广西田阳-那坡县堆积铝土矿分布规律初探     

彭志永  赵子宁 《南方国土资源》2002,15(3):37-40

文章试图通过古地理环境、地质构造条件、沉积铝土矿及矿区地貌等因素去初步探讨田阳县-那坡县一带堆积铝土矿优质矿石及含矿率分布的规律性.认为沉积铝土矿及地貌因素是控制该地区堆积铝土矿优质矿石及含矿率分布的主要因素.  相似文献   

重庆地面最高气温与最大风速年极值的渐近分布   总被引：3，自引：0，他引：3  

孟庆珍  王增武  冯新  梁秋枫 《成都信息工程学院学报》2004,19(3):436-441

利用重庆1951-1990年间地面最高气温和1956-1990年间地面最大风速年极值的记录,采用韦伯分布和耿贝尔分布分别对其渐近分布进行拟合.通过统计推断,找出重庆地面最高气温和地面最大风速年极值遵循的最佳渐近分布--韦伯分布.  相似文献   

长江中下游地区地下水卤素元素的形成及其分布规律     

曾昭华 《浙江国土资源》1997,(1)

本文以丰富的实际资料，论证了地下水的卤素元素（F、Cl、Br、I）的形成、含量及其分布规律与含水介质成分、上覆岩土性质、地下水退流条件、氧化还原环境、地下水矿化度之间的关系。根据江汉平原东部区和鄱阳湖区地下水中Br、I元素的调查研究结果及它们形成的控制因素与分布规律，结合长江三角洲南部区水文地球化学环境条件分析对比，指出该区是一个形成Br、I矿泉水的有利地区。  相似文献   

冰碛扇型砂金矿床特征及其成矿初探     

杨文智 《河南国土资源》1997,(2)

成生于冰碛扇内，经一定的生物、物理、化学成矿作用，以砂金形态分布而富集成矿的金矿称为冰碛扇型砂金矿床。它具有沿造山带一定标高范围成群、成带分布，沉积物为近源且半胶结，砂金呈面状分布，并以粒金、块金为主，具胶状、浑圆状、包块状构造形态，分布极不均匀等特征。冰碛扇型砂金矿床的成矿作用与河成砂金矿床有本质的区别。它的成矿作用模式是：造山带下地壳富含的活化金通过新构造运动活化的断裂运移地表，经地下流体和地表流体的迁移聚集到冰碛扇这一封闭稳定的生物、物理、化学障环境中，主要经高效聚金微生物有机胶体成矿作用沉淀、再生加大形成砂金，逐步富集成矿床。而红色磨拉石建造中风化离解的Ｆｅ，Ｍｎ物质对沉淀环境ｐＨ值起着一定的调节作用。冰碛扇型砂金矿床在我国西部造山带内广泛分布，具有一定的工业价值，是砂金矿床中一重要类型，应予以重视  相似文献   

广西泥盆纪四射珊瑚的分布与组合特征     

邝国敦 《南方国土资源》1992,(2)

广西早泥盆世晚期至晚泥盆世的碳酸盐台地区发育有两个不同的四射珊瑚群落,此二群落都有其各具特点的珊瑚组合系列。其中,在开阔台地相区的四射珊瑚可划分为9个组合带,而在台地边缘相区则可划分为8个组合带。在早泥盆世早、中期,因岩相分异不明显,四射珊瑚仅可划分为3个组合带。因此证明,四射珊瑚的发展演化与沉积相演变有密切的关系。  相似文献   

The size distribution of trans-Neptunian bodies     

J.R. Donnison 《Planetary and Space Science》2006,54(3):243-250

The magnitude distribution of the trans-Neptunian bodies composed of the Kuiper Belt Objects (KBOs) and Scattered Disk Objects (SDOs) is determined for absolute magnitudes H?7, using maximum likelihood estimation methods. This is translated into a corresponding size distribution. This gave a differential size index of q=3.966±0.15 for KBOs and q=3.016±0.32 for SDOs. It was found that these two distributions were statistically different. The KBOs were further split into classical KBOs and Plutinos which had indices of q=4.074±0.18 and q=3.301±0.37, respectively. There was no statistical evidence that these are different populations. The classical KBOs were further split and examined for four different semi-major axis ranges and it was found that there was moderate evidence that the entire sample was not well represented by one index. The distribution indices of the SDOs were compared with the distributions of short period comets and found to be similar. It is likely that the scattered disk population is the source of the short period comets.  相似文献   

THERMAL EFFECTS OF BUILDING′S EXTERNAL SURFACES IN CITY——Characteristics of Heat Flux into and out of External Wall Surfaces     

ZHANG Yi-ping  HE Yun-ling    LIU Yu-hong  MA You-xin  LI You-rong  DOU Jun-xia     《中国地理科学(英文版)》2004,(4)

1INTRODUCTIONWiththerecentmodernizationandurbanizationofChi-na,urbanareashavegreatlyincreased, andgiantbuild-ings,especiallythosetallerthan100m,havebeendomi-nantincities,whichhave resultedinthegreatincreaseintheproportionofbuilding'sexternalsurfacetototalurbanarea.Thedifferencesofthermalpropertiesmain-lyinducedbysolarradiationbetweenbuilding'sexter-nalsurfacesareobviousfordifferentexposures,whichcaninevitablyinfluencethedistributionsofairtempera-turenearby,eventheverticaldistributionsofurb…  相似文献   

模糊划分矩阵在岩土参数概率分布中的应用   总被引：1，自引：0，他引：1  

刘明  熊彩霞  马金荣 《地球科学与环境学报》2002,24(4):38-41

讨论如何在小样本条件下用已有的过程经验与试验资料确定岩土参数概率分布,用模糊划分矩阵与BAYES方法相结合,给出由小样本试验数据确定岩土参数的概率分布。  相似文献   

About Darcy's law in non-Galilean frame     

C. Geindreau  E. Sawicki  J.-L. Auriault  P. Royer 《国际地质力学数值与分析法杂志》2004,28(3):229-249

This paper is aimed towards investigating the filtration law of an incompressible viscous Newtonian fluid through a rigid non-inertial porous medium (e.g. a porous medium placed in a centrifuge basket). The filtration law is obtained by upscaling the flow equations at the pore scale. The upscaling technique is the homogenization method of multiple scale expansions which rigorously gives the macroscopic behaviour and the effective properties without any prerequisite on the form of the macroscopic equations. The derived filtration law is similar to Darcy's law, but the tensor of permeability presents the following remarkable properties: it depends upon the angular velocity of the porous matrix, it verifies Hall–Onsager's relationship and it is a non-symmetric tensor. We thus deduce that, under rotation, an isotropic porous medium leads to a non-isotropic effective permeability. In this paper, we present the results of numerical simulations of the flow through rotating porous media. This allows us to highlight the deviations of the flow due to Coriolis effects at both the microscopic scale (i.e. the pore scale), and the macroscopic scale (i.e. the sample scale). The above results confirm that for an isotropic medium, phenomenological laws already proposed in the literature fails at reproducing three-dimensional Coriolis effects in all types of pores geometry. We show that Coriolis effects may lead to significant variations of the permeability measured during centrifuge tests when the inverse Ekman number Ek⁻¹ is 𝒪(1). These variations are estimated to be less than 5% if Ek⁻¹<0.2, which is the case of classical geotechnical centrifuge tests. We finally conclude by showing that available experimental data from tests carried out in centrifuges are not sufficient to determining the effective tensor of permeability of rotating porous media. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

A stepwise method for determining the number of component distributions in a mixture     

Yu-Sheng Hsu  Joseph J. Walker  David E. Ogren 《Mathematical Geology》1986,18(2):153-160

This paper considers the problem of estimatingm, the number of components in a finite mixture of distributions from a parametric family. A step-up procedure using the bootstrap method is proposed. Some properties of the procedure are illustrated with simulation studies. An example of the method, applied to orientation of beach clasts, is given.  相似文献