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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@***) 1. Department of Control science & Control Engineering Huazhong University of Science & Technology 430074 Wuhan China 2. school of automation Wuhan University of Science & Technology 430070 Wuhan China 3. school of Information Central South University of Economy Politics and Law 430064 Wuhan China 4. school of Electronics & Information Engineering South China University of Technology 510640 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 simulations and experimental investigations on transverse effects of two-wave mixing in a photovoltaic photorefractive crystal

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science china(Physics,Mechanics & Astronomy) 2010年第5期53卷 856-863页

作者： CAI Xin1,2.LIU JinSong1 & WANG ShengLie1 1 wuhan National Laboratory for Optoelectronics,school of Optoelectronic {2. and Engineering,Huazhong university of {2. and technology,wuhan 430074,china 2.school of {2.,wuhan university of technology,wuhan 430070,china 1. wuhan National Laboratory for Optoelectronics School of Optoelectronic Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China2. School of Science Wuhan University of Technology Wuhan 430070 China

The transverse effects of two Gauss waves mixing in a photovoltaic photorefractive crystal,i.e.,the dynamical evolutions of signal beam with different parameters,are traced numerically and *** the one-dimensional numerical simulations and two-dimensional experimental investigations show that the self-focusing effect of signal beam becomes more obvious as the intensity of pump beam and the angle between the signal and pump beams *** accordance with these results,the state of two Gaussian waves mixing is controllable.

关键词： numerical simulation experimental investigation two-wave mixing transverse effects Gaussian distribution

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Blank design optimization for stepped-section profile ring rolling

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science china(Technological sciences) 2010年第6期53卷 1612-1619页

作者： QIAN DongSheng & HUA Lin school of Materials science and Engineering,{2. university of technology,{2. 430070,china 1. school of Materials science and Engineering Wuhan University of Technology Wuhan 430070 China

A stepped-section ring consists of two rectangular section rings,a big ring and a small ring,joined *** kind of ring is difficult to process by the ring rolling technique because of its complex cross-sectional *** a reasonable blank design is *** this paper,four blank designs,one is a rectangular cross-section and the other three are stepped-sections with different step volumes,are proposed and compared with each other using theoretical analysis,FE simulation and *** is shown that three of the designs can lead to volume flow from small ring into big ring during rolling,which is disadvantageous for shape formation and dimensional precision;however,the other design may result in good ring shape and high dimensional ***,the optimal blank design is determined to be the one in which the volumes of the big and small rings of the initial blank are equal to those of the final rings,respectively.

关键词： ring rolling stepped-section ring optimization design FE simulation

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Sol-gel Preparation Copper-cadmium Halide DopedPhotochromic Glass Coating on Plate Glass

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International Journal of Minerals,Metallurgy and Materials 2000年第1期14卷 34-37页

作者： ShiyongLuo Jiayun Zhang Jixiang Liu Metallurgy school, university of {2. and technology Beijing, Beijing 100083, china wuhan university of technology, wuhan 430070, china Univ Sci & Technol Beijing Met Sch Beijing 100083 Peoples R China wuhan Univ Technol Wuhan 430070 Peoples R China

Copper-cadmium halide doped photochromic glass coating on plate glass has been prepared by a sol-gel process. The sample shows reversible photochromic effect. The results of X-ray diffraction (XRD) and infrared (IR) spectrum investigations indicate that the photochromic phase of tile coating is CuBr_xCl_(1-x), solid solution, and that the structure network of the coating is connected with the bonds of Si-O-Si, Si-O-B and Si-O-Al.

关键词： photochromic glass coating sol-gel photochromic phase, structure network

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Binding Materials of Dehydrated Phases of Waste Hardened Cement Paste and Pozzolanic Admixture

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Journal of wuhan university of {2.(Materials science) 2009年第1期24卷 140-144页

作者：吕林女 school of science Wuhan University of Technology

Fly ash （FA） and ground granulated blast-furnace slag （GGBFS） were added to improve the performances of regenerated binding materials （RBM） which refer to dehydrated phases with rebinding ability of waste hardened cement paste. Flowability tests, compressive strength tests, SEM, TG-DSC, and non-evaporable water content tests were employed to study the performances of the combined binding materials and the interactions between RBM, FA, and GGBFS. Results show that adding FA or GGBFS can improve the workability of RBM paste, and GGBFS has positive effects on strength of RBM. Pozzolanic reactions happen between RBM, FA, and GGBFS. And the activation effect of RBM to FA and GGBFS is superior to that of P.O grade-32.5 cement, especially at earlier ages, because of the high reactive f-CaO existing in RBM. On the advantages of the synergetic effects of RBM and pozzolanic admixtures such as FA and GGBFS, new combined binding materials can be prepared by blending them together.

关键词： combined binding materials dehydrated phase fly ash granulatedblast-furnace slag

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The Role of Calcium in Microstructural Refinement of AZ91 Magnesium Alloy

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Journal of wuhan university of {2.(Materials science) 2006年第4期21卷 45-47页

作者：刘生发 school of Materials science and Engineering Wuhan University of Technology Wuhan 430070China

The effect of calcium addition on the microstructures of AZ91 magnesium alloy was investigated. It was found that a small amount of calcium in AZ91 allay produced a large decrease in the α- Mg grain size and the dispersed fine β-Mgt7 Alt2.phases. In addition, some Al4Ca particles were found to exist in the AZ91 alloy containing 0.5wt% Ca. EDS analysis and water-quenched technique revealed that the grain-refining mechanism of calcium for the AZ91 alloys was mainly attributed to the role of restricting growth of calcium in the primary α-Mg crystals.

关键词： AZ91 magnesium alloy calcium microstructural refinement

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Synthesis of Cr-Al_2._3 Cermet Selective Surfaces Coated by SnO_2.Thin Film by Air Plasma Spraying

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稀有金属材料与工程 2012年第S1期41卷 272-275页

作者： Zhu Zhenqi,Cheng Xudong,Li Guanglei school of Materials science and {2.,wuhan university of {2.,wuhan 430070,china wuhan Univ Technol State Key Lab Adv Technol Mat Synth & Proc Sch Mat Sci & Technol Wuhan 430070 Peoples R China

High efficient Cr-Al2.3 cermet selective surfaces coated by sol-gel SnO2.thin film for high-temperature application were synthesized by air plasma spraying(APS),followed further heat and polish *** phase composition and micro morphology of coating samples were characterized by X-ray diffractions(XRD),scanning electron microscope(SEM)and roughmeter *** solar absorptance(α)and thermal emittance(ε)were determined by optical spectrum *** results show that Cr-Al2.3 cermet coating has a high absorptivity nearly *** unfortunately,the emissivity of these coatings is nearly 0.50 because of the big thickness and coarse surface prepared by APS ***,once coated SnO2.thin film,the composite coatings exhibit excellent selective absorbing property of α=0.89 and ε=***,SnO2.thin film plays a significant role in decreasing the emissivity of coatings as antireflection *** furthermore,the optical performance shows that more metal content and smooth surface are favorable for the selective absorbing ***,the coatings have excellent bond strength with stainless steel substrate and thermal shock resistance at high temperature.

关键词： selective surfaces SnO2 thin film air plasma spraying

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Flexural-tensile Properties of Layered Steel Fiber Reinforced Rubber Concrete

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Journal of wuhan university of {2.(Materials science) 2009年第5期24卷 846-848页

作者：易贤仁 school of sciences Wuhan University of Technology

Layered steel fiber reinforced rubber concrete （LSFRRC）, a new type of pavement concrete based on the requirements of national standard were experimentally researched. The different properties of flexural-tensile strength from plain concrete （PC）, rubber concrete （RC）, layered steel fiber reinforced concrete （LSFRC） and LSFRRC were presented. Experimental results show that the tensile strength of LSFRRC is improved by 4.12. compared with PC, by 13.75% compared with RC. The load-deflection curve on flexural-tensile propertiesis put forward. The flexural-tensile toughness index I10 of LSFRRC is improved 10.32.times compared with PC.

关键词： RC LSFRRC flexural-tensile strength load-deflection curve experimental re-search

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Ferroelectric properties of Bi_(3.4)Ho_(0.6)Ti_3O_(12. thin films prepared by sol-gel method

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science china(Technological sciences) 2008年第9期51卷 1439-1444页

作者： FU ChengJu1, HUANG ZhiXiong1, LI Jie2.& GUO DongYun3 1 school of Materials science and {2., wuhan university of {2., wuhan 430070, china 2.school of Mechanical Engineering, Chongqing university of science and {2., Chongqing 400050, china 3 Department of Physics, wuhan university, wuhan 430072. china school of Materials science and {2. Wuhan University of Technology Wuhan 430070 China school of Mechanical Engineering Chongqing University of Science and Technology Chongqing 400050 China Department of Physics Wuhan University Wuhan 430072 China

We have prepared the Ho-substituted bismuth titanate (Bi3.4Ho0.6Ti3O12. BHT) thin films on Pt/Ti/SiO2.Si substrates using sol-gel method. The crystal structure and morphology of the films were characterized using X-ray diffraction and atomic force microscopy. The BHT film shows a single phase of Bi-layered Aurivillius structure and dense microstructure. The 2.r and 2.c of the 600-nm-thick BHT film were 38.4 μC/cm2.and 376.1 kV/cm, respectively at applied electric field 500 kV/cm. The dielectric constant and dielectric loss are about 310 and 0.015 at a frequency of 1 MHz, respectively. The Pr value decreased to 93% of its pre-fatigue values after 4.46×109 switching cycles at 1 MHz frenquency, and the BHT film shows good in-sulating behavior according to the test of leakage current.

关键词： Bi3.4Ho0.6Ti3O12 thin film sol-gel method ferroelectric property fatigue dielectric constant

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Exploring non-equilibrium statistical ensembles

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science Bulletin 2011年第34期56卷 3654-3660页

作者： BI Qiao & LIU Jie Department of Physics, school of science, {2. university of technology, wuhan 430070, china Department of Physics School of Science Wuhan University of Technology

Since Gibbs synthesized a general equilibrium statistical ensemble theory, generalizing the Gibbsian theory to non-equilibrium phenomena has been a dream for some theorists. However, the status of the theory for the non-equilibrium ensemble formalism is not as well established as the Gibbsian ensemble theory. In this work, we explore the formalism behind the non-equilibrium statistical ensemble theory based on the sub-dynamic kinetic equation originating from the Brussels-Austin school and developed further by others. The key is establishing a similarity transformation between Gibbsian ensembles and the sub-dynamic ensemble. Using this way, we study a spin-Boson model with strong coupling. A reduced density operator for the canonical ensemble can be easily obtained and the relevant decoherence-free property is revealed.

关键词： subdynamics statistical ensemble non-equilibrium statistical physics

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