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Effect of cerium on microstructure,texture and properties of ultrahigh-purity copper

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Journal of Rare Earths 2024年第1期42卷 220-227,I0008页

作者： Yunxiao Hua Haitao Liu Kexing Song Jiangwei Wang Yin'gang guo Jing tian Huiwen guo Provincial and Ministerial Co-construction of Collaborative Innovation Center for Non-ferrous Metal New Materials and Advanced Processing Technology School of Materials Science and EngineeringHenan University of Science and TechnologyLuoyang471023China Henan Academy of Sciences Zhengzhou450000China Center of Electron Microscopy and State Key Laboratory of Silicon Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou310027China Henan Zhongyuan Gold Smelter Co. Ltd.Sanmenxia472100China Chinalco Luoyang Copper Processing Co. Ltd.Luoyang471039China

The effects of Ce addition(310 ppm and 1500 ppm)on the microstructure,texture and properties of ultrahigh-purity copper(99.99999%)were systematically studied using scanning electron microscopy(SEM),transmission electron microscopy(TEM)and electron backscattered diffraction(EBSD)analyses,combined with the microhardness and conductivity *** the microstructure of the as-cast and as-extruded samples,the addition of Ce refines the grain size of the ultrahigh-purity copper and the refinement effect of 310Ce alloy is greater than that of 1500Ce *** is due to the stronger compone nt supercooling and the accele rated recrystallization caused by lower Ce co *** addition,Ce can react with Cu to form the Cu-Ce eutectic phases,which are deformable during the hot ***,the added Ce can weaken the texture,showing a variation of brass recrystallization(BR),rotated cube,copper and S texture components,which depends on the recrystallization,the particle stimulated nucleation(PSN)as well as the stacking fault energy(SFE).Most remarkably,the introduction of Ce enhances the hardness of the ultrahigh-purity copper without obviously reducing its *** major{111}orientations and the stress distributions are responsible for such a superior conductivity of the Ce-containing alloys.

关键词： Ce addition Grain refinement Texture Conductivity Ultrahigh-purity copper Rare earths

Research on human gait sensing based on triboelectric nanogenerator

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Nanotechnology and Precision Engineering 2024年第2期7卷 32-40页

作者： gang Yang Lifang Wang Jiayun tian School of Communication and Information Engineering Xi’an University of Posts and TelecommunicationsXi’an 710121China

To address the problem of frequent battery replacement for wearable sensors applied to fall detection among the elderly,a portable and lowcost triboelectric nanogenerator(TENG)-based self-powered sensor for human gait monitoring is *** main fabrication materials of the TENG are polytetrafluoroethylene(PTFE)film,aluminum(Al)foil,and polyimide(PI)film,where PTFE and Al are the friction layer materials and the PI film is used to improve the output *** the ability of TENGs to monitor changes in environmental conditions,a self-powered sensor based on the TENG is placed in an insole to collect gait *** a TENG does not require a power source to convert physical and mechanical signals into electrical signals,the electrical signals can be used as sensing signals to be analyzed by a computer to recognize daily human activities and fall *** results show that the accuracy of the TENG-based sensor for recognizing human gait is 97.2%,demonstrating superior sensing performance and providing valuable insights for future monitoring of fall events in the elderly population.

关键词： Triboelectric nanogenerator Sensor Gait monitoring

Electrochemical anodic oxidation assisted fabrication of memristors

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International Journal of Extreme Manufacturing 2024年第3期6卷 250-272页

作者： Shuai-Bin Hua tian Jin Xin guo School of Materials Science and Engineering State Key Laboratory of Material Processing and Die&Mould TechnologyHuazhong University of Science and TechnologyWuhan 430074People’s Republic of China

Owing to the advantages of simple structure,low power consumption and high-density integration,memristors or memristive devices are attracting increasing attention in the fields such as next generation non-volatile memories,neuromorphic computation and data ***,the deposition of memristive films often requires expensive equipment,strict vacuum conditions,high energy consumption,and extended processing *** contrast,electrochemical anodizing can produce metal oxide films quickly(e.g.10 s) under ambient *** means of the anodizing technique,oxide films,oxide nanotubes,nanowires and nanodots can be fabricated to prepare *** film thickness,nanostructures,defect concentrations,etc,can be varied to regulate device performances by adjusting oxidation parameters such as voltage,current and *** memristors fabricated by the anodic oxidation technique can achieve high device consistency,low variation,and ultrahigh yield *** article provides a comprehensive review of the research progress in the field of anodic oxidation assisted fabrication of ***,the principle of anodic oxidation is introduced;then,different types of memristors produced by anodic oxidation and their applications are presented;finally,features and challenges of anodic oxidation for memristor production are elaborated.

关键词： anodic oxidation anodized aluminium oxide memristor resistive switching electrical properties

General properties of the spectral form factor in open quantum systems

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Frontiers of physics 2024年第3期19卷 229-237页

作者： Yi-Neng Zhou tian-gang Zhou Pengfei Zhang Institute for Advanced Study Tsinghua UniversityBeijing 100084China Department of Physics Fudan UniversityShanghai 200438China

The spectral form factor(SFF)can probe the eigenvalue statistic at different energy scales as its time variable *** closed quantum chaotic systems,the SFF exhibits a universal dip-ramp-plateau behavior,which reflects the spectrum rigidity of the *** this work,we explore the general properties of SFF in open quantum *** find that in open systems the SFF first decays exponentially,followed by a linear increase at some intermediate time scale,and finally decreases to a saturated plateau *** derive general relations between(i)the early-time decay exponent and Lindblad operators;(ii)the long-time plateau value and the number of steady *** also explain the effective field theory perspective of general *** verify our theoretical predictions by numerically simulating the Sachdev−Ye−Kitaev(SYK)model,random matrix theory(RMT),and the Bose−Hubbard model.

关键词： spectral form factor open quantum system quantum chaos

A thermodynamics-based three-scale constitutive model for partially saturated granular materials

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1813-1831页

作者： Jianqiu tian Enlong Liu Yuancheng guo State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu610065China School of Geoscience and Technology Southwest Petroleum UniversityChengdu610500China College of Civil Engineering Zhengzhou UniversityZhengzhou450001China

A three-scale constitutive model for unsaturated granular materials based on thermodynamic theory is *** three-scale yield locus,derived from the explicit yield criterion for solid matrix,is developed from a series of discrete interparticle contact *** three-scale yield locus is sensitive to porosity changes;therefore,it is reinterpreted as a corresponding constitutive model without phenomenological ***,a water retention curve is proposed based on special pore morphology and experimental *** features of the partially saturated granular materials are well captured by the *** wetting and isotropic compression,volumetric compaction occurs,and the degree of saturation ***,the higher the matric suction,the greater the strength,and the smaller the volumetric *** with the phenomenological Barcelona basic model,the proposed three-scale constitutive model has fewer parameters;virtually all parameters have clear physical meanings.

关键词： Unsaturated granular material Unsaturated porous material Geomaterials Multi-scale constitutive model Water retention curve Plasticity

Preface of the Special Issue on Symplectic Geometry and Mathematical Physics

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Acta Mathematica Sinica,English Series 2024年第1期40卷 1-2页

作者： Huijun Fan Xiaobo Liu gang tian Peking University BeijingChina

Symplectic geometry is a branch of differential geometry and differential topology and has its origins in the Hamiltonian formulation of classical *** the last few decades,symplectic geometry has experienced enormous progress and has had interactions with many other branches of mathematics,including enumerative geometry,low-dimensional topology,mathematical physics,Hamiltonian dynamics,integrable systems etc..

关键词： geometry topology Hamiltonian

Deterministic wave prediction model for irregular long-crested waves with Recurrent Neural Network

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Journal of Ocean Engineering and Science 2024年第3期9卷 251-263页

作者： Yue Liu Xiantao Zhang gang Chen Qing Dong Xiaoxian guo Xinliang tian Wenyue Lu Tao Peng State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University(SJTU)Shanghai 200240China SJTU Yazhou Bay Institute of Deepsea Technology SanyaHainan572000China

Real-time predicting of stochastic waves is crucial in marine *** this paper,a deep learning wave prediction(Deep-WP)model based on the‘probabilistic’strategy is designed for the short-term prediction of stochastic *** Deep-WP model employs the long short-term memory(LSTM)unit to collect pertinent information from the wave elevation time *** irregular long-crested waves generated in the deepwater offshore basin at Shanghai Jiao Tong University are used to validate and optimize the Deep-WP *** the prediction duration is 1.92s,2.56s,and,3.84s,respectively,the predicted results are almost identical with the ground *** the prediction duration is increased to 7.68s or 15.36s,the Deep-WP model’s error increases,but it still maintains a high level of accuracy during the first few *** introduction of covariates will improve the Deep-WP model’s performance,with the absolute position and timestamp being particularly advantageous for wave ***,the Deep-WP model is applicable to predict waves with different energy *** proposed Deep-WP model shows a feasible ability to predict nonlinear stochastic waves in real-time.

关键词： Real-time wave prediction Probability LSTM Covariate

A Fractional-Order Ultra-Local Model-Based Adaptive Neural Network Sliding Mode Control of n-DOF Upper-Limb Exoskeleton With Input Deadzone

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 760-781页

作者： Dingxin He HaoPing Wang Yang tian Yida guo the School of Automation Nanjing University of Science and TechnologyNanjing 210094China IEEE Norinco Group Institute of Navigation and Control Technology Beijing 100089China

This paper proposes an adaptive neural network sliding mode control based on fractional-order ultra-local model for n-DOF upper-limb exoskeleton in presence of uncertainties,external disturbances and input *** the model complexity and input deadzone,a fractional-order ultra-local model is proposed to formulate the original dynamic system for simple controller ***,the control gain of ultra-local model is considered as a *** fractional-order sliding mode technique is designed to stabilize the closed-loop system,while fractional-order time-delay estimation is combined with neural network to estimate the lumped ***,a fractional-order ultra-local model-based neural network sliding mode controller(FO-NNSMC) is ***,to avoid disadvantageous effect of improper gain selection on the control performance,the control gain of ultra-local model is considered as an unknown ***,the Nussbaum technique is introduced into the FO-NNSMC to deal with the stability problem with unknown ***,a fractional-order ultra-local model-based adaptive neural network sliding mode controller(FO-ANNSMC) is ***,the stability analysis of the closed-loop system with the proposed method is presented by using the Lyapunov ***,with the co-simulations on virtual prototype of 7-DOF iReHave upper-limb exoskeleton and experiments on 2-DOF upper-limb exoskeleton,the obtained compared results illustrate the effectiveness and superiority of the proposed method.

关键词： Adaptive control input deadzone model-free control n-DOF upper-limb exoskeleton neural network

Utilizing N-hydroxy-9-octadecenamide as a collector in flotation separation of bastnaesite and fluorite

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Journal of Rare Earths 2024年第8期42卷 1620-1628,I0008页

作者： Zhihao guo Sultan Ahmed Khoso Mengjie tian Wei Sun School of Minerals Processing and Bioengineering Central South UniversityChangsha410083China State Key Laboratory of Mineral Processing Beijing102600China Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources Wuhan430081China Key Laboratoryof Hunan Province for Cleanand Efficient Utilization of Strategic Calcium-containing Mineral Resources Central South UniversityChangsha410083China Department of Mining Engineering Mehran University of Engineering&TechnologyJamshoro76062Pakistan

Bastnaesite((Ce,La,Pr,Nd)CO_(3)F) is a significant light rare earth mineral found in nature,known for its fine-grained *** is commonly employed for the recovery of fine-grained bastnaesite *** serve as an essential flotation reagent that enhance the surface hydrophobicity of target minerals.A novel collector,N-hydroxy-9-octadecenamide(N-OH-9-ODA),was synthesised in this study.N-OH-9-ODA exhibits superior selectivity compared to the traditional collector oleic acid in the flotation separation of bastnaesite and *** experimental and co mputational results indicate that N-OH-9-ODA exhibits superior selectivity due to its higher adsorption affinity for bastnaesite surface compared to fluorite *** zeta potential and the binding energies of the Ce 3d peaks in the X-ray photoelectron spectrum(XPS) of bastnaesite surface exhibit significant ***,fluorite surface demonstrates minimal alterations in its zeta potential and the binding energies of the Ca 2p peaks in its XPS after its interaction with N-OH-9-ODA.

关键词： Bastnaesite Collector Hydroxamic acids N-hydroxy-9-octadecenamide Oleic acid Rare earths