检索结果-南通市图书馆

DYNAMIC SIMULATION OF ROTATING SHELLS COUPLED WITH LIQUID

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2001年第2期14卷 169-175页

作者： Wei Fayuan Li Shiqi Huang Yuying~1 Zhong Yifang (College of Mechanical science and Engineering, huazhong university of science and technology, {2., china) (1 department of mechanics, huazhong university of science and technology, {2.,china) ***

The dynamic behaviors of rotating shells coupled with liquid areshown. The shell under con- sideration has arbitrary boundaryconditions and a complex shape. A modified boundary element methodand finite strip technique are used to improve the computingefficiency and to guarantee the continuity conditions on theliquid-shell interaction plane. The effects of various parameterssuch as shell's thickness and liquid depth are investigated. Dynamicsimulations are applied to several typical shell-liquid systems, andthe natu- ral frequencies, mode shapes and response of vibration arecalculated numerically.

关键词： rotting shells dynamic simulation fluid-solid interaction

BOUNDARY VALUE PROBLEMS OF TWO-DIMENSIONAL ANISOTROPIC BODY WITH A PARABOLIC BOUNDARY

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 1996年第2期9卷 139-150页

作者： Hu Yuantai Huang Yuying Zhong Weifang, department of mechanics, {2., wuhan 430074 huazhong UNIV SCI & TECHNOL DEPT MECHWUHAN 430074PEOPLES R CHINA

Based upon Stroh formalism we derive a novel and convenient scheme for determining the elastic fields of a two-dimensional anisotropic body with a parabolic boundary subject to two kinds of boundary conditions, which are free surface and rigid surface, respectively. The corresponding Green's functions are found by using the conformal mapping method. When the parabolic curve degenerates into a half-infinite crack or rigid inclusion, the singular stress fields near the tip of defects ark obtained. In particular, those Green's functions for a concentrated moment M(0) applied at a point on the parabolic curve are also studied. It is easily found that arbitrary parabolic boundary value problems can be solved by using these Green's functions and associate integrals.

关键词： Stroh formalism eigenvalue stress intensity factor

NONLINEAR STABILITY OF NATURAL RUNGE-KUTTA METHODS FOR NEUTRAL DELAY DIFFERENTIAL EQUATIONS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2002年第6期20卷 583-590页

作者： Cheng-jian Zhang(department of Mathematics, huazhong university of science and technology, {2., Hubei, P. R. china) department of Mathematics Huazhong University of Science and Technology Wuhan 430074

Presents the stability analysis of theoretical solutions for a class of nonlinear neutral delay-differential equations (NDDE). Discussion on the numerical analogous results of the natural Runge-Kutta (NRK) methods for the same class of nonlinear NDDE; Review of the related concepts and results on RK methods; Information on the asymptotic stability and global stability of the induced NRK method.

关键词： nonlinear stability neutral delay differential equations natural Runge-Kutta methods

Structure and Magnetic Properties of Ni-doped ZnO Powder

在线全文

学校读者我要写书评

暂无评论

Journal of wuhan university of {2.(Materials science) 2010年第5期25卷 770-773页

作者：高放赵俊 department of Electronic science and {2. Huazhong University of Science and Technology

Ni-doped ZnO nanopowder （Zn0.98Ni0.2.） was synthesized by improved coprecipitation method. The average particle size of the powder was estimated to be 50 nm. The powder was then processed by thermal treatment. Samples were annealed at 1 073, 1 2.3, and 1 473 K, respectively. The solubility of NiO in ZnO and the lattice parameters of ZnO both increased with the temperature. The magnetic property of the doped samples was examined, and hysteresis loops were got. The results showed all the samples were ferromagnetic, while powder processed at 1 2.3 K for 4 h got a highest saturation magnetization （Ms） of 0.0457 emu/g. Also, magnetic properties were related to the grain size of the powder.

关键词： ferromagnetism diluted magnetic semiconductor Ni-doped ZnO coprecipitation solid state reaction

Applications of semigroups of operators to non-elliptic differential operators

在线全文

学校读者我要写书评

暂无评论

Chinese science Bulletin 2000年第8期45卷 673-682页

作者： ZHENG Quandepartment of Mathematics, huazhong university of science and technology, {2., china department of Mathematics Huazhong University of Science and Technology Wuhan China

This paper treats systematically the semigroup method of non-elliptic differential operators, which was developed in the last ten years. In particular, a review of the applications of regularized semigroups to non-elliptic differential operators with constant coefficients or time-dependent coefficients, parabolic systems, correct systems, abstract differential operators and pseudodifferential operators is given here. It is also shown that the regularized semigroup is an appropriate tool for non-elliptic differential operators and is far superior to the integrated semigroup approach.

关键词： differential operator regularized semigroup integrated semigroup initial value problem Fourier multiplier.

Exact eigenstates for a class of models describing multiphoton processes in the presence of seven bosonic modes

在线全文

学校读者我要写书评

暂无评论

science china(Physics,{2. & Astronomy) 2004年第6期47卷 649-657页

作者： ZHAN Zhiming1,LI Weibin2.YOU Jun2.XIE Xiaotao2.& YANG Wenxing2.1.State Key Laboratory of Laser technology,huazhong university of science and technology,{2.,china 2.department of Physics,huazhong university of science and technology,{2.,china 1. State Key Laboratory of Laser technology Huazhong University of Science and Technology 430074 Wuhan China 2. department of Physics Huazhong University of Science and Technology 430074 Wuhan China

We present the analytical expressions of eigenstates and eigenenergies by using a parameter λ without the assumption of Bethe anzatz for three kinds of seven-bosonic-mode mixing models. The parameter is shown to be determined by the roots of a simple polynomial. We also demonstrate the exact analytical expressions of eigenstates and energies without any unknown parameter.

关键词： spectra, eigenstate, eigenvalue.

A SEMI-ANALYTICAL AND SEMI-NUMERICAL METHOD FOR SOLVING 2.D SOUND-STRUCTURE INTERACTION PROBLEMS

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2003年第2期16卷 116-126页

作者： Xiang Yu Huang Yuying (College of Civil Engineering and mechanics,huazhong university of science and technology,{2.,china) CollegeofCivilEngineeringandmechanics HuazhongUniversityofScienceandTechnologyWuhan430074China

Based on the transfer matrix method and the virtual source simulation technique, this paper proposes a novel semi-analytical and semi-numerical method for solving 2.D sound- structure interaction problems under a harmonic *** any integration segment, as long as its length is small enough,along the circumferential curvilinear coordinate,the non- homogeneous matrix differential equation of an elastic ring of complex geometrical shape can be rewritten in terms of the homogeneous one by the method of extended homogeneous capacity proposed in this *** the exterior fluid domain,the multi-circular virtual source simulation technique is *** source density distributed on each virtual circular curve may be ex- panded as the Fourier's *** with the inverse fast Fourier transformation,a higher accuracy and efficiency method for solving 2.D exterior Helmholtz's problems is presented in this *** the aspect of solution to the coupling equations,the state vectors of elastic ring induced by the given harmonic excitation and generalized forces of coefficients of the Fourier series can be obtained respectively by using a high precision integration scheme combined with the method of extended homogeneous capacity put forward in this *** to the superposition princi- ple and compatibility conditions at the interface between the elastic ring and fluid,the algebraic equation of system can be directly constructed by using the least square *** of acoustic radiation from two typical fluid-loaded elastic rings under a harmonic concentrated force are *** results show that the method proposed is more efficient than the mixed FE-BE method in common use.

关键词： sound-structure interaction acoustic radiatlon multi-circular virtual source simulation technique transfer matrix method inverse fast Fourier transformation semi-analytical and semi-numerical method

Simulation of the Earth' s gravitational field recovery from GRACE using the energy balance approach

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2005年第7期15卷 596-601页

作者： ZHENG Wei, LU Xiaolei, HSU Houtse, SHAO Chenggang, LUO Jun and WANG Nengchao ( department of Physics, huazhong university of science and technology, {2., china Institute of Geodesy and Geophysics, Chinese Academy of sciences, wuhan 430077, china department of Mathematics, huazhong university of science and technology, {2., china) department of Physics Huazhong University of Science and Technology Wuhan 430074 China. department of Mathematics Huazhong University of Science and Technology Wuhan 430074 China. Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China

Based on the measurement principles of GRACE satellites, the observation equations are set up using the energy balance approach. The Earth's gravitational field complete up to degree and order 12. is recovered applying the preconditioning conjugate gradient iterative approach by numerical simulation. Assuming an accuracy of 1 μm/s in range-rate measurements of the K-band microwave ranging system, the matching relationships of accuracies of K-band microwave ranging system, SuperSTAR Accelerometer, position vector and velocity vector measurements are investigated.

关键词： the Earth’s gravitational field GRACE satellites energy balance approach preconditioning conjugate gradient method.

1/2.SUBHARMONIC RESONANCE OF A SHAFT WITH UNSYMMETRICAL STIFFNESS

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2003年第1期16卷 25-27,30页

作者： Xiao XiwuYang Shuzi Huang Yuyingdepartment of mechanics,{2. university of scienceand technology,wuhan 430074, china department of mechanics Huzahong University of Scienceand Technology Wuhan 430074

The 1/2.subharmonic resonance of a shaft with unsymmetrical stiffness is studied. By means of the Hamilton's principle the nonlinear differential equations of motion of the rotating shaft are derived in the rotating rectangular coordinate system. Transforming the equations of motion from rotating coordinate system into stationary coordinate system and introducing a complex variable, the equation of motion in complex variable form is obtained, in which the stiffness coefficient varies periodically with time. It presents a nonlinear oscillation system under parametric excitation. By applying the method of multiple scales (MMS) the averaged equation, the bifurcating response equations and local bifurcating set are obtained. Via the theory of singularity, the stability of constant solutions is analyzed and bifurcating response curves are obtained. This study shows that the rotating shaft has rich bifurcation phenomena.

关键词： Shaft with unsymmetrical stiffiless Subharmonic resonance Stability Bifurcation MMS