JAEA
  • help
  • PC | SP
  • JP | EN
          
検索対象：     
報告書番号：
※ 半角英数字
 年 ～ 
 年
全てクリア
検索結果：　460 件中 1件目～20件目を表示

発表形式

Initialising ...

選択項目を絞り込む

掲載資料名

Initialising ...

発表会議名

Initialising ...

筆頭著者名

Initialising ...

キーワード

Initialising ...

使用言語

Initialising ...

発行年

Initialising ...

開催年

Initialising ...

選択した検索結果をダウンロード

論文

A Systematic approach for the adequacy analysis of a set of experimental databases: Application in the framework of the ATRIUM activity

Baccou, J.*; Glantz, T.*; Ghione, A.*; Sargentini, L.*; Fillion, P.*; Damblin, G.*; Sueur, R.*; Iooss, B.*; Fang, J.*; Liu, J.*; et al.

Nuclear Engineering and Design, 421, p.113035_1 - 113035_16, 2024/05

https://doi.org/10.1016/j.nucengdes.2024.113035

In the Best-Estimate Plus Uncertainty (BEPU) framework, the use of best-estimate code requires to go through a Verification, Validation and Uncertainty Quantification process (VVUQ). The relevance of the experimental data in relation to the physical phenomena of interest in the VVUQ process is crucial. Adequacy analysis of selected experimental databases addresses this problem. The outcomes of the analysis can be used to select a subset of relevant experimental data, to encourage designing new experiments or to drop some experiments from a database because of their substantial lack of adequacy. The development of a specific transparent and reproducible approach to analyze the relevance of experimental data for VVUQ still remains open and is the topic of this contribution. In this paper, the concept of adequacy initially introduced in the OECD/NEA SAPIUM (Systematic APproach for model Input Uncertainty quantification Methodology) activity is formalized. It is defined through two key properties, called representativeness and completeness, that allows considering the multifactorial dimension of the adequacy problem. A new systematic approach is then proposed to analyze the adequacy of a set of experimental databases. It relies on the introduction of two sets of criteria to characterize representativeness and completeness and on the use of multi-criteria decision analysis method to perform the analysis. Finally, the approach is applied in the framework of the new OECD/NEA ATRIUM activity which includes a set of practical IUQ exercises in thermal-hydraulics to test the SAPIUM guideline in determining input uncertainties and forward propagating them on an application case. It allows evaluating the adequacy of eight experimental databases coming from the Super Moby-dick, Sozzi-Sutherland and Marviken experiments and identifying the most adequate ones.

論文

The BCC $$rightarrow$$ FCC hierarchical martensite transformation under dynamic impact in FeMnAlNiTi alloy

Li, C.*; Fang, W.*; Yu, H. Y.*; Peng, T.*; Yao, Z. T.*; Liu, W. G.*; Zhang, X.*; 徐 平光; Yin, F.*

Materials Science & Engineering A, 892, p.146096_1 - 146096_11, 2024/02

https://doi.org/10.1016/j.msea.2024.146096
 被引用回数：0 パーセンタイル：0.04(Nanoscience & Nanotechnology)

The quasi-static superelastic responses and hierarchical martensite transformation from body-centered cubic (BCC) to face-centered cubic (FCC) under dynamic impact in Fe$$_{42}$$Mn$$_{34}$$Al$$_{15}$$Ni$$_{7.5}$$Ti$$_{1.5}$$ alloys were investigated. Polycrystalline and oligocrystalline alloys were produced through solution heat treatment and cyclic heat treatment processes, respectively. The results show the volume fraction of residual martensite for oligocrystalline alloys is lower, which exhibits better superelastic responses compared with polycrystalline alloys. Dynamic impact tests indicate that, despite the weakening of the grain boundary strengthening effect, the ultimate strength of the oligocrystalline alloys closely matches that of the polycrystalline alloys under dynamic impact. The martensite transformation of the FeMnAlNiTi alloy is characterized as hierarchical under dynamic impact, and increasing strain rates and grain sizes can enhance the BCC $$rightarrow$$ FCC martensite transformation, resulting in higher martensite phase fractions for oligocrystalline alloys. The increase in ultimate strength is attributed to the dynamic Hall-Petch effect introduced by more martensite phase interfaces under dynamic impact.

論文

Gradient residual strain measurement procedure in surface impacted railway steel axles by using neutron scattering

Zhou, L.*; Zhang, H.*; Qin, T. Y.*; Hu, F. F.*; 徐 平光; Ao, N.*; Su, Y. H.; He, L. H.*; Li, X. H.*; Zhang, J. R.*; et al.

Metallurgical and Materials Transactions A, 11 Pages, 2024/00

https://doi.org/10.1007/s11661-024-07352-5
 被引用回数：0

High-speed railway S38C axles undergo surface induction hardening for durability, but are susceptible to fatigue cracks from foreign object impact. The neutron diffraction method was employed to measure the residual strain in S38C axles, obtaining microscopic lattice distortion data, for the gradient layer at a depth of 8 mm under the surface. The results showed that after induction-hardening, the microscopic lattice distortion had a gradient distribution, decreasing with the distance from the surface. However, in the case of impacting speed of 600 km/m, the average microscopic lattice distortion increased with the distance from the surface, reaching a maximum augmentation of 55 pct. These findings indicate a strong experimental basis, and improve our understanding of the relationship between macroscopic residual stress and decision-making, in regard to operation and maintenance.

論文

Electromagnetic moments of the antimony isotopes $$^{112-133}$$Sb

Lechner, S.*; 宮城 宇志*; Xu, Z. Y.*; Bissell, M. L.*; Blaum, K.*; Cheal, B.*; Devlin, C. S.*; Garcia Ruiz, R. F.*; Ginges, J. S. M.*; Heylen, H.*; et al.

Physics Letters B, 847, p.138278_1 - 138278_9, 2023/12

https://doi.org/10.1016/j.physletb.2023.138278
 被引用回数：0 パーセンタイル：0.02(Astronomy & Astrophysics)

不安定核を含むアンチモン同位体$$^{112-133}$$Sbの磁気モーメントと電気的四重極モーメントをレーザー分光を用いて測定した。現象論的な相互作用と有効演算子を用いた殻模型計算によって測定値をよく再現することができた。第一原理に基づいたVS-IMSRG法による殻模型計算では、磁気モーメントは現象論的な有効演算子を用いればよく実験値を再現するものの、電気的四重極モーメントについては有効電荷を用いても現象論的な相互作用を用いた計算ほどには実験値を再現することができなかった。

論文

Field-tuned quantum renormalization of spin dynamics in the honeycomb lattice Heisenberg antiferromagnet YbCl$$_3$$

Sala, G.*; Stone, M. B.*; Hal$'a$sz, G. B.*; Lumsden, M. D.*; Fay, A, F,*; Pajerowski, D. M.*; 河村 聖子; 金子 耕士; Mazzone, D. G.*; Simutis, G.*; et al.

Communications Physics (Internet), 6, p.234_1 - 234_7, 2023/08

https://doi.org/10.1038/s42005-023-01333-7
 被引用回数：0 パーセンタイル：0(Physics, Multidisciplinary)

We demonstrate and elucidate quantum effects on the honeycomb lattice through comprehensive inelastic neutron scattering measurements of the prototype honeycomb lattice quantum magnet YbCl$$_{3}$$ as a function of applied magnetic field. Examining the spectrum above the saturation field where linear spin-wave theory is essentially exact, we accurately determine the dominant nearest-neighbor Heisenberg interaction. Below the saturation field, we reveal a field-dependent energy renormalization of the entire magnetic spectrum; the sharp spin-wave modes as well as the multimagnon continuum. This renormalization is a quantum effect that can be accurately captured by the first 1=S correction in nonlinear spin-wave theory. Furthermore, we find that the application of a magnetic field induces a qualitatively new sharp feature inside the multimagnon continuum; the lower edge of a specific two-magnon component; which is complementary to the previously observed Van Hove singularity and demonstrates that structures within the multimagnon continuum can occur over a wide experimental parameter space and can be used as an additional means of identifying quantum phenomena.

論文

Level structures of $$^{56,58}$$Ca cast doubt on a doubly magic $$^{60}$$Ca

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

https://doi.org/10.1016/j.physletb.2023.138025
 被引用回数：1 パーセンタイル：0.02(Astronomy & Astrophysics)

$$^{57,59}$$Scからの1陽子ノックアウト反応を用いて、$$^{56}$$Caと$$^{58}$$Caのガンマ崩壊を観測した。$$^{56}$$Caでは1456(12)keVの$$gamma$$線遷移が、$$^{58}$$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$$2^{+}_{1} rightarrow 0^{+}_{gs}$$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、$$2^{+}_{1}$$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$$0_{f5/2}$$と$$0_{g9/2}$$軌道はほぼ縮退しており、これは$$^{60}$$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$$^{70}$$Caあるいはそれ以上にまで広げる可能性がある。

論文

Nuclear structure in parity doublet model

Mun, M.-H.*; Shin, I. J.*; Paeng, W.-G.*; 原田 正康*; Kim, Y.*

European Physical Journal A, 59(7), p.149_1 - 149_6, 2023/07

https://doi.org/10.1140/epja/s10050-023-01064-x
 被引用回数：0 パーセンタイル：0.02(Physics, Nuclear)

Using an extended parity doublet model with the hidden local symmetry, we study some properties of nuclei in the mean field approximation to see if the parity doublet model could reproduce nuclear properties and also to estimate the value of the chiral invariant nucleon mass $$m$$$$_{0}$$ preferred by nuclear structure. We first determine our model parameters using the inputs from free space and from nuclear matter properties. Then, we study some basic nuclear properties such as the nuclear binding energy with several different choices of the chiral invariant mass. We observe that our results approach the experimental values as $$m$$$$_{0}$$ is increased until $$m$$$$_{0}$$= 700 MeV and start to deviate more from the experiments afterwards with m0 larger than $$m$$$$_{0}$$ = 700 MeV. From this observation, we conclude that $$m$$$$_{0}$$ = 700 MeV is preferred by nuclear properties. We then calculate some properties of several selected nuclei with $$m$$$$_{0}$$ = 700 MeV and compare them with experiments. Finally, we study the neutron-proton mass difference in some nuclei.

論文

Extreme phonon anharmonicity underpins superionic diffusion and ultralow thermal conductivity in argyrodite Ag$$_{8}$$SnSe$$_{6}$$

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, p.999 - 1006, 2023/05

https://doi.org/10.1038/s41563-023-01560-x
 被引用回数：21 パーセンタイル：99.22(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$$_{8}$$SnSe$$_{6}$$ 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$$^{-1}$$K$$^{-1}$$) and fast diffusion. Our results provide fundamental insights into the complex atomic dynamics in superionic materials for energy conversion and storage.

論文

Pressure-modulated magnetism and negative thermal expansion in the Ho$$_2$$Fe$$_{17}$$ intermetallic compound

Cao, 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

https://doi.org/10.1021/acs.chemmater.3c00158
 被引用回数：1 パーセンタイル：0(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$$_2$$Fe$$_{17}$$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。

論文

Multiple mechanisms in proton-induced nucleon removal at $$sim$$100 MeV/nucleon

Pohl, T.*; Sun, Y. L.*; Obertelli, A.*; Lee, J.*; G$'o$mez-Ramos, M.*; 緒方 一介*; 吉田 数貴; Cai, B. S.*; Yuan, C. X.*; Brown, B. A.*; et al.

Physical Review Letters, 130(17), p.172501_1 - 172501_8, 2023/04

https://doi.org/10.1103/PhysRevLett.130.172501
 被引用回数：5 パーセンタイル：92.42(Physics, Multidisciplinary)

大きなフェルミ面非対称性を持つ陽子過剰な$$^{14}$$O原子核からの100MeV/nucleonでの陽子による陽子・中性子除去反応について報告した。この結果は、quasi-freeノックアウト反応、非弾性散乱、核子移行反応を含む複数の反応機構の定量的寄与を初めて示すものである。このようなエネルギー領域では通常無視される非弾性散乱と核子移行の寄与が、弱束縛陽子と強束縛中性子の除去反応断面積にそれぞれ約50%と30%寄与していることが示された。

論文

Full-$$f$$ gyrokinetic simulations of ohmic L-mode plasmas in linear and saturated ohmic confinement regimes

井戸村 泰宏; Dif-Pradalier, G.*; Garbet, X.*; Sarazin, Y.*; Tore Supra Teams*

Physics of Plasmas, 30(4), p.042508_1 - 042508_18, 2023/04

https://doi.org/10.1063/5.0127346
 被引用回数：1 パーセンタイル：56.19(Physics, Fluids & Plasmas)

非線形大域的full-$$f$$ジャイロ運動論シミュレーションを用いて、Tore Supra装置のジュール加熱Lモード放電における線形/飽和オーミック閉じ込め(LOC/SOC)領域の2時刻を解析した。トロイダルフィールド応力による早いイオン混合が炭素不純物の吐き出しを引き起こす。LOC/SOCフェーズで自発プラズマ回転が逆方向に発展し、これはLOCフェーズの捕捉電子モードとSOCフェーズのイオン温度勾配駆動モードにおけるモード非対称性の違いがもたらす分布シア応力の変化によって決まる。LOC/SOCフェーズにおいて電子と重水素イオンのエネルギー束がそれぞれ支配的になる。この2つのフェーズにおけるエネルギー閉じ込め時間の比率について実験値を再現した。

論文

Flow filtration/adsorption and simultaneous monitoring technologies of radiocesium $$^{137}$$Cs in river water

榎本 一之*; 保科 宏行*; 笠井 昇*; 栗田 圭輔; 植木 悠二*; 長尾 悠人*; 尹 永根*; 鈴井 伸郎*; 河地 有木*; 瀬古 典明*

Chemical Engineering Journal, 460, p.141696_1 - 141696_9, 2023/03

https://doi.org/10.1016/j.cej.2023.141696
 被引用回数：1 パーセンタイル：49.6(Engineering, Environmental)

本研究では、モリブドリン酸アンモニウム(AMP)を放射線グラフト重合した繊維状のCs吸着フィルターとCe:Gd$$_3$$Al$$_2$$Ga$$_3$$O$$_{12}$$シンチレータを用いた$$gamma$$線検出器を組み合わせて、連続水流中の$$^{137}$$Csの放射能濃度をその場で測定する方法を開発した。

論文

Tensile overload-induced texture effects on the fatigue resistance of a CoCrFeMnNi high-entropy alloy

Lam, T.-N.*; Chin, H.-H.*; Zhang, X.*; Feng, R.*; Wang, H.*; Chiang, C.-Y.*; Lee, S. Y.*; 川崎 卓郎; Harjo, S.; Liaw, P. K.*; et al.

Acta Materialia, 245, p.118585_1 - 118585_9, 2023/02

https://doi.org/10.1016/j.actamat.2022.118585
 被引用回数：8 パーセンタイル：80.32(Materials Science, Multidisciplinary)

The present study investigates the crystallographic-texture effects on the improved fatigue resistance in the CoCrFeMnNi high-entropy alloys (HEAs) with the full-size geometry of the ASTM Standards E647-99. We exploited X-ray nano-diffraction mapping to characterize the crystal-deformation levels ahead of the crack tip after stress unloading under both constant- and tensile overloaded-fatigue conditions. The crack-tip blunting-induced much higher deformation level was concentrated surrounding the crack-tip which delays the fatigue-crack growth immediately after a tensile overload. The predominant deformation texture orientation in the Paris regime was investigated, using electron backscatter diffraction and orientation distribution function analyses. The twinning formation-driven shear deformation gave rise to the development of the Goss-type texture within the plastic deformation regime under a tensile-overloaded-fatigue condition, which was attributed to enhance the crack deflection and thus the tensile induced crack-growth-retardation period in the CoCrFeMnNi HEA.

論文

"Southwestern" boundary of the $$N = 40$$ island of inversion; First study of low-lying bound excited states in $$^{59}$$V and $$^{61}$$V

Elekes, Z.*; Juh$'a$sz, M. M.*; Sohler, D.*; Sieja, K.*; 吉田 数貴; 緒方 一介*; Doornenbal, P.*; Obertelli, A.*; Achouri, N. L.*; 馬場 秀忠*; et al.

Physical Review C, 106(6), p.064321_1 - 064321_10, 2022/12

https://doi.org/10.1103/PhysRevC.106.064321
 被引用回数：2 パーセンタイル：0.02(Physics, Nuclear)

$$^{59}$$Vと$$^{61}$$Vの低励起準位構造を初めて探索した。$$^{61}$$Vについては中性子ノックアウト反応と陽子非弾性散乱が、$$^{59}$$Vについては中性子ノックアウト反応データが得られた。$$^{59}$$Vについては4つ、$$^{61}$$Vについては5つの新たな遷移が確認された。Lenzi-Nowacki-Poves-Sieja (LNPS)相互作用に基づく殻模型計算との比較によって、それぞれの同位体について確認されたガンマ線のうち3つが、first 11/2$$^{-}$$状態とfirst 9/2$$^{-}$$状態からの崩壊と決定された。$$^{61}$$Vについては、($$p$$,$$p'$$)非弾性散乱断面積は四重極変形と十六重極変形を想定したチャネル結合法により解析されたが、十六重極変形の影響により、明確に反転の島に属するとは決定できなかった。

論文

Extended $$p_{3/2}$$ neutron orbital and the $$N = 32$$ shell closure in $$^{52}$$Ca

Enciu, M.*; Liu, H. N.*; Obertelli, A.*; Doornenbal, P.*; Nowacki, F.*; 緒方 一介*; Poves, A.*; 吉田 数貴; Achouri, N. L.*; 馬場 秀忠*; et al.

Physical Review Letters, 129(26), p.262501_1 - 262501_7, 2022/12

https://doi.org/10.1103/PhysRevLett.129.262501
 被引用回数：4 パーセンタイル：46.35(Physics, Multidisciplinary)

$$sim$$230MeV/nucleonでの$$^{52}$$Caからの中性子ノックアウト反応が$$gamma$$線分光と行われ、$$1f_{7/2}$$と$$2p_{3/2}$$軌道からの中性子ノックアウト反応の運動量分布が測定された。断面積は$$N=32$$の閉殻と整合し、Ca同位体での$$N=28$$と$$N=34$$閉殻と同程度に強い閉殻であることが確認された。運動量分布の分析から$$1_{f7/2}$$と$$2p_{3/2}$$軌道の平均二乗根半径の差は0.61(23)fmと決定され、これはmodified-shell-modelによる予言の0.7fmと整合した。これは、中性子過剰なCa同位体での$$2p_{3/2}$$軌道半径が大きいことが、中性子数にしたがって線形的に荷電半径が増える意外な現象の原因であることを示唆している。

論文

Experimental and analytical investigations on aerosol washout in a large vessel with high spray coverage ratio simulating PWR containment spray

孫 昊旻; Leblois, Y.*; Gelain, T.*; Porcheron, E.*

Journal of Nuclear Science and Technology, 59(11), p.1356 - 1369, 2022/11

https://doi.org/10.1080/00223131.2022.2055673
 被引用回数：0 パーセンタイル：0.01(Nuclear Science & Technology)

PWRのシビアアクシデントシナリオにおいて、格納容器内エアロゾル状放射性物質の除去・保持のために、格納容器スプレイを用いることができる。そのために、高精度な除去効率の予測は安全評価上重要である。PWRの格納容器スプレイでは、84%-95%と高いスプレイカバー率が要求されるのに対して、既往研究では、そのような高いカバー率におけるエアロゾル除去実験はかなり限られている。本論文では、カバー率に着目し、スプレイによるエアロゾル除去現象の理解と除去効率評価モデル高度化のために、大型容器において実機相当のカバー率を有する体系のエアロゾル除去実験を実施し、詳細なエアロゾルと液滴特性の計測結果から除去特性を調査した。また、MELCORの除去モデルと実験結果を比較し、粒子径に対する除去効率の傾向が再現でき、大きい粒子径に対して過小評価となるものの、最小除去効率を有する小さい粒子径($$<$$0.52$$mu$$m)において良好な一致が得られることを示した。

論文

Estimating fine melt pool, coarse melt pool, and heat affected zone effects on the strengths of additive manufactured AlSi10Mg alloys

Lam, T.-N.*; Lee, A.*; Chiu, Y.-R.*; Kuo, H.-F.*; 川崎 卓郎; Harjo, S.; Jain, J.*; Lee, S. Y.*; Huang, E.-W.*

Materials Science & Engineering A, 856, p.143961_1 - 143961_9, 2022/10

https://doi.org/10.1016/j.msea.2022.143961
 被引用回数：4 パーセンタイル：45.58(Nanoscience & Nanotechnology)

Fine melt pool (FMP), coarse melt pool (CMP), and heat affected zone (HAZ) are generally observed in the additive manufactured AlSi10Mg alloys. In this study, we demonstrated that the yield strength can be estimated by the combination of the sizes and volume fractions of FMP, CMP, HAZ together with the second-phase hardening. Two different AlSi10Mg alloys fabricated via powder bed fusion (PBF) process were prepared to examine the lattice strain evolution of constituent phases during uniaxial tensile loading via in-situ neutron diffraction measurements. The horizontally-built (Hz-built) exhibited a much better yield and tensile strength as well as elongation compared to the vertically-built (Vt-built) AlSi10Mg alloy. We reported empirical strength quantification based on the sizes and ratios of fine melt pool (FMP), coarse melt pool (CMP), and heat affected zone (HAZ) together with the possible failure mode to prevent early fracture in the additive manufactured alloys.

論文

Two-step Mott transition in Ni(S,Se)$$_2$$; $$mu$$SR studies and charge-spin percolation model

Sheng, Q.*; 金子 竜也*; Yamakawa, Kohtaro*; Guguchia, Z.*; Gong, Z.*; Zhao, G.*; Dai, G.*; Jin, C.*; Guo, S.*; Fu, L.*; et al.

Physical Review Research (Internet), 4(3), p.033172_1 - 033172_14, 2022/09

https://doi.org/10.1103/PhysRevResearch.4.033172

A pyrite system NiS$$_{2-x}$$Se$$_x$$ exhibits a bandwidth controlled Mott transition via (S,Se) substitutions in a two-step process: the antiferromagnetic insulator (AFI) to antiferromagnetic metal (AFM) transition at $$xsim$$0.45 followed by the AFM to paramagnetic metal (PMM) transition at $$xsim$$1.0. Among a few other Mott systems which exhibit similar two-step transitions, Ni(S,Se)$$_2$$ is of particular interest because a large intermediate AFM region in the phase diagram would provide unique opportunities to study the interplay between the spin and charge order. By comparing and combining our muon spin relaxation studies and previous neutron scattering studies, here we propose a picture where the spin order is maintained by the percolation of "nonmetallic" localized and dangling Ni moments surrounded by S, while the charge transition from AFI to AFM is caused by the percolation of the conducting paths generated by the Ni-Se-Ni bonds.

論文

State-of-the-art of WPS in RPV PTS analysis

Zarazovski, M.*; Pistra, V.*; Lauerova, D.*; Obermeier, F.*; Mora, D.*; Dubyk, Y.*; Bolinder, T.*; Cueto-Felgueroso, C.*; Szavai, S.*; Dudra, J.*; et al.

Proceedings of ASME 2022 Pressure Vessels and Piping Conference (PVP 2022) (Internet), 11 Pages, 2022/07

The APAL (Advanced Pressurized Thermal Shock (PTS) Analysis for Long-Term Operation (LTO)) project was launched in October 2020 for four years with funding from the European Union's HORIZON 2020 program. Within APAL, an extensive literature review was performed and experience with defining the state-of-the-art of the Warm Pre-Stress (WPS) effect, which has an impact on the reactor pressure vessel (RPV) brittle fracture margin in both deterministic and probabilistic terms, was collected. To gather the worldwide experience of the WPS approaches and models, a comprehensive questionnaire was developed followed by each APAL partner response. It mainly focused on the following aspects: collection of existing WPS approaches and models implemented in standards and rules for RPV brittle fracture assessment; identification of the WPS issues; collection and analysis of the existing experimental data. This work describes worldwide experience and best practice of the WPS and its application for the RPV integrity assessment. The paper's conclusions are also focused on the recommendations for dealing with WPS issues.

論文

Magnetic properties and electronic configurations of Mn ions in the diluted magnetic semiconductor Ba$$_{1-x}$$K$$_x$$(Zn$$_{1-y}$$Mn$$_y$$)$$_2$$As$$_2$$ studied by X-ray magnetic circular dichroism and resonant inelastic X-ray scattering

鈴木 博人*; Zhao, G.*; 岡本 淳*; 坂本 祥哉*; Chen, Z.-Y.*; 野中 洋亮*; 芝田 悟朗; Zhao, K.*; Chen, B.*; Wu, W.-B.*; et al.

Journal of the Physical Society of Japan, 91(6), p.064710_1 - 064710_5, 2022/06

https://doi.org/10.7566/JPSJ.91.064710
 被引用回数：0 パーセンタイル：0(Physics, Multidisciplinary)

The magnetic properties and the electronic excitations of the new diluted magnetic semiconductor Ba$$_{1-x}$$K$$_x$$(Zn$$_{1-y}$$Mn$$_y$$)$$_2$$As$$_2$$ have been studied by X-ray magnetic circular dichroism (XMCD) and resonant inelastic X-ray scattering (RIXS). The sum rule analysis of the XMCD spectra indicates that the Mn atoms are in the high-spin configurations of $$d^5$$, whereas the presence of competing ferromagnetic and antiferromagnetic interactions between the Mn ions reduces the net spin moment. Based on a comparison of the RIXS line shapes with those of Ga$$_{1-x}$$Mn$$_x$$As, it is concluded that the ground state of Mn in Ba$$_{1-x}$$K$$_x$$(Zn$$_{1-y}$$Mn$$_y$$)$$_2$$As$$_2$$ consists of both the $$3d^5 underline{L}$$ and $$3d^5$$ electron configurations.

460 件中 1件目～20件目を表示