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Neural network study of the nuclear ground-state spin distribution within a random interaction ensemble
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作者 Deng Liu Alam Noor A +1 位作者 Zhen-Zhen Qin Yang Lei 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第3期216-227,共12页
The distribution of the nuclear ground-state spin in a two-body random ensemble(TBRE)was studied using a general classification neural network(NN)model with two-body interaction matrix elements as input features and t... The distribution of the nuclear ground-state spin in a two-body random ensemble(TBRE)was studied using a general classification neural network(NN)model with two-body interaction matrix elements as input features and the corresponding ground-state spins as labels or output predictions.The quantum many-body system problem exceeds the capability of our optimized NNs in terms of accurately predicting the ground-state spin of each sample within the TBRE.However,our NN model effectively captured the statistical properties of the ground-state spin because it learned the empirical regularity of the ground-state spin distribution in TBRE,as discovered by physicists. 展开更多
关键词 Neural network Two-body random ensemble spin distribution of nuclear ground state
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Low drift nuclear spin gyroscope with probe light intensity error suppression 被引量:4
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作者 Wenfeng Fan Wei Quan +2 位作者 Feng Liu Lihong Duan Gang Liu 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第11期129-133,共5页
A nuclear spin gyroscope based on an alkali-metal–noble-gas co-magnetometer operated in spin-exchange relaxationfree(SERF) regime is a promising atomic rotation sensor for its ultra-high fundamental sensitivity. Howe... A nuclear spin gyroscope based on an alkali-metal–noble-gas co-magnetometer operated in spin-exchange relaxationfree(SERF) regime is a promising atomic rotation sensor for its ultra-high fundamental sensitivity. However, the fluctuation of probe light intensity is one of the main technical error sources that limits the bias stability of the gyroscope. Here we propose a novel method to suppress the bias error induced by probe light intensity fluctuations. This method is based on the inherent magnetic field response characteristics of the gyroscope. By the application of a bias magnetic field, the gyroscope can be tuned to a working point where the output signal is insensitive to probe light intensity variation, referred to herein as ‘zero point’, thus the bias error induced by intensity fluctuations can be completely suppressed. The superiority of the method was verified on a K–Rb–21 Ne co-magnetometer, and a bias stability of approximately 0.01°/h was obtained. In addition, the method proposed here can remove the requirement of the closed-loop control of probe light intensity, thereby facilitating miniaturization of the gyroscope volume and improvement of reliability. 展开更多
关键词 nuclear spin GYROSCOPE spin-EXCHANGE relaxation-free ERROR SUPPRESSION PROBE light intensity
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Study of Decoherence of Elementary Gates Implemented in a Chain of Few Nuclear Spins Quantum Computer Model 被引量:2
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作者 G. V. López P. López 《Journal of Modern Physics》 2012年第1期85-101,共17页
We study the phenomenon of decoherence during the operation of one qubit transformation, controlled-not (CNOT) and controlled-controlled-not (C2NOT) quantum gates in a quantum computer model formed by a linear chain o... We study the phenomenon of decoherence during the operation of one qubit transformation, controlled-not (CNOT) and controlled-controlled-not (C2NOT) quantum gates in a quantum computer model formed by a linear chain of three nuclear spins system. We make this study with different type of environments, and we determine the associated decoherence time as a function of the dissipative parameter. We found that the dissipation parameter to get a well defined quantum gates (without significant decoherence) must be within the range of . We also study the behavior of the purity parameter for these gates and different environments and found linear or quadratic decays of this parameter depending on the type of environments. 展开更多
关键词 DECOHERENCE Not GATE Controlled-Not GATES Controlled-Controlled-Not GATE nuclear spin CHAIN QUANTUM Computer
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Quasi non-Markovian Approach to the Study of Decoherence of a Controlled-Not Quantum Gate in a Chain of Few Nuclear Spins Quantum Computer 被引量:1
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作者 Pablo Carlos López Vázquez Gustavo López Vázquez 《Journal of Modern Physics》 2012年第9期902-917,共16页
We develop in the weak coupling approximation a quasi-non-Markovian master equation and study the phenomenon of decoherence during the operation of a controlled-not (CNOT) quantum gate in a quantum computer model form... We develop in the weak coupling approximation a quasi-non-Markovian master equation and study the phenomenon of decoherence during the operation of a controlled-not (CNOT) quantum gate in a quantum computer model formed by a linear chain of three nuclear spins system with second neighbor Ising interaction between them. We compare with the behavior of the Markovian counterpart for temperature different from zero (thermalization) and at zero temperature for low and high dissipation rates. At low dissipation there is a very small difference between Markovian and quasi no-Markovian at any temperature which is unlikely to be measured, and at high dissipation there is a difference which is likely to be measured at any temperature. 展开更多
关键词 DECOHERENCE CHAIN of nuclear spinS Controlled-Not
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Origin of the finite nuclear spin and its effect in intermediate energy heavy ion collisions 被引量:2
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作者 ZHANG Guoqiang CAO Xiguang +8 位作者 FU Yao MA Yugang CAI Xiangzou WANG Hongwei FANG Deqing CHEN Jingen GUO Wei Tian Wendong LIU Guihua 《Nuclear Science and Techniques》 SCIE CAS CSCD 2012年第1期61-64,共4页
The heavy-ion phase-space exploration (HIPSE) model is used to discuss the origin of the nuclear spin in intermediate energy heavy-ion collision (HIC).The spin of maximal projectile-like fragment is found to depend st... The heavy-ion phase-space exploration (HIPSE) model is used to discuss the origin of the nuclear spin in intermediate energy heavy-ion collision (HIC).The spin of maximal projectile-like fragment is found to depend strongly on impact parameter of a reaction system,while it relates weakly to the collision violence.Some interesting multi-fragmentation phenomena related to the spin are shown.We also found that the excitation energy in the de-excitation stage plays a robust role at the de-excitation stage in HIC. 展开更多
关键词 中能重离子碰撞 核自旋 起源 激发能量 空间探索 影响参数 反应体系 断裂现象
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Optical nuclear spin polarization in quantum dots
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作者 李爱仙 段素青 张伟 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第10期535-539,共5页
Hyperfine interaction between electron spin and randomly oriented nuclear spins is a key issue of electron coherence for quantum information/computation. We propose an efficient way to establish high polarization of n... Hyperfine interaction between electron spin and randomly oriented nuclear spins is a key issue of electron coherence for quantum information/computation. We propose an efficient way to establish high polarization of nuclear spins and reduce the intrinsic nuclear spin fluctuations. Here, we polarize the nuclear spins in semiconductor quantum dot(QD) by the coherent population trapping(CPT) and the electric dipole spin resonance(EDSR) induced by optical fields and ac electric fields. By tuning the optical fields, we can obtain a powerful cooling background based on CPT for nuclear spin polarization. The EDSR can enhance the spin flip–flop rate which may increase the cooling efficiency. With the help of CPT and EDSR, an enhancement of 1300 times of the electron coherence time can be obtained after a 10-ns preparation time. 展开更多
关键词 nuclear spin polarization coherent population trapping electron dipole spin resonance
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Large-scale cluster state generation with nuclear spins in diamonds
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作者 陈琼 冯芒 +1 位作者 杜江峰 海文华 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第1期142-149,共8页
The cluster state is an indispensable resource for one-way quantum computing (lWQC). We propose a practical scheme for constructing cluster states among nuclear spins in nitrogen-vacancy defect centres (NV centres... The cluster state is an indispensable resource for one-way quantum computing (lWQC). We propose a practical scheme for constructing cluster states among nuclear spins in nitrogen-vacancy defect centres (NV centres) in different diamonds. The entanglement of nuclear spins within an NV centre is made by hyperfine coupling via electron spin, and the entanglement between remote NV centres is accomplished using the parity projection of emitted photons. We discus the possibility to build large-scale nuclear-spin cluster states with diamonds. 展开更多
关键词 nitrogen-vacancy defect centre cluster state nuclear spin
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Disorder-enhanced nuclear spin relaxation at Landau level filling factor one
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作者 关童 Benedikt Friess +4 位作者 李永庆 颜世申 Vladimir Umansky Klaus von Klitzing Jurgen H.Smet 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第6期521-527,共7页
The nuclear spin relaxation rate (l/T1) is measured for GaAs two-dimensional (2D) electron systems in the quantum Hall regime with an all-electrical technique for agitating and probing the nuclear spins. A "tilte... The nuclear spin relaxation rate (l/T1) is measured for GaAs two-dimensional (2D) electron systems in the quantum Hall regime with an all-electrical technique for agitating and probing the nuclear spins. A "tilted plateau" feature is observed near the Landau level filling factor v = 1 in 1/T1 versus v. Both the width and magnitude of the plateau increase with decreasing electron density. At low temperatures, lIT1 exhibits an Arrhenius temperature dependence within the tilted plateau regime. The extracted energy gaps are up to two orders of magnitude smaller than the corresponding charge transport gaps. These results point to a nontrivial mechanism for the disorder-enhanced nuclear spin relaxation, in which microscopic inhomogeneities play a key role for the low energy spin excitations related to skyrmions. 展开更多
关键词 nuclear spin relaxation Landau level filling factor one SKYRMIONS
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Effects of N/Z on Spin Distribution of Evaporation Residue Cross Section as a Probe of Nuclear Dissipation
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作者 YE Wei YANG Hong-Wei CHEN Na 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第9期729-732,共4页
The spin distribution of the evaporation residue cross section of nuclei ^194pb, ^200Pb, ^206Pb, and ^200 Os are calculated via a Langevin equation coupled with a statistical decay model. It is shown that with increas... The spin distribution of the evaporation residue cross section of nuclei ^194pb, ^200Pb, ^206Pb, and ^200 Os are calculated via a Langevin equation coupled with a statistical decay model. It is shown that with increasing the neutronto-proton ratio (N/Z) of the system, the sensitivity of the significantly. Moreover, for ^200Os this spin distribution is no spin distribution to the nuclear dissipation is decreased longer sensitive to the nuclear dissipation. These results suggest that to obtain a more accurate pre-saddle viscosity coefficient through the measurement of the evaporation residue spin distribution, it is best to yield those compound systems with low N/Z. 展开更多
关键词 evaporation residue spin distribution N/Z effect nuclear dissipation Langevin equation
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Study of Decoherence on the Teleportation Algorithm in a Chain of Three Nuclear Spins System
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作者 G. V. López P. López 《Journal of Modern Physics》 2013年第1期68-75,共8页
We make a numerical study of decoherence on the teleportation algorithm implemented in a linear chain of three nuclear spins system. We study different types of environments, and we determine the associated decoherenc... We make a numerical study of decoherence on the teleportation algorithm implemented in a linear chain of three nuclear spins system. We study different types of environments, and we determine the associated decoherence time as a function of the dissipative parameter. We found that the dissipation parameter to get a well defined quantum gates (without significant decoherence) must be within the range of γ≤4×10-4 for not thermalized case, which was determined by using the purity parameter calculated at the end of the algorithm. For the thermalized case the decoherence is stablished for very small dissipation parameter, making almost not possible to implement this algorithm for not zero temperature. 展开更多
关键词 TELEPORTATION DECOHERENCE nuclear spin
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Optical pumping and population transfer of nuclear-spin states of caesium atoms in high magnetic fields
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作者 罗军 孙献平 +1 位作者 曾锡之 詹明星 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第4期998-1007,共10页
Nuclear-spin states of gaseous-state Cs atoms in the ground state are optically manipulated using a Ti:sapphire laser in a magnetic field of 1.516 T, in which optical coupling of the nuclear-spin states is achieved t... Nuclear-spin states of gaseous-state Cs atoms in the ground state are optically manipulated using a Ti:sapphire laser in a magnetic field of 1.516 T, in which optical coupling of the nuclear-spin states is achieved through hyperfine interactions between electrons and nuclei. The steady-state population distribution in the hyperfine Zeeman sublevels of the ground state is detected by using a tunable diode laser. Furthermore, the state population transfer among the hyperfine Zeeman sublevels, which results from the collision-induced modification δa(S·I) of the hyperfine interaction of Cs in the ground state due to stochastic collisions between Cs atoms and buffer-gas molecules, is studied at different buffer-gas pressures. The experimental results show that high-field optical pumping and the small change δa(S · I) of the hyperfine interaction can strongly cause the state population transfer and spin-state interchange among the hyperfine Zeeman sublevels. The calculated results maybe explain the steady-state population in hyperfine Zeeman sublevels in terms of rates of optical-pumping, electron-spin flip, nuclear spin flip, and electron-nuclear spin flip-flop transitions among the hyperfine Zeeman sublevels of the ground state of Cs atoms. This method may be applied to the nuclear-spin-based solid-state quantum computation. 展开更多
关键词 high magnetic field optical pumping hyperfine interaction changing nuclear-spin and electron spin state
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Dynamics of nuclear spin-1/2 system in a strong bichromatic RF-field
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作者 LU Hongliang SHI Chunhua QIU Xijun 《Nuclear Science and Techniques》 SCIE CAS CSCD 2009年第1期56-59,共4页
Based on calculating the influence of RF-field with various physical parameters on the dynamics of the spin 1/2 system,it was found that the spin state could be changed up and down by choosing appropriate RF pulses, a... Based on calculating the influence of RF-field with various physical parameters on the dynamics of the spin 1/2 system,it was found that the spin state could be changed up and down by choosing appropriate RF pulses, and the coherent control of the RF pulses could substantially modify the behavior of spin dynamics:quicker change of two states could be produced even for small pulse duration.In addition,the oscillatory structures around the resonant frequency and the propagation features of the pulses depend on the relative phase of the bichromatic RF pulses. 展开更多
关键词 原子能 核四极矩共振 探测原理 试验
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不同耦合构型多自旋体系单重态制备效率研究
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作者 王子文 辛家祥 +1 位作者 魏达秀 姚叶锋 《波谱学杂志》 CAS 2024年第1期67-76,共10页
核自旋单重态是一种特殊的量子态,其存在寿命能远长于纵向弛豫时间(T1),能够被用于研究分子之间的慢扩散和慢运动等动力学过程.单重态的制备是其能成功应用的关键.目前文献中报道了多种制备单重态的方法,这些方法主要适用于孤立的两自... 核自旋单重态是一种特殊的量子态,其存在寿命能远长于纵向弛豫时间(T1),能够被用于研究分子之间的慢扩散和慢运动等动力学过程.单重态的制备是其能成功应用的关键.目前文献中报道了多种制备单重态的方法,这些方法主要适用于孤立的两自旋体系,当单重态所涉及的核自旋受到其它自旋的耦合作用时,单重态的制备效率往往会降低.本文以三自旋体系为例,研究了不同耦合构型下单重态的制备效率受非单重态自旋耦合的影响,模拟结果表明当单重态自旋由弱耦合逐渐变为强耦合时,单重态的制备效率会在单重态自旋与非单重态自旋的耦合呈现对称性时保持一定的稳定性,此特性能够为复杂体系中选择合适的自旋制备单重态提供参考.我们利用N-乙酰-L-天门冬氨酸(NAA)分子的三个质子组成的自旋体系实验验证了以上结论,通过调节NAA分子的酸碱度,所选的三自旋体系能从弱耦合向强耦合转变,实验结果表明:当三自旋中单重态自旋处于强耦合时,单重态的制备效率明显高于弱耦合时的效率. 展开更多
关键词 核磁共振 核自旋单重态 制备效率 N-乙酰-L-天门冬氨酸 脉冲序列 优化控制
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中子自旋回波:研究蛋白质结构域动力学的利器
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作者 孙喆炘 崔腾飞 储祥蔷 《物理》 CAS 北大核心 2024年第3期174-183,共10页
蛋白质作为生物系统这种复杂分子机器的重要组成部分之一,理解它们内部的结构及其在不同时间及空间尺度上的运动,对于研究生命的运作机理至关重要。相较于其他实验手段,中子自旋回波技术能探测到更大时空范围的性质,在研究蛋白质内部的... 蛋白质作为生物系统这种复杂分子机器的重要组成部分之一,理解它们内部的结构及其在不同时间及空间尺度上的运动,对于研究生命的运作机理至关重要。相较于其他实验手段,中子自旋回波技术能探测到更大时空范围的性质,在研究蛋白质内部的结构域动力学方面具有独特的优势。这是一门横跨核物理与核技术、非平衡态统计物理学、分子生物学与蛋白质组学等前沿交叉领域的学科,充满着诸多未知与挑战,也遍布着一探生命奥秘的机遇。文章简述了中子自旋回波实验技术的基本原理和发展历程,阐述其在研究蛋白质结构域动力学方面的方法和技术优势,并介绍了部分实验案例,最后对其应用前景进行探讨与展望。 展开更多
关键词 中子散射 中子自旋回波 蛋白质结构域动力学 核技术及应用
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核能发电用主设备封头锻件制造技术的选择与应用
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作者 孙嫘 毛闯 +1 位作者 杜军毅 易泓宇 《大型铸锻件》 2024年第4期6-11,共6页
基于实际研发制造业绩,重点介绍了反应堆压力壳封头、蒸汽发生器封头、稳压器封头、补水箱封头等多种典型核电主设备封头锻件的制造技术及应用情况,讲述了热拉伸成形工艺、胎模旋压全仿形锻造工艺、胎模旋压与热拉伸复合成形工艺、胎模... 基于实际研发制造业绩,重点介绍了反应堆压力壳封头、蒸汽发生器封头、稳压器封头、补水箱封头等多种典型核电主设备封头锻件的制造技术及应用情况,讲述了热拉伸成形工艺、胎模旋压全仿形锻造工艺、胎模旋压与热拉伸复合成形工艺、胎模旋压半仿形锻造与气割修刨组合成形工艺、拉伸成形与管嘴翻边复合成形工艺等典型工艺的优缺点,总结了封头制造技术的选用原则,为核电封头制造的质量稳定性和标准化生产提供依据。 展开更多
关键词 核能发电 核岛 封头锻件 锻造 拉伸成形 旋压成形 翻边成形 标准化 性能
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Progress of novel diluted ferromagnetic semiconductors with decoupled spin and charge doping: Counterparts of Fe-based superconductors 被引量:5
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作者 Shengli Guo Fanlong Ning 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第9期26-33,共8页
Diluted ferromagnetic semiconductors(DMSs) that combine the properties of semiconductors with ferromagnetism have potential application in spin-sensitive electronic(spintronic) devices. The search for DMS material... Diluted ferromagnetic semiconductors(DMSs) that combine the properties of semiconductors with ferromagnetism have potential application in spin-sensitive electronic(spintronic) devices. The search for DMS materials exploded after the observation of ferromagnetic ordering in Ⅲ-Ⅴ(Ga,Mn)As films. Recently, a series of DMS compounds isostructural to iron-based superconductors have been reported. Among them, the highest Curie temperature TCo f 230 K has been achieved in(Ba,K)(Zn,Mn)2As2. However, most DMSs, including(Ga,Mn)As, are p-type, i.e., the carriers that mediate the ferromagnetism are holes. For practical applications, DMSs with n-type carriers are also advantageous. Very recently,a new DMS Ba(Zn,Co)2As2 with n-type carriers has been synthesized. Here we summarize the recent progress on this research stream. We will show that the homogeneous ferromagnetism in these bulk form DMSs has been confirmed by microscopic techniques, i.e., nuclear magnetic resonance(NMR) and muon spin rotation(μSR). 展开更多
关键词 diluted ferromagnetic semiconductors homogenous ferromagnetism muon spin rotation (IxSR) nuclear magnetic resonance (NMR)
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Statistical Treatment of Low-Energy Nuclear Level Schemes 被引量:2
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作者 M. Gholami M. Kildir A.N. Behkami 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第2期303-308,共6页
The level density parameter and the back shift energy E1 are determined for nuclei with A-values across the whole periodic table from fits to complete level schemes at low excitation energy near the neutron binding en... The level density parameter and the back shift energy E1 are determined for nuclei with A-values across the whole periodic table from fits to complete level schemes at low excitation energy near the neutron binding energies. We find that the energy back shift EI shows complicated behavior and depends on the type of the nucleus, even-even, odd mass, and odd-odd. The spin cut-off factor has also been investigated for nuclei mentioned above. The results are compared with the previous results and different experimental data on level densities. 展开更多
关键词 nuclear structure level density parameters nuclear spin cut-off factor
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Review of nuclear magnetic resonance studies on iron-based superconductors 被引量:1
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作者 马龙 于伟强 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第8期181-197,共17页
The newly discovered iron-based superconductors have triggered renewed enormous research interest in the condensed matter physics community. Nuclear magnetic resonance (NMR) is a low-energy local probe for studying ... The newly discovered iron-based superconductors have triggered renewed enormous research interest in the condensed matter physics community. Nuclear magnetic resonance (NMR) is a low-energy local probe for studying strongly correlated electrons, and particularly important for high-Tc superconductors. In this paper, we review NMR studies on the structural transition, antiferromagnetic order, spin fluctuations, and superconducting properties of several iron-based high-Tc superconductors, including LaFeAsOl_xFx, LaFeAsOl_x, BaFe2As2, Bal_xKxFe2As2, Cao.23Nao.67Fe2As2, BaFe2(Asl_xPx)2, Ba(Fel_xRux)2As2, Ba(Fel_xCox)2As2, Lil+xFeAs, LiFel_xCoxAs, NaFeAs, NaFel_xCoxAs, KyFe2_xSe2, and (T1,Rb)yFe2_xSe2. 展开更多
关键词 iron-based superconductors nuclear magnetic resonance (NMR) spin fluctuation superconduc-tivity
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Optical pumping nuclear magnetic resonance system rotating in a plane parallel to the quantization axis
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作者 丁志超 袁杰 +1 位作者 罗晖 龙兴武 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第11期570-570,共1页
Requested by the authors, the article entitled "Optical pumping nuclear magnetic resonance system rotating in a plane parallel to the quantization axis", published in Chinese Physics B, 2017, Vol. 26, Issue 9, Artic... Requested by the authors, the article entitled "Optical pumping nuclear magnetic resonance system rotating in a plane parallel to the quantization axis", published in Chinese Physics B, 2017, Vol. 26, Issue 9, Article No. 093301, has been withdrawn from the publication. The authors found that the axes in the rotating frame xy'z are not all time-invariant, so Eq. (12) obtained from Eq. (11) is incorrect, and the conclusion is inaccurate. 展开更多
关键词 optical pumping nuclear magnetic resonance spin polarization
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High-Spin States in ^(141)Pm
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作者 朱胜江 顾龙 +12 位作者 王建国 肖志刚 杨韵颐 张明 刘宇 丁怀博 竺礼华 吴晓光 贺创业 李广生 王烈林 郑云 张彪 《Plasma Science and Technology》 SCIE EI CAS CSCD 2012年第6期496-498,共3页
The high-spin states of 141pro nucleus have been studied by using in-beam v-ray spectroscopy technology through the126Te(19F, 4n) reaction at a beam energy of 90 MeV. The previous level scheme has been extended with... The high-spin states of 141pro nucleus have been studied by using in-beam v-ray spectroscopy technology through the126Te(19F, 4n) reaction at a beam energy of 90 MeV. The previous level scheme has been extended with spin up to 49/2 h. Many new levels and transitions are identified. Five collective band structures are observed. Based on systematic comparison with the neighboring nuclei, two bands with strong AI = 1 M1 transitions inside the bands are proposed as the oblate bands with γ--60°, and three bands with large signature splitting have been suggested as the oblate-triaxial deformation with γ--90°. The characteristics for these bands have been discussed. 展开更多
关键词 nuclear structure high spin states oblate band oblate-triaxial band
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