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1.
为解决大角度起伏地形即陡峭地形(如河流阶地、冲沟、堤坝、山谷、山脊等)对实测视电阻率的影响问题,这里优化了三维有限元数值模拟中的单元积分形式,使之适合大倾角地形条件下对电阻率的数值模拟.为验证方法的正确性,采用保角变换计算了相近地形在均匀电流场情况下,陡峭地形引起的视电阻率变化特征.计算表明,对于缓倾斜地形,有限元数值... 相似文献
2.
复杂地形条件下激发极化有限单元法三维数值模拟 总被引：2，自引：1，他引：1
野外激电勘查过程中,据激电异常进行钻探验证时,常发生验证目标矿体擦边而过现象.究其原因是在实际勘查中,地形的起伏变化改变了地下电场的分布规律,导致激电异常发生位移及幅值改变.为了改善、克服这种现象,必须从理论上进行研究.运用四面体单元三维有限单元数值正演计算方法对此进行了理论研究,选用典型山谷地形水平层状极化体模型进行数值模拟计算.研究结果表明:①起伏地形不产生假的激电异常,仅对激电异常的形态和幅值产生影响;②采用四面体剖分单元有限单元法研究复杂地形条件对激电异常的影响是行之有效的. 相似文献
3.
高密度电阻率法地形影响校正 总被引：1，自引：0，他引：1
采用有限元法实现高密度电阻率法二维模型的正演模拟,将一定地形条件下的二维地电模型的视电阻率响应,分解为畸变场和正常场二部分进行分析.采用比值法消除由地形引起的畸变场,从而获得水平地形条件下二维地电结构的视电阻率值.在实际资料的校正中,取得了较好的应用效果. 相似文献
4.
全空间中空腔同壁点电源场电位的边界元算法及其应用 总被引：1，自引：0，他引：1
本应用边界元数值计算法对全空间中空隙内壁点电源场的电位求解。并将其有效地应用于井下电阻率法三维模拟计算中，从理论上给出了巷道电阻率法中正常背影场与异常场的某些基本规律以及实际资料解释中所需注意的问题。 相似文献
5.
水下直流电阻率法数值模拟 总被引：5，自引：0，他引：5
利用有限单元法对水下电阻率测深进行数值模拟。与地面测量不同的是，水下电极所处的深度、水体本身和水底地形都会给电阻率数据造成较大影响，给数据的解释带来困难。若先通过计算，分析不同电阻率装置在水下测量时的视电阻率与水深的关系，再用有限单元法对水下的三维地电断面进行数值模拟，讨论水底地形对视电阻率的影响．即可用比较法消除地形影响。 相似文献
6.
复杂地形下高密度激电法2.5维有限单元法数值模拟 总被引：1，自引：0，他引：1
目前三维有限元模拟计算量大,计算效率低,对计算机要求较高,2.5维模拟是三维问题的简化,较好地克服了上述问题。在高密度激电法模拟中,模拟的点数一般较大,要求程序计算效率高,因此对高密度激电法2.5维模拟研究是必要的。首先给出了2.5维稳定电流场的边值问题及对应的变分问题;为了能更好模拟复杂地形对极化率异常的影响,采用三角形网格,有利于模拟复杂地形又有利于将其应用于反演计算。推导了基于连续电性介质的2.5维稳定电流场的有限元法,利用等效电阻率法,编制了2.5维高密度激电法有限元模拟程序,计算了水平地形及起伏地形下的极化率异常模型,并验证了方法的可行性,分析得出了山谷地形比山脊地形对极化率观测的影响大的结果。 相似文献
7.
全空间中空腔内壁点电源场电位的边界元算法及其应用 总被引：2，自引：0，他引：2
本文应用边界元数值计算法对全空间中空腔内壁点电源场的电位求解。并将其有效地应用于井下电阻率法三维模拟计算中，从理论上给出了巷道电阻率法中正常背景场与异常场的某些基本规律以及实际资料解释中所需注意的问题。 相似文献
8.
复杂地形条件下频率测深资料解释 总被引：1，自引：0，他引：1
采用比值法对视电阻率数据进行处理,沿电磁波传播方向作视电阻率比值断面等值线图的方法来消除起伏地形的影响,进行定性和半定量解释.阐述了确定电磁波传播方向的两种方法,即采用二维涡流有限元方程计算断面电磁场强度分布的方法和采用导电纸模拟实验测定稳定电流场中等位线的近似方法.并在贵州某地试验剖面上实际应用该方法进行解释,证明了方法的有效性. 相似文献
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10.
大地电磁测控深二维地形影响及其校正方法研究 总被引：4，自引：0，他引：4
采用有限元法实现ＭＴ二维模型的正演模拟,将地形条件下的二维地电模型的ＭＴ响应分解为地形引起的畸变场和与测点高程位置有关的稳定场两部进行分析。用有限元法模拟二维地形条件下地电结构的ＭＴ响应和地形的ＭＴ响应,采用幽会法消除地形引起的干扰场,然后,将消除地形影响后的视电阻率值通过延拓方法获水平地形条件下二维地电结构的视电阻率分布,完善在地电磁测深视电阻率的地形校正。 相似文献
11.
Inter-regional correlation of transgressions and regressions in the Cretaceous period 总被引：1，自引：0，他引：1
T. Matsumoto 《Cretaceous Research》1980,1(4):359-373
Well investigated platforms have been selected in each continent, and the history of Cretaceous transgressions and regressions there is concisely reviewed from the available evidence. The factual records have been summarized into a diagram and the timing of the events correlated between distant as well as adjoining areas.On a global scale, major transgressions were stepwise enlarged in space and time from the Neocomian, via Aptian-Albian, to the Late Cretaceous, and the post-Cretaceous regression was very remarkable. Minor cycles of transgression-regression were not always synchronous between different areas. Some of them were, however, nearly synchronous between the areas facing the same ocean.Tectono-eustasy may have been the main cause of the phenomena of transgression-regression, but certain kinds of other tectonic movements which affected even the so-called stable platforms were also responsible for the phenomena. The combined effects of various causes may have been unusual in the Cretaceous, since it was a period of global tectonic activity. The slowing down of this activity followed by readjustments may have been the cause of the global regression at the end of the Cretaceous. 相似文献
12.
The Afyon stratovolcano exhibits lamprophyric rocks, emplaced as hydrovolcanic products, aphanitic lava flows and dyke intrusions, during the final stages of volcanic activity. Most of the Afyon volcanics belong to the silica-saturated alkaline suite, as potassic trachyandesites and trachytes, while the products of the latest activity are lamproitic lamprophyres (jumillite, orendite, verite, fitztroyite) and alkaline lamprophyres (campto-sannaite, sannaite, hyalo-monchiquite, analcime–monchiquite). Afyon lamprophyres exhibit LILE and Zr enrichments, related to mantle metasomatism. 相似文献
13.
K.Naganjaneyulu 《地学前缘(英文版)》2014,5(1):1-2
正The Precambrian shields and associated suture zones of the globe preserve important records of continental growth and destruction,the formation and closure of ocean basins,and the early evolution of the Earth in terms of tectonics,resources,and environment.They also offer critical clues on the nature and style 相似文献
14.
Daniel Harlov 《地学前缘(英文版)》2014,5(5):621-625
正1.Introduction This special issue of Geoscience Frontiers is a tribute volume honoring the life and career of Jacques Touret.A set of research papers has been assembled,which broadly reflect his research interests over his 50 plus year career.These papers focus on the role that fluids play during the formation and evolution of the Earth's crust.Below I provide a brief summary of the life of Jacques Touret,along with a select bibliography of his more important papers.This is then followed by a brief introduction to the papers assembled for this special issue. 相似文献
15.
《地学前缘(英文版)》2014,(1):139-141
正1 AIM AND SCOPE GEOSCIENCE FRONTIERS(GSF)is a bi-monthly international journal that publishes in English high quality original research articles and timely reviews in interdisciplinary fields of Earth and Planetary Sciences.GSF aims to bridge innovative,provocative and challenging concepts and models related to various fields of research including petrology and geochemistry in understanding lithospheric architecture and mantle dynamics,global tectonics,economic geology and fuel exploration,geophysics,stratigraphy and paleontology with new 相似文献
16.
正The world petroleum exploration suggests that,about70%of the world’s potash resources were discovered during oil and gas exploration(Zheng et al.,2007).The Kuqa depression in the Tarim basin is abundant with petroleum exploration data,and 相似文献
17.
正Qarhan Salt Lake is located in the eastern part of the Qaidam Basin,which is first discovered the large potash deposit in the late 1950s.The Bieletan section is located in the west of Qarhan Salt Lake,where saline sediment 相似文献
18.
正With the approach of the 45th World Earth Day,China’s Ministry of Land and Resources issued the status of the Chinese geological survey and environments on 22nd April 2013.Regional geological survey in 2013 achieved new results—(why was oceanic in twice?)polar and oceanic expedition were fully completed,a national census of geography was begun,and 相似文献
19.
正1 Introduction The Lop Nor playa,located in the eastern end of the Tarim Basin,capped with a thick salt crust covering an area of approximately 5,500 km2(Ma 2007)that closely resembles a"Great Ear"in satellite images.Understanding the formation of the salt crust can provide important 相似文献
20.
In Liaoning, Hunan, Guangxi, Guizhou, Gansu, Sichuan, Anhui, Jilin and other provinces in China, there is a wide occurrence of metal quantity over 1000 tons of refractory gold ores, principally because of low gold recoveries and become ＂stay mine＂. Features of refi＇actory gold ores are： gold in micro-particles or a microscopic state that is wrapped in pyrite, presence of arsenopyrite and other sulfide minerals or disseminated in the crystal lattice of sulfide minerals; harmful impurity elements such as arsenic, carbon, mercury, antimony, copper with high content are closely related with the gold, and these elements affect the contact reaction between the gold and solvent extraction, making the recovery of the gold extraction process low. In the past 20 years, overseas countries have developed the application of the roasting oxidation method, hot acid （alkali） oxidation, bacterial oxidation and flash chlorination oxidation technology to solve this problem.Among these, biological oxidation has developed rapidly in the domestic market and gold enterprises abroad because of its low investment in infrastructure, low production costs, less environmental pollution, simple process and easy control, etc. 相似文献