目前,民航气象业务的常见传输方式是同步数字体系(Synchronous Digital System,SDH)光传输。该方式提高了带宽的利用率,具有一定的优势,但也存在一定的不足。因此,讨论了采用弹性分组环(Resilient Packet Ring,RPR)技术的升级SDH光传输...目前,民航气象业务的常见传输方式是同步数字体系(Synchronous Digital System,SDH)光传输。该方式提高了带宽的利用率,具有一定的优势,但也存在一定的不足。因此,讨论了采用弹性分组环(Resilient Packet Ring,RPR)技术的升级SDH光传输技术在民航气象业务中的应用。该技术强大的保护能力、业务分级、公平算法等特点对于民航气象业务传输来说优势明显。同时,本研究讨论了应用RPR技术后各种民航气象业务的分级传输。对于建设一个满足多业务传输的民航气象通信网络,RPR技术具有很大的潜力。展开更多
An investigation of the errors resulted from distribution curve transformations using six different methods was made on the basis of 61 sets of jig performance test data from the coal preparation plants in China. The ...An investigation of the errors resulted from distribution curve transformations using six different methods was made on the basis of 61 sets of jig performance test data from the coal preparation plants in China. The results indicate that minimum error occurred when distribution curves were transformed by keeping imperfection I constant. Generalized distribution curves are developed for jigs and their applications are discussed.展开更多
Based on an exact CAD model of hydro-mechanical continuously variable transmission （HMCVT） gearbox which can transmit 180 horsepower, virtual prototype of the HMCVT was built. Revolution speed of shafts, gears and c...Based on an exact CAD model of hydro-mechanical continuously variable transmission （HMCVT） gearbox which can transmit 180 horsepower, virtual prototype of the HMCVT was built. Revolution speed of shafts, gears and clutches of the HMCVT were calibrated by using results obtained by theoretical calculation and test methods. The needed power and torques of both mechanical power input shaft and hydropower input shaft were calculated by simulation. Hydraulic power distributing ratio and power flow of the system was also studied. The analysis results showed that cycle power was produced inevitably when the output shaft speed of HMCVT change smoothly during mechanical and hydraulic working state HM1 to HM4, and the instantaneous maximum cycle power was 39.5%. Then the overall transmission efficiency of HMCVT was studied, and the maximum overall efficiency of the system was about 87%. The results of the studies gave references to select suited engine and variable displacement pump for the HMCVT, and to develop rational speed control strategies for the HMCVT by changing displacement ratio of variable displacement pump.展开更多
文摘目前,民航气象业务的常见传输方式是同步数字体系(Synchronous Digital System,SDH)光传输。该方式提高了带宽的利用率,具有一定的优势,但也存在一定的不足。因此,讨论了采用弹性分组环(Resilient Packet Ring,RPR)技术的升级SDH光传输技术在民航气象业务中的应用。该技术强大的保护能力、业务分级、公平算法等特点对于民航气象业务传输来说优势明显。同时,本研究讨论了应用RPR技术后各种民航气象业务的分级传输。对于建设一个满足多业务传输的民航气象通信网络,RPR技术具有很大的潜力。
文摘An investigation of the errors resulted from distribution curve transformations using six different methods was made on the basis of 61 sets of jig performance test data from the coal preparation plants in China. The results indicate that minimum error occurred when distribution curves were transformed by keeping imperfection I constant. Generalized distribution curves are developed for jigs and their applications are discussed.
基金The authors acknowledge the support of Project supported by recommend international advanced agricultural science and technology plan of Ministry of Agriculture of China （Grant No. 2010-Z18）, and the National Natural Science Foundation of China （Grant No. 51275249）.
文摘Based on an exact CAD model of hydro-mechanical continuously variable transmission （HMCVT） gearbox which can transmit 180 horsepower, virtual prototype of the HMCVT was built. Revolution speed of shafts, gears and clutches of the HMCVT were calibrated by using results obtained by theoretical calculation and test methods. The needed power and torques of both mechanical power input shaft and hydropower input shaft were calculated by simulation. Hydraulic power distributing ratio and power flow of the system was also studied. The analysis results showed that cycle power was produced inevitably when the output shaft speed of HMCVT change smoothly during mechanical and hydraulic working state HM1 to HM4, and the instantaneous maximum cycle power was 39.5%. Then the overall transmission efficiency of HMCVT was studied, and the maximum overall efficiency of the system was about 87%. The results of the studies gave references to select suited engine and variable displacement pump for the HMCVT, and to develop rational speed control strategies for the HMCVT by changing displacement ratio of variable displacement pump.
