检索结果-南通市图书馆

Rare Metals 2002年第2期21卷 142-151页

作者： ZHANG JianMetallurgical Engineering school.university of Science and technology beijing, beijing 100083, china Metallurgical Engineering School University of Science and Technology Beijing 北京 100083

Based on the phase diagrams, measured activities an the annexationprinciple, the calculating models of mass action concentrations forin-Pb-Ag and In-Bi-Sb ternary metallic melts have been *** results of calculation both agree with practice, and obey the lawof mass action, showing that the models formulated can reflect thestructural reality of the corresponding melts and the annexationprinciple is applicable to the them.

关键词： activity mass action concnetration th annexation principle In-PB-Ag

Calculating model of mass action concentrations for Ag-Au-Cu melts

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2002年第1期21卷 43-47页

作者： ZHANG Jian Metallurgy School, university of Science and technology beijing, beijing 100083, china Metallurgy School University of Science and Technology Beijing 北京 100083

Based on phase diagrams and measured activities, the calculatingmodel of mass action concentrations for het- erogeneous meltsAg-Au-Cu was formulated. Calculated results agree with the improvedresults of recent research work, Showing that the model formulatedcan reflect the structural characteristics of these melts. In thismodel, without the help Of any empirical parameters, only threeequilibrium constants are used, hence it is simple, lear, andfavorable to the sim- Plification of calculation.

关键词： activity mass action concentration eutectic Solid solution

CONVERSE REASONING FOR FULL DEPRESSION-FEATURE MODEL AND PROCESS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2003年第2期16卷 160-162页

作者： Shen XiaohongLiu XuanYu FangfangZhang LeiFeng TaoCollege of Mechanical Engineering and automation,beijing technology and Business university, beijing 100037, china College of Mechanical Engineering and automation Beijing Technology and Business University 北京 100037

A new approach, namely, 'defining protrusion-feature withdepression-parameter' is advanced, which focuses on the shortcomings of protrusion-featurealteration method; The full depression-feature model is built up, and a basic converse reasoningiterative algorithm for machining process is given. The detailed examination has been implemented onthe feature-based modeling system for light industry product (QJFMS) and the converse reasoning onfixture-based machining process is achieved.

关键词： protrusion-feature full depression-feature model reasoning iterativealgorithm

Cutting Performance and Mechanism of RE Carbide Tools

在线全文

学校读者我要写书评

暂无评论

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, beijing technology and Business university, beijing 100037, china 2) College of Mechanical Engineering and automation, beijing Institute of technology beijing 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 (P20) 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

EFFECT OF NITROGEN ON GRAPHITE MORPHOLOGY IN GRAY CAST IRON

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1993年第8期6卷 151-155页

作者： ZHAI Qijie HU Hanqi university of Science and technology beijing,beijing,china Faculty of Foundry,university of Science and technology beijing,beijing 100083,china beijing Univ of Science and Technology Beijing China

The distribution of N and morphology of graphite in gray cast iron containing N were studicd by adopting the man-made specimens of Fe-C-Si-Mn alloys with some N added. The N adsorbed along the interfaces between graphite and matrix together with solid- solutioned in graphite is believed to be the principal cause of morpholongical variation of graphite.

关键词： gray cast iron graphite morphology N

A MODIFIED ALGORITHM OF FINDING AN ELEMENT OF CLARKE GENERALIZED GRADIENT FOR A SMOOTH COMPOSITION OF MAX-TYPE FUNCTIONS A MODIFIED ALGORITHM OF FINDING AN ELEMENT OF CLARKE GENERALIZED GRADIENT FOR A SMOOTH COMPOSITION OF MAX-TYPE FUNCTIONS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2000年第5期18卷 513-520页

作者： Yan Gao (Department of Basic Science, china university of Mining and technology-beijing, beijing 100083, china) （北京）中国矿业大学北京 100083

This paper refers to Clarke generalized gradient for a smooth composition of max-type functions of the form: f(x) = g(x, maxj∈J1 f1j(x),''', maxj∈Jm fmj(x)), where x ∈Rn, Ji, i = 1,''',m are finite index sets, g and fij,j ∈ Ji, i = 1,... )m, are continuously differentiable on Rm+n and Rn, respectively. In a previous paper) we proposed an algorithm of finding an element of Clarke generalized gradient for f, at a point. In that paper, finding an element of Clarke generalized gradient for f, at a point, is implemented by determining the compatibilities of systems of linear inequalities many times. So its computational amount is very expensive. In this paper) we will modify the algorithm to reduce the times that the compatibilities of systems of linear inequalities have to be determined.

关键词： Nonsmooth optimization Clarke generalized gradient Max-type function.

Identifying rock blocks based on hierarchical rock-mass structure model

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2009年第10期52卷 1612-1623页

作者： XU NengXiong School of Engineering and technology, china university of Geosciences, beijing 100083, china School of Engineering and technology China University of Geosciences Beijing 100083 China

Rock-masses are divided into many closed blocks by deterministic and stochastic discontinuities and engineering interfaces in complex rock-mass engineering. Determining the sizes, shapes, and adjacent relations of blocks is important for stability analysis of fractured rock masses. Here we propose an algorithm for identifying spatial blocks based on a hierarchical 3D Rock-mass Structure Model (RSM). First, a model is built composed of deterministic discontinuities, engineering interfaces, and the earth's surface, and the deterministic blocks surrounded by these interfaces are traced. Then, in each deter-ministic block, a network model of stochastic discontinuities is built and the stochastic blocks are traced. Building a unitary wire frame that connects all interfaces seamlessly is the key for our algorithm to identify the above two kinds of blocks. Using this algorithm, geometric models can be built for block theory, discrete element method, and discontinuous deformation analysis.

关键词： rock-mass engineering discontinuity block identification 3D Rock-mass Structure Model network model of stochastic discontinuities

Sol-gel Preparation Copper-cadmium Halide DopedPhotochromic Glass Coating on Plate Glass

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2000年第1期14卷 34-37页

作者： ShiyongLuo Jiayun Zhang Jixiang Liu Metallurgy School, university of Science and technology beijing, beijing 100083, china Wuhan university of technology, Wuhan 430070, china Univ Sci & Technol beijing Met Sch Beijing 100083 Peoples R China Wuhan Univ Technol Wuhan 430070 Peoples R China

Copper-cadmium halide doped photochromic glass coating on plate glass has been prepared by a sol-gel process. The sample shows reversible photochromic effect. The results of X-ray diffraction (XRD) and infrared (IR) spectrum investigations indicate that the photochromic phase of tile coating is CuBr_xCl_(1-x), solid solution, and that the structure network of the coating is connected with the bonds of Si-O-Si, Si-O-B and Si-O-Al.

关键词： photochromic glass coating sol-gel photochromic phase, structure network

Reduced analysis and confirmatory research on co-adaptability theoretical solution to conflicting events in construction engineering projects

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2010年第2期53卷 480-485页

作者： HOU XueLiang1 , LU Mei2 & WANG Kai3 1 School of Business Administration, north china Electric Power university, beijing 102206, china 2 Department of Construction Management, Tsinghua university, beijing 100084, china 3 College of Management, beijing Jiaotong university, beijing 100084, china 1. School of Business Administration North China Electric Power University Beijing 102206 China2. Department of Construction Management Tsinghua University Beijing 100084 China3. College of Management Beijing Jiaotong University Beijing 100084 China

The co-adaptability theoretical solution to conflicting events in construction engineering projects has three problems. First, the transformation of constraint conditions of theoretical solution is very difficult in practical engineering applications; second, some coefficients are difficult to be determined; third, there are overfull circular arithmetic operations involved in it. To resolve these problems, a new method to reduce the theoretical solution complications is proposed. By analyzing the operating mechanism of theoretical solution model, redundancies in the theoretical solution can be eliminated, and the ISM mapping with the co-adaptability solution can be set up. Based on this approach, a procedure to solve practical conflicting events in construction projects is established by replacing characteristic variables with mathematic variables. The research results show that the procedure can replace the co-adaptability theoretical solution effectively and solve practical conflicting events in construction projects.

关键词： construction project conflict theoretical solution reduced analysis ISM confirmatory research

Theorems for Testing Local Activity of CNN and Application to Cardiac Purkinje Equations

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2000年第2期14卷 139-146页

作者： Lequan Min(Applied Science School, university of Science and technology beijing, beijing 100083, china) Applied Science School University of Science and Technology Beijing Beijing 100083 China

The theorems for testing the local in one-port cellular neural/inear network (CNN) cells with four local state variables are presented. Using the theorems computes the bifurcation diagrams of the cardiac Purkinje fiber (CPE) equations Which describethe long-lasting action and pace-maker potentials of the Purkinje fiber of the heart. The computer simulation shows that periodic trajectories or convergent trajectories of the CPF Equations can be foun if the cormsponing cell Parameters are located in a positive domainbut nearby edge of chaos. In particular a heart with approximate normal frequency of heartbeat but non-normal electrocardiogram maysuddenly stop by slightly perturbing the parameters of the corresponding CPF Equations when the Paramders are located nearby the edge of chaos in the bifurcation diagrams. This research seems to interpret reasonbly the phenomena that patients with cardiac diseases might suddenly die without warning.

关键词： cellular neural network local activity cardiac Purkinje fiber heartbeat