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The General Machining Process Simulator GMPS

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Journal of Systems Engineering and Electronics 1994年第3期5卷 73-79页

作者： Xiao Tianyuan, Yang Gang & Li Xin (department of Automation, tsinghua university, {2., china, 100084) department of Automation Tsinghua University Beijing China 100084

Automated manufacturing system is characterized by flexibility. It aims at producing a variety of products with virtually no time loses to change over from one part to the next. In this paper, the Machining Process Simulator GMPS is introduced, which can be used as a supported environment for machining process. It can be executed off-line or on-line in manufacturing systems in order to predict the collisions of tool with machined workpieces, fixtures or pallets. First, the functional model of GMPS is described, then adopted critical techniques in the simulator are introduced. Finally, an application of GMPS in CIMS ERC of china is presented.

关键词： Machining process simulator Modeling Front End DNC NC code translator 3D animation detecting collision.

Generalized gradient projection neural networks for nonsmooth optimization problems

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Science china(Information Sciences) 2010年第5期53卷 990-1005页

作者： LI GuoCheng 1 , SONG ShiJi 2.? & WU Cheng 2.1 department of Mathematics, beijing Information Science and Technology {2., beijing 100192. china 2.department of Automation, tsinghua university, beijing 100084, china 1. department of Mathematics Beijing Information Science and Technology University Beijing 100192 China2. Department of Automation Tsinghua University Beijing 100084 China

Generalized gradient projection neural network models are proposed to solve nonsmooth convex and nonconvex nonlinear programming problems over a closed convex subset of R n . By using Clarke’s generalized gradient, the neural network modeled by a differential inclusion is developed, and its dynamical behavior and optimization capabilities both for convex and nonconvex problems are rigorously analyzed in the framework of nonsmooth analysis and the differential inclusion theory. First for nonconvex optimization problems, the quasi convergence results similar to those achieved by previous work are proved. For convex optimization problems, the global convergence results are proved, i.e. any trajectory of the neural network converges to an asymptotically stable equilibrium point, which is an optimal solution of the primal problem whenever it exists. This result remains valid even if the initial condition is chosen outside the feasible set. In addition, an asymptotic control result involving a Tykhonov like regularization shows that any trajectory of the revised neural network can be forced to converge toward a particular optimal solution of the primal problem. Finally, two simulation optimization algorithms for solving the optimization and control problems are designed respectively, and three typical simulation experiments are illustrated to present the accuracy and efficiency of theoretical convergence results of this paper.

关键词： nonsmooth optimization problem generalized gradient projection networks differential inclu sions convergence

|m| Partial wave treatment for two-dimensional Coulomb-scattering and Regge pole

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Science china(Physics,Mechanics & Astronomy) 2004年第6期47卷 676-684页

作者： WANG Jing & ZENG Jinyan department of Physics,tsinghua {2.,beijing 100084,china School of Physics,Peking {2.,beijing 100871,china department of Physics Tsinghua University Beijing 100084 China School of Physics Peking University Beijing 100871 China

The symmetry and |m| partial-wave analysis for two-dimensional (2.) Coulomb-scattering is investigated. As a function of energyE, the |m| partial-wave scattering amplitudef |m|(θ) is analytically continuated to the, negativeE (complexk) plane, and it is found that the bound state energy eigenvalues (E<0) are just located at the poles off |m|(θ) on the positive imaginaryk axis as is expected. In addition, as a function of |m|,f |m|(θ) is analytically continuated to the complex |m| plane, the bound state energy eigenvalues are just located at the poles off |m|(θ) on the positive real |m| axis.

关键词： two-dimensional Coulomb scattering, |m| partial-wave, Regge pole.

CONSERVATION OF THREE-POINT COMPACT SCHEMES ON SINGLE AND MULTIBLOCK PATCHED GRIDS FOR HYPERBOLIC PROBLEMS

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Journal of Computational Mathematics 2003年第3期21卷 383-400页

作者： Zi-niu Wu (department of Engineering Mechanics, tsinghua university,{2., china) department of Engineering Mechanics Tsinghua University 北京 100084

For nonlinear hyperbolic problems, conservation of the numerical scheme is important for convergence to the correct weak solutions. In this paper the conservation of the well-known compact scheme up to fourth order of accuracy on a single and uniform grid is studied, and a conservative interface treatment is derived for compact schemes on patched grids. For a pure initial value problem, the compact scheme is shown to be equivalent to a scheme in the usual conservative form. For the case of a mixed initial boundary value problem, the compact scheme is conservative only if the rounding errors are small enough. For a patched grid interface, a conservative interface condition useful for mesh refinement and for parallel computation is derived and its order of local accuracy is analyzed.

关键词： Conservation Compact scheme Uniform grid Multiblock patched grid.

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

Effect of Fluid Electrical Property Changes on Surface Transverse Wave Sensors

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稀有金属材料与工程 2006年第S3期 514-518页

作者： Chao Zhang~1 Wenyan Wang~2.Yonggui Dong~2.Yan Liu~1 Guanping Feng~1 (1.Research Institute of tsinghua university in Shenzhen,Shenzhen 518057,china) (2.{2. of precision instruments and mechanology,tsinghua university,beijing 100084,china)

A fluid sensor based on the surface transverse wave (STW) delay line on ST-cut quartz has been developed and tested in a large number of fluids with different viscosity and permittivity *** of fluid mechanical and electrical properties on the sensor's response has been determined and the sensor's performance has been compared with a bulk acoustic wave (BAW) viscosity *** result shows that the viscosity sensitivity of the developed STW sensor represented by the signal to noise ratio is lower than that of a 5 MHz BAW *** of the sensor in detecting the quality of industrial fluids are discussed.

关键词： surface transverse wave surface acoustic wave fluid sensor electrical property

A SINGLE-PERIOD INVENTORY SYSTEM WITH A GENERAL S-SHAPED UTILITY AND EXPONENTIAL DEMAND

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Journal of Systems Science and Systems Engineering 2010年第2期19卷 227-236页

作者： Wei GENG1 Xiaobo ZHAO2.Deng GAO3 department of Industrial Engineering,tsinghua {2.,beijing 100084,china department of Industrial Engineering Tsinghua University Beijing China

We discuss a single-period inventory system with a general S-shaped utility function and exponential demand. It is shown that there exists a state-dependent order-up-to policy to be optimal. Behaviors of optimal polic... 详细信息

关键词： Inventory S-shaped utility function order-up-to policy

USING LOGIC COMPONENTS FOR CONCEPTUAL DIE DESIGN

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Chinese Journal of Mechanical Engineering 2001年第2期14卷 151-155页

作者： Tang Dunbing Zheng Li Li Zhizhong department of precision {2. and mechanology,Qinghua university 清华大学精密仪器与机械学系北京

Logic components are used to support the conceptual design Taking the stamping die structure as the research object,several logic components are defined for the conceptual die construction design A new method logic assembly modeling is presented to satisfy the characteristic of the top down die design process Representing shapes and spatial relations in logic can provide a natural,intuitive method of developing complete computer systems for reasoning about die construction design at the conceptual stage This method can reflect the designer's thought clearly and provide the designer with a test bed for generating alternatives and performing reasoning work at the conceptual die design stage

关键词： CAD Conceptual design Die Logic component Logic assembly model

A　Optical　Scheme　for　Parallelly　Realizing　the　Morphological　Erosion　of　1－D　Gray　Images

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Chinese Journal of Lasers 1996年第3期B5卷 282-288页

作者： HUANG Guoliang JIN Guofan WU Minxian YAN Yingbai(Dept. of precision instruments,{2., beijing 100084) tsinghua Univ Beijing China

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关键词： mathematical morphology digital umbra sheding shadowing algorithm