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《Journal of Modern Optics》2013,60(8):907-921
In the framework of the eikonal picture, the Glauber expression for the scattering amplitude is extended to the whole angular domain and to intermediate and even low energies (under some restrictions on the scattering potential) in the context of light scattering by large particles. Differential cross sections illustrate clearly the difference between Glauber's results and those given here. 相似文献
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Li J.L.-W. Zhong-Cheng Li Hao-Yuan She Zouhdi S. Mosig J.R. Martin O.J.F. 《Nanotechnology, IEEE Transactions on》2009,8(5):617-626
Light or electromagnetic wave scattered by a single sphere or a coated sphere has been considered as a classic Mie theory. There have been some further extensions that were made further based on the Mie theory. Recently, a closed-form analytical model of the scattering cross section of a single nanoshell has been considered. The present paper is documented further, based on the work in 2006 by Alam and Massoud, to derive another different closed-form solution to the problem of light scattered by the nanoshells using polynomials of up to order 6. Validation is made by comparing the present closed-form solution to the exact Mie scattering solution and also to the other closed-form solution by Alam and Massoud. This study is found to be, however, more generalized and also more accurate for the coated spheres of either tiny/small or medium sizes than that of Alam and Massoud. Therefore, the derived formulas can be used for accurately characterizing both surface plasmon resonances of nanoparticles (of small sizes) or nanoantenna near-field properties (of medium sizes comparable with half wavelength). 相似文献
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由于传统累积量反演算法计算结果随相关时间的变化有较大的波动,提出一种新的累计量算法,此方法直接利用光子相关光谱函数作为目标函数进行反演,减少相关时间选择对测量结果的影响.在介绍传统累积量光子相关光谱法颗粒粒径分布反演算法的基础上,引入以光子相关光谱函数作为累积量算法的目标函数的反演算法,利用实验平台对90 nm的乳胶颗粒进行测量.运用实验获得的相关函数数据研究两种累积量算法和相关时间之间的关系,实验结果表明,采用传统累计量算法其结果受相关时间影响较大,而本文所提算法稳定性好,在较长相关时间范围内基本不受相关时间影响. 相似文献
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论文在Mie理论基础上,给出了球形粒子对平面偏振光的散射强度和散射系数公式,利用连分式递推算法进行了编程计算,重点对1.06μm激光的模拟结果进行了分析.从得到的散射图像可以看出,散射强度角分布与散射粒子尺度有密切关系,随着粒子尺度的逐渐增大,散射光强主要集中到前、后向散射方向,集中的角度越来越窄,模拟结果明显出现了散射强度最弱的极值角,且该极值角随粒径的增大而增大,最后逼近90°方向.散射强度角分布与波长有关,当它们在同一数量级时达到最大值,与散射粒子折射率无关.该递推算法因为每一步计算都是独立的,与前后项的准确性没有关系,不存在不稳定、发散等情况,能够计算粒径参数范围从10-4开始,对上限不受任何限制. 相似文献
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Abstract The optical analogue of a formula by Reading and Bassichis for the backscattering of a high-energy scalar wave by a square-well potential has been examined. In optical scattering, this corresponds to the problem of the back-scattering of light by a homogeneous spherical particle. Numerical checks with the Mie theory are presented for various values of the refractive index and size parameter. The formula is found to reproduce some scattering features extremely well for intermediate-size soft particles. 相似文献
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In a continuous development for more than three decades, dynamic light scattering (DLS) has evolved into a versatile and powerful technique for the determination of transport and other thermophysical properties of fluids. The success is founded on its application in a macroscopic thermodynamic equilibrium, i.e., without the need for employing external gradients, to determine a large variety of properties, which can be derived, in some instances even simultaneously, by an appropriate experimental approach and a corresponding signal analysis. The principles, essential features, and variants of the technique are reviewed, and a survey on the determination of various desired transport and thermophysical properties is given, both for the application of light scattering from bulk fluids and for the variant of surface light scattering (SLS). The stage of development and the corresponding uncertainties are discussed for the measurement of the individual quantities, and the performance of the method is demonstrated by representative experimental results for relevant fluids. 相似文献
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Akhlesh Lakhtakia George W. Mulholland 《Journal of research of the National Institute of Standards and Technology》1993,98(6):699-716
Smoke agglomerates are made of many soot sphcres, and their light scattering response is of interest in fire research. The numerical techniques chiefly used for theoretical scattering studies are the method of moments and the coupled dipole moment. The two methods have been obtained in this tutorial paper directly from the monochromatic Maxwell curl equations and shown to be equivalent. The effects of the finite size of the primary spheres have been numerically delineated. 相似文献
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Abstract The validity of the optical analogue of Chen and Hoock's formula for high-energy backward potential scattering has been examined in the context of optical scattering. Numerical comparisons are presented for the exactly soluble case of homogeneous spheres for various refractive-index-size-parameter domains. 相似文献
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P.N. Segrè W. Van Megen P.N. Pusey K. Schätzel W. Peters 《Journal of Modern Optics》2013,60(9):1929-1952
Abstract The design, alignment and operation of improved two-colour dynamic light scattering equipment which effectively suppresses multiple scattering and allows the study of the Brownian dynamics of optically turbid samples is described. The technique operates by cross-correlating scattered light of two different colours. With the appropriate scattering geometry, only singly scattered light contributes to the time-dependent part of the measured intensity cross-correlation function thus allowing straightforward interpretation of the data. To demonstrate the performance of the instrument we have studied various colloidal suspensions. Although dilute enough that free diffusion of the particles can be assumed, the samples ranged from quite transparent to distinctly turbid. We have confirmed that the measured cross-correlation functions accurately reflect only single scattering even in the presence of strong multiple scattering. 相似文献
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采用表面活性剂辅助的溶胶-凝胶法制备了粒径在200~900nm之间可调控的球形TiO2颗粒. 基于SEM、TEM、XRD、氮气吸附-脱附等分析手段, 系统研究了不同种类和链长的非离子表面活性剂ODA、Span-80、F-127、PEG系列对颗粒粒径和分散性的影响, 结果表明TiO2颗粒的形貌、粒径及尺寸分布与所加入表面活性剂分子的空间位阻有关. 对于同一种类型的表面活性剂, 所加入分子的空间位阻越大得到颗粒的形貌越规则、颗粒的粒径越小、单分散性越好. BET分析表明, 加入F-127及PEG-20000所得到的TiO2颗粒经500℃处理后具有介孔结构, 平均孔径分别为3.4和2.6nm. 相似文献
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Germer TA 《Applied optics》2001,40(31):5708-5710
A recent paper by Karabacak et al. [Appl. Opt. 39, 4658 (2000)], which discussed the scattering from rough surfaces in directions out of the plane of incidence, exhibited an error in the derivation of a polarization factor. An asymmetry in the scattering function for directions out of the plane of incidence and for circularly polarized incident light is predicted by the correct derivation of this factor and can be observed in their data. 相似文献
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Xiaogang Lin Rongrong Wang Yongcai Guo Chao Gao Xiaoen Guo 《International Journal of Thermophysics》2012,33(10-11):1795-1800
Primary liver cancer is one of the highest mortality malignant tumors in the world. China is a high occurrence area of primary liver cancer. Diagnosis of liver cancer, especially early diagnosis, is essential for improving patients?? survival. Light scattering and measuring method is an emerging technology developed in recent decades, which has attracted a large number of biomedical researchers due to its advantages, such as fast, simple, high accuracy, good repeatability, and non-destructive. The hypothesis of this project is that there may be some different light scattering information between hepatoma cells and hepatocyte. Combined with the advantages of the dynamic light scattering method and the biological cytology, an experimental scheme to measure the light scattering information of cells was formulated. Hepatoma cells and hepatic cells were irradiated by a semiconductor laser (532?nm). And the Brookhaven BI-200SM wide-angle light scattering device and temperature control apparatus were adopted. The light scattering information of hepatoma cells and hepatic cells in vitro within the 15°C to 30°C temperature range was processed by a BI-9000AT digital autocorrelator. The following points were found: (a) the scattering intensities of human hepatic cells and hepatoma cells are nearly not affected by the temperature factor, and the former is always greater than the latter and (b) the relaxation time of hepatoma cells is longer than that of hepatic cells, and both the relaxation time are shortened with increasing temperature from 15°C to 25°C. It can be concluded that hepatoma cells could absorb more incident light than hepatic cells. The reason may be that there exists more protein and nucleic acid in cancerous cells than normal cells. Furthermore, based on the length relaxation time, a conclusion can be inferred that the Brownian movement of cancer cells is greater. 相似文献