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Mikami, Nao*; Ueki, Yoshitaka*; Shibahara, Masahiko*; Aizawa, Kosuke; Ara, Kuniaki*
International Journal of Multiphase Flow, 171, p.104688_1 - 104688_13, 2024/01
Times Cited Count：0 Percentile：0(Mechanics)Mikami, Nao*; Ueki, Yoshitaka*; Shibahara, Masahiko*; Aizawa, Kosuke; Ara, Kuniaki
Proceedings of 17th International Heat Transfer Conference (IHTC-17) (Internet), 9 Pages, 2023/08
Mikami, Nao*; Ueki, Yoshitaka*; Shibahara, Masahiko*; Aizawa, Kosuke; Ara, Kuniaki
Journal of Sound and Vibration, 561, p.117797_1 - 117797_14, 2023/05
Times Cited Count：1 Percentile：59.1(Acoustics)Ueki, Yoshitaka*; Hashimoto, Shunsaku*; Shibahara, Masahiko*; Aizawa, Kosuke; Ara, Kuniaki
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 5 Pages, 2023/05
Mikami, Nao*; Ueki, Yoshitaka*; Shibahara, Masahiko*; Aizawa, Kosuke; Ara, Kuniaki
International Journal of Multiphase Flow, 159, p.104340_1 - 104340_8, 2023/02
Times Cited Count：5 Percentile：54.22(Mechanics)This study covers the accidental generation of bubble jet flow caused by steam generator (SG) tubes damaging in sodium cooled fast reactors (SFRs). The main objective of this study is to develop a novel state sensing method of bubble jet flow based on acoustic recognition and deep learning. Prior to the application of this method to actual SFRs, we utilize air and water as simulant fluids in order to perform the proof of concept. This study is divided into three phases. The first phase is the acquisition and analysis of pipe flow sound and bubble jet flow sound, each of which simulates the normal and anomaly sound from SG tubes in SFRs. The second phase is the preprocessing of acoustic signals and feature extraction. The third phase is the building of deep learning models and performance evaluation. As a result, every of our proposed models could distinguish between pipe flow sound and bubble jet sound with an accuracy of almost 100.00%, and the best model could classify pipe flow sound and three types of bubble jet flow sound with an accuracy of 99.76%. This result suggests that the acoustic recognition with deep learning has great potential to sense the state of bubble jet flow in actual SFRs.
113 of the 113th elementMorita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Kudo, Yuki*; Sumita, Takayuki*; Wakabayashi, Yasuo*; Yoneda, Akira*; Tanaka, Kengo*; et al.
Journal of the Physical Society of Japan, 81(10), p.103201_1 - 103201_4, 2012/10
Times Cited Count：167 Percentile：97.31(Physics, Multidisciplinary)An isotope of the 113th element, 113, was produced in a nuclear reaction with a 
Zn beam on a 
Bi target. We observed six consecutive 
decays following the implantation of a heavy particle in nearly the same position in the semiconductor detector, in extremely low background condition. The fifth and sixth decays are fully consistent with the sequential decays of 
Db and 
Lr both in decay energies and decay times. This indicates that the present decay chain consisted of 113, 
Rg (Z = 111), 
Mt (Z = 109), 
Bh (Z = 107), Db (Z = 105), and Lr (Z = 103) with firm connections. This result, together with previously reported results from 2004 and 2007, conclusively leads the unambiguous production and identification of the isotope 113, of the 113th element.
SO
/HNO
mixed solutionLi, Z.*; Toyoshima, Atsushi; Asai, Masato; Tsukada, Kazuaki; Sato, Tetsuya; Sato, Nozomi; Kikuchi, Takahiro; Nagame, Yuichiro; Sch
del, M.; Pershina, V.*; et al.
Radiochimica Acta, 100(3), p.157 - 164, 2012/03
Times Cited Count：14 Percentile：68.93(Chemistry, Inorganic & Nuclear)Toyoshima, Atsushi; Kasamatsu, Yoshitaka*; Tsukada, Kazuaki; Asai, Masato; Ishii, Yasuo; Tome, Hayato*; Nishinaka, Ichiro; Sato, Tetsuya; Nagame, Yuichiro; Schdel, M.; et al.
Journal of Nuclear and Radiochemical Sciences, 11(1), p.7 - 11, 2010/06
The extraction behavior of rutherfordium (Rf) into trioctylphosphine oxide (TOPO) from 2.0 - 7.0 M HCl solution was studied together with that of the homologues Zr and Hf. The extracted yields of Rf, Zr, and Hf increased with an increase of HCl concentration, and the sequence of their extraction was Zr 
Hf 
Rf. It is suggested that the stability of the RfCl
2(TOPO) complex is lower than that of the corresponding species of the homologues.
Tsukada, Kazuaki; Haba, Hiromitsu*; Asai, Masato; Toyoshima, Atsushi; Akiyama, Kazuhiko*; Kasamatsu, Yoshitaka; Nishinaka, Ichiro; Ichikawa, Shinichi; Yasuda, Kenichiro; Miyamoto, Yutaka; et al.
Radiochimica Acta, 97(2), p.83 - 89, 2009/02
Times Cited Count：21 Percentile：77.63(Chemistry, Inorganic & Nuclear)Anion-exchange chromatography of element 105, dubnium (Db), produced in the 
Cm(
F, 5n)Db reaction is investigated together with the homologues Nb and Ta, and the pseudo-homologue Pa in 13.9 M hydrofluoric acid (HF) solution. The distribution coefficient (K
) of Db on an anion-exchange resin is successfully determined by running cycles of the 1702 chromatographic column separations. The result clearly indicates that the adsorption of Db on the resin is significantly different from that of the homologues and that the adsorption of anionic fluoro complexes of these elements decreases in the sequence of Ta 
Nb Db Pa.
Sakurai, Kiyoshi; Ueki, Kotaro*; Naito, Yoshitaka*
Nihon Genshiryoku Gakkai-Shi, 43(3), p.219 - 220, 2001/03
no abstracts in English
Sakurai, Kiyoshi; Kume, Etsuo; Yatabe, Shigeru*; Maekawa, Fujio; Yamamoto, Toshihiro; Nagaya, Yasunobu; Mori, Takamasa; Ueki, Kotaro*; Naito, Yoshitaka*
JAERI-Review 2000-034, 133 Pages, 2001/02
JAERI-Review-2000-034.pdf:7.69MB
no abstracts in English
Sakurai, Kiyoshi; Kume, Etsuo; Yatabe, Shigeru*; Maekawa, Fujio; Yamamoto, Toshihiro; Nagaya, Yasunobu; Mori, Takamasa; Ueki, Kotaro*; Naito, Yoshitaka*
Nihon Genshiryoku Gakkai-Shi, 42(10), p.1062 - 1065, 2000/10
no abstracts in English
Sakurai, Kiyoshi; Ueki, Kotaro*; Naito, Yoshitaka*
Nihon Genshiryoku Gakkai-Shi, 42(10), p.1048 - 1049, 2000/10
no abstracts in English
Sakurai, Kiyoshi; Yamamoto, Toshihiro; Ueki, Kotaro*; Mori, Takamasa; Nomura, Yasushi; Naito, Yoshitaka*
Journal of Nuclear Science and Technology, 37(Suppl.1), p.446 - 448, 2000/03
no abstracts in English
Sakurai, Kiyoshi; Ueki, Kotaro*; Naito, Yoshitaka*
Nihon Genshiryoku Gakkai-Shi, 42(2), p.114 - 115, 2000/02
no abstracts in English
Toyoshima, Atsushi; Kasamatsu, Yoshitaka; Tsukada, Kazuaki; Haba, Hiromitsu*; Asai, Masato; Ishii, Yasuo; Tome, Hayato; Sato, Tetsuya; Nishinaka, Ichiro; Nagame, Yuichiro; et al.
no journal, ,
no abstracts in English
spectroscopy of N = 155 and 157 nuclei using a gas-jet transport techniqueAsai, Masato; Tsukada, Kazuaki; Sakama, Minoru*; Ishii, Yasuo; Toyoshima, Atsushi; Ishii, Tetsuro; Nishinaka, Ichiro; Nagame, Yuichiro; Kasamatsu, Yoshitaka; Haba, Hiromitsu*; et al.
no journal, ,
Alpha- spectroscopy of 
No and 
Rf nuclei with the neutron number N=155 and 157 have been performed for the first time at the JAEA tandem accelerator using a gas-jet transport technique. Spin-parities and neutron single-particle configurations of ground states of these nuclei as well as excited states in their daughter nuclei have been identified. On the basis of these experimental results, energy spacings and order of neutron single-particle orbitals between N=153 and 161 were evaluated. The result implies that the order of the neutron orbitals between N=153 and 161 should be inverted between lighter nuclei around 
Fm and heavier ones around 
Hs.
Nagame, Yuichiro; Toyoshima, Atsushi; Ishii, Yasuo; Tsukada, Kazuaki; Asai, Masato; Tome, Hayato; Kasamatsu, Yoshitaka; Nishinaka, Ichiro; Sato, Tetsuya; Haba, Hiromitsu*; et al.
no journal, ,
We present a study of fluoride complex formation of Rf at Japan Atomic Energy Agency (JAEA). Anion- and cation-exchange behavior of Rf was systematically investigated in HF/HNO mixed solution together with the lighter homologues Zr and Hf using the automated ion-exchange separation apparatus coupled with the detection system for alpha spectroscopy. We unequivocally determined the species of Rf on the binding sites of the resin as the hexafluoro complex [RfF
]
. It is found that there is about two-orders of magnitude difference in the fluoride ion concentration between Rf and the homologues for the formation of the hexafluoro complexes. The result clearly demonstrates that the formation of the fluoride complexes of Rf is much weaker than those of the homologues Zr and Hf.
-ray spectroscopy of the heaviest nuclei at JAEA tandem acceleratorAsai, Masato; Tsukada, Kazuaki; Sakama, Minoru*; Ishii, Yasuo; Toyoshima, Atsushi; Ishii, Tetsuro; Nishinaka, Ichiro; Nagame, Yuichiro; Kasamatsu, Yoshitaka; Haba, Hiromitsu*; et al.
no journal, ,
Recent results on the -ray spectroscopic studies of the heaviest nuclei at the JAEA tandem accelerator are reviewed. The nuclei 
No, 
No, and Rf studied in the present work are the heaviest and the most neutron-rich nuclei that -ray spectroscopic studies have ever been performed for. Excited-state energies, spin-parities, and single-particle configurations of those nuclei and their daughters have been established by means of - coincidence spectroscopy. The deduced energy spacings and order of neutron single-particle orbitals suggest that the higher-order deformations play an important role in level structure of the superheavy nuclei in this region.
mixed solution using an on-line chemical apparatusTsukada, Kazuaki; Kasamatsu, Yoshitaka*; Asai, Masato; Toyoshima, Atsushi; Ishii, Yasuo; Li, Z.; Kikuchi, Takahiro; Sato, Tetsuya; Nagame, Yuichiro; Schdel, M.; et al.
no journal, ,
We have investigated the chemical behavior of Db together with its group-5 homologues by anion-exchange chromatography in HF/HNO mixed solution using a rapid online chemical apparatus (AIDA-II). The nuclides Db, 
Nb and 
Ta were produced in the Cm(F, 
n), 
Ge(F, 
n) and Gd(F, n) reactions, respectively, at the JAEA tandem accelerator. On-line anion-exchange separations of Db, Nb and Ta were performed using the AIDA-II. Thousand times of anion-exchange separations were conducted using AIDA-II. events were registered, and the 
values for Db was evaluated. From these results, the adsorption sequence Pa 
Db Nb 
Ta was determined. The present result shows a notable difference in the adsorption behavior between Db and its homologue Ta. In the conference, the present status and the perspective of the aqueous chemistry of Db at JAEA will be also presented.
