排序方式: 共有42条查询结果,搜索用时 31 毫秒
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以大秦线2亿t扩能改造工程为例,通过对AT牵引供电系统在AT所并联、不并联2种情况下阻抗特性的比较和分析,提出了全并联AT牵引供电方式继电保护配置方案和保护整定原则. 相似文献
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浅谈馈线热过负荷保护在电气化铁道中的应用 总被引:1,自引:1,他引:0
针对电气化铁道高速、重载对接触网的要求,分析了馈线热过负荷保护的动作原理、整定原则,提出了采用热过负荷保护对接触网进行保护并预测了今后的应用前景。 相似文献
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本文介绍两种汽车发动机气门弹簧的优化设计,即在发动机气门弹簧安装尺寸不变的情况下的改进设计和发动机全新设计。通过优化设计可得到体积和质量均小,结构十分紧凑的双气门弹簧。 相似文献
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To determine the physical significance of the impact toughness parameters and accurately characterize the low temperature impact toughness of transmission tower material Q420 B,the finite element model of Charpy impact test is established on the basis of experiment.The simulation and test results are verified,and the specimen fracture is analyzed by scanning electron microscope.The formation and growth mechanism of the crack are dynamically analyzed.On this basis,energy separation method is used to investigate the effect of low temperature on impact toughness.The results show that the simulation and test results are in good agreement,and the ductile-brittle transition temperature of Q420 B is about-50 ℃.The breaking process of the specimen is divided into the crack formation and propagation.When temperature drops from 20 to-60 ℃,the crack propagation energy decreases from 51.0 to 11.9 J,the crack formation energy reduces from 39.9 to 15.8 J,and the fracture time of the material drops from 1.8 to 0.6 ms. 相似文献
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