美军军事通信卫星发展趋势分析及启示

文章讨论了美军先进的军事卫星通信系统,分析归纳了美军卫星通信的特点与发展趋势,并针对我国军事通信卫星发展现状阐述了需要解决的关键技术问题及发展思路。     

基于生产函数的长江航道对长江经济带的科技贡献度测算

为明确长江航道对长江经济带的科技贡献作用,运用扩展的柯布-道格拉斯生产函数模型定量计算长江航道对长江经济带的科技贡献度。结果表明,2005-2017年长江航道科技对长江经济带的平均贡献度为38.31%,整体水平较高,科技进步对长江经济带的发展拉动作用明显。     

四层PCB板中20 H规则的辐射分析

针对业界广泛讨论的20 H规则边缘辐射进行仿真分析.采取基于腔模理论,对四层PCB板场的理论分析,建立了以微带天线为结构的模型,并进行了模型理论分析与仿真对比验证.仿真结果表明:20 H规则在四层PCB板中的应用是不能达到减少边缘辐射效果的.     

轻便触探锤击数N10与静力触探锥端阻力Qc的关系

根据公路桥、涵台背回填中粗砂密实度检测的室内模型试验，探讨了轻便触探试验数据与静力触探试验数据之间的关系，并建立了轻便触探锤击数N10与静力触探锥端阻力Qc之间的相关关系式，验证表明轻便触探与静力触探具有较好的相关性。     

遂渝线无砟轨道综合试验段低净空隧道接触悬挂方案与施工

研究目的:介绍和探讨遂渝线无砟轨道综合试验段中出现的低净空隧道的接触悬挂方式,并针对类似的低净空隧道的处理提出了一些可靠、可行的方案.通过对遂渝线无砟轨道综合试验段中出现的低净空隧道的接触悬挂方式的介绍和探讨,对于类似的低净空隧道的处理提出了一些可靠,可行的方案.研究结论:解决低净空问题的关键所在是如何利用既有隧道的净空高度和尽可能地保证各种技术标准;其次是要对材料的节约和造价等方面进行考虑.对于不同情况下的低净空隧道有不同的解决方案和优势,这需要视现场情况而定.     

浅析Web2.0环境下的图书馆信息服务

本文尝试从Web2.0的概念与特点以及常用技术出发,浅析Web2.0环境下各项先进技术对图书馆信息服务的影响,丰富信息服务手段,提高服务质量。     

6×2型载货汽车随动桥轮胎磨损分析及对策

由基本车型而派生出的带随动桥结构的６×２型载货车形式，普遍存在随动桥轮胎磨损严重的毛病，这势必增加了汽车的使用成本，还必然会导致汽车在行驶过程中的功率损耗增加和车轮与地面间附着情况的恶化，进而制约汽车各种性能的正常发挥，本提出了结构上的可能的改进途径，为此类结构的整车设计提供了设计依据。     

锚索抗滑桩设计中的几个问题探讨

对锚索抗滑桩设计中的合理间距、桩的嵌固深度、抗滑桩内力和变形计算等问题进行了探讨。指出对于锚索抗滑桩系统来说,最小间距应根据桩和锚索的间距综合考虑;对于锚索抗滑桩的嵌固深度,只要使其满足桩周地基承载力的要求即可,仅靠增加桩的嵌固深度,对改善桩身内力和变位的意义并不大。分析了当前计算锚索抗滑桩内力和变形的几种主要方法,讨论了影响锚索抗滑桩内力和变形分布形式的主要因素以及对锚索抗滑桩进行全局优化设计的思路。     

Validating the results of a route choice simulator

This paper describes the validation of a route choice simulator known as VLADIMIR (Variable Legend Assessment Device for Interactive Measurement of Individual Route choice). VLADIMIR is an interactive computer-based tool designed to study drivers’ route choice behaviour. It has been extensively used to obtain data on route choice in the presence of information sources such as Variable Message Signs or In-Car Navigation devices. The simulator uses a sequence of digitized photographs to portray a real network with junctions, links, landmarks and road signs. Subject drivers are invited to make journeys between specified origins and destinations under a range of travel scenarios, during which the simulator automatically records their route choices. This paper describes validation experiments carried out during the period Summer 1994 to Autumn 1995 and reports on the results obtained. Each experiment involved a comparison of routes selected in real life with those driven under simulated conditions in VLADIMIR. The analysis included investigation of the subjects’ own assessment of the realism of the VLADIMIR routes they had chosen, a comparison of models based on the real life routes with models based on VLADIMIR routes, and a statistical comparison of the two sets of routes. After an extensive series of data collection exercises and analyses, we have concluded that a well designed simulator is able to replicate real life route choices with a very high degree of detail and accuracy. Not only was VLADIMIR able to precisely replicate the route choices of drivers who were familiar with the network but it also appears capable of representing the kind of errors made and route choice strategies adopted by less familiar drivers. Furthermore, evidence is presented to suggest that it can accurately replicate route choice responses to roadside VMS information.     

建立符合社会主义市场经济的建设工程计价模式的探讨

为适应社会主义市场经济的需要 ,对建设工程计价模式提出若干改进意见