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Effect of Annealing on mechanical Properties of TaN Film

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稀有金属材料与工程 2011年第S4期40卷 218-220页

作者： Liu Xing1,2,Ma Guojia1,2,Sun Gang2,Duan Yuping1,Liu Shunhua11School of Material and Engineering,Dalian University of technology,Dalian 116024,china2 Science and technology on Power Beam Processes Laboratory,beijing Aeronautical Manufacturing technology research institute,beijing 100024,china beijing Aeronaut Mfg Technol Res Inst Sci & Technol Power Beam Proc Lab Beijing 100024 Peoples R China Dalian Univ Technol Sch Mat & Engn Dalian 116024 Peoples R China

Tantalum nitride (TaN) films were synthesized on bearing steels and Silicon wafers by Electron Cyclotron Resonance microwave plasma source enhanced DC sputtering and the effects of annealing at different temperature on mechanical properties of TaN films were *** morphology and structure of the films were investigated by scanning electron microscope (SEM),X-ray diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS).The mechanical properties were evaluated using *** results showed that the hardness and modulus of TaN film without annealing presented the maximal value,but which intensely dropped down with the increase of annealing temperature between 423K and 473K,meanwhile structure and combination in the films partially changed,but this phenomenon disappeared beyond the *** is found that annealing is a key factor for altering structure and mechanical properties of TaN film.

关键词： magnetron sputtering TaN film annealing

Improving the fatigue endurance of lead zirconate titanate thin films through PbO interfacial modification

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Rare Metals 2011年第1期30卷 68-71页

作者： LEI Rong REN Yanbo QIAO Lijie GU Hongwei YUE Zhenxing XIE Dan CAO Jiangli institute for Advanced Materials and technology University of Science and Technology Beijing Beijing 100083 China institute of electrical Engineering Chinese Academy of Sciences Beijing 100190 China State Key Laboratory of New Ceramic and Fine Processing Tsinghua University Beijing 100084 China institute of Microelectronics Tsinghua University Beijing 100084 China

The effects of the modification of electrode/ceramic interfaces through a chemical solution deposition-derived PbO buffer layer on the fatigue endurance of lead zirconate titanate（PZT） thin films were *** grain size and the surface roughness of the PZT films increased through PbO interfacial ***,the PZT films with PbO interfacial modification had a better crystallographic structure and no evident secondary phases were *** the remanent polarization and dielectric constant were reduced,the fatigue endurance was *** on the results,the mechanism for the fatigue endurance improvement was discussed.

关键词： ferroelectric thin films fatigue lead zirconate titanate chemical modification lead oxide

A new transient stability margin based on dynamic security region and its applications

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Science china(Technological Sciences) 2008年第6期51卷 751-760页

作者： XUE AnCheng1, 2 & MEI ShengWei1 1 State Key Lab of Power Systems, Department of electrical Engineering, Tsinghua University, beijing 100084, china 2 Key Lab of Systems and Control, institute of Systems Science, Chinese Academy of Sciences, beijing 100190, china 1. State Key Lab of Power Systems Department of Electrical Engineering Tsinghua University Beijing 100084 China 2. Key Lab of Systems and Control Institute of Systems Science Chinese Academy of Sciences Beijing 100190 China

A new transient stability margin is proposed based on a new expression of dynamic security region (DSR) which is developed from the existing expression of DSR. Applications of the DSR based transient stability margin to contingency ranking and screening are discussed. Simulations in the 10-machine 39-bus New England system are performed to show the effectiveness of the proposed DSR based tran-sient stability margin.

关键词： dynamic security region (DSR) transient stability margin contingency screening

In-plane bistatic backward scattering from seabottom with randomly inhomogeneous sediment and rough interface

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Science china(Physics,Mechanics & Astronomy) 2004年第6期47卷 702-716页

作者： PENG Zhaohui1,,ZHOU Jixun1,& ZHANG Renhe1 2 2 1.institute of Acoustics,Chinese Academy of Sciences,beijing 100080,china 2.School of mechanical Engineering,Georgia institute of technology,Atlanta,GA 30332,USA 1. institute of Acoustics Chinese Academy of Sciences 100080 Beijing China 2. School of mechanical Engineering Georgia Institute of Technology 30332 Atlanta GA USA

The in-plane bistatic backward scattering caused by seabottom with random inhomogeneities and rough interface is studied. This work combines the ray tube integral method of Ivakin et al. and the complex-ray/steepest descent method of Hines. For a given incident grazing angle, the theoretical expression can easily be used to calculate scattering strength for different backward scattering angles. (This is essential for modeling shallow water reverberation by the normal mode approach.) The model is tested against published scattering measurements. The frequency/angle dependence of backward scattering and effects of volume inhomogeneity parameters on backward scattering are also discussed.

关键词： in-plane bistatic backward scattering, inhomogeneous sediment, rough interface.

Salient region detection and segmentation for general object recognition and image understanding

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Science china(Information Sciences) 2011年第12期54卷 2481-2490页

作者： HUANG TieJun 1 , TIAN YongHong 1 , LI Jia 2 & YU HaoNan 11 National Engineering Laboratory for Video technology, School of electrical Engineering and Computer Science, Peking University, beijing 100871, china 2 Key Laboratory of Intelligent Information Processing, institute of Computing technology, Chinese Academy of Sciences, beijing 100190, china 1. National Engineering Laboratory for Video technology School of Electrical Engineering and Computer Science Peking University Beijing 100871 China2. Key Laboratory of Intelligent Information Processing Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China

General object recognition and image understanding is recognized as a dramatic goal for computer vision and multimedia retrieval. In spite of the great efforts devoted in the last two decades, it still remains an open problem. In this paper, we propose a selective attention-driven model for general image understanding, named GORIUM (general object recognition and image understanding model). The key idea of our model is to discover recurring visual objects by selective attention modeling and pairwise local invariant features matching on a large image set in an unsupervised manner. Towards this end, it can be formulated as a four-layer bottom-up model, i.e., salient region detection, object segmentation, automatic object discovering and visual dictionary construction. By exploiting multi-task learning methods to model visual saliency simultaneously with the bottom-up and top-down factors, the lowest layer can effectively detect salient objects in an image. The second layer exploits a simple yet effective learning approach to generate two complementary maps from several raw saliency maps, which then can be utilized to segment the salient objects precisely from a complex scene. For the third layer, we have also implemented an unsupervised approach to automatically discover general objects from large image set by pairwise matching with local invariant features. Afterwards, visual dictionary construction can be implemented by using many state-of-the-art algorithms and tools available nowadays.

关键词： object recognition image understanding visual saliency salient object segmentation visual dictionary

Effects of crystallization fractions on mechanical properties of Zr-based metallic glass matrix composites

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Science china(Physics,Mechanics & Astronomy) 2010年第3期53卷 424-429页

作者： QIU ShengBao1,2, YAO KeFu1 & GONG Pan1 1 KLAMPT, Department of mechanical Engineering, Tsinghua University, beijing 100084, china 2 institute of Industry technology, Guangzhou & Chinese Academy of Sciences, Guangzhou 511458, china 1. KLAMPT Department of Mechanical Engineering Tsinghua University Beijing 100084 China2. Institute of Industry Technology Guangzhou & Chinese Academy of Sciences Guangzhou 511458 China

The Zr41Ti14Cu12.5Ni10Be22.5 (at.%) bulk metallic glass composites with various crystallization fractions were prepared by pretreating the bulk metallic glassy samples with pulsing current, and then by isothermal annealing at near initial crystallization temperature for different periods of time. The precipitations and crystallization fractions were studied by X-ray diffraction (XRD) and differential scanning calorimetry (DSC), and their effects on mechanical properties of the composite were studied by microhardness, uniaxial compression test and scanning electron microscopy (SEM). The experimental results show that the primary precipitate is quasicrystalline phase and other metastable phases including Be2Zr, Zr2Cu and FCC would precipitate subsequently. In the initial crystallization process, in which the crystallization fraction increases from 0 to 8.2%, both fracture strength and plastic strain increase, with the maximum plastic strain up to 6.4%. When the crystallization fraction is larger than 8.2%, the fracture strength and the plastic strain decrease sharply. Furthermore, the alloy with low crystallization fraction is fractured by shearing, while for high crystallization fraction it is fractured by splitting and cleavage. The results show that the mechanical properties of the glassy alloy could be optimized by controlling the processing parameters.

关键词： bulk metallic glass pulsing current crystallization fraction plasticity shear band

Thermal , Microstructural and mechanical Coupling Analysis Model for Flatness Change Prediction During Run-Out Table Cooling in Hot Strip Rolling

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Journal of Iron and Steel research International 2012年第9期19卷 43-51页

作者： WANG Xiao-dong 1 , 2 , LI Fei 1 , JIANG Zheng-yi 2 ( 1.Shougang research institute of technology , Shougang Group , beijing 100043 , china 2.Faculty of Engineering , University of Wollongong , Wollongong NSW 2522 , Australia ) [a] Shougang research institute of technology Shougang Group Beijing 100043 China [b] Faculty of Engineering University of Wollongong Wollongong NSW 2522 Australia

Non-uniformity of temperature distribution across strip width direction is the ultimate reason why the flatness defect occurs on the strip after cooling process although the strip is flat at the exit of finishing *** thermal , microstructural and mechanical coupling analysis model for predicting flatness change of steel strip during the run-out table cooling process was established using ABAQUS finite element software.K Esaka phase transformation kinetics model was employed to calculate the phase transformation , and coupled with temperature calculation using the user subroutine program ***-plasticity constitutive equations of steel material , in which conventional elastic and plastic strains , thermal strain , phase transformation strain and transformation induced plastic strain were considered , were derived and programmed in the user subroutine program *** conclusion that flatness of steel strip will develop to edge wave defect under the functions of the differential thermal and microstructural behaviors across strip width during the run-out table cooling procedure was acquired through the analysis results of this *** results of this analysis model agree well with the actual measurements and observation.

关键词： hot rolled strip internal stress phase transformation run-out table cooling flatness

Preparation of insoluble fibroin films and its tensile property

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Chinese Science Bulletin 2004年第10期49卷 1009-1011页

作者： LU Qiang CAO Chuanbao ZHAI Huazhang ZHU Hesun research Center of Material Science, beijing institute of technology,beijing 100081, china Correspondence should be addressed to Cao Chuanbao research Center of Material Science Beijing Institute of Technology Beijing 100081 China

Silk fibroin is becoming a promising biomate-rial because of its excellent biocompatibility. However, theregenerated fibroin is usually soluble in water and its me-chanical properties should be improved. Although manymethods, such as adding other polymers or treating withmethanol, can ameliorate the mechanical properties andinsolubility, the biocompatibility of fibroin is usually dam-aged in these processes. In this article, it is first reported thatthe insoluble fibroin films are directly prepared withoutmethanol treatment. According to the results of Fouriertransform infrared spectroscope (FTIR) and the X-ray dif-fraction (XRD), the amount of IS-sheet conformation in-creased with the increasing of concentration. When fibroinfilms are dried from 15 wt% at 60℃, the films become in-soluble in water. More importantly, The tensile strength andelongation of the insoluble fibroin films dried from 15% so-lution at 60℃ reached 15.9 MPa and 49.4% respectively in the wet state, which is distinctly superior to the fibroin films treated with methanol.

关键词：不可溶蚕丝蛋白薄膜机械性质生物适应性傅立叶变换红外光谱

Study on Microstructure Refinement of Vanadium and Nitrogen Microalloyed Low Carbon Bainitic Steel

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Journal of Iron and Steel research International 2011年第S1期18卷 355-359页

作者： GAO Fei 1,2,WANG Rui-zhen 1,QIAN Tian-cai 2 (1.china Central Iron and Steel research institute,beijing 100081,china 2.Kunming University of Science and technology,Kunming 650093,Yunnan,china) china Cent Iron & Steel Res Inst Beijing 100081 Peoples R China Kunming Univ Sci & Technol Kunming 650093 Yunnan Peoples R China

The effect of relaxation treatment after finish rolling on microstructure and mechanical properties has been investigated for a vanadium and nitrogen microalloyed low carbon bainitic *** lath bainite microstructure can be obtained in the plate with *** results of quantitative statistics show that in the plate without relaxation,80% of the total bainite lath bundles are in the range 5-15μm in length and 3-13μm in width,while in the plate with relaxation 80% of the total bundles are in the range 3-9μm in length and 1-7μm in *** mechanical properties show that the plate with relaxation has higher impact energy,yield strength and hardness than the plate without relaxation,also the comprehensive performance after tempered at 650℃ is superior to the plate without relaxation.

关键词： low carbon bainitic steel microstructure refinement V-N Microalloying