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論文

Spectroscopy of $$^{187}$$Tl; Shape coexistence

Guo, C. Y.*; Andreyev, A. N.; 他38名*

European Physical Journal A, 60(8), p.165_1 - 165_10, 2024/08

https://doi.org/10.1140/epja/s10050-024-01395-3
 被引用回数：0 パーセンタイル：0.00(Physics, Nuclear)

The prompt and delayed $$gamma$$-ray spectra of $$^{187}$$Tl was studied via the $$^{142}$$Nd($$^{50}$$Cr, $$3p2n$$)$$^{187}$$Tl fusion-evaporation reaction. The collective bands with one-quasiparticle configurations from the 2$$f_{7/2}$$, 1$$h_{9/2}$$, 1$$h_{11/2}$$, and 1$$i_{13/2}$$ orbitals and high-lying structures with possible three-quasiparticle configurations are investigated in terms of the tilted axis cranking covariant density functional theory. At low excitation energy, the rotational bands with one-quasiparticle configurations reflect coexistence of three shapes: prolate, triaxial, and oblate. The possible shapes of two microsecond isomers at high excitation energy are proposed.

論文

Direct observations of dynamic and reverse transformation of Ti-6Al-4V alloy and pure titanium

Guo, B.*; Chen, H.*; Chong, Y.*; Mao, W.; Harjo, S.; Gong, W.; Zhang, Z.*; Jonas, J. J.*; 辻 伸泰*

Acta Materialia, 268, p.119780_1 - 119780_11, 2024/04

https://doi.org/10.1016/j.actamat.2024.119780
 被引用回数：6 パーセンタイル：95.58(Materials Science, Multidisciplinary)

This paper focused on the characterization and mechanism of the dynamic transformation from the alpha to beta phase during the hot deformation of Ti-6Al-4V alloy and pure titanium. The investigation employed in-situ neutron diffraction and atomistic simulations for a comprehensive understanding of the process. Dynamic transformations were observed during deformation of the Ti-6Al-4V alloy and pure titanium below the beta transus temperatures. During isothermal holding after unloading, the in-situ neutron diffraction results for Ti-6Al-4V and pure titanium indicated a sluggish reverse transformation from the beta to alpha phase. The mechanism of dynamic transformation was explored through in-situ neutron diffraction and atomistic simulations, which revealed twofold effects of deformation on dynamic transformation. Firstly, deformation led to a significant rise in the Gibbs energy of the alpha phase relative to the beta phase, expanding the beta phase region and diminishing the alpha phase region. Secondly, deformation lowered the energy barriers associated with dynamic transformation, facilitating the activation of dynamic transformation more readily than in the equilibrium state before deformation.

論文

Oxygen interstitials make metastable $$beta$$ titanium alloys strong and ductile

Chong, Y.*; Gholizadeh, R.*; Guo, B.*; 都留 智仁; Zhao, G.*; 吉田 周平*; 光原 昌寿*; Godfrey, A.*; 辻 伸泰*

Acta Materialia, 257, p.119165_1 - 119165_14, 2023/09

https://doi.org/10.1016/j.actamat.2023.119165
 被引用回数：26 パーセンタイル：97.69(Materials Science, Multidisciplinary)

$$beta$$チタン合金は、優れた歪み硬化能を有する反面、降伏強度が低いという問題を抱えている。ここでは、Ti-12Mo(wt.%)準安定$$beta$$チタン合金の降伏強度の向上における結晶粒の微細化と格子間物質の添加の寄与について検討した。その結果、結晶粒の微細化は材料を強化するどころか、この合金の極限引張強度を低下させることがわかった。この予想外の異常な挙動は、ひずみ誘起$$alpha^{primeprime}$$マルテンサイト相変態が著しく促進されたことに起因しており、その場観察放射光X線回折分析により、この相が$$beta$$相よりはるかに軟らかいことが初めて明らかになった。また、酸素添加と結晶粒微細化の組み合わせにより、Ti-12Mo-0.3O(wt.%)合金において前例のない強度と延性の相乗効果が得られることが判明した。この三元合金における酸素溶質には2つの有利な点がある。第一に、溶質酸素は、微細な組織においても、歪みによる$$alpha^{primeprime}$$マルテンサイト相への変態を大きく抑制し、過剰な$$alpha^{primeprime}$$マルテンサイトによる軟化効果を回避することができる。次に、アトムプローブトモグラフィーで明らかになったように、酸素溶質が双晶境界に偏析しやすい。これにより、$${332}langle113rangle$$変形双晶の成長が抑制され、より広範な双晶の核生成が促進される。本研究で得られた知見は、強靭な準安定$$beta$$チタン合金を設計するための費用対効果の高い根拠となり、この高強度対重量構造材料のさらなる普及に大きな意味を持つ。

論文

3D-printed epidermal sweat microfluidic systems with integrated microcuvettes for precise spectroscopic and fluorometric biochemical assays

Yang, D. S.*; Wu, Y.*; Kanatzidis, E. E.*; Avila, R.*; Zhou, M.*; Bai, Y.*; Chen, S.*; 関根 由莉奈; Kim, J.*; Deng, Y.*; et al.

Materials Horizons, 10(11), p.4992 - 5003, 2023/09

https://doi.org/10.1039/D3MH00876B
 被引用回数：12 パーセンタイル：80.32(Chemistry, Multidisciplinary)

本論文では、ハード及びソフトハイブリッド材料システムでの3Dプリントによって形成されたマイクロ流体ネットワーク、統合バルブ、およびマイクロスケール光学キュベットにより、汗成分に対してその場で分光および蛍光分析した成果を紹介する。一連の試験により、これらのマイクロキュベットシステムが汗中の銅、塩化物、グルコースの濃度と汗のpHを実験室レベルの精度と感度で評価できることが実証された。

論文

Unexpected dynamic transformation from $$alpha$$ phase to $$beta$$ phase in zirconium alloy revealed by in-situ neutron diffraction during high temperature deformation

Guo, B.*; Mao, W.; Chong, Y.*; 柴田 曉伸*; Harjo, S.; Gong, W.; Chen, H.*; Jonas, J. J.*; 辻 伸泰*

Acta Materialia, 242, p.118427_1 - 118427_11, 2023/01

https://doi.org/10.1016/j.actamat.2022.118427
 被引用回数：11 パーセンタイル：71.18(Materials Science, Multidisciplinary)

Dynamic transformation from alpha (HCP) to beta (BCC) phase in a zirconium alloy was revealed by the use of in-situ neutron diffraction during hot compression. The dynamic transformation was unexpectedly detected during isothermal compression at temperatures of 900$$^{circ}$$C and 950$$^{circ}$$C (alpha + beta two-phase region) and strain rates of 0.01 s$$^{-1}$$ and 0.001 s$$^{-1}$$, even though equilibrium two-phase states were achieved prior to the hot compression. Dynamic transformation was accompanied by diffusion of Sn from beta to alpha phase, which resulted in changes of lattice parameters and a characteristic microstructure of alpha grains. The details of dynamic transformation are discussed using the evolution of lattice constants.

論文

Ultrahigh yield strength and large uniform elongation achieved in ultrafine-grained titanium containing nitrogen

Chong, Y.*; 都留 智仁; Guo, B.*; Gholizadeh, R.*; 井上 耕治*; 辻 伸泰*

Acta Materialia, 240, p.118356_1 - 118356_15, 2022/11

https://doi.org/10.1016/j.actamat.2022.118356
 被引用回数：31 パーセンタイル：94.20(Materials Science, Multidisciplinary)

本研究では、室温でのチタンの引張特性と変形挙動に及ぼす窒素含有量と結晶粒径の影響を体系的に調査した。巨大ひずみ加工と焼鈍により、超高降伏強度(1.04GPa)と大きな均一伸び(10%)の前例のない相乗効果を組み合わせた、完全再結晶微細構造を備えた超微細粒(UFG)Ti-0.3wt.%N合金が得られた。Ti-0.3wt.%N合金の硬化およびひずみ硬化メカニズムは、変形下部構造の観察と第一原理計算によって包括的に研究された。UFG Ti-0.3wt.%Nの優れた強度/延性バランスへの窒素の寄与は2倍であることが明らかになった。粒子内の窒素原子は、八面体から六面体のサイトへの窒素のシャッフルにより、角柱面上の$$<a>$$転位の運動を強く妨げ、純Tiの6倍の摩擦応力の増加を引き起こした。さらに、Ti-0.3wt.%N合金の柱面と錐面の間の積層欠陥エネルギー差が大幅に減少することで、$$<c+a>$$転位の活性化が容易になり、ひずみ硬化率の向上に寄与した。我々の実験的および理論的計算研究は、延性を大幅に犠牲にすることなく手頃な価格の高強度チタンの設計に関する知見を与える。

論文

First observation of the decay of the 13/2$$^+$$ isomer in $$^{183}$$Hg and $$B$$(${it M}$2) systematics of neutron transitions across the nuclear chart

Huang, H.*; Zhang, W. Q.*; Andreyev, A. N.; Liu, Z.*; Seweryniak, D.*; Li, Z. H.*; Guo, C. Y.*; Barzakh, A. E.*; Van Duppen, P.*; Andel, B.*; et al.

Physics Letters B, 833, p.137345_1 - 137345_8, 2022/10

https://doi.org/10.1016/j.physletb.2022.137345
 被引用回数：1 パーセンタイル：19.87(Astronomy & Astrophysics)

The decay of the 13/2$$^+$$ isomeric state in $$^{183}$$Hg was observed for the first time following the $$alpha$$ decay of the 13/2$$^+$$ isomer in $$^{187}$$Pb produced in the $$^{142}$$Nd$$(^{50}$$Cr$$, 2p3n)$$ reaction. Using $$alpha$$-$$gamma$$ delayed coincidence measurements, the half-life of this isomer was measured to be 290(30) $$mu$$s. This isomer is proposed to deexcite by an unobserved low-energy $$M$$2 transition to the known 9/2$$^-$$ member of a strongly prolate-deformed 7/2$$^-$$[514] band, followed by a 105-keV $$M$$1 transition to the bandhead. A lower limit of B($$M$$2)$$geq$$0.018 W.u. was deduced for the unobserved transition. The presumed retardation is proposed to be due to the notable shape change between the initial, nearly spherical, and the final, strongly deformed, states. A similar scenario is also considered for the 13/2$$^+$$ isomer in $$^{181}$$Hg, suggesting both are cases of shape isomers. The B($$M$$2) systematics of neutron transitions across the nuclear chart is discussed.

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

First observation of a shape isomer and a low-lying strongly-coupled prolate band in neutron-deficient semi-magic $$^{187}$$Pb

Zhang, 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

https://doi.org/10.1016/j.physletb.2022.137129
 被引用回数：6 パーセンタイル：71.20(Astronomy & Astrophysics)

Prompt and delayed $$gamma$$-ray spectroscopy of the neutron-deficient, semi-magic isotope $$^{187}$$Pb has been performed at the Argonne Gas-Filled Analyzer. A new 5.15(15)-$$mu$$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 $$^{185}$$Hg. Based on this similarity and on the result of the potential-energy surface calculations, the new isomer in $$^{187}$$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 $$alpha$$-decay and laser spectroscopy studies present evidence for triple shape coexistence at low energy in the negative-parity configurations of $$^{187}$$Pb, which is well reproduced by the potential-energy surface calculations.

論文

The $$^{59}$$Fe(n,$$gamma$$)$$^{60}$$Fe cross section from the surrogate ratio method and its effect on the $$^{60}$$Fe nucleosynthesis

Yan, S. Q.*; Li, X. Y.*; 西尾 勝久; Lugaro, M.*; Li, Z. H.*; 牧井 宏之; Pignatari, M.*; Wang, Y. B.*; Orlandi, R.; 廣瀬 健太郎; et al.

Astrophysical Journal, 919(2), p.84_1 - 84_7, 2021/10

https://doi.org/10.3847/1538-4357/ac12ce
 被引用回数：4 パーセンタイル：24.65(Astronomy & Astrophysics)

The long-lived $$^{60}$$Fe (with a half-life of 2.62 Myr) is a crucial diagnostic of active nucleosynthesis in the Milky Way galaxy and in supernovae near the solar system. The neutron-capture reaction $$^{59}$$Fe(n,$$gamma$$)$$^{60}$$Fe on $$^{59}$$Fe (half-life=44.5 days) is the key reaction for the production of $$^{60}$$Fe in massive stars. This reaction cross section has been previously constrained by the Coulomb dissociation experiment, which offered partial constraint on the E1 $$gamma$$-ray strength function but a negligible constraint on the M1 and E2 components. In this work, for the first time, we use the surrogate ratio method to experimentally determine the $$^{59}$$Fe(n,$$gamma$$)$$^{60}$$Fe cross sections in which all the components are included. We derived a Maxwellian-averaged cross section of 27.5$$pm$$3.5 mb at $$kT$$ = 30 keV and 13.4$$pm$$1.7 mb at $$kT$$ = 90 keV, roughly 10%-20% higher than previous estimates. We analyzed the impact of our new reaction rates in nucleosynthesis models of massive stars and found that uncertainties in the production of $$^{60}$$Fe from the $$^{59}$$Fe(n,$$gamma$$)$$^{60}$$Fe rate are at most 25$$%$$. We conclude that stellar physics uncertainties now play a major role in the accurate evaluation of the stellar production of $$^{60}$$Fe.

論文

Ultra-fine CeO$$_{2}$$ particles triggered strong interaction with LaFeO$$_{3}$$ framework for total and preferential CO oxidation

Zheng, Y.*; Xiao, H.*; Li, K.*; Wang, Y.*; Li, Y.*; Wei, Y.*; Zhu, X.*; Li, H.-W.*; 松村 大樹; Guo, B.*; et al.

ACS Applied Materials & Interfaces, 12(37), p.42274 - 42284, 2020/09

https://doi.org/10.1021/acsami.0c10271
 被引用回数：26 パーセンタイル：72.77(Nanoscience & Nanotechnology)

Interactions between the active components with the support are one of the fundamentally factors in determining the catalytic performance of a catalyst. In this study, we investigated the interaction between CeO$$_{2}$$ and LaFeO$$_{3}$$, the two important oxygen storage materials in catalysis area, by tuning the sizes of CeO$$_{2}$$ particles and highlight a two-fold effect of the strong oxide-oxide interaction in determining the catalytic activity and selectivity for preferential CO oxidation in hydrogen feeds. It is found that the anchoring of ultra-fine CeO$$_{2}$$ particles at the framework of three-dimensional-ordered macroporous LaFeO$$_{3}$$ surface results in a strong interaction between the two oxides that induces the formation of abundant uncoordinated cations and oxygen vacancy at the interface. This discovery demonstrates that in hybrid oxide-based catalysts, tuning the interaction among different components is essential for balancing the catalytic activity and selectivity.

論文

Spectroscopic and first-principles investigations of iodine species incorporation into ettringite; Implications for iodine migration in cement waste forms

Guo, B.*; Xiong, Y.*; Chen, W.*; Saslow, S. A.*; 香西 直文; 大貫 敏彦*; Dabo, I.*; 笹木 恵子*

Journal of Hazardous Materials, 389, p.121880_1 - 121880_11, 2020/05

https://doi.org/10.1016/j.jhazmat.2019.121880
 被引用回数：50 パーセンタイル：89.28(Engineering, Environmental)

To elucidate retention mechanism of cement waste form for radioactive iodine, this paper investigated interaction mechanism between iodine and ettringite, which is a component mineral of cement and has anion exchange ability. We revealed that ettringite has a high capacity for accommodating IO$$_{3}$$$$^{-}$$ via anion substitution for SO$$_{4}$$$$^{2-}$$. The combined iodine K-edge extended X-ray absorption fine structure spectra and first-principles calculations using density functional theory suggested that IO$$_{3}$$$$^{-}$$ was stabilized in ettringite by hydrogen bonding and electrostatic forces. The bonding charge density analysis of the substituted IO$$_{3}$$$$^{-}$$ into the ettringite structure revealed the interaction between intercalated IO$$_{3}$$$$^{-}$$ with the structural water molecules. These results provided valuable insight into the long-term stabilization of anionic iodine species and their migration in cementitious nuclear waste repository or alkaline environments.

論文

Passive sweat collection and colorimetric analysis of biomarkers relevant to kidney disorders using a soft microfluidic system

Zhang, Y.*; Guo, H.*; Kim, S. B.*; Wu, Y.*; Ostojich, D.*; Park, S. H.*; Wang, X.*; Weng, Z.*; Li, R.*; Bandodkar, A. J.*; et al.

Lab on a Chip, 19(9), p.1545 - 1555, 2019/05

https://doi.org/10.1039/C9LC00103D
 被引用回数：181 パーセンタイル：99.69(Biochemical Research Methods)

汗中のバイオマーカーおよび非侵襲的な方法で汗を集める方法は、健康および生理学的状態の評価のための汗利用の関心を生み出し、スポーツから臨床医学までの範囲の潜在的用途がある。本論文は、皮膚密着型のマイクロ流体システムを用いた2つの結果について述べる。(1)簡易な身体的および心理的刺激による汗の採取、(2)酵素化学および比色アプローチによる汗中のクレアチニンおよび尿素の濃度の検出。結果、乳児や高齢者などを対象に日常的で非薬理学的な汗の捕捉が可能になり、腎臓疾患のスクリーニング/モニタリングに汗を使用する可能性が示された。

論文

The $$^{95}$$Zr($$n, gamma$$)$$^{96}$$Zr cross section from the surrogate ratio method and its effect on $$s$$-process nucleosynthesis

Yan, S. Q.*; Li, Z. H.*; Wang, Y. B.*; 西尾 勝久; Lugaro, M.*; Karakas, A. I.*; 牧井 宏之; Mohr, P.*; Su, J.*; Li, Y. J.*; et al.

Astrophysical Journal, 848(2), p.98_1 - 98_8, 2017/10

https://doi.org/10.3847/1538-4357/aa8c74
 被引用回数：6 パーセンタイル：23.14(Astronomy & Astrophysics)

The $$^{95}$$Zr($$n, gamma$$)$$^{96}$$Zr reaction cross section is crucial in the modelling of $$s$$-process nucleosynthesis in asymptotic giant branch stars because it controls the operation of the branching point at the unstable $$^{95}$$Zr and the subsequent production of $$^{96}$$Zr. We have carried out the measurement of the $$^{90}$$Zr($$^{18}$$O,$$^{16}$$O) and $$^{94}$$Zr($$^{18}$$O,$$^{16}$$O) reactions and obtained the $$gamma$$-decay probability ratio of $$^{92}$$Zr$$^{*}$$ and $$^{96}$$Zr$$^{*}$$ to determine the $$^{95}$$Zr($$n, gamma$$)$$^{96}$$Zr reaction cross sections with the surrogate ratio method. We tested our deduced maxwellian-averaged cross section in stellar models with masses between 2 and 6 $$M_{odot}$$ and metallicities 0.014 and 0.03. The largest changes - up 80 % variations in $$^{96}$$Zr - are seen in the models of 3-4 $$M_{odot}$$, where the $$^{22}$$Ne neutron source is mildly activated. The new rate can still provide a match to data from meteoritic stardust silicon carbide grains, provided the maximum mass of the parent stars is below 4 $$M_{odot}$$, for a metallicity of 0.03.

論文

Uniaxial pressure effect on the magnetic ordered moment and transition temperatures in BaFe$$_{2-x}$$T$$_{x}$$As$$_{2}$$ ($$T$$ = Co,Ni)

Tam, D. M.*; Song, Y.*; Man, H.*; Cheung, S. C.*; Yin, Z.*; Lu, X.*; Wang, W.*; Frandsen, B. A.*; Liu, L.*; Gong, Z.*; et al.

Physical Review B, 95(6), p.060505_1 - 060505_6, 2017/02

https://doi.org/10.1103/PhysRevB.95.060505
 被引用回数：24 パーセンタイル：69.55(Materials Science, Multidisciplinary)

We use neutron diffraction and muon spin relaxation to study the effect of in-plane uniaxial pressure on the antiferromagnetic (AF) orthorhombic phase in BaFe$$_{2-x}$$T$$_{x}$$As$$_{2}$$ and its Co- and Ni-substituted members near optimal superconductivity. In the low-temperature AF ordered state, uniaxial pressure necessary to detwin the orthorhombic crystals also increases the magnetic ordered moment, reaching an 11% increase under 40 MPa for BaFe$$_{1.9}$$Co$$_{0.1}$$As$$_2$$, and a 15% increase for BaFe$$_{1.915}$$Ni$$_{0.085}$$As$$_2$$. We also observe an increase of the AF ordering temperature ($$T_N$$) of about 0.25 K/MPa in all compounds, consistent with density functional theory calculations that reveal better Fermi surface nesting for itinerant electrons under uniaxial pressure. The doping dependence of the magnetic ordered moment is captured by combining dynamical mean field theory with density functional theory, suggesting that the pressure-induced moment increase near optimal superconductivity is closely related to quantum fluctuations and the nearby electronic nematic phase.

論文

Volume-wise destruction of the antiferromagnetic Mott insulating state through quantum tuning

Frandsen, B. A.*; Liu, L.*; Cheung, S. C.*; Guguchia, Z.*; Khasanov, R.*; Morenzoni, E.*; Munsie, T. J. S.*; Hallas, A. M.*; Wilson, M. N.*; Cai, Y.*; et al.

Nature Communications (Internet), 7, p.12519_1 - 12519_8, 2016/08

https://doi.org/10.1038/ncomms12519
 被引用回数：34 パーセンタイル：75.84(Multidisciplinary Sciences)

RENiO$$_3$$ (RE = rare-earth element) and V$$_2$$O$$_3$$ are archetypal Mott insulator systems. When tuned by chemical substitution (RENiO$$_3$$) or pressure (V$$_2$$O$$_3$$), they exhibit a quantum phase transition (QPT) between an antiferromagnetic Mott insulating state and a paramagnetic metallic state. Because novel physics often appears near a Mott QPT, the details of this transition, such as whether it is first or second order, are important. Here, we demonstrate through muon spin relaxation/rotation experiments that the QPT in RENiO$$_3$$ and V$$_2$$O$$_3$$ is first order: the magnetically ordered volume fraction decreases to zero at the QPT, resulting in a broad region of intrinsic phase separation, while the ordered magnetic moment retains its full value until it is suddenly destroyed at the QPT. These findings bring to light a surprising universality of the pressure-driven Mott transition, revealing the importance of phase separation and calling for further investigation into the nature of quantum fluctuations underlying the transition.

論文

Examination of the surrogate ratio method for the determination of the $$^{93}$$Zr(n,$$gamma$$)$$^{94}$$Zr cross section with $$^{90,92}$$Zr($$^{18}$$O,$$^{16}$$O)$$^{92,94}$$Zr reactions

Yan, S. Q.*; Li, Z. H.*; Wang, Y. B.*; 西尾 勝久; 牧井 宏之; Su, J.*; Li, Y. J.*; 西中 一朗; 廣瀬 健太郎; Han, Y. L.*; et al.

Physical Review C, 94(1), p.015804_1 - 015804_5, 2016/07

https://doi.org/10.1103/PhysRevC.94.015804
 被引用回数：7 パーセンタイル：46.99(Physics, Nuclear)

The relative $$gamma$$-decay probability ratios of the neutron resonance states in $$^{94}$$Zr and $$^{92}$$Zr populated via two neutron transfer reactions, $$^{92}$$Zr($$^{18}$$O,$$^{16}$$O)$$^{94}$$Zr and $$^{90}$$Zr($$^{18}$$O,$$^{16}$$O)$$^{92}$$Zr, have been measured to test the validity of the surrogate ratio method (SRM) in determining the (n,$$gamma$$) reaction cross section. The cross sections of the $$^{93}$$Zr(n,$$gamma$$)$$^{94}$$Zr reaction are derived from the experimentally obtained ratios and the cross sections of the $$^{91}$$Zr(n,$$gamma$$)$$^{92}$$Zr reaction in the equivalent neutron energy range of $$E_{rm n}$$ = 0 - 8 MeV. The deduced cross sections of $$^{93}$$Zr(n,$$gamma$$)$$^{94}$$Zr reaction agree with the directly measured ones in the low-energy region, and with the evaluated ENDF/B-VII.1 data at higher energies of $$E_{rm n} >$$ 3 MeV. The agreement supports the concept of the SRM method to indirectly determine the (n,$$gamma$$) reaction cross sections.

論文

In-beam $$gamma$$ spectroscopy of the even-even nucleus $$^{190}$$Pt

Li, G. S.*; Liu, M. L.*; Zhou, X. H.*; Zhang, Y. H.*; Liu, Y. X.*; Zhang, N. T.*; Hua, W.*; Zheng, Y. D.*; Fang, Y. D.*; Guo, S.*; et al.

Physical Review C, 89(5), p.054303_1 - 054303_9, 2014/05

https://doi.org/10.1103/PhysRevC.89.054303
 被引用回数：5 パーセンタイル：36.81(Physics, Nuclear)

タンデム加速器で88MeVにまで加速された$$^{18}$$Oビームを用いて$$^{176}$$Yb($$^{18}$$O, 4$$n$$)反応を起こし、$$^{190}$$Ptの高スピン準位を調べた。その結果、$$nu$$ $$i^{-2}_{13/2}$$ $$nu$$ $$h^{-1}_{9/2}$$ $$nu$$ $$j^{-1}$$1(ここで$$nu j$$は$$nu p_{3/2}$$もしくは$$nu f_{5/2}$$)配位による正パリティバンドを大幅に拡張するとともに新しく負パリティバンドを同定し、$$nu$$ $$i^{-3}_{13/2}$$ $$nu$$ $$j^{-1}$$配位を持つことを明らかにした。また、イラスト準位においてスピンの増加に伴い振動から回転へと構造変化を起こしている可能性について議論した。さらにバンド特性を明らかにするためにTotal Routhian surface計算を行った。

論文

Development of a GEM-TPC for H-dibaryon search experiment at J-PARC

佐甲 博之; Ahn, J. K.*; Baek, K. H.*; Bassalleck, B.*; Fujioka, H.*; Guo, L.*; 長谷川 勝一; Hicks, K.*; Honda, R.*; Hwang, S. H.*; et al.

Journal of Instrumentation (Internet), 9(4), p.C04009_1 - C04009_10, 2014/04

https://doi.org/10.1088/1748-0221/9/04/C04009
 被引用回数：3 パーセンタイル：15.19(Instruments & Instrumentation)

($$K^+$$,$$K^-$$)反応によるHダイバリオン探索実験(J-PARC E42)のためのTPCの開発を行っている。TPCにおいてHが2個の$$pi^{-}$$と2個の$$p$$に崩壊する事象を測定する。TPCのドリフト体積は50cm直径、55cmドリフト長を持つ8角柱構造をしておりAr-CH$$_4$$ガスを使用する。増幅部には3層のGEMを使用する。荷電粒子の運動量測定のためTPCにはドリフト電場と平行に鉛直方向の1Tの双極磁場を超伝導ヘルムホルツ型磁石によりかける。H崩壊のアクセプタンスを最大にするためダイアモンド標的がTPC内部の筒状の穴に設置される。さらに、超高レートの$$K^-$$ビームをTPCに直接照射するため陽イオンフィードバックを極力抑制必要がある。このためTPCにGEMとgating gridを採用した。

論文

Rotational band properties of $$^{173}$$W

Wang, H. X.*; Zhang, Y. H.*; Zhou, X. H.*; Liu, M. L.*; Ding, B.*; Li, G. S.*; Hua, W.*; Zhou, H. B.*; Guo, S.*; Qiang, Y. H.*; et al.

Physical Review C, 86(4), p.044305_1 - 044305_11, 2012/10

AA2012-0752.pdf:0.78MB

https://doi.org/10.1103/PhysRevC.86.044305
 被引用回数：5 パーセンタイル：32.25(Physics, Nuclear)

High-spin states in $$^{173}$$W have been studied using the $$^{150}$$Nd($$^{28}$$Si,5$$n$$)$$^{173}$$W reaction at beam energies of 135 and 140 MeV. The previously known bands associated with the 7/2$$^+$$[633], 5/2$$^-$$[512], and 1/2$$^-$$[521] configurations are extended significantly, and the unfavored signature branch of the 1/2$$^-$$[521] band is established for the first time. The band properties, such as level spacings, band-crossing frequencies, alignment gains, and signature splittings, are discussed with an emphasis on the low-spin signature inversion observed in the 5/2$$^-$$[512] band. By comparing the experimental $$B$$($$M$$1)/$$B$$($$E$$2) ratios with the theoretical values, we conclude that the configuration of the 5/2$$^-$$[512] band is quite pure at low spins without appreciable admixture of the 5/2$$^-$$[523] orbit, in conflict with the particle rotor model calculated results.

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