频域激发极化法中体极化与面极化内在联系的探讨   总被引：2，自引：0，他引：2  

王继伦 《地球物理学报》1989,32(5):593-599

矿化的体极化介质,其激发极化效应来自其中所含电子导电矿物颗粒的表面极化效应。基于上述认识,本文从理论上推导出含球状电子导体的体极化介质复电阻率的“微观”数学表达式。将它与体极化介质复电阻率的“宏观”表达式--Cole-Cole模型相比较,得出了:1.Cole-Cole模型中的特征参量与球状电子导体的表面极化系数、含量以及导体半径等的综合关系式;2.电子导体表面极化系数在频域中的一般表达式。这表达式同目前在实验室中观测到的结果是一致的。  相似文献   

Basin-scale relations via conditioning     

B. M. Troutman  M. R. Karlinger  D. P. Guertin 《Stochastic Environmental Research and Risk Assessment (SERRA)》1989,3(2):111-133

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Regional variation of mechanical and chemical denudation,upper Colorado River Basin,U.S.A.     

Karl-Heinz Schmidt 《地球表面变化过程与地形》1985,10(5):497-508

The variation of mechanical and chemical denudation is investigated using discharge and sediment yield data from the Upper Colorado River System. Annual precipitation ranges from approximately 150 mm to 1500 mm. Mean specific yield ranges from 0-2 1/s km² ( = 6 mm p a) to 151/s km² ( = 475 mm p a). The hydrological-geomorphological system adjusts itself to these varying climatic conditions; in some areas, however, the effects of lithology or land use seem to override the climatic controls. It is demonstrated that the increase in the absolute and particularly the relative amount of suspended sediment is closely related to a decrease in annual runoff and to an increase in the importance of high magnitude/low frequency events. This indicates that in areas of low annual runoff and high runoff variability, soluble rocks are more resistant than in more humid areas. During high magnitude/low frequency events, suspended sediment concentrations and loads are very high in semiarid areas due to sparse vegetation cover and dominance of direct runoff. Events of moderate magnitude and frequency, which in more humid areas transport most of the dissolved load, seldom occur. The trend towards increasing mechanical denudation is even observed in areas of very low runoff (0-221/s km² = 7 mm p a). The peak of sediment yield in dry areas seems to approximate the point of no runoff very closely. Mechanical and chemical denudation are of equal importance at a runoff of about 300 mm per year.  相似文献   

高频多普勒台阵中的若干技术问题   总被引：2，自引：0，他引：2       下载免费PDF全文

李利斌  吴振华  宁百齐  李钧 《地球物理学报》1987,30(6):560-565

为了研究电离层动力学特性,1985年9月在武汉建成了一个由三个台站组成的高频多普勒台阵和卫星信标法拉第台阵。文中介绍了这个台阵的布局和多普勒接收系统中的一些技术细节。这些技术措施保证了在多普勒图中清晰地显示多径现象和有效地消除小不均匀体的影响。最后还简单地介绍了这个台阵一年来的实测情况。  相似文献   

1983年菏泽5.9级地震前后小震频数及能量空间分布的分形特征     

蒋海昆 《地震》1993,(6):15-20

本文对菏泽地震为例,从频数及能量两方面对地震不均匀空间颁的分形特征进行研究,并探讨其预报含义。结果表明,地震频数及地震能量空间分布均表现出统计意义上的自相似特征,并且前者的分布结构较后者列为复杂。菏泽地震前几年的“降维”中视为中期预报的一个显著指标,而动态均值则可作为判断“降维”的一个较好标准;ｔ检验表明能量分布的降维较频数分布更为显著,并且其对中强地震孕育过程各阶段的反映似也列为灵敏,降维之后的  相似文献   

国外区域洪水频率分析方法研究进展   总被引：6，自引：2，他引：6       下载免费PDF全文

熊立华  郭生练  王才君 《水科学进展》2004,15(2):261-267

总结了国际上区域洪水频率分析方法的最新研究进展。对经典的标度洪水法进行了评述,阐述了进行区域洪水频率分析时应该遵守的几个原则,总结了关于数据检查、水文分区识别及水文分区均匀性检验等几个关键问题的研究结果。  相似文献   

An Effective Method for Free Vibration of Plate on Elastic Half Space     

WangYuanhan GongWenhui 《中国地质大学学报(英文版)》2004,15(4):401-408

The vibration analysis of a plate on an elastic foundation is an important problem in engineering. It is the interaction of a plate with the three-dimensional half space and the plate is usually loaded from both the upper and lower surfaces. The contact pressure from the soil can not be predefined. According to Lambs solution for a single oscillating force acting on a point on the surface of an elastic half space, and the relevant approximation formulae, a relation between the local pressure and the deflection of the plate has been proposed. Based on this analysis, the reaction of the soil can be represented as the deformation of the plate. Therefore, the plate can be separated from the soil and only needs to be divided by a number of elements in the analysis. The following procedure is the same as the standard finite element method. This is a semi-analytical and semi-numerical method. It has been applied to the dynamic analysis of circular or rectangular plates on the elastic half space, at low or high frequency vibration, and on rigid, soft or flexible foundations. The results show that this method is versatile and highly accurate.  相似文献   

Experimental Study of Mechanical Behaviour of Rock Joints Under Cyclic Loading   总被引：3，自引：5，他引：3  

M. K. Jafari  F. Pellet  M. Boulon  K. Amini Hosseini 《Rock Mechanics and Rock Engineering》2004,37(1):3-23

Summary Evaluation of the effects of small repetitive earthquakes on the strength parameters of rock joints in active seismic zones is of interest of the designers of underground constructions. In order to evaluate these effects, it is necessary to study the behaviour of rock joints under dynamic and cyclic loadings. This paper presents the results of a systematic study on the behaviour of artificial rock joints subjected to cyclic shearing. More than 30 identical replicas have been tested using triaxial compression devices under different conditions of monotonic and cyclic loading. At the first stage a few samples have been tested in monotonic loading modes under various confining pressures and rate of displacement. In the second series of tests, small cyclic loads were applied on the samples for increasing number of cycles, frequency levels and stress amplitudes. These were then followed by monotonic loading again. The variations of maximum and residual shear strengths for each test have been studied. The results show increase of shear strength as a result of the increase in confining pressure and they display decrease of shear strength due to the increase of rate of loading, number of cycles, frequency levels and stress amplitudes.  相似文献   

复杂地形条件下的可控源音频大地电磁测深数据二维反演技术及应用效果   总被引：12，自引：0，他引：12  

雷达  孟小红  王书民  李汝传  方慧  赵富刚 《物探与化探》2004,28(4):323-326

复杂地形严重地影响可控源音频大地电磁测深(CSAMT)的解释结果,为此,笔者考虑了地形的影响,将地电断面模型经过精细剖分,对模型正演计算的数据进行CSAMT二维反演,得出的结果与正演模型的形态基本一致,获得的电性断面能很好地反映地下地质结构,与实际地质资料相吻合,证实了该方法的正确性和有效性。  相似文献   

SOHM-4型氢原子钟的设计改进与初步性能   总被引：1，自引：3，他引：1  

彭科  张燕军  张为群  张一平  蔡勇  翟造成 《时间频率学报》2004,27(1):41-47

氢原子钟是一种最稳定的 (除极短测量时间间隔之外 )频率标准 ,但是环境温度变化及微波谐振腔老化会引起原子钟输出频率的变化 ,从而导致氢原子钟长期性能变差。为了减小这些影响 ,可借助一种自动调谐器来确保谐振腔的频率始终工作在所需的频率上 ,并采用新的温度控制系统来改善氢原子钟的长期性能。针对这些年来许多氢钟出现的有关问题 ,上海天文台在借鉴国外氢钟实验室经验的基础之上 ,对原有氢钟进行了技术改造 ,并为国家授时中心研制了SOHM - 4型氢原子钟。对该型氢原子钟技术改造特点作了介绍 ,并给出了期望的性能指标及初步的测试结果  相似文献