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面对新冠肺炎疫情防控人民战争、总体战和阻击战的重大考验,交通运输行业主动担当、积极应对,充分发挥了有力的支撑保障作用,同时也暴露出了一些问题与不足。面对新冠肺炎疫情“大考”,首先,系统总结了“中国交通之治”的积极成效与经验,并进一步剖析存在的主要问题及其原因;其次,在全面把握疫情防控对交通运输治理深远影响的基础上,提出了推进交通治理体系和治理能力现代化面临的重大机遇与挑战;最后,从树立“交通之志”、汇聚“交通之智”、完善“交通之制”、成就“交通之治”等四个方面,提出了加快推进交通运输治理体系和治理能力现代化的政策建议。研究成果可为交通运输部门深化治理改革与管理决策提供参考。 相似文献
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The deflection properties of elastic stage, elastoplastic stage and plastic stage of elastomer were analyzed. Taking account of the kinetic friction force in friction interface and strain hardening in slow sliding interface, the elastic, elastoplastic and plastic normal contact stiffness model for harsh surface was established, which revised the Majumdar-Bhushan fractal model and made it more perfect. In the combination of macro and micro perspective, the effects of coarse surface fractal variables, kinetic friction force in the friction interface, material characters of the friction couples on the contact status and contact property were discussed by the study of digital analysis. Results imply that the normal contact stiffness improves with the increasing real contact area and normal contact load, and reduces with the augment of kinetic friction coefficient. When the kinetic friction coefficient is smaller than 0.3, the normal contact stiffness comprises a linear decrease with the increment of kinetic friction coefficient. When the kinetic friction coefficient is bigger than 0.3, the normal contact stiffness has an exponential decrease with the increasing kinetic friction coefficient. 相似文献
85.
为实现地铁车辆走行部关键部件的不解体检测诊断,采用过车轨道振动来分析车辆平轮故障。试验采集了正常情况、剥离故障及擦伤故障等3种工况下的振动信号。首先对信号进行集合经验模态分解;然后,用相关系数法筛选分解产生的本征模态函数分量,再计算主分量的模糊熵熵值作为故障特征向量;最后,输入到由遗传算法优化的支持向量机分类器进行故障识别。试验结果表明,该方法可以实现地铁车辆平轮故障的准确识别。 相似文献
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This paper describes an optimal vehicle speed controller that uses torque-based control concepts. The controller design was
divided into two steps: first, for a given vehicle speed trajectory, the engine torque demand was determined; in the second
stage, a torque controller was implemented to track this torque demand. The torque demand was determined by a primary component
and a correction component. The primary component was determined by solving an off-line optimization problem, and the correction
component was added to compensate for the error caused by the off-line optimization. A modelbased proportional-integral (PI)
feedback torque controller was employed to realize the engine torque tracking. Simulation results generated by a benchmark
simulator were given to demonstrate performance of the optimal vehicle speed controller and a conventional PI speed controller
that was included for comparison. 相似文献
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