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91.
Dongzi Zhu Hampden D. Kuhns John A. Gillies Vicken Etyemezian Scott Brown Alan W. Gertler 《Transportation Research Part D: Transport and Environment》2012,17(4):332-340
The effectiveness of control measures to reduce road dust emissions is analyzed using a year’s data of road dust emissions collected with a mobile sampling platform and a survey of road maintenance practices in the Lake Tahoe Basin of Nevada and California US. Attributes such as sweeping practices, anti-icing, shoulder improvement, pavement condition, trackout, and abrasive material from road segments were analyzed with a feature subset selection algorithm. Street sweeping was found to be an effective means of controlling dust emissions from roads. Road dust from dirty tertiary roads served as a continuous source of suspendable material for adjacent high-speed roads in the winter time. To be most effective, emission control strategies require that not only primary roads, but all roads be swept after snow storms to recover applied abrasive material. 相似文献
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为剖析家庭属性差异对大学生出行方式选择行为的影响,基于非集计理论,构建家庭属性差异的大学生出行选择多元Logit 模型. 根据四川省2 571 份大学生出行行为调查问卷,运用SPSS 软件标定模型参数,获取影响大学生出行选择的主要家庭属性因素,并进行敏感性分析. 结果表明:家庭平均年收入、经济净流对大学生出行方式选择有显著的影响;以航空运输为参考,家庭平均年收入、经济净流对公路运输方式选择的影响大于铁路运输;“祖辈替孙辈购买机票”的折扣票务形式可提高大学生选择航空出行的概率. 相似文献
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A novel type of control law was adopted to reduce the vertical acceleration of a fast ferry as well as the motion sickness incidence suffered by the passengers onboard by means of a submerged T-foil. Considering the system changing characteristics under high disturbances, a model-free approach was adopted. In addition, an upgraded proportional-derivative (PD) controller with correction terms resulting from a fast-online estimation of the system dynamics was designed. The overall controller, known as intelligent PD (i-PD) controller, was tested, and the obtained results were compared with those of a classic PD controller. The controllers were also tested in a changing environment and at different operating velocities. The results confirmed the effectiveness of the i-PD controller to smooth the motions with low computational cost control schemes. Furthermore, thanks to ability of the i-PD controller to continually update the estimated dynamics of the system, it showed a better reduction in both vertical motions and the seasickness level of the passengers with the needed robustness under external disturbances and system changing parameters. 相似文献
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朱伟鹏 《现代城市轨道交通》2021,(4):38-41
牵引传动系统是轨道交通车辆装备实现机电能量转换的“心脏”单元,其性能在某种程度上决定轨道交通车辆的动力品质、能耗和控制特性,是轨道交通车辆节能升级的关键系统。而永磁同步牵引系统以其高效率、高可靠性和低能耗的优势特点,受到轨道交通行业的密切关注。文章阐述深圳地铁10号线永磁同步牵引系统批量装车概况,重点分析永磁同步牵引系统组成及优势,指出推广应用永磁同步牵引系统的经济和社会效益显著。 相似文献
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Real-Time Fault Diagnosis for Gas Turbine Blade Based on Output-Hidden Feedback Elman Neural Network
In order to remotely monitor and maintain large-scale complex equipment in real time, China Telecom plans to create a total solution that integrates remote data collection, transmission, storage, analysis and prediction. This solution can provide manufacturers with proactive, systematic, integrated operation and maintenance service, and the data analysis and health forecasting are the most important part. This paper conducts health management for the turbine blades. Elman neural network, and improved Elman neural network, i.e., outputhidden feedback (OHF) Elman neural network are studied as the main research methods. The results verify the applicability of OHF Elman neural network. 相似文献
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分析了电阻点焊原理,对相同的点焊搭接方式,分别采用3种工况进行焊接试验。3种工况分别采用相同焊接参数对搭接接触面涂导电密封胶和不涂导电密封胶的试件进行焊接;优化焊接参数后,对搭接接触面涂导电密封胶的试验件进行焊接。对3种工况下完成的焊接试件进行拉伸力检测试验、金相熔核尺寸检测和缺陷检测试验,对熔核直径、拉伸力、熔核内部缺陷的试验结果进行分析。试验结果表明:导电密封胶对电阻点焊的焊接性能存在影响;通过适当优化焊接参数,可以提高涂导电密封胶试件的焊接性能,焊接质量能够满足产品焊接要求。 相似文献