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针对高功率射频板条CO2激光器铜电极表面放电氧化、受射频放电的电子溅射,致使电极表面不光滑,辉光放电不均匀,光波导损耗严重等问题。利用Al2O3波导介质膜具有的反常色散效应、耐高温能力强的特点,采用磁控溅射镀膜技术对激光器电极表面先镀Al,而后阳极氧化获得Al2O3波导介质膜。分析了磁控溅射工艺对膜层结构的影响,测量了镀膜电极对CO2激光的反射率,并进行了放电实验检测。结果表明,溅射功率为250 W时可得到致密的镀膜层结构;厚度6μm的Al2O3薄膜,对波长10.6μm的CO2激光波导反射率最高达75%;电极镀膜后激光器输出功率在占空比为30%时为700 W,占空比为60%时达到了1300 W。 相似文献
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介绍了用于风切变测量的激光雷达外差探测系统,阐述了其工作原理,根据CO2雷达系统与Ho:YAG雷达系统相关参数进行信噪比模拟和风速误差对比,模拟结果表明:波长2.1 μm的Ho:YAG雷达和10.6 lμm CO2都适合机载低空风切变探测.通过对比,无论系统效率还是衰减率,Ho:YAG的性能都更为优良、误差更小、探测距离更远. 相似文献
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介绍了用于风切变测量的激光雷达外差探测系统,阐述了其工作原理,根据CO2雷达系统与Ho:YAG雷达系统相关参数进行信噪比模拟和风速误差对比,模拟结果表明波长为2.1μm的Ho:YAG雷达和波长为10.6μm CO2雷达都适合机载低空风切变探测。通过对比表明Ho:YAG雷达的性能更为优良,误差更小,探测距离更远。 相似文献
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Enhanced Performance of Phase Change Memory Cell Element by Initial Operation and Non-Cumulative Programming
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A phase change memory (PCM) device, based on the Ge2Sb2Te5 (GST) material, is fabricated using the standard 0.18-μm CMOS technology. After serials of detailed experiments on the phase transition behaviors, we find that the RESET process is strongly dependent on the state of the inactive area and the active area affects the SET process dramatically. By applying a 5-mA current-voltage (I — V) sweep as initial operation, we can reduce the voltage drop beyond the active area during the RESET process and the overall RESET voltage decreases from 3 V plus to 2.5 V. For the SET operation, a non-cumulative programming method is introduced to eliminate the impact of randomly formed amorphous active area, which is strongly related to the threshold switching process and SET voltage. Combining the two methods, the endurance performance of the PCM device has been remarkably improved beyond 1 × 106 cycles. 相似文献
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