自流观测井泄漏的处理与水动力参数的试验研究

本文以苏１８井为例介绍了自流井泄漏的处理技术与井口动力参数的试验结果，采用钻也漏仪确定泄漏部位，内衬套管对环状间隙灌浆的堵漏技术，效果良好。采用不同泄水孔断面积对井口水动力参数进行了系列观测试验，对试验结果了分析，并推导了各参量间的函数关系，两者相当吻合，可以互相印证。     

JA96－866型ICAP光电直读光谱仪的智能系统设计

设计了Ｊａｒｒｅｌｌ－Ａｓｂ９６－８６６型电感耦合氩等离子炬（ＩＣＡＰ）光电直读光谱仪与ＩＢＭＰＣ２８６微型计算机的接口适配电路和相应的汇编支持程序，并用ＢｏｒｌａｎｄＣ＋＋２．０面向对象的程序设计语言开发了用户软件，实现了该光谱仪由ＰＤＰ－８Ａ到ＩＢＭＰＣ２８６的计算机换型改造，提高了仪器的智能化水平。     

地图符号系统的设计与实现

设计并实现了一套地图符号系统,提出了线状符号的附属属性设置实现,并采用了程序符号的思想实现一些相对特殊的如沙丘、河流、沼泽等地图符号,成功地对国家标准系列地形图图式进行了设计,实现了各种比例尺下的地图符号的绘制,完成了在Visual C 平台上所研制的地图符号软件系统的设计与开发.     

风机微观选址数学规划问题在GIS上实现求解的探讨

针对风力发电场建设过程中的风机微观选址问题，构造数学规划模型，并根据数学规划解题原理提出在GIS上求解的实现方法，提出了处理类似数学规划问题在GIS上实现的设想。     

NetCDF数据的编程式访问

NetCDF是一种面向数组型数据的描述和编码标准,目前广泛应用于大气科学、水文、海洋学、环境模拟、地球物理等诸多领域.用户可以借助多种方式方便地管理和操作NetCDF数据集.文章介绍NetCDF数据的编程式访问方法.该方法主要应用于数值预报模式,它涉及软件创建、参数配置、NetCDF文件结构、NetCDF接口函数库等.重点探讨了编程者在使用该方法时经常遇到的一些问题,并且给出了一个读取NCEP再分析文件的编程实例.     

Aspects of Modern Raytracing Application Design

Simulating the propagation of seismic energy in an inhomogeneous, possibly anisotropic earth model is a challenging problem, both theoretically and from the computer implementation side. While most publications in the geophysical literature focus on the theory, this paper illustrates how recent advances in computer science can be of great value to researchers who try to create numeric realizations of complex geophysical processes such as seismic raytracing. Modern concepts including object- oriented programming, combined with new and often free-of-charge development tools can significantly improve productivity and flexibility in implementing and exploring new ideas.A variety of issues important in wavefront-construction based raytracing are ad- dressed and it is demonstrated how modern program design may help researchers to more quickly produce better software implementations and free up time to focus on the fundamental theoretical problems.     

阻滑桩加固土坡稳定性分析的上限解法

从极限分析机动学方法出发,利用土的抗剪强度折减系数概念,建立了土坡的极限平衡状态方程,由此确定土坡的临界稳定安全系数及其相应的潜在破坏模式.对于典型问题,通过与现有极限平衡解和有限元数值解的对比分析,验证了这种上限解法的合理性.进而对于在给定的荷载条件下不能满足抗滑稳定性要求的土坡,考虑采用阻滑桩加固方式,根据桩侧有效土压力的合理分布模式确定桩体与滑动面相交的截面上等效抗滑力和抗滑力矩,利用极限分析上限定理建立了阻滑桩加固土坡的极限平衡状态方程,将桩侧土压力作为目标函数,运用数学规划方法确定了极限平衡状态时的临界桩侧土压力,以此为土坡加固中阻滑桩设计提供依据.通过数值计算与分析探讨了阻滑桩加固位置的优化布置等问题.     

Limit analysis of 2-D and 3-D structures based on an ellipsoid yield criterion

In this paper, a nonlinear numerical technique is developed to calculate the limit load and failure mode of structures obeying an ellipsoid yield criterion by means of the kinematic limit theorem, nonlinear programming theory and displacement-based finite element method. Using an associated flow rule, a general yield criterion expressed by an ellipsoid equation can be directly introduced into the kinematic theorem of limit analysis. The yield surface is not linearized and instead a nonlinear purely kinematic formulation is obtained. The nonlinear formulation has a smaller number of constraints and requires less computational effort than a linear formulation. By applying the finite element method, the kinematic limit analysis with an ellipsoid yield criterion is formulated as a nonlinear mathematical programming problem subject to only a small number of equality constraints. The objective function corresponds to the dissipation power which is to be minimized and an upper bound to the plastic limit load of a structure can then be calculated by solving the minimum optimization problem. An effective, direct iterative algorithm has been developed to solve the resulting nonlinear programming formulation. The calculation is based purely on kinematically admissible velocities. The stress field does not need to be calculated and the failure mode of structures can be obtained. The proposed method can be used to calculate the bearing capacity of clay soils in a direct way. Some examples are given to illustrate the validity and effectiveness of the proposed method.     

Optimization strategies for sediment reduction practices on roads in steep,forested terrain

Many forested steeplands in the western United States display a legacy of disturbances due to timber harvest, mining or wildfires, for example. Such disturbances have caused accelerated hillslope erosion, leading to increased sedimentation in fish‐bearing streams. Several restoration techniques have been implemented to address these problems in mountain catchments, many of which involve the removal of abandoned roads and re‐establishing drainage networks across road prisms. With limited restoration funds to be applied across large catchments, land managers are faced with deciding which areas and problems should be treated first, and by which technique, in order to design the most effective and cost‐effective sediment reduction strategy. Currently most restoration is conducted on a site‐specific scale according to uniform treatment policies. To create catchment‐scale policies for restoration, we developed two optimization models – dynamic programming and genetic algorithms – to determine the most cost‐effective treatment level for roads and stream crossings in a pilot study basin with approximately 700 road segments and crossings. These models considered the trade‐offs between the cost and effectiveness of different restoration strategies to minimize the predicted erosion from all forest roads within a catchment, while meeting a specified budget constraint. The optimal sediment reduction strategies developed by these models performed much better than two strategies of uniform erosion control which are commonly applied to road erosion problems by land managers, with sediment savings increased by an additional 48 to 80 per cent. These optimization models can be used to formulate the most cost‐effective restoration policy for sediment reduction on a catchment scale. Thus, cost savings can be applied to further restoration work within the catchment. Nevertheless, the models are based on erosion rates measured on past restoration sites, and need to be updated as additional monitoring studies evaluate long‐term basin response to erosion control treatments. Copyright © 2006 John Wiley & Sons, Ltd.