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Effective extraction of Pt(IV) as [PtCl$$_{6}$$]$$^{2-}$$ from hydrochloric acid using a simple urea extractant

上田 祐生; 森貞 真太郎*; 川喜田 英孝*; Wenzel, M.*; Weigand, J. J.*; 大渡 啓介*

Separation and Purification Technology, 277, p.119456_1 - 119456_8, 2021/12



Coexisting normal and intruder configurations in $$^{32}$$Mg

北村 徳隆*; Wimmer, K.*; Poves, A.*; 清水 則孝*; Tostevin, J. A.*; Bader, V. M.*; Bancroft, C.*; Barofsky, D.*; Baugher, T.*; Bazin, D.*; et al.

Physics Letters B, 822, p.136682_1 - 136682_7, 2021/11



Half-integer Shapiro-steps in superconducting qubit with a $$pi$$-Josephson junction

森 道康; 前川 禎通

Applied Physics Express, 14(10), p.103001_1 - 103001_4, 2021/10


A superconducting quantum interference device (SQUID) comprising 0- and $$pi$$-Josephson junctions (JJs), called $$pi$$-SQUID, is studied by the resistively shunted junction model. The $$pi$$-SQUID shows half-integer Shapiro-steps (SS) under microwave irradiation at the voltage $$V$$ = $$(hbar/2e)Omega (n/2)$$, with angular frequency $$Omega$$ and half-integer $$n$$/2 in addition to integer $$n$$. We show that the $$pi$$-SQUID can be a $$pi$$-qubit with spontaneous loop currents by which the half-integer SS are induced. Making the 0- and $$pi$$-JJs equivalent is a key for the half-integer SS and realizing the $$pi$$-qubit.


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

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.


Chiral-spin rotation of non-collinear antiferromagnet by spin-orbit torque

竹内 祐太郎*; 山根 結太*; Yoon, J.-Y.*; 伊藤 隆一*; 陣内 佛霖*; 金井 駿*; 家田 淳一; 深見 俊輔*; 大野 英男*

Nature Materials, 20(10), p.1364 - 1370, 2021/10

 被引用回数:2 パーセンタイル:0(Chemistry, Physical)

Electrical manipulation of magnetic materials by current-induced spin torque constitutes the basis of spintronics. Recent studies have demonstrated electrical controls of ferromagnets and collinear antiferromagnets by spin-orbit torque (SOT). Here we show an unconventional response to SOT of a non-collinear antiferromagnet, which has recently attracted great attention owing to large anomalous Hall effect despite vanishingly small net magnetization. In heterostructures with epitaxial non-collinear antiferromagnet Mn$$_3$$Sn, we observe a characteristic fluctuation of Hall resistance, which is attributed to a persistent rotation of chiral-spin structure of Mn$$_3$$Sn driven by SOT. We find that level of the fluctuation that varies with sample size represents the number of magnetic domains of Mn$$_{3}$$Sn. In addition, Mn$$_3$$Sn thickness dependence of critical current reveals that SOT generated by small current density below 20 MA cm$$^{-2}$$ effectively acts on the chiral-spin structure even in thick Mn$$_3$$Sn above 20 nm. The results provide unprecedented pathways of electrical manipulation of magnetic materials, offering new-concept spintronics devices with unconventional functionalities and low-power consumption.


Implications of the $$Z_{cs}$$(3985) and $$Z_{cs}$$(4000) as two different states

Meng, L.*; Wang, B.*; Wang, G.-J.*; Zhu, S.-L.*

Science Bulletin, 66(20), p.2065 - 2071, 2021/10



Heavy hadronic molecules coupled with multiquark states

山口 康宏; Garc$'i$a-Tecocoatzi, H.*; Giachino, A.*; 保坂 淳; Santopinto, E.*; 竹内 幸子*; 瀧澤 誠*

Few-Body Systems, 62(3), p.33_1 - 33_7, 2021/09

 被引用回数:0 パーセンタイル:0.01(Physics, Multidisciplinary)

本研究では$$Lambda_cbar{D}^{(ast)}-Sigma_c^{(ast)}bar{D}^{(ast)}$$ハドロン分子にコンパクトな$$uudcbar{c}$$コアが結合したハイブリット状態としての$$P_c$$ペンタクォーク状態の理論解析が行われた。相互作用としてヘビークォーク対称性とカイラル対称性を尊重したものが用いられ、結果、$$P_c^+(4312)$$$$P_c^+(4440)$$, $$P_c^+(4457)$$の質量と崩壊幅の実験データを説明することができた。その時、スピン-パリティは$$J^P=1/2^-$$, $$3/2^-$$, $$1/2^-$$と求まった。この解析で、エネルギー順位の構造にはコンパクト状態との結合より導かれたハドロン間相互作用が支配的な働きをしていることが得られ、一方、崩壊幅の決定にはパイオン交換力のテンソル項が重要な働きをしていることが得られた。


Nodal lines and boundary modes in topological Dirac semimetals with magnetism

荒木 康史; 渡邊 成*; 野村 健太郎*

Journal of the Physical Society of Japan, 90(9), p.094702_1 - 094702_9, 2021/09


磁性を持つ線ノード半金属はいくつかの化合物で理論的および実験的に確認されているが、一方で、その磁気秩序と電子の性質の間の関係性についての理解は進んでいない。本研究では磁性線ノード半金属のバルク及び境界面における電子の性質を理解することを目的として、トポロジカルディラック半金属(TDSM)に磁性を導入した系を数値的および解析的に取り扱う。TDSMはスピン縮退したディラック点のペアを持つ物質であり、$$mathrm{Cd_3 As_2}$$及び$$mathrm{Na_3 Bi}$$等が知られている。TDSMの格子模型で電子スピンに結合した磁化を導入してバンド構造を計算することにより、TDSMは磁化の向き及び結合定数に依存して、ワイル半金属または線ノード半金属のいずれかに転移することが示された。これによって得られた磁性線ノード半金属相の電子状態を計算することにより、境界面においては線ノードに対応したドラムヘッド型バンド構造を持つゼロモードが現れることが示された。この境界モードはバルクの整数$$(mathbb{Z})$$トポロジカル数により特徴づけられるものであり、磁壁に局在して現れることが見出された。


Spin-flop phase in a honeycomb antiferromagnet Mn$$_{0.84}$$Mg$$_{0.16}$$TiO$$_{3}$$

社本 真一; 山内 宏樹; 池内 和彦*; Lee, M. K.*; Chang, L.-J.*; Garlea, V. O.*; Hwang, I. Y.*; Lee, K. H.*; Chung, J.-H.*

Journal of the Physical Society of Japan, 90(9), p.093703_1 - 093703_4, 2021/09




Optomagnonic Josephson effect in antiferromagnets

仲田 光樹

Physical Review B, 104(10), p.104402_1 - 104402_12, 2021/09




Half-integer Shapiro steps in strong ferromagnetic Josephson junctions

Yao, Y.*; Cai, R.*; Yang, S.-H.*; Xing, W.*; Ma, Y.*; 森 道康; Ji, Y.*; 前川 禎通; Xie, X.-C.*; Han, W.*

Physical Review B, 104(10), p.104414_1 - 104414_6, 2021/09


We report the experimental observation of half-integer Shapiro steps in the strong ferromagnetic Josephson junction (Nb-NiFe-Nb) by investigating the current-phase relation under radio-frequency microwave excitation. The half-integer Shapiro steps are robust in a wide temperature range from T = 4 to 7 K. The half-integer Shapiro steps could be attributed to co-existence of 0- and $$pi$$-states in the strong ferromagnetic NiFe Josephson junctions with the spatial variation of the NiFe thickness. This scenario is also supported by the high-resolution transmission electron microscopy characterization of the Nb/NiFe/Nb junction.


Lifetime measurements of excited states in $$^{55}$$Cr

Kleis, H.*; Seidlitz, M.*; Blazhev, A.*; Kaya, L.*; Reiter, P.*; Arnswald, K.*; Dewald, A.*; Droste, M.*; Fransen, C.*; M$"o$ller, O.*; et al.

Physical Review C, 104(3), p.034310_1 - 034310_9, 2021/09


ケルン大学のタンデム加速器にて、$$^{48}$$Ca($$^{11}$$B, $$p3n$$)$$^{55}$$Cr反応によって$$^{55}$$Crの励起状態を生成し、そこから脱励起する励起状態の寿命をドップラーシフト反跳距離法を用いて測定した。$$9/2^-_1$$状態から$$5/2^-_1$$状態へ脱励起する$$E2$$遷移の寿命が6.33(46)ps, $$5/2^-_1$$状態から$$3/2^-_1$$状態へ脱励起する$$M1$$励起の寿命が5.61(28)psであることが決定された。その値から$$B(E2)$$, $$B(M1)$$値を引き出し、これらが殻模型計算の値とよく一致することがわかった。小さな$$B(M1)$$値は、$$5/2^-_1$$状態と$$3/2^-_1$$状態が異なる回転バンドに属しているためであると解釈された。


Heavy baryon spectrum with chiral multiplets of scalar and vector diquarks

Kim, Y.*; Liu, Y.-R.*; 岡 眞; 鈴木 渓

Physical Review D, 104(5), p.054012_1 - 054012_18, 2021/09


本論文では、スカラー及びベクトルダイクォークのカイラル有効理論を線形シグマ模型に基づいて構成する。有効理論の主な適用として、チャームまたはボトムクォークを1個含むシングルヘビーバリオンの基底状態と励起状態を記述する。ヘビークォーク($$Q=c, b$$)とダイクォーク間の2体ポテンシャルを用いて、ヘビークォーク・ダイクォーク模型を構築し、$$Lambda_Q$$, $$Sigma_Q$$, $$Xi^{(')}_Q$$, $$Omega_Q$$バリオンの正パリティ及び負パリティ状態のスペクトルを求める。ここで、有効理論に含まれる質量や相互作用パラメータは、格子QCDから得られたダイクォーク質量やヘビーバリオンの実験値を用いて決定される。結果として、擬スカラーダイクォーク質量の逆ヒエラルキーに起因して$$Xi_Q$$(フレーバー$$bar{bf 3}$$)の負パリティ励起状態のスペクトルが、$$Lambda_Q$$とは異なる振る舞いを示すことを示す。一方で、$$Sigma_Q, Xi'_Q$$, $$Omega_Q$$(フレーバー$${bf 6}$$)のスペクトルは、$$Lambda_Q$$と同様である。さらに、我々のヘビークォーク・ダイクォーク模型による結果と実験値やクォーク模型による結果との比較を議論する。


Probing the long-range structure of the $$T^{+}_{cc}$$ with the strong and electromagnetic decays

Meng, L.*; Wang, G.-J.*; Wang, B.*; Zhu, S.-L.*

Physical Review D, 104(5), p.L051502_1 - L051502_8, 2021/09



The Negative-parity spin-1/2 $$Lambda$$ baryon spectrum from lattice QCD and effective theory

Pavao, R.*; Gubler, P.; Fernandez-Soler, P.*; Nieves, J.*; 岡 眞; 高橋 徹*

Physics Letters B, 820, p.136473_1 - 136473_8, 2021/09

The spectrum of the negative-parity spin-1/2 $$Lambda$$ baryons is studied using lattice QCD and hadronic effective theory in a unitarized coupled-channel framework. A direct comparison between the two approaches is possible by considering the hadronic effective theory in a finite volume and with hadron masses and mesonic decay constants that correspond to the situation studied on the lattice. Comparing the energy level spectrum and $$SU(3)$$ flavor decompositions of the individual states, itis found that the lowest two states extracted from lattice QCD can be identified with one of the two $$Lambda$$(1405)-poles and the $$Lambda$$(1670) resonance. The quark mass dependences of these two lattice QCD levels are in good agreement with their effective theory counterparts.


Survival probabilities of charmonia as a clue to measure transient magnetic fields

岩崎 幸生*; 慈道 大介*; 岡 眞; 鈴木 渓

Physics Letters B, 820, p.136498_1 - 136498_6, 2021/09

本論文では、時間依存する空間一様磁場中でのS波チャーモニウムの時間発展を数値的に計算し、各固有状態が磁場の減衰後にどれだけ生き残るかを示す指標(残存確率)を見積もる。このような研究は、RHICやLHCなどで行われている相対論的重イオン衝突実験において瞬間的に生成される磁場の測定(特に、磁場の大きさや磁場の寿命の測定)に役立つことが期待される。本解析では、磁場中で起こる異なるスピン固有状態の混合効果や高軌道励起状態への遷移効果が含まれており、これらの効果は最終的な残存確率に影響を及ぼす。結果として、磁場の寿命が極端に短い場合でさえも残存確率の有意な変化が見られることや、残存確率が初期状態のスピン配位に依存することが判明した。このような残存確率は、スピンパートナー同士(スピン1重項とスピン3重項)の和をとることにより初期配位に依存しない量となり、この量は$$sigma B_0^2$$の関数($$sigma$$は磁場の寿命、$$B_0$$は磁場の最大値に対応するパラメータ)として表されることを示す。


Selective extraction of platinum(IV) from the simulated secondary resources using simple secondary amide and urea extractants

上田 祐生; 森貞 真太郎*; 川喜田 英孝*; 大渡 啓介*

Separations (Internet), 8(9), p.139_1 - 139_15, 2021/09



Steam oxidation of silicon carbide at high temperatures for the application as accident tolerant fuel cladding, an overview

Pham, V. H.; 倉田 正輝; Steinbrueck, M.*

Thermo (Internet), 1(2), p.151 - 167, 2021/09

Since the nuclear accident at Fukushima Daiichi Nuclear Power Station in 2011, a considerable number of studies have been conducted to develop accident tolerant fuel (ATF) claddings for safety enhancement of light water reactors. Among many potential ATF claddings, silicon carbide is one of the most promising candidates with many superior features suitable for nuclear applications. In spite of many potential benefits of SiC cladding, there are some concerns over the oxidation/corrosion resistance of the cladding, especially at extreme temperatures (up to 2000$$^{circ}$$C) in severe accidents. However, the study of SiC steam oxidation in conventional test facilities in water vapor atmospheres at temperatures above 1600$$^{circ}$$C is very challenging. In recent years, several efforts have been made to modify existing or to develop new advanced test facilities to perform material oxidation tests in steam environments typical of severe accident conditions. In this article, the authors outline the features of SiC oxidation/corrosion at high temperatures, as well as the developments of advanced test facilities in their laboratories, and, finally, give some of the current advances in understanding based on recent data obtained from those advanced test facilities.



植田 寛和; 福谷 克之

Vacuum and Surface Science, 64(9), p.430 - 434, 2021/09

A unique molecularly chemisorption of H$$_{2}$$ occurs on some stepped surfaces in addition to the typical adsorption schemes of physisorption and dissociation. In the present study, the rotational state and ${it ortho-to-para (o-p)}$ conversion of the molecularly chemisorbed H$$_{2}$$ on Pd(210) at a surface temperature of 50K were probed by combining a pulsed molecular beam, photo-stimulated desorption and resonance-enhanced multiphoton ionization techniques. We experimentally demonstrated that the ${it (o-p)}$ conversion proceeds with a conversion time constant of $$sim$$2s that is 2-3 orders of magnitude smaller than those reported for physisorption systems. The origins of such fast conversion and the rotational state distribution of H$$_{2}$$ in molecular chemisorption state are discussed.


Structure of the {U$$_{13}$$} polyoxo cluster U$$_{13}$$O$$_{8}$$Cl$$_{x}$$(MeO)$$_{38-x}$$ (x = 2.3, MeO = methoxide)

Fichter, S.*; Radoske, T.*; 池田 篤史

Acta Crystallographica Section E; Crystallographic Communications (Internet), 77(8), p.847 - 852, 2021/08

A new type of polyoxo cluster complex that contains thirteen uranium atoms, {U$$_{13}$$}, was synthesised and characterised as [U$$_{13}$$($$mu$$$$_{4}$$-O$$_{rm oxo}$$)$$_{8}$$($$mu$$$$_{4}$$-O$$_{rm MeO}$$)$$_{2}$$($$mu$$$$_{2}$$-O$$_{rm MeO}$$)$$_{24}$$Cl$$_{x}$$(O$$_{rm MeO}$$)$$_{12-x}$$] (x = 2.3, MeO = methoxide) (I). The complex crystallises from methanol containing tetravalent uranium (U$$^{rm IV}$$) with a basic organic ligand. The characterised {U$$_{13}$$} polyoxo cluster complex possesses a single cubic uranium polyhedron at the centre of the cluster core. The observed shortening of U-O bonds, together with BVS calculations and the overall negative charge (2-) of (I), suggests that the central uranium atom in (I), that forms the single cubic polyhedron, is presumably oxidised to the pentavalent state (U$$^{rm V}$$) from the original tetravalent state (U$$^{rm IV}$$). Complex I is, hence, the first example of a polyoxo cluster possessing a single cubic coordination polyhedron of U$$^{rm V}$$.

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