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131.
132.
A compact and simple design for an LDA-end-pumped intracavity doubling high-power blue laser with a composite Nd:YAG laser on the 4F3/2 to 4I9/2 laser transition in a flat-curved cavity is demonstrated. The nonlinear crystal used in the experiment is an LBO crystal cut for phase-matching type I. Through the thermo-lensing effect of the laser crystal at high-pumped power, the optimum mode-matched and efficient intracavity doubling are realized at the same time. The maximum output power at 473 nm was 600 mW when the absorbed, pumped power of 15 W, and the optical-to-optical conversion efficiency is 4%. The stability of blue output power is 3.2% within 2 h. 相似文献
133.
基于OpenGL的DEM地形可视性分析算法研究 总被引:2,自引:0,他引:2
针对规则网格模型的DEM可视性问题,提出了一种基于仰角坡度比较法的LOS方法,以LOS视线为基准,根据DEM地形实际的高程和坡度值来判断其是否可视,并给出了可视化区域的确定方式.利用OpenGL图形库提供的网格化方式创建可视区域,给出了VC++开发环境下的可视化区域绘制程序. 相似文献
134.
对教师和学生在使用普通高中化学课程标准实验教材人教版<物质结构与性质>的情况进行调查,并根据调查结果,对实施新课程标准后,教师的教和学生的学两方面的现状进行了分析. 相似文献
135.
A laser-diode-pumped Nd:YVO4 orange solid-state laser is described in this paper. The fundamental wavelengths at 1064 and 1342 nm oscillate simultaneously and generate the 593.5 nm wavelength by intracavity sum-frequency mixing in a KTP crystal using type II phase matching. The noise characteristic of laser output has been measured and analyzed at different pumping powers. The relationship between the amplitude noise of sum-frequency mixing output and the longitudinal modes of fundamental frequency has been investigated. The results show that the sum-frequency mixing output has low noise if one of the fundamental wavelengths is single longitudinal mode. The experiment shows that amplitude noise of the intracavity sum-frequency mixing laser is lower than that of intracavity frequency doubled laser with the same structure. 相似文献
136.
Adaptive filtering for color filter array demosaicking. 总被引:2,自引:0,他引:2
Nai-Xiang Lian Lanlan Chang Yap-Peng Tan Vitali Zagorodnov 《IEEE transactions on image processing》2007,16(10):2515-2525
Most digital still cameras acquire imagery with a color filter array (CFA), sampling only one color value for each pixel and interpolating the other two color values afterwards. The interpolation process is commonly known as demosaicking. In general, a good demosaicking method should preserve the high-frequency information of imagery as much as possible, since such information is essential for image visual quality. We discuss in this paper two key observations for preserving high-frequency information in CFA demosaicking: (1) the high frequencies are similar across three color components, and (2) the high frequencies along the horizontal and vertical axes are essential for image quality. Our frequency analysis of CFA samples indicates that filtering a CFA image can better preserve high frequencies than filtering each color component separately. This motivates us to design an efficient filter for estimating the luminance at green pixels of the CFA image and devise an adaptive filtering approach to estimating the luminance at red and blue pixels. Experimental results on simulated CFA images, as well as raw CFA data, verify that the proposed method outperforms the existing state-of-the-art methods both visually and in terms of peak signal-to-noise ratio, at a notably lower computational cost. 相似文献
137.
本文求解了一个圆形夹杂物对裂纹尖端应力场的影响,计算了反平面切变问题经典的应力场和应力强度因数,进而求得了非局域应力场,得到非奇异的裂纹尖端应力的解析表达式,讨论了解的应用。
关键词: 相似文献
138.
140.
流动注射催化光度法测定痕量亚硝酸根 总被引:6,自引:0,他引:6
采用流动注射技术与催化光度法相结合,研究了亚硝酸根催化溴酸钾氧化维多利亚绿G的高灵敏度褪色反应,用自制的微机化流动注射分析仪能准确控制时间,优化了实验条件,建立了测定痕量亚硝酸根的流动注射催化光度方法。分析速度每小时80次,克服了催化反应时间难以控制引起的方法精密度,准确不谪的弱点。亚硝酸根在0.0-0.3mg/L范围内,回归方程斜率为0.708;亚硝酸根在0.3-2.0mg/L范围内,回归方程斜率为0.339,方法用于直接测定水中的亚硝酸根获得满意结果。 相似文献