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Micro defects formation and dynamic response analysis of steel plate of quasi-cracking area subjected to explosive load

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Defence Technology（防务技术） 2024年第1期31卷 580-593页

作者： Zheng-qing zhou ze-chen Du Xiao Wang Hui-ling Jiang Qiang zhou Yu-long Zhang Yu-zhe Liu Pei-ze Zhang Research Institute of Macro-Safety Science University of Science and TechnologyBeijing100083China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing100083China School of Mechanical Engineering Nantong UniversityNantong226019China China North Industry Advanced Technology Generalization Institute Beijing100089China China Academy of Ordnance Science China

As the protective component,steel plate had attracted extensive attention because of frequently threats of explosive *** this paper,the evolution of microstructure and the mechanism of damage in the quasi-cracking area of steel plate subjected to explosive load were discussed and the relationships between micro defects and dynamic mechanical response were *** the explosion experiment,five observation points were selected equidistant from the quasi-cracking area of the section of the steel plate along the thickness direction,and the characteristics of micro defects at the observation points were analyzed by optical microscope(OM),scanning electron microscope(SEM) and electron backscattered diffraction(EBSD).The observation result shows that many slip bands(SBs) appeared,and the grain orientation changed obviously in the steel plate,the two were the main damage types of micro *** addition,cracks,peeling pits,grooves and other lager micro defects were appeared in the lower area of the *** stress parameters of the observation points were obtained through an effective numerical *** mechanism of damage generation and crack propagation in the quasicracking area were clarified by comparing the specific impulse of each observation point with the corresponding micro *** result shows that the generation and expansion of micro defects are related to the stress area(*** upper compression area,the neutral plane area,and the lower tension area).The micro defects gather and expand at the grain boundary,and will become macroscopic damage under the continuous action of tensile ***,the micro defects at the midpoint of the section of the steel plate in the direction away from the explosion center(*** horizontal direction) were also *** was found that the specific impulse at these positions were much smaller than that in the thickness direction,the micro defects were only SBs and a few micro cracks,and the those decrea

关键词： Explosive load Quasi-cracking area Micro defects Steel plate Dynamic response Numerical simulation

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On the optimal harvesting of size-structured population dynamics

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Applied Mathematics(A Journal of Chinese Universities) 2013年第2期28卷 173-186页

作者： LIU Yan CheNG Xiao-liang he ze-rong Department of mathematics Zhejiang University Institute of Operational Research and Cybernetics Hangzhou Dianzi University

This work is concerned with a kind of optimal control problem for a size-structured biological population ***-posedness of the state system and an adjoint system are proved by means of Banach＇s fixed point *** and uniqueness of optimal control are shown by functional analytical *** conditions describing the optimal strategy are established via tangent and normal cones *** results are of the first ones for this novel structure.

关键词： Body size population model optimal harvest maximum principle normal cone.

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Poly(vinylidene fluoride) Modified Commercial Paper as a Separator with Enhanced Thermal Stability and Electrolyte Affinity for Lithium-ion Battery

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Energy & Environmental Materials 2021年第4期4卷 664-670页

作者： ze Zhang Meiling zhou Ji Yu Jianxin Cai Zhenyu Yang College of Chemistry Key laboratory of Jiangxi Province for Environment and Energy CatalysisNanchang UniversityNanchang Jiangxi 330031China

Commercial paper is of great potential as a ready-made substrate to make battery separator due to superior electrolyte affinity of ***,the direct utilization of commercial paper as a separator is impracticable because of its micro-sized holes between coarse cellulose fibers,which might induce short ***,a novel reinforced composite separator is proposed by modifying commercial paper(CP)with highdielectric polymer poly(vinylidene fluoride)(PVDF)via a vacuum filtration *** paper substrate enables excellent electrolyte wettability and high ionic conductivity of the CP-PVDF composite separator due to the superior electrolyte affinity of cellulose ***,the strong hydrogen bonds between F atoms in PVDF and H atoms in the-OH groups of cellulose endow the separator with high thermal stability and mechanical ***,the CP-PVDF exhibits outstanding interfacial compatibility toward Li metal anode and guarantees the prominent cycle durability of symmetric Li/Li cells up to 600 *** a result,the LiFePO_(4)/Li cells assembled with CP-PVDF separator show dramatic rate performance with high discharge capacity of 113.7 m Ah g^(-1),and prolonged cycle life at 5 *** work indicates that the paper-based composite membranes possess great potential for high-safety and electrochemical performance batteries.

关键词： commercial paper electrolyte affinity enhanced thermal stability lithium-ion battery PVDF-modified separator

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Real-Time Iterative Compensation Framework for Precision Mechatronic Motion Control Systems

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IEEE/CAA Journal of Automatica Sinica 2022年第7期9卷 1218-1232页

作者： Chuxiong Hu Ran zhou ze Wang Yu Zhu Masayoshi Tomizuka State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084 Beijing Key Laboratory of Precision/Ultra-Precision Manufacture Equipments and Control Tsinghua UniversityBeijing 100084China Department of Mechanical Engineering University of CaliforniaBerkeleyCA 94720-1740 USA IEEE

With regard to precision/ultra-precision motion systems,it is important to achieve excellent tracking performance for various trajectory tracking tasks even under uncertain external *** this paper,to overcome the limitation of robustness to trajectory variations and external disturbances in offline feedforward compensation strategies such as iterative learning control(ILC),a novel real-time iterative compensation(RIC)control framework is proposed for precision motion systems without changing the inner closed-loop ***,the RIC method can be divided into two parts,i.e.,accurate model prediction and real-time iterative *** accurate prediction model considering lumped disturbances is firstly established to predict tracking errors at future sampling *** light of predicted errors,a feedforward compensation term is developed to modify the following reference trajectory by real-time iterative *** the prediction and compen-sation processes are finished in a real-time motion control sampling *** stability and convergence of the entire control system after real-time iterative compensation is analyzed for different *** simulation results consistently demonstrate that the proposed RIC framework possesses satisfactory dynamic regulation capability,which contributes to high tracking accuracy comparable to ILC or even better and strong robustness.

关键词： Precision motion control prediction model real-time iterative compensation trajectory tracking

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Probing the sign-changeable interaction between dark energy and dark matter with current observations

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Science China(Physics,Mechanics & Astronomy) 2018年第3期61卷 1-9页

作者： Juan-Juan Guo Jing-Fei Zhang Yun-he Li Dong-ze he Xin Zhang Department of Physics College of Sciences Northeastern University Center for High Energy Physics Peking University

We consider the models of vacuum energy interacting with cold dark matter in this study, in which the coupling can change sigh during the cosmological evolution. We parameterize the running coupling b by the form b（a） = boa ＋ be（1 - a）, where at the earlytime the coupling is given by a constant be and today the coupling is described by another constant bo. We explore six specific models with （i） Q = b（a）Hoρo, （ii） Q = b（a）Hoρde, （iii） Q = b（a）Hoρc, （iv） Q = b（a）Hρo, （v） Q = b（a）Hρde, and （vi） Q = b（a）Hρc. The current observational data sets we use to constrain the models include the JLA compilation of type Ia supernova data, the Planck 2015 distance priors data of cosmic microwave background observation, the baryon acoustic oscillations measurements and the Hubble constant direct measurement. We find that, for all the models, we have b0 〈 0 and be 〉 0 at around the lolevel, and b0 and be are in extremely strong anti-correlation. Our results show that the coupling changes sign during the evolution at about the lolevel, i.e., the energy transfer is from dark matter to dark energy when dark matter dominates the universe and the energy transfer is from dark energy to dark matter when dark energy dominates the universe.

关键词： interacting dark energy sign-changeable interaction running coupling observational constraints

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扭曲双层石墨烯的层间电导特性研究

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原子与分子物理学报 2025年第6期42卷 83-88页

作者：陶懿洲刘超方贺男南京邮电大学电子与光学工程学院南京210023

扭曲双层石墨烯(TBG)由于具有莫特绝缘和非常规超导等新奇的电学特性,在纳米技术领域存在巨大的应用潜力.本文基于光学衍射物理方法,构建了一个适用于TBG的理论模型,并利用该理论模型研究了TBG的层间电导特性.研究结果较好地解释了TBG... 详细信息

扭曲双层石墨烯(TBG)由于具有莫特绝缘和非常规超导等新奇的电学特性,在纳米技术领域存在巨大的应用潜力.本文基于光学衍射物理方法,构建了一个适用于TBG的理论模型,并利用该理论模型研究了TBG的层间电导特性.研究结果较好地解释了TBG层间电导随扭转角变化的实验结果,并阐明了其物理机制.此外,本文还计算了电极参数、隧穿层厚度以及界面势强度等物理因素对层间电导特性的影响.计算结果表明:随着电极化学势的增大,层间电导关于扭转角的变化曲线近似整体向上平移;层间电导随着上层隧穿层厚度的增加而衰减并趋于稳定,而随着下层隧穿层厚度振荡;TBG两层扭转石墨烯的界面势强度越强,则层间电导随扭转角下降得越快.

关键词：低维物理层间电导光学衍射方法扭曲双层石墨烯

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Characterization and in-situ formation mechanism of tungsten carbide reinforced Fe-based alloy coating by plasma cladding

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International Journal of Minerals,Metallurgy and Materials 2018年第4期25卷 439-443页

作者： Mi-qi Wang ze-hua zhou Lin-tao Wu Ying Ding ze-hua Wang College of mechanics and materials Hohai University

The precursor carbonization method was first applied to prepare W–C compound powder to perform the in-situ synthesis of the WC phase in a Fe-based alloy coating. The in-situ formation mechanism during the cladding process is discussed in detail. The results reveal that fine and obtuse WC particles were successfully generated and distributed in Fe-based alloy coating via Fe/W–C compound powders. The WC particles were either surrounded by or were semi-enclosed in blocky M7C3 carbides. Moreover, net-like structures were confirmed as mixtures of M23C6 and α-Fe; these structures were transformed from M7C3. The coarse herringbone M6C carbides did not only derive from the decomposition of M7C3 but also partly originated from the chemical reaction at the α-Fe/M23C6 interface. During the cladding process, the phase evolution of the precipitated carbides was WC → M7C3 → M23C6 ＋ M6C.

关键词： precursor carbonization tungsten carbide (WC) microstructure in-situ formation mechanism phase evolution

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Dilepton Production in an Expanding Hot Baryon-Rich Quark-Gluon Matter

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Chinese Physics Letters 1999年第4期16卷 259-261页

作者： he ze-jun ZHANG Jia-ju JIANG Wei-zhou QIU Xi-jun LIU Bo Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion AcceleratorLanzhou 730000 Institute of Nuclear Research Chinese Academy of SciencesShanghai 201800 Institute of High Energy Chinese Academy of SciencesBeijing 100039

From the full stopping scenario,a relativistic hydrodynamic model describing the evolution of the baryon-rich quark-gluon matter fire-cylinder has been *** on it,the rapidity Distribution of dileptons with intermediate invariant masses has been *** is found that the quark phase gives the dominant contribution to the dilepton spectrum due to the influence of the phase boundary on the evolution of the system,especially the dilepton yield is strongly suppressed with the increasing rapidity.

关键词： quark lepton invariant

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Spatial resolution and image processing for pinhole camera-based X-ray fluorescence imaging: a simulation study

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Nuclear Science and Techniques 2022年第5期33卷 135-153页

作者： ze he Ning Huang Peng Wang Zi-Han Chen Bo Peng Key Laboratory of Radiation Physics and Technology of the Ministry of Education Institute of Nuclear Science and TechnologySichuan UniversityChengdu 610064China

Spatial resolution and image-processing methods for full-field X-ray fluorescence(FF-XRF)imaging using X-ray pinhole cameras were studied using Geant4simulations with different geometries and algorithms for image *** main objectives were:(1)calculating the quantum efficiency curves of specific cameras,(2)studying the relationships between the spatial resolution and the pinhole diameter,magnification,and camera binning value,and(3)comparing image-processing methods for pinhole camera *** results were obtained using a point and plane source as the X-ray fluorescence emitter and an array of 100×100 silicon pixel detectors as the X-ray *** quantum efficiency of a back-illuminated deep depletion(BI-DD)structure was above 30%for the XRF energies in the 0.8–9 keV range,with the maximum of 93.7%at 4 *** best spatial resolution of the pinhole camera was 24.7μm and 31.3 lp/mm when measured using the profile function of the point source,with the diameter of 20μm,magnification of 3.16,and camera bin of 1.A blind deconvolution algorithm with Gaussian filtering performed better than the Wiener filter and Richardson iterative methods on FF-XRF images,with the signal-to-noise ratio of 7.81 dB and improved signalto-noise ratio of 7.24 dB at the diameter of 120μm,magnification of 1.0,and camera bin of 1.

关键词： Full-field X-ray fluorescence(FF-XRF) X-ray pinhole camera Spatial resolution Image processing

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Debye Screening Mass at Next-to-Leading Order and Charmonium Deconfinement in the Quark-Gluon Plasma

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Chinese Physics Letters 1998年第11期15卷 787-789页

作者： CheN Hong LIU BO he ze-jun Department of Physics Southwest China Normal UniversityChongqing 400715 Institute of High Energy Physics Chinese Academy of SciencesBeijing 100039 Shanghai Institute of Nuclear Research Chinese Academy of SciencesShanghai 201800

Debye screening mass at the next-to-leading order is studied by the resummation method based on perturbation theory at finite *** find that the critical temperature for the J/ψdissociation is 0.211 *** contributions from the next-to-leading order are important,and critical temperature and chemical potential are shifted lower values.

关键词： temperature Debye critical

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