Anisotropy of the apparent resistivity variation rate near the epicentral region for strong earthquakes

IntroductionThe geo-electrical anisotropy before earthquake is of special significance for the prediction of earthquake location and for the research on crustal stress status near the epicentral region. The anisotropy has been studied from various aspects (CHEN, et al, 1983; QIAN, et al, 1985, 1996; LU, et al, 1990a; MAO, et al, 1995; RUAN, et al, 1999). But the anisotropic phenomena presented by geo-electrical data are not practically satisfactory and not clear as compared with the res…     

Evolution of 3D tectonic stress field and fault movement in North China

IntroductionThe research on stress field interior the Earth is an either relative old or young branch of geoscience. Early in the 20th century, in order to learn the state of inner stress field, a few scholars had used simple ideal model to analyze big scale tectonic conformations and activities according to tide, gravity, rotation and inner thermal materials. So far, lots of problems on the state of the Earth stress field have not been solved completely yet. The origin of stress field, the d…     

TAKING INTO ACCOUNT THE EFFECT OF SECONDARY FLOWS IN DEPTH AVERAGED MORPHODYNAMIC SIMULATIONS

1 INTRODUCTIONThe numerical simulation of morphological changes in rivers, estuaries and coastal areas is because ofits econondcal merit an outstanding scientific task. The comPlexity of the problem is connected with theheterogeneity of the sediment material, an adequate rePresentation of the involved hydrOdynndc stressesand the large comPutational effort fOr long term simulations.Although the aPpllcation of three dimensional models tO engineering problems is increasing and wellvalldate…     

Electric conductivity of Fe2SiO4–Fe3O4 spinel solid solutions

 The spinel solid solution was found to exist in the whole range between Fe₃O₄ and γ-Fe₂SiO₄ at over 10 GPa. The resistivity of Fe_{3− x} Si _x O₄ (0.0<x<0.288) was measured in the temperature range of 80∼300 K by the AC impedance method. Electron hopping between Fe³⁺ and Fe²⁺ in the octahedral site of iron-rich phases gives a large electric conductivity at room temperature. The activation energy of the electron hopping becomes larger with increasing γ-Fe₂SiO₄ component. A nonlinear change in electric conductivity is not simply caused by the statistical probability of Fe³⁺–Fe²⁺ electron hopping with increasing the total Si content. This is probably because a large number of Si⁴⁺ ions occupies the octahedral site and the adjacent Fe²⁺ keeping the local electric neutrality around Si⁴⁺ makes a cluster, which generates a local deformation by Si substitution. The temperature dependence of the conductivity of solid solutions indicates the Verwey transition temperature, which decreases from 124(±2) K at x=0 (Fe₃O₄) to 102(±5) K at x=0.288, and the electric conductivity gap at the transition temperature decreases with Si⁴⁺ substitution. Received: 15 March 2000 / Accepted: 4 September 2000     

农业生态的化学元素分类及其与作物优质高产的关系

利用国家科学技术成果，并根据国内外研究现状，将103个化学元素分成对作物生长发育、增产起显著作用、起一定作用、起有害作用和起未知作用4个农业生态元素类型，进而论述了它们与作物优质高产的关系。     

数字式智能化锚索预应力传感器的研究与设计

预应力传感器是锚固工程，预应力混凝土工程，预应力桥梁工程等领域进行监测，研究与试验必不可少的测量用传感器，在分析预应力传感器[研究现状的基础上，详细了介绍了数字式智能化锚索预应力传感器的工作原理，结论设计，计量检定结果，主要特点和应用情况。     

单波高精度测距系统的研究

本文介绍了测距精度优于１０＾－６的自动高精度测距系统的构成、原理及春应用。     

齿轮弯曲强度的有限元分析法

论述了齿轮弯曲强度的有限元分析方法，同传统的方法相比能准确地获得齿轮的真实应力场，为齿轮强度计算提供可靠的依据。     

ALow-order Model of Two-dimensional Fluid Dynamics on the Surface of a Sphere

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Faulting in zones of lithospheric extension: Quantitative analysis of natural and experimental data

Quantitative relationships between major fault parameters from geological observations and laboratory experiments are compared. Relationships are established between fault length, number, depth of fault penetration, amplitude of displacement and other characteristics. The width of destruction zones is estimated. Spacing between parallel faults of compatible length is evaluated. It is shown that there is a stable correlation between fault length and number, which is independent from the mode of loading the material under destruction. Destruction of the lithosphere is believed to occur according to the laws of deformation of Maxwell elasto-viscous body.