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Effects of NaNbO_3-Co_2O_3 Co-additive on the Properties of PZN-PZT Ceramics

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Journal of Wuhan university of technology(Materials Science) 2007年第4期22卷 722-724页

作者：邓毅华 college of Material Science and engineering South China University of Technology Department of Electronic Science and technology Huazhong University of Science and TechnologyWuhan 430074China

NaNbO3-Co2O3 co-added PZN-PZT （PZCNNT） ceramics were prepared using conventional solid state reaction. The piezoelectric and dielectric properties were measured. The experimental results show that the addition of 0.3mo1% Co2O3 leads to low dielectric loss （tgδ） in PZCNNT ceramics and the proper addition of NaNbO3 not only improves piezoelectric properties but also decreases intensively dielectric loss and mechanical loss. The optimal ceramic having d33=310 pC/N, kp=0.59, εr=985, tgδ=0.0034, Qm=1380 was obtained.

关键词： PZN-PZT piezoelectric constant dielectric constant dielectric loss

TRANSFORMATION OF UPPER BAINITE IN 55SiMnMo STEEL DURING TEMPERING

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Acta Metallurgica Sinica(English Letters) 1990年第2期3卷 138-141页

作者： LIAO Yuyan LIU Zhengyi south china university of technology,guangzhou,china LIAO Yuyan Lecturer,Dept.of mechanical engineering No.2,south china university of technology,guangzhou 510641,china

The transformation of upper bainite of normalized 55SiMnMo steel during tempering has been studied by optical microscopy,X-ray diffraction,transmission electron microscopy and differential scanning *** plate surface is parallel to ferrite{110}and is the coherent interface for α and γ,the crystallographic relationship is(111)_γ,∥(011)_α.The small plate surface of Fe_3C precipitated during tempering is parallel to(100).The strengthening mechanism for carbon-rich austenite in normalized condition is primarily uniform solid so- lution hardening,however,in the tempered state,it is strengthened chiefly by non-uniform one.

关键词： SiMnMo steel bainite transformation

H2 /H∞ control of networked control system with random time delays

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Science china(Information Sciences) 2011年第12期54卷 2635-2650页

作者： QIU Li 1,2 , XU BuGong 1 & LI ShanBin 1 1 college of Automation Science and engineering, south china university of technology, guangzhou 510640, china 2.college of Mechatronics and Control engineering, Shenzhen university, Shenzhen 518060, china 1. college of Automation Science and engineering South China University of Technology Guangzhou 510640 China2. College of Mechatronics and Control Engineering Shenzhen University Shenzhen 518060 China

This paper investigates the H 2 /H ∞ control problem for a class of discrete-time networked control systems with random communication time delays. Both sensor-to-controller (S-C) and controller-to-actuator (C-A) random network-induced delays are considered. Two independent Markov chains are used to model the S-C and C-A random delays. The resulting closed-loop system is a jump linear time-delay system induced by two Markov chains. Sufficient conditions for existence of H 2 /H ∞ controller are established by free-weighting matrix and stochastic Lyapunov functions. A simulation example illustrates the effectiveness of the proposed method.

关键词： H 2 /H ∞ control networked control systems Markov chains random time delays

Evaporative Condensers in Comfortable Air Conditioning System

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湖南大学学报（自然科学版） 2009年第S1期36卷 136-140页

作者： YIN Ying-de1,ZHU Dong-sheng1,DU Gui-mei2,LI Yuan-xi1,SUN He-jing1,LIU Qing-ming1(1.Key Lab of Enhancement Heat Transfer and Energy Conservation,the Ministry of Education,south china university of technology,guangzhou,Guangdong 510641,china 2.college of Civil engineering,Hunan university,Changsha,Hunan 410082,china) Key Lab. of Enhancement Heat Transfer and Energy Conservation South China University of Technology Guangzhou 510641 China college of Civil engineering Hunan University Changsha 410082 China

The operating theory of an evaporative condenser was *** difference between an evaporative condensing refrigeration system and a general refrigeration system was *** with the air-cooled and the water-cooled,the virtues of energy-conservation and water-conservation of evaporative condensers were *** questions existing in the application of evaporative condensers were pointed out,the corresponding solving methods were analyzed accordingly,and the development trend of evaporative condensing technique in mechanical refrigeration system field and the applied foreground of evaporative condensers in comfortable air conditioning were prospected.

关键词： evaporative condensers evaporative condensing refrigeration system general refrigeration system comfortable air conditioning system

EFFECT OF Zr ON PHASE TRANSFORMATION IN Cu-Zn-Al SHAPE MEMORY ALLOYS

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Acta Metallurgica Sinica(English Letters) 1990年第2期3卷 93-98页

作者： XIAO Jichuang FANG Jianneng south china university of technology,guangzhou,china XIAO Jichuang Associate Professor,Dept.of mechanical engineering No.2,south china university of technology,guangzhou 510641,china

An investigation was made of the influence of Zr additive on the high temperature phase trans- formations,martensitic forward/reverse transformations,and shape memory effect of Cu-Zn-Al base alloys by means of differential scanning calorimetry(DSC),X-ray diffraction and *** was found that an addition of 0.35 wt-% Zn could effectively inhibit the precipitation of α and γ phases and hence promote the order-martensitic transformations β_2→DO_3→18RM,thus resulting in a minimum activation energy of the martensitic trans- formation and narrow temperature ranges(M_s-M_f)and(A_s-A_f);the alloy so obtained pos- sessed smooth and mobile martensite intervariant interfaces,therefore showing the best shape memory effect.

关键词： Cu-Zn-Al alloy Zr differential scanning calorimetry phase transformation

Kinetics analysis of volume phase transition of intelligent neutral thermo-sensitive hydrogels

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Science china(Physics,Mechanics & Astronomy) 2008年第5期51卷 532-540页

作者： WANG XiaoGui1 & LI YiQuan2 1 college of mechanical engineering,Zhejiang university of technology,Hangzhou 310032,china 2 School of mechanical & Electronic engineering,Changchun university of Science and technology,Changchun 130022,china 1. college of mechanical engineering Zhejiang University of Technology Hangzhou 310032 China 2. School of mechanical & Electronic engineering Changchun University of Science and Technology Changchun 130022 China

In this work,utilizing the first law of thermodynamics and the Flory mean-field theory,the kinetic deformation studies concerning the volume phase transition of the neutral thermo-sensitive hydrogels were performed *** hydrogel was assumed as a biphasic mixture medium in the framework of the continuum mixture *** the energy conservation of the thermodynamics system of the hydrogel,the governing equations for the kinetics of the nonlinear large deforma-tion were *** explicit analytical expressions of the effective stress tensor and the chemical potential of the fluid of the thermo-sensitive hydrogel PNIPA were also obtained from the Helmholtz free energy,which can model the steady-static volume phase transition quantitatively.

关键词： thermo-sensitive hydrogel volume phase transition effective stress energy conservation

Direct gray-scale extraction of topographic features for vein recognition

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Science china(Information Sciences) 2010年第10期53卷 2062-2074页

作者： KANG WenXiong 1, LI HuaSong 2 & DENG FeiQi 1 1 college of Automation Science and engineering, south china university of technology, guangzhou 510640, china 2 School of Information engineering, Wuyi university, Jiangmen 529000, china 1. college of Automation Science and engineering South China University of Technology Guangzhou 510640 China2. School of Information Engineering Wuyi University Jiangmen 529000 China

Binarization processing is a key step in most vein pattern recognition, but may create flaws such as leakage of some feature information. In order to overcome this problem, a new approach is explored in this paper which can extract topographic features directly from gray-scale vein images without binarization processing. First, an extreme graph of directional fields (EGDF) is calculated according to neighborhood information of every pixel, and then the intravenous main ridge of the image can be separated step by step from EGDF with the defined constraint template sets. After that, the sub-ridge is extracted from end points of the main ridge in range constraint image with the tracing method of maximal neighboring point. According to contrast experiment the proposed method is better than the traditional processing (performing binarization first and then skeletonization), in that it can overcome the problem that some separate vein lines are extracted incorrectly, and it can avoid extracting two neighboring vein lines as one ridge. As such, the proposed method is an effective way to extract topographic features for vein recognition

关键词： vein recognition feature extraction directional fields

MICROSTRUCTURES OF A NOVEL HIGH STRENGTH AND WEAR-RESISTING ZINC ALLOY

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中国有色金属学会会刊：英文版 1995年第4期5卷 84-88,132页

作者： Li Yuanyuan Xia Wei Ngai Tungwai Leo Luo Junming Zheng Lingyi(Department of mechanical engineering,south china university of technology, guangzhou 51064) south china Univ of technology Guangzhou China

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ＭＩＣＲＯＳＴＲＵＣＴＵＲＥＳＯＦＡＮＯＶＥＬＨＩＧＨＳＴＲＥＮＧＴＨＡＮＤＷＥＡＲ－ＲＥＳＩＳＴＩＮＧＺＩＮＣＡＬＬＯＹＬｉＹｕａｎｙｕａｎ；ＸｉａＷｅｉ；ＮｇａｉＴｕｎｇｗａｉＬｅｏ；ＬｕｏＪｕｎｍｉｎｇ；ＺｈｅｎｇＬｉｎｇｙｉ（Ｄｅｐａｒｔｍｅ...

关键词： zinc alloy microstructure strength wear-resistance

PREPARATION AND PROPERTIES OF Ni-Cr AND Fe-Cr-Al FILMS BY VACUUM EVAPORATION

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Acta Metallurgica Sinica(English Letters) 2003年第4期16卷 283-288页

作者： X.W. Shi, Z.Y. Liu, B.C. Zeng and CM. LiInstitute of Materials Science & technology, college of mechanical engineering, south china university of technology, guangzhou 510640, china Institute of Materials Science & technology College of Mechanical Engineering South China University of Technology Guangzhou 510640 China

Ni-Cr and Fe-Cr-Al films deposited on the Al2O3 substrate are studied by a method of vacuum evaporation in this paper. Influence of resistance value on density and evaporation parameters of the films reveals that the resistance of films and the adhesion of films to substrates are determined by the evaporation time and the substrate temperate under the condition of the maximum vacuity of 6.2×10-4 Pa, respectively.

关键词： vacuum evaporation resistance of film vacuity