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951.
桂北及桂中大瑶山西侧泥盆纪层控型站矿床成因研究表明,矿床形成赋矿盆地的海平面变化密切相关,它们是“层、系、相、位”四位一体主因素地质场作用的结果,这一新的矿床成因新模式可以概括为:区域赋矿层位与层序边界面关系密切,研究区内共划分出7个 序边界面,其中SB1(I),SB3(Ⅲ)及SB7(I)是主要的区域性赋 层位;矿体一般产于I型层序边界面之上,或产于Ⅱ,Ⅲ层序边界面之下;容矿主岩与一定的沉积体系域 相似文献
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953.
地壳的新的地球物理模型与石油的无机成因说 总被引:18,自引:0,他引:18
根据深地震测深法,大爆破,天然地震转换波法,区域对比折射比,共深度点法,结合重,磁,电法等地球物理方法,建立了含油气盆地的“缺花岗岩”型的地壳模型,这种模型地地质条件下费托合成无机油气;近期提出的深部-浅部“立交桥模型”更为这种油气生成,运移成藏提供了可能;而沥青,干酪根的Pb,Sr,Nd同位素数据则为原油的无机成因揭示了十分可靠的证据,原油中Si-C键有机化全物的发现更为这种形成机理提供了一个重 相似文献
954.
Helmholtz's equation with a variable wavenumber is solved for a point force through use of a first-order differential equation system approach. Since the system matrix in this formulation is non-constant, an eigensolution is no longer valid and recourse has to be made to approximate techniques such as series expansions and Picard iterations. These techniques can accommodate in principle any variation of the wavenumber with position and are applicable to scalar wave propagation in one, two and three dimensions, with the latter two cases requiring radial symmetry. As shown in the examples, good solution accuracy can be achieved in the near field region, irrespective of frequency, for the particular case examined, namely a wavenumber which increases (or decreases) as the square root of the radial distance from source to receiver. Finally, the resulting Green's functions can be used as kernels within the context of boundary element type solutions to study scalar wave scattering in inhomogeneous media. 相似文献
955.
OBSERVATION AND MODEL ANALYSES OF POSITIVE CLOUD-TO-GROUND LIGHTNING IN MESOSCALE CONVECTIVE SYSTEMS 总被引:1,自引:0,他引:1
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Yan Muhong Guo Changming Qie Xiushu Ge Zhengmo Zhang Guangshu Lanzhou Institute of Plateau Atmospheric Physics Academia Sinica Lanzhou 《Acta Meteorologica Sinica》1992,(4)
The analyses of spatial and temporal characteristics of positive cloud-to-ground(CG)lightning for four mesoscaleconvective systems and two severe local convective systems in 1989 and 1990 show that positive CG flash rate usuallyhas two peak values.The major peak occurs during the developing stage of the storm and most of the positive CGflashes originate at the lower part of the storm.The minor occurs during the dissipative stage of the storm and most ofthe positive CG flashes originate at the upper part of the storm,especially in the region of the wind divergence in thestorm anvil.The positive CG flash rate is almost an order of magnitude larger in the developing stage than in thedissipative stage.The appearing time of the peak of negative CG flash rate is in accordance with that of the valley of pos-itive CG flash rate.The higher the intensity of the radar echo,the higher the positive CG flash rate.Most of the positive CG flashes oc-cur when the weak echo area is larger,and mostly originate in the region where the radar echo intensity is about 10dBzand in the back region of the moving storms.The spatial distribution of the positive CG flashes is much more dispersivethan that of the negative.The mesoscale analysis reveals a bipolar lightning pattern.The mean bipole--length reaches itsminimum during the mature stage of the storm and reaches the maximum during the developing stage of the storm.The vertical distribution of the charge density is calculated by a one-dimensional charging model.Then,we discussthe producing condition of the positive CG lightning and forming cause of charge structure mentioned above. 相似文献
956.
浅谈寻找极谱催化波新体系的方法 总被引:1,自引:0,他引:1
本文从催化波的基础理论出发,推论出一些寻找各种类型极谱催化波新体系的方法。总结出从已有的光度测定体系中试验新的极谱催化波体系;当一种金属离子与一种有机试剂虽能形成沉淀,但其浓度甚微达不到它们的溶度积时,可能出现用于测定这种金属离子的催化波;变滴汞电极为活性金属电极的方法;一些中性盐在极谱催化波中的应用等实践经验和规律。 相似文献
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The nature of horizontal anomalies and anomalous current systems in the region of the southern Indian peninsula is theoretically
calculated with the aid of a thin sheet algorithm for northward and westward polarizations of a uniform inducing magnetic
Held of period 20 min. The numerical model of the geoelectric structure is the one devised by Agarwal and Weaver (1989). The
model results indicate the correspondence between the general features of the computed horizontal anomalies and the observed
anomalies both at temporary array stations and at two permanent magnetic observatories (ANN and TRD). On the basis of model
estimates of apparent resistivity and phase it is suggested that a one-dimensional interpretation of the sub-surface conductivity
structure is valid near two of the array stations, whereas at all other coastal and inland stations, two-or three-dimensional
interpretations of magnetotelluric (MT) data are required. 相似文献
960.
曹庄片麻杂岩包括35亿年的表壳岩及三个不同时期的复期正片麻岩。水厂片麻杂岩包括水厂表壳岩及侵入其中的淡花岗岩和紫苏花岗岩,后者年龄为26.5亿年。 相似文献