共查询到20条相似文献，搜索用时 31 毫秒
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Deng Jun Faculty of Geology Mineral Resources China University of Geosciences Beijing Fang Yun Faculty of Engineering China University of Geosciences Wuhan Wan Li Foundation Department South China Construction University 《中国地质大学学报(英文版)》2000,11(2)
The forecasting of concealed ore deposits,a new puzzlein econom ic geology,is a major academic discipline crucial forthe development of geosciences in the2 1st century(NationalResearch Council,1993) . In recent years,many geoscientistsinside and outside China have studied and discussed theoriesand m ethods of concealed ore deposit forecast from differentaspects,and they have obtained many achievements(Xu andCai,2 0 0 0 ) . However,the open nature,the non- balancedstate,and the non- reversibl… 相似文献
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无定形态游离氧化铁以其自身的特性及其脱水老化作用,对粘性土的物理性质、水理性质乃至工程性质产生了一定程度的影响。本文就粘性土的物理性质、水理性质及力学性质在无定形态游离氧化铁脱水过程中的变化进行了初步研究,期望对粘性土的土工测试方法及参数的合理测定有所裨益。 相似文献
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造山带地球化学研究的理论构想与实践 总被引：9，自引：0，他引：9
简要地评述了现今造山带地球化学研究的状况,为适应造山带研究与大陆动力学接轨的需要,讨论了提出了对大陆造山带开展系统性地球化学研究的理论构想及在造山带多学科研究中发挥地球化学专长和优势的技术路线。并以近５年秦岭造山带研究的主要成果为例,说明实践的效果。 相似文献
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谦比希铜矿床产于中南部非洲赞比亚-刚果(金)铜钴成矿带内,为该成矿带内一典型的铜矿床。为了建立该类矿床的找矿标志并寻找该类矿床,本文从区域地层、区域构造、矿床地质特征和矿床成因等方面着手,对赞比亚谦比希铜矿床勘探地质资料进行综合研究,并与国内同类型大型-超大型矿床在矿床建造、后期改造、矿床成因等方面进行对比研究。提出了该类型矿床在成矿时-空分布、容矿岩石、控矿构造、成矿条件、矿床的后期改造方面的问题讨论。 相似文献
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在岩体工程的稳定分析中时间常常是一项不可忽视的因素.但是目前进行的许多非线性分析工作一般说来仅考虑了岩体、节理等应力一应变关系的力学非线性性质和强度特性,对于时间因素很少顾及.特别是根据实测的节理面、软弱夹层等的流变性质进行相应的分析的例子还很少. 相似文献
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As additional multiple-point statistical (MPS) algorithms are developed, there is an increased need for scientific ways for comparison beyond the usual visual comparison or simple metrics, such as connectivity measures. In this paper, we start from the general observation that any (not just MPS) geostatistical simulation algorithm represents two types of variability: (1) the within-realization variability, namely, that realizations reproduce a spatial continuity model (variogram, Boolean, or training-image based), (2) the between-realization variability representing a model of spatial uncertainty. In this paper, it is argued that any comparison of algorithms needs, at a minimum, to be based on these two randomizations. In fact, for certain MPS algorithms, it is illustrated with different examples that there is often a trade-off: Increased pattern reproduction entails reduced spatial uncertainty. In this paper, the subjective choice that the best algorithm maximizes pattern reproduction is made while at the same time maximizes spatial uncertainty. The discussion is also limited to fairly standard multiple-point algorithms and that our method does not necessarily apply to more recent or possibly future developments. In order to render these fundamental principles quantitative, this paper relies on a distance-based measure for both within-realization variability (pattern reproduction) and between-realization variability (spatial uncertainty). It is illustrated in this paper that this method is efficient and effective for two-dimensional, three-dimensional, continuous, and discrete training images. 相似文献
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Najla Frih Vincent Martin Jean Elizabeth Roberts Ali Saada 《Computational Geosciences》2012,16(4):1043-1060
We consider a model for fluid flow in a porous medium with a fracture. In this model, the fracture is treated as an interface between subdomains, on which specific equations have to be solved. In this article, we analyze the discrete problem, assuming that the fracture mesh and the subdomain meshes are completely independent, but that the geometry of the fracture is respected. We show that despite this nonconformity, first-order convergence is preserved with the lowest-order Raviart–Thomas(-Nedelec) mixed finite elements. Numerical simulations confirm this result. 相似文献
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J.G. Hudson 《Geology Today》2009,25(3):108-111
In December of 2004 a dinosaur footprint was discovered near Scarborough on the North Yorkshire coast of northern England. Arguably, it was the largest and best-preserved theropod print yet discovered on this coast, and indicated for the first time that large carnivores were present in the area around 165 million years ago. Many trace fossils are enigmatic ghosts of the animal that formed them, but footprints are so much more tangible; a footprint preserved from Jurassic time represents an individual animal, walking in this place at this time. In this article I provide the background to the discovery and collection of this trace fossil, which has enabled this footprint in time to be preserved for future study. 相似文献
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In this paper ,a practical approach to rheological behavior of joints and weak intercalations in rock mass is given .In finite element analysis with this method for a rock engineering problem ,good agreement is found in a comparison of the calculated results with the deformations measured . 相似文献
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CSAMT的静校正应用——联合反演法 总被引：2，自引：0，他引：2
CSAMT方法应用在地下近地表存在电性横向不均匀体时,在双对数坐标系中视电阻率曲线会出现沿着视电阻率轴平行移动的现象,称之为静态效应。静态效应对深部电性结构处理解释结果影响重大,需对其进行合适的校正。笔者介绍了目前通常使用的几种静态校正方法,并且分析了各方法的优缺点。对比各种方法,我们选择了时间域的瞬变电磁法和频率域的可控源电磁测深做联合反演,用精度较高的瞬变电磁数据校正受静态影响的可控源测深数据。在甘肃某地进行的铅锌矿CSAMT勘探中,应用联合反演法对可控源测深做静态校正,处理结果与实际地质情况吻合较好。 相似文献
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The neural network system has been developing very fast recently. It has been widely used in many industries such as automation, nuclear power plant, chemical industry, etc. Neural network systems have a great advantage in dealing with problems in which many factors influence the process and result, and the understanding of this process is poor, and there are experimental data or field data. In rock engineering, many problems are of this nature. In this paper, a brief introduction to neural network systems is given. Problems such as what is a neural network, how it works and what kind of advantages it has are discussed. After this, several applications in rock engineering, made by us, are presented. Case 1 is ore boundary delineation. In this case, the rock are divided into three classes, i.e.: (1) waste rock; (2) semi-ore; and (3) ore for mining purposes. The neural network system built can judge whether it is ore, semi-ore or waste rock along the borehole according its corresponding geophysical logging data, such as gamma-ray, gamma-gamma, neutron and resistivity. Case 2 is aggregate quality prediction. In this case, the quality parameters: (1) impact value; (2) abrasion value I; and (3) abrasion value II are predicted by using a neural network system based on density, point load, content of quarts and content of brittle minerals. Case 3 is rock indentation depth prediction. In this case, the rock indentation depth under indentation load is predicted by the established neural network system based on the indentation load on rock, indenter type and rock mechanical properties, such as uniaxial compressive strength, Young's modulus. Poisson's ratio, critical energy release rate and density. In all these cases, the neural network systems have been applied successfully. The testing results are satisfactory and better than the existing techniques. 相似文献
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本文对本所研制的BEM-1-D76型钻孔弹模仪的基本原理和各项技术指标、测试方法及现场使用情况作了介绍,并且与国外同类仪器进行了比较,从而表明该仪器是现场测定岩体变形特性的有效新设备。 相似文献
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M. I. Carretero M. Pozo F. Ruiz J. Rodríguez Vidal L. M. Cáceres M. Abad J. M. Muñoz F. Gómez J. M. Campos M. L. González-Regalado M. Olías 《Environmental Earth Sciences》2011,64(5):1215-1223
The multidisciplinary analysis of core sediments from Doñana National Park, south Spain, permits to delimitate both the paleoenvironmental changes and the geochemical evolution of this area during the Holocene. In a first phase (10–6.5 kyr cal), this area was occupied by freshwater/brackish marshes with periodical alternation of dry periods and humid intervals. In a second phase, these marshes were inundated during the Flandrian transgression (~6.5 kyr cal), with the deposition of bioclastic sands. The third phase (6.5–3.6 kyr cal) is characterized by the transition to an old lagoon, with unpolluted, bottom sediments. The geochemical concentrations of these clayey sediments can be used as a geochemical background for present-day and future environmental evaluations of this area. In the following 600 years approximately, two tsunamis caused the partial infilling of this area with bioclastic, marine sediments. In the interval comprised between these two tsunamis, this lagoon was polluted with heavy metals derived from historical mining activities. This environmental contamination represents one of the oldest evidences of mining pollution in the world (>3 kyr cal BP). 相似文献
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光学遥感影像的山地冰川运动速度分析方法 总被引：6，自引：5，他引：1
山地冰川随着地形、气候变化等因素不断运动,及时准确的获取冰川运动速度是研究山地冰川特性以及冰川灾害预警的重要组成部分.将光学影像相关技术应用于冰川的运动监测,并在运算中提出了"移动格网"方法.选用相同区域时间序列影像,一幅影像上用格网分割冰川区域,每个小单元格在另一幅影像上根据冰川表面纹理特征进行相关分析,取相关性最大的对应单元格作为变化后的位置,两幅图像由单元格位移量计算运动速度.影像上格网逐步移动,直至完成整个冰川区域的速度解算.选用天山区域一块冰川间隔10a的光学影像,对方法进行了验证. 相似文献