共查询到20条相似文献,搜索用时 15 毫秒
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Shunkang Liu 《International Journal of Infrared and Millimeter Waves》2004,25(7):1061-1067
The arcing phenomenon is easy produced for high power coupled cavity traveling wave tube (CCTWT) in MW/MMW because of higher operating voltage and electric field in electronic gun region of tube. Pre-breakdown phenomenon before arcing and the reasons of leading arcing are analyzed. The effects of cathode performance for arcing in the tube are emphatically discussed. Some approaches for reducing the arcing are proposed. It is shown that arcing phenomenon in CCTWT is effectively suppressed. 相似文献
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Shunkang Liu 《International Journal of Infrared and Millimeter Waves》2003,24(5):629-638
The pill-box and block RF windows for millimeter wave (MMW) tubes are presented. The pill-box window is suitable for broadband MMW tubes. And the block window can be used for high power tubes in short MMW. The equivalent circuits for two windows are given. To reach better match characteristics in wider operating bandwidth, the optimum design methods for pill-box and block window in MMW tubes are described in this paper. The testing results show that the theoretic computation is fast and useful accuracy. The design methods possess references value to designer for MMW tubes. 相似文献
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Harvey Robin J. Lutz Michael A. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1976,4(4):210-217
A crossed field tube is used as an on-off switch to produce square, 25 ?s wide current pulses at 40 kV and 3.2 kA. Operation is also demonstrated at 120 Hz at an initial 50 kV and 1.3 kA for a ten pulse train. Calculations indicate that continuous operation at over 150 kW of average power is possible with a suitably designed cooling system. A crossed field tube operated in this way has a higher current capability and lower dissipation than hard vacuum tetrodes and could replace such tubes in higher power, lower impedance modulators. 相似文献
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GEM探测器的供电一般采用电阻链分压供电模式和多路分立供电模式,在低通量X射线下测量时区别不大,但是在高通量X射线时,电阻链分压供电模式会带来饱和效应引起工作电压的变化,造成探测器工作不稳定。本研究在高通量X 射线照射下,研究了有效面积为100 mm100 mm三层级联GEM探测器的有效增益(稳定性) 与不同高压供电模式的关系。通过测量不同分压电阻值(1, 2, 5 到30 MΩ)的实验研究,发现随着X 射线通量的增加,在电阻链分压供电模式下,出现了GEM探测器感应电极的读出电流饱和趋势,分析了可能导致饱和效应出现的原因。结果表明,当入射X射线在探测器上的有效吸收剂量不断增加时,电阻链供电模式需要调整分压单元电阻值,或者采用多路分立供电模式,从而避免因饱和效应引起的GEM探测器有效增益的变化,实现探测器稳定的工作状态。There are two methods of the HV power supply for the GEM detector. One is a HV channel divided by the resistive chain and the other is the several separate HV channels. In the smaller dose rate of X-ray, all of the methods are similar. When the dose rate increases, the resistive chain-dividing mode has more obvious saturation effect and the working voltage of the GEM detector is unstable. In the paper, a GEM detector with an effective area of 100 mm100 mm has been studied in the high dose rate using X-tube. The unit values in the divider resistance chain are set to 1, 2, 5 and 30 MΩ respectively in the test. With the resistive chain-dividing mode, the readout current of the GEM detector’s anode tends to saturate when the dose rate of X-ray increases,and the reasons of the saturation effect are analyzed. The results indicate that the effective absorbed dose of X-ray by the triple GEMs detector reaches to the pecific value and the divider resistance needs to re-select, even the several separate HV channels mode should be considered. It will keep the constant of the working voltage of the GEM detector without the saturation effect and gain variation and the performance of GEM detector is stable. 相似文献
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Numerical Investigation of Thermal Effect in Plasma Electrode Pockels Cell for High Average Power 下载免费PDF全文
The average power of a Pockels cell is limited by thermal effects arising from the optical absorption of the laser pulse. These thermal effects can be managed by configuring the switch as a plasma-electrode thin plate Pockels ceil, which works under heat-capacity operation. Simulation results show that, based on KD*P (in thickness 0.5 cm) at an average power loading of 1 kW, the aperture integrated depolarization loss at 1.06 um is less than 10% in 5min working time. 相似文献
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高功率横流CO2激光器大体积放电研究 总被引:1,自引:0,他引:1
详细讨论了脉冲预电离高功横流CO2激光器的工作特性,研究了一套新型的电极结构,对其放电,注入功率,输出功率等待进行了讨论。实验结果表明,脉冲预电离可以提高高功率横率流CO2激光器的注入和输出功率,并有效地改善了放电的稳定性和均匀性。 相似文献
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Yang Ruike Wu Zhensen You Jinguang 《International Journal of Infrared and Millimeter Waves》2003,24(8):1383-1392
The influence of sand and dust storms on modern MMW and satellite communication systems reliability have been paid more attention to. The attenuations induced by sand and dust storms are estimated by means of Mie-theory and Rayleigh approximation, in the case of the tenuous distribution of particles. With the particle density increasing, however, these method become inadequate, the multiple scattering effects then become dominant for attenuation estimation. The attenuations considering multiple scattering effects are estimated by Monte-Carlo and four fluxes method at horizontal paths. At slant paths, based on multi-layer media model, the attenuations considering multiple scattering effects are calculated by layered Monte-Carlo method at 100, 37, 24, and 14GHz. It is shown that the multiple scattering effects should be considered at the attenuation prediction in the sand and dust storm, which the visibility is about 0.5km and smaller than 0.5km and frequency is about 20GHz. Above 30GHz, the multiple scattering effects due to sand and dust particles should be considered, as visibility is about 1km and smaller than 1km at slant paths. 相似文献
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Experimental Investigation of High Power Erbium-Ytterbium Co-doped Double Clad Fibre Laser 下载免费PDF全文
All-fibre high power erbium-ytterbium co-doped double clad fibre lasers are proposed and demonstrated. By using different back-cavity mirrors, the different double clad fibre lasers are constructed. It is experimentally found that the output behaviour of laser can be controlled by a back-cavity mirror. The lower the reflectivity of the back-cavity mirror, the higher the output power and the high the slop efficiency. The maximum output power is about 1.6 W and the slop efficiency is 27.6%. 相似文献
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在用静态拉伸法测量金属丝杨氏弹性模量实验中,可以明显观察到弹性滞后现象。本文通过测量数据和弹性特性曲线直观展示了金属丝在静态拉伸时的弹性滞后现象,估算了滞后的大小。 相似文献
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介绍了秦山300MW核电机组全范围模拟机所达到的性能指标.通过分析该模拟机主要设计特点,包括核岛应用软件、主计算机和实时模拟技撑软件等,强调指出,其性能已超过了培训模拟机的要求,并对该模拟机的使用范围进行了探讨.The performance indicatrix of the full scope simulator for Qinshan 300 MW nuclear power unit is described. Main design characteristics of the simulator, including calculation models for its nuclear island, its computer and real time simulation support software, are introduced. Its performance is proved better than the requirement for use only in training operators and therefore, the fullscope simulator could be used for other studying. 相似文献
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Bosisio Renato G. Nachman Manfred Spooner Jacques 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1974,2(4):273-276
Measurements on RF power absorption in microwave discharges at 2.45 GHz, at pressures from 1 to 30 Torr in N2 and from 1 to 500 Torr in Ar, are described. A linear slow-wave structure of the strapped-bar type was employed for coupling RF energy to the plasma. From measurements on the plasma volume and on the total power absorbed, the variation with gas pressure of the RF power density in the plasma was obtained. For an incident power of 1 kW, power densities as high as 2-3 W/cm3 over relatively large plasma volumes could be achieved. The experimental data were used to calculate the pressure dependence of the electron density in an argon plasma, for an incident power of 1 kW. 相似文献
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Shunkang Liu 《International Journal of Infrared and Millimeter Waves》1998,19(4):697-703
For traditional design method of waveguide type impedance transformer, even noncontinuous susceptance produced by steps is considered, match character in wide frequency band are not satisfied commonly. In order to resolve this problem, an optimum design method is given in the paper. The computation shows that match character of the optimum designed multisection impedance transformer is better than traditional design method in MMW. 相似文献
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高功率808nm InGaAsP—GaAs分别限制结构的半导体激光器 总被引:1,自引:0,他引:1
介绍了研究分别限制结构InGaAsP-GaAs半导体激光器所得到的最新成果。利用引进的俄国技术,基于量子阱结构的InGaAsP-GaAs激光器,可用短时间液相外延技术制造。在GaAs衬底上制成的InGaAsP-GaAs分别限制结构的激光器,主要参数如下:发射波入λ=808nm,阈值电流密度J=300A/cm^2,对于条宽ω=100μm的激光器,连续功率为1-2W。 相似文献
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R32在水平细管内的流动沸腾实验研究 总被引:1,自引:0,他引:1
本文对R32在水平管内的流动沸腾进行了实验研究。实验测试段为内径2 mm的水平光滑不锈钢管,实验的蒸发温度为15℃,流量密度为100 kg/(m~2·s),热流密度为6~24 kW/m~2。通过试验获得R32的流动沸腾换热系数,同时与R134a和HFO1234yf进行比较。结果发现R32的传热系数是HFO1234yf换热系数的1~2倍。同时利用现有的公式对R32和HFO1234yf的换热系数进行了预测,发现这些公式还存在欠缺,需要进一步的改进。 相似文献