增量破坏型机动安定性分析方法及其应用

根据避免累积塑性变形发生的安定准则，构造了相应的安定性数值求解方法，进而用于确定海洋平台地基的安定荷载上限近似解，为评价地基在复杂变值荷载作用下的承载力提供了依据。     

The diffraction of linear waves by a uniform vertical cylinder with cosine-type radial perturbations

The interaction of linear waves with a uniform, bottom-mounted, surface-piercing cylinder whose diameter exhibits a cosine-type variation is investigated. Two solution methods are presented. One method is based on a perturbation theory, using a perturbation parameter defined in terms of the surface geometry of the cylinder. The analysis includes terms up to the first-order in this parameter, where the zeroth-order solution corresponds to a circular cylinder. The velocity potentials at the zeroth and first orders are expressed as eigenfunction expansions involving unknown coefficients that are subsequently determined through the cylinder boundary conditions. The second method is based on Green's theorem and gives rise to an integral equation for the fluid velocity potential on the cylinder surface. A comparison between the results of these two methods has proved that they are in good agreement for small values of the perturbation parameter. Numerical results are presented that illustrate the influence of the magnitude and frequency of these perturbations on the resulting hydrodynamic force and the wave runup on the cylinder.     

不变子空间上特征值的摄动(英文)

本文推广Wielandt—Hoffman定理而得到如下结果:定理1: 设A=X_Adiag(λ_1~((A)),…,λ_n~((A)))X_A~(-1),Q_1∈C~(n×m),T=X_Tdiag万吨(λ_1~((T)),…,λ_m~((T)))X_T~(-1),m≤n。那么,存在1,2,…,n的某个排列π(1),…,π(n)使得:其中,K_2(C)=‖C‖_2‖C~(-1)‖_2,‖‖_2及‖‖_F分别代表矩阵的谱范数和Frobcnius范数,σ_(min)(Q_1)是矩阵Q_1的最小奇异值。     

Dynamic Response of Ocean Trestle to Horizontal Impact of Moving Mass

Based on the Winkler hypothesis, a model for analysis of the flexural response of an ocean trestle embedded in layered soil to horizontal impact of a moving mass is developed. By use of the transfer matrix in time domain, one can calculate the flexural dynamic response of a single pile. Then, by use of the boundary conditions of piles at the pile top, the dynamic response of the structure is analyzed. By use of the model proposed in this paper, the interactive force between the moving mass and the structure can be computed based on Work' s kinetic energy theorem and Newton iterative method. Thus the approach does not have to assume the interactive force, while the traditional method have to. The approach more accords with the engineering practice than the traditional method and it is convenient for engineering design.     

Analysis of Wave Directional Spreading by Bayesian Parameter Estimation

A spatial array of wave gauges installed on an observatoion platform has been designed and arranged to measure the lo-cal features of winter monsoon directional waves off Taishi coast of Taiwan. A new method, named the Bayesian Parameter Estimation Method(BPEM) , is developed and adopted to determine the main direction and the directional spreading parame-ter of directional spectra. The BPEM could be considered as a regression analysis to find the maximum joint probability of parameters, which best approximates the observed data from the Bayesian viewpoint. The result of the analysis of field wave data demonstrates the highly dependency of the characteristics of normalized directional spreading on the wave age. The Mit-suyasu type empirical formula of directional spectrum is therefore modified to be representative of monsoon wave field. More-over, it is suggested that Smax could be expressed as a function of wave steepness. The values of Smax decrease with increas-ing steepness. Finally, a local directi     

Reciprocal theorems in structural dynamics including initial conditions

For completeness purposes, as well as for practical reasons, this work investigates the well‐known Betti–Rayleigh reciprocal theorem for structural dynamics in a way which includes the effect of initial conditions. It then presents a natural and consistent way for introducing the Duhamel integral for the transient response of a dynamical system through the aforementioned reciprocal theorem. Copyright © 2005 John Wiley & Sons, Ltd.     

高空间分辨率影像和多光谱影像融合的研究

从卫星影像的成像过程出发 ,揭示了卫星影像所含信息的物理内涵 ,从频率域特性出发得出了高空间分辨率影像和多光谱影像可以融合的物理基础 ,为寻找一种较好的融合方法提供了理论依据。     

Green's function solution to spherical gradiometric boundary-value problems

 Three independent gradiometric boundary-value problems (BVPs) with three types of gradiometric data, {Γ _rr }, {Γ _{r θ},Γ _{r λ}} and {Γ_θθ−Γ_λλ,Γ_θλ}, prescribed on a sphere are solved to determine the gravitational potential on and outside the sphere. The existence and uniqueness conditions on the solutions are formulated showing that the zero- and the first-degree spherical harmonics are to be removed from {Γ _{r θ},Γ _{r λ}} and {Γ_θθ−Γ_λλ,Γ_θλ}, respectively. The solutions to the gradiometric BVPs are presented in terms of Green's functions, which are expressed in both spectral and closed spatial forms. The logarithmic singularity of the Green's function at the point ψ=0 is investigated for the component Γ _rr . The other two Green's functions are finite at this point. Comparisons to the paper by van Gelderen and Rummel [Journal of Geodesy (2001) 75: 1–11] show that the presented solution refines the former solution. Received: 3 October 2001 / Accepted: 4 October 2002     

基于模糊随机理论的广义可靠度在边坡稳定性分析中的应用

在常规的概率极限状态理论基础上 ,分析了边坡体安全状态的模糊性 ,在此基础上构造了基于MCS以及FORM算法的模糊随机可靠度算法 ,分别就边坡体的滑动失效、渗透破坏两种失效模式作了参数敏感性分析 ,并进一步对边坡体的系统失效模式作了探讨     

采样率不足引起的反应谱计算误差

本文从分析谐波的反应谱计算误差及其产生原因入手,研究了常规反应谱方法的计算误差,指出选择采样率不仅要参照信号的奈奎斯特频率,还要注意使用采样数据时恢复被采信号所用的内插方法和容许的内插误差,文中强调山农采样定理所说的采样率大于２倍奈奎斯特频率时可完全恢复被采信号是针对内插函数ｈａ（ｔ－ｎ．Ｔ）而言的,文中以用典型的加速度反应谱合成的５条地震加速度里程及一系列谐波里程为例,研究了由于采样率不足而引起