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
To the shortage of the traditional analysis methods about train impact,this paper put forward a new method us- ing autocorrelation theory and virtual instrument technology to analyze train impulse Using a double-MCU s...To the shortage of the traditional analysis methods about train impact,this paper put forward a new method us- ing autocorrelation theory and virtual instrument technology to analyze train impulse Using a double-MCU system,the accelera- tion signals were acquired at different speed by train,and were transmitted into PC through USB interface.Besides the impulse signals,the acquisition data included other useless signals.The autocorrelation function was small when trains run steadily,but was greater during train impact happened.So the autocorrelation function was adopted to distill the valid impulse data.After frequency domain analyzed and autocorrelation analyzed on the Virtual Instrument flat,a new train impulse grade assessment cri- terion was built,based on the correlation peak and the width of the peak.In experiment,the impulse signal was separated from noise signal well and truly,and the quantitative model of evaluating train impulse was believable.This system possessed a certain extent theory value and application value.展开更多
In this framework we present a new method for measurement of the UWB impulse train based on the parallel sampling of the cascaded identical RC filters. We show that the amplitudes and time locations of p sequential im...In this framework we present a new method for measurement of the UWB impulse train based on the parallel sampling of the cascaded identical RC filters. We show that the amplitudes and time locations of p sequential impulses can be reconstructed from simultaneous measurement of the outputs from 2p cascaded identical RC filters. The parallel sampling scheme has a wide range of applications including the detection of the ultra wideband (UWB) impulses. Due to identical analog RC filters and buffer amplifiers, the parallel sampling scheme is flexible to implement in VLSI applications.展开更多
This paper examines the effects of current and conductance noises in a minimal Hodgkin- Huxley type model of a cold receptor neuron. Current noise enters the membrane equation directly while conductance noise is propa...This paper examines the effects of current and conductance noises in a minimal Hodgkin- Huxley type model of a cold receptor neuron. Current noise enters the membrane equation directly while conductance noise is propagated through the activation variables. Compared with common used interspike interval method, ISI-distance is a simple complementary approach to measure the different effects of current and conductance noises. ISI-distance extracts information from the interspike intervals by evaluating the ratio of instantaneous firing rates, which is parameter-free, time scale-independent and easy to visualize. Simulation results show that the most significant differences between different noise implementations in a pacemaker-like tonic firing regime at the transition to chaotic burst discharges.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To the shortage of the traditional analysis methods about train impact,this paper put forward a new method us- ing autocorrelation theory and virtual instrument technology to analyze train impulse Using a double-MCU system,the accelera- tion signals were acquired at different speed by train,and were transmitted into PC through USB interface.Besides the impulse signals,the acquisition data included other useless signals.The autocorrelation function was small when trains run steadily,but was greater during train impact happened.So the autocorrelation function was adopted to distill the valid impulse data.After frequency domain analyzed and autocorrelation analyzed on the Virtual Instrument flat,a new train impulse grade assessment cri- terion was built,based on the correlation peak and the width of the peak.In experiment,the impulse signal was separated from noise signal well and truly,and the quantitative model of evaluating train impulse was believable.This system possessed a certain extent theory value and application value.
文摘In this framework we present a new method for measurement of the UWB impulse train based on the parallel sampling of the cascaded identical RC filters. We show that the amplitudes and time locations of p sequential impulses can be reconstructed from simultaneous measurement of the outputs from 2p cascaded identical RC filters. The parallel sampling scheme has a wide range of applications including the detection of the ultra wideband (UWB) impulses. Due to identical analog RC filters and buffer amplifiers, the parallel sampling scheme is flexible to implement in VLSI applications.
文摘This paper examines the effects of current and conductance noises in a minimal Hodgkin- Huxley type model of a cold receptor neuron. Current noise enters the membrane equation directly while conductance noise is propagated through the activation variables. Compared with common used interspike interval method, ISI-distance is a simple complementary approach to measure the different effects of current and conductance noises. ISI-distance extracts information from the interspike intervals by evaluating the ratio of instantaneous firing rates, which is parameter-free, time scale-independent and easy to visualize. Simulation results show that the most significant differences between different noise implementations in a pacemaker-like tonic firing regime at the transition to chaotic burst discharges.
