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Science in China(Series F) 2009年第10期52卷 1848-1862页

作者： zhang heming CIMS-ERC Department of Automation TNList Tsinghua University Beijing 100084 China

This paper presents an integrated approach to multidisciplinary collaborative simulation for complex engineering systems. The formulized paradigm of multidisciplinary collaborative simulation for com- plex engineering systems is principally analyzed. An IEEE HLA and web services based framework is proposed to provide a heterogeneous, distributed and collaborative running environment where multidisciplinary modeling, running management and post-processing of collaborative simulation are undertaken. The mechanism of multidisciplinary collaborative modeling, disciplinary model transformation, and time-synchronized simulation advancement are studied in detail. A prototype with the functions of multidisciplinary modeling, running management and post-processing for collaborative simulations is developed, and a typical complex engineering system is chosen as a case study to demonstrate the effectiveness of this new approach towards collaborative simulation.

关键词： multidisciplinary modeling distributed collaborative simulation HLA web services complex engineering system

APPLICATION OF STEP IN CAD/CAPP INTEGRATION

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Chinese Journal of Mechanical Engineering 1998年第2期11卷 10-16页

作者： Wu, Ruirong zhang, heming Qinghua Univ China

A brief discussion of the content and methodology of STEP is given, and STEP based strategies for CAD/CAPP information integration is pointed out. A STEP based feature technology in which a three layer feature definition is included is discussed, the content of feature information is analyzed and a stratified CAD feature library is shown. On these bases, a commonly shared part information model is proposed. The architecture of the integrated CAD/CAPP system is presented.

关键词： STEP CAD/CAPP Integration Feature

Combinative Algorithms for the Multidisciplinary Collaborative Simulation of Complex Mechatronic Products Based on Major Step and Convergent Integration Step

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Chinese Journal of Mechanical Engineering 2011年第3期24卷 355-363页

作者： LIANG Silue zhang heming WANG Hongwei National CIMSEngineeringResearch Center Tsinghua University Beijing 100084 China Computer and Information Management Center Tsinghua University Beijing 100084 China Engineering Design Centre University of Cambridge Cambridge CB2 1PZ UK

Multidisciplinary collaborative simulation （MCS） is an important area of research in the domain of multidisciplinary design optimization （MDO）.Although previous research for MCS has to some extent addressed some issues like using of multiple tools,integration stability,control of step size,data synchronization,etc,further work is still necessary to study how to achieve improved precision.A theoretical model is formulated to describe and analyze the integration process of MCS.A basic algorithm with equal major steps is proposed based on the model,along with two methods of implementation for the model,namely the serial method and the parallel method.A further algorithm based on convergent integration step is proposed,which has a more flexible strategy for run-time *** influence of interpolation techniques on simulation performance is studied as *** of the performance of various algorithms with different interpolation techniques are performed for both a simple numerical example and a complex mechatronic *** novel algorithm based on convergent integration step,when used with a high-order interpolation technique,has better performance in terms of precision and *** innovation of this paper is mainly on the validation of high precision of the proposed convergent integration step algorithm.

关键词： mechatronic product multidisciplinary collaborative simulation multi-rate integration convergent integration step

BOM-BASED DESIGN KNOWLEDGE REPRESENTATION AND REASONING FOR COLLABORATIVE PRODUCT DEVELOPMENT

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Journal of Systems Science and Systems Engineering 2016年第2期25卷 159-176页

作者： Gongzhuang Peng Huachao Mao Hongwei Wang heming zhang National CIMSEngineeringResearch Center Tsinghua University Beijing 100084 China School of Engineering University of Portsmouth Anglesea Read Portsmouth PO1 3D J UK

Modem product development becomes increasingly collaborative and integrated, which raises the need for effectively and efficiently sharing and re-using design knowledge in a distributed and collaborative environment. To address this need, a framework is developed in this research to support design knowledge representation, retrieval, reasoning and fusion, which takes account of structural, functional and behavioral data, various design attributes and knowledge reasoning cases. Specifically, a multi-level knowledge representation based on the Base Object Model （BOM） is proposed to enable knowledge sharing using Web services technologies. On this basis, a multi-level knowledge reuse method is developed to support the retrieval, matching and assembly of knowledge records. Due to the tree structure of BOM, both depth-first and breadth-first searching strategies are employed in the retrieval algorithm while a novel measure is proposed to evaluate similarity. Moreover, a method based on the D-S evidence theory is developed to enable knowledge fusion and thus support effective decision-making. The framework has been implemented and integrated into an HLA-based simulation platform on which the development of a missile simulation example is conducted. It is demonstrated in the case study that the proposed framework and methods are useful and effective for design knowledge representation and reuse.

关键词： Complex product development multi-level knowledge reuse knowledge fusion Base Object Model D-S evidence theory

Thermodynamic equilibrium diagram of the chlorine-titanium system

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Rare Metals 2005年第4期24卷 313-316页

作者： DU Ailing GUO Xiaofei zhang heming LIU Jiang School of Chemistry and Chemical Engineering Shandong University Jinan 250061 China

The chemical and electrochemical equilibria of the chlorine-titanium system in the presence of gaseous phase were investigated. Many species, which consisted of chlorine and titanium, were considered. Various thermodynamic equilibria were calculated in the different pressures at different temperatures. The calculated results were shown as log p-1/Tand E-T diagrams. These diagrams may be used as important tools for corrosion study and titanium production. The diagrams are also used to thermodynamically determine the existence areas of various species and so on.

关键词： physical chemistry thermodynamic equilibrium equilibrium diagram chlorine-titanium system

Hole mobility enhancement in uniaxial stressed Ge dependence on stress and transport direction

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Science China(Physics,Mechanics & Astronomy) 2014年第10期57卷 1860-1865页

作者： MA JianLi FU ZhiFen LIU Peng zhang heming School of Physics and Information Technology Shaanxi Normal University Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices Xidian University

Utilizing a six-band k.p valence band calculations that considered a strained perturbation Hamiltonian, uniaxial stress-induced valence band structure parameters for Ge such as band edge energy shift, split, and effective mass were quantitatively evaluated. Based on these valence band parameters, the dependence of hole mobility on uniaxial stress(direction, type, and magnitude) and hole transport direction was theoretical studied. The results show that the hole mobility had a strong dependence on the transport direction and uniaxial stress. The hole mobility enhancement can be found for all transport directions and uniaxial stess configurations, and the hole transport along the [110] direction under the uniaxial [110] compressive stress had the highest mobility compared to other transport directions and stress configurations.

关键词： Ge uniaxial stress valence band structure hole mobility

Calculation of band structure in (101)-biaxially strained Si

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Science China(Physics,Mechanics & Astronomy) 2009年第4期52卷 546-550页

作者： SONG JianJun zhang heming HU HuiYong FU Qiang Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices School of MicroelectronicsXidian UniversityXi’an 710071China

The structure model used for calculation was defined according to Vegard’s rule and Hooke’s law. Calculations were performed on the electronic structures of (101)-biaxially strained Si on relaxed Si1?X Ge X alloy with Ge fraction ranging from X = 0 to 0.4 in steps of 0.1 by CASTEP approach. It was found that [±100] and [00±1] valleys (δ4) splitting from the [0±10] valley (Δ2) constitute the conduction band (CB) edge, that valence band (VB) edge degeneracy is partially lifted and that the electron mass is unaltered under strain while the hole mass decreases in the [100] and [010] directions. In addition, the fitted dependences of CB splitting energy, VB splitting energy and indirect bandgap on X are all linear.

关键词： strained Si band structure effective mass

Hole scattering mechanism of strained Si/(111)Si_(1-x)Ge_x

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Science China(Physics,Mechanics & Astronomy) 2011年第10期54卷 1801-1804页

作者： WANG Cheng zhang heming SONG JianJun HU HuiYong Key Lab of Wide Band-Gap Semiconductor Materials and Devices School of Microelectronics Xidian University Xi'an 710071 China

Based on Fermi’s golden rule and the theory of Boltzmann collision term approximation, the hole scattering mechanism ofstrained Si/(111)Si1 xGexwas established, including ionized impurity, acoustic phonon, non-polar optical phonon and totalscattering rate models. It was found that the total scattering rate of the hole in strained Si/(111)Si1 xGexdecreased obviouslywith the increasing stress when energy was 0.04 eV. In comparison with one of the unstrained Si, the total hole scattering rateof strained Si/(111)Si1 xGexdecreased about 38% at most. The decreasing hole scattering rate enhanced the hole mobility instrained Si materials. The result could provide valuable references to the research on hole mobility of strained Si materials andthe design of PMOS devices.

关键词： strained Si scattering rates mobility

Hole mobility of strained Si/(001)Si_(1-x)Ge_x

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Science China(Physics,Mechanics & Astronomy) 2012年第1期55卷 48-54页

作者： WANG XiaoYan zhang heming MA JianLi WANG GuanYu QU JiangTao Key Laboratory for Wide Band-Gap Semiconductor Materials and Devices School ofMicroelectronics Xidian University Xi＇an 710071 China Department of Electron and Electricity Engineering Baoji University of Arts and Sciences Baoji 721007 China

The hole mobility of strained silicon along the orientation on (001) Si1?xGex is obtained by solving collision term in the Boltzmann transport equation. The analytical model is proposed that considers the effect of strain-induced splitting at valence band valleys in silicon, doping dependence and three scattering mechanisms, i.e., ionized impurity scattering, acoustic phonon scattering and non-polar optical phonon scattering. The hole occupancy at top band indicates a non-monotonic variation under biaxial tensile strain at low temperature (77 K). What's more, a non-monotonic variation of hole mobility at room temperature (300 K) is presented. Compared with the room temperature hole mobility, the low temperature hole mobility is affected greatly by ionized impurity scattering at lower impurity concentration. At the same time, the room temperature hole mobility is lower than that of electron with the same germanium content and doping concentration. If the parameters are correctly chosen, the model can also be used to calculate the hole mobility of other crystal faces with arbitrary orientation. So, it lays a useful foundation for strained silicon devices and circuits.

关键词： subband hole occupancy scattering model germanium content hole mobility

Hole effective mass in strained Si (111)

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Science China(Physics,Mechanics & Astronomy) 2011年第3期54卷 450-452页

作者： HU HuiYon zhang heming SONG JianJun XUAN RongXi DAI XianYing Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices School of Microelectronics Xidian University Xi’an 710071 China

The directional, averaged, and density-of-states effective masses of holes have been calculated for strained Si/(111)Si1-xGex. The results for the directional effective mass show that the effect of strain makes the constant energy surface of "heavy" holes more obvious warping than that in relaxed Si. The [111] and [110] directional effective masses of "heavy" holes decrease significantly under strain. It is found that the averaged effective mass of "heavy" holes decreases with increasing Ge fraction, while that of "light" holes increases. The traditional concepts of heavy and light holes become insignificant when Ge fraction is close to 0.4. The strain effect monotonically reduces the density-of-states effective mass at 218, 300 and 393 K, respectively.

关键词： strained Si hole effective mass