利用Poisson积分推导Hotine函数及Hotine公式应用问题   总被引：2，自引：0，他引：2  

李建成  晁定波 《武汉大学学报(信息科学版)》2003,(Z1)

给出一种直接利用改进的Poisson积分确定Hotine函数的推导 ,其中不包括函数的零阶和一阶项。讨论了Hotine公式在陆地和海洋局部重力场逼近中的应用问题。  相似文献   

高分辨率区域重力场模型DQM2000   总被引：6，自引：2，他引：6  

夏哲仁  石磐  李迎春 《武汉大学学报(信息科学版)》2003,(Z1)

基于局部积分谱权综合法 ,选择国外重力场模型OSU91A和EGM96作为基础模型 ,利用中国地域2 0′× 2 0′、1 5′× 1 5′、1 0′× 1 0′和 5′× 5′平均重力异常 ,解算了一组高分辨率地球重力场系列模型DQM2 0 0 0 ,即DQM2 0 0 0A、DQM2 0 0 0B、DQM2 0 0 0C和DQM2 0 0 0D ,其完整阶次分别为 5 40、72 0、1 0 80和 2 1 60 ,采用内部符合和外部检核的方法以评价新模型的精度。  相似文献   

积分道与基于Born散射的一维声波方程速度反演     

成谷  张宝金  马在田  曹景忠  高顺莉 《地球物理学进展》2003,18(1):122-127

基于Born散射理论，推导了适用于常速和变速背景的一维速度反演公式。与经典的Bleistein逆散射反演公式相比，本文考虑了声波在一维有限空间中的传播，选取的边界条件更合理。改进后的公式也揭示了积分道(对反射系数的积分)与绝对速度的关系，更有实用价值。  相似文献   

挡土墙地震反应非线性波动模拟   总被引：3，自引：0，他引：3  

陈学良  袁一凡 《地震工程与工程振动》2003,23(4):9-16

本文运用解耦近场非线性波动数值模拟方法研究挡土墙地震反应，为反映墙土体系在地震作用下的位移机制，引入了Desai薄层单元模拟墙土间接触面，并采用双线型本构关系作为接触面单元和土体的非线性模型，在此基础上给出了解决P—SV问题的非线性显式有限元时域递推公式，为进一步发展非线性波动数值模拟技术提供了有益经验。为验证本文方法及适用性，将数值模拟结果与Zeng，X．和Madabhushi，X．P．G．等的离心机试验和弹塑性数值模拟结果进行对比。结果表明：墙土体系加速度、挡土墙顶底相对滑移、沉降和墙体倾角等同离心机试验模拟结果基本吻合，与弹塑性数值模拟结果相似。  相似文献   

积分方程法研究均质地基中单桩的工程性状     

梁发云  陈龙珠  李镜培 《岩土力学》2004,25(Z2):130-133

采用积分变换方法求解弹性半空间中圆形荷载的基本解,按照虚拟桩法建立分析模型,基于圆形荷载的基本解推导出单桩分析的第二类Fredholm积分方程,对其进行数值计算求得桩身各点处的轴力、剪力和位移等,与经典的弹性解答相比,本文的理论更为严密.通过对单桩的荷载传递、沉降特性以及临界桩长等问题的参数分析,得出一些具有工程应用价值的结论.  相似文献   

Spherical harmonics in texture analysis   总被引：1，自引：0，他引：1  

Helmut Schaeben  K. Gerald van den Boogaart 《Tectonophysics》2003,370(1-4):253-268

The objective of this contribution is to emphasize the fundamental role of spherical harmonics in constructive approximation on the sphere in general and in texture analysis in particular. The specific purpose is to present some methods of texture analysis and pole-to-orientation probability density inversion in a unifying approach, i.e. to show that the classic harmonic method, the pole density component fit method initially introduced as a distinct alternative, and the spherical wavelet method for high-resolution texture analysis share a common mathematical basis provided by spherical harmonics. Since pole probability density functions and orientation probability density functions are probability density functions defined on the sphere Ω^{3 3} or hypersphere Ω^{4 4}, respectively, they belong at least to the space of measurable and integrable functions ¹(Ω^d), d=3, 4, respectively.

Therefore, first a basic and simplified method to derive real symmetrized spherical harmonics with the mathematical property of providing a representation of rotations or orientations, respectively, is presented. Then, standard orientation or pole probability density functions, respectively, are introduced by summation processes of harmonic series expansions of ¹(Ω^d) functions, thus avoiding resorting to intuition and heuristics. Eventually, it is shown how a rearrangement of the harmonics leads quite canonically to spherical wavelets, which provide a method for high-resolution texture analysis. This unified point of view clarifies how these methods, e.g. standard functions, apply to texture analysis of EBSD orientation measurements.  相似文献   

Numerical modelling of seismic waves scattered by hydrofractures: application of the indirect boundary element method   总被引：2，自引：0，他引：2  

Tim Pointer  Enru Liu  & John A. Hudson 《Geophysical Journal International》1998,135(1):289-303

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An elliptic problem with integral constraints with application to large-scale geophysical flows     

A.J. Meir  Irad Yavneh 《Computational Geosciences》1998,2(4):337-346

We present a weak formulation of a non-standard elliptic equation whose boundary values are determined in part by integral relations. Existence and uniqueness of its solution are proved, and a finite element discretization is described, analyzed, and implemented on a test problem. The equation is a generalization of one that is solved during integration of the three-dimensional Quasigeostrophic equations, which model large-scale rotating stratified flows, where the integral constraints represent conservation of physical properties.  相似文献   

Surface-wave polarization data and global anisotropic structure   总被引：1，自引：0，他引：1  

G. Laske  & G. Masters 《Geophysical Journal International》1998,132(3):508-520

In the past few years, seismic tomography has begun to provide detailed images of seismic velocity in the Earth's interior which, for the first time, give direct observational constraints on the mechanisms of heat and mass transfer. The study of surface waves has led to quite detailed maps of upper-mantle structure, and the current global models agree reasonably well down to wavelengths of approximately 2000 km. Usually, the models contain only elastic isotropic structure, which provides an excellent fit to the data in most cases. For example, the variance reduction for minor and major arc phase data in the frequency range 7–15 mHz is typically 65–92 per cent and the data are fit to within 1–2 standard deviations. The fit to great-circle phase data, which are not subject to bias from unknown source or instrument effects, is even better. However, there is clear evidence for seismic anisotropy in various places on the globe. This study demonstrates how much (or little) the fit to the data is improved by including anisotropy in the modelling process. It also illuminates some of the trade-offs between isotropic and anisotropic structure and gives an estimate of how much bias is introduced by neglecting anisotropy. Finally, we show that the addition of polarization data has the potential for improving recovery of anisotropic structure by diminishing the trade-offs between isotropic and anisotropic effects.  相似文献   

广义纵弯褶皱叠加机制、类型及其应用   总被引：1，自引：0，他引：1  

杜思清  魏显贵  刘援朝 《矿物岩石》1998,(Z1)

早期褶皱的迁移机制和迁移型叠加类型的发现扩大了对广义纵弯褶皱叠加机制和类型的认识。广义叠加机制有多种,其中包括迁移和位移,褶皱变缓和展平,岩层变陡和变缓等。广义叠加类型中除基本类型外还有限制型、展平残留型、叠加挠曲、共轴重褶等。本文将用几个地质实例予以说明。此外还将讨论叠加褶皱层应变和小构造的多成因和应用问题,其中包括斜纵弯应变和褶皱变缓展平引起的应变和小构造。  相似文献