由相叠低分辨投影数据重建高分辨图像

本文提出了由平行的相叠低分辨投影数据重建高分辨图像的两个新算法，即虚拟探测器法和直接重建法，并给出和分析了数值模拟结果。     

IMPLICIT NONLINEAR NORMAL MODE INITIALIZATION: A MULTIGRID APPROACH

The implicit nonlinear normal mode initialization (INMI) is applied to a tropical limited area shallow water model in spherical coordinates.The boundary condition for the INMI scheme is based on the boundary formulation of the model.The INMI scheme is found to be very efficient in suppressing spurious gravity wave oscillation and providing a well balanced initial data set for the model.The INMI scheme involves solving a number of elliptic type equations with varying complexity.and hence an efficient numerical technique is required for solving such equations.In order to make INMI computationally more attractive,we are employing the multigrid method for solving all the elliptic type equations in the INMI scheme.The numerical procedures for the development of such multigrid solvers are briefly described.     

恒定浅水流动的显式加速收敛算法

恒定浅水流动计算常较非恒定流更困难,主要原因是收敛慢.本文探讨了应用计算流体动力学中五种加速措施的可能性,并结合水流问题的特点作了相应修改.根据数值试验结果,推荐应用局部时间、残差光滑及多重网格三种方法,并通过试算确定计算稳定性许可的临界Cr和Δt值.选用适当的加速措施,可使计算量减少30%～50%乃至更多.     

自适应多重网格有限元法及在洞室稳定分析中的应用尝试

本文简述了自适应多重网格有限元方程求解算法的原理，数据结构及计算程序的实现，并列举了一个地下洞室的计算例子作为应用尝试，同时进行了相应的讨论。     

三维泊松方程数值模拟的多重网格方法

本文简要介绍了多重网格方法的基本思想和原理,然后应用多重网格(MG)方法求解三维泊松方程,网格尺度从17×17×17逐次增加至257×257×257,并与不完全Chelesky共轭梯度法(ICCG)、Gauss直接解法进行比较,结果表明,MG方法计算速度明显优于ICCG、Gauss方法,对于129×129×129网格的三维数值模拟费时43s,比ICCG法快7倍,而对于257×257×257超大型网格的三维数值模拟也仅需412s.     

AMG preconditioning for sedimentary basin simulations in Temis calculator

Basin modelling aims at reconstructing the time evolution of a sedimentary basin in order to make quantitative predictions of geological phenomena leading to hydrocarbon accumulations. It accounts for porous medium compaction, heat transfer, hydrocarbon generation and migration. These physical phenomena are modelled by partial differential equations [Schneider, F., Wolf, S., Faille, I., Pot, D. 2000. A 3D basin model for hydrocarbon potential evaluation: application to Congo offshore. Oil and Gas Science Technologie, Rev-IFP 55, 3–13] representing the mass balances of solid, fluids (water and oil) coupled with Darcy's law and a compaction law. These equations are discretized using a cell-centered Finite Volume method in space and an implicit Euler integration in time. At each time step, the resulting nonlinear system is solved using Newton's method ending up at each Newton iteration with the solution of a linear system which represents the most cpu-time-consuming part of the basin simulator.     

用多重网格法解赫姆霍兹型欧拉方程

讨论了用多重网格方法（ＭＧＭ）求解赫姆霍兹型欧拉方程第一边值的五个定解问题，并与变系数超松弛迭代法作了比较。结果表明，在相同的精度条件下，前者所需的计算时间要比后者少，时间效率比随着网格数的增加而明显提高，反映了用多重网格方法求解大型差分方程组数值解的优越性。     

A Best-Estimate Approach for Determining Self-potential Parameters Related to Simple Geometric Shaped Structures

A new approach is proposed in order to interpret field self-potential (SP) anomalies related to simple geometric-shaped models such as sphere, horizontal cylinder, and vertical cylinder. This approach is mainly based on solving a set of algebraic linear equations, and directed towards the best estimate of the three model parameters, e.g., electric dipole moment, depth, and polarization angle. Its utility and validity are demonstrated through studying and analyzing synthetic self-potential anomalies obtained by using simulated data generated from a known model and a statistical distribution with different random errors components. Being theoretically tested and proven, this approach has been consequently applied on two real field self-potential anomalies taken from Colorado and Turkey. A comparable and acceptable agreement is obtained between the results derived by the new proposed method and those deduced by other interpretation methods. Moreover, the depth obtained by such an approach is found to be very close to that obtained by drilling information.     

三个二次代数曲面的低次拼接

用计算机代数方法，研究了三个二次曲面的光滑拼接，给出了二次拼接曲面存在的判别方法，及计算拼接曲面的Matlab程序。     

A dynamical equivalent to the equilateral libration points of the earth-moon system

Consider the Earth-Moon-particle system as a Restricted Three Body Problem. There are two equilateral libration points. In the actual world system, those points are no longer relative equilibrium points mainly due to the effect of the Sun and to the noncircular motion of the Moon around the Earth. In this paper we present the problem as a perturbation of the RTBP and we look for the dynamical equivalent of L _4,5. It turns out to be a quasiperiodic orbit. It is obtained for a simplified model but the procedure to obtain it is general and can be carried out with an additional computational effort.