Fission track evidence for the Mesozoic Cenozoic tectonic uplift of Mt. Bogda, Xinjiang, Northwest China     

沈传波  梅廉夫彭蕾 张士万刘麟  汤济广 《中国地球化学学报》2006,25(2):143-151

1 IntroductionThe Mesozoic-Cenozoic tectonic evolution and ki-netics mechanism of the intracontinental orogen are thekey subjects of continental dynamics (Ma Zongjin andGao Xianglin, 2004) and the key to understanding theregional geological tectonics (Qia…  相似文献   

南海西南部曾母盆地早中新世以来沉降史分析   总被引：2，自引：2，他引：2       下载免费PDF全文

吴庐山 邱 燕解习农  刘晓峰江 涛 《中国地质》2005,32(3):370-377

采用回剥法和局部均衡模式研究曾母盆地早中新世以来的沉降史，并探讨了该盆地构造演化特征。曾母盆地自早中新世以来经历了17．5-11．6Ma、11．6-5．5Ma、5．5-3．0Ma和3．0-0Ma的4次快速沉降作用，其构造演化受控于曾母地块与南沙地块及婆罗洲地块的碰撞和盆地两侧的万安-卢帕尔断裂与廷贾走滑断裂的综合作用，可划分为南北双向挤压（晚始新世-早中新世）、走滑改造（中中新世-晚中新世）和区域沉降（上新世-第四纪）3个演化阶段。  相似文献   

明代军事地理研究概述     

王树连 《测绘科学与工程》2005,25(4):52-57

军事地理是谋兵布防的平台。明代被迫在南北两条战线作战：北部沿长城一线防御少数民族南下；东南沿海抗击倭寇入侵。因此，明代格外重视军事地理的研究，研究成果丰硕，著述很多。概述明代军事地理研究成果，不仅是回顾历史，而是借鉴经验。一些著作中提出的御敌方略至今有参考价值。  相似文献   

Study on effects of damping in laminated rubber bearings on seismic responses for a ⅛ scale isolated test structure     

Bong Yoo  Yang‐Hann Kim 《地震工程与结构动力学》2002,31(10):1777-1792

The effects of damping in various laminated rubber bearings (LRB) on the seismic response of a ?‐scale isolated test structure are investigated by shaking table tests and seismic response analyses. A series of shaking table tests of the structure were performed for a fixed base design and for a base isolation design. Two different types of LRB were used: natural rubber bearings (NRB) and lead rubber bearings (LLRB). Three different designs for the LLRB were tested; each design had a different diameter of lead plug, and thus, different damping values. Artificial time histories of peak ground acceleration 0.4g were used in both the tests and the analyses. In both shaking table tests and analyses, as expected, the acceleration responses of the seismically isolated test structure were considerably reduced. However, the shear displacement at the isolators was increased. To reduce the shear displacement in the isolators, the diameter of the lead plug in the LLRB had to be enlarged to increase isolator damping by more than 24%. This caused the isolator stiffness to increase, and resulted in amplifying the floor acceleration response spectra of the isolated test structure in the higher frequency ranges with a monotonic reduction of isolator shear displacement. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

Nonlinear earthquake response analysis and energy calculation for seismic slit shear wall structures     

蒋欢军  吕西林 《地震工程与工程振动(英文版)》2002,1(2):227-237

Based on the concept of structural passive control, a new type of slit shear wall, with improved seismic performance when compared to an ordinary solid shear wall, was proposed by the authors in 1996. The idea has been verified by a series of pseudo-static and dynamic tests. In this paper a macro numerical model is developed for the wall element and the energy dissipation device. Then, nonlinear time history analysis is carried out for a 10-story slit shear wall model tested on a shaking table. Furthermore, the seismic input energy and the individual energy dissipated by the components are calculated by a method based on Newmark-β assumptions for this shear wall model, and the advantages of this shear wall are further demonstrated by the calculation results from the viewpoint of energy. Finally, according to the seismic damage criterion on the basis of plastic accumulative energy and maximum response, the optimal analysis is carried out to select design parameters for the energy dissipation device.  相似文献   

梅州市名城文化景观的保护与开发研究   总被引：5，自引：1，他引：5  

江金波  司徒尚纪 《热带地理》2002,22(4):335-340

从名城文化内涵出发，着眼于作为客家人文中心和名城文化景观的集中的梅州市区，全面分析了其中丰富多样的文化景观资源的特征及其文化内蕴。揭示了梅州名城文化景观保护与开发过程中的成绩与存在问题。并从文化地理学的视觉，结合旅游开发和城市规划，论证了科学保护与开发梅州名城文化景观的下述对策与途径的必要性与可行性：提升名城办的职能并与相关部门共营名城文化氛围；强化名城轴线与标志性文化景观；抢救与保护“老字号”等一批文化景观景区；适度利用，以积极的开发促其效的保护。  相似文献   

Water wars in the Middle East: a looming threat     

Hussein A. Amery 《The Geographical journal》2002,168(4):313-323

This paper explains how hydropolitical dynamics and spatial variables almost triggered a water war between Israel and Lebanon because the latter was building a pump on the Wazzani Spring, a tributary of the Jordan River. The convergence of a regional drought, history of violent confrontations between the two riparians, distrust, varying development needs and territorial disputes almost culminated in a war between these east Mediterranean neighbours. While most international water disputes in the Middle East will be resolved peacefully, some are likely to trigger violent confrontations threatening political stability in the Middle East in the next few decades.  相似文献   

'Trees, forests and communities': some historiographical approaches to environmental history on Africa     

Karen Brown 《Area》2003,35(4):343-356

Focusing on the contested issue of trees and forests, this paper looks at various ways in which historians have explored environmental change and human agency in Africa. It looks in particular at the colonial period and positions the case of the Cape Colony (South Africa) in a broader historiographical context. Colonial silviculture involved both the appropriation of the natural forests and the creation of exotic plantations. These policies generated a mixture of reactions from African communities and had varying effects on the environment. Colonial science and the projects it gave rise to have since been critiqued, contributing to the promotion of community-based forestry schemes that try to incorporate indigenous knowledge and ideas about land use.  相似文献   

随机地震动模拟的时间序列法及其工程应用   总被引：3，自引：0，他引：3  

胡孔国  陈小兵  岳清瑞 《世界地震工程》2003,19(1):141-153

系统研究了AR和ARMA时间序列方法生成给定加速度功率谱人工地震波的新方法，根据相应理论编制了程序，并生成了人工地震加速时程曲线，然后用生成的人工地震波进行结构动力时程分析，与实际地震波分析的结果进行了对比，计算结果表明，本文用于合成人工地震波的方法是可行的，生成的人工波可以用于实际结构的地震反应分析。  相似文献   

大型双槽渡槽地震反应分析   总被引：3，自引：0，他引：3  

杜晓伟  陈淮  孙国钧  王博 《世界地震工程》2003,19(2):23-26

为了得到比较精确的大型双槽渡槽结构的地震反应，根据渡槽结构复杂、影响动力因素较多等特点，采用8结点空间块体单元对渡槽槽身和槽墩进行有限元离散，分别用耦合自由度和多个弹簧单元分别模拟渡槽槽身横向拉杆、加劲肋和盆式橡胶支座，建立了大型双槽渡槽结构地层反应分析的有限元模型，计算了南水北调水利工程中的双洎河大型双槽渡槽的振动特性，并分别用反应谱法和时程分析法对该渡槽进行了地震反应分析，计算结果可为该渡槽的抗震设计提供参考。  相似文献