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Analysis of residual stress distribution along interface asperity of thermal barrier coating system on macro curved surface

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Progress in Natural Science:Materials International 2011年第3期21卷 262-267页

作者： Ming SONG,Yue MA,Sheng-kai GONG Key Laboratory of Aerospace Materials and Performance(Ministry of Education), School of Materials Science and Engineering,Beihang university,beijing 100191,{2. Key Laboratory of Aerospace Materials and Performance (Ministry of Education) School of Materials Science and Engineering Beihang University Beijing 100191 China

Based on the study of the radial residual stress distribution on the macro curved interfaces of thermal barrier coating system(TBCs) for the hollow curved substrate structures,the hollow four-concentric-circle model was *** the concentric-circle model with a fine scaled sinusoidal interface was proposed to describe the stresses distribution on the rough interface of TBCs with macro curved *** influences of the geometric and thermophysical parameters were discussed by the developed *** results showed that the radial stress on the rough interface can be separated into two sections:the overall level stress from macro surface curvature and the local stress from local asperity of the *** overall level stress was determined by the thicknesses and the thermophysical parameters of each *** has been found that the ratio of local stress and overall level stress was influenced by the interface asperity,the ratio of elastic modulus and the ratio of thermal expansion coefficients of the layers beside the rough ***,the convex macro curvature of the substrate can induce tensile stress onto the *** at the sharp corners of the substrate,the small curvature radius can cause high stress which should be taken more care about the occurrence of spalling cracking at interface

关键词： barrier coating system(TBC) residual stress interface asperity thermal grown oxide(TGO) concentric-circle model

Electronic packaging materials prepared by powder injecting molding and pressure infiltration process

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Rare Metals 2007年第6期26卷 625-629页

作者： YIN Fazhang GUO Hong JIA Chengchang XU Jun ZHANG Ximin ZHU Xuexin National Engineering and Technology Research Center for Nonferrous Metals Composites Beijing General Research Institute for Nonferrous Metals Beijing 100088 China Materials Science and Engineering School University of Science and Technology Beijing Beijing 100083 China

AlSiCp （65 vol.% SiC） electronic packaging materials were manufactured by powder injection molding （PIM） and pressure infiltration process in order to obtain near net-shaped parts. SiCp preformed compacts obtained by pre-sintering process at 1150 K have high strength and good appearance, and the ratio of open porosity to total porosity is nearly 98%. The relative density of composites is bigger than 99%. The thermal conductivity of A1SiCp composites fabricated by this method is 198 W·m^-1·K^-1, and the coefficient of thermal expansion （CTE） is 8.0 × 10^-6/K （2.8 K）.

关键词： composites aluminum microstructure thermal conductivity

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Optimal Higher Order Learning Adaptive Control for a Class of SISO Nonlinear Systems

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Optimal Higher Order Learning Adaptive Control for a Class o...

Production of human lysozyme-transgenic cloned porcine embryos by somatic nuclear transfer

第二十四届中国控制会议

作者： Chi Ronghu~1, Hou Zhongsheng~2.(1. School of Traffic and Transportation of beijing Jiaotong university, beijing 100044 china) (2. School of Electronics and Information Engineering of beijing Jiaotong university, beijing 100044 china)

＜正＞ In this paper, an optimal higher order learning adaptive control is developed for a class of SISO nonlinear systems. The design is model-free, just based directly on pseudo-partial-derivatives derived on-line from the input and output information of the system. A novel weighted one-step-ahead control criterion function is proposed for the control law. The convergence analysis is given and it shows that the proposed control law can guarantee the convergence under the assumption that the desired output is a set point. Compared with the one order learning adaptive control method, simulation examples are provided for nonlinear systems to show the better performance of the higher order learning adaptive control.

关键词： optimal higher order learning adaptive control model-free convergence nonlinear system

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Progress in Natural Science:Materials International 2009年第6期19卷 699-704页

作者： Qiuyan Lia,b, Hengxi Wei a, Ying Guoa, Yan Lib, Rui Zhao b, Yufang Maa, Zhengquan Yu a, Bo Tang b, Lei Zhangb, Yunping Dai a,b, Ning Li a, a State Key Laboratory for Agrobiotechnology and Department of Animal Physiology, College of Biological Science, china Agricultural university, No. 2.Yuan-Ming-Yuan West Road,{2. 100094, china b Ji Pulin Biotech Ltd,{2. 100094, china [a]State Key Laboratory for Agrobiotechnology and Department of Animal Physiology College of Biological Science China Agricultural University No. 2 Yuan-Ming-Yuan West Road Beijing 100094 China [b]Ji Pulin Biotech Ltd Beijing 100094 China

Due to their physiology and organ size, pigs have significant potential as human disease models and as organ transplantation donors. Genetic modification of pigs could provide benefits for both agriculture and human medicine. In this study, five fetal pig fibroblast cell lines from two species (Wuzhishan and Landrace pigs) were transfected using double-marked human lysozyme (HLY) plasmids (pBC1-HLY-GFP-NEO) by a liposome-mediated method. The ratio of green fluorescent protein (GFP)-expressing cells was >95% in sw7, sw8, slw3 and slw6 cell lines, but only 49.3% in slw9 cells. Cells from the four highly transgenic lines were used as nuclear donors to construct embryos, which were then cultured after fusion and activation by electric stimulation. The rate of cleavage was 76.7%, 48 h after activation. After 7 days, 18.5% of cleaved eggs had developed to the blastocyst stage and 93.3% of blastocysts were GFP-positive. These results indicate that transgenic fetal pig flbroblast cell lines could be obtained by a liposome-mediated method, though the transfection efficiency varied between cell lines. Reconstructed embryos derived from transgenic cells could successfully develop into blastocysts, most of which were GFP-positive.

关键词： EGFP Porcine Nuclear transfer Fetal fibroblast Human lysozyme (HLY)

A fractal model for the effective thermal conductivity of nanoparticle suspensions

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Progress in Natural Science:Materials International 2004年第1期14卷 37-41页

作者： WANG Buxuan*, ZHOU Leping and PENG Xiaofeng(Thermal Engineering Department, Tsinghua university, beijing 100084,{2.) Tsing Hua Univ Thermal Engn Dept Beijing 100084 Peoples R China

Extending the effective medium approximation with the fractal theory for describing nanoparticle clusters and their radius distribution, a predictive model is proposed for the effective thermal conductivity of nanoparticle suspension, combined with the consideration of size effect and surface adsorption effect of nanoparticles. The predicted effective thermal conductivity of nanoparticle suspension is consistent with experimental data in the dilute limit.

关键词： fractal nanoparticle suspension surface adsorption size effect

Observation of nuclei reassembled from demembranatedXenopus sperm nuclei and analysis of their laminacomponents

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Cell Research 1994年第2期4卷 163-172页

作者： QU JIAN CHUANMAO ZHANG ZHONGHE ZHAI.(College of Life Sciences, beijing university, beijing100871, china) College of Life Sciences Beijing University Beijing China

A cell-free preparation obtained from extracts of activated Xenopus laevis eggs induced chromatin decondensation and nuclear formation from demembranated Xenopus sperm nuclei. Electron microscopy revealed that the reassembled nucleus had a double-layered nuclear membrane, nuclear pore complexes, and decondensed chromatin etc. Indirect immunofluorescence analysis demonstrated the presence of lamina in newly assembled nuclei. Western-blotting results showed that lamin LII was present in egg extracts and in lamina of the reassembled nuclei which were previously reported to contain only eggderived lamin LIII.

关键词： Nuclear assembly in vitro Xenopus laevis Lamina

Electromagnetic Compatibility of UHF-RFID to GSM

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Electromagnetic Compatibility of UHF-RFID to GSM

2.07 4th International Symposium on Electromagnetic Compatibility(EMC’2.07)

作者： Weijun Hong 1 Runtian Kan 2.Shufang Li 3 1 3 School of Telecommunication Engineering beijing university of Posts and Telecommunications beijing china 100876 2.National Radio Detection Center beijing china 100037

Global scale article track and information share can be achieved by combining RFID technology with global network,*** communication ***,the power transmitted by RFID reader or responded by RFID tags would probably cause interference to the communication link between the phone and base *** paper presents in what condition a RFID system would not cause performance degradation to GSM network while the RFID system is integrated into the GSM network.

关键词： RFID Radio Network Electromagnetic Compatibility GSM

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掺镧改性钛酸钡湿敏陶瓷元件

无机材料学报 2002年第6期17卷 1187-1193页

作者：刘静波王智民韩基新黑龙江大学化学化工学院

以La(OAc)3、Ba(OAc)2.Ti(OnBu)4为起始物,采用共溶-水凝胶法经陈化获得湿凝胶,干燥后制得干凝胶,研磨过筛和埋渗电极、加压成型为素坯,经不同温度和保温时间烧结,制得掺镧LaxBa1-xTiO3陶瓷传感元件系列(x=0.00,0.05,0.10,0.2.,0.30),... 详细信息

以La(OAc)3、Ba(OAc)2.Ti(OnBu)4为起始物,采用共溶-水凝胶法经陈化获得湿凝胶,干燥后制得干凝胶,研磨过筛和埋渗电极、加压成型为素坯,经不同温度和保温时间烧结,制得掺镧LaxBa1-xTiO3陶瓷传感元件系列(x=0.00,0.05,0.10,0.2.,0.30),测试其阻-湿特性,从中获得了具有良好特性参数的湿敏陶瓷及其主要工艺条件(x=0.10,1350℃/1h),阻-湿特性在工作湿度范围内(相对湿度RH=32.8％～93.6％)的平均灵敏度S=5×104kΩ/RH(％),线性相关因子r=0.998,响应时间τ=110s,湿滞低于4％,湿敏选择性良好:对H2.CH4,CH2.CH2.CH3CH=CH2.CO,C6H6和CH3CH2.H(g)七种气体具有抗干扰性能.应用SEM,AFM及XRF对陶瓷的显微结构和元素含量进行测定,确定了陶瓷的显微组织,晶粒尺寸,晶相结构,表面粗糙度和全元素分析.讨论了掺镧改性的可能机理:La3+不等价取代Ba2.,引起Ti4+捕获一个自由电子而变价为Ti3+,该电子在适宜的陶瓷显微结构下受水分子影响易于进入导带,使掺镧钛酸钡得以半导化,半径较小的La3+取代半径较大的Ba2.,则降低四方晶相的晶格畸变度δ,即晶轴比c/a变小,使四方晶格的不对称性及各向异性降低,从而减少陶瓷烧结后冷却过程中内应力引起的破裂.

关键词：掺镧改性钛酸钡湿敏陶瓷元件湿敏性能显微结构表征共溶-水凝胶法纳米多晶粉体

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The late Paleoproterozoic extension event:aulacogens and dyke Swarms in the North china craton

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Progress in Natural Science:Materials International 2006年第2期16卷 201-208页

作者： HOU Guiting, LI Jianghai, LIU Yulin and QIAN Xianglin (Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking university, beijing 100871,{2.) [a]Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space Sciences Peking University Beijing China

The extension structures and tectonic implication in the North china Craton ( NCC) are discussed in this paper based on the mafic dyke swarms and geochronology, combining with the geochronology of aulacogens. The late Paleoproterozoic time is the important turning point in the Precambrian evolution of the NCC. The extension system (e.g. aulacogens and dyke swarms) is widespread in the NCC, which marks the carbonization of the NCC with the rigid characteristic similar to the modern plate. The paleostress field modeling suggests that the dyke swarms and aulacogens are arogenic extension marking the start of the supercontinent, not synorogenic and post-orogenic extension. The mafic dyke swarms in the NCC mainly ranged from 1.83 to 1.77 Ga. The extension of the NCC is very limited brittle extension, the average extension ratio is only 0.35% given by mafic dyke swarms extension calculation, so most of extension in the NCC is contributed by the aulacogens. The mafic dyke swarms are related with the aulacogens in the origin.

关键词： North china craton late Paleoproterozoic aulacogens mafic dyke swarms extension.