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On the new results of global attractive set and positive invariant set of the Lorenz chaotic system and the applications to chaos control and synchronization

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Science in china(Series F) 2005年第3期48卷 304-321页

作者： LIAO Xiaoxin 1, 2, 3 , FU Yuli 4 & XIE Shengli 4 1. Department of Control Science & Control Engineering, Huazhong University of Science & Technology, Wuhan 430074, china 2. school of automation, Wuhan University of Science & Technology, Wuhan 430070, china 3. school of Information, Central South University of Economy, Politics and Law, Wuhan 430064, china 4. school of Electronics & Information Engineering, South china University of Technology, Guangzhou 510640, china Correspondence should be addressed to Liao Xiaoxin (email: xiaoxin_liao@***) Department of Control Science & Control Engineering Huazhong University of Science & Technology Wuhan China school of automation Wuhan University of Science & Technology Wuhan China school of Information Central South University of Economy Politics and Law Wuhan China school of Electronics & Information Engineering South China University of Technology Guangzhou China

Constructing a family of generalized Lyapunov functions, a new method is proposed to obtain new global attractive set and positive invariant set of the Lorenz chaotic system. The method we proposed greatly simplifies the complex proofs of the two famous estimations presented by the Russian scholar Leonov. Our uniform formula can derive a series of the new estimations. Employing the idea of intersection in set theory, we extract a new Leonov formula-like estimation from the family of the estimations. With our method and the new estimation, one can confirm that there are no equilibrium, periodic solutions, almost periodic motions, wandering motions or other chaotic attractors outside the global attractive set. The Lorenz butterfly-like singular attractors are located in the global attractive set only. This result is applied to the chaos control and chaos synchronization. Some feedback control laws are obtained to guarantee that all the trajectories of the Lorenz systems track a periodic solution, or globally stabilize an unstable (or locally stable but not globally asymptotically stable) equilibrium. Further, some new global exponential chaos synchronization results are presented. Our new method and the new results are expected to be applied in real secure communication systems.

关键词： Lorenz chaotic system global attractive set positive invariant set globally exponential tracking globally exponential synchronization.

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Numerical Simulation of Transient Thermal Stress Field for Laser Metal Deposition Shaping

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武汉理工大学学报 2006年第S3期28卷 1025-1030页

作者： LONG Risheng~(1,2) LIU Weijun~1 (1.Advanced Manufacture Lab,Shenyang Institute of automation,Shenyang 110016,china 2.Graduate school,Chinese Academy or Sciences,Beijing 100039,china) Advanced Manufacture Lab Shenyang Institute of AutomationShenyang 110016China Graduate school Chinese Academy of SciencesBeijing 100039China Advanced Manufacture Lab Shenyang Institute of AutomationShenyang 110016China

To decrease thermal stress during laser metal deposition shaping(LMDS)process,it is of great importance to learn the transient thermal stress distribution *** on the“element life and death”technique of finite element analy- sis(FEA),a three-dimensional multi-track and multi-layer numerical simulation model for LMDS is developed with ANSYS parametric design language(APDL)for the first time,in which long-edge parallel reciprocating scanning paths is introduced. Through the model,detailed simulations of thermal stress during whole metal cladding process are conducted,the generation and distribution regularities of thermal stress are also discussed in *** the same process parameters,the simulation results show good agreement with the features of samples which fabricated by LMDS.

关键词： LMDS FEA transient thermal stress field numerical simulation

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Power system transient stability simulation based on module bi-directional iteration

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Science china Technological Sciences 2005年第5期 107-122页

作者： FANG Dazhong & YANG Xiaodong school of electrical Engineering & automation, Tianjin University, Tianjin 300072, china

A new simultaneous solution method using module bi-directional iteration is proposed for power system transient stability simulation. In this method, power network is partitioned into a tree hierarchy; computation modules are established for decomposed power networks and various power system components respectively. Through representing every computation module by a computation node, a computation tree is constructed by connecting the nodes together according to their electrical relations in power systems. A tree-traversing procedure called forward reduction and backward evaluation is performed to calculate correction factors of the variables in Newton iterations. This high-efficiency simulation method is feasible to be applied in parallel computation for large interconnected systems. Simulation tests are conducted on the New England 10-generator test power system and the North china-Northeast interconnected system, and the results are compared with those of the commercial software BPA to validate the effectiveness and correctness of this method.

关键词： power system transient stability simulation bi-directional iteration simultaneous solution.

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Tunneling conductance in graphene ferromagnet/p wave superconductor junctions

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Science china(Physics,Mechanics & Astronomy) 2012年第4期Mechanics & Astronomy) .卷 649-653页

作者： LI XiaoWei 1,2*,CHEN HuaBao 1 & LIU ShuJing 1 1 school of Physics and Electronic electrical Engineering,Huaiyin Normal University,Huaian 223300,china 2 State Key Laboratory of Functional Materials for Informatics,Shanghai Institute of Microsystem and Information Technology,Chinese Academy of Sciences,Shanghai 200050,china school of Physics and Electronic electrical Engineering Huaiyin Normal University Huaian China State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai China

Using the extended Blonder-Tinkham-Klapwijk formalism,we investigate the conductance spectra of graphene ferromagnet/p wave superconductor *** is found that the conductance spectra are affected by the p wave pairing *** ferromagnetic exchange energy in the ferromagnet can suppress Andreev retroreflection but enhance the specular Andreev reflection in graphene ferromagnet/p wave superconductor *** conductance decreases with increasing exchange energy Eh for EhEF.

关键词： graphene ferromagnet p wave superconductor tunneling conductance

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Preparation and Property of Chromium Carbide Thermal Diffusion Coating on Cold Working Die Materials

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Journal of Wuhan University of Technology(Materials Science) 2010年第4期25卷 596-599页

作者：袁志华 school of electrical and Mechanical Engineering North University of China school of Equipment Engineering Shenyang Ligong University

Thermal diffusion （TD） salt bath chromizing of cold working dies was studied. Firstly, it obtained an ideal salt bath formula by comparing with a variety of formulas, and then obtained the influence rule of coating thickness based on studying of some process parameters. The microstructure morphologies and phase structures of the TD chromizing coating were investigated by X-ray diffraction （XRD）, energy-dispersive spectrometry （EDS） and other modern analysis methods. Meanwhile, it carried out a system of testing and analysis of coating, such as hardness, wear resistance, etc.

关键词： chromium carbide coating thermal diffusion process cold working die preparation SEM EDS

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Application of Two-Order Difference to Gap Statistic

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Transactions of Tianjin University 2008年第3期14卷 217-221页

作者：岳士弘王秀秀魏苗苗 school of electrical Engineering and automation Tianjin University

Gap statistic is a well-known index of clustering validity, but its realization is difficult to be comprehended and accurately determined. A direct method is presented to improve the performance of the Gap statistic, which applies the two-order difference of within-cluster dispersion to replace the constructed null reference distribution in the Gap statistic. Hence, the realization of the Gap statistic becomes easy and is reformulated, and its uncertainty in applications is reduced. Also, the limitation of the Gap statistic is analyzed by two typical examples, that is, the Gap statistic is difficult to be applied to the dataset that contains strong-overlap or uneven-density clusters. Experiments verify the usefulness of the proposed method.

关键词： clustering validity Gap statistic data structure

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A new approach based on PSO algorithm to find good computational encoding sequences

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Progress in Natural Science:Materials International 2007年第6期17卷 712-716页

作者： Cui Guangzhao1, Niu Yunyun1, Wang Yanfeng1, Zhang Xuncai2 and Pan Linqiang2(1. school of electrical and Electronic Engineering, Zhengzhou University of Light Industry, Zhengzhou 450002, china 2. Research Institute of Biomolecular Computer, Huazhong University of Science and Technology, Wuhan 430074, china) school of electrical and Electronic Engineering Zhengzhou University of Light Industry Zhengzhou 450002 China Research Institute of Biomolecular Computer Huazhong University of Science and Technology Wuhan 430074 China

Computational encoding DNA sequence design is one of the most important steps in molecular computation. A lot of research work has been done to design reliable sequence library. A revised method based on the support system developed by Tanaka et al. is proposed here with different criteria to construct fitness function. Then we adapt particle swarm optimization (PSO) algorithm to our encoding problem. By using the new algorithm, a set of sequences with good quality is generated. The result also shows that our PSO-based approach could rapidly converge at the minimum level for an output of the simulation model. The celerity of the algorithm fits our requirements.

关键词： DNA computing computational encoding DNA sequences PSO algorithm fitness function

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Modeling of human colonic blood flow for a novel artificial anal sphincter system

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2008年第9期9卷 734-738页

作者： Peng ZAN, Guo-zheng YAN, Hua LIU (school of Electronics, Information and electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, china) school of Electronics Information and Electrical Engineering Shanghai Jiao Tong University Shanghai 200240 China. zanpeng@***

A novel artificial anal sphincter system has been developed to simulate the normal physiology of the human anorectum. With the goal of engineering a safe and reliable device, the model of human colonic blood flow has been built and the relationship between the colonic blood flow rate and the operating occlusion pressure of the anorectum is achieved. The tissue ischemia is analyzed based on constitutive relations for human anorectum. The results suggest that at the planned operating occlusion pressure of less than 4 kPa the artificial anal sphincter should not risk the vascularity of the human colon.

关键词： Incontinence Artificial anal sphincter Colonic blood flow Tissue ischemia

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Magnetic Electrochemical Finishing Machining

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厦门大学学报（自然科学版） 2002年第S1期41卷 34-35页

作者： FANG Jian-cheng 1, JIN Zhu-ji 2, XU Wen-ji 2, SHI Yu-ying 1 (1. College of Mechanical Engineering and automation, HQU, Quanzhou 362011, china 2. school of Mechanical Engineering, DUT, Dalian 116023, china)

How to improve the finishing efficiency and surface roughness have been all along the objective of research in electrochemical polishing. However, the research activity, i.e. during electrochemical polishing, directly introduce the magnetic field to study how the magnetic field influences on the finishing efficiency, quality and the electrochemical process in the field of finishing machining technology, is insufficient. When introducing additional magnetic field in the traditional electrochemical polishing, due to the co-action of Lorentz’ force and electric field force, the ions arriving the machined surface by way of a curvilinear motion result in the electric current density distribution on the surface even more non-uniform, then the dissolving velocity of the peak points or side faces and the diffusion velocity of the product are enhanced, and the forcible agitation is happened on the electrodes surface by magnetic field, the removal rate of peak points are still more greater, and efficiency is also still more higher. Compared with the electrochemical polishing, in the magnetic electrochemical finishing machining, the finishing speed at peak points is higher, but at valley points it is lower, therefore after machining, both the highness at peak points and finishing depth at valley points are smaller, the results are propitious to minish initial wear quantity caused by friction and wear when machined workpiece employing in practice, and increase contact stiffness of workpiece, and from the viewpoint of microcosmic theory, this phenomenon is also of advantage to reduce damage to substrate. It can also be seen from the equation presented in the paper that the track of ionic movement relates to the electrodes gap, potential and magnetic induction intensity and furthermore; under the given conditions, the movement also relate to the electrolyte. it can be inferred that there must be an optimum value in respect of the magnetic induction intensity influencing the effic

关键词： magnetic field electrochemical polishing machining efficiency

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Vanadium Carbide Coating Growth on Die Steel Substrate in Borax Salt Bath

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Journal of Wuhan University of Technology(Materials Science) 2010年第4期25卷 600-603页

作者：王洪福 school of Materials Science and Engineering Wuhan University of Technology school of Mechanical Engineering and automation North University of China

Vanadium pentoxide, borax, boron carbide and sodium fluoride were used to grow vanadium carbide coating on die steel（Cr12, Cr12MoV） surface at 950 ℃ by TD process, which extended the life period of Cr12 and Cr12MoV as punching die. Kinetics of vanadium carbide coating growth was brought forward and verified by comparison of the mathematical model with the experimental results. The thickness of coating was illustrated by SEM. The chemical constituent of coating and remnants were tested by XRD. To increase the thickness, rare earths （FeSiRe23） were added to the borax salt bath. The electronic probe microanalysis （EPMA） revealed that the addition of rare earths could decrease carbon concentration in the coating and increase the depth of vanadium carbide coating.

关键词： vanadium carbide coating TD process punching die rare earths

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