检索结果-南通市图书馆

Periodic Instanton Calculations of Quantum-Classical Transitions in Spin Systems

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 1998年第9期15卷 683-685页

作者： ZHANG Yun-bo NIE Yi-hang kou su-peng WANG Xiao-bing LIANG Jiu-qing PU Fu-ke Institute of Physics and Center for Condensed Matter Physics Chinese Academy of SciencesBeijing 100080 Department of Physics Shanxi UniversityTaiyuan 030006 Center for Advanced Study Tsinghua UniversityBeijing 100084 Department of Physics Guangzhou Normal CollegeGuangzhou 510400

The quantum-classical transitions of the escape rates in the molecular magnet Mnl2Ac and a biaxial anisotropic ferromagnetic spin model are investigated by applying the periodic instanton *** effective free energies are expanded around the top of the potential barrier in analogy to the Landau theory of phase *** show that the first-order transitions occur below the critical external magnetic field h_(x)=1/4 for Mnl2Ac and beyond the critical anisotropy constant ratioλ=1/2 for the biaxial ferromagnetic grains,which is in good agreement with earlier studies.

关键词： transitions ferromagnetic Transition

FK506 contributes to peripheral nerve regeneration by inhibiting neuroinflammatory responses and promoting neuron survival

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第7期20卷 2108-2115页

作者： Yuhui kou Zongxue Jin Yusong Yuan Bo Ma Wenyong Xie Na Han Department of Trauma and Orthopedics Peking University People’s HospitalBeijingChina National Center for Trauma Medicine Peking University People’s HospitalBeijingChina Key Laboratory of Trauma and Neural Regeneration(Peking University) Ministry of EducationBeijingChina Trauma Medicine Center Peking University People’s HospitalBeijingChina Department of Orthopedics China-Japan Friendship HospitalBeijingChina

FK506(Tacrolimus)is a systemic immunosuppressant approved by the *** and Drug ***506 has been shown to promote peripheral nerve regeneration,however,its precise mechanism of action and its pathways remain *** this study,we established a rat model of sciatic nerve injury and found that FK506 improved the morphology of the injured sciatic nerve,increased the numbers of motor and sensory neurons,reduced inflammatory responses,markedly improved the conduction function of the injured nerve,and promoted motor function *** findings suggest that FK506 promotes peripheral nerve structure recovery and functional regeneration by reducing the intensity of inflammation after neuronal injury and increasing the number of surviving neurons.

关键词： FK506 inflammation motor neurons nerve regeneration neuron peripheral nerve injury sensory neurons

MPC-based Torque Distribution for Planar Motion of Four-wheel Independently Driven Electric Vehicles:Considering Motor Models and Iron Losses

在线全文

学校读者我要写书评

暂无评论

CES Transactions on Electrical Machines and Systems 2023年第1期7卷 45-53页

作者： Yiyan su Deliang Liang peng kou the State Key Laboratory of Electrical Insulation and Power Equipment School of Electrical EngineeringXi'an Jiaotong UniversityXi’an710049China IEEE

The most critical obstacle for four-wheel independently driven electric vehicles(4WID-EVs)is the driving *** the actuators of 4WID-EVs,motors account for its major power *** this sense,by properly distributing torques to minimize the power consumption,the driving range of 4WID-EV can be effectively *** paper proposes a model predictive control(MPC)-based torque distribution scheme,which minimizes the power consumption of 4WID-EVs while guaranteeing its tracking performance of planar *** incorporating the motor model considering iron losses,the optimal torque distribution can be achieved without an additional torque ***,for this reason,the proposed control scheme is computationally efficient,since the power consumption term to be optimized,which is expressed as the product of the motor voltages and currents,is much simpler than that derived from the efficiency *** reasonable simplification and linearization,the MPC problem is converted to a quadratic programming problem,which can be solved *** simulation results in MATLAB and CarSim co-simulation environments demonstrate that the proposed scheme effectively reduces power consumption with guaranteed tracking performance.

关键词： four-wheel independently driven electric vehicles Model predictive control Motor models Iron losses

Non-Hermitian Ising model at finite temperature

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2023年第4期75卷 123-130页

作者： Qian Du Kui Cao su-peng kou Center for Advanced Quantum Studies Department of PhysicsBeijing Normal UniversityBeijing 100875China

As a very simple model,the Ising model plays an important role in statistical *** the paper,with the help of quantum Liouvillian statistical theory,we study the one-dimensional nonHermitian Ising model at finite temperature and give its analytical *** find that the nonHermitian Ising model shows quite different properties from those of its Hermitian *** example,the‘pseudo-phase transition’is explored between the‘topological’phase and the‘nontopological’phase,at which the Liouvillian energy gap is closed rather than the usual energy *** particular,we point out that the one-dimensional non-Hermitian Ising model at finite temperature can be equivalent to an effective anisotropic XY model in the transverse *** work will help people understand quantum statistical properties of non-Hermitian systems at finite temperatures.

关键词： non-Hermitian quantum system Ising model quantum statistical mechanics thermodynamics

16.48% Efficient solution-processed CIGS solar cells with crystal growth and defects engineering enabled by Ag doping strategy

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2025年第1期100卷 59-65页

作者： Mengyu Xu Shaocong Yan Ting Liang Jia Jia Shengjie Yuan Dongxing kou Zhengji Zhou Wenhui Zhou Yafang Qi Yuena Meng Litao Han Sixin Wu Key Laboratory for Special Functional Materials of MOE National & Local Joint Engineering Research Centre for High-efficiency Display and Lighting Technology School of Nanoscience and Materials Engineering Henan University

Solution-processed Cu（In,Ga）Se2（CIGS） solar cells suffer from serious carrier recombination and power conversion efficiency（PCE） loss because of the poor film properties and easy formation of ***, we propose Ag&Se co-selenization strategy to enhance the crystallization and passivate harmful defects of the CIGS films. The formation of Ag-Se phase during the selenization process enables the formation of large grains and suppresses the deep level defects. It is found that Ag doping can enlarge the depletion region width, lower the Urbach energy and prolong the carrier lifetime. As a result, a champion solution-processed CIGS solar cell presents a high efficiency of 16.48% with the highly improved opencircuit voltage（VOC） of 662 m V and fill factor（FF） of 75.8%. This work provides an efficient strategy to prepare high quality solution-processed CIGS films for high-performance CIGS solar cells.

关键词： Cell engineering

Biorthogonal quantum criticality in non-Hermitian many-body systems

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Frontiers of physics 2022年第3期17卷 53-61页

作者： Gaoyong sun Jia-Chen Tang su-peng kou College of Science Nanjing University of Aeronautics and AstronauticsNanjing 211106China Key Laboratory of Aerospace Information Materials and Physics(Nanjing University of Aeronautics and Astronautics) MIITNanjing 211106China Center for Advanced Quantum Studies Department of PhysicsBeijing Normal UniversityBeijing 100875China

We develop the perturbation theory of the fidelity susceptibility in biorthogonal bases for arbitrary interacting non-Hermitian many-body systems with real eigenvalues. The quantum criticality in the non-Hermitian transverse field Ising chain is investigated by the second derivative of the ground-state energy and the ground-state fidelity susceptibility. We show that the system undergoes a second-order phase transition with the Ising universal class by numerically computing the critical points and the critical exponents from the finite-size scaling theory. Interestingly, our results indicate that the biorthogonal quantum phase transitions are described by the biorthogonal fidelity susceptibility instead of the conventional fidelity susceptibility.

关键词： biorthogonal quantum criticality non-Hermitian systems fidelity susceptibility

Quantum critical duality in two-dimensional Dirac semimetals

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2019年第1期28卷 584-593页

作者： Jiang Zhou Ya-Jie Wu su-peng kou Department of Physics Guizhou University School of Science Xi’an Technological University Department of Physics Beijing Normal University

Quantum criticality is closely related to the existence of two phases with unrelated symmetry breaking. In this paper,we study Néel and Kekulé valence bond state(VBS) quantum criticality in Dirac semimetals with four-fermion *** results show that all possible dynamical masses yield the same critical coupling, which exhibits the phenomenon that all possible phases meet at a multicritical point(e.g., a tricritical point for the Néel, Kekulé-VBS and semimetallic phases).In terms of the well-established Wess–Zumino–Witten field theory, we investigate the typical criticality for the transition between Néel and Kekulé-VBS phases, and the compatible Néel–Kekulé-VBS mass matrices imply the existence of a nonLandau transition between the Néel and Kekulé-VBS phases. We show the existence of mutual duality in the defect-driven Néel–Kekulé-VBS transition near the non-Landau critical point and find that this mutual duality results from the presence of a mutual Chern–Simons term. We also study the mutual duality based on dual topological excitations.

关键词： quantum criticality duality semimetal–insulator transition spin–charge separation

Bogoliubov excitations in a Bose–Hubbard model on a hyperhoneycomb lattice

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2018年第5期27卷 108-114页

作者： Wen-yan Zhou Ya-jie Wu su-peng kou Department of Physics Beijing Normal UniversityBeijing 100875China School of Science Xi'an Technological UniversityXi'an 710032China

We study the topological properties of Bogoliubov excitation modes in a Bose–Hubbard model of three-dimensional(3 D)hyperhoneycomb *** the non-interacting case,there exist nodal loop excitations in the Bloch *** the on-site repulsive interaction increases,the system is first driven into the superfluid phase and then into the Mott-insulator *** both phases,the excitation bands exhibit robust nodal-loop structures and bosonic surface *** a topology point of view,these nodal-loop excitation modes may be viewed as a permanent fingerprint left in the Bloch bands.

关键词： hyperhoneycomb lattice Mott-superfluid transition Bogoliubov excitations nodal-loop

State-Dependent Topological Invariants and Anomalous Bulk-Boundary Correspondence in Non-Hermitian Topological Systems with Generalized Inversion Symmetry

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2020年第11期37卷 87-92页

作者： Xiao-Ran Wang Cui-Xian Guo Qian Du su-peng kou Center for Advanced Quantum Studies Department of PhysicsBeijing Normal UniversityBeijing 100875China

Breakdown of bulk-boundary correspondence in non-Hermitian(NH)topological systems with generalized inversion symmetries is a controversial *** non-Bloch topological invariants determine the existence of edge states,but fail to describe the number and distribution of defective edge states in non-Hermitian topological *** state-dependent topological invariants,instead of a global topological invariant,are developed to accurately characterize the bulk-boundary correspondence of the NH systems,which is very different from their Hermitian *** the same time,we obtain the accurate phase diagram of the one-dimensional non-Hermitian su–Schrieffer–Heeger model with a generalized inversion symmetry from the state-dependent topological ***,these results will be helpful for understanding the exotic topological properties of various non-Hermitian systems.

关键词： topological invariants correspondence