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N(
,
)
O reaction rates via the 
F(,
)
F reactionKim, S. H.*; Chae, K. Y.*; 浅井 雅人; 廣瀬 健太郎; 佐藤 哲也; 牧井 宏之; 西尾 勝久; Orlandi, R.; Smallcombe, J.; 洲嵜 ふみ; et al.
Journal of the Korean Physical Society, 89(5), p.488 - 493, 2026/09
被引用回数：0 パーセンタイル：0.00(Physics, Multidisciplinary)コア崩壊超新星爆発(CCSNe)の元素合成シミュレーションにおいて、N(,)O反応速度の不確実性が課題となっていた。本研究では、この反応を制約するため、JAEAタンデム加速器でF(,)F遷移反応実験を実施した。得られたトリトンスペクトルと角度分布から、関連するF共鳴の崩壊特性(部分幅)を詳細に測定し、その結果を用いて反応速度パラメータを精密化した。これにより、CCSNe核合成モデルの信頼性向上が期待できる。
Ha, H.*; Kim, J.*; Gu, G. H.*; Harjo, S.; Gong, W.; Hong, S.-J.*; Kim, H. S.*
Materials Characterization, 234, p.116086_1 - 116086_12, 2026/04
被引用回数：2 パーセンタイル：94.05(Materials Science, Multidisciplinary)Dual-phase (DP) high- and medium-entropy alloys (H/MEAs), consisting of face-centered cubic (FCC) and body-centered cubic (BCC) phases, have attracted attention because of their excellent strength-ductility balance. However, the temperature dependence of hetero-deformation-induced (HDI) strengthening remains unclear. In this study, an Al
(CoNiV)
DP MEA was investigated using in-situ neutron diffraction and multiscale electron microscopy. Both intrinsic strength and HDI strengthening increased at cryogenic temperature. This enhancement originated from the increased lattice friction stress of the hard BCC phase and suppressed dislocation mobility at low temperature, which promoted dislocation accumulation at heterogeneous interfaces. These findings provide insights into temperature-dependent HDI strengthening in DP H/MEAs and related alloy systems.
Ahn, S. Y.*; Kim, E. S.*; Jeong, S. G.*; Harjo, S.; 川崎 卓郎; Gong, W.; Kim, H.-J.*; Hong, S.-J.*; Hong, S. I.*; Kwon, H.*; et al.
Materials Science & Engineering A, 955, p.149839_1 - 149839_18, 2026/03
被引用回数：3 パーセンタイル：91.05(Nanoscience & Nanotechnology)Additive manufacturing (AM) of particle-reinforced metal matrix composites (MMCs) enables control of both strength and deformation behavior. In this study, TiC (2 wt%) nanoparticles were added to Fe
Co
NiCr
medium-entropy alloy (MEA) using directed energy deposition (DED). Although part of the TiC decomposed during processing, the released C and Ti stabilized the 
-austenite phase and suppressed deformation-induced martensitic transformation (DIMT), shifting deformation toward slip-dominated behavior. Microstructural observations revealed dispersed TiC particles and modified grain boundary morphology that promoted distributed plastic flow. In-situ neutron diffraction during tensile testing confirmed enhanced early-stage dislocation activity. These findings demonstrate that nanoparticle-induced phase stability changes strongly influence deformation mechanisms in AM-processed MMCs.
Gu, G. H.*; Jeong, S. G.*; Lee, J. H.*; Harjo, S.; Gong, W.; Amanov, A.*; Bae, J. W.*; Kwon, H.*; Kim, H. S.*
International Journal of Plasticity, 197, p.104581_1 - 104581_21, 2026/02
被引用回数：9 パーセンタイル：81.63(Engineering, Mechanical)Stacking fault energy (SFE) controls key deformation mechanisms in metals. This study demonstrates that apparent SFE and deformation behavior can be tuned by modifying only the near-surface microstructure (
100 um) through surface severe plastic deformation. The resulting gradient microstructure reduces apparent SFE, promoting martensitic transformation via preferential nucleation and stress partitioning. Consequently, mechanical properties are enhanced, achieving higher strength with minimal ductility loss, highlighting the effectiveness of localized microstructural engineering.
Jeong, S. G.*; Kwon, J.*; Kim, E. S.*; Prasad, K.*; Harjo, S.; Gong, W.; 川崎 卓郎; Estrin, Y.*; Bouaziz, O.*; Hong, S. I.*; et al.
Materials Science & Engineering A, 942, p.148712_1 - 148712_11, 2025/10
被引用回数：3 パーセンタイル：41.88(Nanoscience & Nanotechnology)The cellular structure plays a key role in determining the mechanical properties of metal additive manufacturing (MAM) components. This study presents in situ neutron diffraction and dislocation density-based modeling for a CoCrFeMnNi high-entropy alloy (HEA) made via directed energy deposition (DED). A constitutive model based on the Kocks-Mecking-Estrin framework was used to represent the cellular structure. Parametric analysis showed lower dislocation accumulation and annihilation rates in the as-built sample (with cellular structure) than in the heat-treated one. These differences are linked to dislocation forest networks and local stacking fault energy variations. Dislocation density across cell interiors and walls was also compared with deformation-induced dislocation cells.
Gu, G. H.*; Ha, H.*; Harjo, S.; Gong, W.; Louzguine-Luzgin, D. V.*; Kim, H. S.*
Materials Science & Engineering A, 943, p.148818_1 - 148818_10, 2025/10
被引用回数：4 パーセンタイル：56.20(Nanoscience & Nanotechnology)High-strength structural alloys are essential for advanced engineering. This study explores the mechanical behavior of a dual-phase AlCoNiV medium-entropy alloy (MEA) with FCC and BCC phases. The alloy shows excellent performance, with a yield strength of 1148 MPa, tensile strength of 1556 MPa, and 40% uniform elongation. In-situ neutron diffraction and EBSD analyses reveal that strength originates from the intrinsic responses of both phases. The BCC phase carries more load, while dislocation buildup at phase boundaries enhances strength via hetero-deformation-induced (HDI) strengthening. Synergistic effects, including stress partitioning and load redistribution, further improve mechanical performance. These findings highlight the role of phase-specific properties and interphase interactions in alloy robustness and offer insights for microstructural optimization.
ders band-assisted high uniform ductility in ultrastrong ferrous medium-entropy alloy via hierarchical microstructureKwon, H.*; Lee, J. H.*; Zargaran, A.*; Harjo, S.; Gong, W.; Wang, J.*; Gu, G. H.*; Lee, B.-J.*; Bae, J. W.*; Kim, H. S.*
International Journal of Plasticity, 190, p.104378_1 - 104378_18, 2025/07
被引用回数：17 パーセンタイル：95.86(Engineering, Mechanical)In this work, we harness a hierarchical microstructure to simultaneously tailor strengthening and deformation mechanisms in a Co
Cr
Fe
Ni
Mo
(at%) ferrous medium-entropy alloy (MEA). A simple thermomechanical process (cold rolling and 90 s annealing) produces ultrafine recrystallized grains, non-recrystallized grains with substructures, and intragranular nanoprecipitates. This structure, with high dislocation density and fine grains, yields a high strength of 1.60 GPa but can risk premature fracture. To overcome this, Lders deformation, enabled by ultrafine grain boundaries and stress-induced martensitic transformation at pre-existing nucleation sites, is employed. Stable Lders band propagation delays strain hardening and enables large uniform ductility. As a result, a tensile strength of 1.84 GPa and uniform elongation of 20% are achieved, matching the best tensile properties among reported multi-principal element alloys.
Gu, G. H.*; Jeong, S. G.*; Heo, Y.-U.*; Harjo, S.; Gong, W.; Cho, J.*; Kim, H. S.*; 他4名*
Journal of Materials Science & Technology, 223, p.308 - 324, 2025/07
被引用回数：9 パーセンタイル：89.01(Materials Science, Multidisciplinary)Face-centered cubic (FCC) equi-atomic multi-principal element alloys (MPEAs) exhibit excellent mechanical properties from cryogenic to room temperatures. At room temperature, deformation is dominated by dislocation slip, while at cryogenic temperatures (CTs), reduced stacking fault energy enhances strain hardening with twinning. This study uses in-situ neutron diffraction to analyze the temperature-dependent deformation behavior of Al(CoNiV), a dual-phase (FCC/BCC) medium-entropy alloy (MEA). At liquid nitrogen temperature (LNT), deformation twinning in the FCC matrix leads to additional strain hardening through the dynamic Hall-Petch effect, giving the appearance of improved strengthening at LNT. In contrast, BCC precipitates show dislocation slip at both 77 K and 298 K, with temperature-dependent lattice friction stress playing a significant role in strengthening. The study enhances understanding of deformation behaviors and provides insights for future alloy design.
Kim, Y. S.*; Kang, T.*; Hong, S.-K.*; Brechtl, J.*; Lebyodkin, M.*; Cheng, Y.-H.*; Huang, E.-W.*; Liaw, P. K.*; Harjo, S.; Gong, W.; et al.
Acta Materialia, 292, p.120970_1 - 120970_16, 2025/06
被引用回数：16 パーセンタイル：96.07(Materials Science, Multidisciplinary)Metallic materials can exhibit low-temperature serrated deformation (LTSD) at cryogenic temperatures, potentially causing sudden failures. Understanding LTSD is thus crucial for ensuring material reliability in such environments. LTSD has been explained by two main mechanisms: (i) dislocation-based mechanical instability and (ii) thermomechanical instability, but each has limitations when considered alone. To address this, we propose a new LTSD mechanism, a thermally induced dislocation dynamics model, based on cryogenic experimental evidence. This model accounts for dislocation avalanches and localized heating, leading to hierarchical dislocation networks and transitions in deformation modes. A modified deformation-mechanism map for SS316L is also presented. Our findings highlight the rate-dependent nature of LTSD and negative strain-rate sensitivity, including the first observation of links between small stress fluctuations and large serrations.
Cho, S. H.*; Cho, S. W.*; Lv, Z.*; 関根 由莉奈; Liu, S.*; Zhou, M.*; Nuxoll, R. F.*; Kanatzidis, E. E.*; Ghaffari, R.*; Kim, D.*; et al.
Lab on a Chip, 25(7), p.1647 - 1655, 2025/04
被引用回数：16 パーセンタイル：98.63(Biochemical Research Methods)アミノ酸は体内のタンパク質合成と代謝プロセスに不可欠な物質である。本研究では、運動中の汗からのアミノ酸損失について定量的に調べることを目的とした。汗中のアミノ酸含有量をリアルタイムで分析するため、測定のための技術基盤としてウェアラブルなマイクロ流体システムを構築した。定量分析を実現するため、ウェアラブルデバイスに蛍光アッセイを組み込み、さらにスマートフォンベースの画像化技術を統合させたシステムを開発した。
Chung, J.-H.*; Kwangwoo, S.*; Yokoo, Tetsuya R.; 植田 大地*; 今井 正樹; Kim, H.-S.; Kiem, D. H.; Han, M. J.*; 社本 真一
Scientific Reports (Internet), 15, p.5978_1 - 5978_10, 2025/02
被引用回数：2 パーセンタイル：55.25(Multidisciplinary Sciences)Two dimensional honeycomb ferromagnets host massless Dirac magnons which are a bosonic analogue of Dirac fermions in graphene. The Dirac magnons may become massive and topological when the time-reversal symmetry breaks and an energy gap opens up at the Dirac point, which was experimentally observed in Cr
-based van der Waals magnets. Here, we investigate the spin wave excitations in the 
magnetic oxide FeTiO with Fe
electrons (
). Using inelastic neutron scattering, we observe two magnon bands separated by a 1.2-meV gap at the Dirac points indicating that its Dirac magnons are massive. Using the linear spin-wave and density functional theory calculations, we find that the spin-orbit-coupled antisymmetric Dzyaloshinskii-Moriya exchanges can best account for the observed Dirac gap opening. The associated Berry curvature and Chern number (
) indicate that FeTiO hosts topological spin excitations via time-reversal symmetry breaking of Dirac magnons.
signatures in two-dimensional cone beam interferometrySarenac, D.*; Gorbet, G.*; Clark, C. W.*; Cory, D. G.*; Ekinci, H.*; Henderson, M. E.*; Huber, M. G.*; Hussey, D. S.*; Kapahi, C.*; Kienzle, P. A.*; et al.
Physical Review Research (Internet), 6(3), p.L032054_1 - L032054_8, 2024/09
Neutron interferometry has played a distinctive role in fundamental science and characterization of materials. Moir neutron interferometers are candidate next-generation instruments: they offer microscopy-like magnification of the signal, enabling direct camera recording of interference patterns across the full neutron wavelength spectrum. Here we demonstrate the extension of phase-grating moir interferometry to two-dimensional geometries. Our measurements of phase topologies and gravitationally induced phase shifts are in good agreement with theory.
Khemchandani, K. P.*; Mart
nez Torres, A.*; Kim, S.-H.*; Nam, S.-I.*; 保坂 淳; 永廣 秀子*
EPJ Web of Conferences, 301, p.03001_1 - 03001_10, 2024/08
被引用回数：0 パーセンタイル：0.00(Physics, Nuclear)3個の軽いクォークからなるバリオン共鳴がバレンスクォーク模型で記述できない例について議論する。
Nguyen, T.-D.*; Singh, C.*; Kim, Y. S.*; Han, J. H.*; Lee, D.-H.*; Lee, K.*; Harjo, S.; Lee, S. Y.*
Journal of Materials Research and Technology, 31, p.1547 - 1556, 2024/07
被引用回数：10 パーセンタイル：66.69(Materials Science, Multidisciplinary)This study investigates the mechanical properties of a friction-stir-welded (FSW) AA6061-T6 aluminum alloy at ultra-low temperature (ULT) of 20 K. In-situ neutron diffraction and orientation imaging microscopy were employed to compare the tensile deformation behavior of the base metal (BM) and heat-affected zone (HAZ) in the FSW aluminum plate. The results demonstrate that compared to room-temperature (RT), ULT induces a significant improvement in tensile strength and ductility in both the BM and HAZ. The enhanced mechanical properties in BM at ULT result from a more homogeneous deformation than occurs at RT. On the other hand, HAZ at ULT exhibits an even lower yield strength than at RT, but the strain hardening rate (SHR) is the most significant among the alloys, leading to a tensile strength of 346 MPa and the highest ductility of 46.8%. The lowest yield strength corresponds to the lowest-hardness zones in HAZ, caused by dissolved/coarsened precipitates during the FSW process.
久保田 真彦*; Kim, S.-Y.*; Wu, H.*; 渡部 創; 佐野 雄一; 竹内 正行; 新井 剛*
Journal of Radioanalytical and Nuclear Chemistry, 333(5), p.2413 - 2420, 2024/05
被引用回数：5 パーセンタイル：62.23(Chemistry, Analytical)To minimize the use of organic solvents and achieve a selective adsorption separation of minor actinides (MA(III)) and Ln(III), adsorbents consisting of SiO
-P particles impregnated with hexaoctylnitrilotriacetamide (HONTA) were prepared. Batch experiments were performed to evaluate the adsorption properties of the HONTA/SiO-P adsorbent for MA(III) and simulated fission products in HNO
solution. The uniform distribution of Eu(III) on the adsorbent was confirmed via particle induced X-ray emission analysis, and X-ray photoelectron spectroscopy revealed that EuNO was the adsorbed species. This study provides a simplified process for the separation of MA(III) using a HONTA/SiO-P packed column.
Kim, Y. S.*; Chae, H.*; Lee, D.-Y.*; Han, J. H.*; Hong, S.-K.*; Na, Y. S.*; Harjo, S.; 川崎 卓郎; Woo, W.*; Lee, S.-Y.*
Materials Science & Engineering A, 899, p.146453_1 - 146453_7, 2024/05
被引用回数：13 パーセンタイル：76.83(Nanoscience & Nanotechnology)This work focused on the mechanical properties and serration-involved deformation behavior of advanced alloys at 15 K. Evolution of stacking faults and 
-martensite improved the mechanical performance of CoCrNi alloys, and significant strain-induced martensite transformation of DED-SS316L led to superior strength and strain hardening. A magnitude in stress drop was governed by dislocation density, phase type, and lattice defects, irrespective of processing method. FCC {200} notably was influenced recovery behavior after stress drop, and the contribution of strain energy density by serration on tensile toughness was the greatest for HR-CoCrNi.
大沢 直樹*; Kim, S.-Y.*; 久保田 真彦*; Wu, H.*; 渡部 創; 伊藤 辰也; 永石 隆二
Nuclear Engineering and Technology, 56(3), p.812 - 818, 2024/03
被引用回数：7 パーセンタイル：71.07(Nuclear Science & Technology)An impregnated silica-based adsorbent was prepared by combining HONTA extractant, Crea extractant, and macroporous silica polymer composite particles (SiO-P). The performance of platinum-group metals adsorption and separation on prepared (HONTA + Crea)/SiO-P adsorbent was assessed by batch-adsorption and chromatographic separation studies. (HONTA + Crea)/SiO-P adsorbent showed high adsorption performance of Pd(II) owing to an affinity between Pd(II) and Crea extractant based on the Hard and Soft Acids and Bases theory. The chromatographic experiment showed that Pd(II) was recovered entirely from the feed solution using 0.2 M thiourea in 0.1 M HNO. Possibility of recovery of Zr(IV), Mo(VI), and Re(VII) was also observed using the (HONTA + Crea)/SiO-P adsorbent.
Linh, B. D.*; Corsi, A.*; Gillibert, A.*; Obertelli, A.*; Doornenbal, P.*; Barbieri, C.*; Duguet, T.*; G
mez-Ramos, M.*; Holt, J. D.*; Hu, B. S.*; et al.
Physical Review C, 109(3), p.034312_1 - 034312_15, 2024/03
被引用回数：6 パーセンタイル：76.58(Physics, Nuclear)理化学研究所RIビームファクトリーにて中性子過剰核
Arビームからの1中性子ノックアウト反応実験を行い、
Arのエネルギー準位および分光学的因子を導出した。特に、第一励起状態の
への分光学的因子が大きいことから、始状態のArの基底状態において中性子が
軌道を多く占めていることがわかった。これは、中性子数32がよい魔法数として知られる
Caとは異なった性質であり、カルシウムからアルゴンへと陽子が2個減ることで閉殻構造が大きく崩れることが明らかになった。
Kim, G.*; Cho, S.-M.*; Im, S.*; Suh, H.*; 諸岡 聡; 菖蒲 敬久; 兼松 学*; 町田 晃彦*; Bae, S.*
Construction and Building Materials, 411, p.134529_1 - 134529_18, 2024/01
被引用回数：19 パーセンタイル：73.55(Construction & Building Technology)This study explores the influence of the interatomic structure of sodium aluminosilicate hydrate (N-A-S-H) with varying silica contents on the mechanical properties of metakaolin-based geopolymer. Geopolymer pastes comprising Si/Al ratios between 2.0 and 3.0 were synthesized. A larger number of Si-O-Si linkages compared to Si-O-Al linkages and a higher atomic number density were found in the geopolymers with higher silica contents, which enhanced the compressive strength of the geopolymer pastes up to the optimal Si/Al ratio of 2.5. The paste with a Si/Al = 2.5 exhibited a greater portion of Q
(1Al and 2Al) and denser morphology compared to the other geopolymer pastes. Furthermore, in-situ high-energy synchrotron X-ray scattering experiments were conducted to assess the elastic modulus of the aluminosilicate structure at a local atomic scale. The modulus value in real space decreases with increasing silica contents up to Si/Al = 2.5 and increases with the presence of excessive unreacted silica fume. The modulus value in reciprocal space for the axial and lateral directions both presented a positive value at the geopolymer comprising a Si/Al ratio higher than 2.5, indicating that the load-bearing property of N-A-S-H changed at higher Si/Al ratios. Moreover, the smallest difference between the strains along the axial and lateral directions was detected for the geopolymer with Si/Al = 2.5 in both the real and reciprocal space, owing to the most interconnected and flexible nanostructure, which led to the highest mechanical strength.
Cho, S.*; Suh, H.*; Im, S.*; Kim, G.*; 兼松 学*; 諸岡 聡; 町田 晃彦*; 菖蒲 敬久; Bae, S.*
Construction and Building Materials, 409, p.133866_1 - 133866_20, 2023/12
被引用回数：24 パーセンタイル：77.29(Construction & Building Technology)The effects of various initial carbonation curing environments on the phase evolution and resulting mechanical characteristics of tricalcium silicate paste were studied. For the analyses of the reaction products and microstructure, synchrotron X-ray diffraction, thermogravimetry, Fourier transform-infrared spectroscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy and high-resolution X-ray computed tomography were utilized. CS cured under carbonation environment pressurized by 0.1 MPa showed excellent mechanical properties owing to the highest degree of reaction and homogeneous generation of CaCO with low-Ca/Si calcium silicate hydrates, resulting in a dense matrix with refined pore structure. CS paste treated under other carbonation conditions underwent deteriorative microstructural phase transitions, including void evolution by decalcification of C-S-H and an inhomogeneous composition of crystalline phases, resulting in inferior properties.
