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Yang, X.*; Che, G.*; Wang, Y.*; Zhang, P.*; Tang, X.*; Lang, P.*; Gao, D.*; Wang, X.*; Wang, Y.*; 服部 高典; et al.
Nano Letters, 25(3), p.1028 - 1035, 2025/01
被引用回数:1 パーセンタイル:84.76(Chemistry, Multidisciplinary)飽和sp-カーボンナノスレッド(CNTh)は、その高いヤング率と熱伝導率が予測され、大きな関心を集めている。中心環へのヘテロ原子の導入がCNThの形成に影響を与え、化学的に均質な生成物が得られることが示されているが、ペンダント基が重合プロセスに与える影響については、まだ未解明である。本研究では、フェノールの圧力誘起重合を調べ、0.5GPaと4GPa以下で起こる2つの相転移を明らかにした。20GPa以上では、フェノールは水酸基とカルボニル基を持つ重合度4のCNTに重合する。ヒドロキシル基の水素移動は、重合度6のナノスレッドの形成を妨げることがわかった。この発見は、さらなるカラム内重合を阻止する水酸基の重要な役割を浮き彫りにし、今後のメカニズム研究やナノ材料合成に貴重な示唆を与えるものである。
Che, G.*; Fei, Y.*; Tang, X.*; Zhao, Z.*; 服部 高典; 阿部 淳*; Wang, X.*; Ju, J.*; Dong, X.*; Wang, Y.*; et al.
Physical Chemistry Chemical Physics, 27(2), p.1112 - 1118, 2025/01
被引用回数:3 パーセンタイル:75.15(Chemistry, Physical)芳香族分子の圧力誘起重合(PIP)は、様々な炭素系材料を合成するための効果的な方法として浮上してきた。目的とする構造や機能を得るためには、適切な官能基化された分子前駆体の選択が極めて重要である。本研究では、1,4-ジフルオロベンゼン(1,4-DFB)をPIPの構成要素として選択した。1,4-DFBをその場高圧で調べた結果、約12.0GPaで相転移が起こり、18.7GPaで不可逆的な化学反応が起こることがわかった。生成物の構造解析と反応のカイネティクスから、直線的な成長を伴う擬六方晶積層フッ素ダイヤモンドナノスレッドの形成が明らかになった。高圧下のベンゼンの結晶構造と比較して、1,4-DFBは[001]軸に沿って高い圧縮を示す。この異方的な圧縮は、[01]軸に沿ったより強いH
相互作用と、[100]軸と[010]軸に沿った潜在的な圧縮阻害H
F相互作用に起因し、[01
]軸に沿った可能な反応経路を促進する。この研究は、分子スタッキングを調節し、反応経路に影響を与える官能基化の重要な役割を強調している。
Wang, S.*; Wang, J.*; Zhang, S.*; Wei, D.*; Chen, Y.*; Rong, X.*; Gong, W.; Harjo, S.; Liu, X.*; Jiao, Z.*; et al.
Journal of Materials Science & Technology, 185, p.245 - 258, 2024/06
被引用回数:17 パーセンタイル:98.00(Materials Science, Multidisciplinary)Nanoprecipitates and nanoscale retained austenite (RA) with suitable stability play crucial roles in determining the yield strength (YS) and ductility of ultrahigh strength steels (UHSSs). However, owing to the kinetics incompatibility between nanoprecipitation and austenite reversion, it is highly challenging to simultaneously introduce high-density nanoprecipitates and optimized RA in UHSSs. In this work, through the combination of austenite reversion treatment (ART) and subsequent flash austenitizing (FA), nanoscale chemical heterogeneity was successfully introduced into a low-cost UHSS prior to the aging process. This chemical heterogeneity involved the enrichment of Mn and Ni in the austenite phase. The resulting UHSS exhibited dual-nanoprecipitation of Ni(Al,Mn) and (Mo,Cr) C and nanoscale austenite stabilized via Mn and Ni enrichment. The hard martensitic matrix strengthened by high-density dual-nanoprecipitates constrains the plastic deformation of soft RA with a relatively low fraction, and the presence of relatively stable nanoscale RA with adequate Mn and Ni enrichment leads to a marginal loss in YS but keeps a persistent transformation-induced plasticity (TRIP) effect. As a result, the newly-developed UHSS exhibits an ultrahigh YS of 1.7 GPa, an ultimate tensile strength (UTS) of 1.8 GPa, a large uniform elongation (UE) of 8.5 percent, and a total elongation (TE) of 13 percent. The strategy of presetting chemical heterogeneity to introduce proper metastable phases before aging can be extended to other UHSSs and precipitation-hardened alloys.
水野 るり恵*; 新倉 潤*; 齋藤 岳志*; 松崎 禎市郎*; 櫻井 博儀*; Amato, A.*; 浅利 駿介*; Biswas, S.*; Chiu, I.-H.; Gianluca, J.*; et al.
Nuclear Instruments and Methods in Physics Research A, 1060, p.169029_1 - 169029_14, 2024/03
被引用回数:2 パーセンタイル:43.92(Instruments & Instrumentation)We have developed a photon detection system for muonic X-ray spectroscopy. The detector system consists of high-purity germanium detectors with BGO Compton suppressors. The signals from the detectors are readout with a digital acquisition system. The absolute energy accuracy, energy and timing resolutions, photo-peak efficiency, the performance of the Compton suppressor, and high count rate durability are studied with standard -ray sources and in-beam experiment using
Al(
)
Si resonance reaction. The detection system was demonstrated at Paul Scherrer Institute. A calibration method for a photon detector at a muon facility using muonic X-rays of
Au and
Bi is proposed.
Huang, Z.*; Wang, W.*; Ye, H.*; Bao, S.*; Shangguan, Y.*; Liao, J.*; Cao, S.*; 梶本 亮一; 池内 和彦*; Deng, G.*; et al.
Physical Review B, 109(1), p.014434_1 - 014434_9, 2024/01
被引用回数:3 パーセンタイル:57.35(Materials Science, Multidisciplinary)TbMnSn
is a correlated topological magnet with a Mn-based kagome lattice, in which a Chern gap opens at the Dirac point at low temperatures. The magnetic moment direction of the ferrimagnetic order changes from in the kagome plane to the out-of-plane upon cooling, which is essential for generating the Chern gap, but the underlying mechanism for the spin reorientation remains elusive. Here, we investigate the spin-reorientation transition in TbMn
Sn
using neutron scattering. We provide direct evidence for the spin-reorientation transition and unveil the coexistence of two Tb modes at 200 K. To account for these results, we put forward a model based on SU(N) spin-wave theory, in which there is a temperature evolution of the ground state Tb
orbitals, driven by the crystalline electric field, single-ion anisotropy, and exchange interactions between Tb and Mn ions. Our findings shed light on the complex magnetism of TbMn
Sn
, despite its relatively simple ground state magnetic structure, and provide insights into the mechanisms for tuning magnetic topological materials.
Zhang, A.*; Deng, K.*; Sheng, J.*; Liu, P.*; Kumar, S.*; 島田 賢也*; Jiang, Z.*; Liu, Z.*; Shen, D.*; Li, J.*; et al.
Chinese Physics Letters, 40(12), p.126101_1 - 126101_8, 2023/12
被引用回数:11 パーセンタイル:85.96(Physics, Multidisciplinary)In a Dirac semimetal, the massless Dirac fermion has zero chirality, leading to surface states connected adiabatically to a topologically trivial surface state as well as vanishing anomalous Hall effect. Recently, itis predicted that in the nonrelativistic limit of certain collinear antiferromagnets, there exists a type of chiral "Dirac-like" fermion, whose dispersion manifests four-fold degenerate crossing points formed by spin-degenerate linear bands, with topologically protected Fermi arcs. Here, by combining with neutron diffraction and first-principles calculations, we suggest a multidomain collinear antiferromagnetic configuration, rendering the existence of the Fermi-arc surface states induced by chiral Dirac-like fermions.
Wang, G.-J.*; 岡 眞*; 慈道 大介*
Physical Review D, 108(7), p.L071501_1 - L071501_6, 2023/10
被引用回数:10 パーセンタイル:76.22(Astronomy & Astrophysics)QCDの弦描像によって、新しい閉じ込めメカニズムを提案した内容を報告する。
近藤 洋介*; Achouri, N. L.*; Al Falou, H.*; Atar, L.*; Aumann, T.*; 馬場 秀忠*; Boretzky, K.*; Caesar, C.*; Calvet, D.*; Chae, H.*; et al.
Nature, 620(7976), p.965 - 970, 2023/08
被引用回数:29 パーセンタイル:95.28(Multidisciplinary Sciences)非常に中性子が過剰な原子核Oは、陽子、中性子ともに魔法数であることから古くからその性質に興味が持たれていたが、酸素の最後の束縛核
Oよりも中性子が4個も多いため、これまで観測されてこなかった。この論文では、理化学研究所RIBFにて
Fからの1陽子ノックアウト反応によって
Oを生成し、そこから放出される中性子を測定することによって初めてその観測に成功した。核構造の観点からは、
Oでは二重閉殻が保たれているか興味が持たれていたが、実験で得られた分光学的因子が殻模型計算で予言されて程度の大きいことから、閉殻構造をもたない可能性が高いことがわかった。
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:78 パーセンタイル:99.19(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 AgSnSe
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.
Chen, S.*; Browne, F.*; Doornenbal, P.*; Lee, J.*; Obertelli, A.*; 角田 佑介*; 大塚 孝治*; 茶園 亮樹*; Hagen, G.*; Holt, J. D.*; et al.
Physics Letters B, 843, p.138025_1 - 138025_7, 2023/08
被引用回数:9 パーセンタイル:89.00(Astronomy & Astrophysics)Scからの1陽子ノックアウト反応を用いて、
Caと
Caのガンマ崩壊を観測した。
Caでは1456(12)keVの
線遷移が、
Caでは1115(34)keVの遷移が観測された。どちらの遷移も暫定的に
と割り当てられた。有効核子間相互作用をわずかに修正した広い模型空間での殻模型計算では、
準位エネルギー、2中性子分離エネルギー、反応断面積が実験とよく一致し、N=34閉殻の上に新しい殻が形成されていることを裏付けた。その構成要素である
と
軌道はほぼ縮退しており、これは
Caが二重魔法核である可能性を排除し、Ca同位体のドリップラインを
Caあるいはそれ以上にまで広げる可能性がある。
Meng, L.*; Wang, B.*; Wang, G.-J.*; Zhu, S.-L.*
Physics Reports; A Review Section of Physics Letters, 1019, p.1 - 149, 2023/05
被引用回数:127 パーセンタイル:97.56(Physics, Multidisciplinary)Chiral symmetry and its spontaneous breaking play an important role both in the light hadron and heavy hadron systems. The chiral perturbation theory (PT) is the low energy effective field theory of the Quantum Chromodynamics. In this work, we shall review the investigations on the chiral corrections to the properties of the heavy mesons and baryons within the framework of
PT. We will also review the scatterings of the light pseudoscalar mesons and heavy hadrons, through which many new resonances such as the D*s0(2317) could be understood. Moreover, many new hadron states were observed experimentally in the past decades. A large group of these states is near-threshold resonances, such as the charged charmoniumlike
and
states, bottomoniumlike
states, hidden-charm pentaquark
and
states and the doubly charmed
state, etc. They are very good candidates of the loosely bound molecular states composed of a pair of charmed (bottom) hadrons, which are very similar to the loosely bound deuteron. The modern nuclear force was built upon the chiral effective field theory (LEFT), which is the extension of the
PT to the systems with two matter fields. The long-range and medium-long-range interactions between two nucleons arise from the single-and double-pion exchange respectively, which are well constrained by the chiral symmetry and its spontaneous breaking. The short-distance interactions can be described by the low energy constants. Such a framework works very well for the nucleon-nucleon scattering and nuclei. In this work, we will perform an extensive review of the progress on the heavy hadronic molecular states within the framework of LEFT. We shall emphasize that the same chiral dynamics not only govern the nuclei and forms the deuteron, but also dictates the shallow bound states or resonances composed of two heavy hadrons.
Yang, Z.*; Wang, G.-J.*; Wu, J.-J.*; 岡 眞; Zhu, S.-L.*
Journal of High Energy Physics (Internet), 2023(1), p.058_1 - 058_19, 2023/01
被引用回数:10 パーセンタイル:76.22(Physics, Particles & Fields)ハミルトニアン有効理論にクォーク模型、クォークペア生成、相互作用の情報を含むベアな状態と散乱状態の結合を取り入れた形式を用いて、しきい値近傍の
波の4個の
状態のスペクトルを研究した。
Sheng, J.*; Wang, L.*; Candini, A.*; Jiang, W.*; Huang, L.*; Xi, B.*; Zhao, J.*; Ge, H.*; Zhao, N.*; Fu, Y.*; et al.
Proceedings of the National Academy of Sciences of the United States of America, 119(51), p.e2211193119_1 - e2211193119_9, 2022/12
被引用回数:34 パーセンタイル:93.63(Multidisciplinary Sciences)Although considerable progress has been made in the theoretical understanding of the low-dimensional frustrated quantum magnets, experimental realizations of a well-established scaling analysis are still scarce. This is particularly true for the two-dimensional antiferromagnetic triangular lattices. Owing to the small exchange strength, the newly discovered compound NaBaCo(PO
)
provides a rare opportunity for clarifying the quantum criticality in an ideal triangular lattice with quantum spin S=1/2. In addition to the establishment of the complete phase diagrams, the spin Hamiltonian with a negligible interplane interaction has been determined through the spin wave dispersion in the polarized state, which is consistent with the observation of a two-dimensional quantum critical point with the Bose-Einstein condensation of diluted free bosons.
Wang, G.-J.*; Meng, Q.*; 岡 眞
Physical Review D, 106(9), p.096005_1 - 096005_9, 2022/11
被引用回数:30 パーセンタイル:93.08(Astronomy & Astrophysics)クォーク模型を用いて、チャームクォークの4体系であるテトラクォークのS波の共鳴状態の探索を行った。複素スケーリング法を用いた計算でスピンーパリティが,
,
の各チャネルに2個ずつ共鳴が存在することを明らかにした。しかし、これらの共鳴は最近の実験で見つかった
と比べると100MeV近く高いところに存在していることが解った。
Zhang, M. M.*; Tian, Y. L.*; Wang, Y. S.*; Zhang, Z. Y.*; Gan, Z. G.*; Yang, H. B.*; Huang, M. H.*; Ma, L.*; Yang, C. L.*; Wang, J. G.*; et al.
Physical Review C, 106(2), p.024305_1 - 024305_6, 2022/08
被引用回数:5 パーセンタイル:60.14(Physics, Nuclear)The extremely neutron-deficient even-even uranium isotopes U were produced in the complete-fusion reactions induced by impinging
Ar and
Ca ions on
W targets. Fusion evaporation residues were separated in flight by the gas-filled recoil separator SHANS (Spectrometer for Heavy Atoms and Nuclear Structure) and subsequently identified using the recoil-
-correlation method. In this paper, we report on new
-decay activities with
keV for
U and
keV for
U, which decay from the 8
isomeric states of
U into the 2
states of their daughter nuclei
Th, respectively. The new results extend the systematics of the
-decay fine structure for the
= 124 and 126 even-even isotones.
Thiessen, K. M.*; Boznar, M. Z.*; Charnock, T. W.*; Chouhan, S. L.*; Federspiel, L.; Grai
, B.*; Grsic, Z.*; Helebrant, J.*; Hettrich, S.*; Hulka, J.*; et al.
Journal of Radiological Protection, 42(2), p.020502_1 - 020502_8, 2022/06
被引用回数:5 パーセンタイル:60.29(Environmental Sciences)The IAEA's model testing programmes (1988-2019) have included a series of Working Groups concerned with modelling radioactive contamination in urban environments. This paper describes the exercises conducted during the MODARIA I (2012-2015) and MODARIA II (2016-2019) programmes. These exercises have included short-range and mid-range atmospheric dispersion exercises based on data from field tests or tracer studies, hypothetical urban dispersion exercises, and an exercise based on data collected after the Fukushima accident. Improvement of model capabilities will lead to improvements in assessing various contamination scenarios (real or hypothetical), and in turn, to improved decision-making and communication with the public following a nuclear or radiological emergency.
Yang, Z.*; Wang, G.-J.*; Wu, J.-J.*; 岡 眞; Zhu, S.-L.*
Physical Review Letters, 128(11), p.112001_1 - 112001_6, 2022/03
被引用回数:40 パーセンタイル:95.41(Physics, Multidisciplinary)閾値近傍のハドロン共鳴を有限サイズの格子QCDのデータを用いて解析する新しい手法を提案し、正パリティのメソンのスペクトルに応用した。ハミルトニアン有効理論にクォーク模型,クォークペア生成,DK相互作用の情報を入れてベアな状態と散乱状態の結合を取り入れた。4個の
状態のうち、
と
の状態は散乱状態と強く混合する。一方で、
と
はほとんどベアなクォーク模型状態で記述できる。有限格子サイズでのレベル交差が再現されることを示した。
Meng, L.*; Wang, G.-J.*; Wang, B.*; Zhu, S.-L.*
Physical Review D, 104(9), p.094003_1 - 094003_8, 2021/11
被引用回数:28 パーセンタイル:85.89(Astronomy & Astrophysics)共鳴のアイソスピンを破る崩壊について再解析を行った。その結果
の内部構造と崩壊におけるアイソスピンの破れを定量的に結びつける新しい解析方法を提案し、これを適用した。その結果、
における中性メソンチャネルの寄与が80%であることがわかった。
Yan, S. Q.*; Li, X. Y.*; 西尾 勝久; Lugaro, M.*; Li, Z. H.*; 牧井 宏之; Pignatari, M.*; Wang, Y. B.*; Orlandi, R.; 廣瀬 健太郎; et al.
Astrophysical Journal, 919(2), p.84_1 - 84_7, 2021/10
被引用回数:5 パーセンタイル:33.27(Astronomy & Astrophysics)The long-lived Fe (with a half-life of 2.62 Myr) is a crucial diagnostic of active nucleosynthesis in the Milky Way galaxy and in supernovae near the solar system. The neutron-capture reaction
Fe(n,
)
Fe on
Fe (half-life=44.5 days) is the key reaction for the production of
Fe in massive stars. This reaction cross section has been previously constrained by the Coulomb dissociation experiment, which offered partial constraint on the E1
-ray strength function but a negligible constraint on the M1 and E2 components. In this work, for the first time, we use the surrogate ratio method to experimentally determine the
Fe(n,
)
Fe cross sections in which all the components are included. We derived a Maxwellian-averaged cross section of 27.5
3.5 mb at
= 30 keV and 13.4
1.7 mb at
= 90 keV, roughly 10%-20% higher than previous estimates. We analyzed the impact of our new reaction rates in nucleosynthesis models of massive stars and found that uncertainties in the production of
Fe from the
Fe(n,
)
Fe rate are at most 25
. We conclude that stellar physics uncertainties now play a major role in the accurate evaluation of the stellar production of
Fe.
Meng, L.*; Wang, B.*; Wang, G.-J.*; Zhu, S.-L.*
Science Bulletin, 66(20), p.2065 - 2071, 2021/10
被引用回数:28 パーセンタイル:85.10(Multidisciplinary Sciences)最近発見された2つのテトラクォーク状態(3985)と
(4000)の崩壊を有効理論を用いて調べた結果、崩壊の分岐比からこれらが同じ状態か異なる状態かを判断できることがわかった。