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Rare Metals 2010年第2期29卷 220-225页

作者： ZHANG Qian, ZHANG Boping, Li Haitao, and SHANG Pengpeng school of materials {2. and Engineering, university of {2. and Technology beijing, beijing 100083, china school of materials {2. and Engineering University of Science and Technology Beijing

Lead-free piezoelectric NaxK1-xNbO3（x = 0.3-0.8）（NKN） ceramics were fabricated by normal sintering at 1060°C for 2.*** and electrical properties of the ceramics were investigated with a special emphasis on the influence of Na *** grain size of the produced dense ceramic was decreased by increasing Na content.A discontinuous change in the space distance was found at the composition close to Na0.7K0.3NbO3 ceramic, which indicates the presence of a transitional composition between two different orthorhombic phases, which is similar to the behavior of morphotropic phase boundary（MPB） in NaxK1-xNbO3 *** MPB-like behavior contributes to the enhanced piezoelectric coefficient d33 of 12. pC/N, planar-mode electromechanical coupling coefficient kP of 2..6%, and dielectric constant εr of 703, respectively for the Na0.7K0.3NbO3 *** temperature TC and the transitional temperature TO-T from orthorhombic to tetragonal phase are observed at around 42.°C and 2.0°C, respectively.

关键词： lead-free piezoelectric ceramics NKN sintering morphotropic phase boundary(MPB)

Simulation of Temperature and Flow Field by Three Dimension Finite ElementMethod for Castex Process of AS Wire

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International Journal of Minerals,Metallurgy and materials 1999年第4期13卷 262-267页

作者： Zhiyuan Shi1 Wanjun Wang1 Zhigang Kan2.Jinglin Wen3 Xinhua Wang1(l Metallurgy school, university of {2. and Technology beijing, beijing 100083, china2.university of AViation and Spaceflight beijing, beijing 100083, china3 Northeastern university, Metallurgy school University of Science and Technology Beijing Beijing 100083 China university of Aviation and Spaceflight beijing Beijing 100083 China Northeastern university Shenyang China

Castex of AS wire is a new technology of near net shape. To study the variation of temperature and velocity of liquid (or semisolid) aluminum during dynamic solidification the numerical simulation was carried out with the theory of heat-transfer and hydrodynamics by means of 3-dimensional finite element method. From simulation results, it is found that the variation of temperature and velocityis mainly influenced by the casting temperature of aluminum, rotating speed of Castex wheel and flow of cooling water. Among theseinfluencing factors, the casting temperature distributes most to the length of liquid phase metal. Moreover, the faster the metal solidifies,the higher the metal there moves with the overall trend of descending from the bottom of the wheel to the shoe wall as well as from sidewalls to the center of wheel groove. In comparison with the practical value, the simulation is reliable.

关键词： Castex dynamic solidification AS wire temperature and flow field, finite element method

ESKD-A New Structure of Expert System Based on Knowledge Discovery

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International Journal of Minerals,Metallurgy and materials 2000年第1期14卷 63-71页

作者： Bingru Yang Fasheng liu Jiangtao Shen Information Engineering school, university of {2. and Technology beijing, beijing, 100083, china Information Engineering school University of Science and Technology Beijing Beijing 100083 China

A new structure of ESKD (expert system based on knowledge discovery system KD (D&K)) is first presented on the basis of KD (D&K)-a synthesized knowledge discovery system based on double-base (database and knowledge base) cooperating mechanism. With all new features, ESKD may form a new research direction and provide a great probability for solving the wealth of knowledge in the knowledge base. The general structural frame of ESKD and some sub-systems among ESKD have been described, and the dynamic knowledge base based on double-base cooperating mechanism has been emphased on. According to the result of demonstrative experi- ment, the structure of ESKD is effective and feasible.

关键词： knowledge discovery expert system dynamic knowledge base, double-base cooperating mechanism

Research progress in synthesis and catalysis of polyoxometalates

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Progress in Natural science:materials International 2005年第5期15卷 385-394页

作者： GONG Yun1, HU Changwen1* and LIANG Hong2.1. Department of Chemistry, school of science, the Institute for Chemical Physics, {2. Institute of Technology, {2. 100081, china 2. Chemical Industry Press, {2. 10002., china) Department of Chemistry School of Science the Institute for Chemical Physics Beijing Institute of Technology Beijing 100081 China Chemical Industry Press Beijing 100029 China

Recent progress in the synthetic chemistry and catalysis of polyoxometalates (POMs) is reviewed. The novel POMs and their derivatives emerging in nearly three years (2.02.2.04) are introduced, including POMs with novel structure, POMs-organic hybrid compounds and host-guest complexes. Our review is focused on the elaboration of POMs' supramolecular chemistry.

关键词： polyoxometalates hybrid host-guest structure supramolecule catalysis.

Mass transfer coefficients in metallurgical reactors

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Journal of university of science and Technology {2. 2003年第2期10卷 1-9页

作者： Ying QuMetallurgical Engineering school, university of {2. and Technology beijing, beijing 100083, china Univ Sci & Technol beijing Met Engn Sch Beijing 100083 Peoples R China

An overview on the application and achievements of physico-mathematicalmodeling of metallurgical processes in china is briefly declared. The important role of coefficientsin model formulation is shown from our experience. The mass transfer coefficients of the slag-metalreactions and the gas-metal reactions are discussed referring to the flow conditions near theinterface. The influence of the surface-active species on the mass transfer and the interfacialreaction is also discussed briefly.

关键词： mass transfer modeling pyrometallurgy reaction engineering interfacial flow stirring power

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,{2. 2.school of Automation science and Electrical Engineering,beijing university of Aeronautics and Astronautics,beijing 100083,{2. 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

A phenomenological constitutive equation for Rene 95 PM alloy and its application to isothermal forging process of turbine disk

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Journal of university of science and Technology {2. 2002年第4期9卷 282-286页

作者： Maicang Zhang, Jianxin Dong, Yanping Zeng, Xishan Xiematerials science and Engineering {2., university of science and Technology beijing, beijing 100083, china Mat. Sci. and Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The flow behavior of Rene 95 PM alloy was studied from 1050 to 1150 deg Cwith strain rate of 1 X 10^(-3), 1 X 10^(-2., 1 X 10^(-1) and 1 s^(-1). At a given temperature andstrain rate, flow curves exhibit a peak followed by flow softening up to a steady state. Moreover,at constant strain, flow stress increases with increasing strain rate and decreasing temperature. Anequation relating hyperbolic sine of flow stress to hot working parameters, such as strain, strainrate and temperature, was established by using multiple nonlinear regression method. A very goodagreement was found between predicted and experimental flow stress in all the strain rangeinvestigated. Application of the constitutive equation in predicting forming loads and flow behaviorand temperature distribution in both upper and lower dies in an isothermal forging process ofturbine disk of large dimension (about 630 mm) by means of a finite element code was systematicallyanalyzed.

关键词： constitutive equation finite element method isothermal forging Rene 95PM alloy

Dissolving of Nb and Ti carbonitride precipitates in microalloyed steels

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Journal of university of science and Technology {2. 2003年第5期10卷 78-80页

作者： Wenjin Nie, Shanwu Yang, Shaoqiang Yuan, and Xinlai Hematerials science and Engineering {2., university of science and Technology beijing, beijing 100083, china materials science and Engineering {2. University of Science and Technology Beijing Beijing 100083 China

The dissolving behaviour of Nb and Ti carbonitride precipitates inmicroalloyed steels during isothermal holding at 1300℃ was investigated by Transmission electronmicroscopy (TEM) and energy dispersion x-ray spectrum (EDX). It was found that all precipitates inNb-Ti microalloyed steel are (Nb, Ti)(C, N). With holding time increasing, the atomic ratio of Nb/Tiin precipitates decrease gradually. These precipitates still existe even after holding for 48 h at1300℃ while Nb(C, N) precipitates dissolve away in Nb microalloyed steel only after 4 h at the sametemperature. These results show that formation and thermostability of precipitates are considerablyinfluenced by interaction between Nb and Ti.

关键词： dissolving (Nb, Ti)(C, N) TEM EDX

Electro-Pulse on Improving Steel Ingot Solidification Structure

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International Journal of Minerals,Metallurgy and materials 1999年第2期13卷 94-96页

作者： Yong Tang Jianzhong Wang Daqing Cang(Metallurgy school, university of {2. and Technology beijing, beijing 100083, china) Metallurgy school University of Science and Technology Beijing Beijing 100083 China

Pulse Electric Discharging (PED) is a novel technique that can modify solidifying structure and reduce grain size. ItS effectsapplied to the high carbon liquid steel were presented here. The macrostructure and microstructure of the high carbon alloy steel werealso observed. Results show that (1 ) the length of columnar crystal at the edge of ingot without PED treatment is much longer than thatwith PED, and (2. the perlite lamellae of steel billets after deposed by PED are twisted and shortened. An explanation of those experimental results is given.

关键词： electro-pulse solidification structure steel ingot

Surface Nanocrystallization of Magnesium Alloy AZ91D by High-Energy Shot Peening

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Journal of Wuhan university of Technology(materials {2.) 2009年第4期24卷 515-519页

作者：张津 school of materials {2. & Engineering University of Science and Technology Beijing College of materials science & Engineering Chongqing University of Technology

High-energy shot peening （HESP）, a method to produce severe plastic deformation by high velocity flying balls, was applied on die cast magnesium alloy AZ91D. Effects of surface nanocrystallization by HESP and heat treatment at different temperatures were investigated. The mi- crostructure evolution was conducted using X-ray diffraction （XRD） and field emission scanning electronic microscopy （FESEM）. The hardness was measured by microhardness tester. The experimental results show that surface nanocrystrallization of AZ91D obtained by HESP would lead to the increase of microhardness. Low temperature heated at 100℃ for 1 h do not change the property obviously. However, both the microstructure and microhardness vary greatly after heat treatment at 400℃ for 1 h.

关键词： AZ91 D surface nanocrystallization HESP microhardnss corrosion resistance