The formula for calculating the threshold of average transmitting power of cylindrical TE11 mode window is revised by accurate deduction and a practical method for calculating the temperature increment of the dielectr...The formula for calculating the threshold of average transmitting power of cylindrical TE11 mode window is revised by accurate deduction and a practical method for calculating the temperature increment of the dielectric disk in cylindrical box type window is given. Meanwhile,a typical cylindrical box type window is calculated and used as an example to discuss the power capacity, the special harmfulness and elimination of ghost mode resonance when the window is used to transmit high power Continuous Wave(CW).展开更多
A 50 mA CW deuteron RFQ is being built for a joint 973 project between Peking University and the Institute of Modern Physics. This RFQ adopts a high-frequency window-type structure. To study its RF properties and to v...A 50 mA CW deuteron RFQ is being built for a joint 973 project between Peking University and the Institute of Modern Physics. This RFQ adopts a high-frequency window-type structure. To study its RF properties and to validate the reliability of an electromagnetic simulation, two full-length aluminum models with tuners were built in succession. RF measurements were obtained from the test bench and compared to the simulations, including frequencies, quality factors, and electric fields of different modes and the field in aperture. Through field tuning, the maximal field unflatness for a single quadrant and the average asymmetry of four quadrants were reduced from 8.7% and ± 3.6% to 5.8% and ± 1.7%, respectively.Moreover, a tuning method of adjusting the gap distance between the endplates and the vanes was also studied in this paper.展开更多
With the boom of wireless devices, the number of wireless users under wireless local area networks （WLANs） has increased dramatically. However, the standard baekoff mechanism in IEEE 802.11 adopts fixed initial cont...With the boom of wireless devices, the number of wireless users under wireless local area networks （WLANs） has increased dramatically. However, the standard baekoff mechanism in IEEE 802.11 adopts fixed initial contention window （CW） size without considering changes of network load, which leads to a high collision probability and low channel utilization in bursty arrivals. In this paper, a novel CW dynamic adjustment scheme is proposed to achieve high throughput performance in dense user environment. In the proposed scheme, the initial CW size is dynamically adjusted to optimum according to the measured packet collision probability. Simulation results show that the proposed scheme can significantly improve the throughput performance.展开更多
文摘The formula for calculating the threshold of average transmitting power of cylindrical TE11 mode window is revised by accurate deduction and a practical method for calculating the temperature increment of the dielectric disk in cylindrical box type window is given. Meanwhile,a typical cylindrical box type window is calculated and used as an example to discuss the power capacity, the special harmfulness and elimination of ghost mode resonance when the window is used to transmit high power Continuous Wave(CW).
基金supported by the National Basic Research Program of China(No.2014CB845503)
文摘A 50 mA CW deuteron RFQ is being built for a joint 973 project between Peking University and the Institute of Modern Physics. This RFQ adopts a high-frequency window-type structure. To study its RF properties and to validate the reliability of an electromagnetic simulation, two full-length aluminum models with tuners were built in succession. RF measurements were obtained from the test bench and compared to the simulations, including frequencies, quality factors, and electric fields of different modes and the field in aperture. Through field tuning, the maximal field unflatness for a single quadrant and the average asymmetry of four quadrants were reduced from 8.7% and ± 3.6% to 5.8% and ± 1.7%, respectively.Moreover, a tuning method of adjusting the gap distance between the endplates and the vanes was also studied in this paper.
基金supported by the WLAN Achievement Transformation Based on Software-Defined Networking of Beijing Municipal Commission of Education (201501001)the National Natural Science Foundation of China (61671073)
文摘With the boom of wireless devices, the number of wireless users under wireless local area networks （WLANs） has increased dramatically. However, the standard baekoff mechanism in IEEE 802.11 adopts fixed initial contention window （CW） size without considering changes of network load, which leads to a high collision probability and low channel utilization in bursty arrivals. In this paper, a novel CW dynamic adjustment scheme is proposed to achieve high throughput performance in dense user environment. In the proposed scheme, the initial CW size is dynamically adjusted to optimum according to the measured packet collision probability. Simulation results show that the proposed scheme can significantly improve the throughput performance.
