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Simulation of magnetization process and Faraday effect of magnetic bilayer films

Chinese Physics B 2024年第9期33卷 590-597页

作者： Sheng Gao An Du Lei Zhang Tian-Guang Li da-cheng ma Department of Basic and General Studies Shenyang Institute of Science and TechnologyShenyang 110167China College of Science Northeastern UniversityShenyang 110819China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern UniversityShenyang 110819China Office of Academic Research Shenyang Institute of Science and TechnologyShenyang 110167China State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy ofSciencesShenyang 110016China Institutes for Robotics and Intelligent manufacturing Chinese Academy of SciencesShenyang110016China

We described ferromagnetic film and bilayer films composed of two ferromagnetic layers coupled through antiferromagnetic interfacial interaction by classical Heisenberg model and simulated their magnetization state,magnetic permeability,and Faraday effect at zero and finite temperature by using the Landau–Lifshitz–Gilbert(LLG)*** results indicate that in a microwave field with positive circular polarization,the ferromagnetic film has one resonance peak while the bilayer film has two resonance ***,the resonance peak disappears in ferromagnetic film,and only one resonance peak emerges in bilayer film in the negative circularly polarized microwave *** the microwave field’s frequency exceeds the film’s resonance frequency,the Faraday rotation angle of the ferromagnetic film is the greatest,and it decreases when the thickness of the two halves of the bilayer is *** the microwave field’s frequency remains constant,the Faraday rotation angle fluctuates with temperature in the same manner as spontaneous magnetization *** a DC magnetic field is applied in the direction of the anisotropic axis of the film,the Faraday rotation angle varies with the DC magnetic field and shows a similar shape of the hysteresis loop.

关键词： magnetic bilayer films magnetic permeability hysteresis loop Faraday effect Landau–Lifshitz– Gilbert (LLG) equation

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Existence of long-range magnetic order in Heisenberg spin nanoribbons with edge modification

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Communications in Theoretical Physics 2024年第7期76卷 134-144页

作者： da-cheng ma Ling-yi Cui Chu-xiao Sun Xiao-dan Chi Zheng-Nan XianYu An Du College of Science Northeastern UniversityShenyang 110819China Department of Basic Science Dalian Naval AcademyDalian 116018China Department of Physics College of SciencesShenyang University of Chemical TechnologyShenyang 110142China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern UniversityChina Key Laboratory of data Analytics and Optimization for Smart Industry(Northeastern University) Ministry of EducationChina

Long-range magnetic order appears on a side decorated Heisenberg spin nanoribbon at nonzero temperature,although no spontaneous magnetization exists in a one-or two-dimensional isotropic Heisenberg model at any nonzero temperature according to the Mermin-Wagner *** use of the spin Green's function method,we calculated the magnetizations of Heisenberg nanoribbons decorated by side spins with single-ion anisotropy and found that the system exhibits a nonzero transition temperature,whether the decorated edge spins of the system link together or separate from each *** the width of the nanoribbon achieves infinite limit,the transition temperatures of the system tend to the same finite constant eventually whether one edge or both edges are decorated by side spins in the *** results reveal that the magnetism of a low-dimensional spin system is different from that of a threedimensional spin *** the single-ion anisotropy of edge spins in a Heisenberg spin nanoribbon can be modulated by an electric field experimentally,various useful long-range magnetic orders of the system can be *** work can provide a detailed theoretical basis for designing and fabricating next-generation low-dimensional magnetic random-access memory.

关键词： Nanoribbon magnetic anisotropy long-range magnetic order Heisenberg model transition temperature

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A new tetrastilbene from Caragana sinica

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Chinese Chemical Letters 2008年第6期19卷 711-715页

作者： Ke Jun cheng da You ma Guo Xun Yang Chang Qi Hu Department of Chemistry of Natural Products Fudan University Shanghai 200032 China

A new tetrastilbene named carasinol D （1） was isolated from the roots of Caragana sinica. Its structure was elucidated by spectroscopic analysis. Compound 1 was obtained from carasinol B （2） by an acid-catalyzed c... 详细信息

关键词： Caragana sinica Stilbenoids Carasinol D Carasinol B

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Elastic wave insulation and propagation control based on the programmable curved-beam periodic structure

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Applied mathematics and Mechanics(English Edition) 2024年第10期45卷 1791-1806页

作者： Jiajia maO Hong cheng Tianxue ma Beijing Key Laboratory of Nonlinear Vibrations and Strength of Mechanical Structures Department of Mechanics School of Mathematics Statistics and MechanicsBeijing University of Technology Department of Mechanics School of Physical Science and EngineeringBeijing Jiaotong University

Curved-beams can be used to design modular multistable metamaterials(MMMs) with reprogrammable material properties, i.e., programmable curved-beam periodic structure(PCBPS), which is promising for controlling the elastic wave *** PCBPS is theoretically equivalent to a spring-oscillator system to investigate the mechanism of bandgap, analyze the wave propagation mechanisms, and further form its geometrical and physical criteria for tuning the elastic wave propagation. With the equivalent model, we calculate the analytical solutions of the dispersion relations to demonstrate its adjustability, and investigate the wave propagation characteristics through the PCBPS. To validate the equivalent system, the finite element method(FEM) is *** is revealed that the bandgaps of the PCBPS can be turned on-and-off and shifted by varying its physical and geometrical characteristics. The findings are highly promising for advancing the practical application of periodic structures in wave insulation and propagation control.

关键词： 74J05 74Q10 curved-beam based periodic structure dispersion relation equivalent stiffness O326 spring-oscillator system wave propagation

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Aero-structural design of joined-wing aircraft based on high-fidelity model

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Chinese Journal of Aeronautics 2024年第4期37卷 363-377页

作者： cheng HE Fengjiang ZHAN Luchuang ma Gang CHEN Jianying ma Unmanned Air Vehicle Research Institute Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Advanced Technology for Small and Medium-sized UAV Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016China Aerospace System Engineering Shanghai Shanghai 201108China

The joined-wing configuration reduces induced drag and structural weight by connecting the rear wing to the front *** addition,the rear wing can replace the role of the horizontal tail of a conventional aircraft,thus eliminating the aerodynamic drag and weight associated with the horizontal *** particular shape creates a highly coupled relationship between aerodynamics and structure,which must be fully considered during the overall design process to enhance aircraft *** this research,an aero-structural design model of the joined-wing aircraft is constructed based on high-fidelity computational fluid dynamics and structural finite element *** model is able to obtain accurate aerodynamic loads for the non-planar wing and to simulate the statically indeterminate structure of the closed wing *** influence of the joined-wing shape parameters on the aerodynamic and structural disciplines,as well as the influence of geometric nonlinear characteristics,deformation constraints and buckling constraints on the structural weight are all taken into *** model is applied to complete the aero-structural design optimization of a high-altitude long-endurance joined-wing aircraft,and wind tunnel tests are *** test results verify the credibility of the design model proposed and the validity of the design environment.

关键词： Joined-wing configuration Aircraft design Aero-structural design Finite element Wind tunnel test

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Analysis of piezoelectric semiconductor fibers under gradient temperature changes

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Applied mathematics and Mechanics(English Edition) 2024年第2期45卷 311-320页

作者： Shuangpeng LI Ruoran cheng Nannan ma Chunli ZHANG Department of Engineering Mechanics Zhejiang UniversityHangzhou 310027China

Piezoelectric semiconductors(PSs)possess both semiconducting properties and piezoelectric coupling effects,making them optimal building blocks for semiconductor *** fiber-like structures have wide applications in multi-functional semiconductor *** this paper,a one-dimensional(1D)theoretical model is established to describe the piezotronic responses of a PS fiber under gradient temperature *** theoretical model aims to explain the mechanism behind the resistance change caused by such gradient temperature *** results demonstrate that a gradient temperature change significantly affects the physical fields within the PS fiber,and can induce changes in its surface *** provides important theoretical guidance on the development of piezotronic devices that are sensitive to temperature effects.

关键词： piezoelectric semiconductor(PS)fiber one-dimensional(1D)model piezotronic effect gradient temperature change

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“Blocking and rebalance” mechanism-guided design strategies of bimetallic doped 2D a-phosphorus carbide as efficient catalysts for N2 electroreduction

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Journal of Energy Chemistry 2024年第10期97卷 68-78页

作者： cheng He Jianglong ma Shen Xi Wenxue Zhang State Key Laboratory for Mechanical Behavior of materials School of Materials Science and Engineering Xi'an Jiaotong University School of materials Science and Engineering Chang'an University

Compared to single atom catalysts（SACs）,the introduction of dual atom catalysts（daCs） has a significantly positive effect on improving the efficiency in the electrocatalytic nitrogen reduction reaction（NRR） which provides an environmental alternative to the Haber-Bosch ***,the research on the mechanism and strategy of designing bimetallic combinations for better performance is still in its early ***,based on "blocking and rebalance" mechanism,45 combinations of bimetallic pair doped α-phosphorus carbide（TmaTMB@PC） are investigated as efficient NRR catalysts through density functional theory and machine learning *** a multi-step screening,the combinations of TiV,TiFe,MnMo,and FeW exhibit highly efficient catalytic performance with significantly lower limiting potentials（-0.17,-0.18,-0.14,and-0.30 V,respectively）.Excitingly,the limiting potential for CrMo and CrW combinations is 0 V,which are considered to be extremely suitable for the NRR *** mechanism of "blocking and rebalance" is revealed by the exploration of charge transfer for phosphorus atoms in electron blocking ***,the descriptor φ is proposed with machine learning,which provides design strategies and accurate prediction for finding efficient *** work not only offers promising catalysts TmaTMB@PC for NRR process but also provides design strategies by presenting the descriptor φ.

关键词： 2D α-phosphorus carbide daCs Inherent attributes machine learning Nitrogen reduction reaction

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A new method for evaluating wedges of steel plates and strips

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Journal of Iron and Steel Research International 2024年第7期31卷 1719-1735页

作者： Xiao-bao ma Xiao-xin ma Tao Wang Zhong-kai Ren Yu-cheng Ren College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan 030024ShanxiChina Ministry of Education Engineering Research Center of Advanced Metal Composite Forming Technology and Equipment Taiyuan University of TechnologyTaiyuan 030024ShanxiChina National Key Laboratory of Metal Forming Technology and Heavy Equipment Taiyuan University of TechnologyTaiyuan 030024ShanxiChina China National Heavy machinery Research Institute Co. Ltd.Xi'an 710018ShaanxiChina Faculty of Mechanical Engineering Hebei University of ArchitectureZhangjiakou 075000HebeiChina

To overcome the inaccuracy problem of the traditional wedge evaluation of steel plates and strips caused by the ran-domness of the thicknesses of two local points and improve the reliability of the wedge index,the double-centroid method for the wedge evaluation was proposed,and a model based on the centroid theory was ***,an integral model for the discrete thickness values of the cross-section profiles was *** discussion focused on the distinct characteristics of the two-point method,asymmetric method,and double-centroid method in evaluating the asymmetric distribution of *** three methods were employed to evaluate the wedge values of both the theoretical and measured cross-sections of steel plates and strips,and the accuracies of three wedge evaluation models were analyzed and *** results showed that the double-centroid method objectively reflects the degree and variation characteristics of the wedge values of the cross-sections of steel plates and strips,and this method is feasible,reliable,and outstanding.

关键词： Steel plate and strip Wedge Two-point method Double-centroid method Reliability

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Impact of Polymer matrix on Polymer Mechanochromism from Excited State Intramolecular Proton Transfer

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Chinese Journal of Chemistry 2024年第6期42卷 611-616页

作者： Yu Wu Xin cheng Huan Hu Shui Hu Zhimin ma Zhiyong ma Beijing Advanced Innovation Center for Soft matter Science and Engineering Beijing State Key Laboratory of Organic-Inorganic CompositesCollege of Chemical EngineeringBeijing University of Chemical TechnologyBeijing100029 China Center of Advanced Elastomer materials College of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing100029 China College of Engineering Peking UniversityBeijing100871 China

Mechanochromic polymers based on non-covalent changes have attracted much attention ***,we report the impact of inter/intramolecular hydrogen bonds on polymer mechanochromism from the excited state intramolecular proton transfer (ESIPT) ***-NH2-OH and PhMz=2A are designed and obtained by simple and high-yield synthesis,and are connected into polyurethane and poly(methyl acrylate-co-2-ethylhexyl acrylate),*** the initial state,the PhMz-NH2-OH@PU sample shows blue fluorescence from the excited enol form (E*) excitons,owing to intermolecular hydrogen bonds that interrupt the ESIPT reactions but the PhMz=2A@Pma-2-EA sample expresses cyan fluorescence belonging to the excited keto form (K*) emission,implying that the intramolecular hydrogen bonds ***,under stretching,external force can tune the emission of the PhMz=2A@Pma-2-EA sample from K* to E* *** external force can putatively still promote a bond rotation,ESIPT reactions remain equivalently interrupted in both the relaxed and stressed states in a hydrogen-bond donating *** calculation confirms the force-induced increase in dihedral angle for the transition of ESIPT-on/***,PhMz-NH2-OH@PU and PhMz=2A@Pma-2-EA showed disparate initial ESIPT states and further different responses/sensitivity to *** study reports a novel and efficient strategy for enriching mechanochromic investigation and extending the applications of ESIPT reactions.

关键词： Polymer mechanochromism Excited state intramolecular proton transfer Hydrogen bonding Supramolecular chemistry Elastomers

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Diversity and ecological assembly process of aerobic anoxygenic phototrophic bacteria in a low irradiation area,Three Gorges Reservoir

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Journal of Environmental Sciences 2024年第9期143卷 116-125页

作者： Lixin Huo Anran ma Hong Liu Xingzu Wang cheng Song Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714China Chongqing School University of Chinese Academy of SciencesCollege of Resources and EnvironmentChongqing 400714China Key Laboratory of Reservoir Aquatic Environment Chinese Academy of SciencesChongqing 400714China University of Chinese Academy of Sciences Beijing 100049China

Aerobic anoxygenic phototrophic bacteria(AAPB)are significant bacterial groups in aquatic ecosystems,known for their rapid growth and photoheterotrophic ***,the distribution and ecological assembly process of AAPB in low irradiation freshwater basins remain unclear,warranting further *** this study,we present the diversity,abundance,spatial variations,ecological process,and community interaction of AAPB in sediment of Three Gorges Reservoir(TGR)under low *** findings demonstrate the dominant genera of AAPB community that exist in the TGR area also are appeared in different waters,with some regional ***,the concentration of pufM gene,an indicator for AAPB,maintains a consistently high numerical level ranging from(2.21±0.44)×10^(4)to(9.98±0.30)×10^(7)gene copies/*** solar irradiation is suggested as the major factor affecting AAPB,it remains unclear whether and how AAPB differ between regions due to varying solar irradiation *** results show spatial differences between total bacteria and AAPB communities,with significant differences observed only in *** and environmental factor contributed less than 10%to the spatial difference of community,with sediment type and environmental factors being the key factors influencing microbial community *** stochastic process plays a dominant role in the aggregation and replacement of AAPB communities,among which the most contribution is dispersal *** AAPB network,Yoonia and Gemmobacter are the hubs for *** results valuable insights into the AAPB communities in TGR with low irradiation.

关键词： Three Gorges Reservoir(TGR) Aerobic anoxygenic phototrophic bacteria(AAPB) Bacterial community Null model Community assembly

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