The pantograph-catenary arc has persistently posed a challenge,impeding the advancement of high-speed rail systems.As the velocity of high-speed trains continues to escalate and environmental conditions become increas...The pantograph-catenary arc has persistently posed a challenge,impeding the advancement of high-speed rail systems.As the velocity of high-speed trains continues to escalate and environmental conditions become increasingly complex,the phenomenon of pantograph-catenary arc drifting has intensified,thereby jeopardizing the safe operation of trains.To enhance the stability of the pantograph-catenary arc,this paper proposes a method to regulate arc using an AC transverse magnetic field(ATMF)and investigates the regulation law of ATMF on an arc in airflow environment.The results indicate that ATMF can effectively maintain arc stability,with the stability enhancing as the magnetic field frequency increases up to a threshold value.In an airflow environment,the stabilization effect is maximized at a frequency of 50 Hz,with arc voltage fluctuation at 4.65 V,accounting for only 5.47%of total arc voltage.It is also found that the arc temperature increases with the frequency of the magnetic field,reaching 4743 K at 10 Hz and 4976 K at 1000 Hz.In addition,the effects of sinusoidal,triangular and rectangular magnetic field excitation currents on the arc are investigated,and it is found that the arc shows the greatest stability in the triangular field,with a voltage fluctuation of 3.04 V.This study provides theoretical support for the application of ATMF regulation to enhance the stability of the pantograph-catenary arc.展开更多
Attenuating the noises plays an essential role in the image processing. Almost all the traditional median filters concern the removal of impulse noise having a single layer, whose noise gray level value is constant. I...Attenuating the noises plays an essential role in the image processing. Almost all the traditional median filters concern the removal of impulse noise having a single layer, whose noise gray level value is constant. In this paper, a new adaptive median filter is proposed to handle those images corrupted not only by single layer noise. The adaptive threshold median filter （ATMF） has been developed by combining the adaptive median filter （AMF） and two dynamic thresholds. Because of the dynamic threshold being used, the ATMF is able to balance the removal of the multiple-impulse noise and the quality of image. Comparison of the proposed method with traditional median filters is provided. Some visual examples are given to demonstrate the performance of the proposed filter.展开更多
基金supported by National Natural Science Foundation of China (Nos.52322704 and 52077182)。
文摘The pantograph-catenary arc has persistently posed a challenge,impeding the advancement of high-speed rail systems.As the velocity of high-speed trains continues to escalate and environmental conditions become increasingly complex,the phenomenon of pantograph-catenary arc drifting has intensified,thereby jeopardizing the safe operation of trains.To enhance the stability of the pantograph-catenary arc,this paper proposes a method to regulate arc using an AC transverse magnetic field(ATMF)and investigates the regulation law of ATMF on an arc in airflow environment.The results indicate that ATMF can effectively maintain arc stability,with the stability enhancing as the magnetic field frequency increases up to a threshold value.In an airflow environment,the stabilization effect is maximized at a frequency of 50 Hz,with arc voltage fluctuation at 4.65 V,accounting for only 5.47%of total arc voltage.It is also found that the arc temperature increases with the frequency of the magnetic field,reaching 4743 K at 10 Hz and 4976 K at 1000 Hz.In addition,the effects of sinusoidal,triangular and rectangular magnetic field excitation currents on the arc are investigated,and it is found that the arc shows the greatest stability in the triangular field,with a voltage fluctuation of 3.04 V.This study provides theoretical support for the application of ATMF regulation to enhance the stability of the pantograph-catenary arc.
文摘Attenuating the noises plays an essential role in the image processing. Almost all the traditional median filters concern the removal of impulse noise having a single layer, whose noise gray level value is constant. In this paper, a new adaptive median filter is proposed to handle those images corrupted not only by single layer noise. The adaptive threshold median filter （ATMF） has been developed by combining the adaptive median filter （AMF） and two dynamic thresholds. Because of the dynamic threshold being used, the ATMF is able to balance the removal of the multiple-impulse noise and the quality of image. Comparison of the proposed method with traditional median filters is provided. Some visual examples are given to demonstrate the performance of the proposed filter.
