IKONOS卫星影像立体测图中有理函数模型的研究

有理函数模型是成像几何模型的一种简单、通用的表达,已经成为构筑真实传感器模型的一个计算方法.本文对IKONOS卫星影像立体测图作了介绍.详细介绍了IKONOS图像的有理函数模型的理论、算法、各种特性以及如何对其进行优化.     

Interaction of ocean waves with floating and submerged horizontal flexible structures in three-dimensions

A three-dimensional general mathematical hydroelastic model dealing with the problem of wave interaction with a floating and a submerged flexible structure is developed based on small amplitude wave theory and linear structural response. The horizontal floating and submerged flexible structures are modelled with a thin plate theory. The linearized long wave equations based on shallow water approximations are derived and results are compared. Three-dimensional Green’s functions are derived using fundamental source potentials in water of finite and infinite depths. The expansion formulae associated with orthogonal mode-coupling relations are derived based on the application of Fourier transform in finite and infinite depths in case of finite width in three-dimensions. The usefulness of the expansion formula is demonstrated by analysing a physical problem of surface gravity wave interaction with a moored finite floating elastic plate in the presence of a finite submerged flexible membrane in three-dimensions. The numerical accuracy of the method is demonstrated by computing the complex values of reflected wave amplitudes for different modes of oscillation and mooring stiffness. Further, the effect of compressive force and modes of oscillations on a free oscillation hydroelastic waves in a closed channel of finite width and length for floating and submerged elastic plate system is analysed.     

潜堤结构型式及其透射系数研究

针对胜利油田某保滩促淤工程，进行了多种方案不同潜堤结构型式的优选，比较了其中四种结构型式，并对这四种结构型式的潜堤分别进行了波浪水槽试验，测试其透射系数，在此基础上，给出了计算潜堤透射系数的经验公式，为工程设计提供依据。     

Implementation of the finite element method in the three‐dimensional discontinuous deformation analysis (3D‐DDA)

A modified three‐dimensional discontinuous deformation analysis (3D‐DDA) method is derived using four‐noded tetrahedral elements to improve the accuracy of current 3D‐DDA algorithm in practical applications. The analysis program for the modified 3D‐DDA method is developed in a C++ environment and its accuracy is illustrated through comparisons with several analytical solutions that are available for selected problems. The predicted solutions for these problems using the modified 3D‐DDA approach all show satisfactory agreement with the corresponding analytical results. Results presented in this paper demonstrate that the modified 3D‐DDA method with discontinuous modeling capabilities offers a useful computational tool to determine stresses and deformations in practical problems involving fissured elastic media with reasonable accuracy. Copyright © 2008 John Wiley & Sons, Ltd.     

Local problem-based <Emphasis Type="Italic">a posteriori</Emphasis> error estimators for discontinuous Galerkin approximations of reactive transport

We consider adaptive discontinuous Galerkin (DG) methods for solving reactive transport problems in porous media. To guide anisotropic and dynamic mesh adaptation, a posteriori error estimators based on solving local problems are established. These error estimators are efficient to compute and effective to capture local phenomena, and they apply to all the four primal DG schemes, namely, symmetric interior penalty Galerkin, nonsymmetric interior penalty Galerkin, incomplete interior penalty Galerkin, and the Oden–Babuška-Baumann version of DG. Numerical results are provided to illustrate the effectiveness of the proposed error estimators.     

Site coefficients suitable to China site category

Introduction Site effect on strong earthquake ground motion is an important problem for seismologists and earthquake engineers. The direct approach to study site effect is to use data from a vertical array of seismometers, which is called borehole station…     

An isostatically compensated gravity model using spherical layer distributions

A new isostatic model for the Earths gravity field is presented based on a simple hypothesis of layers approximating constant density contrasts. The spherical layer distribution used to describe the hydrostatic equilibrium of the Earths masses leads to a new set of spherical harmonic coefficients for the gravitational potential. First attempts to quantify the information content of these coefficients led to the outcome that they seem to explain the observed gravity field for a certain wavelength band, while they are insufficient for short and very long wavelengths. A synthesis of the derived coefficients over specific degree ranges provided a computation of band-limited geoid undulations on a global scale. The association of these potential quantities with known tectonic structures, such as the topography of the core–mantle boundary, strengthens the belief that the interpretation of Earth gravity models, especially those arising from global digital elevation models, should be considered in close relation with deep-Earth structure.     

Slotting of borehole sequences

A method is described for comparing and correlating borehole sequences using information from one or more physical logs recorded from the boreholes. The method is illustrated by a small worked example. Ways are described whereby constraints may be imposed on the comparison to allow the incorporation of relevant information, such as the presence of marker beds in the stratigraphic sequences. An account is given of the comparison of three boreholes in the Lansing Group of Kansas, USA, and there is a short discussion on the effects of filtering, standardizing, and weighting the logs.     

Molecular Line Parameters for the “MASTER” (Millimeter Wave Acquisitions for Stratosphere/Troposphere Exchange Research) Database

In order to investigate the upper troposphere/lower stratosphere (UTLS) region of the earth's atmosphere, ESA/ESTEC (European space agency) is considering the opportunity to develop the spaceborne limb sounding millimeter sensor “MASTER” (millimeter wave acquisitions for stratosphere/troposphere exchange research). This instrument is part of the “atmospheric composition explorer for chemistry and climate interactions” (ACECHEM) project. In addition, ESA/ESTEC is developing the “MARSCHALS” (millimeter-wave airborne receiver for spectroscopic characterization of atmospheric limb sounding) airborne instrument which will demonstrate the feasibility of MASTER. The present paper describes the line-by-line database which was generated in order to meet at best the needs of the MASTER (or MARSCHALS) instrument. The linelist involves line positions, line intensities, line broadening and line shift parameters in the 294–305, 316–325, 342–348, 497–506 and 624–626 GHz spectral microwindows. This database was first generated for the target molecules for MASTER (H₂O, O₃, N₂O, CO, O₂, HNO₃, HCl, ClO, CH₃Cl, BrO). In addition, ten additional molecules (SO₂, NO₂, OCS, H₂CO, HOCl, HCN, H₂O₂, COF₂, HO₂ and HOBr) had also to be considered in the database as “possible interfering species” for the retrieval of the target molecules of MASTER. The line parameters were derived, depending on their estimated accuracy, (i) from a combination of spectral parameters included in the JPL and HITRAN catalogs (ii) from data taken into the literature or (iii) using data obtained through experimental measurements (and/or) calculations performed during the present study.