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171.
In this paper, an inverse mapping is used to transform the previously-derived analytical solutions from a local elliptical coordinate system into a conventional Cartesian coordinate system. This enables a complete set of exact analytical solutions to be derived rigorously for the pore-fluid velocity, stream function, and excess pore-fluid pressure around and within buried inclined elliptic inclusions in pore-fluid-saturated porous rocks. To maximize the application range of the derived analytical solutions, the focal distance of an ellipse is used to represent the size of the ellipse, while the length ratio of the long axis to the short one is used to represent the geometrical shape of the ellipse. Since the present analytical solutions are expressed in a conventional Cartesian coordinate system, it is convenient to investigate, both qualitatively and quantitatively, the distribution patterns of the pore-fluid flow and excess pressure around and within many different families of buried inclined elliptic inclusions. The major advantage in using the present analytical solution is that they can be conveniently computed in a global Cartesian coordinate system, which is widely used in many scientific and engineering computations. As an application example, the present analytical solutions have been used to investigate how the dip angle of an inclined elliptic inclusion affects the distribution patterns of the pore-fluid flow and excess pore-fluid pressure when the permeability ratio of the elliptic inclusion is of finite but nonzero values.  相似文献   
172.
通过对北京遥测地震台网近年来记录到的北京及邻区地震的震中分布,地震活动频度及能量释放强度的分析,得到本区地震活动在时间分布上具有“聚堆性”。在年发震频度,地震强度和能释放方面均具有双峰值特征,并且具有较好的一致性和同步性,在空间分布上具有条带特征,且形成北东~南西和北西~南东的两条相互交汇的条带。又通过统计分析得到本区发震概率最大的时间段是每年的10月前后,而地震主要发生在北西~南东带上。  相似文献   
173.
Based on four UK Schmidt Telescope (UKST) IIIa-j direct plates which had been digitized by the Automated Plate Measuring System (APM), a detailed identification of the disk galaxies in the Virgo cluster has been carried out. The certain and possible member galaxies are mainly selected from the updated Catalogue of 2096 Galaxies in the Virgo Cluster Area (VCC). The area of this identification covers a 85 square degree region centered on this cluster. As a result, we compiled a new catalogue of 340 certain and possible member disk galaxies, including 85 lenticulars (SO), 136 spirals (S) and 119 irregulars (Irr), where the APM-measured values of the position angle (P.A.) and diameters of 299 disk galaxies are provided. For at least 149 galaxies, the values of the P.A. and diameters are published for the first time.Comparison between the APM-measured P.A. and diameters of galaxies and those given by the Uppsala General Catalog of Galaxies (UGC) demonstrates the reliability of our data. The statistical properties and completeness of this database are also discussed. Compared with the UGC-given P.A. and diameters which were determined by eyes, our data has no selection effect owing to the instrument measurements. Within our searching region, this might be the largest and relatively complete photometric database published so far for investigating the spatial orientation of the spin vectors of galaxies in the Virgo cluster.  相似文献   
174.
175.
In this paper, the third-order derivative of velocity with respect to height is included in the traditional motion equations of the neutral PBL. The nonlinear equations are solved numerically to obtain the vertical distribution of wind in the PBL and some PBL characteristic parameters. Reasonable simulations of the Leipzig wind profile using these parameters show the success of this kind of nonlocal closure in a real PBL simulation.  相似文献   
176.
通过对胶东牟平—乳山热液脉状金,铅锌矿床成矿动力学控制规律的研究,说明了建立热液成矿反应体系的方法,并得出以下认识:(1)区域断裂构造活动,通过影响成矿反应体系的热力学性质和条件,控制元素的富集和分散。(2)热液成矿过程中容矿断裂活动可划分为两种作用方式:脆性破裂和韧—脆性张开,构成热液成矿的两种构造动力学环境。(3)热液成矿反应体系是一种开放的动态的热力学体系。断裂的脆性破裂阶段,使体系处于强烈的过饱和状态,矿质在远离平衡状态下快速结晶,加剧物质分异;在脆—韧性张开阶段,矿质在接近平衡态体系中缓慢晶出。(4)热液演化晚期,金在残余溶液中富集;当断裂再次发生构造脉动震颤时,早期形成的块状黄铁矿矿石碎裂,富金溶液充填其中,形成含裂隙金和晶隙金的富矿石。成矿体系热力学演化与构造动力学条件有利的匹配控制着富矿石的形成。  相似文献   
177.
有限不等厚介质中主层褶皱的模拟实验及理论研究   总被引:3,自引:0,他引:3       下载免费PDF全文
叶柏龙  何绍勋 《地球科学》1993,18(2):159-167
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178.
Metropolises are centers of politics, economy, culture and information, and also economic growth poles in comparatively large areas. After 1949, China's urban structure have changed greatly, from original "pyramid" shape into "upside -down pyramid" shape, that is, more megalopolises and metropolises, fewer medium-sized and small cities. The most distinguishing feature of urban population growth was the remarkable increase of population in megalopolises and metropolises. The key reason for urban population expansion is to want to obtain the benefits of scale -agglomeration economy of metropolises. The number of urban functions directly determines the quality and quantity of urban population. Metropolises appeal not only agricultural population but also the population of medium-sized and small cities, which put much more population pressure on metropolises. The ideal goals of scale-control of metropolitan population are discussed in terms of economy, society and ecollogy. In order to control the metropoli  相似文献   
179.
QSO objective prism survey was done for the field centered at 10h40m + 00°00. For the 348 objects selected, we present in this paper their positions,B J magnitudes, spectra, and finding charts. Based on the sample containing 163 QSO candidates with higher reliabilities (F 3), the surface density of QSO candidates withB J 20 is estimated to be about 4.5 per square degree.Work based on UKST plates.  相似文献   
180.
赵如意 《地质与勘探》2023,59(4):716-733
广东省大宝山矿床是南岭成矿带唯一的大型铜多金属矿床,此次研究在矿区中南部发现了细脉浸染状铜矿的新类型。为确定其是否为斑岩型铜矿的成因类型,本文在梳理南岭成矿带铜成矿条件和成矿规律的基础上,查明了矿区中南部英安斑岩的蚀变和铜矿化特征。综合研究认为南岭成矿带早侏罗世中酸性斑岩的小岩体较多,叠加多期断裂构造和碳酸盐岩建造,非常有利于铜多金属成矿物质的运移、富集。大宝山英安斑岩发育黑云母化、钾长石化、青磐岩化、绢英岩化、泥化等蚀变类型,铜矿化与绢英岩化、绿泥石化关系密切。大宝山铜矿中的英安斑岩沿逆冲推覆构造侵位并呈岩墙状产出,冷却过程中受区域构造应力产生了一组平行裂隙,岩浆房去气作用排出的热液沿裂隙蚀变围岩并充填成矿。大宝山斑岩型铜矿取得的找矿勘查成果表明,“全位成矿,缺位找矿”理念可以有效指导靶区圈定和老矿山外围(深部)找矿勘查,早侏罗世的南岭具有形成较大规模斑岩型铜矿的条件。  相似文献   
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