非结构化网格在印尼亚齐电厂温排水模型中的应用研究

印尼亚齐(ACEH)电厂取水口温升是判断工程平面布置方案优劣的关键。应用局部加密的非结构化网格建立了平面二维潮流温排水数学模型。该模型能很好地描述复杂地形,既保证了工程区域水动力计算精度,也减少了计算量。在水动力计算过程中考虑了洋流和季风等长周期动力因素,研究了温排水在这种长周期动力条件下的扩散规律。计算了不同布置方案条件下温排水的影响范围,对不同布置方案进行了评价。     

基于维特比算法的卷积码译码器设计

卷积码的状态转移规律可以用网格图来描述,网格图是一种能清楚显示状态转移的时间依赖性状态图。文章在介绍卷积码原理的基础上,对维特比译码实现过程中的状态网格图的规律进行了深入研究,采用了状态路径度量的＂加、比、选＂运算方法、保存路径转移的回溯译码方法等,有效的提高整个卷积码译码器的性能。最后进行了编程仿真,结果显示维特比译码的效果比较理想,满足了设计的要求。     

基于B样条的船体网格划分及水动力计算

基于B样条理论的特点,提出一种高效的船体水动力网格划分方法,开发相应的程序。将此方法直接应用于某50万t矿砂船的三维线性频域水动力计算中,将计算结果与文献结果进行对比分析,其结果与相关文献结果非常吻合,认为用B样条方法进行船体水动力网格划分是可行。     

A RANS-based technique for simulation of the flow near a rolling cylinder at the free surface

Accurate prediction of roll motion is very important in ship dynamics, particularly when the safety of the ship is in question. In this paper "COMET," a Reynolds averaged Navier–Stokes (RANS) solver, is used to simulate the flow in the vicinity of a rectangular cylinder rolling at the free surface and to demonstrate the potential of RANS-based techniques in complex flows with free surfaces. The method adopted is based on an unstructured collocated finite-volume technique, which uses a variation of the SIMPLE scheme for pressure correction. An advanced interface capturing technique known as high resolution interface capturing (HRIC) is used for tracking the free surface with reduced numerical diffusion. The results derived are compared with available numerical and experimental results, showing good agreement on added moment of inertia and damping coefficients, whilst accurately predicting other main features of the flow. However, further validation for other geometries and extension to 3-D hull forms are essential before applications to practical problems are realised. Received: January 26, 2000 / Accepted: October 2, 2000     

北京市沥青路面道路大修中几个问题的探讨

为迎接奥运会,北京市近几年进行了大规模的道路大修工作。该文归纳了道路大修的特点,从道路大修工程实例入手,阐述了北京市沥青路面道路大修中存在的若干问题,针对存在的问题,提出了相应观点或建议。     

广汕路模块挡土墙的设计

由于高挡土墙对地基的承载力要求较高,而且尺寸较为庞大,在城市内还须满足占地和景观的要求。因此在城市内修建挡土墙,具有一定的难度,而采用模块挡土墙可以较好的满足各方面的要求。该文的总结及介绍,可为类似工程参考和借鉴。     

基于Web服务的网格服务研究

介绍了Web服务和网格服务的理论．分析Web服务机制,并根据OGSA结构对网格服务的特点进行描述．从而建立了基于Web服务的网格服务的模型,并将该模型应用到旅游服务中．     

网格计算和信息共享

从网格技术提出的背景和其优越性出发,分析其协议体系结构及其各个协议之间的关系.详细介绍目前最为流行的开放网格服务体系结构OGSA的实现环境和接口机制,并且以一个基于OGSA的数据挖掘应用例子说明在多级虚拟网络运行环境下,网格服务是如何解决在从多个信息源集成信息过程中的远程接口激活,生命周期管理,通知和授权等功能的实现问题.这也是广域网环境下大型分布式系统中普遍存在的技术难点.     

信息数据库网格技术研究

首先对信息数据库网格系统进行了简单介绍,对以XML技术为基础的异构数据集成问题进行了研究;其次时信息数据库网格的网络拓扑结构进行了分析;最后给出了信息数据库网格的总体设计架构并对总体架构中的组成部分进行了分析.     

Impacts of replacement of engine powered vehicles by electric vehicles on energy consumption and CO2 emissions

This paper evaluates the impacts on energy consumption and carbon dioxide (CO₂) emissions from the introduction of electric vehicles into a smart grid, as a case study. The AVL Cruise software was used to simulate two vehicles, one electric and the other engine-powered, both operating under the New European Driving Cycle (NEDC), in order to calculate carbon dioxide (CO₂) emissions, fuel consumption and energy efficiency. Available carbon dioxide data from electric power generation in Brazil were used for comparison with the simulated results. In addition, scenarios of gradual introduction of electric vehicles in a taxi fleet operating with a smart grid system in Sete Lagoas city, MG, Brazil, were made to evaluate their impacts. The results demonstrate that CO₂ emissions from the electric vehicle fleet can be from 10 to 26 times lower than that of the engine-powered vehicle fleet. In addition, the scenarios indicate that even with high factors of CO₂ emissions from energy generation, significant reductions of annual emissions are obtained with the introduction of electric vehicles in the fleet.