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SnSe
Ren, Q.*; Gupta, M. K.*; Jin, M.*; Ding, J.*; Wu, J.*; Chen, Z.*; Lin, S.*; Fabelo, O.*; Rodriguez-Velamazan, J. A.*; 古府 麻衣子; et al.
Nature Materials, 22(8), p.999 - 1006, 2023/08
被引用回数:143 パーセンタイル:99.28(Chemistry, Physical)Ultralow thermal conductivity and fast ionic diffusion endow superionic materials with excellent performance both as thermoelectric converters and as solid-state electrolytes. Yet the correlation and interdependence between these two features remain unclear owing to a limited understanding of their complex atomic dynamics. Here we investigate ionic diffusion and lattice dynamics in argyrodite Ag
SnSe
using synchrotron X-ray and neutron scattering techniques along with machine-learned molecular dynamics. We identify a critical interplay of the vibrational dynamics of mobile Ag and a host framework that controls the overdamping of low-energy Ag-dominated phonons into a quasi-elastic response, enabling superionicity. Concomitantly, the persistence of long-wavelength transverse acoustic phonons across the superionic transition challenges a proposed 'liquid-like thermal conduction' picture. Rather, a striking thermal broadening of low-energy phonons, starting even below 50 K, reveals extreme phonon anharmonicity and weak bonding as underlying features of the potential energy surface responsible for the ultralow thermal conductivity (
0.5 Wm
K
) and fast diffusion. Our results provide fundamental insights into the complex atomic dynamics in superionic materials for energy conversion and storage.
Kodeli, I. A.*; Fleming, M.*; Cabellos, O.*; Leal, L.*; Celik, Y.*; Ding, Y.*; Jansky, B.*; Neudecker, D.*; Novak, E.*; Simakov, S.*; et al.
EPJ Web of Conferences, 284, p.15002_1 - 15002_8, 2023/05
被引用回数:3 パーセンタイル:86.28(Nuclear Science & Technology)経済協力開発機構原子力機関(OECD/NEA)において、放射線遮蔽積分ベンチマークアーカイブ及びデータベース(SINBAD)の利用促進とSINBAD評価活動への還元を目的として、国際核データ評価協力サブグループ47(WPEC SG47)「核データ検証のためのSINBADの利用」が2019年6月に立ち上がった。SINBADでは、核データ及び放射線輸送計算コードの検証と開発におけるニーズに合致した実験データベースの評価と保存を進めている。その中で、WPEC SG47の活動においては、SINBAD評価活動における核データの感度解析の利用、実験体系を再現する形状、放射線源、材料等のCAD情報のSINBADへの格納、OECD/NEAのソフトウェアGitLabを利用した様々な放射線輸送計算コードの入力ファイルの共有等について議論や提案が進められている。この活動中に約8例のベンチマーク実験データが核データの検証に利用され、今後、高崎量子応用研究所イオン照射研究施設(TIARA)で実施された中性子遮蔽実験を含む様々な実験データも核データの検証で利用される予定である。本発表では、WPEC SG47の活動の他、SINBADの核データ評価への利用例と評価活動計画について紹介する。
-decay branching ratio of
PtCubiss, J. G.*; Harding, R. D.*; Andreyev, A. N.; Althubiti, N.*; Andel, B.*; Antalic, S.*; Barzakh, A. E.*; Cocolios, T. E.*; Day Goodacre, T.*; Farooq-Smith, G. J.*; et al.
Physical Review C, 101(1), p.014314_1 - 014314_4, 2020/01
被引用回数:5 パーセンタイル:38.25(Physics, Nuclear)
Ptの基底状態から娘核
Osの基底状態への
崩壊分岐比を0.52(5)%と、過去の値と比較してより高精度で再決定した。
PtはCERN-ISOLDE実験施設において
Hgを単離し、その
崩壊孫核種として生成した。今回の結果を用いて導出した
崩壊の換算崩壊幅は、中性子欠損Pt同位体の
崩壊幅の系統性について新しい描像を与えることとなった。
decay of
USun, M. D.*; Liu, Z.*; Huang, T. H.*; Zhang, W. Q.*; Andreyev, A. N.; Ding, B.*; Wang, J. G.*; Liu, X. Y.*; Lu, H. Y.*; Hou, D. S.*; et al.
Physics Letters B, 800, p.135096_1 - 135096_5, 2020/01
被引用回数:15 パーセンタイル:74.74(Astronomy & Astrophysics)Fine structure in the
decay of
U was observed in the fusion-evaporation reaction
Re(
Ar,p3n) by using fast digital pulse processing technique. Two
-decay branches of
U feeding the ground state and 244 keV excited state of
Th were identified by establishing the decay chain
U
Th
Ra
Rn. The
-particle energy for the ground-state to ground-state transition of
U was determined to be 8993(17) keV, 213 keV higher than the previous value, the half-life was updated to be 62
s. Evolution of nuclear structure for
=131 even-
isotones from Po to U was discussed in the frameworks of nuclear mass and reduced
-decay width, a weakening octupole deformation in the ground state of
U relative to its lighter isotones
Ra and
Th was suggested.
=28 and
=50; Spectroscopy of
ZnShand, C. M.*; Podoly
k, Zs.*; G
rska, M.*; Doornenbal, P.*; Obertelli, A.*; Nowacki, F.*; Otsuka, T.*; Sieja, K.*; Tostevin, J. A.*; Tsunoda, T.*; et al.
Physics Letters B, 773, p.492 - 497, 2017/10
被引用回数:34 パーセンタイル:88.68(Astronomy & Astrophysics)Low-lying states in neutron-rich
Zn nuclei were measured for the first time via in-beam
-ray spectroscopy at RIKEN. These include the 4
to 2
in
Zn and the 2
to 0
and 4
to 2
in
Zn. The reduced E(
) energies and increased E(4
)/E(2
) ratios at
=52,54 compared to
Zn attest that the magicity is confined just on the neutron number
=50 only. The levels observed in
Zn suggest the onset of deformation towards heavier Zn isotopes. The data were compared to state-of-the-art shell model calculations.
KrFlavigny, F.*; Doornenbal, P.*; Obertelli, A.*; Delaroche, J.-P.*; Girod, M.*; Libert, J.*; Rodriguez, T. R.*; Authelet, G.*; 馬場 秀忠*; Calvet, D.*; et al.
Physical Review Letters, 118(24), p.242501_1 - 242501_6, 2017/06
被引用回数:49 パーセンタイル:87.22(Physics, Multidisciplinary)The first
-ray spectroscopy of very neutron rich
Kr isotopes was carried out at the RIBF at RIKEN Nishina center. Excited states in these isotopes were populated via (p,2p) reactions using radioactive
Rb beams accelerated to 220 MeV/nucleon. The new data show a significant increase in deformation beyond N=60, as well as competing configurations (shape-coexistence) at low energy. The data were compared with beyond-mean-field calculations which predict level energies in good agreement with observation, and suggest oblate-prolate shape coexistence.
Chen, S.*; Doornenbal, P.*; Obertelli, A.*; Rodriguez, T. R.*; Authelet, G.*; 馬場 秀忠*; Calvet, D.*; Ch
teau, F.*; Corsi, A.*; Delbart, A.*; et al.
Physical Review C, 95(4), p.041302_1 - 041302_6, 2017/04
被引用回数:35 パーセンタイル:89.09(Physics, Nuclear)Neutron-rich isotopes of selenium,
Se, where studied via in beam
-ray spectroscopy after nucleon removal reactions at RIBF in RIKEN. The low-energy excitations of these nuclei were investigated using
-
coincidences, and the first and second excited 2
states were found at remarkably low energies. The analysis and comparison with self-consistent beyond-mean field calculations suggest that both shape coexistence and triaxiality are needed to describe these isotopes.
ZrPaul, N.*; Corsi, A.*; Obertelli, A.*; Doornenbal, P.*; Authelet, G.*; 馬場 秀忠*; Bally, B.*; Bender, M.*; Calvet, D.*; Ch
teau, F.*; et al.
Physical Review Letters, 118(3), p.032501_1 - 032501_7, 2017/01
被引用回数:52 パーセンタイル:88.40(Physics, Multidisciplinary)The first measurement of
rays emitted by the very neutron rich nuclei
Mo (Z=42) and
Zr (Z=40) was carried out at the RIBF facility at RIKEN. These data shine light on the postulated N=70 harmonic oscillator shell. If the spin-orbit splitting which gives rise to the N=82 shell gap is reduced in very neutron-rich nuclei, the harmonic oscillator gap at N=70 should open instead. However, both the measured energy of the first excited state
Mo and
Zr, respectively 235(7) keV and 185(11) keV, and their E(4
)/E(2
) ratio, indicate that these nuclei are good rotors, and exclude the shell stabilization scenario at Z=40 and N=70. These results were compared to state-of-the-art density functional theoretical calculations using Gogny and Skyrme effective interactions.
Frandsen, B. A.*; Liu, L.*; Cheung, S. C.*; Guguchia, Z.*; Khasanov, R.*; Morenzoni, E.*; Munsie, T. J. S.*; Hallas, A. M.*; Wilson, M. N.*; Cai, Y.*; et al.
Nature Communications (Internet), 7, p.12519_1 - 12519_8, 2016/08
被引用回数:43 パーセンタイル:78.05(Multidisciplinary Sciences)RENiO
(RE = rare-earth element) and V
O
are archetypal Mott insulator systems. When tuned by chemical substitution (RENiO
) or pressure (V
O
), they exhibit a quantum phase transition (QPT) between an antiferromagnetic Mott insulating state and a paramagnetic metallic state. Because novel physics often appears near a Mott QPT, the details of this transition, such as whether it is first or second order, are important. Here, we demonstrate through muon spin relaxation/rotation experiments that the QPT in RENiO
and V
O
is first order: the magnetically ordered volume fraction decreases to zero at the QPT, resulting in a broad region of intrinsic phase separation, while the ordered magnetic moment retains its full value until it is suddenly destroyed at the QPT. These findings bring to light a surprising universality of the pressure-driven Mott transition, revealing the importance of phase separation and calling for further investigation into the nature of quantum fluctuations underlying the transition.
c characteristics in PIT wires based on BaFe
As
with different substitutions為ヶ井 強*; Pyon, S.*; Ding, Q. P.*; 井上 啓*; 小林 啓紀*; 土屋 雄司*; Sun, Y.*; 梶谷 秀樹; 小泉 徳潔
Journal of Physics; Conference Series, 507(2), p.022041_1 - 022041_4, 2014/05
被引用回数:3 パーセンタイル:73.81(Engineering, Electrical & Electronic)鉄系超伝導体において、化合物の臨界電流密度(
c)への影響を調査した。この中で、(Ba,K)Fe
As,P2及びBa(Fe,Co)
As
が、比較的高いJcを示すことが分かった。さらに、これらの線に、120MPa, 600
Cの等方圧加熱接合(HIP)処理を施すことで、さらに
cを向上でき、最大で32,000A/cm
(4.2K)と、従来の
cに比べて一桁以上高いJcを得ることができた。
spectroscopy of the even-even nucleus
PtLi, G. S.*; Liu, M. L.*; Zhou, X. H.*; Zhang, Y. H.*; Liu, Y. X.*; Zhang, N. T.*; Hua, W.*; Zheng, Y. D.*; Fang, Y. D.*; Guo, S.*; et al.
Physical Review C, 89(5), p.054303_1 - 054303_9, 2014/05
被引用回数:6 パーセンタイル:35.16(Physics, Nuclear)タンデム加速器で88MeVにまで加速された
Oビームを用いて
Yb(
O, 4
)反応を起こし、
Ptの高スピン準位を調べた。その結果、
1(ここで
は
もしくは
)配位による正パリティバンドを大幅に拡張するとともに新しく負パリティバンドを同定し、
配位を持つことを明らかにした。また、イラスト準位においてスピンの増加に伴い振動から回転へと構造変化を起こしている可能性について議論した。さらにバンド特性を明らかにするためにTotal Routhian surface計算を行った。
WWang, H. X.*; Zhang, Y. H.*; Zhou, X. H.*; Liu, M. L.*; Ding, B.*; Li, G. S.*; Hua, W.*; Zhou, H. B.*; Guo, S.*; Qiang, Y. H.*; et al.
Physical Review C, 86(4), p.044305_1 - 044305_11, 2012/10
被引用回数:6 パーセンタイル:34.79(Physics, Nuclear)High-spin states in
W have been studied using the
Nd(
Si,5
)
W reaction at beam energies of 135 and 140 MeV. The previously known bands associated with the 7/2
[633], 5/2
[512], and 1/2
[521] configurations are extended significantly, and the unfavored signature branch of the 1/2
[521] band is established for the first time. The band properties, such as level spacings, band-crossing frequencies, alignment gains, and signature splittings, are discussed with an emphasis on the low-spin signature inversion observed in the 5/2
[512] band. By comparing the experimental
(
1)/
(
2) ratios with the theoretical values, we conclude that the configuration of the 5/2
[512] band is quite pure at low spins without appreciable admixture of the 5/2
[523] orbit, in conflict with the particle rotor model calculated results.
PdZhou, H. B.*; Zhou, X. H.*; Zhang, Y. H.*; Zheng, Y.*; Liu, M. L.*; Zhang, N. T.*; Chen, L.*; Wang, S. T.*; Li, G. S.*; Wang, H. X.*; et al.
European Physical Journal A, 47(9), p.107_1 - 107_7, 2011/09
被引用回数:7 パーセンタイル:43.71(Physics, Nuclear)
Pd原子核の高スピン状態を、タンデム加速器及び多重
線検出装置GEMINI-IIを用いて、インビーム
線核分光法で調べた。既知の
バンド, 1/2
[550]バンドをより高スピン状態まで拡張した。発見されたバンド交差は
陽子の整列によるものであると解釈した。
Pdの回転バンドの性質を周辺の核、及びcranked shell modelと比較・議論した。
[503] band of
PtLi, G. S.*; Zhou, X. H.*; Zhang, Y. H.*; Zheng, Y.*; Liu, M. L.*; Hua, W.*; Zhou, H. B.*; Ding, B.*; Wang, H. X.*; Lei, X. G.*; et al.
Journal of Physics G; Nuclear and Particle Physics, 38(9), p.095105_1 - 095105_9, 2011/09
被引用回数:1 パーセンタイル:11.09(Physics, Nuclear)
Ptの高スピン状態をタンデム加速器と多重
線検出装置GEMINI-IIを用いて調べた。低スピン指標逆転現象が7/2
[503]バンドで観測された。この現象は、中性子が7/2
[503]軌道から7/2
[514]軌道に移ることによって起こるという解釈は、DonauとFrauendorfの反古典的近似による計算結果によって支持された。
Lu, L.*; 飯田 浩正; Li, Y.*; Ding, A.*; Zeng, Q.*; Huang, C.*; Wu, Y.*
no journal, ,
ポートリミターはITER(国際熱核融合炉)の重要な機器の一つであり、非常に複雑な形状を持っている。CAD図面から自動的にモンテカルロコードMCNPの入力を作成するプログラムMCAMを用いて、核解析を行うための詳細な入力を作成した。本発表は元図であるCAD図面のpreprocess及び変換された入力のvalidationの詳細なフローについて述べたものである。本作業が成功裏に行われたことは、複雑な機器のモンテカルロコード用入力を作成することにおいて、MCAMが、従来のマニュアル作業による入力作成に比べ、圧倒的に効率を高め、また正確さを増すことができることを示すものである。
Ding, F.*; 芦川 直子*; 福本 正勝; 片山 一成*; Mao, H.*; Ding, R.*; Xu, Q.*; Wu, J.*; Xie, C. Y.*; Luo, G.-N.*
no journal, ,
Castellated tungsten samples with different gap width and gap depth are exposed to the scrape-off-layer plasma with the material and plasma evaluation system (MAPES) to investigate effects of castellation configurations on impurity deposition and fuel retention. After the plasma exposure, composition and distribution of the impurity deposited on the inner surface of the gap are investigated. The composition and the distribution of the deposits have a strong dependence of the gap configuration. The amount of the deposits on the inner surface of the inverse trapezoid gap is small compared with that of the rectangular gap with the same top width. For all the samples, the amount of the deposits decreases with the gap width and depth.