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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 2 College of Mechanical Engineering, 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 {335}γN//{341}α, namely habit plane {335}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

Improvement real time performance of robot pose optic fiber sensor on screw assem blies

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光通信技术 1999年第4期 305-309页

作者： Li Xiufeng,Liu Guixiong (Dept.of Machatronic Engineering,south china university of technology,Guangzhou,510640)

The paper firstly introduces screw direction detecting *** proposes a kind of neural network based parallel arithmetic in order to treat the circumstances of complicated sensing *** arithmetic can greatly enlarge the real time treatment ability of sensors,and is successively applied in the pose rectifying of robot screw flexible assembiles.

关键词： Optic fiber sensors BP network arithmetic Signal real time treatment

Effect of Ni on Mg based hydrogen storage alloy Mg_3Nd

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Rare Metals 2006年第z1期25卷 289-294页

作者： TONG Yanqing OUYANG Liuzhang ZHU Min College of Mechanical Engineering South China University of Technology Guangzhou 510641 China College of Mechanical Engineering South China University of Technology Guangzhou 510641 China College of Mechanical Engineering South China University of Technology Guangzhou 510641 China

Magnesium-neodymium based alloys were prepared by induction melting in an alumina crucible under protection of pure argon atmosphere. XRD patterns show that the as-melted Mg-Nd and Mg3NdNi0.1 diffraction peaks can be excellently indexed with D03 structure (BiF3 type, space group Fm3m). The lattice constant of Mg3Nd phase is 0.7390 nm, which is determined by XRD analysis using Cohen′s extrapolation method. The reversible hydrogen storage capacity reaches 1.95wt.% for Mg3Nd and 2.68wt.% for Mg3NdNi0.1. The desorption of hydrogen takes place at 291 ℃ for Mg3Nd and at 250 ℃ for Mg3NdNi0.1. The alloys could absorb hydrogen at room temperature with rapid hydriding and dehydriding kinetics after only one cycle. The enthalpy (ΔH) and entropy (ΔS) of Mg3Nd-H dehydriding reaction were -68.2 kJ·mol-1 H2 and -0.121 kJ·(K·mol)-1 H2 determined by using van′t Hoff plot according to the pressure-composition-isotherms (P-C-I) curve measured at different temperatures. Hydrogen absorption kinetic property of Mg3NdNi0.1 alloy was also measured at room temperature.

关键词： magnesium hydrogen storage rare earth induction melting

MORPHOLOGY AND CRYSTALLOGRAPHY OF ALLOY NITRIDES IN STEEL 4Cr5MoV1Si(H13)

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Acta Metallurgica Sinica(English Letters) 1991年第3期4卷 182-187页

作者： LUO Chengping(C.P.Luo) ZHAO Fang south china university of technology,Guangzhou,china

A TEM investigation was made on the morphology,orientation relationship and habit plane of three alloy nitrides,namely CrN,VN and Mo_2N simultaneously formed within the diffussional nitrided layers in an H13 steel nitrided at 580℃.It *** that the nitrides were precipitated by continuous clustering and subsequent ordering of both interstitial(N)and substitutional(Cr,V,Mo)solutes on {001} habit plane,and that the observed morphology and crystallography of the nitrides were in good agreement with the predictions from the invariant line stain model proposed for precipitation transformations.

关键词： alloy nitride mixed cluster habit plane invariant line strain

TEM observation of sintered permanent magnetic strontium ferrite

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Rare Metals 2006年第z1期25卷 578-583页

Sintered permanent magnetic strontium ferrites were studied using transmission electron microscopy to investigate the microstructure morphology and its correlation with the magnetic properties. The present study shows that the microstructure of sintered permanent magnetic strontium ferrites is an important parameter in determining their magnetic properties. The microstructure morphology in low-performance ferrite magnet is obviously different from high-performance one. The magnetic properties of sintered permanent strontium ferrite depend strongly on the orientation degree of strong magnetic crystals. The presence of ferric oxide phase in ferrite magnet can deteriorate the magnetic properties. Moreover, proper quantities of crystal defects are beneficial to high coercive force due to the fixing of magnetic domain.

关键词： permanent magnetic strontium ferrite TEM Moiré pattern crystal defect

EFFICIENT POLYMER PHOTOVOLTAIC DEVICES BASED ON POLYMER D-A BLENDS

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Chinese Journal of Polymer Science 2001年第6期19卷 597-602页

作者： Xian-yu Deng Li-ping Zheng Yue-qi Mo Gang Yu Wei Yang Wen-hua Weng Yong Cao Institute of Polymer Optoelectronic Material and Devices, south china university of technology Wuhan 430074, china S china Univ Technol Inst Polymer Optoelect Mat & Devices Guangzhou Guangdong Peoples R China UNIAX Corp Santa Barbara CA 93117 USA

Recent work demonstrated that efficient solar-energy conversion could be achieved in polymer photovoltaic cells (PVCs) based on interpenetrating bi-continuous networks([1,2]). In this paper we present a comprehensive study on improving energy conversion efficiencies of PVCs based on composite films of MEBPPV and fullerene derivatives. Carrier collection efficiency of ca. 30% el/ph and energy conversion efficiency of 3.9% were achieved at 500 nm. At reverse bias of 15 V, the photosensitivity reached 0.8 A/W, corresponding to a quantum efficiency over 100% el/ph. These results suggest that high efficiency photoelectric conversion can be achieved in polymer devices with M-P-M structure. These devices are promising for practical applications such as plastic solar cells and plastic photodetectors.

关键词： photovoltaic cell hetero-junction conjugated polymer fullerene

Fabrication of Ceramic Composites by Directed Metal Oxidation

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Journal of Wuhan university of technology(Materials Science) 2004年第1期19卷 48-50页

作者：周曦亚 south china university of technology

To explain the growth mechanism of Al 2O 3/Al Lanxide composites,the dynamics of the directed oxidation of Al-Mg-Si alloys are *** experimental methods to produce Lanxide composites by directed oxidation of metal melts at high temperatures are *** effect of the processing factors on the microstructures and properties of Al 2O 3/Al composites and enforced Al 2O 3/Al composites is also *** with sintering ceramic composites,the advantages of Lanxide process and Lanxide materials are as following:it is a near net shaped process;the process is very simple;the microstructures and properties of Lanxide materials can be adjusted;and this process can be used to infiltrate ceramic fiber or particle preforms.

关键词： composites ceramic directed oxidation Al 2O 3/Al alloy

Multi-agent Based Modeling of Manufacturing Network

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武汉理工大学学报 2006年第S1期28卷 381-387页

作者： GUO Yuming,SUN Yanming,ZHENG Shixiong (School of Mechanical Engineering,south china university of technology,Guangzhou 510641,china) School of Mechanical Engineering South China University of TechnologyGuangzhou 510641China

An intelligent manufacturing system is modeled currently from the viewpoint of manufacturing applications,and the network platform’s influence to manufacturing applications is not considered adequately. However any bottleneck in service oriented architecture (SOA) for the manufacturing network can affect the agility of the IT environment. In this paper,to achieve a trade-off between manufacturing resources and network resources,the manufacturing network is modeled with multi-agent,in which two kinds of basic elements,the manufacturing application unit and the network carrier of manufacturing information,are presented. And their main characters are described by colored petri net. The manufacturing application model drives the network platform that inversely provides this application model technology supports. The proposed multi-agent system is demonstrated through an example integration scenario involving production plan,resources management and execution subsystems. And the result suggests that analyzing and designing the system architecture of networked manufacturing should give due attention to the operation system as well as manufacturing applications.

关键词： manufacturing network model multi-agent colored petri net SOA

Rate-oriented perceptual image coding using contrast-based quantization

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Chinese Optics Letters 2010年第4期8卷 381-383页

作者：余卫宇田菁 School of Electronic and Information Engineering South China University of Technology School of Electrical and Electronic Engineering Nanyang Technological University

A new image coding approach is proposed by controlling the quantization step via minimizing the perceptual distortions（in terms of image＇s contrast measurement）.The proposed method is a rate-oriented contrast-based approach,which is in contrast to the conventional quality-oriented contrast-based image *** algorithm achieves a higher perceptual quality performance against several methods developed previously.

关键词： Visual communication