A new video-based measurement is proposed to collect and investigate traffic flow parameters. The output of the measurement is velocity-headway distance data pairs. Because density can be directly acquired by the reci...A new video-based measurement is proposed to collect and investigate traffic flow parameters. The output of the measurement is velocity-headway distance data pairs. Because density can be directly acquired by the reciprocal of headway distance, the data pairs have the advantage of better simultaneity than those from common detectors. By now, over 33 000 pairs of data have been collected from two road sections in the cities of Shanghai and Zhengzhou. Through analyzing the video files recording traffic movements on urban expressways, the following issues are studied：laws of vehicle velocity changing with headway distance, proportions of di0erent driving behaviors in the traffic system, and characteristics of traffic flow in snowy days. The results show that the real road traffic is very complex, and factors such as location and climate need to be taken into consideration in the formation of traffic flow models.展开更多
Core plasma rotation of both L-mode and H-mode discharges with ion cyclotron range of frequency（ICRF） minority heating（MH） scheme was measured with a tangential X-ray imaging crystal spectrometer on EAST（Experime...Core plasma rotation of both L-mode and H-mode discharges with ion cyclotron range of frequency（ICRF） minority heating（MH） scheme was measured with a tangential X-ray imaging crystal spectrometer on EAST（Experimental Advanced Superconducting Tokamak）.Cocurrent central impurity toroidal rotation change was observed in ICRF-heated L-and H-mode plasmas.Rotation increment as high as 30 km/s was generated at ~1.7 MW ICRF power.Scaling results showed similar trend as the Rice scaling but with significant scattering,especially in L-mode plasmas.We varied the plasma current,toroidal field and magnetic configuration individually to study their effect on L-mode plasma rotation,while keeping the other major plasma parameters and heating unchanged during the scanning.It was found that larger plasma current could induce plasma rotation more efficiently.A scan of the toroidal magnetic field indicated that the largest rotation was obtained for on-axis ICRF heating.A comparison between lower-single-null（LSN）and double-null（DN） configurations showed that LSN discharges rendered a larger rotation change for the same power input and plasma parameters.展开更多
基金supported by the National Natural Science Foundation of China (10772050)
文摘A new video-based measurement is proposed to collect and investigate traffic flow parameters. The output of the measurement is velocity-headway distance data pairs. Because density can be directly acquired by the reciprocal of headway distance, the data pairs have the advantage of better simultaneity than those from common detectors. By now, over 33 000 pairs of data have been collected from two road sections in the cities of Shanghai and Zhengzhou. Through analyzing the video files recording traffic movements on urban expressways, the following issues are studied：laws of vehicle velocity changing with headway distance, proportions of di0erent driving behaviors in the traffic system, and characteristics of traffic flow in snowy days. The results show that the real road traffic is very complex, and factors such as location and climate need to be taken into consideration in the formation of traffic flow models.
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2013GB112004 and 2015GB103002)National Natural Science Foundation of China(Nos.11175208,11305212,11375235,11405212 and 11261140328)+1 种基金the Innovative Program of Development Foundation of Hefei Center for Physical Science and Technology(2014FXCX003)Brain Korea 21 Program for Leading Universities&Students(BK21 PLUS)
文摘Core plasma rotation of both L-mode and H-mode discharges with ion cyclotron range of frequency（ICRF） minority heating（MH） scheme was measured with a tangential X-ray imaging crystal spectrometer on EAST（Experimental Advanced Superconducting Tokamak）.Cocurrent central impurity toroidal rotation change was observed in ICRF-heated L-and H-mode plasmas.Rotation increment as high as 30 km/s was generated at ~1.7 MW ICRF power.Scaling results showed similar trend as the Rice scaling but with significant scattering,especially in L-mode plasmas.We varied the plasma current,toroidal field and magnetic configuration individually to study their effect on L-mode plasma rotation,while keeping the other major plasma parameters and heating unchanged during the scanning.It was found that larger plasma current could induce plasma rotation more efficiently.A scan of the toroidal magnetic field indicated that the largest rotation was obtained for on-axis ICRF heating.A comparison between lower-single-null（LSN）and double-null（DN） configurations showed that LSN discharges rendered a larger rotation change for the same power input and plasma parameters.
