全型垂直涡度倾向方程和倾斜涡度发展   总被引：96，自引：21，他引：75  

吴国雄  刘还珠 《气象学报》1999,57(1):1-15

文中证明了不仅包括动力因子,而且包括热力因子、摩擦耗散及非绝热加热作用的和可用于三维空间的全型垂直涡度倾向方程。证明经典的、平面上的涡度方程只是它的特例。并且用该全型涡度方程严格证明了倾斜涡度发展（ＳＶＤ）理论。沿着倾斜等熵面下滑的气块,当热力参数ＣＤ减小时,其垂直涡度将发展。最后通过用θ坐标模式模拟一次西南低涡的形成,证明ＳＶＤ引起的涡度发展要比传统所考虑的辐合项的贡献大一个量级。  相似文献   

鄂尔多斯盆地下奥陶统碳酸盐岩有机相类型及生烃潜力   总被引：26，自引：0，他引：26  

夏新宇  张文正 《沉积学报》1999,17(4):638-643

对鄂尔多斯盆地下奥陶统马家沟组碳酸盐岩的各种沉积环境的有机相特征进行了研究,结果表明平均有机碳丰度最高的是陆缘斜坡相碳酸盐岩(0.26%),其次是膏盐湖(0.22%)、膏云坪(0.21%),而开阔海、云坪和滩等环境的碳酸盐岩有机碳平均含量较低(<0.20%);碳酸盐岩干酪根样品多数为富氧、贫氢,显示其有机质类型较差;岩石地球化学特征和生物化石特征反映出陆缘斜坡处于相对还原的环境,而其他沉积环境则为氧化环境。鄂尔多斯盆地下奥陶统的大部分碳酸盐岩处于生烃潜力较差的C～D相。从有机质数量、有机相类型来判断,鄂尔多斯盆地下奥陶统碳酸盐岩不是好烃源岩,难以形成具有一定规模的气田。  相似文献   

Refraction Effect in Geothermal Heat Flow Due to a 3-D Prism in a Two-Layered Earth     

Hvoždara  M.  Valkovlč  L. 《Studia Geophysica et Geodaetica》1999,43(4):407-426

A mathematical model of the disturbance of the stationary geothermal field due to a three-dimensional perturbing body embedded near the surface of a two layered earth. The theoretical analysis is based on the generalized theory of the double-layer potential, similar to the boundary integral method likely to direct current geoelectricity problems. Special attention is paid to cases in which a pan of the body's surface is tangential to the planar boundaries of the substratum or of the surface of the earth The numerical calculations are performed for a three-dimensional prism using methods similar to the boundary element method (BEM). Numerous graphs are shown for the disturbance of the temperature field and of the heat flow on the surface of the earth and along vertical profiles (boreholes).  相似文献   

石油企业抗震防灾规划信息管理系统的设计   总被引：1，自引：0，他引：1       下载免费PDF全文

曾海容  徐鹏飞  宋惠珍  王优龙 《地震地质》1999,21(3):283-287

基于石油企业抗震防灾工作对网络与数据库的信息管理系统的需求,对数据库产品进行了简要分析,并根据石油企业抗震防迷规划的需求和信息管理的一般模式,提出了石油企业抗震防灾规划信息计算机管理系统的设想。认为,以Ｍｉｃｒｏｓｏｆｔ Ａｃｃｅｓｓ数据库软件为基础,利用ＶＢ或ＶＣ等可视化前端应用开发工具,是目前比较好的方案,它将使石油企业抗震防灾规划工作在办公自动化方面迈向新的台阶。  相似文献   

Numerical simulation of ground flow caused by seismic liquefaction     

S. Tamate  I. Towhata 《Soil Dynamics and Earthquake Engineering》1999,18(7):1079

Flow failure of sandy subsoil induced by seismic liquefaction is known to cause significant damage to structures. It is induced not only by the dynamic forces exerted by seismic acceleration but also by the static gravity force in consequence of the topography of the ground. The ground flow may sometimes continue after the end of the seismic loading and finally the ground is significantly deformed to cause a failure.This paper numerically predicts the magnitude of flow that could occur when soil liquefaction continues for a sufficiently long period. It is considered that liquefied soil behaves like a viscous liquid, and hence, ground flow is governed by the principle of minimum potential energy. In the calculation, liquefied sand is assumed to be a viscous liquid that deforms in undrained conditions with its volume remaining constant. To consider the non-linearity due to large displacement, the updated Lagrangian method is used to solve the equation of motion. The Newmark β method is employed to calculate the time history of the ground motion. Finally, a simulation using this calculation method shows that the proposed method gives reasonable results for the conditions indicated.  相似文献   

Dynamic soil–structure interaction analysis via coupled finite-element–boundary-element method     

M. Yazdchi  N. Khalili  S. Valliappan 《Soil Dynamics and Earthquake Engineering》1999,18(7):502

In this paper, a study on the transient response of an elastic structure embedded in a homogeneous, isotropic and linearly elastic half-plane is presented. Transient dynamic and seismic forces are considered in the analysis. The numerical method employed is the coupled Finite-Element–Boundary-Element technique (FE–BE). The finite element method (FEM) is used for discretization of the near field and the boundary element method (BEM) is employed to model the semi-infinite far field. These two methods are coupled through equilibrium and compatibility conditions at the soil–structure interface. Effects of non-zero initial conditions due to the pre-dynamic loads and/or self-weight of the structure are included in the transient boundary element formulation. Hence, it is possible to analyse practical cases (such as dam–foundation systems) involving initial conditions due to the pre-seismic loads such as water pressure and self-weight of the dam. As an application of the proposed formulation, a gravity dam has been analysed and the results for different foundation stiffness are presented. The results of the analysis indicate the importance of including the foundation stiffness and thus the dam–foundation interaction.  相似文献   

Power Law Distribution of Broadband Radiated Energy for Global Seismicity     

Wu ZhongliangInstitute of Geophysics  China Seismologlcal Bureau  Beijing  China 《中国地震研究》1999,(4)

The claim that there exists a transition of earthquake energy distribution between small and large earthquakes is checked using broadband radiated energy of earthquakes for global seismicity. Scattering of the relation between the magnitude and the broadband radiated energy makes it necessary to use the energy data directly. Rank-ordering statistics is applied to enhance the resolution in retrieving the power law distribution with undersampled data, namely, a few tens of events. Seen in the perspective of broadband radiated energy with higher resolution, there is no evidence for the kink in the frequency-energy distribution for large and small earthquakes. Instead, a single power law can well explain the data. For earthquakes with energy larger than 10~(14) J, we find that the number N of events with energy E depends on E via N ∝ E-B, with the scaling constant B = 0.64 ± 0.04, corresponding to b = 0.95± 0.06.  相似文献   

从岩相古地理论中国南方石炭系油气潜景   总被引：8，自引：4，他引：4       下载免费PDF全文

冯增昭  杨玉卿  金振奎  鲍志东 《古地理学报》1999,1(4):86-92

石炭系是中国南方重要的海相含油气地层之一。下石炭统的油气生成条件比上石炭统的好,这和早石炭世的盆地面积较大有关。石炭系下伏的志留系和上覆的二叠系的油气生成条件比石炭系还要好。上石炭统的油气储集条件比下石炭统的好,这和上石炭统的白云岩和滩相石灰岩分布较广有关。石炭系油气藏的直接盖层是下二叠统下部的梁山组,区域盖层是中新生代的泥岩为主的地层。南方石炭系油气生储盖条件的配置关系相当好。但是,南方石炭系以及整个古生代和三叠纪海相地层均经历了多次大的构造变动,其油气藏形成条件遭受相当大的破坏。在有利的生储配置关系的基础上,在区域盖层和保存条件较好的及面积较大的中新生代沉积盆地中,尤其是在邻近石炭系本身或其下伏志留系油气源岩的地区,是寻找和发现石炭系新的油气藏的有利地区。  相似文献   

广义坐标系η中的位涡方程   总被引：1，自引：0，他引：1  

袁卓建 《大气科学》1999,23(2):199-204

给出了在广义坐标系（η）中导出的位涡方程,以及它分别在笛卡尔坐标（z)、气压坐标（p）或等熵坐标（θ）时的具体表达式。结果表明,由此得出的各坐标系的位涡方程和过去人们在各坐标系中分别推出的位涡方程一致。并且得出位涡在绝热和无摩擦的条件下守恒。  相似文献   

中国南方树皮煤的生油潜力   总被引：6，自引：0，他引：6  

张爱云  翁成敏  蔡云开 《地学前缘》1999,6(Z1):209-215

中国南方晚二叠世龙潭煤系中的树皮煤主要分布在江苏南部、浙江长兴、安徽广德、江西乐平、贵州六盘水、湖南对阳等地区。将树皮煤作为烃源岩研究,对中国南方油气资源的寻找、勘查和评价具有十分重要的意义。文中通过对树皮煤的形成条件。有机质类型、演化程度以及各种显微组分对煤成烃的贡献的分析,讨论树皮煤的生烃潜力。并根据龙潭煤系生烃潜力、油气显示和生储盖的组合特征,讨论了龙潭煤系的成藏前景。  相似文献