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Magnetic properties of small Fe clusters: a nonorthogonal Hamiltonian study

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原子与分子物理学报 2000年第4期17卷 583-588页

作者： ren Yun 1.2 ,SUN hou qian 1.2 , {1. Bao lin 1. LUO You hua 1. {1. Guang hou 1.1. National Laboratory of Solid State Microstructures and department of physics, nanjing university, nanjing 21.093 2.Yancheng Institute of Technology, Jia 南京大学固体微结构物理国家重点实验室江苏南京 210093

We calculate the magnetic properties of small Fe N clusters( N =2～7,9,1.,1.) by using a parameterized Hubbard tight binding spd band model Hamiltonian, with the parameters obtained from nonorthogonal Hamiltonian parameters. the average magnetic moments, and the spin polarized charge distribution within clusters are in agreement with those obtained by first principle and tight binding calculations. The effect of the nonorthogonal basis is discussed.

关键词：铁团磁性 Hubbard模型

A new approximating method for Holstein model

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Science china({1.,Mechanics & Astronomy) 2010年第1期53卷 44-48页

作者： ren XueZao 1., LIAO Xu 1., LI Lei 1.& {1. KeLin 2 1.School of Science, Southwest university of Science and Technology, Mian Yang 621.1., china 2 department of Modern physics, university of Science and Technology of china, Hefei 230026, china School of Science Southwest University of Science and Technology Mian Yang China department of Modern {1. University of Science and Technology of China Hefei China

A new approach-the method of coherent state orthogonal expansion is developed for one-dimensional Holstein model. In zeroth order approximation, the formula of ground state energy is deduced analytically and the solutions in strong- and weak-coupling limits are obtained correctly. When the trial wave-function of ground state is expanded to the second order, the obtained ground state energy agrees quite well with that calculated by numerical method in all coupling regimes. The present approach can be easily generalized to the situations of higher dimensions and more electrons.

关键词： coherent-state orthogonal expansion polaron simulated annealing method

Nonlocal symmetries,soliton-cnoidal wave solution and soliton molecules to a(2+1.-dimensional modified KdV system

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Communications in Theoretical physics 2024年第4期76卷 14-21页

作者： Jianyong wang Bo {1. department of Mathematics and {1. Quzhou UniversityQuzhou 324000China department of Mathematics Zhejiang University of TechnologyHangzhou 310014China

A(2+1.-dimensional modified KdV(2DmKdV)system is considered from several ***,residue symmetry,a type of nonlocal symmetry,and the Bäcklund transformation are obtained via the truncated Painlevéexpansion ***,the residue symmetry is localized to a Lie point symmetry of a prolonged system,from which the finite transformation group is ***,the integrability of the 2DmKdV system is examined under the sense of consistent tanh expansion ***,explicit soliton-cnoidal wave solutions are ***,abundant patterns of soliton molecules are presented by imposing the velocity resonance condition on the multiple-soliton solution.

关键词： soliton-cnoidal wave solution nonlocal symmetry soliton molecule (2+1.-dimensional modified KdV system

FLUX　DYNAMICS　OF　TISr2Ca2Cu3Oy　SUPERCONDUCTOR　IN　THE　TIME　WINDOW　OF　MILLISECONDS

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南京大学学报(自然科学) 1995年第3期 508-509页

作者： Ding Shiying 1. wang Guoqiang 1. {1. Cong 1. Lin Jianwei 2) Yao Xixian 1.( 1.Departement of physics and Center for Advance Studies in Science and Technology of Microstructures, nanjing university, nanjing, 21.093, PRC 2)department of Math and physics,

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关键词： flux dynamics ac susceptibility T1.1.23 superoonductor

Orientational Domains at Room Temperature in La_(0.33) Ca_(0.67) MnO_3 Perovskite

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Wuhan university Journal of Natural Sciences 1999年第4期4卷 415-422页

作者： wang {1. hui 1.2) ,GUI Jia nian 1.2) ,ZHU Yi mei 2) , A. R. Moodenbaugh 2) 1. department of physics, Wuhan university, Wuhan 430072, china 2. department of Applied Science, Brookhaven National Laboratory, Upton, NY 1.973 Wuhan university Department of Physics Wuhan China (GRID:grid.49470.3e) (ISNI:***) Brookhaven National Laboratory Department of Applied Science Upton (GRID:grid.202665.5) (ISNI:***) Brookhaven National Laboratory Department of Applied Science Upton (GRID:grid.202665.5) (ISNI:***)

Orientational domains at room temperature in orthorhombic perovskite La 0.33 Ca 0.67 MnO 3 were studied by group theory and observed systematically using transmission electron microscopy. There are six orientational variants ( A, A', B,B', C and C' ) in orthorhombic perovskite La 0.33 Ca 0.67 MnO 3. Their orthorhombic b O directions are parallel to the a P, b P and c P directions of the cubic prototypic perovskite, respectively. In each case there are two orientational variants (e.g., A and A' ) with their a O and c O axes interchanged. Among the possible 1. boundaries between these 6 variants there are only two types of domain boundaries: (1. m1.0> boundaries C'/C, A'/A, and B'/B. (2) m1.0> boundaryies C'/A, C'/A', C'/B, C'/B', C/A, C/A', C/B, C/B', B'/A, B'/A', B/A, and B/A' .

关键词： domain domain boundary group theory transmission electron microscopy perovskite

Approaches to improving critical current density of YBCO superconducting thick films deposited by electrophoresis

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Science china({1.,Mechanics & Astronomy) 2004年第2期47卷 165-172页

作者： ZHU Yabin1.2, ZHOU Yueliang2, LIU Zhen2, wang Shufang2, CHEN Zhenghao2, L?Huibin2, YANG Guozhen2, XIAO Ling3, {1. Hongtao3, JIAO Yulei3 & ZHENG Minghui3 1. department of physics, College of Science, Beijing Jiaotong university, Beijing 1.0044, china 2. Laboratory of Optical physics, Institute of physics and Center for Condensed Matter physics, Chinese Academy of Sciences, Beijing 1.0080, china 3. General Research Institute for Nonferrous Metals, Beijing 1.0088, china Correspondence should be addressed to Zhu Yabin (email: ybzhu@***) department of {1. College of Science Beijing Jiaotong University Beijing China Laboratory of Optical physics Institute of physics and Center for Condensed Matter physics Chinese Academy of Sciences Beijing China General Research Institute for Nonferrous Metals Beijing China

Fabrication of YBCO superconducting thick films by electrophoresis has been widely reported. However, the value of critical current density (J c) is far from what the practical application requires. The superconducting thick films are obtained using top-seeded melt growth method with different proportional Y2BaCuO5 (Y21.) addition. High-pressure oxygen has been used in the annealing process to improve the uniformity of the oxygen content in the superconducting thick films. When 40mol% Y21. powder is added to the YBa2Cu3O7–5 (Y1.3) powder,J c for the superconducting thick film by approaches described above reaches 7.008×1.3 A/cm2 (77 K, 0 T), which is greater than the value ever reported.

关键词： YBCO thick films, electrophoretic deposition, melt-textured.

Low-temperature-pyrolysis preparation of nanostructured graphite towards rapid potassium storage with high initial Coulombic efficiency

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Nano Research 2024年第6期17卷 5138-5147页

作者： Jingke ren Boyu Xing Wen Luo Binyang Luo Xinfei Wu Xin Yan Wencong Feng Feiyue {1. Chaojie Cheng Liqiang Mai State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China department of {1. School of ScienceWuhan University of TechnologyWuhan 430070China

Industrially prepared artificial graphite(AG)is attractive for potassium-ion batteries(PIBs),but its rate performance is poor and the production process is energy intensive,so developing an efficient strategy to produce novel graphite with low energy consumption and high performance is economically ***,a nanostructured graphite composed of multi-walled carbon nanotubes(MWCNTs)and graphite shells was prepared by one-pot method through low-temperature pyrolysis of iron-based metal-organic framework(MOF)and carbon *** high graphitization degree of nanostructured graphite makes the initial Coulombic efficiency(ICE)exceed 80%,and the three-dimensional(3D)conductive network ensures a specific capacity of 234 mAh·g^(−1.after 1.00 cycles at a high current density of 500 mA·g^(−1..In addition,the typical graphite potassium storage mechanism is also demonstrated by in situ X-ray diffraction(XRD)and in situ Raman spectroscopy,and its practicality is also proved by the voltage of the full *** work provides a feasible way to optimize the practical production process of AG and expand its application in energy storage.

关键词： graphite anode potassium-ion batteries high graphitization degree low-temperature pyrolysis initial Coulombic efficiency

La_(2/3)Ca_(1.3)MnO_3薄膜的光致电阻率变化特性

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物理学报 2004年第2期53卷 587-591页

作者：汪世林陈长乐王跃龙金克新王永仓任韧宋宙模袁孝西北工业大学应用物理系西安710072 华中科技大学武汉430074

射频磁控溅射法制备了La2 3Ca1. 3MnO3纳米薄膜 (LCMO) .该薄膜发生FM PM相变的转变点温度为Tc≈ 30 8K(近似为电阻峰值温度Tp) ;在不同温度下的光电导性质实验表明所制备的LCMO薄膜在连续激光作用时低温段(T 0 ,并在R T曲线拐点附近... 详细信息

射频磁控溅射法制备了La2 3Ca1. 3MnO3纳米薄膜 (LCMO) .该薄膜发生FM PM相变的转变点温度为Tc≈ 30 8K(近似为电阻峰值温度Tp) ;在不同温度下的光电导性质实验表明所制备的LCMO薄膜在连续激光作用时低温段(T 0 ,并在R T曲线拐点附近取得极大值 ,(ΔR R) max=4 3 5 % ;当T>Tc 时 ,ΔR R <0 ,即光电导效应 .调制激光脉冲光响应实验发现 ,光致信号强度和温度及偏置电流之间存在非线性关系 :光致电阻率增大信号极大值为偏置电流的二次函数 ,而极大值对应的温度和偏置电流成线性关系 ,同时 ,光响应有一个截止温度 ,并且存在最佳光响应偏置电流和温度条件 .

关键词：钙钛矿薄膜光响应电子自旋小极化子光致电阻率射频磁控溅射法相变转变点温度

Fabrication of hexagonal gallium nitride films on silicon (1.1. substrates

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Rare Metals 2003年第3期22卷 221-225页

作者： YANGLi XUEChengshan wangCuimei LIHuaixiang {1.Yuwen ChemistryFunctionMaterialsLab InstituteofSemiconductorsShandongNormalUniversityJinan250014China physicsDe0artment ShandongNormalUniversityJinan250014China InspectionInstituteforElectronicProductsofShandong Jinan250000China

Hexagonal gallium nitride films were successfully fabricated throughammoniating Ga_2O_3 films deposited on silicon (1.1. substrates by electrophoresis. The structure,composition, and surface morphology of the formed films were characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmissionelectron microscopy (TEM). The measurement results reveal that the polycrystalline GaN films withhexagonal wurtzite structure were successfully grown on the silicon (1.1. substrates. Preliminaryresults suggest that varying the ammoniating temperature has obvious effect on the quality of theGaN films formed with this method.

关键词： semiconductor materials GaN films electrophoresis Ga_2O_3