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Tabata, Chihiro; Watanabe, Hirohito*; Shirasaki, Kenji*; Sunaga, Ayaki*; Fukuda, Takamitsu*; Li, D.*; Yamamura, Tomoo*
Journal of Molecular Structure, 1277, p.134870_1 - 134870_8, 2023/04
Times Cited Count:0 Percentile:0.00(Chemistry, Physical)Neutral and cationic U(IV) sandwiched phthalocyanine (Pc) complexes were prepared. The neutral species, UPc, was obtained by the reaction of UCl] and phthalonitrile, and the [UPc][BF] crystals were grown by electrolysis. The structures of the complexes were determined crystallographically. A U(IV) ion has two electrons, which carry a magnetic moment localized at the U sites, making the complex magnetically active. The magnetic susceptibility measurement of UPc revealed that the system was paramagnetic with local magnetic moments down to 2 K, but these magnetic moments were suppressed, possibly by a ligand field effect. The paramagnetism was also confirmed by the magnetization curve without hysteresis. The cationic complex, [UPc][BF]] crystalized in a tetragonal structure with the space group , in which the UPc molecules stacked along the tetragonal -axis. The structure was similar to that of [LnPc][BF]], but with distinct disorder in the stacking plane. The stabilities of the crystal and molecular structures and the electronic configurations of UPc and [UPc][BF]] were evaluated via the calculations that included the multiconfigurational nature of the actinide element.
Ishihara, Kota*; Kobayashi, Masayuki*; Imamura, Kumpei*; Konczykowski, M.*; Sakai, Hironori; Opletal, P.; Tokiwa, Yoshifumi; Haga, Yoshinori; Hashimoto, Kenichiro*; Shibauchi, Takasada*
Physical Review Research (Internet), 5(2), p.L022002_1 - L022002_6, 2023/04
Lower superconducting critical fields of UTe have been determined. Orthorhombic UTe has magnetic easy axis along the -axis. We found perpendicular to showed anomalous enhancement. By comparing with anisotropy of upper critical fields, effect of magnetic fluctuations on superconductivity is suggested.
Xia, C.-J.*; Maruyama, Toshiki; Yasutake, Nobutoshi*; Tatsumi, Toshitaka*; Zhang, Y.-X.*
Physics Letters B, 839, p.137769_1 - 137769_5, 2023/04
Times Cited Count:1 Percentile:59.27(Astronomy & Astrophysics)Otokawa, Yoshinori; Matsuda, Makoto; Abe, Shinichi
JAEA-Technology 2022-037, 23 Pages, 2023/03
Bearing units of rotating shaft system for power generation in the JAEA-Tokai Tandem accelerator had a short operating life from the beginning of the accelerator installation, and even after replacing the bearing unit, early failures often occurred. Therefore, the quantity and frequency of replacement are large, and a lot of time is spent in regular maintenance performed by opening the accelerator pressure vessel, and solving this problem has been a long-standing concern. As a result of considering the cause of this early failure, it was considered that the load caused by parallel, angular, and axial misalignment of the upper and lower bearing units was the cause. In order to solve this problem, we have developed a bearing unit having metal disc-spring couplings in the upper and lower flanges to allow for parallel, angular, and axial misalignment of bearing units. As a result, it is now possible to allow variations in the distance between castings and parallel, angular, and axial misalignment of the upper and lower bearing units. By installing the developed new bearing unit on the rotating shaft system and making improvements while continuing to use it in actual operation, we succeeded in reducing the early failure and extending the operating life by more than double. With this development, the maintenance time has been reduced to one week by reducing the number of replacing the bearing unit. In addition, we have realized one regular maintenance that was carried out about three times a year, and as a benefit, we were able to reduce the amount of sulfur hexafluoride (SF) gas, which is a greenhouse gas, to about 3350% per year. We describe about development of new bearing units and these maintenance status from 2006 to 2020.
Advanced Science Research Center
JAEA-Evaluation 2022-009, 398 Pages, 2023/03
Japan Atomic Energy Agency (hereinafter referred to as "JAEA") consulted an assessment committee, "Evaluation Committee of Research Activities for Advanced Science Research" (hereinafter referred to as "Committee") for final evaluation and prior assessment of "Advanced Science Research", in accordance with "General Guideline for the Evaluation of Government Research and Development (R&D) Activities" by Cabinet Office, Government of Japan, "Guideline for Evaluation of R&D in Ministry of Education, Culture, Sports, Science and Technology" and "Regulation on Conduct for Evaluation of R&D Activities" by JAEA. In response to the JAEA's request, the Committee assessed the research programs and activities of the Advanced Science Research Center (hereinafter referred to as "ASRC") for the period of seven years from April 2015 and the research programs from April 2022. The Committee evaluated the management and the research programs of the ASRC based on the explanatory documents prepared by the ASRC and the oral presentations with questions-and-answers by the Director and the research group leaders. This report summarizes the results of the assessment by the Committee with the Committee report attached.
Kabumoto, Hiroshi; Nakagawa, Sohei; Matsuda, Makoto
JAEA-Conf 2022-002, 146 Pages, 2023/03
"The 34th Meeting for Tandem Accelerators and their Associated Technologies" was held on July 21-22, 2022 organized by Nuclear Science Research Institute of the Japan Atomic Energy Agency. This meeting was held only on-line for preventing the spread of COVID-19 infection. The purpose of this meeting is contribution of development for related technology and of management of facilities through exchange of information among the researchers and engineers using and operating electrostatics accelerator facilities like tandem accelerators. There were 25 presentations which contains current status report of facility, technical development of accelerator, research of application. The total number of participants was a hundred, from 26 universities, research organizations and industries. This meeting consisted of only oral session, a poster session was not carried out because of on-line meeting. This proceeding compiles the contents of report papers in the meeting.
Suzuki, Kazuya; Mizukami, Shigemi*
AIP Advances (Internet), 13(3), p.035225_1 - 035225_6, 2023/03
Times Cited Count:1 Percentile:44.21(Nanoscience & Nanotechnology)We studied MgO barrier magnetic tunnel junctions (MTJs) comprising perpendicularly magnetized MnGa and FeCoB electrodes. In those perpendicular (-) MTJs, we utilized thin metastable bcc CoMn alloys for an interlayer between MnGa and MgO to enhance the tunnel magnetoresistance (TMR). Moreover, we investigated the effect of a thin Mg interlayer between MnGa and CoMn. Owing to the interlayer engineering, we achieved a TMR ratio over 100%, the highest value observed for -MTJs with a tetragonal MnGa electrode. Our study contributes to the further development of spintronic devices using -MTJs with various Mn-based tetragonal alloy electrodes.
Sato, Yuma*; Takeuchi, Yutaro*; Yamane, Yuta*; Yoon, J.-Y.*; Kanai, Shun*; Ieda, Junichi; Ohno, Hideo*; Fukami, Shunsuke*
Applied Physics Letters, 122(12), p.122404_1 - 122404_5, 2023/03
Times Cited Count:2 Percentile:66.71(Physics, Applied)Hattori, Koichi*; Suenaga, Daiki*; Suzuki, Kei; Yasui, Shigehiro*
EPJ Web of Conferences, 276, p.01015_1 - 01015_5, 2023/03
Times Cited Count:0 Percentile:0.91(Physics, Atomic, Molecular & Chemical)We investigate the QCD phase diagram in strong magnetic fields with heavy-quark impurities and determine the ground state within the mean-field analysis. The ground state is characterized by magnitudes of the pairing not only between the light quark and antiquark, i.e., chiral condensate, but also between the light quark and heavy-quark impurity, dubbed the Kondo condensate. We propose signatures of the interplay and/or competition between those two pairing phenomena reflected in the magnitude of the chiral condensate that is saturated with respect to the magnetic-field strength and anomalously increases with increasing temperature.
Maamoun, I.; Tokunaga, Kohei; Dohi, Terumi; Kanno, Futoshi*; Falyouna, O.*; Eljamal, O.*; Tanaka, Kazuya
Frontiers in Nuclear Engineering (Internet), 2, p.1142823_1 - 1142823_17, 2023/03
Recently, the rapid development of nuclear power technologies and the continuous energy demand around the world exhibited massive amounts of contaminated water with radionuclides. Technetium-99 (Tc) is one of the long-lived radionuclides with a highly mobile anionic form (Tc(VII)) in aqueous solutions. Hence, the rapid and efficient Tc(VII) removal from radioactive water has emerged as a challenging issue. In this work, bimetallic nickel/iron nanoparticles (Ni/Fe) were prepared to enhance the immobilization of rhenium (Re(VII)) from aqueous solutions, as the surrogate of Tc(VII).
Opletal, P.; Sakai, Hironori; Haga, Yoshinori; Tokiwa, Yoshifumi; Yamamoto, Etsuji; Kambe, Shinsaku; Tokunaga, Yo
Journal of the Physical Society of Japan, 92(3), p.034704_1 - 034704_5, 2023/03
Times Cited Count:1 Percentile:52.21(Physics, Multidisciplinary)We investigate the physical properties of a single crystal of uranium telluride UTe. We have confirmed that UTe crystallizes in the hexagonal structure with three nonequivalent crystallographic uranium sites. The paramagnetic moments are estimated to be approximately 1 per the uranium site, assuming a uniform moment on all the sites. A ferromagnetic phase transition occurs at = 48 K, where the in-plane magnetization increases sharply, whereas the out of-plane component does not increase significantly. With decreasing temperature further below under field-cooling conditions, the out-of-plane component increases rapidly around T= 26 K. In contrast, the in-plane component hardly changes at T. Specific heat measurement indicates no -type anomaly around T, so this is a cross-over suggesting a reorientation of the ordering moments or successive magnetic ordering on the part of the multiple uranium sites.
Nakata, Koki; Suzuki, Kei
Physical Review Letters, 130(9), p.096702_1 - 096702_6, 2023/03
Times Cited Count:3 Percentile:82.36(Physics, Multidisciplinary)Quantum fluctuations of quantum fields induce a zero-point energy shift under spatial boundary conditions. This quantum phenomenon, called the Casimir effect, has been attracting much attention beyond the hierarchy of energy scales, whereas its application to spintronics has not yet been investigated enough, particularly to ferrimagnetic thin films. Here we fill this gap. Using the lattice field theory, we investigate the Casimir effect induced by quantum fields for magnons and find that the magnonic Casimir effect can arise not only in antiferromagnets but also in ferrimagnets (e.g., YIG). Thus, we pave the way for magnonic Casimir engineering.
Revel, A.*; Wu, J.*; Iwasaki, Hironori*; Ash, J.*; Bazin, D.*; Brown, B. A.*; Chen, J.*; Elder, R.*; Farris, P.*; Gade, A.*; et al.
Physics Letters B, 838, p.137704_1 - 137704_7, 2023/03
Times Cited Count:1 Percentile:59.27(Astronomy & Astrophysics)no abstracts in English
Maamoun, I.; Rushdi, M.*; Falyouna, O.*; Eljamal, R.*; Eljamal, O.*
Separation and Purification Technology, 308, p.122863_1 - 122863_16, 2023/03
Times Cited Count:3 Percentile:30.76(Engineering, Chemical)Kitaori, Aki*; Kanazawa, Naoya*; Kida, Takanori*; Narumi, Yasuo*; Hagiwara, Masayuki*; Kindo, Koichi*; Takeuchi, Tetsuya*; Nakamura, Ai*; Aoki, Dai*; Haga, Yoshinori; et al.
Journal of the Physical Society of Japan, 92(2), p.024702_1 - 024702_6, 2023/02
Times Cited Count:0 Percentile:0.00(Physics, Multidisciplinary)Koura, Hiroyuki
Kaku Deta Nyusu (Internet), (134), p.82 - 96, 2023/02
no abstracts in English
Sato, Tetsuya; Nagame, Yuichiro*
Nihon Butsuri Gakkai-Shi, 78(2), p.64 - 72, 2023/02
The study of the chemistry of superheavy elements, which are located in the heavy extremes of the periodic table, has made considerable progress over the past 20 years, and new approaches based on various ideas have recently been developed. Research groups in Japan have also made significant contributions to the development of research on superheavy elements. Recently, notable results have been reported for the transactinide elements rutherfordium (element 104), dubnium (element 105), and seaborgium (element 106), and the heavy actinides with atomic numbers exceeding 100. The review will focus on the recent main results of these elements. This review outlines the main recent results and touches on future prospects.
Chen, J.*; Yamamoto, Kei; Zhang, J.*; Ma, J.*; Wang, H.*; Sun, Y.*; Chen, M.*; Ma, J.*; Liu, S.*; Gao, P.*; et al.
Physical Review Applied (Internet), 19(2), p.024046_1 - 024046_9, 2023/02
Times Cited Count:6 Percentile:91.88(Physics, Applied)Aikawa, Shu*; Hashimoto, Tadashi; Tanida, Kiyoshi; 73 of others*
Physics Letters B, 837, p.137637_1 - 137637_8, 2023/02
Times Cited Count:2 Percentile:47.44(Astronomy & Astrophysics)Mori, Michiyasu; Maekawa, Sadamichi
Applied Physics Letters, 122(4), p.042202_1 - 042202_5, 2023/01
Times Cited Count:3 Percentile:78.44(Physics, Applied)