考虑服务交通量的加速车道长度设置方法

高速公路加速车道的设置长度不仅取决于主路及匝道的设计速度,还与主路及匝道的交通量有关。本文给出了不同主路服务交通量下的匝道通行能力,建立了在主路不同交通负荷下的匝道车辆可直接汇入的概率计算模型。最后给出了在一定的匝道车辆汇入概率和主路服务交通量下的加速车道长度设置方法,以及不同主路、匝道设计速度和服务交通量下的加速车道长度的推荐值。     

压力管道工程焊接技术与质量控制

焊接技术是压力管道质量控制的核心技术。介绍了压力管道的焊接工艺、如何提高生产率、降低焊接成本以及使焊接质量可靠、焊缝成形美观 ,提出了焊接质量控制的方法和要求     

东江特大桥主航道桥方案设计

东江特大桥主航道桥投标方案设计为 1 60 m+80 m独塔单索面斜拉桥。主跨加劲梁为钢箱梁 ,边跨加劲梁为预应力混凝土箱梁。该桥结构设计合理 ,造型轻巧美观 ,在节省材料、缩短工期方面具有优越性。本文主要介绍东江特大桥桥型总体设计 ,包括自然条件、结构设计、结构计算及施工要点     

柴油机排气微粒捕集器燃气再生可行性研究

提出了一种新的柴油机排气微粒捕集器的再生技术 ,即利用燃气与排气中的O2 燃烧清除微粒捕集器中沉积的微粒 (PM)。根据燃气的物化特性和排气中的含O2 量 ,对这种方法的可行性进行了理论分析和试验验证 ,为解决柴油机PM排放控制提供了一条新的技术途径     

论多塔斜拉桥的刚度

以武汉阳逻长江公路大桥三塔斜拉桥方案静力性能分析为例，对多塔斜拉桥提高刚度的措施进行了分析和比较。     

某大桥桥塔裂缝成因分析

以某大桥桥塔裂缝为背景从裂缝的特征，材料特性，结构特点和环境条件及变化的综合分析判断裂缝成因，并通过分析计算解释开裂现象。     

空气动力制动风翼在车上布置数值仿真研究

采用流体仿真分析软件FLUENT研究制动风翼尾迹的影响范围及制动风翼纵向间距对制动效果的影响,同时分析制动风翼不同横向间距对制动阻力影响的规律.结果表明:2幅制动风翼的纵向间距越大.列车前部制动风翼对后部制动风翼的尾迹影响越小,当2幅制动风翼的纵向间距超过2节车厢长度时,这种影响完全消失;在制动风翼面积相同的条件下,增大每幅2片制动风翼的横向间距,能够提高风翼的单位面积制动阻力;由制动风翼产生的制动瞬时减速度随制动初速度的增加而增加,在紧急制动初速度为500km>h-1时由制动风翼产生的制动合阻力约为160kN.此时的制动瞬时减速度约为0.33m.s-1,可知,列车高速运行时由空气动力制动产生的制动阻力对高速列车制动贡献很大,空气动力制动在高速时具有优良制动性能.     

高速公路岩堆边坡仿真分析与评价研究

在分析宜巴高速公路三里花岩堆边坡基本特征及破坏机理的基础上,基于FLAC3D理论,建立了山区高速公路岩堆边坡三维仿真分析模型,在此基础上,考虑岩堆天然自重、降雨、地震和人类活动等荷载组合作用,模拟分析了岩堆边坡在不同工况条件下的变形破坏机理和稳定性,并对岩堆边坡的稳定状态进行了评价.     

The role of geomatics engineering in establishing the marine information system for maritime management

Maritime management encompasses the employment and manipulation of human resources, financial resources, technological resources and natural resources that relate to the sea, maritime navigation, shipping, port development and coastal protection. It contributes to the economic growth, price stability, transportation of cargoes and passengers, and business activities of shipping organizations. The efficient management of resources, operations and activities relies on a modern marine information system (MIS) whose information is provided by geomatics engineers and IT professionals, among others. This paper first introduces the role of the geomatics engineer as geodesist, engineering surveyor, land boundary surveyor, cartographer, hydrographer, photogrammetrist and geographic information system (GIS) engineer since all these fields are related to maritime trade, supply chains and development of ports and airports. It then describes the principal components of a web-based MIS and the important role of geomatics engineers in surveying data. This includes collecting data from electronic nautical charts (ENC) and raster nautical charts (RNC), by applying high resolution light detection and ranging (LIDAR), satellite platform sensors and GIS.     

Experimental investigation of wing-in-ground effect with a NACA6409 section

The aerodynamic characteristics of NACA6409 in the vicinity of the ground were experimentally studied in a wind tunnel. Lift and drag forces, the pitching moment, and the center of pressure were measured with respect to various major aerodynamic parameters, such as the ground clearance, the angle of attack, the aspect ratio (AR), and the endplate type, which resulted in a total number of 420 conditions. In addition, a smoke trace test was conducted to visualize the flow pattern around NACA6409 in the vicinity of the ground. As a result of the ground effect and the influence of the endplate, the lift-to-drag ratio increased at low ground clearance and the center of pressure moved forward to the leading edge; that is, the endplate and ground effects were equivalent to the aerodynamic advantage that results from increasing the AR of the wing. Extended experimental results are useful for understanding the aerodynamic characteristics influenced by each aerodynamic parameter during ground effect as well as for verifying numerical simulation.