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61.
本文给出了1989 年8 月17 日耀斑后环的观测视向速度场,在环内物质在太阳重力、磁场梯度和大气压力梯度联合作用下沿环腿螺旋上升和环内物质密度由环腿向环顶和环足线性递增的假设下,理论上计算了该环系的视向速度场,理论计算和观测结果基本相符,似乎为耀斑物质由色球蒸发作上升运动的观点提供了间接的例证  相似文献   
62.
Development and testing of a serially multiplexed fiber optic sensor system is described. The sensor differs from conventional fiber optic acoustic systems, as it is capable of sensing AE emissions at several points along the length of a single fiber. Multiplexing provides for single channel detection of cracks and their locations in large structural systems. An algorithm was developed for signal recognition and tagging of the AE waveforms for detection of crack locations. Laboratory experiments on plain concrete beams and post-tensioned FRP tendons were performed to evaluate the crack detection capability of the sensor system. The acoustic emission sensor was able to detect initiation, growth and location of the cracks in concrete as well as in the FRP tendons. The AE system is potentially suitable for applications involving health monitoring of structures following an earthquake Supported by: National Science Foundation, Grant number CMS-9900338  相似文献   
63.
裴荣富 《地球科学》2002,27(1):72-80
“后工业”(post-industry)是知识经济或曰“新经济”的发展时代。这个时代的自然资源和一般劳动力资源,包括矿产资源在国民经济和社会发展中的基础地位逐渐为知识产权、市场网络、信息、创新环境等后天获得性资源,以及为创新人才的新“认知”(recognized intellect,RI)所代替。然而,据矿产资源分布及其成矿既具有一定的全球统一性又有区域的特殊性,以及不同国家(地区)对矿产资源勘查程度的不均衡性,特别是矿业活动与其他产业性质的不同,如何能按不同国家(地区)的具体发展状况,做好21世纪矿业向“后工业”发展势态的倾斜,达到适者生存和矿业可持续发展的目标是当代探讨的重大问题。在概括阐述了21世纪矿业发展势态、矿业活动特点及其自然属性的基础上,提出了矿业可持续发展的地质勘查和矿业活动决策支持系统的模拟,以及对当前紧缺铜矿资源可持续发展的新“认知”。  相似文献   
64.
东亚大陆边缘的构造格架及其中-新生代演化   总被引:10,自引:0,他引:10  
燕山运动在亚洲大陆雏形东缘形成2条北东向的剪切带:郯庐断裂带和长乐-南澳-中央构造线断裂带,晚侏罗世—古近纪早期沿之发生地体/地块的拼贴。系统叙述了各移置地体/地块的主要岩石记录和拼贴时代,据起源分为3类:异地的(包括源自冈瓦纳的和源自盘古大洋的)、半异地的和准原地的;据拼贴位置分为2组:拼贴后基本位于原地的(日本海张开以前) 和发生过向北东错移的。新生代内东亚大陆边缘发生解体,可以台湾岛以北的菲律宾海盆断裂为界将东亚大陆边缘弧分为2段,北段仍处于剪切-拉张中,南段已进入剪切挤压-造山阶段。强调该地区中—新生代演化经历了2个里丁旋回, 形成早白垩世的北东向和新近纪的北东东向2期新生构造。  相似文献   
65.
根据铜厂铜矿床辉钼矿ReOs同位素模式年龄和黄铜矿RbSr同位素等时线年龄分别为889Ma和359Ma,并依据其地质特征和与铜厂岩体之间时空关系,认为早期铜矿化发生在889Ma左右,与铜厂岩体岩浆期后热液有关;晚期铜矿化则发生在359Ma左右,是伴随区域动力变质作用发生的;其矿质来源研究表明既有来自围岩的,又有来自岩体本身的;包裹体测温资料表明成矿温度集中在两个区间:高温大于300℃,低温150~200℃。该矿床为多期、复源、多种成矿作用叠加复合的产物。  相似文献   
66.
Caldear Volcanic Group (CVG), a stratigraphically well defined, calc-alkaline rock complex within Sa de Gata in the eastern part of the Alpine Betic mountain chain, S Spain, consists of three distinct formations: Hernández pyroxene andesites, Bujo hornblende-bearing pyroxene andesites and Viuda hornblende-bearing pyroxene dacites–rhyolites. The letter rock formation may have developed through crystal fractionation of mainly plagioclase and pyroxenes, however there is no direct relation between two formations. CVG has a domainal structure with a northeastern domain where Hernández formation is overlain by Bujo formation while Viuda formation is absent, and a southwestern domain where Viuda formation forms the only fractionate after Hernández formation. Hernández parent magma is thought generated through crustal anatexis by dehydration melting of a predominantly amphibolitic source rock complex which was formed by metamorphism from c. 500 Ma volcano-sedimentary parent material. The domainal structure of CVG is explained by compositional variation within this protogenetic complex. Single crystal U–Pb ages of c. 500 Ma to 1800 Ma for inherited zircon support the presence of clastic material of Proterozoic derivation within the original volcano-sedimentary complex. Regional study of syn-collisional rock formations (Alpine nappe complexes) indicate that the collisional tectonic stage in the Betic-Rif orogenic belt took place rather early (25–30 Ma?) and was followed by a stage of rapid regional rock uplift, fast cooling (c. 500°C/my) and extensional tectonics in the period 22–17 Ma. This later tectonic stage was set into motion by slab break-off which set the stage for a high temperature regime in the overlying lithosphere, providing the framework for the crustal melting and magma production responsible for the calc-alkaline rocks of Alborán volcanic province. Miocene zircon with ages ranging from c. 17 to 11 Ma indicate a rather protracted magmatic development prior to eruption at c. 11 Ma. Post-collisional character of Caldear Volcanic Group thus seems well established.  相似文献   
67.
The Tioueine pluton intrudes the Neoproterozoic series of the Iskel terrane, located in the Tuareg shield, western Hoggar. The consistency of the internal structures as well as the nature and organization of the associated microstructures demonstrate that the Tioueine pluton was emplaced syn-kinematically while N–S strike–slip shear zones were active. The syn-tectonic emplacement of the Tioueine massif implies that this pluton, although belatedly crystallized, entirely belongs to the concept of post-collisional magmatism. In order to date precisely the late Pan-African tectono-metamorphic event in the studied area, an U–Pb age of 523±1 Ma was obtained from abraded zircons of a late quartz–syenite from the Tioueine pluton. This early Cambrian age is younger than the other plutons of the Tuareg shield, which were mainly emplaced between 630 Ma and 580 Ma. This dating also shows that the Tuareg shield was not a single coherent block at 525 Ma, but rather an amalgam of active terranes moving each other along major shear zones. Finally, the Tioueine massif represents probably the final welding of the Tuareg shield assembly of terranes and consequently the end of the post-collisional orogenic episode in the whole Pan-African belt.  相似文献   
68.
后压浆方案的技术可行性论证   总被引:2,自引:1,他引:1       下载免费PDF全文
从地层选择、效果预测、经济分析和施工应用4个方面对钻孔灌注桩后压浆方案进行可行性论证,并对承载力增幅进行了分析。  相似文献   
69.
Gas emission prediction and recovery in underground coal mines   总被引:2,自引:0,他引:2  
Strata gas can be released and captured from non-active and active gas resources either from virgin or relaxed strata, both prior to and when mining activities take place. The high and irregular gas emissions associated with high production longwall mining have provided a need to optimise the methods used to predict these gas levels and the ventilation requirements for gas dilution. A forecast of gas emissions during development drivage and longwall mining indicated possible gas and ventilation problems requiring the introduction of various gas drainage techniques and in maintaining the necessary air quantities in ventilation systems to satisfy the statutory gas limitations for various coal production rates. Although there are sound principles used in world-recognised methods of gas emission prediction, a new approach developed from long-term practical experience in underground gassy coal mine practices and gas-rock mechanics studies appear most suitable for local conditions and mining systems in use. The Lunagas ‘Floorgas' and ‘Roofgas' geomechanical and gas emission models offer an effective solution to these problems. Both programs are the most advanced engineering, numerical tools available to calculate gas source contributions to total gassiness and improve the accuracy and quality of gas control, gas capture technologies and ventilation system design.  相似文献   
70.
赣东北地区构造演化的新认识   总被引:3,自引:0,他引:3  
根据近几年来赣东北地区的区域地质调查及科研工作所获的地质资料、化石资料和实测数据,论述了该区晋宁期以来的构造演化,提出了以下看法:①该区是一个多期造山作用的复合体,它经历了褶皱基底形成、洋陆转化和陆内发展三大阶段和晋宁期、加里东期、印支期、燕山期四个构造旋回;②早古生代该区存在一小洋盆;③加里东期构造旋回在赣东北地区是明显的,其造山作用是存在的,并由此奠定了该区构造分区的总体格局。  相似文献   
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