基于理想解法的相控阵雷达系统效能评估方法

根据武器系统效能评估定义,为了减少相控阵雷达系统效能评估中权重设置人为因素的影响,提高评估的客观性,在给出评估指标的基础上,引入熵权理想解法对指标权重进行求解,并对系统进行评估。最后,通过与其它方法进行比较,验证了文章方法的合理性。     

风机塔架与叶片相互作用的数值模拟(英文)

Numerical simulations of wind turbine blade-tower interaction by using the open source OpenFOAM tools coupled with arbitrary mesh interface(AMI) method were presented.The governing equations were the unsteady Reynolds-averaged Navier-Stokes(RANS) which were solved by the pimpleDyMFoam solver,and the AMI method was employed to handle mesh movements.The National Renewable Energy Laboratory(NREL) phase VI wind turbine in upwind configuration was selected for numerical tests with different incoming wind speeds(5,10,15,and 25 m/s) at a fixed blade pitch and constant rotational speed.Detailed numerical results of vortex structure,time histories of thrust,and pressure distribution on the blade and tower were presented.The findings show that the wind turbine tower has little effect on the whole aerodynamic performance of an upwind wind turbine,while the rotating rotor will induce an obvious cyclic drop in the front pressure of the tower.Also,strong interaction of blade tip vortices with separation from the tower was observed.     

老庄隧道设计施工优化的探讨

隧道施工是个动态过程,掌子面前方的围岩经常变化。为了配合施工及确保隧道结构的安全稳定,常常会发生隧道设计变更。利用FLAC3D数值计算软件对老庄隧道设计变更进行了计算,以分析隧道结构的稳定性,对隧道设计和施工有一定的借鉴意义。     

淤泥质软土固化理论研究及进展

淤泥属特殊土,具有不同于一般土的特性,其处理难点是高含水率和有机质。淤泥固化处理涉及到岩土工程、环境工程、土壤学、材料化学等相关学科。从固化材料、固化机理、固化土性能方面总结了国内外研究进展后,提出淤泥固化需要解决的问题:淤泥固化处理须与土壤学联系起来;固化材料的基础研究;有机质含量与固化材料、固化土性能的定量研究;固化土耐久性研究;施工工艺、设备等方面的进一步研究。     

某市公路箱涵施工试验阶段周边地表变形监测与分析

针对某市区箱涵施工,采用现场监测的手段,跟踪监测公路箱涵施工试验段周边地表变形的发展过程。通过分析监测数据,得出施工试验段周边地表的沉降、水平位移变形,主要集中在开挖基坑、钢板桩施工、开挖至底部和拔除钢板桩四个施工阶段,且拔除钢板桩时变形最大。通过对检测数据的分析:试验段的累计地表沉降、累计水平位移和裂缝变形等几个主要控制指标,均超过设计预警值,故原设计方案需进一步改进。     

回收废料用于沥青道路铺筑的研究与展望

道路铺筑和养护要消耗大量的集料和矿粉,回收料的替代使用有助于保护节约天然资源。结合沥青混合料和集料的各种路用指标,对各类可用作沥青道路铺筑的回收废料进行研究,其中包括钢渣、玻璃、塑料、橡胶、水泥、陶瓷等工业、建筑废料以及生活垃圾焚烧灰等。根据回收料的颗粒大小、硬度、粗糙度、孔隙率、弹性等特性,将它们分别用于道路各个层面结构中,其体现出与天然集料和矿粉相同甚至更优越的路用性能。     

信号灯平交路口优化设计方法

平交路口通行能力,一直是城市交通设计与管理者关注的重点。对于拥堵平交路口的改造,往往依赖于对路口宽度及通行时间上的增加,来实现平交路口整体通行能力的提升,而忽视了路口设计通行能力与实际交通量的匹配。通过实际案例,阐述在不增加路口宽度及信号灯周期条件下,通过对路口渠化车道及信号灯配时的调整,提高路口通行能力的设计方法,可为信号灯路口的优化设计提供一些借鉴和思路。     

交流励磁电机转子电势相位检测器

采用增量式旋转脉冲编码器,设计了一种交流励磁电机转子电势的相位检测器,以所检测到的转子电势相位作为进行矢量控制的参考,从而获得对转矩和功率因数分别控制的优良调速性能。     

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基于对左转专用车道停车线的研究,分析了停车线的位置与相位绿灯间隔时间和车道饱和流量这两个交叉口通行能力关键影响因素的关系在保障交又口车辆通行安全的前提下,以交叉口通行能力最大为目标,建立以左转车道停车线位置与直行车道停车线位置之间距离为基本参数的数学模型,并提出了相应的解法,最后,通过具体的交又口实例分析,求解出了左转停车线的最佳位置,证明该模型具有很好的实用性.     

Using a stages of change approach to explore opportunities for increasing bicycle commuting

Given the potential benefits of bicycling to the environment, the economy, and public health, many U.S. cities have set ambitious goals for increasing the bicycle share of commute trips. The Transtheoretical Model of Behavior Change, which seeks to describe how positive and permanent change can be fostered in individuals, may shed light on how cities can most effectively increase bicycle commuting. We use the model’s “stages of change” framework to explore the potential for increased bicycle commuting to the UC Davis campus in Davis, California. Our analysis uses data from the 2012 to 2013 UC Davis Campus Travel Survey, an annual online survey that is randomly administered to students and employees at UC Davis. Based on their responses to questions about current commute mode and contemplation of bicycle commuting, respondents are divided into five stages of change: Pre-contemplation, Contemplation, Preparation, Action, and Maintenance. We construct a Bayesian multilevel ordinal logistic regression model to understand how differences in socio-demographic characteristics, travel attributes, and travel attitudes between individuals explain their membership in different stages of change. In addition, we use this model to explore the potential of various intervention strategies to move individuals through the stages of change toward becoming regular bicycle commuters. Our results indicate that travel attitudes matter more to progression toward regular commute bicycling than travel attributes, tentatively supporting the efficacy of “soft” policies focused on changing travel attitudes.