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The characteristics of arc beam shaping in hybrid plasma and laser deposition manufacturing

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Science China(Technological Sciences) 2006年第2期49卷 238-247页

作者： ZHANG Hai’ou1, QIAN Yingping1,3. WANG Guilan1 & ZHENG Qiguang2 1. School of Material Science and technology, Huazhong university of Science and technology, Wuhan 43.074, China 2. Institute of Laser technology and engineering, Huazhong university of Science and technology, Wuhan 43.074, China 3. mechanical engineering college, Hubei university of technology, Wuhan 43.068, China 1. School of Material Science and technology Huazhong University of Science and Technology Wuhan 430074 China 3. mechanical engineering college Hubei University of Technology Wuhan 430068 China 2. Institute of Laser technology and engineering Huazhong University of Science and Technology Wuhan 430074 China

As a new direct metal prototyping technology,the hybrid plasma and laser deposition manufacturing (PLDM) is proposed in this paper. In order to figure out the characteristics of plasma arc beam and mould in the PLDM process of high temperature alloy, the high speed CCD camera is used to obtain the picture around the plasma arc. Afterwards the sketch of picture is clearly obtained. And the effect of laser parameter, such as average power, pulse width, pulse repetition frequency and the angle between laser beam and plasma arc beam on the plasma arc appearance, is studied experimentally. The results show that the modality of plasma arc beam is markedly influenced by laser beam. And the improvements of shape precision and surface state of the layer deposited by PLDM are confirmed.

关键词： plasma hybrid laser, direct deposition, plasma arc beam, molding character, high-temperature alloy.

A mechanical MODEL FOR THE CHIP SIDE DEFORMATION IN ALUMINIUM ALLOY CUTTING

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中国有色金属学会会刊：英文版 1995年第4期5卷 168-172页

作者： Xia Wei Li Yuanyuan Zhou Zehua(Department of mechanical engineering,south China {3. of technology,guangzhou 510641) south China Univ of technology Guangzhou China

ＡＭＥＣＨＡＮＩＣＡＬＭＯＤＥＬＦＯＲＴＨＥＣＨＩＰＳＩＤＥＤＥＦＯＲＭＡＴＩＯＮＩＮＡＬＵＭＩＮＩＵＭＡＬＬＯＹＣＵＴＴＩＮＧＸｉａＷｅｉ；ＬｉＹｕａｎｙｕａｎ；ＺｈｏｕＺｅｈｕａ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈ... 详细信息

ＡＭＥＣＨＡＮＩＣＡＬＭＯＤＥＬＦＯＲＴＨＥＣＨＩＰＳＩＤＥＤＥＦＯＲＭＡＴＩＯＮＩＮＡＬＵＭＩＮＩＵＭＡＬＬＯＹＣＵＴＴＩＮＧＸｉａＷｅｉ；ＬｉＹｕａｎｙｕａｎ；ＺｈｏｕＺｅｈｕａ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ...

关键词： metal cutting mechanical model cutting force chip side deformation

DIMPLE FORMATION ON FRACTURE SURFACE OF STEEL 55SiMnMo

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Acta Metallurgica Sinica(English Letters) 1993年第2期6卷 140-143页

作者： LIANG Sizu LIANG Yaoneng LIU Zhengyi south China university of technology,{3.,China Lecturer,Department of mechanical engineering No.2,south China university of technology,{3. 510641,China south China Univ of technology Guangzhou China

The fracture surface of the normalized steel 55SiMnMo was observed,under tensile device at- tached on the SEM,to be of ductile dimple feature on the bainite which is composed of lath ferrite and austenite *** dimple is essentially nucleated in the *** the austenitic plastic deformation is remarkable during fracturing,the tear ridge of dimple is very sharp.

关键词： dimple plastic deformation ductile fracture steel 55SiMnMo

A MECHANICS MODEL FOR CIRCULAR FORM TOOL CUTTING

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中国有色金属学会会刊：英文版 1996年第2期6卷 86-90,94页

作者： Xia Wei Li Yuanyuan Zhou Zehua (Department of mechanical engineering,south China {3. of technology, guangzhou 510641) S CHINA UNIV TECHNOL DEPT MECH ENGNGUANGZHOU 510641PEOPLES R CHINA

ＡＭＥＣＨＡＮＩＣＳＭＯＤＥＬＦＯＲＣＩＲＣＵＬＡＲＦＯＲＭＴＯＯＬＣＵＴＴＩＮＧＸｉａＷｅｉ；ＬｉＹｕａｎｙｕａｎ；ＺｈｏｕＺｅｈｕａ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ，Ｓｏｕｔｈ... 详细信息

ＡＭＥＣＨＡＮＩＣＳＭＯＤＥＬＦＯＲＣＩＲＣＵＬＡＲＦＯＲＭＴＯＯＬＣＵＴＴＩＮＧＸｉａＷｅｉ；ＬｉＹｕａｎｙｕａｎ；ＺｈｏｕＺｅｈｕａ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ，ＳｏｕｔｈＣｈｉｎａＵｎｉｖｅｒｓｉｔｙｏｆ...

关键词： metal cutting mechanical medel circular form tcol

Microstructure and formation mechanism of twins of laths of austenite with high nitrogen

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Science China(Technological Sciences) 2007年第6期50卷 755-764页

作者： WU CuiLan1,2 & LUO ChengPing2 1 Center for High Resolution Electron Microscopy, college of Materials Science and engineering, Hunan university, Changsha 410082, China {3., south China university of technology, guangzhou 510641, China 1. Center for High Resolution Electron Microscopy College of Materials Science and Engineering Hunan University Changsha 410082 China 2. college of mechanical engineering South China University of Technology Guangzhou 510641 China

The microstructure of composite diffusion layer of the nitrided and chromized 0.2% carbon steel is investigated using TEM and EDS. It is found that laths of austenite with high nitrogen (γ N) precipitate from α-ferrite matrix in the deeper zone of the diffusion layer. These γ N laths are all twins, with their {111} twinning planes parallel to the lath axis, thus forming a characteristic "back-to-back" morphology. There are two types of γN lath. The first is a genuinely {111} twin, and γ N and α keep the accurate K-S relationship, and each γ N and α form a sharp and smooth γ N/α inter- face of {3.5}γN//{3.1}α, namely habit plane {3.5}fcc. The second is a pseudo-twin, with micro-twins {111} or faults formed within the two twin components. Localized lattice deformation (relaxation) seems to have occurred at the interfaces of the second type of γ N due to the formation of micro-twins or faults within the twin components. These micro-twins or faults make the orientation relationship (OR) between each of the γN and the α-matrix deviate from the accurate K-S OR, and the OR between two γ N twin components deviate from the genuine {111} twin relation- ship. In addition, the γ N/α interface of the second type of γ N is not as sharp or smooth as that of the first one.

关键词： austenite containing nitrogen, twins, steel 20, nitriding, composite chromizing

Electrochemical Characterization of Surface-modified LiMn_2O_4 Cathode Materials for Li-ion Batteries

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Journal of Wuhan university of technology(Materials Science) 2006年第4期21卷 56-59页

作者：禹筱元 college of Science South China Agricultural University Guangzhou 510642ChinaSchool of Physics & Engineering Sun Yat-sen University Guangzhou 510275China

To improve the performance, the surface of 12Mn2O4 was coated with very fine MgO , Al2O3.and ZnO by solgel method, respectively. The structure and morphology of the coated materials were investigated by X-ray diffraction （ XRD ）, X-ray photoelectron spectroscopy （ XPS ） and scanning electron microscopy （SEM）. The charge and discharge performance of uncoated and surfnce modified 12Mn2O4 spinel at 25℃ and 55 ℃ were tested, using a voltage window of 3.0-4.3. V and a current deasity of 0. 1 C rate. There is a slight decrease in the initial discharge capacity relative to that of uncoated UMn2 O4, bat the cycle ability of 12 12Mn2O4 coated by metal-oxide has remarkably been improved. The EIS measuremeuts of uncoated and Al2O3.-coated 12Mn2O4 were carried out by a model 273.A potentiostatl galvanistat controUed by a computer using M270 software, and using a freqnency response analyzer （ Zsimpwin ） combined with a potentiostate （ PAR 273.. Coaseqnently, the reason for the improved cycle properties is that the surface modification reduces the dissolution of Mn , which results from the suppression of the electrolyte decomposition, and suppresses the formation of passivation film that acts as an electronic insulating layer. In conclusion, the use of surface modification is an effective way to improve the electrochemical performance of 12Mn2O4 cathode material for lithium batteries.

关键词： lithium-ion batteries surface modification metal-oxide coating: 12Mn2O4 cathode

Parameter identification theory of a complex model based on global optimization method

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Science China(Physics,Mechanics & Astronomy) 2008年第11期51卷 1722-1732页

作者： QU Jie1, JIN QuanLin2 & XU BingYe3.1 college of Automotive engineering, south China {3. of technology, guangzhou 510640, China 2 Beijing Research Institute of mechanical and Electrical technology, Beijing 100083. China 3.Department of engineering Mechanics, Tsinghua {3., Beijing 100084, China 1. college of Automotive engineering South China University of Technology Guangzhou 510640 China 2. Beijing Research Institute of mechanical and Electrical technology Beijing 100083 China 3. Department of engineering Mechanics Tsinghua University Beijing 100084 China

With the development of computer technology and numerical simulation technology, computer aided engineering (CAE) technology has been widely applied to many fields. One of the main obstacles, which hinder the further application of CAE technology, is how to successfully identify the parameters of the selected model. An elementary framework for parameter identification of a complex model is provided in this paper. The framework includes the construction of objective function, the design of the optimization method and the evaluation of the identified results, etc. The parameter identification process is described in this framework, taking the parameter identification of the superplastic constitutive model considering grain growth for Ti-6Al-4V at 927°C as an example. The objective function is the weighted quadratic sums of the difference between the experimental and computational data for the stress-strain relationship and the grain growth relationship; the designed optimization method is a hybrid global optimization method, which is based on the feature of the objective function and incorporates the strengths of genetic algorithm (GA), the Levenberg-Marquardt algorithm and the augmented Gauss-Newton algorithm. The reliability evaluation of parameter identification result is made through the comparison between the calculated and experimental results and between the theoretical values of the parameters and the identified ones.

关键词： constitutive model parameter identification theory inverse analysis global optimization

Vector bundle constraint for particle swarm optimization and its application to active contour modeling

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Progress in Natural Science:Materials International 2007年第10期17卷 1220-1225页

作者： Zeng Delu, Zhou Zhiheng and Xie Shengli(college of Electronic and Information engineering, south China {3. of technology, guangzhou 510641, China) college of Electronic and Information engineering South China University of Technology Guangzhou 510641 China

Active contour modeling (ACM) has been shown to be a powerful method in object boundary extraction. In this paper, a new ACM based on vector bundle constraint for particle swarm optimization (VBCPSO-ACM) is proposed. Different from the traditional particle swarm optimization (PSO), in the process of velocity update, a vector bundle is predefined for each particle and velocity update of the particle is restricted to its bundle. Applying this idea to ACM, control points on the contour are treated as particles in PSO and the evolution of the contour is driven by the particles. Meanwhile, global searching is shifted to local searching in ACM by decreasing the number of neighbors and inertia. In addition, the addition and deletion of particles on the active contour make this new model possible for representing the real boundaries more precisely. The proposed VBCPSO-ACM can avoid self-intersection during contour evolving and also extract inhomogeneous boundaries. The simulation results proved its great performance in performing contour extraction.

关键词： boundary extraction active contour modeling particle swarm optimization velocity update vector bundle.

Regulation of eight avr genes by hrpG and hrpX in Xanthomonas campestris pv. campestris and their role in pathogenicity

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Progress in Natural Science:Materials International 2006年第12期16卷 1288-1294页

作者： XU Rongqi~ 1,3., LI Xianzhen~3. WEI Hongyu~3. JIANG Bole~2, LI Kai~3. HE Yongqiang~ 2,3., FENG Jiaxun~ 1,3.and TANG Jiliang~ 1,2 **(1. Guangxi Key Laboratory of Subtropical Bioresources Conservation and Utilization 2. The Key Laboratory of Ministry of Education for Microbial and Plant Genetic engineering 3. college of Life Science and technology, Guangxi {3., Nanning 53.004, China) Guangxi Key Laboratory of Subtropical Bioresources Conservation and Utilization Guangxi University Nanning 530004 China college of Life Science and technology Guangxi University Nanning 530004 China The Key Laboratory of Ministry of Education for Microbial and Plant Genetic engineering Guangxi University Nanning 530004 China

Eight putative avirulence genes in Xanthomonas campestris pv. campestris (Xcc) strain 8004 were characterized by Tn5gusA5 mutagenesis and gene expression analysis. The virulence test of mutants on Chinese radish showed that all mutants in individual avr genes except avrBs2 mutant were not significantly different from the wild type in virulence. The avrBs2 mutant showed reduced virulence and bacterial growth in planta. Gene expression analysis using β-glucuronidase as reporter indicated that avrBs1.1,avrBs1,avrXccB,avrXccC,avrXccE1 were regulated by hrpG, whereas avrXccA1, avrXccA2 and avrBs2 were not. RT-PCR analysis showed that all hrpG-regulated genes except avrBs1 were also regulated by hrpX. In addition, it was demonstrated that avrBs1 was responsible for elicitation of a type III dependent hypersensitive reaction (HR) on nonhost plant pepper ECW-10R, and wild type Xcc 8004 was unable to cause HR on pepper ECW-20R.

关键词： Xanthomonas campestris pv. campestris avirulence gene virulence expression analysis.