试用极轨气象卫星遥感监测土壤墒情   总被引：2，自引：0，他引：2  

赵玉金 《气象》1994,20(4):37-40

讨论了用极轨气象卫星资料监测表层土壤湿度的方法。在建立土壤湿度与卫星遥感资料的关系时，为了消除土壤条件的影响，把全省分为４个区域来研究。考虑了气候条件，植被状况不同的影响，并给出了简单的订正方法，同时也给出了卫星资料的重新地理校正，资料的输出及存储方法等。  相似文献   

新疆北天山地区震磁预报研究     

王瑞琴 《内陆地震》1994,8(3):229-233

采用统一的分析方法和标准从北天山地区的地磁场总强度资料中提取异常信息．结果表明，在区内发生的一些中强地震前，震中周围的台站存在较明显的中、短期异常．  相似文献   

对应分析的原理和数据预处理     

张克权  郭仁忠 《武汉大学学报(信息科学版)》1986,(4)

本文对多元统计分析中目前应用的对应分析方法的原理公式作了重新推导,提出 z_(ij)=(p_(ij)/p_(i.)p_(.j))-1的数据变换公式;并对原始数据作了严格的预处理。最后应用一个实例计算和作图,与简单的因子分析及原用的对应分析成果作了比较。理论和算例都说明本文介绍的对应分析的数据预处理和分析方法较原用方法原理上更正确,应用上更合理,并克服了变量中对各种数据原有的局限性。  相似文献   

硅酸盐类样品中硅、铁、铝、钛、锰、钙、镁、钾、钠和磷的x射线荧光光谱测定     

肖德明  甘璇玑  卜正才 《铀矿地质》1986,(4)

本文拟定了一种以熔融法制备样片,用X射线荧光光谱测定硅酸盐类样品中Si、Fe、Al、Tj、Mn、Ca、Mg、K、Na、P等元素的分析方法。在对不同靶材X光管和分光晶体实验对比的基础上,选择了最佳的测量条件。该法具有快速、准确,测量范围广,检测限低,价格便宜等优点。经过近百个各种类型标样或管理样品的分析对比表明,本法不仅适用于硅酸盐类岩石样品的分析,还适用于铁矿、铝土矿、碳酸盐类岩矿样品以及水泥、耐火材料等样品的分析。  相似文献   

Digital modeling studies for evaluation of hydrogeological characteristics in Shadnagar granite basin,Andhra Pradesh,India     

B. H. Briz-Kishore 《Journal of Earth System Science》1982,91(3):219-234

The use of digital models has increased significantly in recent years with the accessibility of fast computing machines. A variable dimensioned digital model was constructed for the Shadnagar granite basin using SPECTRUM-7 micro computer to integrate various hydrogeological characteristics and for their quantitative evaluation. The basin has an areal extent of 437 sq km and is demarcated with clear water divides in all directions. Transmissivity, recharge and discharge at each cell of the basin area were estimated by trial and error simulation of the hydrogeological phenomenon under steady state condition. Dynamic simulation at representative nodes facilitated the estimation of storage coefficient. The capability of the constructed model was established by the conformance of the simulated hydrographs with the actual behaviour of the ground water system. The entire studies ammended the earlier arrived estimates of various input/output hydrogeological parameters and evolved a methodology for efficient processing of aquifer simulation data  相似文献   

川西地区小震重新定位及其活动构造意义   总被引：59，自引：18，他引：59       下载免费PDF全文

朱艾斓  徐锡伟  周永胜  尹京苑  甘卫军  陈桂华 《地球物理学报》2005,48(3):629-636

使用双差地震定位法对川西地区1992～2002年的13367个小震进行重新定位， 初步分析了地震活动性与地表活动构造的关系及其揭示的构造信息. 重新定位后，地震活动沿活动断裂成线（带）状分布现象非常突出，呈现出与地表活动构造的密切关系：结构简单的单一走滑断层具有上宽下陡的花状结构特征，拉分盆地与逆断裂具有线性而发散的分布式结构特征，逆断裂之下还存在缺震层. 此外，沿活动断裂带地震活动还具有空间分段性，揭示出局部地段存在着隐伏活动断裂和可圈定为地震危险区的地震空区. 震源深度分布显示，川西高原在15～20km的深度范围内普遍存在厚度约5km的缺震层，以高温高压实验结果为基础，通过计算川西地区地壳强度表明，大约14～19km的深度范围花岗岩处于塑性流变状态，说明缺震层的出现具有地壳物质塑性变形基础.  相似文献   

Reliability analysis of drilled shaft behavior using finite difference method and <Emphasis Type="Italic">Monte Carlo</Emphasis> simulation     

Anil Misra  Lance A. Roberts  Steven M. Levorson 《Geotechnical and Geological Engineering》2007,25(1):65-77

Load displacement analysis of drilled shafts can be accomplished by utilizing the “t-z” method, which models soil resistance along the length and tip of the drilled shaft as a series of springs. For non-linear soil springs, the governing differential equation that describes the soil-structure interaction may be discretized into a set of algebraic equations based upon finite difference methods. This system of algebraic equations may be solved to determine the load–displacement behavior of the drilled shaft when subjected to compression or pullout. By combining the finite difference method with Monte Carlo simulation techniques, a probabilistic load–displacement analysis can be conducted. The probabilistic analysis is advantageous compared to standard factor of safety design because uncertainties with the shaft–soil interface and tip properties can be independently quantified. This paper presents a reliability analysis of drilled shaft behavior by combining the finite difference technique for analyzing non-linear load–displacement behavior with Monte Carlo simulation method. As a result we develop probabilistic relationships for drilled shaft design for both total stress (undrained) and effective stress (drained) parameters. The results are presented in the form of factor of safety or resistance factors suitable for serviceability design of drilled shafts.  相似文献   

A method to estimate hydraulic conductivity from bulk geochemical compositions     

Hsueh-Yu Lu 《Environmental Geology》2007,51(6):1029-1041

A new method has been developed to estimate the hydraulic conductivity in unconsolidated aquifers. The method uses bulk geochemical compositions correlated with hydraulic conductivities measured by pumping tests. The concept is based on a general rule that hydraulic conductivity is principally controlled by grain-size distribution and particle shape,both of which relate to mineralogical composition. Using a MINLITH algorithm, normative mineralogical compositions can be derived from bulk geochemical compositions economically and expediently, and then correlated to the hydraulic conductivity determined by pumping tests in the field. In this study, 202 sediment samples from nine unconsolidated aquifers were analyzed by X-ray fluorescence. Although hydraulic conductivity does not show a definite relationship with geochemical compositions, it does demonstrate a linear logarithmic equation to the content of normative earthy minerals. However, linear regressed equations should not be applied to aquifers composed of medium to coarse sand and gravel sizes due to interference from lithic fragments. In addition, this equation tends to overestimate hydraulic conductivity possibly because the effect of compaction is ignored in this study.  相似文献   

原子荧光光谱分析环境样品中砷锑铋汞易出现的问题及解决方法   总被引：2，自引：0，他引：2  

吴海涛 《岩矿测试》2007,26(6):509-510

针对原子荧光光谱法测试砷锑铋汞中易出现的仪器空白不稳定、样品制备及仪器污染等问题，总结出相应的解决方法。  相似文献   

Digital Image Based Approach for Three-Dimensional Mechanical Analysis of Heterogeneous Rocks   总被引：2，自引：0，他引：2  

S. Chen  Z. Q. Yue  L. G. Tham 《Rock Mechanics and Rock Engineering》2007,40(2):145-168

Summary This paper presents a digital image based approach for three-dimensional (3-D) numerical simulation and failure analysis of rocks by taking into account the actual 3-D heterogeneity. Digital image techniques are adopted to extract two-dimensional (2-D) material heterogeneity from material surface images. The 2-D image mesostructures are further extrapolated to 3-D cuboid mesostructures by assuming the material surface as a representation of the inner material heterogeneity within a very small depth. The iterative milling and scanning system is set up to generate the 3-D rock mesostructures. A Hong Kong granite specimen is used as an example to demonstrate the procedure of 3-D mesostructure establishment. The mechanical responses and failure process under the conventional Brazilian tensile test condition are examined through numerical analyses. The stress distribution, crack propagation process and failure model of heterogeneous material cases are simulated with a finite difference software. The numerical results indicate that material heterogeneity plays an important role in determining the failure behavior of rocks under external loading.  相似文献