我国城市轨道交通用钢发展前景分析

城市轨道交通作为兼具绿色、高效、安全等特点的新式交通方式，是我国现代交通体系建设中的重要组成部分，正在蓬勃发展。在分析我国城市轨道交通发展现状的基础上，对城市轨道用钢的结构、品种进行了阐述，并结合行业技术发展对未来我国城市轨道交通用钢发展方向进行了说明。     

颗粒阻尼器在启动气压缩机的减振应用

通过对启动气压缩机两种激励源：惯性力和机械冲击进行动力学分析，分析引起压缩机振动的原因。利用颗粒阻尼的被动降噪技术，提出一种基于颗粒阻尼器的减振方案。将启动气压缩机机械结构分析和振动分析相结合，设计颗粒阻尼器结构形式，确定安装位置。在此基础上为海洋石油平台压缩机的减振措施进行进一步的探索。     

城市轨道交通机电安装技术探究

在城市轨道交通工程中,机电设备占据了重要地位,欲提升机电设备安装的质量,就要做好彼此间的协调处理工作,才能满足城市轨道交通的建设质量。分析城市轨道交通机电系统主要结构,探讨安装技术和施工质量控制措施,以为轨道交通安全运行提供必要的保障。     

“十五”期间滚动体技术的发展

轴承行业“十五”发展规划纲要确定了中国轴承行业总体发展目标，所确定的技术攻关任务主要有两个，一是提高轴承寿命与可靠性，二是滚子轴承减振降噪。对于滚动体行业，“十五”攻关的重点是围绕轴承攻关的两大任务，认真分析我国滚动体的制造水平和质量水平，针对影响轴承寿命振动噪声的主要因素，解决滚动体关键制造技术，与轴承制造企业紧密配合，全面提升滚动体的质量，实现滚子轴承减振降噪，提高轴承的寿命和可靠性。     

基于云计算的城市轨道交通信息化平台研究

随着云计算技术的成熟,城市轨道交通智能化已经成为其未来发展的重要方向。探究云计算与城市轨道交通运营的融合路径,研究城市轨道交通云计算平台的基础架构,特别关注了其计算资源架构,并从知识库和运行大数据分析两个角度为其灾备中心应急处置系统提供了两种故障处理思路,最后对于大型城市中心云计算模式的缺陷提供了边缘云计算思路,为城市轨道交通智能化发展提供借鉴与参考。     

新型道路复合沥青材料改性剂的选择与配比优化

为了优化沥青路面材料的减振降噪性能,延长路面的使用寿命,对现有沥青材料进行改性优化。选用硅藻土和玄武岩纤维作为改性剂对沥青材料进行复合改性,依据孔隙率、阻尼比、矿料间隙率、吸声系数、流值变形量、马歇尔稳定度、沥青饱和度7个参数确定复合改性沥青材料的配比,制备出硅藻土与玄武岩纤维复合改性沥青材料。分别对硅藻土单掺杂沥青材料、玄武岩纤维单掺杂沥青材料和硅藻土与玄武岩纤维复合改性沥青材料进行了力学特性试验,分析其物理性能,并对不同沥青混合料的减振降噪性能进行了对比测试。结果表明,硅藻土和玄武岩纤维复合掺杂最佳配比：油石质量比为5.5%,玄武岩纤维掺杂比为0.3%,硅藻土掺杂比为7.5%。复合材料的减振降噪性能优于普通沥青材料,与其相比,最优配比下的新型复合材料吸声系数峰值高出38.89%,吸声系数均值高出30.30%。复合改性沥青材料具有良好的减振降噪性能并且具有显著的高温稳定性和低温抗裂性,研究结果可为同质路面材料的进一步优化提供参考,对于提高道路的服务能力具有实际应用价值。     

小型电机轴承润滑油脂减振降噪性能与应用

针对小型电机常用的小型密封深沟球轴承,总结润滑油脂性能对其振动噪声的影响,并从减振降噪的目的出发,提出润滑油脂的选用原则及生产工艺改进措施。     

冷却塔生产环节中降噪节能设计分析

对机械通风冷却塔主要噪声的来源进行了分析,通过实例对降噪措施、节能运行等问题进行分析探讨,并提出了可行并有实际效果的降噪措施优化建议。     

开辟地铁施工新路径

城市轨道交通是一座城市融入国家大都市现代化交通的显著标志。它不仅是一个国家的国力和科技水平实力的展现,更是解决大都市交通紧张状况最理想的交通方式。北京、上海、广州等中心城市已形成城市轨道交通网络,其对城市整体发展地提升作用日益显现。在城市轨道交通施工领域,中国中铁隧道集团不断创新隧道施工方式,从首创浅埋暗挖法,到创造性推广世界先进的盾构技术,攻克了一系列地铁施工难题,创造了诸多施工记录。     

城市轨道交通车辆段检修设备维修措施

城市轨道交通是运输客流的主要力量,发展城市轨道交通能够有效缓解城市交通压力,而城市轨道交通的发展势必会给车辆的运维保障带来一定的挑战。阐述城市轨道交通车辆段检修设备的具体情况,并就不落轮镟床、列车自动清洗机设备、固定架车机3种检修设备的现行维修模式及优化后的维修模式进行研究,探讨车辆段检修设备管理情况,希望能够为完善地铁车辆配置和检修设备的安装提供参考。     

PPP模式在城市轨道交通领域的应用研究

分析PPP模式的主要特点及适用于城市轨道交通工程的制约因素与适用优势,提出了充分发挥市场化运作、完善运用PPP模式法规政策、深化PPP开发模式拓宽融资渠道、提升沿线综合开发土地价值4方面关键控制要点,对促进PPP模式深化转型与轨道交通建设适用性选择具有一定参考指导作用。     

城市轨道交通地下车站机电系统造价指标分析

随着经济和社会发展,我国城市轨道交通建设已进入快速发展阶段,如何有效控制投资成为制约轨道交通可持续发展的关键因素。本文结合城市轨道交通地下车站机电工程设计内容,以佛山某轨道交通线路为例,对地下车站机电工程的造价进行分析,得出不同车站机电工程经济指标,并找出影响车站机电工程造价的关键因素,为后续工程投资估算、设计概算编制及合理确定工程项目造价提供借鉴。     

一种基于机器视觉技术的城市轨道交通客流量检测方法

为了准确识别并检测城市轨道交通客流量变化,研究轨道交通客流量的变化规律,以客观图像为研究对象,以机器视觉技术为研究手段,提出了一种新的交通客流检测方法。在对交通客流视频图像进行滤波与增强后,利用Canny边缘帧差法从预处理图像中获取完整的运动目标轮廓。同时,利用AdaBoost检测算法构建的强分类器完成乘客头部的检测,并通过双线差值算法消除视频图像中不同位置尺寸所产生的误检框,实现对目标的跟踪与记载,完成客流量的统计。结果表明,该方法在交通客流量的检测中准确率高于90%。检测方法对提高城市轨道交通客流量的检测准确性具有一定的借鉴意义。     

The Value of Access to Rail Transit in a Congested City: Evidence from Housing Prices in Beijing

Using unique data sets of Beijing's congestion patterns and housing prices, I find that consumers are willing to pay significantly more for access to rail transit in more congested areas. Transit accessibility, however, offers little travel advantage outside of dense urban areas. The expansion of the metro network mitigates the costs of road congestion, creating both private and social benefits. Two policy initiatives aimed at reducing congestion are found to have achieved positive value effects. Further analysis reveals heterogeneous demand for accessibility, with wealthier residents and those owning fewer cars paying a higher premium for access to rail transit.     

基于长短期记忆网络的轨道交通短期OD客流量预测

为了更准确地掌握轨道交通客流在线网中的时空分布,更高效地匹配客流需求与运输能力,实现提高轨道交通运输效率、改善运营服务质量的目的,提出了一种基于长短期记忆网络的短期OD(交通起止点)客流量预测方法。以历史客流数据为基础,定性分析车站间OD客流量的时空相关性,利用回归分析法定量分析客流影响因素,筛选出运营时刻、运营日特征、最低气温3个时间特征。为提高预测精度,以长短期记忆网络为基础,结合时间特征,为每对起讫点单独构建预测模型,形成了基于长短期记忆网络的轨道交通短期OD客流量预测模型。以苏州市为例进行验证,结果表明,加入了时间特征的短期OD客流量预测模型较移动平均模型、仅利用历史客流数据训练的基于LSTM网络的短期OD客流量预测模型,预测结果与真实值之间的误差降低了6.27%～8.58%,所提出的方法和模型可为轨道交通运营部门制定列车运行计划、组织客运工作提供更准确的数据资料。     

The Impact of Urban Development on Auto Ownership and Transit Use

This study documents an investigation of how intermetropolitan differences in transit and highway service levels; as well as overall urban development patterns, affect auto ownership and use. Specifically, this paper presents models of the determinants of auto ownership and mode choice for 163,488 white, single-worker households residing in the largest 125 SMSAs in 1970. Indices of highway capicity, transit service levels, and overall residential density for each SMSA together with each household's socio-economic characteristics, workplace location, and residence choice, are used to explain each household's observed auto ownership status (0, one, or more than one car), and, given that auto ownership status, each household's worktrip mode (auto driver, auto passenger, bus, rail, or walk).
The models offer a framework for considering the effect of alternative urban development scenarios upon auto ownership and use, and for comparing alternative development and infrastructure policy options. Because the models have been estimated using households from different SMSAs, they are particularly appropriate for investigating changes in spatial structure.     

Redevelopment along arterial streets: The effects of light rail on land use change

We use difference-in-differences approaches and parcel-level data from Minneapolis to estimate the effects of light rail on land use change using alternate definitions of treatment area. Results using circular buffers corroborate previous findings that light rail has virtually no effect on land use change in our study area. In contrast, light rail increases the likelihood of land use change along arterial streets that cross the line at station areas. To accurately model the effects of public transit projects on urban land use, one must consider how potential riders access station areas, rather than assuming accessibility improves radially around a station.     

Hedonic Amenity Valuation and Housing Renovations

Hedonic and repeat sales estimators are commonly used to value such important urban amenities as schools, environmental quality and access to transit. Given that property data often omits information on quality differences between same‐aged homes as well as changes in structural attributes over time, researchers must assume that property renovations are uncorrelated with neighborhood amenities. We formally test if this assumption is valid by incorporating detailed data on renovations in Charlotte, North Carolina. We begin by testing how the inclusion of minor and major home improvements influences hedonic and repeat sales indices. Results find limited bias in hedonic indices and that renovated properties are no more likely to be sold than nonrenovated properties. Using the introduction of Charlotte's light rail‐transit system in 2000, we estimate a positive bias of between 1.6% and 19.9% on the capitalized benefits of access to light rail due to omitted information on renovations. Our results show that a number of common data cleaning techniques used to address missing information on structural improvements may worsen this bias.     

Gentrification Trends in New Transit-Oriented Communities: Evidence from 14 Cities That Expanded and Built Rail Transit Systems

Over 25 billion dollars were spent between 1970 and 2000 in 14 major cities in the United States on the construction of new rail transit lines. This massive investment in rail transit construction and expansion allows me to study the consequences of local public goods improvements for communities nearby new stations. This article uses a 14-city census tract–level panel data set covering the years 1970 to 2000 to document significant heterogeneity in the effects of rail transit expansions across the 14 cities. Communities receiving increased access to new "Walk and Ride" stations experience greater gentrification than communities that are now close to new "Park and Ride" stations.