A heavy-haul train-track coupled model is developed. Taking the emergency braking of the 2×104 t combined train as example, the train longitudinal impulse, the coupler dynamic behaviors and wheel-rail interaction...A heavy-haul train-track coupled model is developed. Taking the emergency braking of the 2×104 t combined train as example, the train longitudinal impulse, the coupler dynamic behaviors and wheel-rail interactions of vehicles distributing in the different positions are analyzed. The results indicate that under the coupler compressing forces, the couplers of middle locomotives may tilt to the free swing limits, which induces the unidirectional tilt of their connected wagon couplers. Consequently, the coupler longitudinal forces produce the lateral components, and then affect the wheel-rail dynamic interaction. The performance of the middle locomotive and their neighboring freight wagons deteriorate significantly, becoming the most dangerous parts in the combined train. The wagons disconnecting with the locomotives can basically keep their couplers to stabilize in the centering positions, even though the maximum coupler longitudinal force acts on it. And its corresponding running safety also has little changes.展开更多
Currently, pediatric emergency medicine （PEM） as practiced in many developed countries is different from ours in China. Chinese pediatric emergency medicine is just children＇s internal medicine and does not include...Currently, pediatric emergency medicine （PEM） as practiced in many developed countries is different from ours in China. Chinese pediatric emergency medicine is just children＇s internal medicine and does not include general surgery, ear-nose-throat, etc. If children have an emergency condition that require specialized treatments they need to go to different departments. However in Canada, the pediatric emergency physicians will first treat the patients whatever the condition, then, if it is a complicated sub specialty problem, they will consult the specialist or let the patient see the specialist later. In addition, resuscitation is done in the pediatric intensive care unit （PICU） in China, but it is done in the emergency room in Canada. This article compares the differences in the pediatric emergency systems in Canada and China and also introduces the international standard system of pediatric triage.展开更多
Amother considers her child to be a continuation of her own life, and places her own desires that she cannot achieve on her child. A child is a mother’s sun, a mother’s hope. In this world, however, there exists ano...Amother considers her child to be a continuation of her own life, and places her own desires that she cannot achieve on her child. A child is a mother’s sun, a mother’s hope. In this world, however, there exists another group of mothers whose children have autism. These children act as if they are completely alone, do not interact with others, and even refuse the love展开更多
基金Projects(51605315,51478399)supported by the National Natural Science Foundation of ChinaProject(2013BAG20B00)supported by the National Key Technology R&D Program of ChinaProject(TPL1707)supported by the Open Project Program of the State Key Laboratory of Traction Power,China
文摘A heavy-haul train-track coupled model is developed. Taking the emergency braking of the 2×104 t combined train as example, the train longitudinal impulse, the coupler dynamic behaviors and wheel-rail interactions of vehicles distributing in the different positions are analyzed. The results indicate that under the coupler compressing forces, the couplers of middle locomotives may tilt to the free swing limits, which induces the unidirectional tilt of their connected wagon couplers. Consequently, the coupler longitudinal forces produce the lateral components, and then affect the wheel-rail dynamic interaction. The performance of the middle locomotive and their neighboring freight wagons deteriorate significantly, becoming the most dangerous parts in the combined train. The wagons disconnecting with the locomotives can basically keep their couplers to stabilize in the centering positions, even though the maximum coupler longitudinal force acts on it. And its corresponding running safety also has little changes.
文摘Currently, pediatric emergency medicine （PEM） as practiced in many developed countries is different from ours in China. Chinese pediatric emergency medicine is just children＇s internal medicine and does not include general surgery, ear-nose-throat, etc. If children have an emergency condition that require specialized treatments they need to go to different departments. However in Canada, the pediatric emergency physicians will first treat the patients whatever the condition, then, if it is a complicated sub specialty problem, they will consult the specialist or let the patient see the specialist later. In addition, resuscitation is done in the pediatric intensive care unit （PICU） in China, but it is done in the emergency room in Canada. This article compares the differences in the pediatric emergency systems in Canada and China and also introduces the international standard system of pediatric triage.
文摘Amother considers her child to be a continuation of her own life, and places her own desires that she cannot achieve on her child. A child is a mother’s sun, a mother’s hope. In this world, however, there exists another group of mothers whose children have autism. These children act as if they are completely alone, do not interact with others, and even refuse the love
