The basic process of re-ionization loss was studied.In the drift duct there are three processes leading to re-ionization loss：the collision of neutral beam particles with the molecules of background gas,similar colli...The basic process of re-ionization loss was studied.In the drift duct there are three processes leading to re-ionization loss：the collision of neutral beam particles with the molecules of background gas,similar collisions with released molecules from the inner wall of the drift duct and the ferret-collisions among particles with different energy of the neutral beam.Mathematical models have been developed and taking EAST-NBI parameters as an example,the re-ionization loss was obtained within these models.The result indicated that in the early stage of the neutral beam injector operation the released gas was quite abundant.The amount of re-ionization loss owing to the released gas can be as high as 60%.In the case of a long-time operation of the neutral beam injector,the total re-ionization loss decreases from 13.7% to 5.7%.Then the reionization loss originating mainly from the collisions between particles of the neutral beam and the background molecules is dominant,covering about 92% of the total re-ionization loss.The drift duct pressure was the decisive factor for neutral beam re-ionization loss.展开更多
This paper reports that the ratios of double to single electron loss cross-section （R） of O^2＋ in collision with Ar and He at the velocity of 1 -4 vo（vo is the Bohr velocity） have been obtained by the coincidence...This paper reports that the ratios of double to single electron loss cross-section （R） of O^2＋ in collision with Ar and He at the velocity of 1 -4 vo（vo is the Bohr velocity） have been obtained by the coincidence technique. The trend of R - V in the experiment indicates that the effective charge varies with injected velocity. The effective charge can be obtained by the n-body classical trajectory Monte Carlo method, which is interpreted by the molecular Coulomb over barrier model.展开更多
In this research, an Adaptive Distributed Inter Frame Space (ADIFS) has been proposed for IEEE 802.11 Medium Access Control (MAC) protocol. The aim of this approach is to improve Quality of Services (QoS) for IEEE 802...In this research, an Adaptive Distributed Inter Frame Space (ADIFS) has been proposed for IEEE 802.11 Medium Access Control (MAC) protocol. The aim of this approach is to improve Quality of Services (QoS) for IEEE 802.11 MAC protocol in single-hop wireless network. The proposed approach is based on traffic type, Collision Rate (CR), Collision Rate Variation (CRV) and Packet Loss Rate. These parameters are used to adjust the DIFS at runtime. The adjusted DIFS is employed to enhance service differentiation at the MAC layer in single-hop wireless networks. The proposed approach contributes to the enhancement of the average QoS for high priority traffic by 32.9% and 33.4% for the 5 and 10 connections, respectively. While the average QoS for the low priority traffic is improved by 14.3% and 18.2% for the 5 and 10 connections, respectively. The results indicate that, the proposed approach contributes in the enhancement of the QoS in wireless network.展开更多
以太网的帧传输在数据位出错、接收缓冲区满或其他异常情况下,接收器会简单地丢弃帧,特别是在高速传输或网络互连设备中更为明显。虽然以太网提供了重传机制,但是这样会带来延时的不确定性,为传输电路数据的时钟特性,适应以太网承载电...以太网的帧传输在数据位出错、接收缓冲区满或其他异常情况下,接收器会简单地丢弃帧,特别是在高速传输或网络互连设备中更为明显。虽然以太网提供了重传机制,但是这样会带来延时的不确定性,为传输电路数据的时钟特性,适应以太网承载电路数据 IP 包的需求,通过分析以太网数据传输特点,提出了一种包丢失及延时补偿的设计方法,并在 FPGA 中实现了包丢失补偿的缓冲器设计。展开更多
Motion behavior of grinding balls plays a vital role in improving efficiency of particle crushing.A method of preparing micro-particles by changing ball-motion behavior in a flutter mill is proposed and multiple grind...Motion behavior of grinding balls plays a vital role in improving efficiency of particle crushing.A method of preparing micro-particles by changing ball-motion behavior in a flutter mill is proposed and multiple grinding experiments are conducted.Crushing performance parameters,such as breakage rate Si,production rates of fine particles Fi and Fi*,are studied in different motion conditions.From the results,a better crushing performance is attained in the coupled motion modes of rotating speed ratio of 85%,with a vibrating amplitude of 8 mm and a frequency of 12 Hz.In addition,the influence of ball-motion behavior on particle crushing performance is discussed.The ball-motion behaviors,such as the collision energy loss E,among grinding balls have some relationship with the particle crushing performance of Si.Therefore,this study not just provides an efficiency way of accumulating micro-particles,but also reveals how the ball-motion behavior influence particle crushing performance in the flutter mill.展开更多
基于微米沙尘高温弹塑性碰撞理论及沙尘-壁面碰撞沉积模型和两相流理论,研究了不同温度下1~5μm沙尘与镍基单晶材料壁面碰撞沉积特性,分析了气流流动特性、颗粒运动轨迹和碰撞沉积结果等,研究了粒径和温度对微米沙尘碰撞率、沉积率和捕...基于微米沙尘高温弹塑性碰撞理论及沙尘-壁面碰撞沉积模型和两相流理论,研究了不同温度下1~5μm沙尘与镍基单晶材料壁面碰撞沉积特性,分析了气流流动特性、颗粒运动轨迹和碰撞沉积结果等,研究了粒径和温度对微米沙尘碰撞率、沉积率和捕捉率的影响。结果表明:微米沙尘在通道输送过程中不同出口位置处运动轨迹差异较大;温度为1323 K时,直径1~5μm沙尘碰撞率随粒径减小而减小,1μm沙尘沉积率和捕捉率最大,分别为37.86%和6.049%,2μm以上沙尘沉积率和捕捉率相对较小;直径1μm沙尘在1273,1323和1343 K 3种温度下沉积率和捕捉率随温度升高而增大。展开更多
基金Supported by National Science Foundation Project (10875146,10575105)Chinese Academy of Sciences Knowledge Innovation Project the Study of Neutral Beam Steady-State Operation of the Key Technical and Physical Problems
文摘The basic process of re-ionization loss was studied.In the drift duct there are three processes leading to re-ionization loss：the collision of neutral beam particles with the molecules of background gas,similar collisions with released molecules from the inner wall of the drift duct and the ferret-collisions among particles with different energy of the neutral beam.Mathematical models have been developed and taking EAST-NBI parameters as an example,the re-ionization loss was obtained within these models.The result indicated that in the early stage of the neutral beam injector operation the released gas was quite abundant.The amount of re-ionization loss owing to the released gas can be as high as 60%.In the case of a long-time operation of the neutral beam injector,the total re-ionization loss decreases from 13.7% to 5.7%.Then the reionization loss originating mainly from the collisions between particles of the neutral beam and the background molecules is dominant,covering about 92% of the total re-ionization loss.The drift duct pressure was the decisive factor for neutral beam re-ionization loss.
基金supported by the Special Foundation for State Major Basic Research Program of China (Grant No 2002CCA00900)
文摘This paper reports that the ratios of double to single electron loss cross-section （R） of O^2＋ in collision with Ar and He at the velocity of 1 -4 vo（vo is the Bohr velocity） have been obtained by the coincidence technique. The trend of R - V in the experiment indicates that the effective charge varies with injected velocity. The effective charge can be obtained by the n-body classical trajectory Monte Carlo method, which is interpreted by the molecular Coulomb over barrier model.
文摘In this research, an Adaptive Distributed Inter Frame Space (ADIFS) has been proposed for IEEE 802.11 Medium Access Control (MAC) protocol. The aim of this approach is to improve Quality of Services (QoS) for IEEE 802.11 MAC protocol in single-hop wireless network. The proposed approach is based on traffic type, Collision Rate (CR), Collision Rate Variation (CRV) and Packet Loss Rate. These parameters are used to adjust the DIFS at runtime. The adjusted DIFS is employed to enhance service differentiation at the MAC layer in single-hop wireless networks. The proposed approach contributes to the enhancement of the average QoS for high priority traffic by 32.9% and 33.4% for the 5 and 10 connections, respectively. While the average QoS for the low priority traffic is improved by 14.3% and 18.2% for the 5 and 10 connections, respectively. The results indicate that, the proposed approach contributes in the enhancement of the QoS in wireless network.
文摘以太网的帧传输在数据位出错、接收缓冲区满或其他异常情况下,接收器会简单地丢弃帧,特别是在高速传输或网络互连设备中更为明显。虽然以太网提供了重传机制,但是这样会带来延时的不确定性,为传输电路数据的时钟特性,适应以太网承载电路数据 IP 包的需求,通过分析以太网数据传输特点,提出了一种包丢失及延时补偿的设计方法,并在 FPGA 中实现了包丢失补偿的缓冲器设计。
基金the National Natural Science Foundation of China(Nos.51675484,51275474)Zhejiang Provincial Natural Sci⁃ence Foundation of China(No.LZ12E05002)。
文摘Motion behavior of grinding balls plays a vital role in improving efficiency of particle crushing.A method of preparing micro-particles by changing ball-motion behavior in a flutter mill is proposed and multiple grinding experiments are conducted.Crushing performance parameters,such as breakage rate Si,production rates of fine particles Fi and Fi*,are studied in different motion conditions.From the results,a better crushing performance is attained in the coupled motion modes of rotating speed ratio of 85%,with a vibrating amplitude of 8 mm and a frequency of 12 Hz.In addition,the influence of ball-motion behavior on particle crushing performance is discussed.The ball-motion behaviors,such as the collision energy loss E,among grinding balls have some relationship with the particle crushing performance of Si.Therefore,this study not just provides an efficiency way of accumulating micro-particles,but also reveals how the ball-motion behavior influence particle crushing performance in the flutter mill.
文摘基于微米沙尘高温弹塑性碰撞理论及沙尘-壁面碰撞沉积模型和两相流理论,研究了不同温度下1~5μm沙尘与镍基单晶材料壁面碰撞沉积特性,分析了气流流动特性、颗粒运动轨迹和碰撞沉积结果等,研究了粒径和温度对微米沙尘碰撞率、沉积率和捕捉率的影响。结果表明:微米沙尘在通道输送过程中不同出口位置处运动轨迹差异较大;温度为1323 K时,直径1~5μm沙尘碰撞率随粒径减小而减小,1μm沙尘沉积率和捕捉率最大,分别为37.86%和6.049%,2μm以上沙尘沉积率和捕捉率相对较小;直径1μm沙尘在1273,1323和1343 K 3种温度下沉积率和捕捉率随温度升高而增大。
