盆地岩石圈结构与油气成藏及分布

本文综述了大陆岩石圈研究现状和克拉通盆地、裂谷盆地和前陆盆地的岩石圈结构特征,指出在古裂谷、褶皱带或区域性深断裂等陆壳构造薄弱带上发育起来的多期叠合盆地,具有很好的含油气前景。大型含油气盆地往往存在地幔上隆、地壳减薄和地壳内低速层,盆地基底沉降与盖层沉积厚度较大。适度的后期构造活动改造和岩浆活动有利于沉积盆地内油气生成与保存。     

System identification of the Vincent Thomas suspension bridge using earthquake records

The Vincent Thomas Bridge in the Los Angeles metropolitan area, is a critical artery for commercial traffic flow in and out of the Los Angeles Harbor, and is at risk in the seismically active Southern California region, particularly because it straddles the Palos Verdes fault zone. A combination of linear and non‐linear system identification techniques is employed to obtain a complete reduced‐order, multi‐input–multi‐output (MIMO) dynamic model of the Vincent Thomas Bridge based on the dynamic response of the structure to the 1987 Whittier and 1994 Northridge earthquakes. Starting with the available acceleration measurements (which consists of 15 accelerometers on the bridge structure and 10 accelerometers at various locations on its base), an efficient least‐squares‐based time‐domain identification procedure is applied to the data set to develop a reduced‐order, equivalent linear, multi‐degree‐of‐freedom model. Although not the main focus of this study, the linear system identification method is also combined with a non‐parametric identification technique, to generate a reduced‐order non‐linear mathematical model suitable for use in subsequent studies to predict, with good fidelity, the total response of the bridge under arbitrary dynamic environments. Results of this study yield measurements of the equivalent linear modal properties (frequencies, mode shapes and non‐proportional damping) as well as quantitative measures of the extent and nature of non‐linear interaction forces arising from strong ground shaking. It is shown that, for the particular subset of observations used in the identification procedure, the apparent non‐linearities in the system restoring forces are quite significant, and they contribute substantially to the improved fidelity of the model. Also shown is the potential of the identification technique under discussion to detect slight changes in the structure's influence coefficients, which may be indicators of damage and degradation in the structure being monitored. Difficulties associated with accurately estimating damping for lightly damped long‐span structures from their earthquake response are discussed. The technical issues raised in this paper indicate the need for added spatial resolution in sensor instrumentation to obtain identified mathematical models of structural systems with the broadest range of validity. Copyright © 2003 John Wiley & Sons, Ltd.     

数字化测绘技术在城镇地籍测量中的应用

数字化测绘是目前较为流行的测量方式，其技术本身也日渐成熟。文章简述了数字化测绘技术在城镇地籍测量中作业流程、实施过程与地籍管理信息系统的建立过程。     

党政机关电子政务建设的若干问题

以从事政务信息化建设的实践经验为基础 ,对电子政务建设的基本问题进行了系统分析 ,内容包括 :信息关系和信息控制、信息分类、数据库结构、软件系统开发思路、电子政务的工作目标、服务对象、服务模式、电子政务建设的技术措施等。     

利用信噪比削弱GPS多路径效应的研究

由于多路径误差的非时空相关性,使其成为双差模型中较难解除的误差源。本文利用观测值的信噪比对观测值质量进行评价,通过降低受多路径效应影响的观测值的权重,从而达到削减多路径误差的目的。最后通过实验数据解算结果的重复性验证了此方法的有效性和可靠性。     

STRUCTURAL CHARACTERISTICS OF THE NIUSHOU MOUNTAIN AND ITS GEOLOGICAL SIGNIFICANCE IN CENTRAL NINGXIA

There are many thrust-related structures occurring in the Paleozoic strata of the Niushou Mountain in the central part of Ningxia Hui Autonomous Region. The fault-related folds are the typical structures in this area. Based on the analysis about these structures and their relationships, the processes by which these structures of the Miboshan Formation were formed are reconstructed, and the strata underwent about three stages of deformation: (1) horizontal shortening, (2) folding, and (3) thrusting. And the fact that the Niushou Mountain is the leading edge of an old thrust sheet was proved, the Niushou Mountain, the Daluo Mountain and the Xiaoluo Mountain together constitute the front part of this old thrust zone, so the Niushou Mountain and the Ordovician strata in the central and southern parts of Ningxia now are likely allochthons. In the period from middle Ordovician to Devonian, the areas of the central and southern Ningxia belonged to the back-arc foreland basin of North Qilianshan orogen, which was adjacent to the continent in the north. In the later part of the early Paleozoic period, the Niushou Mountain was formed after the closure of the back-arc foreland basin.     

Regional Fault Systems of Qaidam Basin and Adjacent Orogenic Belts

The purpose of this paper is to analyze the regional fault systems of Qaidam basin and ad-jacent orogenic belts. Field investigation and seismic interpretation indicate that five regional fault sys-tans occurred in the Qaidam and adjacent nment.qin belts, controlling the development and evolution of the Qaidam basin. These fault systems are: (1)north Qaidam-Qilian Mountain fault system; (2) south Qaidam-East Kunhm Mountain fault system;（3）Altun strike-slip fault system; (4) Elashan strike-slip fault system, and (5) Gansen-Xiaochaidan fault system. It is indicated that the fault systems controlled the orientation of the Qaidam basin, the formation and distribution of secondary faults within the basin,the migration of depocenters and the distribution of hydrocarbon accmnulation belt.     

BP神经网络模型在重庆伏旱预测中的应用研究

采用气象要素定义伏旱指数，利用小波分析等方法分析重庆地区伏旱变化特征，最后采用BP神经网络模型对伏旱进行预测试验，结果表明，重庆伏旱变化具有明显的阶段性特征，而基于BP神经网络模型的伏旱预测模型预测效果良好，可以应用于实际预测。     

卫星测高问题的球谐级数解法

研究了球界面下卫星测高问题的解法，利用有限逼近方法得到了下列结论：若陆地部分是球冠，则卫星测高问题的解可以转换成关于球谐级数位系统的线性方程组。同时证明了常用的Stokes问题、Dirichlet问题、Neumann问题可以看成卫星测高问题的特殊情况。     

一种在异构系统中实现负载平衡的方法

提出了在异构系统实现负载平衡的区域分解算法和实现负载平衡的计算方法，利用它的负反馈性质解决了异构系统处理机计算速度测量误差造成的负载测量不准问题，并对处理机速度变化，速度测量误差、处理机数量、网格点计算量的分布等因素的影响进行了计算，结果表明本方法具有很强的平衡负载能力和较强的适应性；根据计算结果提出了解决模式网格点计算量不易测量问题的解决方案，并用扩散方程和模拟物理过程进行试验，试验表明这种方法是可行的，平衡负载的效果十分显著。