TN144 2002042945用光电倍增管测量微光像增强器噪声=Testing thenoise of image intensifier with photo-multipliers[刊,中]/张伟,汪岳峰,董伟(军械工程学院光学教研室.河北,石家庄(050003))∥光电子技术.—2001,21(4).—281-283在微...TN144 2002042945用光电倍增管测量微光像增强器噪声=Testing thenoise of image intensifier with photo-multipliers[刊,中]/张伟,汪岳峰,董伟(军械工程学院光学教研室.河北,石家庄(050003))∥光电子技术.—2001,21(4).—281-283在微光像增强器成像中,迭加在图像上的时空域噪声,不仅限制系统可工作的最低照度,而且使显示图像有随机蠕动颗粒闪烁的外观。随着低噪声。展开更多
TN223 2001042802微光夜视仪最大作用距离的估算=Research on the mostoperation range’s estimation of low-light level nightvision insturments[刊,中]/牛燕雄,汪岳峰,雷鸣,张雏(军械工程学院光学与电子工程系.河北,石家庄(050003...TN223 2001042802微光夜视仪最大作用距离的估算=Research on the mostoperation range’s estimation of low-light level nightvision insturments[刊,中]/牛燕雄,汪岳峰,雷鸣,张雏(军械工程学院光学与电子工程系.河北,石家庄(050003)),陈德伟(广州军区军械雷达修理所光学室.广东,广州(510000))//光电子·激光.-2000,11(6).-620-622通过测量和分析物镜、像增强器和目镜等的性能参数,对微光夜视仪的最大作用距离进行估算。展开更多
With its unique features, photoconductive semiconductor switch (PCSS) is generally recognized today as a promising power electronic device. However, a major limitation of PCSS is its surprisingly low voltage threshold...With its unique features, photoconductive semiconductor switch (PCSS) is generally recognized today as a promising power electronic device. However, a major limitation of PCSS is its surprisingly low voltage threshold of surface flashover (SF). In this paper, an experimental study of surface flashover of a back-triggered PCSS is presented. The PCSSs with electrode gap of 18 mm are fabricated from liquid encapsulated czochralski (LEC) semi-insulating gallium arsenide (SI-GaAs), and they are either un-coated, or partly coated, or en- tirely coated PCSSs with high-strength transparent insulation. The SF fields of the PCSSs are measured and discussed. According to the experimental results, the high-dielectric-strength coating is efficient in both reducing the gas desorption from semiconductor and increasing the SF field: a well-designed PCSS can resist a voltage up to 20 kV under the repetition frequency of 30 Hz. The physical mechanism of the PCSS SF is analyzed, and the conclusion is made that having a channel structure, the SF is the breakdown of the contaminated dielectric layer at the semiconductor-ambient dielectric interface. The non-uniform distribution of the surface field and the gas desorption due to thermal effects of semiconductor surface currents are key factors causing the SF field reduction.展开更多
Starting from the uniform disk current model, an analytical solution for the electromagnetic pulse axial energy radiation is derived and a physical meaning then given to the axial energy propagation characteristics of...Starting from the uniform disk current model, an analytical solution for the electromagnetic pulse axial energy radiation is derived and a physical meaning then given to the axial energy propagation characteristics of a unit antenna. From this solution, a point-source approximation model in the time domain is introduced. Parameters such as the energy propagation characteristics and beamwidth of the electromagnetic pulse beam radiating from arrayed antenna are analyzed theoretically. An arrayed transient electromagnetic pulse generator is developed incorporating a 23×16 ultra-wideband tapered slot antenna integrated with a Blumlein formation line and photoconductive semiconductor switch. Experiments performed over a 2.5 km range confirm that the arrayed transient electromagnetic pulse can propagate in free space with the specified waveform. Moreover, the field components can be superposed in phase, and the radiation beam can be focused into a single pulse. Results from calculations are in agreement with experimental results within the measurement uncertainties.展开更多
文摘TN144 2002042945用光电倍增管测量微光像增强器噪声=Testing thenoise of image intensifier with photo-multipliers[刊,中]/张伟,汪岳峰,董伟(军械工程学院光学教研室.河北,石家庄(050003))∥光电子技术.—2001,21(4).—281-283在微光像增强器成像中,迭加在图像上的时空域噪声,不仅限制系统可工作的最低照度,而且使显示图像有随机蠕动颗粒闪烁的外观。随着低噪声。
文摘TN223 2001042802微光夜视仪最大作用距离的估算=Research on the mostoperation range’s estimation of low-light level nightvision insturments[刊,中]/牛燕雄,汪岳峰,雷鸣,张雏(军械工程学院光学与电子工程系.河北,石家庄(050003)),陈德伟(广州军区军械雷达修理所光学室.广东,广州(510000))//光电子·激光.-2000,11(6).-620-622通过测量和分析物镜、像增强器和目镜等的性能参数,对微光夜视仪的最大作用距离进行估算。
基金Project supported by National Natural Science Foundation of China （50837005, 5110 7099）, Foundation of the State Key Laboratory of Electrical Insulation for Power Equip- ment （EIPE09203）.
文摘With its unique features, photoconductive semiconductor switch (PCSS) is generally recognized today as a promising power electronic device. However, a major limitation of PCSS is its surprisingly low voltage threshold of surface flashover (SF). In this paper, an experimental study of surface flashover of a back-triggered PCSS is presented. The PCSSs with electrode gap of 18 mm are fabricated from liquid encapsulated czochralski (LEC) semi-insulating gallium arsenide (SI-GaAs), and they are either un-coated, or partly coated, or en- tirely coated PCSSs with high-strength transparent insulation. The SF fields of the PCSSs are measured and discussed. According to the experimental results, the high-dielectric-strength coating is efficient in both reducing the gas desorption from semiconductor and increasing the SF field: a well-designed PCSS can resist a voltage up to 20 kV under the repetition frequency of 30 Hz. The physical mechanism of the PCSS SF is analyzed, and the conclusion is made that having a channel structure, the SF is the breakdown of the contaminated dielectric layer at the semiconductor-ambient dielectric interface. The non-uniform distribution of the surface field and the gas desorption due to thermal effects of semiconductor surface currents are key factors causing the SF field reduction.
基金supported by the National Natural Science Foundation of China (10804016)the Electromagnetic Pulse Technology and Investigation (RY0504)
文摘Starting from the uniform disk current model, an analytical solution for the electromagnetic pulse axial energy radiation is derived and a physical meaning then given to the axial energy propagation characteristics of a unit antenna. From this solution, a point-source approximation model in the time domain is introduced. Parameters such as the energy propagation characteristics and beamwidth of the electromagnetic pulse beam radiating from arrayed antenna are analyzed theoretically. An arrayed transient electromagnetic pulse generator is developed incorporating a 23×16 ultra-wideband tapered slot antenna integrated with a Blumlein formation line and photoconductive semiconductor switch. Experiments performed over a 2.5 km range confirm that the arrayed transient electromagnetic pulse can propagate in free space with the specified waveform. Moreover, the field components can be superposed in phase, and the radiation beam can be focused into a single pulse. Results from calculations are in agreement with experimental results within the measurement uncertainties.
