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Optimization of thermomechanical processes in Cu-Cr-Zr lead frame alloy using neural networks and genetic algorithms

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science china(Technological sciences) 2005年第5期48卷 510-520页

作者： SU Juanhua1,2. LIU Ping2. DONG Qiming2.& LI Hejun1 1. College of Materials science and engineering, Northwestern Polytechnical {2., Xi’an 710072. china 2. College of Materials science and engineering, Henan {2. of science and Technology, Luoyang 471003, china 1. College of Materials science and engineering Northwestern Polytechnical University 710072 Xi’an China 2. College of Materials science and engineering Henan University of Science and Technology 471003 Luoyang China

The thermomechanical treatment process is effective in enhancing the properties of the lead frame copper alloy. In this study, an optimal pattern of the thermomechanical processes for Cu-Cr-Zr was investegated using an intelligent control technique consisting of neural networks and genetic algorithms. The input parameters of the artificial neural network (ANN) are the reduction ratio of cold rolling, aging temperature and aging time. The outputs of the ANN model are the two most important properties of hardness and conductivity. Based on the successfully trained ANN model, genetic algorithms (GA) are used to optimize the input parameters of the model and select perfect combinations of thermomechanical processing parameters and properties. The good generalization performance and optimized results of the integrated model are achieved.

关键词： Cu-Cr-Zr alloy, thermomechanical processing optimization, artificial neural network, genetic algorithms.

Shape Character of Fusion-solidification Zone of EBW Joints for Titanium Alloy

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稀有金属材料与工程 2011年第S4期40卷 74-78页

作者： Fu Pengfei1,2.Mao Zhiyong2.Wang Yajun3,Gong Shuili2.Liu Xin2.1school of Materials science and {2.,Huazhong university of science and Technology,Wuhan 430074,china 2.1} and Technology on Power Beam Processes Laboratory,beijing Aeronautical Manufacturing Technology Research Institute,beijing 10002.,china3school of Mechanical {2. and Automation,beijing university of Aeronautics and Astronautics,beijing 100191,china beijing Aeronaut Mfg Technol Res Inst Sci & Technol Power Beam Proc Lab Beijing 100024 Peoples R China Huazhong Univ Sci & Technol Sch Mat Sci & Engn Wuhan 430074 Peoples R China beijing Univ Aeronaut & Astronaut Sch Mech Engn & Automat Beijing 100191 Peoples R China

Shape character of fusion-solidification zone of electron beam welding (EBW) joints was studied for TC4 *** typical shapes of the fusion-solidification zone were gained by appropriate welding *** shapes and dimensions of the fusion-solidification zone of TC4 titanium joints were apparently influenced by processing parameters,focusing state and power density *** on the analyses of processing parameters,focusing state and power density distribution,the integrated parameters of n1 and n2.were put forward,which represented the distribution and intensity of electron beam *** a series of the formulations are developed to predict the shape of fusion-solidification zone by the processing parameters.

关键词： electron beam welding (EBW) titanium alloy fusion-solidification zone mathematical model

The evolution and morphological stability of a spherical crystal

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science china(Technological sciences) 2008年第3期51卷 225-243页

作者： CHEN MingWen1,2. WANG ZiDong2.& XU JianJun3,4 1 school of Applied sciences, {2. of science and Technology beijing, beijing 100083, china 2.school of Materials science and engineering, {2. of science and Technology beijing, beijing 100083, china 3 school of Mathematical sciences, Nankai {2., Tianjin 300071, china 4 Department of Mathematics and Statistics, McGill {2., Montreal H3A 2.6, Canada 1. school of Applied sciences University of Science and Technology Beijing Beijing 100083 China 2. school of Materials science and {2. University of Science and Technology Beijing Beijing 100083 China 3. school of Mathematical sciences Nankai University Tianjin 300071 China 4. Department of Mathematics and Statistics McGill University Montreal H3A 2K6 Canada

The growth model of a spherical crystal in the undercooled melt including the surface energy, interfacial kinetics and convective flow is established. The effect of the convective flow induced by a small far field flow on the evolution and morphological stability of the interface of the spherical crystal is studied. The interface shape of the spherical crystal, which is affected by the far field flow, and the dispersion relation of the growth rate of amplitude of the perturbed interface are derived. It is shown that the convection induced by the far field flow makes the interface of the growing spherical crystal further grow in the upstream direction of the far field flow and inhibit growth in the downstream direction; the interface of the decaying spherical crystal further decays in the upstream direction and inhibits decay in the downstream direction. The theoretical result suggests that both the growth of the sphere in the upstream direction and the decay of the sphere in the downstream direction make the spherical crystal tend to evolve into an oval; the morphological stability of the interface depends on a certain radius R c such that the spherical crystal is unstable when its radius is greater than R c and stable when its radius is less than R c . The surface energy and interfacial kinetics have strong stabilizing effects on the growth of the spherical crystal. In the meantime interfacial kinetics is a table factor of the interface when the interface of the sphere is growing; it is an unstable factor of the interface when the interface is decaying.

关键词： solid-liquid interface spherical crystal convective flow crystal growth morphological stability

Matrix calculation of high-dimensional cross product and its application in automatic recognition of the endmembers of hyperspectral imagary

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science china(Information sciences) 2011年第1期54卷 197-203页

作者： GENG XiuRui1,ZHAO YongChao1,LIU SuHong2.& WANG FuXiang3 1Key Laboratory of Technology in Geo-spatial Information Processing and Application System, Institute of Electronics,Chinese Academy of sciences,beijing 100080,{2. 2.tate Key Laboratory of Remote Sensing science,Jointly Sponsored by beijing Normal university and the Institute of Remote Sensing Applications of Chinese Academy of sciences, school of Geography,beijing Normal university,beijing 100875,{2. 3school of Electronics and Information engineering,beihang university,beijing 100191,{2. 1. Key Laboratory of Technology in Geo-spatial Information Processing and Application System Institute of Electronics Chinese Academy of Sciences Beijing 100080 China2. State Key Laboratory of Remote Sensing Science Jointly Sponsored by Beijing Normal University and the Institute of Remote Sensing Applications of Chinese Academy of Sciences School of Geography Beijing Normal University Beijing 100875 China3. School of Electronics and Information Engineering Beihang University Beijing 100191 China

This paper gives the definition of the high-dimensional cross product and its calculation by extending the 3-D cross product definition into the high-dimensional vector *** on the properties of the cross product,the volume variance index(VVI)is proposed to be used in extracting automatically the endmembers of the hypherspectral imagery which eliminates the shortcoming of the traditional method of using simplex only where the extraction results were easily impacted by the abnormal pixels.A case study of endmembers extraction experiment using the VVI method with the AVIRIS data for Cuprite has shown a very good result.

关键词： endmember simplex hyperspectral imagery cross product

Quasi-equality constrained risk-sensitive filtering for nonlinear discrete-time systems

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控制理论与应用（英文版） 2012年第2期10卷 229-235页

作者： Linfeng SHEN, Yan LIN school of Automation science and Electrical {2., beijing university of Aeronautics and Astronautics, beijing 100191, china school of Automation science and Electrical {2. Beijing University of Aeronautics and Astronautics Beijing China

More and more data fusion models contain state constraints with valuable information in the filtering process. In this study, an optimal filter of risk sensitive with quasi-equality constraints is formulated using the reference probability method. Through recursion processes of probability density acquired from the probability measure change, the derived algorithm is optimal in the sense of the risk sensitive parameter. The system and constraint models are Consistent in statistics. Simulation results show that it is more robust and efficient than projection filters for the worst-case of noises and model uncertainty.

关键词： Optimal estimation Risk-sensitive filtering Constraints

Nonlinear Theory on Dynamic Controlling Interface Patterns DuringSolidification of a Dilute Binary Alloy

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International Journal of Minerals,Metallurgy and Materials 1999年第4期13卷 253-258页

作者： Zidong Wang Hanqi Hu(Material science and engineering {2., university of science and Technology beijing, beijing 100083, china) Material science and engineering {2. University of Science and Technology Beijing Beijing 100083 China

In non-equilibrium nonlinear region, the nonlinear equations of time dependence of perturbation amplitude at the solid/liquidinterface during solidification of a dilute binary alloy are established on the base of assuming that there is local equilibrium at the solid/liquid interface and considering that curvature, temperature and composition at the solid/liquid interface which are related to the perturbation amplitude are nonlinear. As a result, patterns at the solid/liquid interface during solidification process, which is from nonsteadystate to steady state can be controlled by these nonlinear equations.

关键词： nonlinearity solidification, dilute binary alloy, dynamic control

Effect of trace Zn,P and Mg additions on microstructure and mechanical properties of Nb-Si-Ti alloys

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Progress in Natural science:Materials International 2011年第2期21卷 139-145页

作者： Mei-ling WU,Shu-suo LI,Li-wu JIANG,Sheng-kai GONG,Ya-fang HAN school of Materials science and {2.,beihang university,beijing 100191,china school of Materials science and {2. Beihang University Beijing 100191 China

The effects of Zn,P and Mg additions on the microstructure and mechanical properties of Nb-2.Ti-3Si alloys were studied. The phases of Nbss and Nb3Si presented in Nb-2.Ti-3Si(AC1),Nb-2.Ti-3Si-0.2.n(AC2. and Nb-2.Ti-3Si-0.2.g alloys(AC3). The Nb-2.Ti-3Si-0.2.(AC4) alloy consisted of Nbss,Nb3Si network and eutectic cell of Nbss/α-*** the addition of Zn,the Nb3Si network was broken and the volume fraction of Nbss increased from 92.to 96%.The values of fracture toughness of the alloy AC2.at ambient temperature increased from 2.,58 MPa·m1/2.o 2..41 MPa·m1/*** values of compressive strength for the Zn-added alloy at ambient temperature and 1 2.0℃increased from 1 52..10 MPa to 1 652.44 MPa,and from 2.8.52.MPa to 2.4.18 MPa,*** with the alloy AC1,the addition of P promoted the formation ofα-Nb5Si phase but the values of fracture toughness and compressive strength of alloy at room temperature and 1 2.0℃*** contrast,the addition of Mg improved the compressive strength at ambient temperature and 12.0℃from 1 52..10 MPa to 1 618.08 MPa and from 2.8.52.MPa to 348.2. MPa,*** relationship between the microstructure and the mechanical properties was discussed.

关键词： Nb-Si-Ti alloy Zn addition P Mg microstructure mechanical property

Producing Calcium-Bearing Mullite Thermal-Insulating Refractories by Kyanite

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International Journal of Minerals,Metallurgy and Materials 1999年第1期13卷 50-53页

作者： Wen Ni (Resources engineering school, {2. of science and Technology beijing, beijing 100083, china) Resources engineering school University of Science and Technology Beijing Beijing 100083 China

To improve the physical properties, a series of experiments have been camed out to produce calcium-bearing mullite thermal-insulating refractories by using kyanite as major raw materials. The experiments were carried out by a foaming technique and using white cement as a combing agent. The results show that the calcium-bearing mullite refractory has much better physical properhes than traditional clay refractory and high-alumina refractory.

关键词： mullite thermal-insulating refractory kyanite

Performance analysis of network coding for multicast relay system over Nakagami-m fading channels

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science china(Information sciences) 2011年第11期54卷 2338-2348页

作者： ZHAO Rui 1,YANG LvXi 2.& HUANG YongMing 2.1 school of Information science and {2.,Huaqiao university,Xiamen 36102.,china 2.school of Information science and {2.,Southeast university,Nanjing 2.0096,china 1. school of Information science and {2. Huaqiao University Xiamen 361021 China2. School of Information Science and Engineering Southeast University Nanjing 210096 China

The outage probability performance of network coding for multicast relay system is analyzed in Nakagami-m fading *** transmission strategies,i.e.,complex field network coding (CFNC) and amplify-and-forward network coding (AFNC),are applied in the system,and the approximate expressions of outage probability are derived at high SNR and the conclusion is reached that the system diversity gains of two transmission strategies are both 2.,as is verified by numerical *** results also show that CFNC can outperform both AFNC and direct transmission without relay in the performances of system outage probability,sum rate and symbol error ratio.

关键词： multicast relay system network coding outage probability diversity gain