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41.
李集  常乐 《隧道建设》2015,35(8):792-801
为实现岩溶突水风险评估的全过程动态修正与管理,一以岩溶发育分布规律为基础,采用半定量分析方法,估计溶洞与隧道在剖面图中的相对位置距离值,二将防突水岩层安全厚度的预测划分为初步估算、二次估计和动态测算3个阶段,每个阶段均采用有效的修正方式,不断获取更加准确且适用的防突岩层安全厚度预测数值。然后,综合考虑防突岩层安全厚度以及爆破开挖扰动深度影响,提出岩溶突水风险概率等级评价标准;通过划分突水量和溶腔高水头压强的等级,提出岩溶突水风险后果等级评价标准;并以二者为基础构建岩溶突水风险等级评估矩阵。最终,构建基于岩溶分布态势与防突岩层厚度的岩溶突水风险评估模型。通过具体工程实例检验,理论结果与实际情况相对比,验证所构建岩溶突水风险评估模型的合理性与可行性。  相似文献   
42.
应用P-5L_2型数字粉尘计与配有符合BMRC粒度分级标准予捕集器的粉尘采样器,置于各粉尘作业场,同时、同步测定呼吸性粉尘与总粉尘质量浓度及相对质量浓度,通过相关分析与计算,求得粉尘质量浓度转换K与K_1值,及CPM与mg/m~3换算图。  相似文献   
43.
This article examines the uncertainties concerning the antiturst immunity for collective participation by liner conferences in intermodal transporation. Among them are the FMC's jurisdiction under the Shipping Act to authorize such collective actions, the legality of intermodal dual-rate contracts and the stringency by lsquo;public-interestrsquo; justification. Administrative and judicial decisions proved ineffective in resolving the issues which legislative actions had, over a decade, failed to deal with. These uncertainties could soon be ended with passage of the maritime antiturst polity emerging out of this Congress. It is, however, still uncertain as to whether, and to what extent, the viabilty of the conference system would be threatened by the continued growth of intermodalism and vice versa. Congressional intent to safeguard the continued growth of intermodalism and the development of other future innovations means that these two issues are of more than just academic interests. Yet, they have not been adequately addressed in the policy studies currently available.  相似文献   
44.
Wu  Chenyang  Le Vine  Scott  Bengel  Elizabeth  Czerwinski  Jason  Polak  John 《Transportation》2022,49(2):641-678

In recent years, there has been a scholarly debate regarding the decrease in automobile-related mobility indicators (car ownership, driving license holding, VMT, etc.). Broadly speaking, two theories have been put forward to explain this trend: (1) economic factors whose impacts are well-understood in principle, but whose occurrence among young adults as a demographic sub-group had been overlooked, and (2) less well-understood shifts in cultural mores, values and sentiment towards the automobile. This second theory is devilishly difficult to study, due primarily to limitations in standard data resources such as the National Household Travel Survey and international peer datasets. In this study we first compiled a database of lyrics to popular music songs from 1956 to 2015 (defined by inclusion in the annual “top 40”), and subsequently identified references to automobiles within this corpus. We then evaluated whether there is support for theory #2 above within popular music, by looking at changes from the 1950s to the 2010s. We demonstrate that the frequency of references to automobility tended for many years to increase over time, however there has more recently been a decline after the late 2000s (decade). In terms of the sentiment of popular music lyrics that reference automobiles, our results are mixed as to whether the references are becoming increasingly positive or negative (machine analysis suggests increasing negativity, while human analysis did not find a significant association), however a consistent observation is that sentiment of automobile references have over time become more positive relative to sentiment of song lyrics overall. We also show that sentiment towards automobile references differs systematically by genre, e.g. automobile references within ‘Rock’ lyrics are in general more negative than similar references to cars in other music genres). The data generated on this project have been archived and made available open access for use by future researchers; details are in the full paper.

  相似文献   
45.
Daly  Andrew  Hess  Stephane 《Transportation》2020,47(3):1359-1364
Transportation - The value of travel time (VTT) can be said to be the most important number in transport economics, and its estimation has been the topic of extensive academic and applied work....  相似文献   
46.
Hess  Stephane  Daly  Andrew  Börjesson  Maria 《Transportation》2020,47(3):1541-1570
Transportation - Stated choice surveys have established themselves as the preferred approach for value of travel time elicitation with the help of choice models. However, major differences exist in...  相似文献   
47.
从高速动车组制动系统的设计原理出发,阐述了动车组制动系统故障诊断及安全措施的设计理念及实现方法:从设计的本质安全着手,考虑到各种可能出现的故障及其可能导致的后果的严重程度,设计对应的识别、判断及控制方法,系统自动或提示乘务人员处理故障或隔离故障设备、限速运行或者自动停车,从而确保列车的安全。本文介绍的故障诊断及安全措施的设计方法在我国高速动车组上得到了很好的验证。  相似文献   
48.
为提高长江电子航道图数据生产与数据管理的效率,开发基于.NET框架技术的长江电子航道图测量成果文件及产品文件管理、数据生产流程管理等功能的软件。在有效管理生产数据的同时,实现长江电子航道图数据生产的流程化管理,可为长江电子航道图数据生产提供有效的辅助。  相似文献   
49.
转向传感器信号是车辆控制系统的重要输入信号,但转向传感器的输出不是直接给出转向角大小而是方波信号。为了探究转向传感器原理以及Mazda6轿车实际转向过程中转向传感器信号,本文将介绍如何用simulink来识别该方波信号,输出转向角,最后用该方法识别出实际转向过程的转向角大小。  相似文献   
50.
针对当前复合制动系统再生制动力分配策略分析不全面的问题,基于复合制动系统结构形式和驾驶员制动意图的分类,对再生制动力分配方法进行了研究,并以装备前轴式复合制动系统的车辆为例进行了仿真分析.仿真结果表明,在紧急情况制动工况时再生制动力分配方法能够保证ECE法规所规定的稳定性要求.  相似文献   
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