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Xue, J.*; Huang, D.*; 服部 高典; Li, L.*; Feng, Y.*; Wang, H.*; Fan, X.*; Yao, J.*; Wang, Y.*; Liu, Z.*; et al.
Applied Physics Letters, 128(20), p.201903_1 - 201903_8, 2026/05
被引用回数:0 パーセンタイル:0.00(Physics, Applied)NH
Iのサイクル疲労およびバロカロリック応答は、最大100MPaの応力を伴う加圧・減圧サイクル下で直接評価され、100サイクルの後に断熱温度変化(
)は15Kから約0.8Kまで減少した。emphその場X線回折、ラマン分光法、および中性子回折を併用した解析により、最初の荷重除去後であっても残留高圧相が存在することが明らかになり、その割合は100サイクル目までに急速に90%まで増加した。この疲労挙動を解明するために現象論的モデルが構築され、実験データとの良好な一致が得られた。粒界応力を緩和し、結晶粒の移動性を高めるため、NH
I粒子とシリコーンオイルからなる複合体を、3Dプリントされたポリマーシェルに封入した。このような構造設計により、バロカロリック効果のサイクル安定性が著しく向上し、100サイクル後でも
は約4.6Kまで上昇した。我々の結果は、気圧熱効果の疲労挙動に関する基礎的な理解を確立するとともに、実用的な気圧熱冷却技術への実現可能な道筋を示すものである。
Li, H.*; Gong, W.; 川崎 卓郎; Harjo, S.; Zheng, R.*; 他6名*
Acta Materialia, 305, p.121884_1 - 121884_10, 2026/02
被引用回数:3 パーセンタイル:84.67(Materials Science, Multidisciplinary)The quest for lightweight and highly formable magnesium (Mg) alloys has drawn significant attention due to the growing demand for energy-efficient structural materials. Achieving high ductility in Mg at room temperature, which is critical for mass production of structural components, remains a formidable challenge despite decades of research. In this study, we demonstrate super-ductility in an ultrafine-grained (UFG) Mg alloy at room temperature. By microalloying with trace manganese (Mn) and reducing the grain size to sub-micron scale, Mg-0.3Mn binary alloy achieves an exceptional room temperature tensile elongation of 135% at a quasi-static strain rate. Detailed microstructural analysis reveals that grain boundary (GB) sliding, rather than intragranular dislocation slip, is the dominant deformation mechanism in the UFG Mg-0.3Mn alloy. Unlike conventional alloying strategies that lead to GB pinning, the segregation of Mn element along GBs in a manner of nano-clusters could reduce interfacial bonding strength, acting as a lubricant to facilitate GB sliding and thus dramatically boost the ductility. This innovative GB engineering approach unlocks unprecedentedly remarkable deformability of Mg-based alloys at room temperature, paving the way for next-generation lightweight structural applications.
RhZhang, J. Z.*; Chen, Z. Q.*; Qu, T.*; Wang, Y. K.*; Li, Z. H.*; Orlandi, R.; 他62名*
Physics Letters B, 873, p.140144_1 - 140144_9, 2026/02
被引用回数:0 パーセンタイル:0.00(Astronomy & Astrophysics)At the RIKEN,
-delayed
-ray spectroscopy studies were conducted on
Rh and
Rh, resulting in the world's first successful identification of a 1/2
isomer in these isotope, extending the energy difference between the 9/2
and 1/2
states up to neutron number
=74. Comparison of the new results with state-of-the-art calculations suggests that triaxial deformation plays a significant role in the evolution of the energy difference, indicating a shape transition from axially symmetric to triaxial deformation within the Rh isotopic series. These findings provide new insights into the structure of neutron-rich nuclei in the atomic number
region, elucidating the interplay between triaxial deformation and shell evolution.
Fei, Y.*; Wang, Y.*; Zhang, J.*; Liu, J.*; Zhao, Z.*; 服部 高典; 阿部 淳*; Dong, X.*; Mao, H.-K.*; Zheng, H.*; et al.
Chemistry; A European Journal, p.e71096_1 - e71096_11, 2026/00
被引用回数:0 パーセンタイル:0.00(Chemistry, Multidisciplinary)カーボンナノスレッド(CNThs)は、卓越した機械的特性を備えた一次元飽和炭素ナノ材料である。多環芳香族炭化水素(PAHs)は、高圧下において、機械的性能が向上した、より太い多環状CNThsを形成すると期待されている。本研究では、最も単純なPAHであるナフタレンの高圧重合について、複数の最先端手法を用いて体系的に調査した。ナフタレン分子はヘリンボーン状に積層し、20GPa以上ではa-b方向に沿って[4+2]環化付加反応を起こし、一次元CNThを生成した。多くのCNThの形成とは対照的に、CNThの核生成は加圧中に起こりその成長は減圧中に進行するが、これはヘリンボーン状に積層した芳香族化合物に普遍的に見られる現象であると考えられる。得られたCNTh結晶の単位格子が決定され、生成物であるCNThの可能な構造も提案された。本研究は、高圧下におけるナフタレンの重合特性を明らかにし、滑り角が重合経路を決定する上で重要な役割を果たすことを示している。
intergranular lattice strain generated by plastic deformation in ferritic steel友田 陽*; Li, H.*; 土田 紀之*; Gong, W.; Harjo, S.; 大村 孝仁*
Materials Science & Engineering A, 946, p.149136_1 - 149136_12, 2025/11
The uniaxial deformation behavior of low-carbon ferritic steels with grain sizes of 0.47 um and 1.5 um was studied using in situ neutron diffraction under tensile and compressive loading. The evolution of
lattice strains was analyzed in terms of elastic anisotropy and grain-to-grain plastic incompatibility, which generates
intergranular strains. Significant residual intergranular lattice strains were observed after both tensile and compressive plastic deformation. Transmission electron microscopy revealed grain-size-dependent dislocation structures, indicating increasingly constrained plastic relaxation near grain boundaries with grain refinement. Overall, the magnitude of residual
intergranular lattice strains increases as grain size decreases to the submicrometer range.
Ag; Evidence for robustness of
=82 shell closure in silver isotopesLuo, D. W.*; Zhang, J. Z.*; Li, Z. H.*; Orlandi, R.; 他64名*
Physical Review Letters, 134(23), p.232502_1 - 232502_7, 2025/06
被引用回数:4 パーセンタイル:81.47(Physics, Multidisciplinary)The first spectroscopic study of the neutron-rich
Ag isotope at RIBF-RIKEN revealed a new 1.60(7)
s seniority isomer with a proposed 16
spin-parity. Shell model calculations accurately describe its level structure, consistent with seniority schemes in nearby odd-odd nuclei. Level inversions between
Ag and
In's lowest states are linked to seniority-nonconserving interactions. The structure above 10
shows similarities to seniority structures in
Pd and
Cd, confirming the robustness of the
=82 shell closure in silver isotopes.
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:4 パーセンタイル:50.47(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, Y.*; Gong, W.; Su, Y. H.; Li, B.*
Acta Metallurgica Sinica, 60(8), p.1001 - 1016, 2024/08
被引用回数:3 パーセンタイル:31.61(Metallurgy & Metallurgical Engineering)The correlation between the atomic structure, microstructure, and macroscopic properties of structural materials remains a core issue in materials research. In recent years, substantial progress has been achieved in constructing accelerator-based neutron sources and related experimental techniques, offering a robust platform for an in-depth understanding of the aforementioned correlation under real-time and in situ conditions. This article reviews the latest advancements in the application of major neutron characterization techniques, including neutron diffraction, Bragg-edge imaging, small-angle neutron scattering, pair distribution function analysis, and quasi-elastic/inelastic neutron scattering, in structural materials. Furthermore, it particularly highlights the origins and evolution of internal stresses during the phase transformations of steels, deformation mechanisms in light metals such as magnesium alloys, and microstructure and residual stress analyses using Bragg-edge imaging. Finally, a brief outlook on future development trends is provided.
Zeng, Z.*; Zhou, C.*; Zhou, H.*; Han, L.*; Chi, R.*; Li, K.*; 古府 麻衣子; 中島 健次; Wei, Y.*; Zhang, W.*; et al.
Nature Physics, 20(7), p.1097 - 1102, 2024/07
被引用回数:30 パーセンタイル:96.04(Physics, Multidisciplinary)Emergent quasiparticles with a Dirac dispersion in condensed matter systems can be described by the Dirac equation for relativistic electrons, in analogy with Dirac particles in high-energy physics. For example, electrons with a Dirac dispersion have been intensively studied in electronic systems such as graphene and topological insulators. However, charge is not a prerequisite for Dirac fermions, and the emergence of Dirac fermions without a charge degree of freedom has been theoretically predicted to be realized in Dirac quantum spin liquids. These quasiparticles carry a spin of 1/2 but are charge-neutral and so are called spinons. Here we show that the spin excitations of a kagome antiferromagnet, YCu
(OD)
Br
[Br
(OD)
], are conical with a spin continuum inside, which is consistent with the convolution of two Dirac spinons. The predictions of a Dirac spin liquid model with a spinon velocity obtained from spectral measurements are in agreement with the low-temperature specific heat of the sample. Our results, thus, provide spectral evidence for a Dirac quantum spin liquid state emerging in this kagome lattice antiferromagnet. However, the locations of the conical spin excitations differ from those calculated by the nearest-neighbor Heisenberg model, suggesting the Dirac spinons have an unexpected origin.
- and
-processes following
-process in the collapsar jetHe, Z.*; 梶野 敏貴*; 日下部 元彦*; Zhou, S.-G.*; 小浦 寛之; 千葉 敏*; Li, H.*; Lin, Y.*
Astrophysical Journal Letters, 966(2), p.L37_1 - L37_7, 2024/05
被引用回数:9 パーセンタイル:70.80(Astronomy & Astrophysics)The slow and intermediate neutron-capture processes,
- and
-processes, are believed to occur in asymptotic giant branch stars to provide half of the heavy atomic nuclei with A
. We suggest a possibility that certain types of outflows found in the collapsar, which is a supernova generated by a rapidly rotating massive star undergoing core collapse, leaving behind a black hole and emitting relativistic jets, can provide conditions that are viable for
- and
-processes as secondary processes following the rapid neutron-capture process,
-process. We propose that the pronounced odd-even effect in the mass abundance pattern near rare earth elements in metal-deficient halo stars could be an observational hint for the
- and
-processes in the collapsar.
Sn
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:6 パーセンタイル:51.45(Materials Science, Multidisciplinary)TbMn
Sn
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.
X-ray synchrotron diffractionLi, H.*; Liu, Y.*; Zhao, W.*; Liu, B.*; 冨永 亜希; 菖蒲 敬久; Wei, D.*
International Journal of Plasticity, 165, p.103612_1 - 103612_20, 2023/06
被引用回数:51 パーセンタイル:97.50(Engineering, Mechanical)コバルトフリーのマルエージング鋼の強度特性を明らかにするために、高エネルギー放射光X線回折法を利用したその場引張試験を行った。マルテンサイト相とオーステナイト相からの回折プロファイルが得られ、それらの強度及び幅が負荷に伴い変化している様子が観察された。回折プロファイルを解析した結果、時効(as-aged)材では、低応力レベルにてマルテンサイトの含有量が緩やかに減少し、高応力レベルでは急激に減少した。一方、熱処理(as-solution)材では、応力の増加とともにオーステナイト相がマルテンサイト相に著しく転移変態している結果が得られた。これらのことがそれぞれの強度特性に起因していることを明らかにした。
Fe
intermetallic compoundCao, Y.*; Zhou, H.*; Khmelevskyi, S.*; Lin, K.*; Avdeev, M.*; Wang, C.-W.*; Wang, B.*; Hu, F.*; 加藤 健一*; 服部 高典; et al.
Chemistry of Materials, 35(8), p.3249 - 3255, 2023/04
被引用回数:9 パーセンタイル:50.17(Chemistry, Physical)静水圧や化学圧力は、結晶構造を変化させる効率的な刺激であり、材料科学において電気的、磁気的特性のチューニングによく利用されている。しかし、化学圧力は定量化が困難であり、これら両者の定量的な対応関係はまだよくわかっていない。本研究では、負の熱膨張(NTE)を持つ永久磁石の候補である金属間化合物を調べた。放射光X線その場観察により、AlをドープしたHo
Fe
に負の化学圧力があることを明らかにし、単位セル体積の温度・圧力依存性を用いそれを定量的に評価した。また、磁化測定と中性子回折測定を組み合わせることで、磁気秩序に対する化学圧力と静水圧の違いを比較した。興味深いことに、圧力はNTEの抑制と増強を制御するために使用することができた。電子状態計算から、圧力がFermiレベル(EF)に対する主要バンドの上部に影響を与えたことを示しており、これは磁気安定性に影響を与え、それが磁気とNTEを調節する上で重要な役割を果たしていることがわかった。本研究は、圧力の影響を理解し、それを利用して機能性材料の特性を制御する良い例を示している。
frameworks下川 航平*; 畠山 拓也*; Li, H.*; 市坪 哲
Current Opinion in Electrochemistry, 38, p.101209_1 - 101209_8, 2023/04
被引用回数:11 パーセンタイル:23.11(Chemistry, Physical)A wide variety of crystal structures for MnO
is promising for basic frameworks of cathode materials in next-generation batteries such as Mg rechargeable batteries. In this short review, recent progress on MnO
-based cathode materials for Mg rechargeable batteries is summarized, especially focusing on the structures of the polymorphs,
-MnO
and
-MnO
, to discuss the criteria for achieving topotactic reactions during magnesiation.
Ye, X.*; 下川 航平*; 毛塚 有飛*; 畠山 拓也*; Li, H.*; 市坪 哲
Journal of Physical Chemistry C, 127(11), p.5210 - 5218, 2023/03
被引用回数:3 パーセンタイル:17.01(Chemistry, Physical)In this study, wide-range compositions in Mg-Zn-Mn oxide systems were investigated to understand its phase stability for the development of high-energy-density rechargeable Mg batteries. The obtained results showed that the stability of the spinel structure can be significantly improved by compositionally incorporating stable XO (X = Zn, Mg) with
-MnO
. In particular, (i) the equimolar mixing of XO and MnO
is essential to obtain a single-phase cubic spinel structure and (ii) a higher Zn/Mg ratio is effective for preventing the formation of an irreversible rock salt phase to decrease the overpotential during discharge/charge cycling.
Jiang, X.*; 服部 高典; Xu, X.*; Li, M.*; Yu, C.*; Yu, D.*; Mole, R.*; 矢野 真一郎*; Chen, J.*; He, L.*; et al.
Materials Horizons, 10(3), p.977 - 982, 2023/03
被引用回数:34 パーセンタイル:89.62(Chemistry, Multidisciplinary)現在の蒸気圧縮式冷凍機に代わる環境に優しい冷凍機として、バロカロリック効果に基づく固体冷凍機が世界的に注目されている。一般に、バロカロリック効果が発現する相はいずれも常圧でも存在する。ここでは、それらの物質と違って、KPF
が高圧の菱面体晶相を生成することにより、巨大なバロカロリック効果を示すことを実証した。相図は、圧力依存の熱量測定、ラマン散乱測定、中性子回折測定に基づいて構築されたものである。本研究は、巨大バロカロリー効果に、高圧相の生成という新たな手法をもたらすと期待される。
Wei, D.*; Gong, W.; 都留 智仁; Lobzenko, I.; Li, X.*; Harjo, S.; 川崎 卓郎; Do, H.-S.*; Bae, J. W.*; Wagner, C.*; et al.
International Journal of Plasticity, 159, p.103443_1 - 103443_18, 2022/12
被引用回数:155 パーセンタイル:99.82(Engineering, Mechanical)Face-centered cubic single-phase high-entropy alloys (HEAs) containing multi-principal transition metals have attracted significant attention, exhibiting an unprecedented combination of strength and ductility owing to their low stacking fault energy (SFE) and large misfit parameter that creates severe local lattice distortion. Increasing both strength and ductility further is challenging. In the present study, we demonstrate via meticulous experiments that the CoCrFeNi HEA with the addition of the substitutional metalloid Si can retain a single-phase FCC structure while its yield strength (up to 65%), ultimate strength (up to 34%), and ductility (up to 15%) are simultaneously increased, owing to a synthetical effect of the enhanced solid solution strengthening and a reduced SFE. The dislocation behaviors and plastic deformation mechanisms were tuned by the addition of Si, which improves the strain hardening and tensile ductility. The present study provides new strategies for enhancing HEA performance by targeted metalloid additions.
La
Fe
Ni
As
Xie, T.*; Liu, C.*; 梶本 亮一; 池内 和彦*; Li, S.*; Luo, H.*
Journal of Physics; Condensed Matter, 34(47), p.474001_1 - 474001_8, 2022/11
被引用回数:0 パーセンタイル:0.00(Physics, Condensed Matter)We report time-of-flight inelastic neutron scattering (INS) investigations on the spin fluctuation spectrum in the 112-type iron-based superconductor (FeSC) Ca
La
Fe
Ni
As
(CaLa-112). In comparison to the 122-type FeSCs with a centrosymmetric tetragonal lattice structure (space group
) at room temperature and an in-plane stripe-type antiferromagnetic (AF) order at low temperature, the 112 system has a noncentrosymmetric structure (space group
) with additional zigzag arsenic chains between Ca/La layers and a magnetic ground state with similar wavevector
but different orientations of ordered moments in the parent compounds. Our INS study clearly reveals that the in-plane dispersions and the bandwidth of spin excitations in the superconducting CaLa-112 closely resemble to those in 122 systems. While the total fluctuating moments
/Fe are larger than 122 system, the dynamic correlation lengths are similar (
). These results suggest that superconductivity in iron arsenides may have a common magnetic origin under similar magnetic exchange couplings with a dual nature from local moments and itinerant electrons, despite their different magnetic patterns and lattice symmetries.
Xia, C.-J.*; 丸山 敏毅; Li, A.*; Sun, B. Y.*; Long, W.-H.*; Zhang, Y.-X.*
Communications in Theoretical Physics, 74(9), p.095303_1 - 095303_15, 2022/08
被引用回数:38 パーセンタイル:91.48(Physics, Multidisciplinary)In the framework of the Thomas-Fermi approximation, we study the EOSs and microscopic structures of neutron star matter in a vast density range with
-
, where various covarriant density functionals are adopted, i.e., those with nonlinear self couplings (NL3, PK1, TM1, GM1,MTVTC) and density-dependent couprings (DD-LZ1, DDME-X, PKDD, DD-ME2, DD2, TW99)It is found that the EOSs generally coincide with each other at
fm
and
fm
fm
, while in other density regions they are sensitive to the effective interactions between nucleons. By adopting functionals with a larger slope of symmetry energy
the curvature parameter
and neutron drip density generally increases, while the droplet size, proton number of nucleus, core-crust transition density and onset density of non-spherical nuclei, decrease. All functionals predict neutron stars, with maximum masses exceeding the two-solar-mass limit, while those of DD2, DD-LZ2, DD-ME2, and DDME-X predict optimum neutron star radii according to the observational constraints. Nevertheless, the corresponding skewness coefficients
are much larger than expected, while only the functionals MTVTC and TW99 meet the start-of-art constraints on
. More accurate measurements on the radius of PSR J0740+6620 and the maximum mass of neutron stars are thus essential to identify the functional that satisfies all constraints from nuclear physics and astrophysical observations. Approximate linear correlations between neutron stars' radii at
and
, the slope
and curvature parameter
of symmetry energy are adopted here. The results presented here are applicable for investigations of the structures and evolutions of compact stars in a unified manner.
PbZhang, W. Q.*; Andreyev, A. N.; Liu, Z.*; Seweryniak, D.*; Huang, H.*; Li, Z. H.*; Li, J. G.*; Guo, C. Y.*; 他34名*
Physics Letters B, 829, p.137129_1 - 137129_7, 2022/06
被引用回数:8 パーセンタイル:65.35(Astronomy & Astrophysics)Prompt and delayed
-ray spectroscopy of the neutron-deficient, semi-magic isotope
Pb has been performed at the Argonne Gas-Filled Analyzer. A new 5.15(15)-
s isomeric state at only 308 keV above the spherical 3/2
ground state is identified and classified as a shape isomer. A strongly-coupled band is observed on top of the isomer, which is nearly identical to the one built on the prolate 7/2
[514] Nilsson state in the isotone
Hg. Based on this similarity and on the result of the potential-energy surface calculations, the new isomer in
Pb is proposed to originate from the same configuration. The retarded character of the 308-keV transition can be well explained by the significant difference between the prolate parent and spherical daughter configurations, leading to the shape isomerism. The combined results of the present work and the previous
-decay and laser spectroscopy studies present evidence for triple shape coexistence at low energy in the negative-parity configurations of
Pb, which is well reproduced by the potential-energy surface calculations.