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We develop a new calibration method in lab by measuring the absolute spectral irradiance responsivity of Sun photometer sun channel. The absolute power responsivity of Sun photometer is obtained when a white laser double monochromator system serve as a source, and a standard transfer detector calibrated against cryogenic absolute radiometer is assembled to measure the absolute power of laser beam. The effective area of aperture is measured through laser raster scanning method, and the relative spectral irradiance responsivity of the corresponding channel is obtained by using tungsten-halogen lamps double monoehromator system. On the basis of the above results, the top of the atmosphere responsive constants V0 (500, 675, and 870 nm) are obtained by integration with extraterrestrial solar spectral irradiance data. Comparing the calibration results with that of CIMEL, France in November 2011, the relative differences are 4.38%, 2.23%, and 2.45%, respectively. The calibration uncertainty reaches to 2.048×10^-2, which shows a remarkable consistency with the Langley plot method. Further, our scheme can overcome the limits of space and atmospheric conditions which are only available at a high-altitude calibration site in particular date. The advantages lie in not only shortening the experiment period but also being of high precision. This new scheme definitely plays an important role in supporting the current and future sun photometry calibration activities which are significant to earth observation. 相似文献
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为在相关光子定标技术工程化过程中选择合适的泵浦机制及相位匹配模式,开展了基于连续和脉冲激光的相关光子比对实验.采用355nm连续激光泵浦偏硼酸钡晶体产生相关光子对,对晶体吸收、透射损耗以及光学元件透过率进行测量和修正,同时使用基于时间幅度转换的符合测量方法,得到单光子探测器量子效率为59.15%.利用518nm脉冲激光泵浦周期极化磷酸钛氧钾晶体,采用准相位匹配技术获取相同波段的相关光子,基于时间幅度转换的符合测量方法得到单光子探测器量子效率为59%.比对实验结果,两套定标装置方法的测量结果之差在0.25%以内,主要误差来源于单光子探测器的响应非线性、光路透过率修正误差和单光子探测量子效率面非均匀性.实验结果验证了相关光子定标技术可随时随地复现的优点,以及相关光子定标结果不受泵浦机制差异和实验装置差异的影响,可为相关光子技术工程化中的激光器工作模式和相位匹配方式的选择提供参考依据. 相似文献
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采用355nm连续激光泵浦BBO晶体产生参量下转换效应,搭建了相关光子辐射定标实验装置,使用时间数字转换和时间幅度转换两种符合测量方法进行比对测量,定标了不同光子速率下雪崩光电二极管在737nm波段的探测效率,分析了在高光子计数率下死时间和后脉冲等因素对符合测量选取符合门宽和意外符合的影响,比较了不同光子计数速率的测量结果并分析符合测量的修正因素,修正后两种测量结果的相对偏差优于0.25%.采用时间间隔技术测量了不同光子计数率的后脉冲概率,为提高单光子探测器的计数精度和相关光子定标的精度提供依据. 相似文献
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采用分光光度法来检测完整细胞内H2O2酶的活性,以实现细菌的快速检测。由于细菌(本研究以E.coli DH5α为模型)内含有H2O2酶,当往菌液中加入H2O2时,H2O2会在胞内H2O2酶的作用下分解,其分解过程遵循一级动力学反应。通过测量该反应中H2O2在240nm处吸光度的变化,可以得出该一级反应的速率常数,从而获悉菌液的浓度。结果表明:大肠杆菌单位细胞浓度酶活为4.2×10-13L/(s·cell),其速率常数与浓度在5.7×106~5.7×107cfu/mL范围内呈现良好的线性关系,检出限为5.7×106cfu/mL。本方法是一种检测细菌总数的快速方法,测试时间为5~10min。 相似文献