共查询到19条相似文献,搜索用时 93 毫秒
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本文简述了获得 Chauvenet系数拟合公式的必要性;给出依据最小二乘原理获得该拟合公式的方法.结果为:当4≤ N≤ 70时,ω1=0.359In(N-1.5)+1.193;当70≤N≤2000时,ω2=0.2688 In(N—20)+ 1.63.在给定范围内,低端和高端的拟合值均准确到0.01. 相似文献
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高离化态离子能级一般拟合公式的提出及研究 总被引:8,自引:3,他引:5
分析J.-F.Wyart和I.Matsushima等人提出的拟合公式,考虑高Z离子的量子电动力学效应,综合提出能级的一般拟合公式:ΔE=A+BZC+CZ2C+DZ3C+EZ4C+FZ5C+GZ6C+HE7C+Higherorderterms。并以类Ni为例探讨了此公式的完善性和合理性。 相似文献
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本文首次报道了Y3Ga,O23:Cr3+晶体的色散,根据Sellmeier公式拟合了该晶体的色散曲线.折射率的计算值与实验值符合很好. 相似文献
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传统的空间掩盖效应是采用韦伯(Weber)定律来描述的,然而该定律仅考虑了明视觉区,对较弱或较强的光强均不合适。为了更好地描述空间掩盖效应,本文利用信号处理方法,给出了一种新的拟合公式。实验用不同模型拟合Konig与Brodhun的实验数据,证实了提出的模型均方根误差仅为0.0102,小于传统的Weber定律、Weber定律的优选表达式、Guilford模型,以及Chen模型。结果表明,提出的拟合公式在更宽的光强范围内都能与数据很好地拟合,可更广泛地用于工程实践。 相似文献
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实验研究了盐Langmuir-Blodget单分子层膜在不同基频光和倍频光偏振态组合(s→p,p→p和45°→s)情况下的透射光学二次谐波产生(SHG),并利用有关透射方向SHG理论公式进行了曲线拟合.结果发现,随着入射角的增大,拟合曲线与实验点存在较大的偏移.这是因为忽略了基频光和倍频光在作为LB膜衬底的玻璃基板内的多次反射造成的.研究了理论拟合曲线和实验结果偏移的主要原因.并给出了考虑多次反射最低阶修正后的理论公式和拟合曲线.研究结果表明:进行变入射角情况下的透射SHG研究时,特别是当测量涉及到s偏振态时,如果要固定探测装置的位置不变,那么玻璃内的多次反射必须加以考虑
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正交多项式最小二乘曲线拟合法求光源色温的经验公式 总被引:4,自引:0,他引:4
本文报道用正交多项式最小二乘曲线拟合法,首次获得精确计算光源色温的经验公式Tc,色温Tc≤2000K,2000~20000K和10000~100000K范围的标准偏差分别为1.852×10-2,1.439×10-3和3.536×10-3。应用拟合公式计算了黑体辐射、标准光源以及重组日光的色温值,结果令人满意。 相似文献
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V. P. Afanas’ev D. S. Efremenko A. V. Lubenchenko 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2011,5(2):375-382
The reconstruction of inelastic scattering cross sections faces two problems: the measured signal (energy spectrum) is a multiple
scattering signal; the inelastic energy loss is nonuniform over the target depth. In this paper, we present a method for numerical
reconstruction of cross sections from characteristic energy loss spectra, which efficiently solves both problems within a
multilayer model. It is shown that the inverse problem of cross section extraction in the three-layer model is ill-conditioned,
and the method is practically inapplicable to the three-layer model. The direct numerical reconstruction method yields a strongly
“noised” result and can be applied only to obtain a priori information on the inelastic cross section form for further fitting.
Using a combination of two methods, inelastic scattering cross sections were reconstructed for aluminum from characteristic
energy loss spectra at probe beam energies of 5 and 40 keV. It is shown that ionization in solids should be described as a
local process and as a collective one using the dispersion formula similarly to the case of excitation plasmons. 相似文献
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Junwei Min Baoli Yao Peng Gao Baiheng Ma Shaohui Yan Fei Peng Juanjuan Zheng Tong Ye Romano Rupp 《Optik》2012,123(17):1525-1529
An on-axis polarization phase-shifting digital holographic microscope, based on a normal upright optical microscope, is constructed to quantitatively measure both the amplitude and phase distributions of specimen. The condenser lens and microscope objective employed in the object beam path enhance the illumination and magnification of the image, however, they induce additional phase aberration of the object wave. The physical formation of the phase aberration is theoretically analyzed, and a formula for the object wave front involving the phase aberration in the CCD plane is derived. The phase aberration can be eliminated in the reconstruction procedure by measuring a specimen-free hologram and then fitting the aberration phase with a least square ellipsoidal model to determine the parameters of the system. This phase aberration compensation procedure also reduces some of noises in the reconstructed phase of the specimen. The practicability of this method is demonstrated by a test experiment on microlenses. 相似文献
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目前计算机配色中,拟合样与标准样的色差小时配方偏差较大,打样结果不理想,难以预测准确配方。在光学模型Stearns-Noechel模型的基础上进行算法优化。利用两个样品的分光反射率数据相等,则两个样品必然等色的特性,改进计算机配色算法程序中的判别条件,即通过MATLB编程计算,在区间[0 1]中,每间隔0.001,循环未知参数M值,选择全光谱反射率数据偏差最小时的参数M值计算拟合配比,代替色差最小时的参数M值计算拟合配比,并分别计算拟合样与标准样的相对配方偏差进行对比。结果表明,选择全光谱反射率数据偏差最小时参数M值对应的拟合配方,一次色的平均配方相对偏差为0.560,二次色为0.346;选择色差最小时参数M值对应的拟合配方,一次色的平均配方相对偏差为0.723,二次色为0.383;两种方法对比,可以看出无论是一次色还是二次色,优化算法后拟合样品与标准样品的配方相对偏差都比选择色差最小时对应的的相对配方偏差小,即优化后的拟合配方更加接近真实配方,配色精确度得到明显提高,有利于减少后期打样次数,提高配色效率。 相似文献
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天体光谱信号的连续谱归一化新方法 总被引:1,自引:1,他引:0
采用事先扣除强谱线的策略,提出小波变换与样条拟合相结合的方法进行连续谱拟合,并通过对实际光谱的试验,与较常用的连续谱拟合方法进行比较,结果表明文章提出的方法有明显的优越性。另外,针对多项式拟合等方法得到的连续谱可能会出现负值的情况,推导出有效的连续谱校正公式。 相似文献
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真空下气-固界面热适应系数的数值计算 总被引:2,自引:0,他引:2
根据热适应系数的理论研究成果,结合国外学者的部分实验数据,对气-固界面热适应系数的主要影响因素进行定性的讨论;同时在S.Song和M.M.Yovannovich的公式基础上,最小二乘法拟合国外学者低温下实验测量的热适应系数,采用C语言编程算出拟合公式中的参数,分析拟合公式α=aFM/(b+M)+2.4μ(1-F)/(1+μ)2,F=exp(c(T-T0)/T0)中的参数a,b,c的特性;数值计算迭代收敛和拟合公式的计算误差在±20%以内表明:数值拟合公式可用在工程上计算热适应系数,S.Song和M.M.Yovannovich的公式可数值拟合低温下不同气-固界面的热适应系数的计算公式。 相似文献
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Scattering neutrons are one of the key factors that may affect the images of fast neutron radiography. In this paper, a mathematical model for scattered neutrons is developed on a cylinder sample, and an empirical formula for scattered neutrons is obtained. According to the results given by Monte Carlo methods, the parameters in the empirical formula are obtained with curve fitting, which confirms the logicality of the empirical formula. The curve-fitted parameters of common materials such as 6LiD are given. 相似文献
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Scattering neutrons are one of the key factors that may affect the images of fast neutron radiog- raphy. In this paper, a mathematical model for scattered neutrons is developed on a cylinder sample, and an empirical formula for scattered neutrons is obtained. According to the results given by Monte Carlo methods, the parameters in the empirical formula are obtained with curve fitting, which confirms the logicality of the empirical formula. The curve-fitted parameters of common materials such as <'6>LiD are given. 相似文献