矩阵广义初等变换及其运用

提出了关于分块矩阵的广义初等变换这一概念,以此为工具简化了一些复杂矩阵问题的解决方法。     

三维空间实体间拓扑关系的矩阵描述

三维空间实体及其间拓扑关系的语义描述和形式化表达是三维ＧＩＳ空间数据建模的重要理论基础。在ｋ－维流形的三维空间实体形式化描述方法的基础上,根据三维空间实体的可剖分性,采用顾及维数的九元组描述框架,研究用于构成三维实体的ｋ－单纯形（０≤ｋ≤３）之间的拓扑空间关系,继而研究三维实体间的拓扑空间关系。     

立体视觉的摄影测量理论

从引入空间投影变换的概念入手,证明了体积之交比为一般的投影不变量,从而将其作为描述物体的度量。通过对基础矩阵进行合适的分解,导出了确定投影变换模型之齐次坐标和投影坐标的方法。提出了三维直接线性变换用于由物体的投影变换模型进行物体重建。实验分析证实了所述理论和方法的正确性。     

Calculation of the Inverse of the Covariance

In reservoir characterization, the covariance is often used to describe the spatial correlation and variation in rock properties or the uncertainty in rock properties. The inverse of the covariance, on the other hand, is seldom discussed in geostatistics. In this paper, I show that the inverse is required for simulation and estimation of Gaussian random fields, and that it can be identified with the differential operator in regularized inverse theory. Unfortunately, because the covariance matrix for parameters in reservoir models can be extremely large, calculation of the inverse can be a problem. In this paper, I discuss four methods of calculating the inverse of the covariance, two of which are analytical, and two of which are purely numerical. By taking advantage of the assumed stationarity of the covariance, none of the methods require inversion of the full covariance matrix.     

Hydrocarbon Generating Potential of Mineral—Bituminous Matrix in Source Rocks

Mineral-bituminous matrix(MBM) makes up a major part of source rocks,but its potential in hydrocarbon generation is uncertain,Mineral and organic (Maceral and kerogen) compositions,organic maturity and fluorescence of MBM are studied based on source rock samples from eastern Jiuquan(Jiudong)Basin.The results show that MBM is dominated by inorganic minerals and among the small percentage of organic components those of secondary origins are predominant over the primary species.This strongly indicates that the significance of MBM in hydrocarbon generation is limited.     

四川甘孜生康剪切混杂岩带物质组成、变形特征及演化历史

甘孜生康剪切混杂岩带,它初始发育在陆棚与大陆基之间,是“再生”小洋盆关闭、俯冲－碰撞乃至斜冲剪切、左行走滑综合作用的产物。带内由不同岩性,不同层位,不同时代的构造岩块与遭受强烈剪切变形的粉砂岩、板岩“基质”组合而成。宏观上,无层无序,块体内有序,是造山带特有的非史密斯地层体。     

Numerical simulation of ground acceleration spectra and accelerograms for engineering application

A numerical approach to the earthquake ground motion analysis is proposed for regions where no accelerograms are available. Using Haskell matrix techniques, the response spectra of a layered substratum for SV waves were calculated and then multiplied by the spectra corresponding to Brune's type pulses. The ground acceleration spectra were obtained for different angles of pulse incidence at the substratum base. The spectrum shape depends upon the substratum response and the pulse shape, while its level was related to the maximum ground acceleration corresponding to the expected maximum intensity. Transformation of the ground spectra into the time domain produced numerical accelerograms for horizontal and vertical components and for different angles of pulse incidence. Finally, a standard statistical procedure was applied to obtain the design response spectra used in engineering applications.     

Experimental and computational validation and verification of the Stokes–Darcy and continuum pipe flow models for karst aquifers with dual porosity structure

In our previous study, we developed the Stokes–Darcy (SD) model was developed for flow in a karst aquifer with a conduit bedded in matrix, and the Beavers–Joseph (BJ) condition was used to describe the matrix–conduit interface. We also studied the mathematical well‐posedness of a coupled continuum pipe flow (CCPF) model as well as convergence rates of its finite element approximation. In this study, to compare the SD model with the CCPF model, we used numerical analyses to validate finite element discretisation methods for the two models. Using computational experiments, simulation codes implementing the finite element discretisations are then verified. Further model validation studies are based on the results of laboratory experiments. Comparing the results of computer simulations and experiments, we concluded that the SD model with the Beavers–Joseph interface condition is a valid model for conduit–matrix systems. On the other hand, the CCPF model with the value of the exchange parameter chosen within the range suggested in the literature perhaps does not result in good agreement with experimental observations. We then examined the sensitivity of the CCPF model with respect to the exchange parameter, concluding that, as has previously been noted, the model is highly sensitive for small values of the exchange parameter. However, for larger values, the model becomes less sensitive and, more important, also produces results that are in better agreement with experimental observations. This suggests that the CCPF model may also produce accurate simulation results, if one chooses larger values of the exchange parameter than those suggested in the literature. Copyright © 2011 John Wiley & Sons, Ltd.     

The effects of rock fragments on hydrologic and hydraulic responses along a slope

A model describing the three‐dimensional matrix flow along a slope with rock fragments or impermeable blocks was developed. The model was combined with modified Picard's iteration to ensure mass conservation in the unsaturated flow. We found that rock fragments obstruct water flow along the slope. The groundwater table must be raised to provide a sufficient pore water pressure gradient to facilitate water flow, but higher pore water pressure may induce slope failure. We also conducted a bench‐scale laboratory flume experiment to examine the effects of impermeable blocks on downstream seepage flow. In addition, a numerical experiment was conducted to examine how different arrangements of impermeable blocks affect downstream seepage flow and pore water pressure. This research demonstrated that the hydraulic phenomena were affected when impermeable blocks were present, and pore water pressure increased as the position of impermeable blocks was lowered. Copyright © 2006 John Wiley & Sons, Ltd.     

黄河流域湿地景观时空演变格局分析

湿地景观的时空演变及其驱动因素研究是湿地生态恢复与保护的重要参考,本文利用1980—2015年7期黄河流域土地利用数据构建黄河流域湿地矢量数据集,基于景观格局指数对黄河流域湿地的时空演变特征进行定量和定性分析;采用转移矩阵对每两个时期湿地资源的转移类型和数量进行计算与分析。研究结果表明,①1980—2015年,黄河流域湿地率为3.5%,其中自然湿地率约为2.0%,即黄河流域的湿地类型以自然湿地为主。②斑块面积结果显示,黄河流域湿地总面积减少了312.74km²,表现为人工湿地增加,自然湿地减少;自然湿地中沼泽湿地呈增加状态,主要是在2005—2010年增加了979.22km²,滩地呈减少状态,减少了1218.19km²,主要发生在1990—1995年和2005—2010年。斑块密度结果显示,随着河渠和滩地受人为活动影响程度的加大,两者的斑块破碎化程度逐渐加大。最大斑块指数结果显示,水田是黄河流域的主导湿地类型,沼泽和湖泊是自然湿地中的主导湿地类型。③黄河流域湿地类型与非湿地之间转换是黄河流域景观转换的主要组成部分,其中沼泽与滩地是面积发生变化的主要湿地类型。