Recent research progresses in Multi-Beam Klystron (MBK) in IECAS are briefly introduced in the letter. The S-band MBKs of IECAS have peak power of 120-250 kW, average power of 4-9 kW, efficiency of 35-45%, gain of 41-...Recent research progresses in Multi-Beam Klystron (MBK) in IECAS are briefly introduced in the letter. The S-band MBKs of IECAS have peak power of 120-250 kW, average power of 4-9 kW, efficiency of 35-45%, gain of 41-46 dB, beam voltage of 15-19 kV, and weight of 40-45 kg. Some key technical problems of MBK are also described and discussed. Among them,improving the design of MBK to obtain the required bandwidth, raising beam transmission to increase average power, eliminating oscillation and spray spectrum, overcoming window breakdown caused by magic mode, reducing breakdown times of electrongun, are most important things for the practical MBK. Besides, further research work in MBK in IECAS is commented.展开更多
The time reversal is an unique self-adaptive focusing technique important to ultrasonic imaging. In this paper, the principle and the analytic expression of the ultrasound field in the realization of time reversal du...The time reversal is an unique self-adaptive focusing technique important to ultrasonic imaging. In this paper, the principle and the analytic expression of the ultrasound field in the realization of time reversal during the presence of an interface between two media are presented. Experimental results of time reversal are given and found to agree with theoretical ones.展开更多
文摘Recent research progresses in Multi-Beam Klystron (MBK) in IECAS are briefly introduced in the letter. The S-band MBKs of IECAS have peak power of 120-250 kW, average power of 4-9 kW, efficiency of 35-45%, gain of 41-46 dB, beam voltage of 15-19 kV, and weight of 40-45 kg. Some key technical problems of MBK are also described and discussed. Among them,improving the design of MBK to obtain the required bandwidth, raising beam transmission to increase average power, eliminating oscillation and spray spectrum, overcoming window breakdown caused by magic mode, reducing breakdown times of electrongun, are most important things for the practical MBK. Besides, further research work in MBK in IECAS is commented.
基金This project supported by National Natural Science Foundation of China and the President Foundationof Institute of Acoustics
文摘The time reversal is an unique self-adaptive focusing technique important to ultrasonic imaging. In this paper, the principle and the analytic expression of the ultrasound field in the realization of time reversal during the presence of an interface between two media are presented. Experimental results of time reversal are given and found to agree with theoretical ones.
