简便实用的GPS网平差模型

采用数值微商求偏导数的方法，从而使ＧＰＳ网平差的计算模型非常简洁。选用平面坐标和大地高作为平差参数，可以方便地简化为平面网或高程网，加入地面归心数据和常规观测数据也变得十分容易。对旋转角大的地方独立坐标系，提出了处理办法。经对实测数据的处理，证明了模型的正确性     

Nonlinear ray perturbation theory with its applications to ray tracing and inversion in anisotropic media

A comprehensive approach, based on the general nonlinear ray perturbation theory (Druzhinin, 1991), is proposed for both a fast and accurate uniform asymptotic solution of forward and inverse kinematic problems in anisotropic media. It has been developed to modify the standard ray linearization procedures when they become inconsistent, by providing a predictable truncation error of ray perturbation series. The theoretical background consists in a set of recurrent expressions for the perturbations of all orders for calculating approximately the body wave phase and group velocities, polarization, travel times, ray trajectories, paraxial rays and also the slowness vectors or reflected/transmitted waves in terms of elastic tensor perturbations. We assume that any elastic medium can be used as an unperturbed medium. A total 2-D numerical testing of these expressions has been established within the transverse isotropy to verify the accuracy and convergence of perturbation series when the elastic constants are perturbed. Seismological applications to determine crack-induced anisotropy parameters on VSP travel times for the different wave types in homogeneous and horizontally layered, transversally isotropic and orthorhombic structures are also presented. A number of numerical tests shows that this method is in general stable with respect to the choice of the reference model and the errors in the input data. A proof of uniqueness is provided by an interactive analysis of the sensitivity functions, which are also used for choosing optimum source/receiver locations. Finally, software has been developed for a desktop computer and applied to interpreting specific real VSP observations as well as explaining the results of physical modelling for a 3-D crack model with the estimation of crack parameters.     

基于BISQ模型的各向同性孔隙介质弹性波三维交错网格高阶有限差分数值模拟

从BISQ模型弹性波的本构方程和运动方程出发，推导出了基于BISQ模型的各向同性孔隙介质弹性波三维高阶交错网格有限差分算法，进行了数值模拟，在低频下能看到明显的快纵波、快横波和微弱慢纵波，在高频情况下可以看到明显的快纵波、快横波、慢纵波和慢横波。在三维情况下对比了xoz、xoy、yoz平面内的波场切片，并对平行xoz平面，不同y值处的波场切片进行了对比，结果证明三维数值模拟可以从不同角度更好地反映波场的传播特性。     

高阶统计量方法在地震勘探中的应用

高阶统计量方法是研究非高斯过程，非最小相位信号和非线性系统的有力工具，其应用领域已涉及通信、地球物理、生物医学、故障诊断等。本文就近年来高阶统计量在地震勘探中的应用现状进行简要的综述，并根据高阶统计量在相关领域的应用特点展望了它在地球物理领域的应用前景。     

近红外反射光谱学在岩石矿物研究中的应用——Ⅰ．快速测定地质样品中化合水

应用近红外反射光谱学方法无损快速测定了各种地质样品中化合水。使用偏最小二乘回归法，在近红外波长范围分离出与化合水含量有关的光谱信息。大多数地质样品的近红外反射光谱估算结果与重量法吻合。实验结果表明，近红外反射光谱学测定地质样品中化合水更简单、更容易。     

THE APPLICATION OF PML BOUNDARY CODITIONS IN THE SIMULATION OF SEISMIC WAVE BY THE HIGH-ORDER STAGGERED-GRID FINITE DIFFERENCES AT THE TRANSVERSELY ISOTROPIC MEDIA

In the realm of the numerical simulation, finite difference method and finite element method are more intuitive and effective than other simulation methods. In the process of simulating seismic wave propagation, the finite differences method is widely used because of its high computational efficiency and the advantage of the algorithm is more efficient. With the demand of precision, more and more researchers have proposed more effective methods of finite differences, such as the high-order staggered-grid finite differences method, which can restore the actual process of wave propagation on the premise of ensuring accuracy and improving the efficiency of operation. In the past numerical simulation of seismic wave field, different models of isotropic medium are mostly used, but it is difficult to reflect the true layer situation. With the research demand of natural seismology and seismic exploration, the research on anisotropic media is more and more extensive. Transversely isotropic(TI)media can well simulate the seismic wave propagation in the formation medium, such as gas-bearing sandstone, mudstone, shale et al., the character of TI media is reflected by introducing the Thomsen parameters to reflect its weak anisotropy of vertical direction by using Thomson parameter. Therefore, studying the process of seismic wave propagation in TI media can restore the true information of the formation to the greatest extent, and provide a more reliable simulation basis for the numerical simulation of seismic wave propagation. In the geodynamic simulation and the numerical simulation of the seismic wave field, under the limited influence of the calculation area, if no boundary conditions are added, a strong artificial boundary reflection will be generated, which greatly reduces the validity of the simulation. In order to minimize the influence of model boundaries on the reflection of seismic waves, it is often necessary to introduce absorbing boundary conditions. At present, there are three types of absorption boundary conditions: one-way wave absorption boundary, attenuation absorption boundary, and perfectly matched layer(PML)absorption boundary. In terms of numerical simulation of seismic waves, the boundary absorption effect of PML is stronger than the first two, which is currently the most commonly used method, and it also represents the cutting-edge development direction of absorption boundary technology. The perfectly matched layer absorbing boundary is effectively applied to eliminating the reflective waves from model boundaries, but for transversely isotropic medium, the effect of the absorbing is not very well. For this reason, the elastic dynamic wave equations in transversely isotropic media are derived, and we describe a second-order accurate time, tenth-order accurate space, formulation of the Madariaga-Virieux staggered-grid finite difference methods with the perfectly matched layer(PML)are given. In addition, we have established vertical transversely isotropic(VTI)media and arbitrary inclined tilted transversely isotropic(TTI)media models, using a uniform half-space velocity model and a two-layer velocity model, respectively. By combining the actual geoscience background, we set the corresponding parameters and simulation conditions in order to make our model more research-oriented. When setting model parameters, different PML thickness, incident angle, source frequency and velocity layer models were transformed to verify the inhibition of boundary reflection effect by PML absorption boundary layer. The implementations of this simulation show that the formula is correct and for the transversely isotropic(TI)media of any angular symmetry axis, when the thickness of the PML layer reaches a certain value, the seismic wave reflection effect generated by the artificial boundary can be well suppressed, and the absorption effect of PML is not subject to changes in incident angle and wave frequency. Therefore, the results of our study indicate that our research method can be used to simulate the propagation process of seismic waves in the transversely isotropic(TI)media without being affected by the reflected waves at the model boundary to restore the actual formation information and more valuable geological research.     

高阶高通隐式滤波法及其应用

采用反射边界条件的高阶高能隐式滤波法可以有效地分离尺度，抑制边界上的虚假增幅现象，对于评价和诊断要素场极为有用。用１９９１年７月５日，６日１°×１°网格的客观分析资料，对隐式双高法试验。结果表明，分离后的中尺度系统达到预想的效果。选择合适的参数能分离出所要分离的，且中尺度系统结构清晰，风压场比较协调，可作为中尺度分析的一种有用工具。     

Time derivative of earthquake acceleration

Unlike acceleration, velocity, and displacement, the time derivative of acceleration (TDoA) of ground motion has not been extensively studied. In this paper, the basic characteristics of TDoA are evaluated based on records from the 1999 Chi-Chi, earthquake (Mw 7.6) and one of its aftershocks (Mw 6.2). It is found that the maximum TDoA at a free-field station was over 31,200 cm/s3 (31.8 g/s); and the duration of "strong" TDoA, between the first and the last time points exceeding 2,000 cm/s3 (2 g/s), was almost one minute near the epicenter area. Since ground TDoA sensors are not commonly available, the time series are calculated by direct numerical differentiation of acceleration time series. Relative error analysis shows that the error is non-transitive and total error is within 4%. The density function of TDoA amplitude, frequency content and spatial distribution of peak ground jerk (PGJ) are evaluated. The study also includes examination of some TDoA responses from a seven-story building and comparison of ground TDoA with the limit TDoA used in the transportation industry for ride comfort. Some potential impacts of TDoA on humans have also been reviewed.     

地理学多视角研究方法——Braess网络车流分配过程的理论分析与数值计算

对复杂的地理系统采用多种方法从不同的视角开展分析,可以降低错误结论的概率。本文以Braess交通网络为例,提出一个地理系统多视角分析的研究案例。首先借助La氏乘数法预测奇对称Braess网络的车流优化分配的结果。然后采用数值计算和模拟方法论证,在该网络中,车流会通过自组织过程自动向着优化分配的方向演化,并且利用Markov链预测各个阶段的车流分配数值。最后借助最大熵原理从理论上证明,上述最优化过程的本质是地理系统的熵最大化;运用对偶规划和对称思想揭示,熵最大化的实质是车流运行的耗时总量最小。不同的方法给出的结果殊途同归、互相印证。这一套研究方法可以推广到多维不对称的交通网络,进而推广应用于地理学其他方面的理论分析和应用研究。     

岩体黏弹性蠕变计算的高阶数值流形法研究

数值流形法（numerical manifold method）是一种新型的数值计算方法,已成功应用于岩土工程的诸多领域,但该方法尚未应用于岩土工程蠕变分析。近年来对高阶流形法的研究表明,对复杂的岩土工程问题,使用高阶覆盖函数可明显提高流形法的计算精度。为此,开展了用高阶流形法模拟蠕变的研究,在高阶流形法中引入“时步-初应变”法计算蠕变,以广义开尔文体为基础,推导了相关的计算公式,并编制了相应的计算程序,同时还通过算例,验证了方法的可行性和合理性。结果表明,高阶流形可以方便地与“时步-初应变”法结合用于蠕变计算,可较好地模拟蠕变变形。算例分析表明,在不改变网格密度情况下,仅通过采用高阶覆盖函数,高阶流形法可大幅提高传统流形法的计算精度。