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Coacervate Structures of CdI_2.Thin Film Grown during Phase Transformation

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Journal of Materials Science & Technology 1997年第4期13卷 296-298页

作者： Xiaoyan YE and Lili CAO(Dept. of Chemistry, tsinghua university, beijing 100084, China)Jizhong ZHANG and Hengde LI(Dept. of Materials Scieuce & {2., tsinghua university, beijing 100084, China) Dept. of Chemistry Tsinghua University Beijing 100084 China Dept. of Materials Science and engineering Tsinghua University Beijing 100084 China

The microstructure of CdI2.thin film grown during vapor-phase deposition was investigated by scanning electron microscopy (SEM). The thin film deposited on Si crystal consists of numerous sunflower-like aggregates. These aggregates display well self-assembly characteristics. The size of Sunflower-like aggregates is between 12.and 44 μm. Each sunflower-like aggregate is surrounded with many adjacent wings-'petals'. The structure of central region of the 'sunflower' is obviously difFerent from that of the 'petal'. Electron spectroscopy for chemical analysis (ESCA) was employed in determining the chemical valence of the thin film. Self-organization efFect is used to explain the coring growth process of CdI2.thin film

关键词： Thin Coacervate Structures of CdI2.Thin Film Grown during Phase Transformation

INTERFACIAL REACTIONS OF METAL FILMS WITH AlN SUBSTRATE

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中国有色金属学会会刊：英文版 1996年第2期6卷 81-85页

作者： He Xiangjun Tao Kun Fan Yudian (Department of Materials Science and engineering, tsinghua university,{2.) Department of Materials Science and engineering Tsinghua University Beijing 100084 China

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关键词： thin films interfacial reactions AlN substrate

A SMOOTH C^1 INTERPOLATION FOR TWO-DIMENSIONAL CONTACT PROBLEMS USING PARAMETRIC CURVE TECHNIQUE

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Acta Mechanica Solida Sinica 2003年第3期16卷 205-209页

作者： Kou Zhejun Cheng Jiangang Yao Zhenhan Wang Fujun (Department of engineering mechanics,{2. university,beijing 100084,China) Department of engineering mechanics Tsinghua University Beijing 100084 China

A smooth C^1 interpolation for two-dimensional contact problems using parametric curve technique was developed and *** parametric curve can ensure C^1 continuity of the contact surfaces and provide a unique surface normal *** numerical examples were used to illustrate the advantages of the newly developed representation of contact surface. The results reveal a significant improvement in the prediction of contact stresses and contact *** predicted contact stresses are less sensitive to the mismatch in meshes of the different contacting bodies.

关键词： smooth interpolation parametric curve contact finite element

EXPERIMENTAL PLASTIC DEFORMATION ANALYSIS BY MEANS OF THERMOPLASTIC EFFECT

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Acta Mechanica Solida Sinica 1997年第3期10卷 276-282页

作者： Sun Xuewei Tu J Zhu D. Z., Department of engineering mechanics,{2., beijing 100084, China TSING HUA UNIV DEPT ENGN MECHBEIJING 100084PEOPLES R CHINA

This paper proposes a new experimental method of quantitative plastic deformation analysis by means of the thermoplastic effect. The incremental plastic strain distribution for a single shear specimen was obtained by ... 详细信息

关键词： plastic deformation thermoplastic effect

Analysis on ignition and extinction of n-heptane in homogeneous systems

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Science China(Technological Sciences) 2005年第5期48卷 556-569页

作者： LIU Yongfeng1 & PEI Pucheng2.1. Mechanical and Electrical engineering Department, {2. Institute of Civil engineering and Architec-ture, {2. 100044, China 2. State Key Laboratory of Automotive Safety and Energy, tsinghua university, beijing 100084, China 1. Mechanical and Electrical engineering Department Beijing Institute of Civil Engineering and Architecture 100044 Beijing China 2. State Key Laboratory of Automotive Safety and Energy Tsinghua University 100084 Beijing China

To calculate ignition delay times, the governing equations about species and temperature, which are in a closed volume based on the theory of thermal explosion and in a continuously stirred flow reactor, are deducted. The method referred to steady state assumptions is based on the observation that due to very fast chemical processes in combustion problems many chemical species and reactions are in a quasi-steady state or partial equilibrium. When a species is assumed to be in the steady state, the corresponding differential equation can be replaced by an algebraic relation, which reduces the computational costs. The steady state solution of the reactor equations describes the three ignition temperature regimes and get “S-shaped curve”. The reduced simplified 4-step mechanism for n-heptane from 1011 elementary reactions leads with the steady state assumptions to linear differential equations, which is solved. The simulation results of the 4-step reduced mechanism for n-heptane are fitted well with the experiment data. At last, two important parameters are discussed thoroughly and the temperature perturbation is given. It reduces the computational efforts considerably without losing too much accuracy and further supplies numerical methods for turbulent combustion in the diesel engine.

关键词： ignition delay times, thermal runaway, steady state assumptions, continuously stirred flow reactor.

Mapping and overlapping based carrier frequency searching technique for rapid GNSS long PN-code acquisition

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Science China(Information Sciences) 2010年第12期53卷 2642-2652页

作者： LI Hong ,LU MingQuan & feng ZhenMing Department of Electronic engineering,{2. university,beijing 100084,China 1. Department of Electronic engineering Tsinghua University Beijing 100084 China

In global navigation satellite systems(GNSS),because of the long period and high chip rate of long pseudo-noise(PN) code,the rapid acquisition is hard to *** speed up search process,in the paper,a mapping and overlapping based carrier frequency searching technique is *** mapping incoming signals of the same interval to different carrier frequency cells and overlapping together the mapped incoming signals that correspond to the same code phase,the technique reduces the number of the cells to be *** effect of the technique on detection and mean acquisition time performance is *** is shown that the technique reduces the cells to be searched and shortens mean acquisition time at the expense of degrading detection *** technique is fit to the previously published acquisition methods and is capable of improving their mean acquisition time *** and simulation results validate the analysis.

关键词： carrier frequency cells mapping overlapping acquisition performance

Expression of lignin peroxidase H2.from Phanerochaete chrysosporium by multi-copy recombinant Pichia strain

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Journal of Environmental Sciences 2009年第2期21卷 218-222页

作者： WANG Wei,WEN Xianghua Department of Environmental Science and engineering,tsinghua {2.,beijing 100084,China. Department of Environmental Science and engineering Tsinghua University Beijing 100084 China

The lipH2.gene, encoding the expression of lignin peroxidase, was cloned from Phanerochaete chrysosporium BKM-F-1767 and expressed in Pichia pastoris X-33, a yeast. The cDNA of LiPH2.was generated from total RNA extracted from P chrysosporium by PCR with primers that do not contain a P. chrysosporium lignin peroxidase secretion signal. The gene was then successfully inserted into the expression vector pPICZα, and resulted in the recombinant vector pPICZα-lipH2. The transformation was conducted in two ways. One was using the wild Pichia pastoris as the recipients, which results in the recombinant P. pastoris with single or low lipH2.gene copy. The second was using P. pastoris and single or low lipH2.gene copy as the recipients, which results in the recombinant P. pastoris with multi-copies of lipH2.genes. This study firstly expressed the gene lipH2.in P. pastoris and achieved the successful expression of the lipH2.depending upon the generation of a recombinant strain that contained multiple copies. The lignin peroxidase activity reached a maximum of 15 U/L after 12.h induction.

关键词： heterologous expression lignin peroxidase Pichia pastoris

GENERATION AND APPLICATION OF VARIATIONAL GEOMETRIC CONSTRAINTS NETWORK BASED ON ISO'S FEATURE

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Chinese Journal of Mechanical engineering 2002年第4期15卷 319-323页

作者： Hu JieState CIMS engineering Research Center, tsinghua university,{2., ChinaWu Zhaotong Zhejiang university State CIMS engineering Research Center Tsinghua University Beijing 100084 China

The concept of variantional geometric constraints network is presented. Basedon ISO's feature, three kinds of variational geometric constraints are defined. The concepts ofmate tree (MT) and loop circuit (LC) are presented. The generation method of well-constrainedvariational geometric constraints network (VGCN) is studied. The network can be applied ingeneration of well-constrained tolerance types and tolerance chains. A simple example is analyzed toshow the scheme to be effective.

关键词： ISO's feature variational geometric constraint tolerance

An atlas-based fuzzy connectedness method for automatic tissue classification in brain MRI

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Progress in Natural Science:Materials International 2006年第10期16卷 1106-1110页

作者： ZHOU Yongxin and BAI Jing (Department of Biomedical engineering, tsinghua university,{2., China) [a]Department of Biomedical engineering Tsinghua University Beijing China

A framework incorporating a subject-registered atlas into the fuzzy connectedness (FC) method is proposed for the automatic tissue classification of 3D images of brain MRI. The pre-labeled atlas is first registered onto the subject to provide an initial approximate segmentation. The initial segmentation is used to estimate the intensity histograms of gray matter and white matter. Based on the estimated intensity histograms, multiple seed voxels are assigned to each tissue automatically. The normalized intensity histograms are utilized in the FC method as the intensity probability density function (PDF) directly. Relative fuzzy connectedness technique is adopted in the final classification of gray matter and white matter. Experimental results based on the 2. data sets from IBSR are included, as well as comparisons of the performance of our method with that of other published methods. This method is fully automatic and operator-independent. Therefore, it is expected to find wide applications, such as 3D visualization, radiation therapy planning, and medical database construction.

关键词： fuzzy connectedness atlas-based segmentation brain tissue classification MR1.