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A method is proposed to optimize the recording structure of the photorefractive volume grating to compensate high spatial frequency in the distorted wavefront by optical phase conjugation. Based on the coupled-wave equation, the diffraction efficiency of the recorded grating formed by the scattered beams in different recording structures is simulated. The theoretical results show that the recorded modulations with high spatial frequency can be significantly improved in the small recording angle. In the experiment, three recording structures with the recording angles of 7.5°, 30°, and 45° are chosen to verify the compensation effect. Compared with the reconstructed image in the large recording angle of 45°, the signal to noise ratio of the image recorded at 7.5° increases to 3.2 times of that at 45°. 相似文献
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引言进口UBI_2万用电源是用于光谱分析较先进的光源。与早期的可控硅直流电孤发生器相比,具有多种激发方式。可同时快速分析多种元素。我们通过对其功能的反复试验,选择最佳工作条件,实现了摄谱曝光时间自动控制。激发方式的选择UBI_2电源发生器和它自带的可调火花 相似文献
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开环磁流体发电工质——燃气等离子体的化学平衡组成及热力和电物理性质 总被引:1,自引:0,他引:1
本文叙述了添加有碱金属作为电离种子的燃气等离子体的化学平衡组成,平衡态和“冻结态”热力和电物性的计算方法和结果。在计算中考虑了23种成分,20种热电性质。并讨论了这些性质对磁流体发电机特性的影响。 计算的条件和范围是: 燃烧剂:柴油。 氧化剂:富氧空气,其中氧重量比φ=0.2315(空气)—1.0(纯氧)。 余氧系数α_∑:0.7—1.1 氧化剂预热温度T_p:从常温—2000K。 种子碳酸钾水溶液浓度m:(?)从0.5—1.0(干粉)。 燃气含钾率ε:从0.01—0.03(重量比)。 压力p:从0.6—8.0公斤/厘米~2。 温度T:从2000K—绝热燃烧温度,步长100K 磁感应强度B:2或5韦泊/米~2。 计算结果已被应用于磁流体发电机的设计、理论分析和等离子体诊断。 相似文献
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