Prticle-in-cell（PIC） simulations demonstrated that,when the relativistic magnetron with diffraction output（MDO） is applied with a 410 kV voltage pulse,or when the relativistic magnetron with radial output is appli...Prticle-in-cell（PIC） simulations demonstrated that,when the relativistic magnetron with diffraction output（MDO） is applied with a 410 kV voltage pulse,or when the relativistic magnetron with radial output is applied with a 350 kV voltage pulse,electrons emitted from the cathode with high energy will strike the anode block wall.The emitted secondary electrons and backscattered electrons affect the interaction between electrons and RF fields induced by the operating modes,which decreases the output power in the radial output relativistic magnetron by about 15%（10%for the axial output relativistic magnetron）,decreases the anode current by about 5%（5%for the axial output relativistic magnetron）,and leads to a decrease of electronic efficiency by 8%（6%for the axial output relativistic magnetron）.The peak value of the current formed by secondary and backscattered current equals nearly half of the amplitude of the anode current,which may help the growth of parasitic modes when the applied magnetic field is near the critical magnetic field separating neighboring modes.Thus,mode competition becomes more serious.展开更多
The Cu-Ni-W alloys for the liners for shaped charges were successfully prepared by direct current（DC） electrodeposition.The influence of cathode current density on morphology,microstructure and composition of the Cu...The Cu-Ni-W alloys for the liners for shaped charges were successfully prepared by direct current（DC） electrodeposition.The influence of cathode current density on morphology,microstructure and composition of the Cu-Ni-W alloys was investigated by means of scanning electron microscopy（SEM）,X-ray diffraction（XRD） and energy dispersive spectrometry（EDS）.With the increasing of current density,the copper content reduces gradually and the nickel and tungsten content increase; the crystallite size is decreased.When the current density is 15 A/dm 2 the tungsten content reaches 12.96 wt pct,and the crystallite size is submicron degree.The Cu-Ni-W alloy is face-centered cubic（fcc） solid solution.All of the Cu-Ni-W alloys take on（220） texture.展开更多
基金supported by National Natural Science Foundation of China(No.61302010)the Foundation of Science and Technology on High Power Microwave Laboratory,Central University Foundation(2013KW07)Work at the University of New Mexico in USA was supportedby ONR Grant N00014-13-1-0565
文摘Prticle-in-cell（PIC） simulations demonstrated that,when the relativistic magnetron with diffraction output（MDO） is applied with a 410 kV voltage pulse,or when the relativistic magnetron with radial output is applied with a 350 kV voltage pulse,electrons emitted from the cathode with high energy will strike the anode block wall.The emitted secondary electrons and backscattered electrons affect the interaction between electrons and RF fields induced by the operating modes,which decreases the output power in the radial output relativistic magnetron by about 15%（10%for the axial output relativistic magnetron）,decreases the anode current by about 5%（5%for the axial output relativistic magnetron）,and leads to a decrease of electronic efficiency by 8%（6%for the axial output relativistic magnetron）.The peak value of the current formed by secondary and backscattered current equals nearly half of the amplitude of the anode current,which may help the growth of parasitic modes when the applied magnetic field is near the critical magnetic field separating neighboring modes.Thus,mode competition becomes more serious.
文摘The Cu-Ni-W alloys for the liners for shaped charges were successfully prepared by direct current（DC） electrodeposition.The influence of cathode current density on morphology,microstructure and composition of the Cu-Ni-W alloys was investigated by means of scanning electron microscopy（SEM）,X-ray diffraction（XRD） and energy dispersive spectrometry（EDS）.With the increasing of current density,the copper content reduces gradually and the nickel and tungsten content increase; the crystallite size is decreased.When the current density is 15 A/dm 2 the tungsten content reaches 12.96 wt pct,and the crystallite size is submicron degree.The Cu-Ni-W alloy is face-centered cubic（fcc） solid solution.All of the Cu-Ni-W alloys take on（220） texture.
