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An Elasto-plastic Damage Constitutive Theory Based on Pair Functional Potentials and Slip Mechanism

Chinese Journal of Aeronautics 2010年第6期23卷 686-697页

作者： Liu fang Fu qiang Chen Cen Liang Naigang State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China

The deformation work rate can be expressed by the time rate of pair functional potentials which describe the energy of materi- als in terms of atomic bonds and atom embedding interactions. According to Cauchy-Born rule, the relations between the micro- scopic deformations of atomic bonds and electron gas and macroscopic deformation are established. Further, atomic bonds are grouped according to their directions, and atomic bonds in the same direction are simplified as a spring-bundle component. Atom embedding interactions in unit reference volume are simplified as a cubage component. Consequently, a material model com- posed of spring-bundle components and a cubage component is established. Since the essence of damage is the decrease and loss of atomic bonding forces, the damage effect can be reflected by the response functions of these two kinds of components. For- mulating the mechanical responses of two kinds of components, the corresponding elasto-damage constitutive equations are de- rived. Considering that slip is the main plastic deformation mechanism of polycrystalline metals, the slip systems of crystal are extended to polycrystalline, and the slip components are proposed to describe the plastic deformation. Based on the decomposition of deformation gradient and combining the plastic response with the elasto-damage one, the elasto-plastic damage constitutive equations are derived. As a result, a material model iormulated with spring-bundle components, a cubage component and slip components is established. Different from phenomenological constitutive theories, the mechanical property of materials depends on the property of components rather than that directly obtained on the representative volume element. The effect of finite deformation is taken into account in this model. Parameter calibration procedure and the basic characteristics of this model are discussed.

关键词： elasto-plastic damage constitutive relation finite deformation pair functional potentials Cauchy-Born rule slipmechanism component assembling model

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A fast scanning strategy based on trajectory shaping for atomic force microscopy

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Nano Research 2022年第7期15卷 6438-6446页

作者： Yinan Wu Yingao Chang Yongchun fang zhi Fan Institute of Robotics and Automatic Information System College of Artificial IntelligenceNankai UniversityTianjin 300350China Tianjin Key Laboratory of Intelligent Robotics Nankai UniversityTianjin 300350China

To improve the scanning speed of an atomic force microscopy(AFM),a smooth scanning pattern is elaborately devised via trajectory shaping in this paper,so as to achieve fast imaging without hardware ***,in the proposed scanning method,the piezoelectric actuator tracks a well-designed smooth periodic signal in x-direction,and simultaneously tracks a step signal in *** advantage of the proposed method is that it does not require additional data reprocessing to construct the morphology of the sample surface,while significantly increasing the scanning bandwidth restricted by the raster scanning ***,to directly utilize the height data collected by scanning to produce the sample morphology,the forward process in the common raster scanning mode is retained in the proposed method,the tracking signal in the forward process is thus set to a ramp function in *** addition,to ensure the continuity and smoothness of the entire tracking signal in x-direction,a segment of a sine curve is uniquely determined as the backward tracking signal by position and acceleration constraints,so as to ensure that the forward and backward curves are continuous and acceleration-continuous at the intersection ***,the frequency spectrum analysis of the designed smooth signal is carried out to exhibit the depressed amplitudes of high-frequency components,which demonstrates that the proposed method is able to reduce the resonance in AFM high-speed scanning,so as to improve the capacity of rapidly generating high-quality ***,convincing comparison experiments are implemented to verify the imaging performance of the designed scanning algorithm.

关键词： atomic force microscopy fast scanning smooth signal trajectory shaping

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Characterization of diffusion-bonded joint between Al and Mg using a Ni interlayer

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Rare Metals 2016年第7期35卷 537-542页

作者： Jian Zhang Guo-qiang Luo qiang Shen Lian-Meng Zhang zhi-Jun Huang Research and Development Center of Wuhan Iron and Steel(Group)Corporation Wuhan 430080China State Key Laboratory of Advanced for Materials Synthesis andProcessing Wuhan University of TechnologyWuhan 430070China

Aluminum and magnesium were joined through diffusion bonding using Ni interlayer. The micro- structure and mechanical performance of the A1/Ni/Mg joints at different temperatures was investigated by means of scanning electron microscope （SEM）, electro-probe microanalyzer （EPMA）, X-ray diffraction （XRD）, Vickers hardness testing, and shear testing. The results show that the addition of Ni interlayer eliminates the formation of Mg-A1 intermetallic compounds and improves the bonding strength of the A1/Mg joints. The AI/Ni/Mg joints are formed by the diffusion of A1, Ni and Mg, Ni. The microstructure at the joint interface from A1 side to Mg side is A1 substrate/A1-Ni reaction layer/Ni interlayer/Mg-Ni reaction layer/Mg substrate multilayer structure. The mi- crohardness of the Mg-Ni reaction layer has the largest value of HV 255.0 owing to the existence of Mg2Ni phase. With the increase of bonding temperature, the shear strength of the joints increases firstly and then decreases. The A1/Ni/Mg joint bonds at 713 K for 90 min, exhibiting the maximum shear strength of 20.5 MPa, which is greater than that of bonding joint bonded directly or with Ag interlayer. The fracture of the joints takes place at the Mg- Ni interface rather than the A1-Ni interface, and the frac- ture way of the joints is brittle fracture.

关键词： A1-Mg Ni foil Diffusion bonding Microstructure Shear strength

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Decoherence of a Double Quantum Dot Charge Qubit Approached with Redfield Equation

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Communications in Theoretical Physics 2009年第2期51卷 345-348页

作者： LI Zeng-Zhao LI zhi-qiang Department of Physics and Institute of Modern Physics Ningbo University Ningbo 315211 China

In this paper, we investigate the decoherence time of a double quantum dot （DQD） charge qubit in three kinds of baths through solving dynamics of the qubit. The dynamics of the qubit is investigated with Redfield master equation. It is shown that the decoherence time of the qubit in Ohmic bath has the same order of magnitude as the experiments reported. When the environment is modeled with the supra-Ohmic bath the decoherence time of the qubit is shorter than the experimental result. And when modeled with the sub-Ohmic bath the decoherence time of the qubit is longer than the experimental result.

关键词： quantum dot decoherence redfield equation

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Development of gated fiber detectors for laser-induced strong electromagnetic pulse environments

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Nuclear Science and Techniques 2021年第6期32卷 36-44页

作者： Po Hu zhi-Guo Ma Kai Zhao Guo-qiang Zhang De-Qing fang Bao-Ren Wei Chang-Bo Fu Yu-Gang Ma Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China School of Physical Science and Technology Shanghai Tech UniversityShanghai 201210China School of Nuclear Sciences and Technology University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201210China

With the development of laser technologies,nuclear reactions can happen in high-temperature plasma environments induced by lasers and have attracted a lot of attention from different physical ***,studies on nuclear reactions in plasma are still limited by detecting *** is mainly due to the fact that extremely high electromagnetic pulses(EMPs)can also be induced when high-intensity lasers hit targets to induce plasma,and then cause dysfunction of many types of traditional ***,new particle detecting technologies are highly *** this paper,we report a recently developed gated fiber detector which can be used in harsh EMP *** this prototype detector,scintillating photons are coupled by fiber and then transferred to a gated photomultiplier tube which is located far away from the EMP source and shielded *** those measures,the EMPs can be avoided which may result that the device has the capability to identify a single event of nuclear reaction products generated in laser-induced plasma from noise EMP *** new type of detector can be widely used as a time-of-flight(TOF)detector in high-intensity laser nuclear physics experiments for detecting neutrons,photons,and other charged particles.

关键词： Gated fiber detector Radiation detection High-intensity laser Strong electromagnetic pulses

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Short-Time Effects of Environment to Josephson Charge Qubit: A Master Equation Approach

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Communications in Theoretical Physics 2008年第7期50卷 77-80页

作者： LI zhi-qiang LIANG Xian-Ting Department of Physics and Institute of Modern Physics Ningbo University Ningbo 315211 China

In this paper we investigate an environmental effects to Josephson charge qubit (JCQ) when the environmentis taken as the Ohmic *** first,we derive the master equation from a JCQ-bath *** we investigate thecoefficients of the equations that describe the shift in frequency,diffusive,decoherence,and so *** is shown that ourresult on decoherence agrees with experimental one very well as the time is short enough.

关键词： decoherence master equation Josephson charge qubit

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Potential for Constraining Propagation Parameters of Galactic Cosmic Rays with the High Energy Cosmic-radiation Detection Facility on Board China's Space Station

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Research in Astronomy and Astrophysics 2023年第8期23卷 290-296页

作者： zhi-Hui Xu qiang Yuan zhi-Cheng Tang Xiao-Jun Bi Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China

Precise measurements of the spectra of secondary and primary cosmic rays are crucial for understanding the origin and propagation of those energetic *** High Energy Cosmic-radiation Detection(HERD)facility on board China's Space Station,which is expected to operate in 2027,will push the direct and precise measurements of cosmic-ray fluxes up to PeV *** this work,we investigate the potential of HERD for studying the propagation of cosmic rays using measurements of boron,carbon,and oxygen *** find that,compared with the current results,the new HERD measurements can improve the accuracy of the propagation parameters by 8%–40%.The constraints on the injection spectra at high energies will also be improved.

关键词： (ISM:)cosmic rays-instrumentation detectors-The Galaxy

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Symmetry Reductions and Explicit Solutions for a Generalized Zakharov-Kuznetsov Equation

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Communications in Theoretical Physics 2006年第1期45卷 29-32页

作者： YAN zhi-Lian LIU Xi-qiang School of Mathematical Sciences Liaocheng University Liaocheng 252059 China

Two types of symmetry of a generalized Zakharov-Kuznetsov equation are obtained via a direct symmetry method. By selecting suitable parameters occurring in the symmetries, we also find some symmetry reductions and new... 详细信息

关键词： generalized Zakharov-Kuznetsov equation symmetry explicit solution

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Squeezing for Entangled States of Two Entangled Particles with Different Masses

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Communications in Theoretical Physics 2008年第8期50卷 486-488页

作者： LI zhi-qiang FAN Hong-Yi Department of Physics Ningbo University Ningbo 315211 China Department of Material Science and Engineering University of Science and Technology of China HeM 230026 China

Using the technique of integration within an ordered product of operators we present a convenient approach for introducing the squeezing operator for the entangled states of two entangled particles with different *** ... 详细信息

关键词： entangled particles with different masses one-sided squeezing operators

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Sb nanoparticles encapsulated in N-doped carbon nanotubes as freestanding anodes for high-performance lithium and potassium ion batteries

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Rare Metals 2023年第2期42卷 449-458页

作者： Xiao-Ping Lin fang-fang Xue zhi-Gang Zhang Qiu-Hong Li Pen-Tung Sah Institute of Micro-Nano Science and Technology Xiamen UniversityXiamen361005China

Sb-based materials with high specific capacity have targeted as an alternative anode material for alkali metal ion ***,Sb nanoparticles embedded in hollow porous N-doped carbon nanotubes(Sb@N-C nanotubes)are used as freestanding anode for Li-ion batteries(LIBs)and K-ion batteries(PIBs).The Sb@N-C nanotubes demonstrate exceptional reversible capacity of643 mAh·g^(-1)at 0.1 A·g^(-1)with long cycle stability,as well as outstanding rate performance(219.6 mAh·g^(-1)at10 A·g^(-1))in *** the anode material of PIBs,they reveal impressive capacity of 325.4 mAh·g^(-1)at 0.1 A·g^(-1).The superior electrochemical properties mainly originate from the novel *** be specific,the obtained 3D connected network allows for quick ion and electron migration,and prevents the aggregation of Sb *** hollow porous nanotubes can not only accommodate the volume expansion of Sb nanoparticles during cycling,but also facilitate the infiltration of the electrolyte and reduce the ion diffusion *** work provides a new insight for designing advanced Sb-based anodes for alkali metal ion batteries.

关键词： Alkali metal ion batteries Freestanding electrode Hollow porous nanotube Sb@N-C nanotubes

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