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The ionicity of oxide and β- and β″-Al2O3 crystals is identified via Lorentz–Lorenz molar refractivity. The investigation was extended to sodium gallates, the refractivity and average refractive index of which are estimated. 相似文献
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Ge-Sb-Se硫系玻璃被认为是极佳的红外传输材料和有潜力的非线性光学材料.在光学设计中,玻璃的线性折射率(n)及其热光系数(ζ)是关键技术参数.以预测和调控Ge-Sb-Se玻璃的n和ζ为目的,考察了玻璃的n,ζ,密度(d)和体积膨胀系数(β)与化学参数dSe和拓扑网络结构参数r的内在联系.研究发现,玻璃的n随d的增加而增大;ζ随β的增大而近似线性减小;β随dSe的减小或r的增大而减小;当Ge含量固定时, d随dSe的减小或r的增大而增大,当Sb含量固定时, d在dSe=0时具有最小值.基于实测d和n,拟合获得了Ge, Sb和Se元素在2—12μm波段的摩尔折射度(R_i),分别为R_(Ge)=10.16—10.50 cm~3/mol,RSb=16.71—17.08 cm~3/mol和RSe=11.15—11.21 cm~3/mol,根据d和R_i计算得到的n与实测值的偏差小于1%.基于实测ζ和β,拟合得到了Ge, Sb和Se元素在2—12μm波段的摩尔折射度温度系数(φ_i),分别为φ_(Ge)=21.1—22.6 ppm/K,φ_(Sb)=7.2—8.4 ppm/K和φ_(Se)=90.2—94.2 ppm/K,根据β和φ_i计算得到的ζ与实测值的偏差小于6 ppm/K. 相似文献
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This paper addresses the probability of atmospheric refractivity estimation by using field measurements at an array of radio receivers in terms of angle-of-arrival spectrum.Angle-of-arrival spectrum information is simulated by the ray optics model and refractivity is expressed in the presence of an ideal tri-linear profile.The estimation of the refractivity is organized as an optimization problem and a genetic algorithm is used to search for the optimal solution from various trial refractivity profiles.Theoretical analysis demonstrates the feasibility of this method to retrieve the refractivity parameters.Simulation results indicate that this approach has a fair anti-noise ability and its accuracy performance is mainly dependent on the antenna aperture size and its positions. 相似文献
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《Physics and Chemistry of Liquids》2012,50(6):785-801
The apparent molar volume (?V), viscosity B-coefficient and molar refraction (RM) have been determined of L-valine in aqueous solution of LiCl, NaCl and KCl at 298 K, 303 K and 308 K from density (ρ), viscosity (η) and refractive index (nD) measurements, respectively. The limiting apparent molar volumes (?V0) and experimental slopes (SV*) derived from the Masson equation have been interpreted in terms of solute–solvent and solute–solute interactions, respectively. The viscosity data were analysed using the Jones–Dole equation and the derived parameter B has also been interpreted in terms of solute–solvent interactions in the solutions. Molar refraction (RM) has been calculated using the Lorentz–Lorenz equation. 相似文献
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光学材料的折射率和色散系数对光学系统成像影响极大,如折射率对球差等单色像差的影响极为敏感,而色散系数则对色差有直接影响。本文将以具体产品为例.分析光学常数对折射物镜的影响。 相似文献
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合成了基于烷基咪唑的乳酸离子液体[C4mim][Lact](1-丁基-3-甲基咪唑乳酸盐),并用1HNMR和DSC作了表征.由于乳酸离子液体和水易形成氢键,用通常的办法很难除去乳酸离子液体中的杂质水.为了排除杂质水的干扰,应用了标准加入法,配制一系列含有已知微量水的乳酸离子液体样品,在308.15~343.15K温度范围,用重量法测定了这些样品的密度,用最大气泡法测定了表面张力,用折光率确定了摩尔极化度,然后外推得到无水离子液体数据.在这些实验数据基础上,利用等张比容的加和性,估算了乳酸离子液体同系物[Cnmim][Lact](n=2,3,4,5,6)的表面张力、折射率、摩尔极化度、汽化焓和热膨胀系数,与实验数据相比有较好的一致性. 相似文献
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This paper addresses the problem of estimating lower
atmospheric refractivity under the nonstandard propagation conditions
frequently encountered in low altitude maritime radar applications.
The vertical structure of the refractive environment is modeled by
using a five-parameter model, and the horizontal structure is modeled
as range-independent. The electromagnetic propagation in the
troposphere is simulated by using a split-step fast Fourier
transform based on parabolic approximation to the wave equation. A
global search marked as a modified genetic algorithm (MGA) for the 5
environmental parameters is performed by using a genetic algorithm
(GA) integrated with a simulated annealing technique. The retrieved
results from simulated runs demonstrate the ability of this method
to make atmospheric refractivity estimations. A comparison with the classical GA
and the Bayesian Markov Chain Monte Carlo (Bayesian-MCMC) technique
shows that the MGA can not only shorten the inverse time but also
improve the inverse precision. For real data cases, the inversion
values do not match the reference data very well. The
inverted profile, however, can be used to synoptically describe
the real refractive structure. 相似文献
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