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针对长焦距测量中被测透镜像差引入的焦距测量误差提出了一种校正方法。传统长焦距测量中使用高斯公式来计算被测透镜的焦距值,未考虑被测透镜像差引入的误差。在采用发散光作为测量光束的大口径光学元件焦距测量中,该误差成为了影响测量精度的重要因素。详细分析了基于发散光和泰伯效应的长焦距测量法,利用数值方法获得了误差修正值,并与Zemax的仿真结果进行了对比。利用Visual C++编程,实现了测量结果的自动校正功能。对名义焦距值为13500mm和31251mm透镜的测量数据分别进行校正后,其相对于名义焦距值的测量精度分别优于0.007%和0.022%。将校正后的测量精度与干涉仪法的测量精度进行了对比,结果充分说明了该方法是可靠和有效的。 相似文献
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Structural,electronic,and magnetic properties of transition-metal atom adsorbed two-dimensional GaAs nanosheet 下载免费PDF全文
By using first-principles calculations within the framework of density functional theory,the electronic and magnetic properties of 3d transitional metal(TM) atoms(from Sc to Zn) adsorbed monolayer Ga As nanosheets(Ga As NSs) are systematically investigated.Upon TM atom adsorption,Ga As NS,which is a nonmagnetic semiconductor,can be tuned into a magnetic semiconductor(Sc,V,and Fe adsorption),a half-metal(Mn adsorption),or a metal(Co and Cu adsorption).Our calculations show that the strong p–d hybridization between the 3d orbit of TM atoms and the 4p orbit of neighboring As atoms is responsible for the formation of chemical bonds and the origin of magnetism in the Ga As NSs with Sc,V,and Fe adsorption.However,the Mn 3d orbit with more unpaired electrons hybridizes not only with the As 4p orbit but also with the Ga 4p orbit,resulting in a stronger exchange interaction.Our results may be useful for electronic and magnetic applications of Ga As NS-based materials. 相似文献
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本文对亚乙烯基-乙炔异构化过程开展了高精度量子动力学理论研究. 使用我们建立和发展的高效量子动力学理论方法,进行了大规模的并行计算,其中根据双氢转移的特征定制了高效的基函数. 计算得到了关于A''1和B''2对称性的亚乙烯基振动态以及离域态,并与最近的cryo-SEVI实验光谱进行了比对和分析. 计算所得能级与cryo-SEVI光谱实验值吻合很好,两者之间的差异或者与实验测量的误差大小类似,或者不大于30 cm-1(与亚乙烯基剪形振动模式相关的振动态除外). 本文还揭示和报道了一种特殊的态,称之为异构态,其特征是在亚乙烯基和乙炔区域都有很大的几率分布. 本文首次报道了若干以亚乙烯基特征为主导的振动态,本文的研究将会有助于深入认识双氢转移过程. 相似文献
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We propose a new quantum watermarking scheme based on threshold selection using informational entropy of quantum image. The core idea of this scheme is to embed information into object and background of cover image in different ways. First, a threshold method adopting the quantum informational entropy is employed to determine a threshold value. The threshold value can then be further used for segmenting the cover image to a binary image, which is an authentication key for embedding and extraction information. By a careful analysis of the quantum circuits of the scheme, that is, translating into the basic gate sequences which show the low complexity of the scheme. One of the simulation-based experimental results is entropy difference which measures the similarity of two images by calculating the difference in quantum image informational entropy between watermarked image and cover image. Furthermore, the analyses of peak signal-to-noise ratio, histogram and capacity of the scheme are also provided. 相似文献
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提出了顶空-气相色谱-质谱法(HS-GC-MS)测定卫生巾中55种挥发性有机物含量的方法。将卫生巾样品剪碎,采用自动顶空进样方式,于110℃下低速振荡15 min,用DB-624色谱柱(60 m×0.25 mm, 1.40μm)分离和质谱检测样品中55种挥发性有机物,外标法定量。结果表明,55种挥发性有机物的质量分数均在0.080~2.000μg·g-1内与其对应的峰面积呈线性关系,测定下限(10S/N)为0.000 3~0.031 0μg·g-1。按照标准加入法进行回收试验,回收率为81.3%~119%,测定值的相对标准偏差(n=6)均小于9.0%。方法用于实际卫生巾样品的分析,结果显示多种挥发性有机物被检出,1,3,5-三甲苯的检出率高达89.3%,氯甲烷检出量高达10.688μg·g-1。 相似文献
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