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Grain Growth Kinetics of BaTiO3 Nanocrystals During Calcining Process

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Chinese Journal of Chemical Physics 2008年第3期21卷 295-300页

作者： Xiao-lan Song Xi He Hai-ping Yang Yi-xin Qu guan-zhou Qiu School of Resources Processing and BioenEineerinE Central South University Changsha 410083China College of Chemical Engineering Beijing University of Chemical Technology Beiging 100029China

BaTiO3 nanocrystals were synthesized by sol-gel method using barium acetate （Ba（CH3COO2） and tetrabutyl titanate （Ti（OC4H9）4） as raw materials. Xerogel precursors and products were characterized by means of thermogravimetric/differential scanning calorimetry （TG/DSC）, X-ray diffraction （XRD） and transmission electron microscope （TEM）. The influence of the calcination temperature and duration on the lattice constant, the lattice distortion, and the grain size of BaTiO3 nanocrystals was discussed based on the XRD results. The grain growth kinetics of BaTiO3 nanocrystals during the calcination process were simulated with a conventional grain growth model which only takes into account diffusion, and an isothermal model proposed by Qu and Song, which takes into account both diffusion and surface reactions. Using these models, the pre-exponential factor and the activation energy of the rate constant were estimated. The simulation results indicate that the isothermal model is superior to the conventional one in describing the grain growth process, implying that both diffusion and surface reactions play important roles in the grain growth process.

关键词： BaTiO3 nanocrystal Sol-gel method Grain growth kinetics

Microstructure and performance of AZ80D magnesium alloy by purification of chloride flux containing Er

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Rare Metals 2014年第5期33卷 541-546页

作者： Zhong-Jun Wang guan-Qiao Su Wei-ping Jia Qing-Xiang Yang School of Material and Metallurgy University of Science and Technology Liaoning Key Laboratory of Materials Forming and Microstructure and Properties Control Education Department in Liaoning Province State Key Laboratory of Metastable Materials Science and Technology College of Materials Science and EngineeringYanshan University

The purification effects of Er addition in chloride flux during smelting on microstructure, tensile properties, and corrosion resistance of as-cast AZ80 D magnesium alloy were carried out. The results show that Er addition in the flux can eliminate the MgO inclusions and improve the tensile properties and corrosion resistance of the alloy. Using chloride flux mixed with 8.0 wt% Er, σb and δ of the as-cast AZ80 D magnesium alloy can be improved from 150 MPa and 2.1 % to the maximum value of 230 MPa and 4.8 %, respectively. Meanwhile, the corrosion rate decreases from 1.10 to 0.12 mg·（cm^2·d）^-1 in 5 wt% NaCl solution. However, with increasing Er content in chloride flux further, φ-（Al7ErMn5） and τ-（Al66.7Mg23.3Er10） phase are formed, and the morphology of γ-（Mg17Al12） phase is modified. The coarse φ-（Al7ErMn5）phase along dendrite boundaries decreases cohesion force between dendrites, which results in the worse of tensile properties.

关键词： Er Chloride flux AZ80D Microstructure Magnesium alloy

Transverse Bending Characteristics in U-channel Forming of Tailor Rolled Blank

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Journal of Iron and Steel Research International 2016年第12期23卷 1249-1254页

作者： Hua-wei ZHANG Ying-ping guan Jia-lu WU Xiang-hua LIU School of Control Engineering Northeastern University at Qinhuangdao College of Mechanical Engineering Yanshan University Research Institute of Science and Technology Northeastern University

Research on the formability of tailor rolled blank （TRB） is of good practical significance and application value because of the enormous potential of TRB in the aspect of automobile lightweight. However, the forming of TRB is problematic because of the varying properties; especially, springback is a main challenge. The transverse bending （bending axis is perpendicular to the rolling direction） of TRB U channel was studied through simulation and experiment. The forming characteristics of TRB U channel during transverse bending were analyzed. The mechanisms of forming defects, including bending springback and thickness transition zone （TTZ） movement, were revealed. On this basis, effects of blank geometric parameters on springbaek and TTZ movement were discussed. The results indicate that springback and TTZ movement happen during transverse bending of TRB U-channel. Nonuni form stress distribution is the most fundamental reason for the occurrence of springback of TRB during transverse bending. Annealing can eliminate nonuniform stress distribution, and thus diminish springbaek of TRB, especially springback on the thinner side. Therefore, springback of the whole TRB becomes more uniform. However, annealing can increase the TTZ movement. Blank thickness and TTZ position are the main factors affecting the formability of TRB U-channel during transverse bending.

关键词： tailor rolled blank transverse bending springback U-channel annealing thickness transition zone

Comparison and research on the GRAVEL and PRIP algorithms of neutron energy spectrum unfolding

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Radiation Detection Technology and Methods 2017年第2期1卷 15-20页

作者： guan-ying Wang Ran Han jin-liang Liu Xiao-ping Ouyang jin-cheng He Jun-yao Yan North China Electric Power University Beijing 102206China Beijing Institute of Spacecraft Environment Engineering Beijing 100029China Northwest Institute of Nuclear Technology Xi’an 710024ShaanxiChina

Objective Neutron energy spectrum unfolding is a key technique for neutron *** is essentially an inversion *** GRAVEL algorithm has been widely used in this field,and the PRIP algorithm transforms neutron energy spectrum unfolding into a typical nonnegative linear complementarity problem and solves it by interior point algorithm for potential *** These two algorithms are applied to unfold several different neutron energy test spectra and actual D-T fusion neutron energy *** and Conclusion By comparison,it can be concluded that the PRIP algorithm is highly computationally efficient and fast converging,and the GRAVEL algorithm solution results match up more with the expected results.

关键词： Neutron energy spectrum Unfolding Geant4 PRIP algorithm GRAVEL algorithm

The Harmonic Decomposition Reconstruction for the Exponential Radon Transform

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Wuhan University Journal of Natural Sciences 2002年第1期7卷 1-5页

作者： Wang jin-ping Du jin-yuan School of Mathematics and Statistics Wuhan University Wuhan 430072 Hubei China

The exponential Radon transform, a generalization of the Radon transform, is defined and studied as a mapping of function spaces. It is represented in terms of Fourier transform of its domain and range, and this leads... 详细信息

关键词： exponential radon transform Fourier transform harmonic decomposition inversion

Kinetic analysis of austenite transformation for B1500HS high-strength steel during continuous heating

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International Journal of Minerals,Metallurgy and Materials 2020年第11期27卷 1508-1516页

作者： Mu-yu Li Dan Yao Liu Yang Hao-ran Wang Ying-ping guan Key Laboratory of Advanced Forging&Stamping Technology and Science(Ministry of Education of China) Yanshan UniversityQinhuangdao 066004China School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004China

The dilatometric curves of B1500HS high-strength steel at different heating rates were measured by a Gleeble-3800 thermal simulator and analyzed to investigate the effect of heating rate on *** show that the value of starting temperature and ending temperature of austenite transformation increase with the rise of heating rates,whereas the temperature interval of austenite formation *** kinetic equation of austenite transformation was solved using the Johnson–Mehl–Avrami model,and the related parameters of the equation were analyzed by the Kissinger *** those calculations,the activation energy of austenite transformation is 1.01×10^6 J/mol,and the values of kinetic parameters n and ln k0 are 0.63 and 103.03,*** relationship between the volume fraction of austenite and the heating time at different heating rates could be predicted using the kinetic *** predicted and experimental results were compared to verify the accuracy of the kinetic *** microstructure etched by different corrosive solutions was analyzed,and the reliability of kinetic equation was further verified from the microscopic perspective.

关键词： B1500HS high-strength steel dilatometric curve austenite transformation kinetic equation Johnson-Mehl-Avuami model

Analytic Formulae for Estimating Motor Proportion of Load Model Under Small Disturbance

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1599-1607页

作者： ping Ju Shiqiu Xia Yuqing jin Lu Cao School of Electrical and Power Engineering Hohai UniversityNanjing 211100China the East China Branch of the State Grid Corporation of China Shanghai 200120China

In the composite load model(CLM),which is commonly used in China,an equivalent motor and equivalent static load are used to represent all electrical equipment and networks connected to a load *** research has determined typical values of electrical and mechanical parameters for load models of different load types,which improves the basis for load ***,the motor proportion parameter is not the same for different load buses or at different times;therefore,obtaining the actual motor proportion is key to establishing an accurate load *** the existing load modeling method,motor proportion is commonly identified along with other parameters under rare large disturbances;therefore,the value of the motor proportion is fixed by the time when a large disturbance *** this paper,formulae are derived to estimate motor proportion under small disturbances,and these formulae allow direct calculation of motor proportion without using any optimization *** proposed estimation formulae do not rely on any parameters of load model or power system but instead rely only on measurement of the voltage and active power at steady-state points before and after a small *** of universality of small disturbances in power systems,estimating time-varying motor proportion under small disturbances will be helpful for solving the time-varying problem of load ***,the proposed motor proportion estimation formulae are validated by simulations,physical experiments,and field experiments.

关键词： Composite load model load modeling motor proportion parameter estimation

High-current pulsed electron beam modification on microstructure and performance of Cu/CuW diffusion bonding joints

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Rare Metals 2024年第6期43卷 2819-2831页

作者： Na-Na Tian Cong-Lin Zhang Peng Lyu jin-Tong guan Jie Cai Qing-Feng guan Shun Guo School of Materials Science and Engineering Jiangsu UniversityZhenjiang 212013China School of Material Science and Engineering Yancheng Institute of TechnologyYancheng 221051China Engineering Institute of Advanced Manufacturing and Modern Equipment Technology Jiangsu UniversityZhenjiang 212013China

This study investigates the influence of high-current pulsed electron beam(HCPEB)modification on the microstructure and shear strength of Cu/CuW *** solid-state diffusion bonding of modified-Cu(MCu)and modified-CuW(M-CuW)was achieved by HCPEB modification pretreatment at a temperature of 800-900℃and a pressure of 5 MPa for 10-50 *** demonstrate that HCPEB modification facilitates the dissolution of W and Cu,resulting in the formation of a Cu_(0.4)W_(0.6)solid solution and thus enhancing the uniform distribution of ***,HCPEB-induced defects play a beneficial role in promoting the diffusion process by providing fast diffusion paths for *** optimal joints with the maximum shear strength of 213.7 MPa were obtained through bonding M-Cu and M-CuW at 900℃and 5 MPa for 30 min,which attributes to the combined effects of fine-grained strengthening and solid solution ***,the application of HCPEB modification showcases its effectiveness in promoting element diffusion and enhancing the mechanical performance of the joints.

关键词： HCPEB Element diffusion Shear strength Crystal defects Surface modification

Neutrophil diversity and plasticity:Implications for organ transplantation

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Cellular & Molecular Immunology 2023年第9期20卷 993-1001页

作者： Junwen Qu jingsi jin Ming Zhang Lai guan Ng Shanghai Immune Therapy Institute Renji HospitalShanghai Jiao Tong University School of MedicineShanghai 200127China Department of Urology Renji HospitalShanghai Jiao Tong University School of MedicineShanghai 200127China

Neutrophils,as the first defenders against external microbes and stimuli,are highly active and finely regulated innate immune *** evidence has challenged the conventional dogma that neutrophils are a homogeneous population with a short lifespan that promotes tissue *** findings on neutrophil diversity and plasticity in homeostatic and disease states have centered on neutrophils in the *** contrast,a comprehensive understanding of tissue-specialized neutrophils in health and disease is still *** article will first discuss how multiomics advances have contributed to our understanding of neutrophil heterogeneity and diversification in resting and pathological *** discussion will be followed by a focus on the heterogeneity and role of neutrophils in solid organ transplantation and how neutrophils may contribute to transplant-related *** goal of this article is to provide an overview of the research on the involvement of neutrophils in transplantation,with the aim that this may draw attention to an underappreciated area of neutrophil research.

关键词： Neutrophil Heterogeneity Transplantation