检索结果-南通市图书馆

Journal of Rare Earths 2001年第2期19卷 142-144页

作者：李楠林艳红 coll. of Res. and Environ. Jilin Agric. Univ. Changchun 130118 China

The neodymium complexes with crosslinked polystyrene containing -CH2SH and -CH2SOCH3 groups, P-CH2SH . NdCl3 and P-CH2SOCH3. NdCl3, were prepared. P-CH2SH . NdCl3 shows no catalytic activity for butadiene polymerization, while P-CH2SOCH3. NdCl3 can catalyze the polymerization of butadiene. The content of cis-1,4-polybutadiene is more than 95%.

关键词： rare earths polymer-supported neodymium complex butadiene polymerization catalyst

Parameter selection of support vector machine for function approximation based on chaos optimization

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2008年第1期19卷 191-197页

作者： Yuan Xiaofang Wang Yaonan coll. of Electrical & Information Engineering Hunan Univ. Changsha 410082 P. R. China

The support vector machine （SVM） is a novel machine learning method, which has the ability to approximate nonlinear functions with arbitrary accuracy. Setting parameters well is very crucial for SVM learning results and generalization ability, and now there is no systematic, general method for parameter selection. In this article, the SVM parameter selection for function approximation is regarded as a compound optimization problem and a mutative scale chaos optimization algorithm is employed to search for optimal paraxneter values. The chaos optimization algorithm is an effective way for global optimal and the mutative scale chaos algorithm could improve the search efficiency and accuracy. Several simulation examples show the sensitivity of the SVM parameters and demonstrate the superiority of this proposed method for nonlinear function approximation.

关键词： learning systems support vector machines (SVM) approximation theory parameter selection optimization.

Heat transfer analysis for the roller shell under the condition of periodic thermal shock

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2003年第6期10卷 44-47页

作者： Lihua Zhan and Xiaoqian Licoll.ge of Electro-mechanical Engineering, Central South University, Changsha 410083, China coll. of Electro-Mech. Eng. Central South Univ. Changsha 410083 China

According to the actual working conditions of roller shell in the process ofcontinuous roll casting, the Fourier heat transfer law is used to conduct the simulating analysisfor the temperature distribution of the roller shell under the condition of periodic thermal *** temperature variation law inside the roller shell is studied during the process of continuousroll casting, and the steady temperature distributions of the roller shell at different castingvelocities have been obtained when the thermal contact conductance between the roller shell and thecasting strip is considered.

关键词： roller shell thermal contact conductance (TCC) periodic thermal shock

Delay-dependent state feedback robust stabilization for uncertain singular time-delay systems

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2008年第4期19卷 758-765页

作者： Gao Huanli Xu Bugong coll. of Automation South China Univ. of Technology Guangzhou 510640 P. R. China

The problem of robust stabilization for uncertain singular time-delay systems is studied. First, a new delay-dependent asymptotic stability criteria for normal singular time-delay systems is given, which is less conservative. Using this result, the problem of state feedback robust stabilization for uncertain singular time-delay systems is discussed, Finally, two examples are given to illustrate the effectiveness of the results.

关键词： singular systems time-delay delay-dependent robust stabilization linear matrix inequalities(LMIs)

Effective method for tracking multiple objects in real-time visual surveillance systems

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2009年第6期20卷 1167-1178页

作者： Wang Yaonan Wan Qin Yu Hongshan coll. of Electrical and Information Engineering Hunan Univ. Changsha 410082 P. R. China

An object model-based tracking method is useful for tracking multiple objects, but the main difficulties are modeling objects reliably and tracking objects via models in successive frames. An effective tracking method using the object models is proposed to track multiple objects in a real-time visual surveillance system. Firstly, for detecting objects, an adaptive kernel density estimation method is utilized, which uses an adaptive bandwidth and features combining colour and gradient. Secondly, some models of objects are built for describing motion, shape and colour features. Then, a matching matrix is formed to analyze tracking situations. If objects are tracked under occlusions, the optimal ＂visual＂ object is found to represent the occluded object, and the posterior probability of pixel is used to determine which pixel is utilized for updating object models. Extensive experiments show that this method improves the accuracy and validity of tracking objects even under occlusions and is used in real-time visual surveillance systems.

关键词： visual surveillance multiple object tracking object model matching matrix.

Thermodynamics of Modifying Effect of Rare Earth Oxide on Inclusions in Hardfacing Metal of Medium-High Carbon Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2002年第4期20卷 291-294页

作者：赵研辉李艳丽姚枚杨庆祥 coll. of Mat. Sci. and Eng. Yanshan Univ. Qinhuangdao 066004 China

The modifying effect of rare earth (RE) oxide on inclusions in hardfacing metals of medium-high carbon steel was investigated by means of thermodynamics. The thermodynamic analysis for inclusion formation shows that RE oxide can be reduced to RE element by carbon, then the RE element can react with oxygen and sulfur to form the RE oxide, RE sulfide and RE oxide-sulfide in hardfacing molten pool. The deoxidization and the desulphurization can be carried out and the liquid metal can be purified. In addition, RE oxide can also react with sulfur to form RE oxide-sulfide directly. Therefore, the harmful effect of sulfur can be decreased.

关键词： rare earths oxide inclusion hardfacing metal thermodynamics

Data fusion control and guidance of surface-to-air missile under the complex circumstance based on neural-net technology

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2008年第5期19卷 996-1002页

作者： Zhou Deyun Zhou Feng coll. of Electronic Communication Northwestern Polytechnical Univ. Xi'an 710072 P. R. China

Under the complicated electromagnetism circumstance, the model of data fusion control and guidance of surface-to-air missile weapon systems is established. Such ways and theories as Elman-NN, radar tracking and filter＇s data fusion net based on the group method for data-processing （GMRDF） are applied to constructing the model of data fusion. The highly reliable state estimation of the tracking targets and the improvement in accuracy of control and guidance are obtained. The purpose is optimization design of data fusion control and guidance of surface-to-air missile weapon systems and improving the fighting effectiveness of surface-to-air missile weapon systems.

关键词： surface-to-air missile fusion neural net GMDH control and guidance.

Entrapment of Inclusions in Diamond Crystals Grown from Fe-Ni-C System

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2002年第2期18卷 171-172页

作者： Yuxian LIU, Limei XIAO and Longwei YINcoll.ge of Materials Science and Engineering, Shandong University, Jinan 250061, China [ Manuscript received June 28, 2001, in revised form October 18, 2001] coll. of Mat. Sci. and Eng. Shandong Univ. Jinan 250061 China

Diamond single crystals grown from Fe-Ni-C system at high temperature-high pressure (HPHT) usually contain inclusions related to the metallic catalyst. During the diamond growth, the metallic inclusions are trapped by the growth front or are formed through reaction between the contaminants trapped in the diamond. In the present paper, the metallic inclusions related to the catalyst were systematically examined by transmission electron microscopy (TEM). The chemical composition and crystal structure of the metallic inclusions were for the first time determined by selected area electron diffraction pattern (SADP) combined with energy dispersive X-ray spectrometry (EDS). It is shown that the inclusions are mainly composed of orthorhombic FeSi2, fcc (FeNi)23C6, and orthorhombic Fe3C, hexagonal Ni3C.

关键词： Synthetic diamond Fe-Ni-C system Inclusion Transmission electron microscopy

Effect of Deformation Condition on Axial Compressive Precision Forming Process of Tube with Curling Die

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1期17卷 135-136页

作者： He YANG and Zhichao SUN coll.ge of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072, China coll. of Mater. Sci. Northwestern Polytechnol. Univ. Xi'an 710072 China

The effect of the deformation condition on the axial compressive precision forming process of tube with curling die was investigated by using a rigid-plastic FEM. The results show that the forming accuracy depends mainly on geometric condition rp/d0, little on tube material properties and friction condition; the relative gap △/2rp of double-walled tubes obtained decreases with Increasing rp/d0, and there is a parameter k for a given to/do or rp/t0, when rp/d0 >k, △/2rp1.

关键词： Effect of Deformation Condition on Axial Compressive Precision Forming Process of Tube with Curling Die

Synthesis, Characterization and Activity of Rare Earth Complexes with Schiff Base From 2,6-Diformylpyridine N-Oxide and 4-Amino-antipyrine

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2002年第5期20卷 385-387页

作者：于青唐瑜谭民裕 coll. of Chem. and Chem. Eng. Lanzhou Univ. Lanzhou 730000 China

Six new rare earth complexes with Schiff base from 2,6 diformylpyridine N oxide and 4 amino antipyrine were synthesized. These complexes with general formula REL(NO 3) 3 (RE=La, Pr, Eu, Tb, Er, Y) were character... 详细信息

关键词： rare earths 2,6 diformypyridine N oxide 4 amino antipyrine Schiff base antimicrobial activity