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A New Genetic Algorithm Based on Niche Technique and Local Search Method

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Journal of university of Science and Technology beijing 2001年第1期8卷 63-68页

作者： Jinwu Xu, Jiwen Liu mechanical engineering {2., university of Science and Technology beijing, beijing 100083, china Univ Sci & Technol beijing Sch Mech Engn Beijing 100083 Peoples R China

The genetic algorithm has been widely used in many fields as an easy robust global search and optimization method. In this paper, a new generic algorithm based on niche technique and local search method is presented under the consideration of inadequacies of the simple genetic algorithm. In order to prove the adaptability and validity of the improved genetic algorithm, optimization problems of multimodal functions with equal peaks, unequal peaks and complicated peak distribution are discussed. The simulation results show that compared to other niching methods, this improved genetic algorithm has obvious potential on many respects, such as convergence speed, solution accuracy, ability of global optimization, etc.

关键词： genetic algorithm (GA) niche technique local search method

Change Laws of Flake's Temperature during Making a Diamond Film by DC-PJ

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International Journal of Minerals,Metallurgy and Materials 1999年第2期13卷 97-102页

作者： Xuhong Chen Lihe Zhao Fanxiu Lu(mechanical engineering {2., university of Science and Technology beijing, beijing 100083, china) mechanical engineering {2. University of Science and Technology Beijing Beijing 100083 China

When making a diamond film by direct current plasma jet, a kind piece of flake is used as a base body Which the film can beattached to. The flake's temperature is unstable. Therefore, some experiments and constructed mathematical models, which were solvedby computer, were done. The results show that the flake's temperature is influenced by many factors and the mains are plasma jet powerand vacuum pressure. Through adjusting the two parameters, the flake's temperature can be accurately controlled, furthermore, diamondfilms' quality would be improved. Lowering sediment platform's temperature has a little effect to the flake's temperature at present technology conditions.

关键词： CVD (Chemical Vapor Deposition) plasma, impact heat transfer

Nonequilibrium Thermodynamic and Dissipative Structure Mechanism of Fluidized Beds

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International Journal of Minerals,Metallurgy and Materials 1999年第2期13卷 90-93页

作者： Maozhan Qi Li Wang Xuezi Ni (mechanical engineering {2., university of Science and Technology beijing, beijing 100083, china) mechanical engineering {2. University of Science and Technology Beijing Beijing 100083 China

Fluidized beds are nonlinear dynamic systems that exchange mass and energy with outside. They are governed not only byfluid dynamics, but by thermodynamics, especially the second law of thermodynamics as well. According to Prigogine's dissipative structure theory, the following have been concluded: (l) a fixed bed is on thermodynamic blanch, and bubbling, turbulent and fast beds areon the dissipatve structure branches. (2. Entropy in fluidized beds is divided into tWo parts: entropy production and entropy flux. The latter increases with gas velocity and decreases with pressure of the systems. That means the entropy of a system may reduce and the systemwith higher gas velocity behaves as dissipative structure characteristics. (3) For a giVen velocity, a fluidized bed operates stably on thewhole, but it is unstable to local gas-solid phases. The unstable phases are described by fluid dynamic equations, While the minimum ofsystem energy function assures whole stability of the system. (4) A transition criterion of a bubbling bed is derived from Prigogine's stability theory.

关键词： fluidized bed nonequilibrium thermodynamics dissipative structure energy extremum

PERFORMANCE EVALUATION OF SEVERAL FUSION APPROACHES FOR CCD/SAR IMAGES

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Chinese Geographical Science 2003年第1期13卷 91-96页

作者： WANG Yan-li, CHEN Zhe(school of automation Science and Electrical {2., beijing university of Aeronautics and astronautics, beijing 100083, P. R. china) school of automation Science and Electrical {2.， beijing university of Aeronautics and astronautics， beijing 100083， P. R. china

Several image fusion approaches for CCD/SAR images are studied and the performance evaluation of these fusion approaches is completed in this paper. Firstly, the preprocessing of CCD/SAR images before fusion is fulfilled. Then, the image fusion methods including linear superposition, nonlinear operator method and multiresolution methods, of which the multiresolution methods include Laplacian pyramid, ratio pyramid, contrast pyramid, gradient pyramid, morphological pyramid and discrete wavelet transform, are adopted to fuse two types of images. Lastly, the four performance measures, standard deviation, entropy, cross entropy and spatial frequency, are calculated to compare the fusion results by different fusion approaches in this paper. Experimental results show that contrast pyramid, morphology pyramid and discrete wavelet transformation in multiresolution approaches are more suitable for CCD/SAR image fusion than other ones proposed in this paper and the objective performance evaluation of CCD/SAR image fusion approaches are effective.

关键词： image fusion performance evaluation CCD image SAR image

Numerical Simulation of Shrinkage Cavity Formation in Spheroidal Graphite Iron Castings Based on Micro Modeling

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International Journal of Minerals,Metallurgy and Materials 1998年第1期12卷 9-12页

作者： Wenzhen Li Baicheng Liu Shantong Jin (Metallurgy engineering school, {2. of Science and Technology beijing, beijing 100083, china)(Department of mechanical engineering, Tsinghua {2., beijing 100084, china) Metallurgy engineering school University of Science and Technology Beijing Beijing 100083 China Department of mechanical engineering Tsinghua University Beijing 100084 China

A micro-modeling method (MM) for the quantitative prediction of the shrinkage cavity formation in SGiron castings is proposed. The mathematical models describing the volume changes during the solidification ofspheroidal graphite cast iron are established based on the models of solidification kinetics. The shrinkage cavityformation of T-shaped SG iron castings is calculated with MM method. The calculated results are compared with theexperimental results. It is shown that the predicted size, shape and distribution of shrinkage cavity by MM methodare in good agreement with the measured results.

关键词： solidification shrinkage numerical simulation micro modeling spheroidal graphite cast iron

Complex conforming Delaunay triangulation

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Science china(Information Sciences) 2010年第6期53卷 1130-1140页

作者： MENG XianHai 1, LI JiGang 1, YANG Qin 1, CAI Qiang 2.& CHEN QiMing 3 1 NLSDE, school of Computer Science and engineering, BeiHang {2., beijing 100083, china 2.school of Computer Sciences, beijing Technology and Business {2., beijing 100037, china 3 school of mechanical engineering and automation, BeiHang {2., beijing 100083, china 1. NLSDE School of Computer Science and Engineering BeiHang University Beijing 100083 China2. School of Computer Sciences Beijing Technology and Business University Beijing 100037 China3. School of Mechanical Engineering and Automation BeiHang University Beijing 100083 China

A novel algorithm of conforming Delaunay triangulation for curved geometry is presented in the paper.A progress has been made for the problem puzzled Delaunay refinement where curved constraints cannot be accepted as input *** algorithm is based on a new sufficient condition for the existence of constraints in *** requires computing only the intersection between constraints and Voronoi edges or faces instead of the circum-sphere of curved *** the termination of the algorithm when small input angles exist in constraints, a weighted method is applied to ensure that the algorithm can terminate under any *** two-dimensional and three-dimensional results are also *** is shown that the algorithm has the capability of dealing with both linear and nonlinear constraints in a consistent way, without the need of maintaining triangular meshes on face constraints.

关键词： mesh generation Delaunay triangulation conforming curved constraints tetrahedralization weight

Prediction and Control of both Wrinkle Limit and Fracture Limiton Cylindrical Cup Deep-drawing(Ⅱ)

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International Journal of Minerals,Metallurgy and Materials 1999年第3期13卷 201-204页

作者： Junxiang Lei Yonglin Kang(Department of mechanical engineering, Yantai {2., Yantai 2.4005, china)(Material Science and engineering school, {2. of Science and Technology beijing, beijing 100083, china) Department of mechanical engineering Yantai University Yantai 264005 China Material Science and engineering school University of Science and Technology Beijing Beijing 100083 China

The prediction and control criterion of both the wrinkle limit and fracture limit on the cylindrical cup deep-drawing are given, and the prediction and control diagram of both the wrinkle limit and fracture limit are also given. The results show that it is suitable for no-flange cylindrical cup deep-drawing, narrow-flange cylindrical cup deep-drawing, wide-flange cylindrical cup deep-drawing/expanding compound forming and rigid punch expanding forming.

关键词： cylindrical cup wrinkle limit fracture limit deep-drawing expanding forming compound forming

Theory and techniques of data mining in CGF behavior modeling

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Science china(Information Sciences) 2011年第4期54卷 717-731页

作者： YIN YunFei 1,2.GONG GuangHong 2.& HAN Liang 2.1 College of Computer Science,Chongqing university,Chongqing 400044,china 2.{2. of automation Science and Electrical engineering,beijing university of Aeronautics and astronautics,beijing 100083,china 1. College of Computer Science Chongqing University Chongqing 400044 China2. School of Automation Science and Electrical Engineering Beijing University of Aeronautics and Astronautics Beijing 100083 China

For the large quantity of data,rules and models generated in the course of computer generated forces (CGFs) behavior modeling,the common analytical methods are statistical methods based on the tactical rules,tactical doctrine and empirical ***,from the viewpoint of data mining,we can find many of these analytical methods are also each-and-every different data mining *** this paper,we survey the data mining theory and techniques that have appeared in the course of CGF behavior modeling from the viewpoint of data ***,we redefine and reclassify these theories and techniques according to the research requirements of data mining (the knowledge structure of data mining).We aim to help the CGF investigators to learn the key points and the research methods of the data intelligent processing in the CGF behavior modeling,and thus we can provide the references for the colleagues who are engaged in the research and practice of the CGF behavior modeling by this *** also introduce our ongoing work on the CGF behavior modeling based on data mining.

关键词： CGF CGF behavior modeling data mining theory and techniques

Cutting Performance and Mechanism of RE Carbide Tools

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Rare Metals 2001年第3期20卷 197-201页

作者： Jianbing Cheng, Yufang Wu, Qixun Yu 1) Department of mechanical engineering, {2. Technology and Business university, {2. 100037, china 2. College of mechanical engineering and automation, {2. Institute of Technology {2. 100081, china beijing Technol & Business Univ Dept Mech Engn Beijing 100037 Peoples R China beijing Inst Technol Coll Mech Engn & Automat Beijing 100081 Peoples R China

The research of rare earth elements (RE), added into cemented carbide tools, is one of the recent developments of new types of tool materials in china. Systematic experiments about RE carbides YG8R. (K30), YT14R (P2.) and, YW1R (M10) were made to study on the cutting performance in comparison with non-RE carbides YG8, YT14 and YW1. The cutting experiments were as follows: tool life, cutting force, tool-chip friction coefficient and interrupted machining. The action of RE on the carbide materials and the cutting mechanism of the RE carbide tools in the cutting process were verified with the aid of SEM and energy spectrum analysis. Experimental results show that the RE carbide tools have a good overall performance.

关键词： rare earth elements cemented carbide tool cutting performance cutting mechanism