基于VxWorks的实时多任务程序设计机制分析

实时多任务程序设计是嵌入式系统软件设计的基础.随着嵌入式系统性能的提高和功能的复杂,实时多任务程序设计会越来越复杂.简要介绍VxWorks下实时多任务程序设计机制,通过一个利用实时多任务来实现的通讯模型,重点介绍VxWorks下实时多任务程序设计的关键技术.     

嵌入式技术在铁路客运信息化领域的应用

根据铁路客运信息化的现状,阐述嵌入式技术的优点,介绍其在铁路客运信息化中的应用现状和前景,并介绍拥有中国自主知识产权的硬件平台、OS平台和GUI构造的嵌入式平台.     

Dynamics of an ultra-deepwater mooring line with embedded chain segment

A code is developed to study the mooring tensions on a line with an embedded segment considered, based on lumped mass method. The accuracy of this code is validated by published results. The influence of soil-chain interaction on the static and dynamic behaviour of a 1500 m mooring line is studied under two operational situations: shallow embedded taut mooring line and deep embedded semi-taut mooring line. The shallow case has an embedded depth setting as 10 m under seafloor, while the embedded depth is 20 m for deep water. To study the influence of soil on mooring dynamics, three simplified cases without soil force considered are investigated and the results are compared with the dynamics of embedded mooring. These three cases include: i) Case MA has the same spread distance to embedded mooring anchored on seafloor; ii) Case MB is anchored on seafloor and it has the same pretension with embedded mooring; iii) Case MC is anchored to the same point to the embedded mooring but the soil force is not considered. Furthermore, the effects of effective width parameters of tangential and bearing soil resistance on mooring dynamics are also discussed. In this work, three different oscillations are forced on fairlead to study the mooring dynamics, which are low frequency oscillation, hybrid oscillation (low frequency and wave frequency) and wave frequency oscillation.     

汽车灯具中灯体嵌件后压入工艺研究

介绍了汽车灯具中灯体嵌件后压入工艺中冷、热2种压入方式的工艺过程及特点,给出了灯体后压入嵌件和底孔的尺寸及设计方法.试验结果表明,与嵌件直接注塑嵌入成型相比,嵌件后压入工艺具有模具结构简单、灯体报废少、嵌件定位精度准确等优点,可保证灯体加工和装配的质量要求.     

燕塞湖桥斜拉索锚固区预埋管角度修正计算

以一座四跨(72m 120m 120m 72m)预应力混凝土部分斜拉桥为工程背景,介绍斜拉索锚固区预埋管角度修正的计算.     

嵌入式系统的设计与开发

随着计算技术、通信技术的飞速发展,特别是互联网的迅速普及和3C(计算机、通信、消费电子)合一的加速,微型化和企业化成为发展的新趋势,嵌入式产品成为新的亮点。嵌入式系统就是先进的计算初技术、半导体技术、电子技术以及各种具体应用相结合的产物,是技术密集、资金密集、高度分散、不断创新的新型集成知识系统。本文介绍了嵌入式系统的基本知识,提出了在嵌入式系统开发过程中应遵循的原则,并结合实例进行了分析。     

基于NiosⅡ的数据采集系统设计与实现

介绍主要以EP1C6Q240C8与TLC548为硬件平台的数据采集系统的设计与实现方案,重点阐述了嵌入式系统NiosⅡ系统的构成及配置,以及硬件平台设计与实现。最后测试证明此数据采集系统能够很好地实现8路AD数据采集及与上位机通信,达到较高的精度和较高的稳定性。     

Three Dimensional Numerical Simulation Study on the Tensile Test of the Embedded Components in Segment Joints of Deep Buried Storage and Drainage Shield Tunnels北大核心CSCD

The numerical simulation was carried out based on tensile test of the embedded components in segment joints of the deep buried storage and drainage shield-driven tunnel in Shanghai in order to study the numerical approach for mechanical analysis of segment joints of the tunnel. Using the concrete damage plasticity model and nonlinear springs, the 3D refined numerical model was established, in which the embedded components with complex geometries and the bond-slip behaviors between the concrete and bars were taken into consideration. Three kinds of embedded component models with different degrees of refinement were established and simply loaded. By comparing the calculation results and considering the spent time and the accuracy of calculation, the simplified form of the embedded components used in the overall model was determined. Nonlinear springs between anchor bars and concrete were set in the model in order to simulate the bond-slip behavior between them. In addition, two contrast models were also established using binding constraint and face-face contact constraint between concrete and anchor bars respectively. The three types of models were loaded in accordance with the test conditions. Comparing the results of the numerical calculation with the test results, it is shown that the "nonlinear spring model", which takes the bond-slip behavior into consideration, is more consistent with the test results than the "face to face contact model" and "binding model". And the model also reflects the failure mode very well. It indicates that the three dimensional refined modeling method used in this paper is applicable for similar tensile tests. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Can high speed rail offset its embedded emissions?

This paper analyzes the climate implications of investments in high speed railway lines given uncertainty in future transport demand, technology and power production. To capture the uncertainty of estimated parameters, distributions for the annual traffic emissions reduction required to compensate for the embedded emissions from the construction of infrastructure are calculated using Monte Carlo simulation. In order to balance the annualized emissions from the railway construction, traffic volumes of more than 10 million annual one-way trips are usually required. Most of the traffic diverted from other modes must come from aviation and the project cannot involve the extensive use of tunnels.     

基于嵌入式列车油量远程监控系统设计

针对列车油量监测中多点信息采集以及实时传送的要求,提出了基于嵌入式操作系统和GPRS的新型列车油量监控系统,实现数据远程、快捷及低成本的传输。介绍了系统功能、硬件组成原理及软件设计方案,并结合实时数据和曲线图对终端试运行情况作了说明。通过上车试运行,结果表明该系统对于控制、降低列车的油量消耗具有重要的量化指导意义。