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991.
Uranium has been measured by homogenized fission track analysis in 34 samples of 22 achondrites. Potassium has been determined in aliquots of eleven of these. The results, combined with previous Al data, are not compatible with achondrite formation from chondritic material by previously suggested fractional melting or metal-sulfide segregation processes.  相似文献   
992.
The different methods and techniques employed in the theory of electromagnetic induction in thin sheets are reviewed and the methods for approximation to the solution are indicated. These depend on whether the sheet is closed or finite and on whether the integrated conductivity and/or the frequency of variations is high or low.Results for induction in finite sheets which are suitable for ocean modelling are given. These include sheets of perfect conductivity and sheets of finite conductivity which is either discontinuous or continuous at the boundary. The dependence of the “coastline effect” for a global ocean on the location of the edge of the continental shelf, the period of variation of the external field and the conductivity of the underlying earth is explained.  相似文献   
993.
994.
995.
Summary Relatively good correlation between such remote phenomena as microseisms, geomagnetic activity and ionospheric absorption of radio waves has been observed. These phenomena are probably connected by a considerably increased penetration of energetic particles into the atmosphere under conditions of geomagnetic activity.  相似文献   
996.
997.
Water Resources - The forked channel is a rare and poorly known type of branching channel, the distribution of flow in which is of key importance for water transport, economic activities, and water...  相似文献   
998.
Izvestiya, Physics of the Solid Earth - Abstract—In their paper published in Izvestiya, Physics of the Solid Earth, G.A. Sobolev et al. (2020) discussed the results of their study. Firstly,...  相似文献   
999.
Ocean Dynamics - The Eastern Kamchatka Current (EKC) is the western boundary current of the North Pacific subpolar gyre. Southeast of the Kamchatka Peninsula lies a large anticyclonic eddy, the...  相似文献   
1000.
A statistical analysis of the peak acceleration demands for nonstructural components (NSCs) supported on a variety of stiff and flexible inelastic regular moment‐resisting frame structures with periods from 0.3 to 3.0 s exposed to 40 far‐field ground motions is presented. Peak component acceleration (PCA) demands were quantified based on the floor response spectrum (FRS) method without considering dynamic interaction effects. This study evaluated the main factors that influence the amplification or decrease of FRS values caused by inelasticity in the primary structure in three distinct spectral regions namely long‐period, fundamental‐period, and short‐period region. The amplification or decrease of peak elastic acceleration demands depends on the location of the NSC in the supporting structure, periods of the component and building, damping ratio of the component, and level of inelasticity of the supporting structure. While FRS values at the initial modal periods of the supporting structure are reduced due to inelastic action in the primary structure, the region between the modal periods experiences an increase in PCA demands. A parameter denoted as acceleration response modification factor (Racc) was proposed to quantify this reduction/increase in PCA demands. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   
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