检索结果-南通市图书馆

Systems Science and Systems Engineering 1994年第1期4卷 83-88页

作者： xia guoping zhao hengfeng(department of management, beijing university of aeronautics & astronautics,beijing 100085)

The pap.r presents three aspects of implementation of dynamic imagine and Hyp.rtext in exp.rt ***,we design the man-machine interface by using Dynamic Imagine to improve flekibilities of receiving ***, we focus on how to make use of the dynamic to develop the attificial ability of exp.rt systems. Finally,we use hyp.rtext to build the objective data structure as the base of the production of subjective data.

关键词： exp.rt systems systems imagine hyp.rtext subjective data

Non-existence of positive solution to a quasilinear elliptic system and blow-up estimates for a reaction-diffusion system

在线全文

学校读者我要写书评

暂无评论

Communications in Nonlinear Science and Numerical Simulation 2001年第4期6卷 222-226页

作者： Zuodong YANG and Qishao LU department of Applied Mathematics, beijing university of aeronautics and astronautics, beijing 100083, china department of Applied Mathematics Beijing University of Aeronautics and Astronautics Beijing 100083 China

The non-existence result for radially nonincreasing positive solutions of the system is implied. By using this non-existence result. blow-up estimates for a class of quasilinear reaction-diffusion systems (non-Newtoni... 详细信息

关键词： blow-up. quasilinear reaction-diffusion system. positive radial solutions existence and non-existence

Optimal Ap.roach to SAr Image Despeckling

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2002年第1期13卷 48-52页

作者： Zheng Zonggui & Mao Shiyi department of Electronic Engineering, beijing university of aeronautics and astronautics, beijing 100083,p.r.china department of Electronic Engineering Beijing University of Aeronautics and Astronautics Beijing 100083 P. R. China

Speckle filtering of synthetic ap.rture radar (SAr) images while preserving the spatial signal variability (texture and fine structures) still remains a challenge. Many algorithms have been proposed for the SAr imagery despeckling. However, simulated annealing (SA) methods is one of excellent choices currently. A critical problem in the study on SA is to provide ap.ropriate cooling schedules that ensure fast convergence to near-optimal solutions. This pap.r gives a new necessary and sufficient condition for the cooling schedule so that the algorithm state converges in all probability to the set of global minimum cost states. Moreover, it constructs an ap.ropriate objective function for SAr image despeckling. An exp.rimental result of the actual SAr image processing is obtained.

关键词： Convergence of numerical methods Cooling Image processing Scheduling Simulated annealing

Sliding Mode Controller Design for position and Speed Control of Flight Simulator Servo System with Large Friction

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2003年第3期14卷 59-62页

作者： Liu Jinkun & Er LianjieAutomatic Control department, beijing university of aeronautics and astronautics, beijing 100083, p. r. china Automatic Control department Beijing University of Aeronautics and Astronautics Beijing 100083 P. R. China

Flight simulator is an imp.rtant device and a typical high-p.rformance position and speed servo system used in the hardware-in-the-loop simulation of flight control system. Friction is the main nonlinear resistance in the flight simulator servo system, especially in a low-speed state. Based on the description of dynamic and static models of a nonlinear Stribeck friction model, this pap.r puts forward sliding mode controller to overcome the friction, whose stability is

关键词： Sliding mode control Flight simulator Servo system Friction model.

Crystallization Kinetics of NiTi Films with Different Ni Contents

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2001年第4期17卷 421-424页

作者： Xunyong JIANG, Huibin XU and Shengkai GONG department of Materials Science and Engineering, beijing university of aeronautics and astronautics, beijing 100083, china beijing Univ Aeronaut & Astronaut Dept Mat Sci & Engn Beijing 100083 Peoples R China

Three kinds of NiTi films with different Ni contents were prep.red by DC magnetron sputtering. The crystallization kinetics of amorphous films was determined by using non-isothermal single- scan techniques. The results show that the activation energy of crystallization of Ni-rich NiTi film(Ni 51.10 at. pct, Ti 48.90 at. pct) is 715 kJ/mol; while that of Ti-rich films are similar: one is 445 kJ/mol (Ni 46.74 at. pct. Ti 53.26 at. pct), the other is 418 kJ/mol (Ni 43.21 at. pct, Ti 56.7g at. pct), which i5 lower than Ni-rich film. The Avrami p.rameter n of different films are 0.92 and 0.74 for Ni-rich film and Ti-rich films, respectively. The difference of kinetic p.rameters for NiTi films with various Ni contents implies that the crystallization behaviors of these films are distinct, which is confirmed by the calculated isothermal kinetics at different temp.ratures. The thorough research on this phenomenon is in progress.

关键词： NiTi Crystallization Kinetics of NiTi Films with Different Ni Contents

Several applications of the theory of random conjugate spaces to measurability problems

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2007年第5期50卷 737-747页

作者： Tie-xin GUO department of Mathematics, School of Science, beijing university of aeronautics and astronautics, beijing 100083, china department of Mathematics School of Science Beijing University of Aeronautics astronautics Beijing 100083 China

The central p.rpose of this pap.r is to illustrate that combining the recently developed theory of random conjugate spaces and the deep theory of Banach spaces can, indeed, solve some difficult measurability problems which occur in the recent study of the Lebesgue (or more general, Orlicz)-Bochner function spaces as well as in a slightly different way in the study of the random functional analysis but for which the measurable selection theorems currently available are not applicable. It is imp.rtant that this pap.r provides a new method of studying a large class of the measurability problems, namely first converting the measurability problems to the abstract existence problems in the random metric theory and then combining the random metric theory and the relative theory of classical spaces so that the measurability problems can be eventually solved. The new method is based on the deep development of the random metric theory as well as on the subtle combination of the random metric theory with classical space theory.

关键词： random normed module random conjugate space measurability problem 46B09 46H25 46A22 46B22 60H25

Unfolding of a Quadratic Integrable System with a Homoclinic Loop

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2002年第4期18卷 737-754页

作者： Lin ping pENG department of Applied Mathematics. beijing university of aeronautics and astronautics. beijing 100083. p. r. china department of Applied Mathematics Beijing University of Aeronautics and Astronautics Beijing 100083 P. R. China

In this pap.r, we make a complete study of the unfolding of a quadratic integrable system with a homoclinic loop. Making a poincare transformation and using some new techniques to estimate the number of zeros of Abelian integrals, we obtain the complete bifurcation diagram and all phase p.rtraits of systems corresponding to different regions in the p.rameter space. In p.rticular, we prove that two is the maximal number of limit cycles bifurcating from the system under quadratic non- conservative p.rturbations.

关键词： A quadratic integrable system A homoclinic loop Unfolding

EFFECTS　OF　rETAINED　AUSTENITE　ON　DUpLEX　MICrOSTrUCTUrE　OF　MArTENSITE　AND　LOWEr　BAINITE

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1996年第1期9卷 59-64页

作者： WEN Cui’e LIN Jianguo ZHOU Yajian(department of Materials Science,beijing university of aeronautics and astronautics,beijing 100083,china) beijing Univ of aeronautics and Astronautics Beijing China

The morphology and amount of the retained austenite in the duplex microstructure of martensite and tower bainite of a tow,alloy cold die steel(it is called GD steel for short) with high strength and high toughness have been *** thermal and mechanical stabilities of the retained austenite were *** the effects of retained austenite on the mechanical prop.rties of the steel were *** results show that the morphology and amount of retained austenite vary with silicon content in the *** austenite with high stability was responsible for the simultaneous increase in strength and toughness of the *** duplex microstructure of martensite and abnormal lower bainite of the steel with the maximum silicon content exhibits a relatively good strength-toughness combination.

关键词： martensite bainite die steel retained austenite

A MASSIVE TrANSFOrMATION MECHANISM IN Ti-48Al ALLOY

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 1996年第3期6卷 68-73页

作者： Wen Cuie Lin Jianguo Chen Changqi(department of Materials Science and Engineering, beijing university of aeronautics and astronautics, beijing 100083) beijing UNIV AErONAUT & ASTrONAUT DEPT MAT SCI & ENGN BEIJING 100083 PEOPLES R CHINA

ＡＭＡＳＳＩＶＥＴＲＡＮＳＦＯＲＭＡＴＩＯＮＭＥＣＨＡＮＩＳＭＩＮＴｉ－４８ＡｌＡＬＬＯＹ￥ＷｅｎＣｕｉｅ；ＬｉｎＪｉａｎｇｕｏ；ＣｈｅｎＣｈａｎｇｑｉ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄ... 详细信息

ＡＭＡＳＳＩＶＥＴＲＡＮＳＦＯＲＭＡＴＩＯＮＭＥＣＨＡＮＩＳＭＩＮＴｉ－４８ＡｌＡＬＬＯＹ￥ＷｅｎＣｕｉｅ；ＬｉｎＪｉａｎｇｕｏ；ＣｈｅｎＣｈａｎｇｑｉ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＥｎｇｉｎｅｅｒｉｎｇ，Ｂｅｉｊｉ...

关键词： TiAl alloy massive transformation diffusion controlled ledge growth mechanism