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論文

Residual stress measurement and lifetime evaluation of railway axles by neutron scattering technology

Hu, F.-F.*; Qin, T.-Y.*; Ao, N.*; 徐平光; Su, Y. H.; Parker, J. D.*; 篠原武尚; 菖蒲敬久; Kang, G.-Z.*; Ren, M.-M.; et al.

Journal of Traffic and Transportation Engineering, 25(2), p.75 - 93, 2025/04

https://dx.doi.org/10.19818/j.cnki.1671-1637.2025.02.005

https://transport.chd.edu.cn/en/article/doi/10.19818/j.cnki.1671-1637.2025.02.005

https://transport.chd.edu.cn/cn/article/doi/10.19818/j.cnki.1671-1637.2025.02.005

To accurately predict the remaining lifetime of surface-strengthened railway axles, a damage tolerance method considering three-dimensional (3D) residual stresses was proposed. By taking the induction-hardened carbon steel S38C axle as an example, two-dimensional (2D) distribution characterization of residual strain and 3D residual stress measurement were performed through comprehensive application of the neutron Bragg-edge transmission imaging and angle-dispersive neutron diffraction experiments. A numerical method was employed to implant the 3D residual stress into the axle model, and the remaining lifetime of the full-scale axle was studied by coupling the measured load spectrum, press-fit loads, and residual stresses. Experimental results shows that, both axial and hoop directions present a compressive residual strain gradient layer of about 3 mm, with a maximum compressive residual strain of up to -4500 in the surface layer, yet a maximum tensile strain of up to 1000 in the core. The maximum axial and hoop compressive stresses of the axle are about -500 MPa and -303 MPa respectively, while radial stresses overall fluctuate in the zero mean stress range. At depths beyond 4.5 mm from the surface layer, all three components are tensile stresses. The axle surface layer is subjected to compressive residual stresses, and crack propagation does not occur if the crack depth is less than 4.5 mm. Nevertheless, cracks propagate accelerates when the crack depth is greater than 4.5 mm. Different crack propagation depth thresholds lead to a larger calculated remaining lifetime for the residual stress-free condition than for the case where 3D residual stresses are taken into account. However, the axle remaining service mileage of the axle of 227000 Km under the most conservative conditions exceeds 3.5 non-destructive inspection (NDI) cycles, with a large safety margin. The experimental results can provide a scientific reference for the development and optimization of NDI cycles for surface-strengthened railway axles.

論文

Tetrahedral triple-Q magnetic ordering and large spontaneous Hall conductivity in the metallic triangular antiferromagnet Co $_{1/3}$ TaS $_{2}$

Park, P.*; Cho, W.*; Kim, C.*; An, Y.*; Kang, Y.-G.*; Avdeev, M.*; Sibille, R.*; 飯田一樹*; 梶本亮一; Lee, K. H.*; et al.

Nature Communications (Internet), 14, p.8346_1 - 8346_9, 2023/12

https://doi.org/10.1038/s41467-023-43853-4

被引用回数：28 パーセンタイル：86.73(Multidisciplinary Sciences)

The triangular lattice antiferromagnet (TLAF) has been the standard paradigm of frustrated magnetism for several decades. The most common magnetic ordering in insulating TLAFs is the 120 $^{circ}$ structure. However, a new triple- chiral ordering can emerge in metallic TLAFs, representing the short wavelength limit of magnetic skyrmion crystals. We report the metallic TLAF Co $_{1/3}$ TaS $_{2}$ as the first example of tetrahedral triple- magnetic ordering with the associated topological Hall effect (non-zero $sigma_{xy}(mathbf{H}=0)$ ). We also present a theoretical framework that describes the emergence of this magnetic ground state, which is further supported by the electronic structure measured by angle-resolved photoemission spectroscopy. Additionally, our measurements of the inelastic neutron scattering cross section are consistent with the calculated dynamical structure factor of the tetrahedral triple- state.

論文

Corrosion fatigue crack growth behavior of a structurally gradient steel for high-speed railway axles

Ao, N.*; Zhang, H.*; Xu, H. H.*; Wu, S. C.*; Liu, D.*; 徐平光; Su, Y. H.; Kang, Q. H.*; Kang, G. Z.*

Engineering Fracture Mechanics, 281, p.109166_1 - 109166_14, 2023/03

https://doi.org/10.1016/j.engfracmech.2023.109166

被引用回数：14 パーセンタイル：81.21(Mechanics)

Considering the complex service environments that high-speed railway axles are subjected to, the fatigue crack growth (FCG) behavior of a structurally gradient axle steel with different pre-crack depths both in air and corrosive medium was investigated at a frequency of 5 Hz. The results indicated that in the high region, FCG rate was dramatically accelerated by corrosion, but the gap narrows as decreased. The accelerated corrosion FCG rate was a comprehensive result of the acceleration effect of the anodic dissolution, hydrogen-enhanced localized plasticity and the retardation effect of corrosion-induced crack-tip blunting. Despite the fact that the corrosion resistance gradually decreased as the pre-crack depth increased, the FCG rate in the corrosive medium gradually decreased. This was because fatigue loading played a more important role than corrosion in accelerating the corrosion FCG rate.

論文

Accelerating the adoption of advanced manufacturing technologies for Gen IV nuclear reactors through international collaboration

Van Rooyen, I. J.*; Ivan, L.*; Messner, M.*; Edwards, L.*; Abonneau, E.*; 上地優; Lowe, S.*; Nilsson, K.-F.*; 岡島智史; Pouchon, M.*; et al.

Proceedings of 4th International Conference on Generation IV and Small Reactors (G4SR-4), p.2 - 12, 2022/10

Developments in advanced manufacturing (AM) are occurring faster than the ability to introduce new materials and methods into design codes. Qualifying new AM technologies for use with nuclear design codes can be a long and complex process. The Generation IV International Forum (GIF) Advanced Manufacturing Materials Engineering Task Force (AMME-TF), focuses on how collaborative AM R&D could be used to decrease time to deployment of Gen-IV reactors. This paper provides a critical review of 2019 and 2021 surveys sampling nuclear reactor vendors, supply chain specialists, regulators, and other experts in GIF member countries. Both surveys confirmed that many AM technologies were considered opportunities by potential end users, although 90% of respondents identified the creation and approval of codes and standards as the greatest obstacle to their adoption. Industry prioritization on AM technologies, components and materials changed significantly during the three-year timespan. Additionally, the paper summarizes a 2021 modeling & simulation workshop that developed ideas on how to accelerate the qualification of AM and synthesizes the survey results and workshop conclusions into a review of critical research gaps and paths to address these gaps, particularly through international collaboration.

論文

Surface coverage dependence of spin-to-charge current across Pt/MoS $_{2}$ /Y $_{3}$ Fe $_{5}$ O $_{12}$ layers via longitudinal spin Seebeck effect

Lee, W.-Y.*; Park, N.-W.*; Kang, M.-S.*; Kim, G.-S.*; Jang, H. W.*; 齊藤英治; Lee, S.-K.*

Journal of Physical Chemistry Letters (Internet), 11(13), p.5338 - 5344, 2020/07

https://doi.org/10.1021/acs.jpclett.0c01502

被引用回数：12 パーセンタイル：54.50(Chemistry, Physical)

The voltage induced by the inverse spin Hall effect (ISHE) is affected by several factors, including the spin Hall angle of the normal metal (NM), the quality and magnetic properties of the ferromagnetic material (FM), and the interface conditions between the NM and FM bilayers in longitudinal spin Seebeck effect (LSSE) measurement. Specifically, the interface conditions in NM/FM systems via LSSE devices play a crucial role in determining the efficiency of spin current injection into the NM layer. In this letter, we report a new approach to controlling the efficiency of spin current injection into a Pt layer across a Pt/Y $_{3}$ Fe $_{5}$ O $_{12}$ (YIG) interface by surface coverage of the intermediate layer. A continuous, large-area multilayer molybdenum dichalcogenide (MoS $_{2}$ ) thin film grown by chemical vapor deposition is inserted between the Pt and YIG layers in the LSSE configuration. We found that, when the large-area multilayer MoS $_{2}$ film was present, the measured ISHE-induced voltage and theoretically calculated spin current in the Pt/MoS $_{2}$ /YIG trilayer increased by 510% and 470%, respectively, compared to those of a Pt/YIG bilayer. The induced voltage and spin current were very sensitive to the surface conductance, which was affected by the surface coverage of the multilayer MoS $_{2}$ films in the LSSE measurement. Furthermore, the theoretically calculated spin current and spin mixing conductance in the trilayer geometry are in qualitatively good agreement with the experimental observations. These measurements enable us to explain the effect of the interface conditions on the spin Seebeck effect in spin transport.

論文

Event structure and double helicity asymmetry in jet production from polarized collisions at = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review D, 84(1), p.012006_1 - 012006_18, 2011/07

https://doi.org/10.1103/PhysRevD.84.012006

被引用回数：34 パーセンタイル：75.56(Astronomy & Astrophysics)

重心エネルギー200GeVでの縦偏極陽子陽子衝突からのジェット生成のイベント構造と二重非対称( $A_{LL}$ )について報告する。光子と荷電粒子がPHENIX実験で測定され、イベント構造がPHYTIAイベント生成コードの結果と比較された。再構成されたジェットの生成率は2次までの摂動QCDの計算で十分再現される。測定された $A_{LL}$ は、一番低い横運動量で-0.00140.0037、一番高い横運動量で-0.01810.0282であった。この $A_{LL}$ の結果を幾つかのの分布を仮定した理論予想と比較する。

論文

Identified charged hadron production in collisions at = 200 and 62.4 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; 秋葉康之*; Al-Bataineh, H.*; Alexander, J.*; 青木和也*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06

https://doi.org/10.1103/PhysRevC.83.064903

被引用回数：194 パーセンタイル：99.37(Physics, Nuclear)

200GeVと62.4GeVでの陽子陽子の中心衝突からのの横運動量分布及び収量をRHICのPHENIX実験によって測定した。それぞれエネルギーでの逆スロープパラメーター、平均横運動量及び単位rapidityあたりの収量を求め、異なるエネルギーでの他の測定結果と比較する。またやスケーリングのようなスケーリングについて示して陽子陽子衝突における粒子生成メカニズムについて議論する。さらに測定したスペクトルを二次の摂動QCDの計算と比較する。

論文

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in and Au+Au collisions at $sqrt{s_{NN}}$ = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; 秋葉康之*; Al-Bataineh, H.*; Alexander, J.*; 青木和也*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

https://doi.org/10.1103/PhysRevC.83.044912

被引用回数：9 パーセンタイル：51.22(Physics, Nuclear)

重いフレーバーのメソンの崩壊からの電子の測定は、このメソンの収量が金金衝突では陽子陽子に比べて抑制されていることを示している。われわれはこの研究をさらに進めて二つの粒子の相関、つまり重いフレーバーメソンの崩壊からの電子と、もう一つの重いフレーバーメソンあるいはジェットの破片からの荷電ハドロン、の相関を調べた。この測定は重いクォークとクォークグルオン物質の相互作用についてのより詳しい情報を与えるものである。われわれは特に金金衝突では陽子陽子に比べて反対側のジェットの形と収量が変化していることを見いだした。

論文

Measurement of neutral mesons in + collisions at = 200 GeV and scaling properties of hadron production

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review D, 83(5), p.052004_1 - 052004_26, 2011/03

https://doi.org/10.1103/PhysRevD.83.052004

被引用回数：185 パーセンタイル：98.31(Astronomy & Astrophysics)

RHIC-PHENIX実験で重心エネルギー200GeVの陽子陽子衝突からの, , と中間子生成の微分断面積を測定した。これらハドロンの横運動量分布のスペクトルの形はたった二つのパラメーター、、のTsallis分布関数でよく記述できる。これらのパラメーターはそれぞれ高い横運動量と低い横運動量の領域のスペクトルを決めている。これらの分布をフィットして得られた積分された不変断面積はこれまで測定されたデータ及び統計モデルの予言と一致している。

論文

Resonant photoemission spectroscopy study of impurity-induced melting in Cr- and Ru-doped Nd $_{1/2}$ A $_{1/2}$ MnO $_{3}$ (A=Ca,Sr)

Kang, J.-S.*; Kim, J. H.*; 関山明*; 笠井修一*; 菅滋正*; Han, S. W.*; Kim, K. H.*; Choi, E. J.*; 木村剛*; 室隆桂之*; et al.

Physical Review B, 68(1), p.012410_1 - 012410_4, 2003/07

A2003-0329.pdf:0.49MB

https://doi.org/10.1103/PhysRevB.68.012410

被引用回数：21 パーセンタイル：67.33(Materials Science, Multidisciplinary)

非常に希薄にCr及びRuをドープしたNd $_{1/2}$ A $_{1/2}$ MnO $_{3}$ (NAMO) (A=Ca,Sr)マンガナイトの電子状態をMn及びCrの2p3d共鳴光電子分光を用いて調べた。すべてのCr及びRuをドープしたNAMOシステムにおいてMnのe $_{g}$ 成分による金属的なフェルミ端が観測され、これらのシステムの金属的な性質をよく説明する。t $_{2g}$ $^{3}$ 配置を取るCrの3d状態は、フェルミエネルギーの下約1.3eVにあり、またCrのe $_{g}$ 状態はフェルミエネルギー近傍のバンド形成には関与していない。Cr及びRuが誘起する強磁性と金属-絶縁体転移は、測定によって得られた電子構造によって理解できる。

論文

Bulk-sensitive photoemission spectroscopy of $A_{2}$ FeMoO $_{6}$ double perovskites (=Sr, Ba)

Kang, J.-S.*; Kim, J. H.*; 関山明*; 笠井修一*; 菅滋正*; Han, S. W.*; Kim, K. H.*; 室隆桂之*; 斎藤祐児; Hwang, C.*; et al.

Physical Review B, 66(11), p.113105_1 - 113105_4, 2002/09

https://doi.org/10.1103/PhysRevB.66.113105

被引用回数：66 パーセンタイル：89.88(Materials Science, Multidisciplinary)

ダブルペロブスカイト構造をとるSr $_{2}$ FeMoO $_{6}$ 及びBa $_{2}$ FeMoO $_{6}$ の電子状態をFeの2p-3d共鳴光電子分光及びMo 4d光イオン化断面積のクーパーミニマムを利用して調べた。フェルミレベル近傍はMoとFeのt $_{2g}$ が強く混ざった状態であり、Feは純粋な+3価のイオンでは無いことがわかった。Feの2p $_{3/2}$ のX線吸収スペクトルはFe $^{2+}$ とFe $^{3+}$ 混合原子価であることを示し、Sr $_{2}$ FeMoO $_{6}$ の方がBa $_{2}$ FeMoO $_{6}$ よりもFe $^{2+}$ 成分が多く、二重交換相互作用が有効に働いていることを示唆する。価電子帯の光電子スペクトルは局所スピン密度近似+Uの計算結果とよく一致する。

口頭

ガンマ線ビームを用いた陽電子寿命イメージング分析の可能性

田久創大*; 平義隆*; 平出哲也; 錦戸文彦*; Kang, H. G.*; 田島英朗*; 小畠藤乃*; 松本謙一郎*; 高橋美和子*; 山谷泰賀*

no journal, ,

陽電子寿命から生体内の新しい生化学的情報を取り出す量子PET(Q-PET)の実現を目指している。しかしながら、例えば、測定した寿命値から、どんな病気なのか、という基礎データは現状全くない。それは、生体内で生きたままの生体組織の陽電子寿命分析が困難であるからである。分子研の極端紫外光研究施設(UVSOR)の6.6MeVガンマ線ビームを利用した、生体を含む試料深部の3次元分析を可能とする陽電子寿命イメージング分析技術を提案する。具体的には、このビームを試料に照射し、PETの原理でイメージングして、陽電子寿命の3次元画像化を実現する。その初期実験結果について報告する。