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Gasdynamic characteristics of toroidal shock and detonation wave converging

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Science china(Physics,Mechanics & Astronomy) 2005年第6期48卷 739-749页

作者： TENG Honghui1,2.& JIANG Zonglin2.1. Key Laboratory of High Temperature Gas Dynamics, Institute of Mechanics, Chinese Academy of Sci- ences, beijing 100080, china 2. Graduate {2. of Chinese Academy of Sciences, beijing 100039, china Key Laboratory of High Temperature Gas Dynamics Institute of Mechanics Chinese Academy of Sciences Beijing China Graduate university of Chinese Academy of Sciences Beijing China

The modified CCW relation is applied to analyzing the shock, detonation wave converging and the role of chemical reactions in the process. Results indicate that the shock wave is strengthened faster than the detonation wave in the converging at the same initial Mach number. Euler equations implemented with a detailed chemical reaction model are solved to simulate toroidal shock and detonation wave converging. Gasdynamic characteristics of the converging are investigated, including wave interaction patterns, observable discrepancies and physical phenomena behind them. By comparing wave diffractions, converging processes and pressure evolutions in the focusing area, the different effects of chemical reactions on diffracting and converging processes are discussed and the analytic conclusion is demonstrated through the observation of numerical simulations.

关键词： converging, CCW relation, shock wave, detonation wave.

Internalization and distribution of three α1-adrenoceptor subtypes in HEK2.3A cells before and after agonist stimulation

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Acta Pharmacologica Sinica 2007年第3期28卷 359-366页

作者： Shu-yi WANG~2.Yao SONG~2.Ming XU~2.Qi-hua HE~3 Qi-de HAN~2.You-yi ZHANG~(2.4)2.Institute of Vascular Medicine,Peking university Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences,Ministry of Education,beijing {2.china 2.Center of Medical Analysis,Peking university,Health Science Center,beijing {2.china Institute of Vascular Medicine Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences Ministry of Education Beijing China Center of Medical Analysis Peking University Health Science Center Beijing China

Aim:To examine the subcellular distribution of the 3 α1-adrenoceptor（α1-AR）subtypes and their internalization and trafficking upon agonist stimulation in hu-man embryonic kidney 2.3A ***:Confocal real-time imaging,enzymelinked immunosorbent assay（ELISA）and whole cell[3H]-prazosin binding assaywere applied to detect the distribution and localization of the 3 α1B-AR ***:α1A-AR was found both on the cell surface and in the cytoplasm;α1B-AR,however,was predominantly detected on the cell surface,while α1D-AR wasdetected mainly in the intracellular *** stimulation withphenylephrine,localization changes were detected by confocal microscopy forα1A-and α1B-AR, but the localization of α1D-AR were *** promoted a more rapid internalization of α1B-AR than α1A-AR.α1D-ARinternalization was detected only by *** cell[3H]-prazosin bindingassay showed that α1A-AR functional receptors were detected both on the cellsurface and in the cytoplasm;α1B-AR,however,were detected predominantly onthe cell surface,while α1D-AR were detected mainly in intracellular *** stimulation promoted internalization of α1A-and α***:Phenylephrine stimulation induced changes in the localization of the3α1-AR.

关键词： adrenoceptor agonist stimulation confocal image enzyme-linked immunosorbent assay [~3H]-prazosin binding assay internalization subcellular distribution subtype

Seismic wave propagating in Kelvin-Voigt homogeneous visco-elastic media

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Science china Earth Sciences 2006年第2期49卷 147-153页

作者： YUAN Chunfang1, PENG Suping1, ZHANG Zhongjie2.& LIU Zhenkuan3 1. china university of Mining & Technology,{2. 2. Institute of Geophysics, Chinese Academy of Sciences, beijing 100101, china 3. Exploration and Development Research Institute of Daqing Oilfield, Daqing 163712. china china university of Mining & Technology Beijing China Institute of Geophysics Chinese Academy of Sciences Beijing China Exploration and Development Research Institute of Daqing Oilfield Daqing China

This paper studies, under a small disturbance, the responses of seismic transient wave in the visco-elastic media and the analytic solution of the corresponding third-order partial differential equation. A plane wave solution of Kelvin-Voigt homogeneous visco-elastic third-order partial differ-ential equation with a pulse source is obtained. By the principle of pulse stacking of particle vibration, the result is extended to the solution of Kelvin-Voigt homogeneous visco-elastic third-order partial differential equation with any source. The velocities of seismic wave propagating and the attenuation of seismic wave in Kelvin-Voigt homogeneous visco-elastic media are discussed. The velocities of seismic wave propagating and the coefficient of attenuation of seismic wave in Kelvin-Voigt homogeneous visco-elastic media are derived, expressed as functions of density of the media, elastic modulus and visco-elastic coefficient. These results can be applied in inversing lithology parameters in geophysical prospecting.

关键词： Kelvin-Voigt visco-elastic velocity attenuation seismic wave.

MD simulation of the effect of contact area and tip radius on nanoindentation

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Science china(Physics,Mechanics & Astronomy) 2004年第1期47卷 101-112页

作者： CHEN Shangda1,2.& KE Fujiu1,2.1. Department of Applied Physics, beijing university of Aeronautics and Astronautics,{2. 2. State Key Laboratory of Non-linear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences, beijing 100080, china Correspondence should be addressed to Chen Shangda (email: chensd@***) Received August 2., 2.03 Department of Applied Physics Beijing University of Aeronautics and Astronautics Beijing China State Key Laboratory of Non-linear Mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences Beijing China

Molecular dynamics simulations of nanoindentation are performed on monocrystal copper. A new contact atoms method is presented for calculating the contact area. Compared with conventional methods, this method can provide the contact area more accurately not only for sink-in but also for pile-up situation. The effect of tip radius on indentation is investigated too. The results indicate that the measured hardness of the material will become higher as the tip radius increases.

关键词： nanoindentation, molecular dynamics, contact area, zero point of penetration depth, nano- hardness.

An equality on Hochschild homology groups

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Chinese Science Bulletin 1997年第8期42卷 624-627页

作者： ZHANG Pu and LIU Shaoxue1. Department of Mathematics, university of Science and Technology of china, Hefei 2.002., china 2. Department of Mathematics, beijing Normal university, beijing 100875, china Department of Mathematics University of Science and Technology of China Hefei China Department of Mathematics Beijing Normal University Beijing China

LET A be finite-dimensional algebra over field k,and Ae the enveloping algebra of A,i.e.Ae=A kAop,where Aop is the opposite algebra of *** A-bimodule has a natural left Ae-module structure as follows:

关键词： finite-dimensional algebra Hochschild homology groups dimensions.

Algorithm of simulation time synchronization over large-scale nodes

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Science in china(Series F) 2008年第9期51卷 1239-1255页

作者： ZHAO QinPing1,2.ZHOU Zhong1,2.& Lü Fang1,2.1 State Key Laboratory of Virtual Reality Technology and Systems,Beihang university,beijing {2.china 2.School of Computer Science and Engineering,Beihang university,beijing {2.china State Key Laboratory of Virtual Reality Technology and Systems Beihang University Beijing China School of Computer Science and Engineering Beihang University Beijing China

In distributed simulation, there is no uniform physical clock. And delay cannot be estimated because of jitter. So simulation time synchronization is essential for the event consistency among nodes. This paper investigates time synchronization algorithms over large-scale distributed nodes, analyzes LBTS （lower bound time stamp） computation model described in IEEE HLA standard, and then presents a grouped LBTS model. In fact, there is a default premise for existing algorithms that controi packets must be delivered via reliable transportation. Although, a theorem of time synchronization message＇s reliability is proposed, which proves that only those control messages that constrain time advance need reliability. It breaks out the default premise for reliability. Then multicast is introduced into the transmis- sion of control messages, and algorithm MCTS （multi-node coordination time synchronization） is proposed based on multicast. MCTS not only promotes the time advance efficiency, but also reduces the occupied network bandwidth. Experiment results demonstrate that the algorithm is better than others in both time advance speed and occupied network bandwidth. Its time advance speed is about 50 times per second when there are 1000 nodes, approximately equal to that of similar systems when there are 100 nodes.

关键词： distributed simulation time synchronization multi-node coordination LBTS multicast

A general finite element model for numerical simulation of structure dynamics

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Science china(Physics,Mechanics & Astronomy) 2006年第4期49卷 440-450页

作者： WANG Fujun1, LI Yaojun1, Han K.2.& Feng Y.T.2.1. College of Water Conservancy and Civil Engineering, china Agricultural university,{2. 2. Civil & Computational Engineering Centre, university of Wales Swansea, Swansea SA2.8PP, U.K. College of Water Conservancy and Civil Engineering China Agricultural University Beijing China Civil & Computational Engineering Centre University of Wales Swansea Swansea UK

A finite element model used to simulate the dynamics with continuum and discontinuum is presented. This new approach is conducted by constructing the general contact model. The conventional discrete element is treated as a standard finite element with one node in this new method. The one-node element has the same features as other finite elements, such as element stress and strain. Thus, a general finite element model that is consistent with the existed finite element model is set up. This new model is simple in mathematical concept and is straightforward to be combined into the existing standard finite element code. Numerical example demonstrates that this new approach is more effective to perform the dynamic process analysis in which the interactions among a large number of discrete bodies and continuum objects are included.

关键词： finite element method, discrete element method, structure dynamics, numerical simulation.

The Influence of the Inclusion on the Fatigue Strength of Ceramic Bush

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厦门大学学报（自然科学版） 2002年第S1期41卷 56-57页

作者： YANG He-lai 1, DAI Yan-liang 2.(1. beijing university of Aeronautics and Astronautics,{2. 2. American Standard Pottery (Tianjin) Co., Tianjin 300181, china)

In traditional plain bearing, bushes are made of metal. In order to improve the properties of the bush, it is necessary to conduct an experiment in which the purpose is to replace metal with ceramic. Because of its high hardness, long fatigue wear life, excellent corrosion resistance, good self-lubricating and low density, ceramic bush is suitable for plain bearing. In this paper the influence of the inclusion on the fatigue wear strength of the bush are analysed under the action of a external load with the finite element method. All these work may provide proofs for analysing the wearing mechanism and for controlling the effect of the inclusion. When the normal outer load is 6 N/mm, namely P=6 N/mm. The compressive main stress will be formed inside the basic part of the bush, which gathers in the center touching area between the journal and the the bush around the inclusion, most of the units have their own maximum alternate stress σ max, which is smaller than the fatigue limit of the material of bushes σ 0 (σ 0=60 MPa). If there is P=30 N/mm, some units will have σ max approaching the fatigue limit, stress concentration will occur around the inclusion, so will the local plastic deformation. Some special units exceed the fatigue limit of the material. When P=2.5 N/mm,most of the units will have the σ max, about 50～300 MPa, which surpasses the fatigue limit. At this time micro pitting and cracking on the bush surface can be observed with SEM. When P=350 MPa, the σ max is about 300～900 MPa, the center touching area on the surface of the sample and the units around the inclusion will exceed the fatigue limit generally, the surface of the bush, the serious wear corrosion and big fatigue cracking can be observed.

关键词： finite element method includsion fatigue strength

Automorphisms with order three of affine Lie algebras

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Chinese Science Bulletin 1998年第21期43卷 1793-1798页

作者： JIN Quanqin 1,2.and HOU Zixin 2.1. Department of Mathematics, Hebei university, Baoding 071002. china 2. Department of Mathematics, Nankai university, Tianjin 300071, china Department of Mathematics Hebei University Baoding China Department of Mathematics Nankai University Tianjin China

Some properties of automorphisms of affine Lie algebras are presented. Automorphisms with order three are classified up to conjugacy, and their fixed point sets are also computed. As a corollary, it is proved that two... 详细信息

关键词： affine Lie algebra automorphism of order three first (second) kind of automorphism.