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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, university of science and technology beijing, beijing 100083, china)(Department of Mechanical Engineering, Tsinghua university, 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

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 science 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

Application of Potentiostats Using PC in the Phase Analysis of Galvano-Chemis-try

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International Journal of Minerals,metallurgy and Materials 2000年第2期14卷 151-153页

作者： Bo Wen Xinyu liu Xinhua Wang Wanjun Wang Xang Ma(Information Engineering school, university of science and technology beijing, beijing 100083, china)(metallurgy school, university of science and technology beijing, beijing 100083, china)(beijing Resea Univ Sci & Technol beijing Informat Engn Sch Beijing 100083 Peoples R China Univ Sci & Technol beijing Met Sch Beijing 100083 Peoples R China beijing Res Inst Iron & Steel Beijing 100081 Peoples R China

A set of device is designed based on PC to realize the functions of traditional potentiostats in the phase ana1ysis of galvanochemistry. In the device, A/D and D/A conversion is used to measure the electrode potential and convert the voltage for outPut; specific program runs in the PC to regulate and control the system. The effect of the proportion factor Kp on the control variation is researched through certain experiment. Two experiments, the control of electrolysis in constant poteniial and the determination of polarization curves, are designed to test and evaluate the effectiveness of the device. The experimemel results show that the variation between the actualanode potential and the target potential could be controlled to below 1 mV if Kp is set to an appropriate value.

关键词： potentiostat PC phase analysis of galvano-chemistry

A New Process for Preparing Fine-ceramic-containing Composite Coatings──Flame Spray Synthesis

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International Journal of Minerals,metallurgy and Materials 2000年第3期14卷 214-217页

作者： Changsong liu, Jihua Huang, Sheng Yin (Material science and Engineering school, university of science and technology beijing, beijing 100083, china) Material science and Engineering school University of Science and Technology Beijing Beijing 100083 China

Flame spray synthesis (FSS), a combination of the flame spray technology and Self-propagation High-temperature Synthesis (SHS) was developed for preparing fine-ceramic-containing composite coatings. It can simplify the preparations of powder to synthesize and deposit the desired materials in one step. The preliminary results obtained from TiC-Fe cermet coatings by FSS process are reported. The peculiar microstructure of the composite coatings, which contains very fine (<1m) and round TiC and alternate TiC-rich (Hv=11€*13GPa) and TiC-poor layers (Hv=3.0 -6.0GPa), is expected to play an important role in their tribological properties.

关键词： Self-propagation High-temperature Synthesis (SHS) flame spray flame spray synthesis (FSS) TiC-Fe cermet coating

Electrochemical Studies of Lithium Intercalation into Graphite Film Electrode for Li^+-ion Batteries

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International Journal of Minerals,metallurgy and Materials 2000年第1期14卷 48-50页

作者： Chuangang Lin Weihua Qiu Qingguo liu Material science and Engineering school, university of science and technology beijing, beijing 100083, china Material science and Engineering school University of Science and Technology Beijing Beijing 100083 China

To study the electrochemical kinetic properties of the Li/Graphite system, cycle voltammerty (CV), ac-impedance and chro- noamperometry (CA) techniques have been used. The results showed that the diffusion of lithium ions in Li_xC_6 is the rate-determining step. The chemical diffusion coefficients of lithium (D_Li) have been estimated for different x values. As for the same material, the value of D_Li was calculated in order to compare the differences among the three techniques.

关键词： electrochemical studies graphite Li^+-ion batteries

XPS Study of CeO_2/Al_2O_3 film

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International Journal of Minerals,metallurgy and Materials 1999年第3期13卷 199-200,204页

作者： Mei Zhang Zhenxiang liu Kan Xie Xueyan Du Wenchao Li(metallurgy school, university of science and technology beijing, beijing 100083, china)(Institute of physics Chinese Academy of science, beijing 100080, china) Univ of science and technology Beijing Beijing China

The redox capacity of CeO2/Al2O3 thin film which was prepared by sol-gel method has been investigated by X-ray Photoelectron Spectrascopy (XPS). The results showed that the thin film was easier to be reduced and re-oxidized than pure CeO2 powder. The key role played by oxygen vacancies which were created from the interaction between CeO2 and Al,O, was also discussed.

关键词： CeO_2/Al_2O_3 thin film redox interaction XPS

Photoluminescence Properties of Porous Silicon Based on FZ(H) Si Wafer

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Rare Metals 2001年第1期20卷 38-42,57页

作者： Yuejiao He, Huaixiang Li, Chenghua Guo, Guirong liu, Yansheng Chen, Shuzhen Duan (Institute of Semiconductors, Shandong Normal university, Jinan 250014, china metallurgy school, university of science and technology beijing, beijing 100083, china) Shandong Normal Univ Inst Semicond Jinan 250014 Peoples R China Univ Sci & Technol beijing Met Sch Beijing 100083 Peoples R China

The photoluminescence (PL) properties of porous silicon (PS) have been studied based on n-type single-crystal (111) silicon wafers (80-90 Omega .cm in the resistivity). The porous silicon layers (PSL) were created by anodizing the wafers with a denuded zone of 20-40 mum formed by neutron transmutation doping (NTD) and thermal treatment at 940 degreesC for 4 h and then 700 degreesC for 2 h, two-step heating of the floating-zone silicon (FZ Si) grown in a hydrogen (H,) ambience. By surface modification with stannic chloride or amine immersion and rapid thermal oxidation (RTO), the PL peak position from the PS can be qualitatively controlled factitiously. The as-prepared PS shows an orange-yellow luminescence, while the modified samples emit red, green and blue luminescence. Mechanisms for the different colors of the PL are discussed. Fourier transform infrared (FTIR) is carried out to analyze the differences in the structural configuration of the PS samples.

关键词： porous silicon photoluminescence surface modification rapid thermal oxidation

A New High Quality EAF Charge

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Journal of university of science and technology beijing 2001年第1期8卷 20-21页

作者： Jianliang Zhang, Yuquan liu, Zongwang Zhang, Jinlin Jia ,Yongmei Zhang metallurgy school, university of science and technology beijing, beijing 100083, china Tianjin Iron Corporation, Handan 056000, china Univ Sci & Technol beijing Met Sch Beijing 100083 Peoples R China Tianjin Iron Corp Handan 056000 Peoples R China

In order to solve the problem of the shortage of scrap, especially high quality scrap, granular pig iron, a new substitute for scrap or DRI (direct reduction iron) has been developed. The technical process of decarbonized granular pig iron has been evaluated. The result shows that this new process is superior to direct reduction process in product quality, construction investment, operation flexibility, production efficiency etc. Decarbonized granular pig iron (DGPI) not only can be used as conventional scrap but also can be charged into EAF as high purity burden equivalent to heavy scrap.

关键词： decarbonized granular pig iron scrap DRI

Thermoelectric properties of porous (Bi_(0.15)Sb_(0.85))_2Te_3 thermoelectric materials

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Journal of university of science and technology beijing 2003年第5期10卷 39-43页

作者： Guiying Xu, Tingjie Chen, Jianqiang liu, and Zhangjian ZhouLaboratory of Special Ceramics and Powder metallurgy, Materials science and Engineering school, university of science and technology beijing, beijing 100083, china Lab. of Special Ceramics Mat. Sci. and Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

In order to obtain thermoelectric materials with high figure of merit, theconcept of Hollow (Vacuum) Quantum Structure or Effect and related thermoelectric materials designwere proposed. To demonstrate the theory, the materials of (Bi_(0.15)Sb_(0.85))_2Te_3 with porousstructure have been fabricated. Their thermoelectric properties and the microstructure wereinvestigated and compared with their density structure. It was found that the porous structure couldimprove their properties greatly.

关键词： thermoelectric materials Bi_xSb_(1-x) Bi_2Te_3 hollow quantum effect