Sr in gypsum, a value of partition coefficient in the present study is though to be reasonable.
Hasegawa, Makoto; Nakanishi, Takashi*; Fujii, Yasuhiko*; Odaka, Tomohiro*
Hosha Kagaku Nyusu, (17), p.29 - 35, 2008/03
no abstracts in English
Yoshida, Yasushi*; Yoshikawa, Hideki; Nakanishi, Takashi*
Geochemical Journal, 42(3), p.295 - 304, 2008/00
Times Cited Count：15 Percentile：37.55(Geochemistry & Geophysics)Partition coefficients (
) of Ra and Ba in calcite were derived in an experiment of coprecipitation. Free Drift Method (FDM) was adopted. As a result of experiment, of Ra and Ba were 9.4e-3 and 4.7e-3, respectively. A saturation state is expected to be a low oversaturation in duration of experiment and according to an estimated saturation index, a composition of a final solution was close to equilibrium with calcite. The values of 
and 
showed the similar extent. It implies that difference of size of ionic radius does not affect incorporation behavior of Ra and Ba in calcite.
Kofuji, Hirohide; Sato, Fuminori; Myochin, Munetaka; Nakanishi, Shigeyuki*; Kormilitsyn, M. V.*; Ishunin, V.*; Bychkov, A. V.*
Journal of Nuclear Science and Technology, 44(3), p.349 - 353, 2007/03
Times Cited Count：8 Percentile：51.08(Nuclear Science & Technology)The Oxide Electrowinning method has being studied as one of the candidate dry reprocessing concepts of future fuel cycle system. On the MOX co-deposition process, main process of that method, some fundamental experiments have been performed to confirm its feasibility. In the experiments, several parameters were set to study the suitable electrolysis condition to obtain desired granule of MOX. The concentrations of uranium, plutonium, FP simulators, and CP simulators were adopted as the parameters. The blowing gas composition during the electrolysis was also set as the variable condition. Through these experiments, it was clarified that the partial pressure of chlorine gas during electrolysis was important to obtain MOX granule with high Pu concentration without generating bottom precipitation in melt. Finally, adequacy of process control method for MOX co-electrolysis was confirmed through the test using spent FR fuel.
Sato, Fuminori; Mizuguchi, Koji; Nakanishi, Shigeyuki; Myochin, Munetaka
Nihon Genshiryoku Gakkai Wabun Rombunshi, 5(4), p.268 - 281, 2006/12
MOX co-deposition process, which is one of the main parts of oxide electrowinning process, was studied by both sides of examination and analysis. Parameter tests using U and Pu were performed as basic examination, and fundamental data of the process such as polarization property of molten salt including U and Pu, current efficiency of electrolysis and PuO
concentration in recovered deposit, etc. were acquired. In addition, to analyze the process behavior, especially polarization property at electrolysis, a reaction model considering Pu
, Pu
, UO
, UO
, PuO and PuOin molten NaCl-2CsCl salt was developed. The validity of this model was confirmed by comparison of the experimental and analytical results. Using this model behavior of chemical species in the process was studied and control factors of MOX co-deposition process were discussed.
Re populated by the 
reaction from laser Compton scattering 
rays at the electron storage ring NewSUBARUHayakawa, Takehito; Miyamoto, Shuji*; Hayashi, Yukio; Kawase, Keigo*; Horikawa, Ken*; Chiba, Satoshi; Nakanishi, Kosuke*; Hashimoto, Hisanobu*; Ota, Takeshi*; Kando, Masaki; et al.
Physical Review C, 74(6), p.065802_1 - 065802_5, 2006/12
Times Cited Count：29 Percentile：82.68(Physics, Nuclear)We report a half-life of the ground state of Re populated by the 
ReRe reaction with the laser Compton scattering -rays generated through relativistic engineering. The -rays are provided at the electron storage ring NewSUBARU. The previous experiment using deuteron-induced reactions has yielded a recommended half-life of the 3
ground state of Re to be 38.0 0.5 d, including a possible contribution from the 8 isomer (
= 169 8 d) of Re since the presence of the isomer was not known at that time. In contrast, the reaction has an advantage to selectively populate the ground state because this reaction does not bring large angular momentum. The measured half-life of 35.4 0.7 d is shorter than the previous half-life by about 7%. This difference is crucial for applications using the activation method.
Pb(
He,
) reaction at 410 MeVZegers, R. G. T.*; Abend, H.*; Akimune, Hidetoshi*; Van den Berg, A. M.*; Fujimura, Hisako*; Fujita, Hirohiko*; Fujita, Yoshitaka*; Fujiwara, Mamoru; Gal
s, S.*; Hara, Keigo*; et al.
Nuclear Physics A, 731, p.121 - 128, 2004/02
Times Cited Count：11 Percentile：56.77(Physics, Nuclear)no abstracts in English
CuHara, Keigo*; Adachi, Takeshi*; Akimune, Hidetoshi*; Daito, Izuru*; Fujimura, Hisako*; Fujita, Yoshitaka*; Fujiwara, Mamoru; Fushimi, Kenichi*; Hara, Kaoru*; Harakeh, M. N.*; et al.
Physical Review C, 68(6), p.064612_1 - 064612_9, 2003/12
Times Cited Count：11 Percentile：57.99(Physics, Nuclear)no abstracts in English
Pb(He,) reaction at 410 MeVZegers, R. G. T.; Abend, H.*; Akimune, Hidetoshi*; Van den Berg, A. M.*; Fujimura, Hisako*; Fujita, Hirohiko*; Fujita, Yoshitaka*; Fujiwara, Mamoru; Gals, S.*; Hara, Keigo*; et al.
Physical Review Letters, 90(20), p.202501_1 - 202501_4, 2003/05
Times Cited Count：49 Percentile：84.91(Physics, Multidisciplinary)no abstracts in English
Ito, Takahiko*; Nakanishi, Shigemitsu*; Umezawa, Kenji*; Yamamoto, Shunya; Narumi, Kazumasa; Naramoto, Hiroshi
JAERI-Review 99-025, TIARA Annual Report 1998, p.182 - 184, 1999/10
no abstracts in English
;
Denki Gakkai-Shi, 118(2), p.108 - 111, 1998/00
no abstracts in English
; ; ; ;
Denki Gakkai Rombunshi, D, 117-D(5), p.579 - 588, 1997/05
no abstracts in English
