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β-Sialon Produced by Carbon Thermal Nitriding Reaction of Bauxite

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International Journal of Minerals,Metallurgy and Materials 2000年第3期14卷 209-213页

作者： Jun Wang, Nan Li, Caicheng Shi, Chengchang Jia ( Material science and engineering school, university of science and technology Beijing, Beijing 100083, china Material science and engineering school, Wuhan university of science and technology, Wuhan 430 Material science and engineering school University of Science and Technology Beijing Beijing 100083 China Material science and engineering school Wuhan University of Science and Technology Wuhan 430081 China

β-Sialon was produced by carbon thermal nitriding reaction in N_2 gas atmosphere when the mixtures of bauxite and anthracite were put into vertical furnace. According to the mass loss of raw materials and the result of X-ray diffration (XRD) of products, the influences of the process parameters on the compositions and relative contents of products, such as the fixed carbon content, the flow of N2, the soaking time and the temperature, were researched.

关键词： β-Sialon bauxite anthracite carbon thermal nitriding processing parameter vertical furnace

Jamming de-chirping radar using interrupted-sampling repeater

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science china(Information sciences) 2011年第10期54卷 2138-2146页

作者： FENG DeJun ,TAO HuaMin,YANG Yong & LIU Zhong school of electronic science and engineering,National university of Defense technology,Changsha 410073,china school of electronic science and engineering National University of Defense Technology Changsha China

Interrupted-sampling repeater jamming (ISRJ) is a novel jamming mode for pulse compression radar in *** this paper,a jamming approach of applying ISRJ to de-chirping radar is *** principles of ISRJ are expounded,and the ways to achieve a train false target for de-chirping radar are *** characteristics of false target,including time-domain characteristic,frequency-domain characteristic and amplitude characteristic,are *** on this,the power requirement for jammer is put forward and the key elements that determine the space distribution location between true and false targets are discussed in *** last,simulation results are presented and *** work is beneficial to the jamming design and use of ISRJ.

关键词： interrupted-sampling repeater de-chirping wideband radar linear frequency modulated signal

New Delay-Dependent Stability of Uncertain Discrete-Time Switched Systems with Time-Varying Delays

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Journal of Mathematical Research and Exposition 2011年第2期31卷 224-232页

作者： Liang Lin XIONG 1,2,Shou Ming ZHONG 2,3,Mao YE 4 1.school of Mathematics and Computer science,Yunnan Nationalities university,Yunnan 650031,P.R.china 2.school of Applied Mathematics,university of electronic science and technology of china,Sichuan 610054,P.R.china 3.Key Laboratory for NeuroInformation of Ministry of Education,university of electronic science and technology of china,Sichuan 610054,P.R.china 4.school of Computer science and engineering,university of electronic science and technology of china,Sichuan 610054,P.R.china school of Mathematics and Computer science Yunnan Nationalities University Yunnan 650031 school of Applied Mathematics University of Electronic Science and Technology of China Key Laboratory for Neurolnformation of Ministry of Education Sichuan 610054 school of Computer science and engineering University of Electronic Science and Technology of China Sichuan 610054

This paper deals with the issues of robust stability for uncertain discrete-time switched systems with mode-dependent time *** on a novel difference inequality and a switched Lyapunov function,new delay-dependent stability criteria are formulated in terms of linear matrix inequalities （LMIs） which are not contained in known literature.A numerical example is given to demonstrate that the proposed criteria improves some existing results significantly with much less computational effort.

关键词： discrete-time switched system difference inequality switched Lyapunov function delay-dependent stability linear matrix inequality (LMI)

Electrochemical Characteristic of Decarburization Reaction

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International Journal of Minerals,Metallurgy and Materials 1999年第1期13卷 27-30页

作者： Xionggang Lu Fushen Li Lifen Li Kouchih Chou (Applied science school, university of science and technology Beijing, Beijing 100083, china)(Material science and engineering school, Shanghai university, Shanghai 200072, china) Applied science school University of Science and Technology Beijing Beijing 100083 China Material science and engineering school Shanghai University Shanghai 200072 China

The electrochemical mechanism of the reaction between Fe-C melts and CaO-SiO2-Al2O3-FeOx slag systems has been carried out. The experimental results suggest that the final content of carbon in melt increases as the partial oxygen pressure of gas decreases no matter whether there is electronic conductor or not. However, the final content of carbon in the system with electronic conductor is much lower than that without electronic conductor. It can be deduced that the transfer ability of oxygen in slag is dominated by electrons. When an electronic conductor exists, an easy pathway for the electrons is provided and the oxygen transfer rate is accelerated.

关键词： melt-slag reaction decarburization electrochemistry electronic conductor

Applicability of mass action law to sulphur distribution between slag melts and liquid iron

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Journal of university of science and technology Beijing 2002年第2期9卷 90-98页

作者： Jian Zhang Metallurgy school, university of science and technology Beijing, Beijing 100083, china Metall. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

According to the mass action law and the coexistence theory of slagstructure, the calculating models of mass action concentration for CaO-MgO-FeO-Fe_2O_3-SiO_2,CaO-MgO-MnO-FeO-Fe_2O_3-P_2O_5-SiO_2 and CaO-MgO-MnO-FeO-Fe_2O_3-Al_2O_3-P_2O_5-SiO_2 slag melts areformulated and sulphur distribution between the slag melts and liquid iron is treated. It is foundthat CaO, MnO and FeO promote desulphurization, while MgO is detrimental to desulphurization. Inaddition, the sulphur distribution coefficients between the slag melts and liquid iron andpresented.

关键词： mass action law coexistence theory of slag structure activity massaction concentration

Carbon Solubility and Mass Action Concentrations of Fe-Cr-C Melts

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International Journal of Minerals,Metallurgy and Materials 2000年第2期14卷 86-91页

作者： Jtan Zhang(Metallurgy school, university of science and technology Beijing, Beijing 100083, china) Metallurgy school University of Science and Technology Beijing Beijing 100083 China

An empirical equation of carbon solubility in Fe-Cr-C melts is regressed based on the experimental data from references. Acalculating model of mass action concentrations for these melts is formulated on the basis of the coexistence theory of metaIlic melts in-volving compound formation, the phase diagram of Cr-C system as well as thermodynamic data of Fe-Cr-C melts. According to the mod-el, the standard Gibbs free energies of formation of CrC and Cr3C2 are obtained. Satisfactory agreement between the calculated and me-asured values shows that the model can reflect the structural characteristics of Fe-Cr-C melts.

关键词： activity, coexistence theory mass action concentration saturated state

Approximately optimal tracking control for discrete time-delay systems with disturbances

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Progress in Natural science:Materials International 2008年第2期18卷 225-231页

作者： Gongyou Tang a,,Huiying Sun b,Haiping Pang c a College of Information science and engineering,Ocean university of china,Qingdao 266100,china b College of Information and Electrical engineering,Shandong university of science and technology,Qingdao 266510,china c College of Automation and electronic engineering,Qingdao university of science and technology,Qingdao 266042,china College of Information science and engineering Ocean University of China Qingdao 266100 China College of Information and Electrical engineering Shandong University of Science and Technology Qingdao 266510 China College of Automation and electronic engineering Qingdao University of Science and Technology Qingdao 266042 China

Optimal tracking control (OTC) for discrete time-delay systems affected by persistent disturbances with quadratic performance index is considered. By introducing a sensitivity parameter,the original OTC problem is transformed into a series of two-point boundary value (TPBV) problems without time-advance or time-delay terms. The obtained OTC law consists of analytic feedforward and feedback terms and a compensation term which is the sum of an infinite series of adjoint vectors. The analytic feedforward and feedback terms can be found by solving a Riccati matrix equation and two Stein matrix equations. The compensation term can be obtained by using an iteration formula of the adjoint vectors. Observers are constructed to make the approximate OTC law physically realizable. A simulation example shows that the approximate approach is effective in tracking the reference input and robust with respect to exogenous persistent disturbances.

关键词： Discrete systems Time-delay systems Disturbances Optimal control Tracking control

Application of annexation principle to the study of thermodynamic properties of Ag-Bi-In metallic melts

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Journal of university of science and technology Beijing 2003年第1期10卷 18-20页

作者： Jian ZhangMetallurgy school, university of science and technology Beijing, Beijing 100083, china Metall. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

Based on the measured activities, the phase diagrams and the annexation principle, the calculating models of mass action concentrations for Ag-Bi and Ag-Bi-In melts have been formulated. The calculated results agree with practice and obey the mass action law, showing that the models formulated can reflect the structural characteristics of both melts. Meanwhile, it confirms that annexation principle is applicable to the Ag-Bi-In metallic melts. The melts involving eulectic which give rise to phase separation, and in which activities exhibit positive deviation from Raoult's law is the basic cause of melts transforming from homogeneous to heterogeneous ones.

关键词： the mass action law annexation principle two phase melts activity, mass action concentration

THEORETICAL DESIGN AND MOTION PLANNING OF NONHOLONOMIC MANIPULATOR

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Chinese Journal of Mechanical engineering 2004年第2期17卷 222-225页

作者： Tan Yuegang Deng Yuhui WU Zhengping school of Mechanical and electronic engineering,Wuhan university of technology,Wuhan 430070, china school of Mechanical and electronic engineering Wuhan University of Technology Wuhan 430070

A new nonholonomic transmission mechanism is proposed based on thenonholonomic theory and nonlinear control principle, and combined with conditions of thenonholonomic motion planning and control, that is researched to compose method of the motiontransfer chain from this transmission mechanism, on which a new nonholonomic manipulator isdesigned. This nonholonomic manipulator is a controllable multi-joint manipulator that actuated onlyby two-servo electromotor. Its motion expresses the characteristic of nonholonomy constraint andnonlinear, and that also satisfies the chained form convertibility. And then, using the nonlinearcontrol principle of chained system, motion characteristic of the nonholonomic manipulator isapplied. From simulation verification and analysis, the usefulness of the theoretical design andcontrol strategies is shown, and that is important in design and research of handiness robot andmulti-finger robot hand.

关键词： Nonholonomic system Nonholonomic motion planning Nonlinear controlMulti-joint Manipulator