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Effects of punch velocity on microstructure and tensile properties of thixoforged Mg2Sip/AM60B composite

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Transactions of Nonferrous Metals Society of China 2020年第1期30卷 110-122页

作者： su-qing zhang Ti-jun CHEN Ji-xue ZHOU State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou 730050China Shandong Provincial Key Laboratory of High Strength Lightweight Metallic Materials Qilu University of Technology(Shandong Academy of Science)Ji’nan 250014China

The effects of punch velocity on the microstructures and tensile properties of Mg2 Sip/AM60 B composite were *** comparison,the tensile properties of the permanent mold casting of this composite were also *** results indicate that the punch velocity obviously influences the microstructure through changing the secondary solidification behaviors and semisolid deformation *** variations of the microstructures and deformation mechanisms are responsible for the changes in tensile properties and fracture modes of the *** best comprehensive tensile properties of this composite are obtained under the punch velocity of 60 mm/*** resulting ultimate tensile strength and elongation of the composite are found to be 198 MPa and 10.2%,*** excellent tensile properties of the thixoforged composite are ascribed to the elimination of porosities and the work hardening.

关键词： thixoforging semisolid deformation fracture mechanism strengthening mechanism

Fabricating functionally graded Fe-Cr-Co permanent magnetic alloys via laser powder bed fusion

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Journal of Iron and Steel Research International 2024年第3期31卷 729-737页

作者： Ya-zhou He Ya-qing Hou Peng Shen Hao zhang Dong Zhou Hang su Central Iron and Steel Research Institute Co. Ltd.Beijing 100081China Material Digital R&D Center China Iron and Steel Research Institute Group Co.Ltd.Beijing 100081China

Laser powder bed fusion(LPBF)in-situ alloying technology offers the possibility to construct gradient materials with varied structures and *** graded Fe-Cr-Co permanent magnetic alloys were fabricated by LPBF and in-situ alloying mixed powders of Fe,Cr,and Co *** effects of different Fe,Cr and Co contents on the microstructure,magnetic properties and hardness of Fe-Cr-Co alloys prepared by LPBF were *** as-built Fe-Cr-Co alloys present a single body-centered-cubic phase and have a homogeneous distribution of *** mechanical properties and magnetic properties of the compositionally graded sample show a gradient *** the increase in Cr content,the Vickers hardness of the sample increases,and the saturation magnetization of the sample *** optimal magnetic properties in an isotropic state are given as coercivity HcB=21.65 kA/m,remanence Br=0.70 T and energy product(BH)_(max)=5.35 kJ/m^(3),which are comparable to or higher than the reported magnetic properties in an isotropic state prepared by traditional powder *** in-situ alloying technology has the potential to further explore Fe-Cr-Co magnetic materials,such as those consisting of multiple or more constituent elements,and to maximize the compositional flexibility of magnetic materials.

关键词： Fe-Cr-Co alloy Laser powder bed fusion In-situ alloying Functional material Magnetic property

Acid-rock reaction kinetics in a two-scale model based on reaction order correction

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Petroleum Science 2024年第3期21卷 2089-2101页

作者： Xue-Song Li Ning Qi Ze-Hui zhang Lian Liu Xia-qing Li Xu-Hang su School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580ShandongChina Key Lab of Unconventional Oil&Gas Development Ministry of EducationChina University of Petroleum(East China)Qingdao26650ShandongChina SINOPEC Northwest Oilfield Branch Company Urumqi830011XinjiangChina Petroleum Engineering Technology Research Institute SINOPEC Shengli Oilfield CompanyDongying257000ShandongChina

The reaction order plays a crucial role in evaluating the response rate of ***,the conventional two-scale model typically assumes that the reaction order is constant as one,which can lead to significant deviations from *** address this issue,this study proposes a novel multi-order dynamic model for acid-rock reaction by combining rotating disk experimental data with theoretical *** numerical simulations,this model allows for the investigation of the impact of acidification conditions on different orders of reaction,thereby providing valuable insights for on-site *** analysis reveals that higher response orders require higher optimal acid liquid flow rates,and lower optimal H+diffusion coefficients,and demonstrate no significant correlation with acid ***,it is recommended to increase the displacement and use high-viscosity acid for reservoirs with high calcite content,while reducing the displacement and using low-viscosity acid for reservoirs with high dolomite content.

关键词： Reaction order Two-scale model Wormhole propagation Carbonate rocks Numerical simulation

Composite Converter Combined APFC with Switched-capacitor Converter

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 281-291页

作者： qing Fu Yishan Chen Yixing su Yang Hang School of Physics Sun Yat-Sen UniversityGuangzhou 510275China

To reduce switch numbers and voltage stress in semiconductor devices,this paper proposes a novel single-phase converter combined Active Power Factor Correction(APFC)with switched-capacitor *** addition,dynamic voltage regulation and voltage gain are improved by integrating the boost converter and switching capacitor *** interstage bulk capacitor is no longer *** average current control with redistribution of voltage in cells is proposed to obtain voltage lift ability of the switching capacitor cells and maintain a high-power *** study and verify the proposed converter preliminarily,theoretical analysis and simulation are presented in the ***,a 50o W prototype with two different configurations is built for experimental *** proposed converter can reach 95.62%of maximum efficiency,0.99 of power factor,and 3.55%of THD with 600 V output voltage,simultaneously.

关键词： AC-DC converter composite conveter power factor correction switched capacitor

Learning topological defects formation with neural networks in a quantum phase transition

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Communications in Theoretical Physics 2024年第5期76卷 68-76页

作者： Han-qing Shi Hai-qing zhang Center for Gravitational Physics Department of Space ScienceBeihang UniversityBeijing 100191China Peng Huanwu Collaborative Center for Research and Education Beihang UniversityBeijing 100191China

Neural networks possess formidable representational power,rendering them invaluable in solving complex quantum many-body *** they excel at analyzing static solutions,nonequilibrium processes,including critical dynamics during a quantum phase transition,pose a greater challenge for neural *** address this,we utilize neural networks and machine learning algorithms to investigate time evolutions,universal statistics,and correlations of topological defects in a one-dimensional transverse-field quantum Ising ***,our analysis involves computing the energy of the system during a quantum phase transition following a linear quench of the transverse magnetic field *** excitation energies satisfy a power-law relation to the quench rate,indicating a proportional relationship between the excitation energy and the kink ***,we establish a universal power-law relationship between the first three cumulants of the kink numbers and the quench rate,indicating a binomial distribution of the ***,the normalized kink-kink correlations are also investigated and it is found that the numerical values are consistent with the analytic formula.

关键词： neural networks machine learning transverse-field quantum Ising model kibble-zurek mechanism

Microstructure and electrical conductivity of electroless copper plating layer on magnesium alloy micro-arc oxidation coating

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Transactions of Nonferrous Metals Society of China 2022年第12期32卷 3950-3962页

作者： Tao LI Zhong-jun LENG Xi-tao WANG Shi-fang WANG su-qing zhang Yuan-sheng YANG Ji-xue ZHOU Shandong Provincial Key Laboratory of High Strength Lightweight Metallic Materials Advanced Materials InstituteQilu University of Technology(Shandong Academy of Sciences)Jinan 250014China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China

In order to impart electrical conductivity to the magnesium alloy micro-arc oxidation(MAO)coating,the electroless copper plating was *** of plating temperature and complexing agent concentration on the properties of the electroless copper plating layers were studied by measuring their microstructure,corrosion resistance and electrical *** was found that the optimized plating temperature was 60°C,and the most suitable value of the complexing agent concentration was 30 g/*** this condition,a complete and dense plating layer could be *** formation mechanism of the plating layer on magnesium alloy MAO coating was analyzed.A three-stage model of the plating process was *** square resistance of the plated specimen was finally reduced to 0.03Ω/□after the third *** electroless copper plating,the MAO coated sample obtained excellent electrical conductivity without significantly reducing its corrosion resistance.

关键词： electroless copper plating electrical conductivity MAO coating magnesium alloy

Time-domain dynamic constitutive model suitable for mucky soil site seismic response

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 1-13页

作者： Dong qing Chen su Jin Liguo Zhou Zhenghua Li Xiaojun Architectural Engineering Institute Huaiyin Institute of TechnologyHuai’an 223600China Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100020China Institute of Geophysics China Earthquake AdministrationBeijing 100089China College of Transportation Science and Engineering Nanjing Tech UniversityNanjing 211816China

Soil nonlinear behavior displays noticeable effects on the site seismic *** study proposes a new functional expression of the skeleton curve to replace the hyperbolic skeleton *** integrating shear modulus and combining the dynamic skeleton curve and the damping degradation coefficient,the constitutive equation of the logarithmic dynamic skeleton can be obtained,which considers the damping effect in a soil dynamics *** on the finite difference method and the multi-transmitting boundary condition,a 1D site seismic response analysis program called Soilresp1D has been developed herein and used to analyze the time-domain seismic response in three types of *** the same time,this study also provides numerical simulation results based on the hyperbolic constitutive model and the equivalent linear *** results verify the rationality of the new soil dynamic constitutive *** can analyze the mucky soil site nonlinear seismic response,reflecting the deformation characteristics and damping effect of the silty *** hysteresis loop area is more extensive,and the residual strain is evident.

关键词： seismic response time-domain dynamic constitutive model logarithmic dynamic skeleton dampening effect mucky soil

UNIFORM ERROR BOUNDS OF A CONSERVATIVE COMPACT FINITE DIFFERENCE METHOD FOR THE QUANTUM ZAKHAROV SYSTEM IN THE suBSONIC LIMIT REGIME

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Journal of Computational Mathematics 2024年第1期42卷 289-312页

作者： Gengen zhang Chunmei su School of Mathematics and Statistics Yunnan UniversityKunming 650504China Yau Mathematical Sciences Center Tsinghua UniversityBeijing 100084China

In this paper,we consider a uniformly accurate compact finite difference method to solve the quantum Zakharov system(QZS)with a dimensionless parameter 0<ε≤1,which is inversely proportional to the acoustic *** the s... 详细信息

In this paper,we consider a uniformly accurate compact finite difference method to solve the quantum Zakharov system(QZS)with a dimensionless parameter 0subsonic limit regime,i.e.,when 0sults are reported to verify the error behavior.

关键词： Quantum Zakharov system subsonic limit Compact finite difference method Uniformly accurate Error estimate

Effects of processing parameters on microstructure and mechanical properties of powder-thixoforged 6061 aluminum alloy

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Transactions of Nonferrous Metals Society of China 2015年第3期25卷 699-712页

作者：陈玉狮陈体军张素卿李普博兰州理工大学有色金属先进加工与再利用国家重点实验室兰州730050

A new processing technology,powder thixoforming,for preparation of particle reinforced metal matrix composites was proposed and 6061 aluminum alloy was prepared by powder thixoforging.6061 ingots were first prepared by cold-pressing the atomized 6061 alloy powders,and then the ingots were partially remelted followed by *** effects of reheating time,mould temperature and reheating temperature on microstructure and mechanical properties of the thixoforged alloys were *** results indicate that all of the three parameters have large effects on the microstructure and mechanical *** to the microstructure changes,the fracture regime varies with the processing ***,cracks always initiate from shrinkage porosities and inclusions,and then propagate either along the secondarily solidified structures or primary *** ultimate tensile strength,elongation and hardness of the resulting alloy are up to 196 MPa,11.0%and HV 55.7 respectively.

关键词： 6061 aluminum alloy semisolid powder thixoforging mechanical properties tensile properties hardness microstructure