基于路径的地图目标拓扑关系表达方法     

刘荣  毛建华  熊助国  吕开云 《华东地质学院学报》2002,25(4):329-332

在分析图论路径性质的基础上，利用路径之间的拓扑关系，分析了地图中点、线、面目标之间的拓扑关系，并分析了这种表达方法相对于其它的表达方法的优点。  相似文献   

拱形洞室围岩内岩爆的计算机模拟与控制方法          下载免费PDF全文

何思为  卢世杰  向贤礼 《探矿工程》2002,(4):55-57

借用GDA软件来模拟开挖周边的应力重分布，在此基础上，重点分析了拱形洞室的拱顶、拱肩、两侧及底角的应力分布与岩爆的关系。并提出如何依据dσ3/（σ1-σ3）大小与正负来分析和估计岩爆位置，因为应力差σ1-σ3可表征岩石的变形与静态破坏，而最小主应力增量dσ3的大不可表征抵抗这种变形与破坏的能力。结果是拱肩与底角会出现岩爆。分析结果得到了加拿大某矿山的岩爆发生位置实际资料所验证。最后，提出了如何利用预裂爆破方法使岩爆从拱肩迁移到洞室底角。  相似文献   

Attenuation modeling of recent earthquakes in Turkey   总被引：1，自引：0，他引：1  

Polat Gülkan  Erol Kalkan 《Journal of Seismology》2002,6(3):397-409

This paper deals with the derivation of a consistent set of empiricalattenuation relationships for predicting free-field horizontal components ofpeak ground acceleration (PGA) and 5 percent damped pseudoacceleration response spectra (PSA) from 47 strong ground motion recordsrecorded in Turkey. The relationships for Turkey were derived in similarform to those previously developed by Boore et al. (1997) for shallowearthquakes in western North America. The used database was compiledfor earthquakes in Turkey with moment magnitudes (M_w) = 5 thatoccurred between 1976–1999, and consisted of horizontal peak groundacceleration and 5 percent damped response spectra of accelerogramsrecorded on three different site conditions classified as rock, soil and softsoil. The empirical equations for predicting strong ground motion weretypically fit to the strong motion data set by applying nonlinear regressionanalysis according to both random horizontal components and maximumhorizontal components. Comparisons of the results show that groundmotion relations for earthquakes in one region cannot be simply modifiedfor use in engineering analyses in another region. Our results, patternedafter the Boore et al. expressions and dominated by the Kocaeli andDüzce events in 1999, appear to underestimate predictions based ontheir curves for up to about 15 km. For larger distances the reverse holds.  相似文献   

Simulating spatiotemporal variations of atmospheric CO₂ using a nested hemispheric model     

C Geels  J.H Christensen  L.M Frohn  J Brandt 《Physics and Chemistry of the Earth》2002,27(35):1495-1505

A three-dimensional Eulerian nested model for transport, diffusion, and surface fluxes of CO₂ has been developed. The model is used to study the spatial and temporal variations of atmospheric CO₂ concentrations as a step towards a better understanding of the regional source pattern over Europe. The influence from the national surface characteristics, as e.g. fossil CO₂ emissions or ecosystem fluxes, can be treated on a continental or national level in the model. In the future the model can be used as a mean to corroborate national and EU-wide controls or reductions of carbon emissions. One of the major questions in the estimation of e.g. national CO₂ budgets is the quantification of surface ecosystem fluxes. In order to test the sensitivity of atmospheric CO₂ concentrations to ecosystem fluxes, two different parameterizations [J. Geophys. Res. 92 (1987) 2999] and [Global Biogeochem. Cycles 10 (1996) 269] have been implemented in the model. The model both with and without nest is validated by comparison with measurements and the different model results will be discussed. The results show that including a nested domain with higher spatial resolution significantly improves the model performance in some areas. In spite of regional deviations in the two sets of ecosystems fluxes no major differences are seen over Europe as a whole when either of the two parameterizations are included in the model and the results compared.  相似文献   

略论医学地质   总被引：2，自引：1，他引：2  

魏东岩 《化工矿产地质》2003,25(1):41-49

医学地质主要研究地球上的无机物(元素、矿物、岩石等)和有机物(微生物等)对人类、动物和植物的作用和影响。这种作用和影响既包括致病的一面,也包括治病的一面,两者是辩证的统一体。研究表明:砷、汞、氡、石棉、晶质硅等地球物质及沙尘暴等均对人类健康造成危害。而通过对钙、磷等元素与人体骨骼的关系和元素-食物-心血管病关系的分析以及对某些人土食石习惯的探讨都清楚地证明了人体与地球的密切关系。地方病是医学地质研究的重点。我国在地方病防治工作中已取得重要成果。医学地质这一综合性边缘学科有着很大的发展潜力。  相似文献   

Mechanical stratigraphy as a factor controlling the development of a sandbox transfer zone: a three-dimensional analysis   总被引：3，自引：0，他引：3  

Antonio Ravaglia  Claudio Turrini  Silvio Seno 《Journal of Structural Geology》2004,26(12):2269-2283

In thrust belts, fold–fault terminations are common features of the structural architecture and can pose complicated problems to unravel, in particular when two or more terminations are in close proximity. Such terminations usually reflect pre-existing attributes. Amongst the many factors, lateral variations in the mechanical stratigraphy can control along-strike geometry and kinematics of fault-related folds.A displacement transfer zone was produced in a compressional sandbox model by means of two adjacent, mechanically different stratigraphic domains. The experiment allowed two discrete chains to develop in the different domains, so that a complex structural setting occurred in the connecting area. Periclinal folds, oblique thrust fronts and oblique ramps developed in the resulting transfer zone. The interaction between periclines in the transfer zone produced lateral culminations in the folded structures. The analysis of displacement across the structural domains revealed that a significant loss of slip along the faults occurred in the relay zone. In this area, imbricate faulting was partially replaced by layer-parallel shortening. A linear relationship appears to exist between the bed length of the thrust sheet and the related fault slip.  相似文献   

当代美国地理学与可持续发展的理论、实践--基于人地关系论的分析     

税伟  张启春  王山河  冯娴慧 《地理与地理信息科学》2004,20(4):56-60

人地关系论是地理学最基本的理论。可持续发展理论与人地关系论一脉相承，是人地关系论的继承、变革和新发展。该文基于《重新发现地理学》的内容，借助中国地理学者对人地关系论与可持续发展关系的研究成果，以人地关系论来看待有人地关系研究深刻历史基础的美国当代地理学在可持续发展研究中的理论与实践。  相似文献   

邓肯-张模型几种改进方法的比较   总被引：14，自引：3，他引：14  

孔德志  朱俊高 《岩土力学》2004,25(6):971-974

针对邓肯-张模型忽略了中主应力影响的不足之处，不少国内外学者提出了修正方法。在这些方法当中，究竟哪一种方法能更好地反映中主应力的影响，是需要讨论的问题。针对平面应变这一特殊情况，分别运用各种修正方法计算得出其应力．应变关系，在此基础上与平面应变试验资料进行分析比较，从中得出一些有意义的结论。  相似文献   

国家资源环境安全的要素综合评价   总被引：10，自引：0，他引：10  

张雷  刘慧  陈文言 《地球科学进展》2004,19(2):283-288

资源环境安全问题始终是世界各国持续发展的核心任务和基本诉求。考虑到单要素和整体两大分析方法的不足，提出一种针对性很强的要素综合分析方法。根据世界上10个人口超过 1亿以上国家的抽样分析表明，土地、水资源、矿产及生态环境的整体状态是决定国家资源环境安全的基本所在。与此同时，为了改善国家，特别是发展中国家的 资源环境脆弱状态和提高其稳定程度，第一是要严格控制人口增长；第二是努力推进本国资源环境开发的国际化进程；第三是增大智力投入以提高资源深度化加工；第四是加大本国生态环境保护力度。  相似文献   

JUNCTION BETWEEN GANJIANG FAULT AND TANLU FAULT AND ITS SIGNIFICANCE TO MINERALIZATION   总被引：1，自引：0，他引：1  

CUIXuejun XIABin ZENGZuoxun LIULilin CHENXiangyun YANGWeiran 《大地构造与成矿学(英文版)》2005,29(1):1-12

The concept of fault junction is proposed to describe the relationship between the two faults by the authors. The junction relationship between Ganjiang and Tanlu faults is analyzed in this paper, and this has been elucidated through numerical simulation about the tectonic stress field analysis. Numerical simulation of the tectonic stress field conducted for the major mineralization stage of the Jiujiang-Ruichang junction area reveals that the stress Feld of the junction structure at the major mineralization stage shows a relatively close relationship with the formation of the ore deposits (occurrences).  相似文献