径向水平井弯曲转向机构影响因素仿真研究

针对径向水平井钻进中钻杆弯曲转向前进运动困难的问题,通过建立弯曲转向机构仿真有限元模型,对其主要影响因素:滑道轨迹曲率、间隙、工作压力、滚轮形状与位置和钻杆壁厚等用ANSYS软件进行仿真研究。研究表明:影响截面变形的主要因素是滑道曲率的改变和滑道摩擦因数,钻井失败时钻杆所受阻力的增大不是因为升高工作压力导致截面变形过大与滑道干涉所致,钻杆经校直段,钻头中轴线与校直中心线存在一定的角度,即钻杆的前进轨迹就会偏离理论值,或与地层干涉,或可能再次发生弯曲变形;另一主要原因是转向器滑道工作恶化。增加钻杆壁厚,降低工作压力和滑道摩擦因数,设计合理弯曲转向机构是解决问题的关键。     

忠武输气管道悬索跨越设计创新及探讨

忠武输气管道有4次悬索跨越,分别是蚂蝗溪悬索跨越、木龙河悬索跨越、马水河悬索跨越、野三河悬索跨越。文章介绍了这几座悬索跨越管桥设计中采用的多项新技术,如采用热聚乙烯半平行钢丝索代替以往的钢丝绳;采用钢管塔架代替以往的角钢塔架;根据地形地貌特点变换风索型式或取消塔架等。这些新技术、新设计在工程中均取得了良好的效果。另外,文章还针对悬索跨越桥面结构型式、预拱度设置、不对称荷载的影响、风索基础的设置等问题进行了探讨。     

Protecting local access telecommunications networks: Toward a minimum-cost solution

The problem of designing fibre-optic networks for local-access telecommunications generates (at least) three non-trivial subproblems. In the first of these subproblems one must determine how many fibre-optic cables (fibres) are required at either end of a street. In the next subproblem a minimum-cost network must be designed to support the fibres. The network must also provide distinct paths from either end of the street to the central exchange(s). Finally, the fibre-optic cables must be placed in protective covers. These covers are available in a number of different sizes, allowing some flexibility when covering each section of the network. In this paper we describe a dynamic programming (DP) formulation for finding a minimum-cost (protective) covering for the network (the third of the subproblems). This problem is a generalised set covering problem with side constraints and is further complicated by the introduction of fixed and variable welding costs. The DP formulation selects covers along each arc (in the network), but cannot exactly model the fixed costs and so does not guarantee optimality. We also describe an integer programming (IP) formulation for assessing the quality of the DP solutions. The cost of the networks constructed by the IP model is less than those designed using the DP model, but the saving is not significant for the problems examined (less than 0.1%). This indicates that the DP model will generally give very good solutions. Furthermore, as the problem dimensions grow, DP gives significantly better solution times than IP.     

基于Matlab的雷达试验数据分析处理系统

针对雷达外场试验中的需求,提出了基于Matlab软件平台的数据分析处理系统。该系统能很好地完成雷达录取数据的精度分析、威力分析和各种显示图形的绘制,并且在实际中得到了应用。     

微型轴流风扇噪声特性分析及试验研究

本文对微型轴流风扇噪声的产生机理进行了系统分析及教育处，并进行了实验测试。得出的分析计算结果与实验数据作了比较验证，在声压随观测角度和距离的变化关系上，两者显示出基本一致的趋势。文中以等流量为前提，对降低微型风扇噪声的一种途径作了计算，结果表明采用转轴很细的风扇，可使噪声明显降低（大于3dB）。     

A Bluetooth Based Sensor Network for Civil Infrastructure Health Monitoring

Communicating with sensors has long been limited either to wired connections or to proprietary wireless communication protocols. Using a ubiquitous and inexpensive wireless communication technology to create Sensor Area Networks (SANs) will accelerate the extensive deployment of sensor technology. Bluetooth, an emerging, worldwide standard for inexpensive, local wireless communication is a viable choice for SANs because of its inherent support for some of the important requirements – low power, small form factor, low cost and sufficient communication range. In this paper we outline an approach, centered on the Bluetooth technology, to support a sensor network composed of fixed wireless sensors for health monitoring of highways, bridges and other civil infrastructures. We present a topology formation scheme that not only takes into account the traffic generated by different sensors but also the associated link strengths, buffer capacities and energy availability. The algorithm makes no particular assumptions as to the placement of nodes, and not all nodes need to be in radio proximity of each other. The output is a tree shaped scatternet rooted at the sensor hub (data logger) that is balanced in terms of traffic carried on each of the links. We also analyze the scheduling, routing and healing aspects of the resulting sensor-net topology.     

宝珠寺重力坝安全监测设计及优化研究

大坝安全监测设计指导和控制着安全监测工作的进行，安全监测的效果和作用与监测设计质量有很大关系。通过对宝珠寺大级安全监测设计结果的研究，提出变形监测采用分段连续引张线法；渗流监测方面，测压管管径应小于50mm，且应根据不同测点量程，选用不同规格的仪器，以保证精度；应力监测有必要结合地质情况对监测设计进行优化；还应选择可能存在安全隐患和异常部位的测点进行自动化跟踪监测。     

水利项目评价指标赋权模型的建立及其应用

提出了用于水利项目方案评价的方法——基于相对最优方案的指标赋权模型,介绍了该方法的基本原理,建立了综合考虑保证出力、年发电量、单位千瓦投资等因素的基于相对最佳方案的指标赋权模型,并用实例加以说明,与模糊优选神经网络模型的评价结果相对比,研究表明该模型适合于水利项目方案的评价和优选。     

浅谈东深供水改造工程的设计监理工作

施工图阶段设计监理工作的内容归纳起来主要是对设计质量进行控制.依据<水利建设工程招标、施工图阶段设计监理试行规定>,其具体工作内容仅限于设计成果的合法性和安全性,没有充分发挥设计监理作用,对施工图阶段设计质量的理解是不全面的.施工图阶段的设计质量不仅仅是提交合法和安全的图纸,而且图纸的提交时限性、可实施性及经济性也应是考核设计质量的重要组成部分,为此东深供水改造工程的设计监理工作内容确定为"五项控制"和"两项权利",全面地对施工图阶段的设计质量进行控制.