摘要：In order to test the klystrons operated at a frequency of 3.7 GHz in a continuous wave （CW） mode, a type of water load to absorb its power up to 750 kW is presented. The distilled water sealed with an RF ceramic window is used as the absorbent. At a frequency range of 70 MHz, the VSWR （Voltage Standing Wave Ratio） is below 1.2, and the rise in temperature of water is about 30 ℃ at the highest power level.

摘要：The design of 10MeV/20kW high power irradiating accelerator is *** Backward-Traveling-Wave (BTW)accelerating structure is *** structure combines the advantage of traveling-wave accelerator structure with low power reflection and high stability and standing-wave accelerator structure with high shunt *** work frequency of this accelerator is *** by Code AccDesign which is coded by ourselves,the output electron beam with final energy 10MeV and peak current 300mA was *** length of the accelerating tube is 1.5m,and the power efficiency from microwave to electron beam is 66%.The temperature and stress distribution were *** the frequency shift by microwave loss was calculated.

摘要：With the aid of a thermal-electrical model, a practical method for designing multi-finger power heterojunction bipolar transistors with finger lengths divided in groups is proposed. The method can effectively enhance the thermal stability of the devices without sacrificing the design time. Taking a 40-finger heterojunction bipolar transistor for example, the device with non-uniform emitter finger lengths is optimized and fabricated. Both the theoretical and the experimental results show that, for the optimum device, the peak temperature is lowered by 26.19 K and the maximum temperature difference is reduced by 56.67% when compared with the conventional heterojunction bipolar transistor with uniform emitter finger length. Furthermore, the ability to improve the uniformity of the temperature profile and to expand the thermal stable operation range is strengthened as the power level increases, which is ascribed to the improvement of the thermal resistance in the optimum device. A detailed design procedure is also summarized to provide a general guide for designing power heterojunction bipolar transistors with non-uniform finger lengths.

摘要：Achieving a satisfactory energy-power combination in a supercapacitor that is based on all-carbon electrodes and operates in benign aqueous media instead of conventional organic electrolytes is a major challenge. For this purpose, we fabricated carbon nanoflakes （20-100 nm in thickness, 5-μm in width） containing an unparalleled combination of a large surface area （3,000 m2-g-1 range） and mesoporosity （up to 72%）. These huge-surface area functionalized carbons （HSAFCs） also had a substantial oxygen and nitrogen content （N10 wt.% combined）, with a significant fraction of redox-active carboxyl/phenol groups in an optimized specimen. Their unique structure and chemistry resulted from a tailored single-step carbonization-activation approach employing （2-benzimidazolyl） acetonitrile combined with potassium hydroxide （KOH）. The HSAFCs exhibited specific capacitances of 474 F-g-1 at 0.5 A.g-1 and 285 F-g-1 at 100 A.g-1 （charging time 〈 3 s） in an aqueous 2 M KOH solution. These values are among the highest reported, especially at high currents. When tested with a stable 1.8-V window in a 1 M Na2SO4 electrolyte, a symmetric supercapacitor device using the fabricated nanoflakes as electrodes yielded a normalized active mass of 24.4 Wh-kg-1 at 223 W·kg-1 and 7.3 Wh·kg-1 at 9,360 W·kg-1. The latter value corresponds to a charge time of 〈3 s. The cyclability of the devices was excellent, with 93% capacitance retention after 10,000 cycles. All the electrochemical results were achieved by employing electrodes with near-commercial mass loadings of 8 mg-cm-2.

摘要：In this paper, we present a design where a bunched relativistic electron beam traversing inside the rectangular dielectric-loaded （DL） waveguide is used as a high power microwave generation device. Two kinds of methods of calculating the electromagnetic （EM） field excited by a bunched beam are introduced, and in the second method the calculation of EM pulse length is discussed in detail. The desired operating mode is the LSM11 due to its strong interaction with the electron beam. For the designed 7.8 GHz operating frequency, with a 100 nC/bunch drive train of electron bunches separated by 0.769 ns, we find that high gradient （〉 30 MV/m） and high power （〉 160 MW） can be generated. An output coupler is also designed which is able to extract the generated power to standard waveguides with a 94% coupling efficiency.

摘要：Novel carbon-carbon ultracapacitors and hybrid lithium-carbon devices are described. New approach to the design of electrode materials and electrochemical systems followed by the improved design of ultracapacitor cells and modules have resulted in prototypes of superior performance that was verified by independent tests in the Institute of Transportation Studies, UC （ultracapacitor） Davis, in JME Inc., in Wayne State University, and in some other labs. All the test results confirm the superlative performance of the devices developed： carbon-carbon ultracapacitors demonstrate the extremely low inner resistance resulting in the highest power capability and efficiency that also alleviates the cooling requirements and improves safety. Our ＂parallel＂ hybrid devices demonstrate substantially higher energy density than competing LIC （lithium ion capacitor） technologies keeping at the same time the high power density, comparable with the best carbon-carbon ultracapacitors available in the market. In order to make ultracapacitor technology even more attractive to automakers, new organic electrolytes （not ionic liquids） have been developed and are currently under testing at temperatures about 100 ℃ and voltages up to 3.0 V.

摘要：A modal analysis is conducted for analyzing the absorption profile of high power waveguide photodiodes designed for analog optical link. The excitation of guided modes with large filling factor in the absorber is identified as a limiting factor for the performance of waveguide photodiodes at high optical power, including power handling capability, and bandwidth-efficiency product. A waveguide photodiode design, which spatially separates the input waveguide from the absorber in the lateral direction, is analyzed and experimentally demon- strated to suppress the excitation of mode with large filling factor. Photocurrent 〉 60 mA under - 4 V bias is measured, with 0.80 A/W responsivity. This design illustrates that high power handling capability can be achieved without compromising the bandwidth-efficiency product.