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china Textile 2024年第4期 20-21页

作者： china Daily

The robust demand of the Chinese market and the improving business environment in the country make china a big growth opportunity for companies wishing to further expand their operations,said corporates that have registered to participate at this year's china International Import *** 7th edition of the annual CIIE,to be held in Shanghai from Nov 5 to 10,started its 100-day countdown on Saturday.

关键词： companies likely operations

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A STUDY OF OSCILLATING FLOWS OVEr prOpAGATING rIppLES:pArT Ⅱ. VOrTICITY DYNAMICS

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Journal of Hydrodynamics 2000年第1期12卷 8-15页

作者： Lu Xi yun department of Modern mechanics, University of Science and Technology of china, Hefei 230026, p.r.china Univ of Science and Technology of China Hefei China

Vortex shedding for an oscillating flow over ripples is numerically investigated by solving 2 D time dependent incompressible Navier Stokes equations in curvilinear coordinates. The dynamics of vortex structures generated by flow separation is studied in order to understand some phenomena which take place near the bottom and in particular to get insight into the mechanism through which sediment grains are lifted up and maintained in suspension. Based on our calculated results, some important phenomena, such as vortex shedding, vortices pairing, vortices coalescence, vortex interaction with the free shear layer and so on, can be found. The behaviors of energy dissipation in the flow field and of shear stress along the ripple surface are also discussed for studying the dynamics of sediment grains in suspension and to obtain new information on the suspended load over the ripples.

关键词： oscillating flow ripple vorticity dynamics separation flow

STOCHASTIC prOpAGATION OF SEMI-ELLIpTICAL SUrFACE CrACK

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Acta Mechanica Solida Sinica 1995年第3期8卷 236-244页

作者： Zhu Weiqiu Jiang Mingxiao (department of mechanics,Zhejiang University,Hangzhou,310027,p.r.china) department of mechanics Zhejiang University Hangzhou 310027 China

The semi-elliptical surface crack growth of structural components with uncertain material resistance under random loading is studied by using the stochastic averaging *** FpK equation governing the transition probability density function of crack lengths is *** analytical solution of the FpK equation for the case of that the equations for the crack growth in the surface and depth directions are uncoupled is *** effects of the parameters of the stress process and of the material property on the behavior of semi-elliptical fatigue crack growth of the components with deterministic resistance to crack growth in the stationary Gaussian stress process are *** comparison of the analytical result with digital simulation shows the effectiveness of the present method.

关键词： fatigue crack growth semi-elliptical surface crack fatigue life reliability stochastic averaging

LINEAr ACTIVE STrUCTUrES AND MODES (Ⅱ) —DISCrETE SYSTEMS AND BEAMS

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Applied Mathematics and mechanics(English Edition) 2004年第8期25卷 854-862页

作者：王永刚龚靖School of Civil Engineering and mechanics Xi'an Jiaotong University Xi'an 710049 p.r.china department of Civil Engineering Northeast china Institute of Electric power Jilin 132012 p.r.china 张景绘School of Civil Engineering and mechanics Xi'an Jiaotong University Xi'an 710049 p.r.china School of Civil Engineering and mechanics Xi'an Jiaotong University Xi'an 710049 P.R.ChinaSchool of Science Chang'an University Xi'an 710064 P.R.China

The basic concepts about the active structures and some attributes of the modes were presented in paper “Liner Active Structures and Modes]( I) ". The characteristics of the active discrete systems and active beams were discussed, especially, the stability of the active structures and the orthogonality of the eigenvectors. The notes about modes were portrayed by a model of a seven-storeyed building with sensors and actuators. The concept of the adjoint active structure was extended from the discrete systems to the beams that were the representations of the continuous structures. Two types of beams with different placements of the measuring and actuating systems were discussed in detail. One is the beam with the discrete sensors and actuators, and the other is the beam with distributed sensor and actuator function. The orthogonality conditions were derived with the modal shapes of the active beam and its adjoint active beam. An example shows that the variation of eigenvalues with feedback amplitude for the homo-configuration and non-homo-configuration active structures.

关键词： I) ". The characteristics of the active discrete systems and active beams were discussed especially the stability of the active structures and the orthogonality of the eigenvectors. The notes about modes were portrayed by a model of a seven-s

Serving High-Level Opening up with "TaxExpress"

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Belt and road Initiative Tax Journal 2024年第1期 97-105页

作者： International Taxation department, State Taxation Administration,the people's republic of china International Taxation department State Taxation Administrationthe People's Republic of China

Over the past decade,the Chinese tax authorities have been actively supporting the development of the Belt and road Initiative,by creating a unique cross-border tax and fee service model with Chinese characteristics,which has laid a solid foundation for the establishment of the "TaxExpress" cross-border service *** October 2023,the State Taxation Administration of china(STA) officially launched the "TaxExpress" brand,focusing on one service matrix,two service teams,three service mechanisms,and four knowledge *** brand aims to enhance cooperation between ministries and commissions,promote international exchanges,and establish a framework for effective cross-border tax and fee *** forward,the STA will continue to leverage existing resources to support high-level opening up,by enhancing brand value,improving measures for international tax and fee services,expanding cross-border tax and fee services,strengthening professional talent teams,so as to develop a cross-border tax and fee service system that combines Chinese characteristics with international best practices.

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THE FLOW IN rOTATING CUrVED CIrCULAr pIpE

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Journal of Hydrodynamics 2000年第1期12卷 108-116页

作者： Zhang Jin suo, Shen Xin rong, Zhang Ben zhao department of mechanics, Zhejiang University, Hangzhou 310027, p.r.china Zhejiang Univ Hangzhou China

The combined effects of the system rotation (Coriolis force) and curvature (centrifugal force) on the flow in rotating curved circular pipe with small curvature are examined by perturbation method. A second order perturbation solution is presented. The secondary flow structure and the primary axial velocity distributions are studied in detail. The loops of the secondary flow are more complex than those in a curved pipe without rotation or a rotating straight pipe. Its numbers depend on the body force ratio F which represents the ratio of the Coriolis to the centrifugal force. The maximum of the axial velocity is pushed to either outer bend or inner bend, which is also determined by F. The results are confirmed by the results of other authors who studied the same problem by different methods.

关键词： secondary flow curved pipe perturbation method

THE rOTATIONALLY pErIODIC SYMMETrY IN BEM

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Acta Mechanica Solida Sinica 1994年第3期7卷 235-244页

作者： Yang Haitian (department of Engineering mechanics,Dalian University of Technology,p.r.china)Wu Gaofeng Wu Jingning (research Institute of Engineering mechanics,Dalian University of Technology,p.r.china) department of Engineering mechanics Dalian University of Technology China research Institute of Engineering mechanics Dalian University of Technology China

rotationally periodic symmetry is exploited in 2-D elastostatic calculation using the *** is proved that the coefficient matrices of the global boundary element equations for the rotationally periodic system are block-circulant so long as a kind of symmetry-adapted reference coordinate system is adopted. Furthermore,an efficient algorithm,which partitions the original problem of solving the boundary element equations into a series of subproblems,is *** method permits arbitrary load distribution for stress analysis problems.

关键词： rotationally periodic symmetry boundary element

LINEAr ACTIVE STrUCTUrES AND MODES (Ⅰ) —BASIC CONCEpTS AND prOpErTIES

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Applied Mathematics and mechanics(English Edition) 2004年第8期25卷 845-853页

作者：张景绘龚靖School of Civil Engineering and mechanics Xi'an Jiaotong University Xi'an 710049 p.r.china department of Civil Engineering Northeast china Institute of Electric power Jilin 132012 p.r.china 王永刚School of Civil Engineering and mechanics Xi'an Jiaotong University Xi'an 710049 p.r.china School of Science Chang'an University Xi'an 710064 p.r.china School of Civil Engineering and mechanics Xi'an Jiaotong University Xi'an 710049 P.R.China

Some basic concepts about the active structures were firstly explained, and the main subjects to study in the field of active structure dynamics were synthesized. For the linear active structures, the annotations on the modes were done in detail. The physical meanings of the right and left eigenvectors were explained. The right eigenvectors are the modal shapes and the modal responses of an active structure depend on the left ones. The adjoint structure of an active structure was defined and the reciprocity theorem was interpreted. For two active structures, which are adjoint to each other and with the reciprocal gain-matrices, the right and left eigenvector are reciprocal. The relationship between an active structure and the corresponding passive structure is expressed with the transfer functions, which is employed to resolve the estimation problems.

关键词： active structure vibration control smart structure mode

THE DAMAGE STATES AND TENSILE FAILUrE BEHAVIOr OF TOrSIONAL prESTrAINED STEELS

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Acta Mechanica Solida Sinica 1994年第3期7卷 229-234页

作者： zhou li(department of Applied mechanics,Northwestern polytechnical University,Xi’an,710072,p.r.china) department of Applied mechanics Northwestern Polytechnical University Xian 710072 China

In this paper,the damage state of a torsional prestrained steel is examined by means of the concepts of continuum damage mechanics and then the tensile properties and fracture ductility of two kinds of steels under various torsional prestrained conditions are investigated from both macroscopic and microscopic points of very slight as contrasted with tensile damage;(2)after torsional prestraining,both yielding strength and ultimate tensile strength become higher for 20 steel and lower for 40Cr steel;(3)when the torsional prestrain exceeds a critical value,that is about 70% of pure torsional shear fracture strain,the ductile-brittle transition of tensile fracture behavior may ***,the advantages and applicable conditions of torsional prestrain strengthening technique are also discussed.

关键词： torsional prestrain plastic damage tensile failure ductile-brittle transition