Embedded foundation in layered soil under dynamic excitations

The critical step in the substructure approach for the soil–structure interaction (SSI) problem is to determine the impedance functions (dynamic-stiffness coefficients) of the foundations. In the present study, a computational tool is developed to determine the impedance functions of foundation in layered soil medium. Cone frustums are used to model the foundation soil system. Cone frustums are developed based on wave propagation principles and force-equilibrium approach. The model is validated for its ability to represent the embedded foundation in layered medium by comparing the results with the rigorous analysis results. Various degrees of freedom, such as, horizontal, vertical and rocking are considered for this study.     

Research on seismic stress triggering

Introduction What is called seismic stress triggering refers to that stress change tensor produced by previous earthquake projected on the fault plane and slip direction of subsequent earthquakes, taking into account normal stress, pore pressure and friction coefficient, and Coulomb failure stress change DCFS can be obtained. If the direction of Coulomb failure stress changes are consistent with slip direction of subsequent seismic mechanism, e.g., Coulomb failure stress changes are positive…     

三重介质储渗系统与水驱油机理探讨——以塔河油田为例

探讨了塔河油田奥陶系碳酸盐岩油藏三重介质储渗系统的识别，划分和与之相对应的水驱油机理，具有高孔低渗特征的岩块系统主要靠自吸排油方式水驱油，在驱替压力和重力作用下，高孔高渗特征的洞穴系统水驱油近乎均匀推进，低孔高渗特征的裂缝系统水驱油易发生指进和突进。     

华北与东南沿海地区岩石介质差异性研究

通过地震活动性特征研究了华北与东南沿海地区岩石介质差异性，以唐山、海域及福建地区为例，计算了上述地区的视应力降和环境应力背景值，并用分形理论中的标度揭示了这种差异性的定量特征。结果表明，在华北地区（唐山与海城），环境应力值有强烈的涨落，而东南沿海地区（福建）其涨落并不明显，从而揭示了华北与东南沿海地区地壳岩石介质的差异性。这意味着上述地区的动力学特征在板块构造力作用下存在明显的差异。最后，应用动力学观点讨论了上述变化的复杂性和可能存在的问题。     

A study of crust and upper mantle structure in Northeastern region of China by means of synthetic seismograms

In this paper, structure models of the crust and upper mantle beneath each station have been obtained by way of fitting synthetic seismograms with P waveforms of deep focus teleseismic records from the 11 stations in the Northeastern Region of China. We have studied the structure in the region based on those models. Our results show that the medium of the crust and upper mantle is a layered structure with alternate high and low velocity layers within about 100 km under the region. The crustal thickness is about 31.8–35.8 km. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 471–479, 1991. This work is one part of the project funded by the State Seismological Bureau of China.     

上海及其邻区地震活动与某些“天,地”因子关系初探

本文报导了上海及其邻区M_s≥4 3/4级地震活动与地球自转速率和太阳黑子活动周期有关。据此可望找到该地区地震中期预报的指标。     

近实时中高空间分辨率森林火灾监测系统展望

森林火灾是最为常见的灾害之一,严重危及人类生命安全。及时准确监测森林火灾的发生及火场状况,对应对火灾及减少损失至关重要。当前,森林火灾卫星遥感监测主要以低空间分辨率的卫星遥感为主,空间分辨率过低导致无法探测规模较小火灾及掌握详细火场态势。针对这一问题,结合近些年中高空间分辨率卫星观测、共享及处理能力的发展,本文从森林火灾卫星遥感监测的基本原理、当前可用中高空间分辨率卫星数据及其特点、中高分辨率森林着火区监测算法,以及数据共享与云端存储与计算等4个技术环节,对森林火灾中高分辨率卫星遥感监测当前研究现状与存在问题进行了总结,阐述了近实时中高空间分辨率森林火灾监测系统的可行性。近实时中高空间分辨率森林火灾监测系统可对已有低空间分辨率森林火灾监测体系形成重要补充,依托其空间分辨率的优势有助于及早、准确发现小规模火情,进而为森林火灾的防治与管理提供更好支撑。     

受污染的云滴内NOx光化通量的计算

依靠云滴的射线光学模型,针对具有吸收的耗散介质,可得到形式完整的电磁波反射系数公式,并且可求得具有几何意义的实际折射角。文中重点讨论了云滴中污染内含物及其不同的内混合方式对光化通量增强因子的影响。结果表明:云滴的存在都能增强光子的光化通量,仅当吸收系数非常大时,云滴内光化通量才会减小;无论哪一种内混合方式,受污染的云滴内光化通量增强基本上稍大于先前的估计值;光化通量增强因子一般都在1.2～1.62之间,即光化通量增加了20%～62%;吸收系数为零时,增强因子与云滴半径无关;增强因子随云滴半径和吸收系数的增大而减小。当云滴半径接近1μm时,吸收系数的影响迅速减小。     

山西铝土矿的富集规律及进一步找矿方向

沉积铝土富矿资源形成于酸度较强而沉积物又不被介质溶解的平静稳定的沉积环境。成矿盆地斜坡下部的铝土矿带与疏铁矿相邻地段、成矿洼地、凹地及漏斗是铝土矿富矿赋存部位及找矿有利地段。