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論文

Assessing and tackling the barocaloric fatigue for applicable solid-state refrigeration

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

https://doi.org/10.1063/5.0333322
 被引用回数：0

NH$$_4$$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($$Delta T_{mathrm{ad}}$$)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$$_4$$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$$Delta T_{mathrm{ad}}$$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。

論文

$$3mathbf{Q}$$ magnetic order with spatially alternating spin scalar chirality in overdoped Co$$_{0.336}$$TaS$$_{2}$$

Cho, W.*; Park, P.*; Kim, C.*; An, Y.*; 飯田 一樹*; 梶本 亮一; Matin, S.*; Sibille, R.*; Crooker, S. A.*; Park, J.-G.*

Physical Review B, 113(17), p.174410_1 - 174410_14, 2026/05

https://doi.org/10.1103/d2yy-ntns
 被引用回数：0

Co$$_{x}$$TaS$$_{2}$$ ($$x approx 1/3$$) exhibits a spontaneous Hall effect from spin texture in antiferromagnets, with a tetrahedral triple-Q ($$3mathbf{Q}$$) order and uniform spin scalar chirality. Upon Co overdoping ($$x > 1/3$$), it undergoes a shift in magnetic ordering vectors from $$mathbf{Q}_mathrm{m} = (1/2, 0, 0)$$ to $$(1/3, 0, 0)$$. Interestingly, the spontaneous Hall effect disappeared in the overdoped regime, which was originally attributed to the loss of $$3mathbf{Q}$$ order. However, a question remains whether a new type of $$3mathbf{Q}$$ order can exist with alternating chirality in the overdoped regime. To address this, we investigated Co$$_{0.336}$$TaS$$_{2}$$ using inelastic neutron scattering (INS), neutron diffraction, and optical dichroism, and found that INS data and spin-wave simulations support a $$3mathbf{Q}$$ order with alternating chirality. Moreover, neutron diffraction data show field-independent Bragg peaks, while linear dichroism detects no in-plane anisotropy, consistent with threefold rotation symmetry. Our data support the scenario of an alternating-chirality $$3mathbf{Q}$$ order in Co$$_{0.336}$$TaS$$_{2}$$, cancelling the spontaneous Hall effect. This study highlights a combined neutron-optical approach to identify complex spin textures.

論文

Magnetization process of the layered diluted ferromagnetic semiconductor (Ba,K)(Zn,Mn)$$_2$$As$$_2$$ studied by X-ray magnetic circular dichroism

Wan, Y.*; 芝田 悟朗; 竹田 幸治*; 岡根 哲夫; 斎藤 祐児; 山上 浩志; 藤森 淳*; 他10名*

Physical Review Materials (Internet), 10(5), p.054402_1 - 054402_8, 2026/05

https://doi.org/10.1103/69sm-fz7z
 被引用回数：0

In order to unveil the nature of the ferromagnetism in (Ba,K)(Zn,Mn)$$_2$$As$$_2$$, its magnetization process has been studied by X-ray magnetic circular dichroism (XMCD) at the Mn $$L_{2,3}$$ edge in a wide range of temperature and magnetic field. The average magnetization of the Mn atoms as a function of magnetic field ($$M$$-$$H$$ curves) at various temperatures could be successfully explained by a mixture of paramagnetic (PM), superparamagnetic (SPM), and ferromagnetic (FM) components as previously reported for GaMnAs, revealing the complex nature of the ferromagnetism in (Ba,K)(Zn,Mn)$$_2$$As$$_2$$. The average magnetization of the SPM clusters of different sizes and the FM regions were found to be small compared to those in GaMnAs, which we attribute to the antiferromagnetic interaction between nearest-neighbor Mn atoms in (Ba,K)(Zn,Mn)$$_2$$As$$_2$$ on the basis of recent theoretical predictions.

論文

Intercomparison of low-energy electron transport calculations by different Monte Carlo track-structure simulation codes

Kyriakou, I.*; Papadopoulos, A.*; Polopetrakis, I.*; Kotroumbelou, C.*; Plante, I.*; 松谷 悠佑; 甲斐 健師; Qiu, R.*; Li, J.*; Kundr$'a$t, P.*; et al.

Physics in Medicine & Biology, 71(8), p.085009_1 - 085009_25, 2026/04

https://doi.org/10.1088/1361-6560/ae5758
 被引用回数：0

過去40年間にわたり、液体の水を対象としたモンテカルロ飛跡構造(MCTS)コードが世界中で数多く開発されてきたが、相互作用断面積は大きく異なる。本研究では、6種類の異なるMCTSコードの使用による、液相水中の低エネルギー電子輸送の物理的特性(電子阻止能、経路長、dose-point-kernel、微視的線量付与)の不確実性を評価することを目指した。コード間比較の結果により、特に100eV以下の低エネルギー領域において、MCTSコード間で大きな差異があることが明らかになり、電子線が重要な役割を果たすDNA損傷シミュレーションの精度に影響を与えることが示された。本研究は、液相水中の低エネルギー電子輸送計算に伴う不確実性を低減するために、MCTSコードで使用される物理モデルの更なる開発の必要性を浮き彫りにしている。

論文

Magnetic signature of chiral phonons revealed by neutron spectroscopy in ferrimagnetic Fe$$_{1.75}$$Zn$$_{0.25}$$Mo$$_{3}$$O$$_{8}$$

Bao, S.*; Liao, J.*; Huang, Z.*; Shangguan, Y.*; Ma, Z.*; Zhang, B.*; Cheng, S.*; Xu, H.*; Song, Z.*; Dong, S.*; et al.

Physical Review Letters, 136(9), p.096502_1 - 096502_8, 2026/03

https://doi.org/10.1103/pq5m-32wj
 被引用回数：1 パーセンタイル：0.00(Physics, Multidisciplinary)

Lattice vibrations can carry angular momentum and magnetic moments under broken inversion or time-reversal symmetry, forming so-called chiral phonons. While such excitations have been explored in nonmagnetic systems via optical probes, their direct detection in magnetic materials and coupling to spin excitations remain largely unexplored. Here, using neutron spectroscopy, sensitive to both nuclear and magnetic scattering, we reveal the magnetic signature of chiral phonons in ferrimagnetic Fe$$_{1.75}$$Zn$$_{0.25}$$Mo$$_{3}$$O$$_{8}$$ with Curie temperature $$T_C sim 49$$ K. Below $$T_C$$, we observe enhanced magnetic scattering of phonons at small momenta, arising from strong magnon-phonon coupling. In addition, out-of-plane intensity modulation, phonon mode splitting, and field-induced Zeeman shifts are observed, all closely associated with the ferrimagnetic order. These features vanish above $$T_C$$, where phonon spectra are dominated by nuclear scattering. These observations demonstrate the existence of chiral phonons carrying substantial magnetic moments that directly contribute to magnetic scattering, and establish neutron spectroscopy as a powerful, momentum-resolved probe of their magnetic character.

論文

Magnetic evolution, phase transitions, and electronic band structure of the ferrotoroidic candidate Ba$$_6$$Cr$$_2$$S$$_{10}$$

Zhao, G.*; Li, J.*; Zhang, J.*; 小嶋 健児*; Cai, Y.*; 伊藤 孝; Yoon, S. W.*; Wang, X.*; 前川 禎通*; Su, G.*; et al.

Physical Review Research (Internet), 8(1), p.013331_1 - 013331_10, 2026/03

https://doi.org/10.1103/h576-nnnz

Ferrotoroidic materials, which break both time- and space-reversal symmetries to enhance magnetoelectric responses, are of great interest for applications. Ba$$_6$$Cr$$_2$$S$$_{10}$$, a recently synthesized quasi-one-dimensional ferrotoroidic candidate, combines polarization, magnetization, and toroidal moment, yet its electronic band structure, magnetic evolution, and phase transitions remain incompletely understood to date. Here, we investigate Ba$$_6$$Cr$$_2$$S$$_{10}$$, using electrical transport, direct current magnetization, alternating current susceptibility, specific heat, and muon spin rotation ($$mu$$SR) measurements, along with various first-principles calculations. Electrical transport measurements and density functional theory confirm a narrow band gap ($$sim$$0.707~eV, experimentally; $$sim$$0.680~eV, theoretically). $$mu$$SR measurements reveal that static magnetism dominates down to 2~K, with an ordered volume fraction of $$sim$$89% at this temperature. Two distinct transitions are identified: one around the N$'{e}$el temperature [$$T_{rm N}=(8pm 1)$$~K] and another corresponding to a phase transition near 30~K, as consistently indicated by our complementary experimental techniques. The absence of dynamic critical behaviors and the lack of a $$lambda$$-type specific heat anomaly are consistent with a first-order-like transition at $$T_{rm N}$$. Based on various complementary experimental results and theoretical calculations, we propose a hypothesis that the $$sim$$30~K broad feature arises from the complex interplay between crystal structure distortion and magnetic coupling, which is potentially directly linked to ferrotoroidicity. As the first study integrating $$mu$$SR with complementary experiments and first-principles calculations to explore ferrotoroidicity, this work provides key insights into the underlying physics of Ba$$_6$$Cr$$_2$$S$$_{10}$$ and related compounds in this area.

論文

Coupled dimerized alternating-bond quantum spin chains in the distorted honeycomb-lattice magnet Cu$$_{5}$$SbO$$_{6}$$

Piyakulworawat, C.*; 森田 克洋*; 福元 好志*; Hsieh, W.-Y.*; Chen, W.-T.*; 中島 健次; 河村 聖子; Zhao, Y.*; Wannapaiboon, S.*; Piyawongwatthana, P.; et al.

Physical Review Research (Internet), 8(1), p.013247_1 - 013247_16, 2026/03

https://doi.org/10.1103/vdgg-d128

歪んだハニカム化合物Cu$$_{5}$$SbO$$_{6}$$の中性子非弾性散乱および磁化データを、一次のダイマー展開計算と量子モンテカルロシミュレーションを用いて解析した。これまでに提案されたハニカム格子モデルとは対照的に、この系は相互作用するダイマースピン鎖を有し、鎖に沿って強磁性-反強磁性結合が交互に現れることが示された。さらに、他のCu$$^{2+}$$ベースの歪んだハニカム磁性体で観測される典型的な結合とは異なり、スピン鎖は、予想される層間の鎖間結合ではなく、主にハニカム層間に生じる反強磁性結合を介して結合する。つまり、Cu$$_{5}$$SbO$$_{6}$$の磁気結合スキームが異なることが明らかになった。さらに、X線分光法と透過型電子顕微鏡を利用して、化合物の結晶構造と積層欠陥モデルも従来のモデルをより精密化した。

論文

Low-temperature deformation mechanism in a work-hardenable body-centered cubic high-entropy alloy with a large uniform elongation

Zhu, L.*; Dong, W.*; Naeem, M.*; Kong, H.*; Hu, C.*; Fan, Z.*; Gong, W.; Harjo, S.; Lan, S.*; Wu, Y.*; et al.

Acta Materialia, 303, p.121734_1 - 121734_10, 2026/01

https://doi.org/10.1016/j.actamat.2025.121734
 被引用回数：3 パーセンタイル：35.08(Materials Science, Multidisciplinary)

Body-centered cubic (BCC) metals typically exhibit high yield strength but limited work hardening and uniform elongation, especially at low temperatures. High-entropy alloys (HEAs) offer opportunities to overcome these limitations, though their deformation mechanisms remain unclear. Using in situ neutron diffraction and microstructural analysis, this study identifies the origin of the exceptionally large uniform elongation at liquid nitrogen temperature in a single-phase BCC (TiZrHf)$$_{86.4}$$Al$$_2$$Nb$$_{11.6}$$ HEA. Initial plastic deformation is governed by a BCC-to-orthorhombic ($$alpha$$") transformation, followed by $$alpha$$" twinning and deformation-induced amorphization at later stages. The cooperation of these mechanisms suppresses work softening from dislocation plasticity, enabling high yield strength with large uniform elongation and providing a viable strategy for designing cryogenic structural materials.

論文

Microscopic insights into the mechanical behavior of a Ni-Co-based superalloy through ${it in-situ}$ neutron diffraction

Liu, Y.*; Yan, Z.*; Gao, Y.*; Li, Y.*; Gan, B.*; Harjo, S.; Gong, W.; 川崎 卓郎; Li, S.*; Wang, Y.-D.*

Microstructures (Internet), 5(4), p.2025096_1 - 2025096_15, 2025/10

https://doi.org/10.20517/microstructures.2025.28

The micromechanical behaviors and dislocation evolution in a polycrystalline Ni-Co-based superalloy were systematically investigated by ${it in situ}$ neutron diffraction tensile testing combined with line profile analysis. The results reveal the sequential activation of $$gamma$$' shearing and Orowan looping mechanisms, with interphase load partitioning governed by strain-dependent interactions of dislocation and precipitate. During the initial plastic deformation, the $$gamma$$ and $$gamma$$' phases undergo co-deformation through dislocation shearing without load transfer, while the Orowan looping facilitates the load transfer from $$gamma$$ to $$gamma$$' phase at a higher strain level. Furthermore, the low stacking fault energy leads to a rising fraction of screw dislocations by suppressing cross-slip. Crucially, the pinning effect of $$gamma$$' precipitates hinders the rearrangement of these dislocations into low-energy structures, resulting in the formation of high-energy, weakly screened dislocation configurations. These findings provide new evidence for the planar slip dominance in Ni-Co-based superalloys, enabling quantitative assessment of microstructural evolution and micromechanical responses.

論文

Pressure-driven solid-state radical polymerization toward carbon nanothread

Che, G.*; Tang, X.*; Liu, J.*; Lang, P.*; Fei, Y.*; Yang, X.*; Wang, Y.*; Gao, D.*; Wang, X.*; Ju, J.*; et al.

Nano Letters, 25(39), p.14467 - 14472, 2025/09

https://doi.org/10.1021/acs.nanolett.5c03977
 被引用回数：1 パーセンタイル：0.00(Chemistry, Multidisciplinary)

機械化学的ラジカル重合は、溶媒消費量の削減と不溶性モノマーへの適応性により、ポリマー合成において独自の利点を有する。しかしながら、反応中に生成ポリマーが制御不能に分解するという課題があり、精密な制御性を備えた新たな合成戦略の開発が求められている。本研究では、最大30GPaの高静圧を適用することで、1,3,5-トリフルオロベンゼンが共役$$pi$$結合を切断するラジカル重合を起こし、高選択性でカーボンナノスレッド(ポリマーI多形体)を形成することを発見した。閾値圧力における結晶構造と結合経路の計算エネルギー障壁に基づき、ベンゼン環が1-2ラジカル重合経路で反応すると結論付けた。本研究は、極めて安定な芳香族化合物に対しても固相ラジカル重合を開始する堅牢な手法として高圧が有効であることを示し、高選択性を持つ炭素系高分子材料の合成に向けた新たな知見を提供する。

論文

Strengthening characteristics of CoCrNi alloys with different stacking fault energies

Peng, S. Y.*; Gong, W.; Tian, Y. Z.*; Harjo, S.; 他5名*

International Journal of Plasticity, 191, p.104401_1 - 104401_15, 2025/08

https://doi.org/10.1016/j.ijplas.2025.104401
 被引用回数：18 パーセンタイル：98.11(Engineering, Mechanical)

Quantifying the contributions of various strengthening mechanisms is essential for manipulating these mechanisms and designing novel alloys. Although CoCrNi alloys demonstrate exceptional mechanical properties, their strengthening characteristics remain to be investigated. In this work, we conducted in situ neutron diffraction tensile tests and characterized deformation microstructures for CoCrNi alloys with different stacking fault energies (SFEs). The dislocation strengthening characteristics and the role of planar faults were systematically investigated. A reduction in SFE restricts cross slip, thereby increasing the dislocation multiplication rate while decreasing the dislocation strengthening coefficient $$alpha$$. Additionally, a lower SFE facilitates the simultaneous activation of dislocations and planar faults, with dislocation strengthening consistently playing a dominant role. This work quantifies reasonable $$alpha$$ values for CoCrNi alloys and identifies cross slip as a critical factor potentially influencing $$alpha$$ value in face-centered cubic (FCC) alloys.

論文

All-temperature barocaloric effects at pressure-induced phase transitions

Zhao, X.*; Zhang, Z.*; 服部 高典; Wang, J.*; Li, L.*; Jia, Y.*; Li, W.*; Xue, J.*; Fan, X.*; Song, R.*; et al.

Nature Communications (Internet), 16, p.7713_1 - 7713_8, 2025/08

https://doi.org/10.1038/s41467-025-63068-z
 被引用回数：6 パーセンタイル：80.06(Multidisciplinary Sciences)

熱効果は、固体状態の冷凍技術の一つの解決策の基盤を成すもので、通常は固体状態の相転移付近で発生し、冷凍温度範囲が限定されている。ここでは、前例のない概念である「全温度帯バロカロリック効果」を導入し実現する。すなわち、KPF$$_6$$において77.5Kから300Kの極めて広い温度範囲(潜在的に4Kまで)で観測される顕著なバカカロリック効果である。この温度範囲は、一般的な室温、液体窒素、液体水素、液体ヘリウムの冷却領域をカバーしている。直接測定されたバーカロリック断熱温度変化は、250MPaの圧力を解放した際に、室温で12K、77.5Kで2.5Kに達する。この効果は、圧力依存性の中性子粉末回折、ラマン散乱解析、第一原理計算により示されるように、菱面体高圧相への持続的な相転移に起因する。構造的不安定性を考慮した熱力学的エネルギーランドスケープを記述する。この独自の全温度帯バロカロリック効果は、従来の多段式シナリオを超えた、高度に適用可能な固体状態冷凍技術への新たなアプローチを提供する。

論文

Electrical coherent driving of chiral antiferromagnet

竹内 祐太朗*; 佐藤 佑磨*; 山根 結太*; Yoon, J.-Y.*; 菅野 之矩*; 内村 友宏*; De Zoysa, K. V.*; Han, J.*; 金井 駿*; 家田 淳一; et al.

Science, 389(6762), p.830 - 834, 2025/08

https://doi.org/10.1126/science.ado1611
 被引用回数：10 パーセンタイル：89.98(Multidisciplinary Sciences)

Electric current driving of antiferromagnetic states at radio or higher frequencies remains challenging to achieve. In this study, we report all-electrical, gigahertz-range coherent driving of chiral antiferromagnet manganese-tin (Mn$$_{3}$$Sn) nanodot samples. High coherence in multiple trials and threshold current insensitive to pulse width, in contrast to results observed with ferromagnets, were achieved in subnanosecond range, allowing 1000/1000 switching by 0.1-nanosecond pulses at zero field. These features are attributed to the inertial nature of antiferromagnetic excitations. Our study highlights the potential of antiferromagnetic spintronics to combine high speed and high efficiency in magnetic device operations.

論文

Spin dynamics of triple-$$mathbf{Q}$$ magnetic orderings in a triangular lattice; Implications for multi-$$mathbf{Q}$$ orderings in general two-dimensional lattices

Park, P.*; Cho, W.*; Kim, C.*; An, Y.*; 飯田 一樹*; 梶本 亮一; Matin, S.*; Zhang, S.-S.*; Batista, C. D.*; Park, J.-G.*

Physical Review X, 15(3), p.031032_1 - 031032_29, 2025/07

https://doi.org/10.1103/y9ly-4kld
 被引用回数：3 パーセンタイル：66.10(Physics, Multidisciplinary)

Multi-$$mathbf{Q}$$ magnetic structures on two-dimensional (2D) lattices provide a key route to realizing topological physics in 2D magnetism. A major experimental challenge is to unambiguously confirm their formation by excluding the possibility of topologically trivial multi-domain single- or double-$$mathbf{Q}$$ magnetic orders, which cannot be distinguished using conventional diffraction techniques. Here, we propose that long-wavelength spin dynamics offers a universal diagnostic for triangular lattices: triple-$$mathbf{Q}$$ orders that preserve rotational symmetry and single- or double-$$mathbf{Q}$$ orders that break it exhibit qualitatively distinct anisotropies in their Goldstone mode velocities, stemming from fundamental differences in their underlying spin configurations. We validate this concept using the metallic triangular-lattice antiferromagnet Co$$_{0.325}$$TaS$$_{2}$$, which hosts both a stripe-type single-$$mathbf{Q}$$ state and a triple-$$mathbf{Q}$$ tetrahedral ordering at different temperatures. Using inelastic neutron-scattering and spin dynamics simulations, we first refine the spin Hamiltonian by fitting the paramagnetic excitation spectra, allowing us to develop an unbiased model independent of magnetic ordering. We then show that the observed velocity profiles of the Goldstone modes agree with the high-temperature model's predictions: markedly anisotropic for the single-$$mathbf{Q}$$ phase and near isotropic for the triple-$$mathbf{Q}$$ phase. Importantly, this contrast persists across various exchange parameters, highlighting its model-independent nature and suggesting potential applicability to other 2D lattice systems. Beyond the long-wavelength regime, we present a substantial discrepancy between the measured and simulated magnon spectra exclusively in the triple-$$mathbf{Q}$$ phase. We attribute this discrepancy to magnon energy renormalization arising from order-of-magnitude-enhanced magnon-magnon interactions in the triple-$$mathbf{Q}$$ phase, due to its noncollinear configuration. This work provides universal insight into the dynamical properties of topological multi-$$mathbf{Q}$$ magnetic orderings in 2D lattice structures, offering a broadly applicable diagnostic to distinguishing them from topologically trivial single- or double-$$mathbf{Q}$$ counterparts. The unequivocal confirmation of the triple-$$mathbf{Q}$$ structure in Co$$_{0.325}$$TaS$$_{2}$$ further establishes it as a prominent material platform for exploring topological spin textures in the genuine 2D limit.

論文

Numerical simulation of coupled THM behaviour of full-scale EBS in backfilled experimental gallery in the Horonobe URL

杉田 裕; 大野 宏和; Beese, S.*; Pan, P.*; Kim, M.*; Lee, C.*; Jove-Colon, C.*; Lopez, C. M.*; Liang, S.-Y.*

Geomechanics for Energy and the Environment, 42, p.100668_1 - 100668_21, 2025/06

https://doi.org/10.1016/j.gete.2025.100668
 被引用回数：5 パーセンタイル：76.00(Energy & Fuels)

国際共同プロジェクトDECOVALEX-2023は、数値解析を使用してベントナイト系人工バリアの熱-水-応力(または熱-水)相互作用を研究するためのタスクDとして、幌延人工バリア性能確認試験を対象とした。このタスクは、モデル化のために、1つの実物大の原位置試験と、補完的な4つの室内試験が選択された。幌延人工バリア性能確認試験は、人工的な地下水注入と組み合わせた温度制御非等温の試験であり、加熱フェーズと冷却フェーズで構成されている。6つの研究チームが、さまざまなコンピューターコード、定式化、構成法則を使用して、熱-水-応力または熱-水(研究チームのアプローチによって異なる)数値解析を実行した。

論文

Effect of a repulsive three-body interaction on the $$DD^{(*)}K$$ molecule

Pan, Y.-W.*; Lu, J.-X.*; 肥山 詠美子*; Geng, L.-S.*; 保坂 淳

Physical Review D, 111(11), p.114006_1 - 114006_9, 2025/06

https://doi.org/10.1103/jk8x-qv2p
 被引用回数：2 パーセンタイル：38.00(Astronomy & Astrophysics)

ガウス展開法を使った三体計算によって$$DD^{(*)}K$$分子に対する斥力三体力の影響を調べた結果を報告する。

論文

Synthesis of BaSiH$$_6$$ hydridosilicate at high pressures; A Bridge to BaSiH$$_8$$ polyhydride

Beyer, D. C.*; Spektor, K.*; Vekilova, O. Y.*; Grins, J.*; Barros Brant Carvalho, P. H.*; Leinbach, L. J.*; Sannemo-Targama, M.*; Bhat, S.*; Baran, V.*; Etter, M.*; et al.

ACS Omega (Internet), 10(15), p.15029 - 15035, 2025/04

https://doi.org/10.1021/acsomega.4c10502
 被引用回数：2 パーセンタイル：52.89(Chemistry, Multidisciplinary)

SiH$$_6$$八面体部位を特徴とするヒドリドケイ酸塩は、水素貯蔵と水素化物イオン伝導に関連する潜在的な性質を持つかなり新しい化合物のクラスである。ここでは、Zintl相水素化物BaSiH$$_{sim 1.8}$$を4GPa以上の圧力でH$$_2$$流体と反応させ、その後常圧まで減圧して得られた新しい代表的なBaSiH$$_6$$について報告する。SiH$$_{6}^{2-}$$イオンはBa$$^{2+}$$対イオンによって八面体に配位している。Ba原子とSi原子の配置は理想的なfcc NaCl構造からわずかにずれている。IRとラマンスペクトルからSiH$$_{6}^{2-}$$の屈曲と伸縮モードがそれぞれ800-1200と1400-1800cm$$^{-1}$$の範囲で観測された。BaSiH$$_6$$は95$$^circ$$Cまで熱的に安定であり、それ以上ではBaH$$_2$$とSiに分解する。DFT計算により、直接バンドギャップは2.5eVであることが示された。BaSiH$$_6$$の発見により、ギガパスカル圧力(10GPa以下)のシリサイドの水素化反応からアクセス可能なヒドリドケイ酸塩の化合物クラスが固まった。BaSiH$$_6$$の構造的性質は、超伝導ポリハイドライドBaSiH$$_8$$を予測されるより高い圧力で水素化するための中間体(あるいは前駆体)であることを示唆している。

論文

Incorporation of boron into metakaolin-based geopolymers for radionuclide immobilisation and neutron capture potential

Niu, X.*; Elakneswaran, Y.*; Li, A.*; Seralathan, S.*; 菊池 亮佑*; 平木 義久; 佐藤 淳也; 大杉 武史; Walkley, B.*

Cement and Concrete Research, 190, p.107814_1 - 107814_17, 2025/04

https://doi.org/10.1016/j.cemconres.2025.107814
 被引用回数：10 パーセンタイル：92.34(Construction & Building Technology)

Metakaolin-based geopolymers have attracted significant interest in decontaminating radioactive debris from the Fukushima nuclear accident. This study explored the incorporation of boron (B) into geopolymers using boric acid as the source, with the goal of developing B-enriched geopolymers for enhanced radionuclide immobilisation and neutron capture potential.

論文

Uncertainty quantification for severe-accident reactor modelling; Results and conclusions of the MUSA reactor applications work package

Brumm, S.*; Gabrielli, F.*; Sanchez Espinoza, V.*; Stakhanova, A.*; Groudev, P.*; Petrova, P.*; Vryashkova, P.*; Ou, P.*; Zhang, W.*; Malkhasyan, A.*; et al.

Annals of Nuclear Energy, 211, p.110962_1 - 110962_16, 2025/02

https://doi.org/10.1016/j.anucene.2024.110962
 被引用回数：15 パーセンタイル：96.17(Nuclear Science & Technology)

The completed Horizon-2020 project on "Management and Uncertainties of Severe Accidents (MUSA)" has reviewed uncertainty sources and Uncertainty Quantification methodology for the purpose of assessing Severe Accidents (SA). The key motivation of the project has been to bring the advantages of the Best Estimate Plus Uncertainty approach to the field of Severe Accident. The applications brought together a large group of participants that set out to apply uncertainty analysis (UA) within their field of SA modelling expertise, in particular reactor types, but also SA code used (ASTEC, MELCOR, etc.), uncertainty quantification tools used (DAKOTA, RAVEN, etc.), detailed accident scenarios, and in some cases SAM actions. This paper synthesizes the reactor-application work at the end of the project. Analyses of 23 partners are sorted into different categories, depending on whether their main goal is/are (i) uncertainty bands of simulation results; (ii) the understanding of dominating uncertainties in specific sub-models of the SA code; (iii) improving the understanding of specific accident scenarios, with or without the application of SAM actions; or, (iv) a demonstration of the tools used and developed, and of the capability to carry out an uncertainty analysis in the presence of the challenges faced. The partners' experiences made during the project have been evaluated and are presented as good practice recommendations. The paper ends with conclusions on the level of readiness of UA in SA modelling, on the determination of governing uncertainties, and on the analysis of SAM actions.

論文

Unusual low-temperature ductility increase mediated by dislocations alone

Naeem, M.*; Ma, Y.*; Tian, J.*; Kong, H.*; Romero-Resendiz, L.*; Fan, Z.*; Jiang, F.*; Gong, W.; Harjo, S.; Wu, Z.*; et al.

Materials Science & Engineering A, 924, p.147819_1 - 147819_10, 2025/02

https://doi.org/10.1016/j.msea.2025.147819
 被引用回数：7 パーセンタイル：87.47(Nanoscience & Nanotechnology)

Face-centered cubic (fcc) medium-/high-entropy alloys (M/HEAs) typically enhance strength and ductility at cryogenic temperatures via stacking faults, twinning, or martensitic transformation. However, in-situ neutron diffraction on VCoNi MEA at 15 K reveals that strain hardening is driven solely by rapid dislocation accumulation, without these mechanisms. This results in increased yield strength, strain hardening, and fracture strain. The behavior, explained by the Orowan equation, challenges conventional views on cryogenic strengthening in fcc M/HEAs and highlights the role of dislocation-mediated plasticity at low temperatures.

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