地铁车站建筑防火及安全疏散设计

通过车站建筑防火分区及防火墙设置、防烟分区、安全疏散三个方面详细的阐述了地铁车站建筑防火及安全疏散设计,旨在为地铁车站建筑设计提供借鉴.     

南京南站综合枢纽道路集疏运系统规划设计

为了使南京南站达到高效便捷、快速集散,提高道路交通对综合枢纽的保障能力,进行道路集疏运系统规划设计是必要的。该文根据南京南站的区位特征和功能定位,结合交通需求分析,按照"以人为本、公交优先、同向进出、全面对接"的规划理念,提出了南京南站综合枢纽道路集疏运系统的规划设计方案以及交通组织设计,包括快速环线工程、高架联络道工程,为国内大型客运枢纽的规划设计提供参考。     

确定OD矩阵和路段选择率的方法

OD矩阵推算和交通分配的结果是否符合实际,受所用分配模型、分配率P是否符合实际、路段流量是否经过守恒处理等因素影响。不同的分配参数会对分配率P产生不同的影响,从而影响分配结果,最终影响反推。采用对路段选择率和OD量同时推算的方法,尽量避免由于取值问题带来的误差,从而使推算结果更符合实际。     

Simulations of pollutant dispersion at toll plazas using three-dimensional CFD models

Toll plazas are particularly susceptible to build-ups of vehicle-emitted pollutants because vehicles pass through in low gear. To look at this, three-dimensional computational fluid dynamics simulations of pollutant dispersion are used on the standard k − ε turbulence model. The effects of wind speed, wind direction and topography on pollutant dispersion were discussed. The Wuzhuang toll plaza on the Hefei-Nanjing expressway is considered, and the effects of the retaining walls along both sides of the plaza on pollutant dispersion is analysed. There are greater pollutant concentrations near the tollbooths as the angle between the direction of the wind and traffic increases implying that retaining walls impede dispersion. The slope of the walls has little influence on the variations in pollutant concentration.     

Computer simulation of impacts of a chlorine tanker truck accident

The aim of the study was to present the author’s original modelling programs of pollution dispersion in an urban environment. The programs outlined herein are based on a diagnostic model of air velocity field and Langrangian particle model. In both modelling programs author’s elements of mathematical modelling were applied. The models have been validated and verified. Geographic Information System (GIS) Idrisi Andes was applied in the pre-processing stage.The development of author’s original computer program and stages of hazardous material propagation modelling were discussed.The results of computations and analysis of pollution dispersion caused by a chlorine tanker truck collision and chlorine release into atmosphere were presented. It was simulated that the accident took place in the city of Bielsko-Biała, on a bypass in a built-up area causing leakage of 10 t of chlorine. The computer simulations conducted for two wind direction scenarios allow to conclude that the total area affected by the pollutant cloud with concentrations above threshold levels could be over 2 km², with 5000 lethally exposed people.     

QT离散度对急性心肌梗塞患者室性心律失常的预测价值

为探讨QT离散度的临床意义，分析了50例急性心肌梗定（Acutemyocrfailinfarction，AMI）患者心电图的QT离散度。结果发现，AMI1周内患者的QT离散度显著大于陈旧性心肌梗塞患者和健康人；并发心律失常的AMI患者的QT离散度大于无心律失常的AMI患者．提示QT离散度对掌握AMI患者病情及预后有重要指导意义。     

论OTN网络规划设计及在铁路中的应用

在简要分析OTN技术特点的基础上,探讨OTN网络规划设计流程,分析网络规划设计中的基本四要素,及OTN在铁路上的应用。     

关于OTN纠错前误码率随机波动问题的分析

根据光传输通信工程建设的实例,针对高速率光传输系统内Rn参考点纠错前误码率随机波动变化问题进行分析,阐述光缆偏振模色散对于该问题的影响,介绍具体的分析处理过程,并提出解决措施和建议。     

Characteristics of speed dispersion and its relationship to fundamental traffic flow parameters

Speed dispersion is essential for transportation research but inaccessible to certain sensors that simply record density, mean speed, and/or flow. An alternative is to relate speed dispersion with these available parameters. This paper is compiled from nearly a quarter million observations on an urban freeway and a resulting data-set with two speed dispersion measures and the three fundamental parameters. Data are examined individually by lane and aggregately by direction. The first dispersion measure, coefficient of variation of speed, is found to be exponential with density, negative exponential with mean speed, and two-phase linear to flow. These empirical relationships are proven to be general for a variety of coefficient ranges under the above function forms. The second measure, standard deviation of speed, does not present any simple relationships to the fundamental parameters, and its maximum occurs at around a half to two-thirds of the free flow speed. Speed dispersion may be significantly different by lane.