共查询到19条相似文献,搜索用时 187 毫秒
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针对光散射细胞微粒测量中真实形体细胞的取向对测量结果的影响问题,基于Rayleigh-Debye-Gans理论和双椭球核式(CEM)模型在应用中的差异,建立了CEM的修正模型(MCEM),根据此模型系统讨论了细胞在不同入射角变化情况下其光散射强度分布所产生的变化,得到了不同入射角下有核细胞光散射强度分布与有核细胞相关物理特征量的动态响应关系;此外,对有核细胞光散射强度分布进行拟合,得到了有核细胞光散射强度分布函数。误差分析表明:拟合结果可有效地应用于真实细胞光散射测量中的数值反演计算。 相似文献
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给出了一种结合射线追踪和蒙特卡罗方法计算含核粒子光散射的方法,内核粒子可以为稀疏分布也可为浓密分布.粒子外边界的反射和折射由射线追踪方法计算,而粒子内部的多次散射过程由蒙特卡罗方法模拟;当内核粒子为浓密随机分布时,其单次散射特性由基于静态结构因子(static structure factor)的浓密介质光散射理论计算.最后讨论了含核椭球粒子模型的单次散射特性.
关键词:
射线追踪技术
蒙特卡洛方法
光散射
椭球粒子 相似文献
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王淑平 《中国光学与应用光学文摘》2006,(1)
Q632006010797细胞形体和胞质厚度变化对光散射法测量细胞大小分布的影响=Influencing upon light scattering for variety ofcell′s body and cytoplast′s thickness in measurement oftheir distribution[刊,中]/王亚伟(江苏大学理学院.江苏,镇江(212013)),蔡兰…∥中国激光.—2005,32(9).—1300-1304针对真实细胞与细胞球形模型在实际光散射法检测中的差异,根据细胞的类别特征,建立了有核细胞的双椭球模型取代了细胞的球形模型;引入形体参数物理特征量和胞质厚度特征参数,以瑞利-德拜-甘斯(Rayleigh-Debye-Gans)理论为基础,系统讨论… 相似文献
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采用声散射理论和目标强度近似模型评估法对黄海鲤鱼(Engraulis japonicus)的声散射特征和目标强度进行了数值计算与评估研究。散射模型由鱼鳔模型和鱼体模型两个部分构成,其中鱼鳔采用充满气体的椭球体模型,鳔除外的鱼体采用充满液体的椭球体模型。理论数值计算所需参数取自全长12.6cm的鲤鱼个体,其鱼鳔尺寸利用X光照片测得。平均目标强度利用模型算得的不同角度下的声散射强度与鲲鱼倾角分布函数的卷积计算,其中倾角(度)的分布函数设为N(-3.9,12.8^2)。结果显示,鲲鱼对声波的散射具有明显指向性;在38kHz和120kHz工作频率下,鲲鱼的最大背向目标强度分别为-41.2dB和-39.5dB,有效平均目标强度分别为-48.0dB和-51.5dB,与实测结果吻合较好。另外还对鲲鱼的反向散射指向性特征、目标强度的频率特征以及鱼鳔对鲲鱼整体目标强度的贡献等进行了分析与讨论。以上研究表明,模型法作为现场测定研究方法的重要补充和认知鱼类声学散射特性的有效途径,可在我国鱼类目标强度的研究中发挥重要作用。 相似文献
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动态光散射技术在微米与亚微米级颗粒系粒径分析领域中具有广泛应用,但缺乏非球形颗粒系粒径分布(PSD)的反演模型和算法,限制了其在生物医疗等领域中的应用。基于机器学习方法,设计了基于广义回归神经网络(GRNN)的PSD反演模型和算法,可应用于多角度动态光散射法的粒径分析场景中。以生物医疗领域中的双凹圆饼形和椭球形血红细胞作为典型的非球形颗粒物模型,通过仿真实验测试了所设计的算法。实验结果表明,与传统的正则化Tikhonov算法相比,所设计的反演算法粒径分析准确性更好且耗时更短。对多角度动态光散射法中的散射角度数量进行了仿真实验。结果表明,仅使用2个散射角度处获得的数据依然能实现非球形颗粒系粒径分布的准确反演。 相似文献
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基于广义Mie理论, 研究了椭球粒子对在轴入射的拉盖尔-高斯光束的散射特性. 通过局域近似法求解椭球坐标系中的波束因子, 计算得到了波束因子之间满足的普遍关系. 对散射强度随椭球粒子不同尺寸参数和扁圆程度的变化特性进行了数值计算, 并针对不同拓扑荷时的散射强度进行了对比分析. 结果表明: 当椭球粒子尺寸在与入射光波长可比拟的范围内变化时, 散射强度随尺寸参数的增大而增大, 随椭球长短轴之比和拓扑荷的增大而减小. 本文的理论研究能够为拉盖尔-高斯光束在粒径测量、大气激光通信、 大气遥感等领域的应用提供更准确的粒子模型和参考价值.
关键词:
椭球粒子
拉盖尔-高斯光束
波束因子
散射强度 相似文献
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Alexey Zharinov Alexander Shvalov Konstantin Semyanov Valeri Maltsev 《Journal of Quantitative Spectroscopy & Radiative Transfer》2006,102(1):121-128
This study describes the measurement of light scattering of human mononuclear blood cells, the development of an appropriate optical model for those cells, and solution of the inverse light-scattering problem. The angular dependency of light-scattering intensity of mononuclear blood cells was experimentally measured by means of scanning flow cytometry. A sphere consisting of several concentric homogeneous layers with different refractive indices was tested as an optical model for mononuclear blood cells. A five-layer model has given the best agreement between experimental and theoretical light-scattering profiles. The inverse light-scattering problem was solved for a five-layer model with an optimization procedure that allows one to retrieve cell parameters: cell size relates to the outer diameter of the fifth layer; size of the nucleus relates to the outer diameter of the third layer. Mean values of cell size, nuclear size, refractive indices of nucleus and cellular cytoplasm were determined for blood monocytes and lymphocytes. 相似文献
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We describe a new design for a microscope-based static light-scattering instrument that provides simultaneous high-resolution images and static light-scattering data. By correlating real space images with scattering patterns, we can interpret measurements from heterogeneous samples, which we illustrate by using biological tissue. 相似文献
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We perform field-based angle-resolved light-scattering measurements from single live cells. We use a laser interferometer to acquire phase and amplitude images of cells at the image plane. The angular scattering spectrum is calculated from the Fourier transform of the field transmitted through the cells. A concurrent 3D refractive index distribution of the same cells is measured using tomographic phase microscopy. By measuring transient increases in light scattering by single cells during exposure to acetic acid, we correlate the scattering properties of single cells with their refractive index distributions and show that results are in good agreement with a model based on the Born approximation. 相似文献
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A theoretical model for calculating the motion dynamics of the particles of different light-scattering mechanisms in the energy inhomogeneous optical field is suggested. The direct relationship between the motion velocity of the tested particles in the created field and the degree of coherence of mutually orthogonal linearly polarized plane waves is demonstrated. 相似文献
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This paper describes a method and apparatus for the simulation of various experimental situations which are often required for the solution of problems of optics and spectroscopy of light-scattering media. The depth distribution of brightness within light-scattering materials, their albedo, indicatrix, etc., can be investigated. The investigations can be made at any optical depths and with different underlying surfaces. It is also possible to simulate horizontally in-homogeneous and vertically stratified media, which it has not been possible to simulate before. The brightness indicatrices obtained on a model of the earth's atmosphere with broken cloud of different density, stratification, extent of cloud cover, and above different underlying surfaces are illustrated.Translated from Izvestiya VUZ. Fizika, No. 1, pp. 34–42, January, 1972. 相似文献
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Dynamic light scattering in localized coherence volumes 总被引:2,自引:0,他引:2
We introduce a novel light-scattering technique for investigating the dynamics of random media with a broad range of optical densities. By use of the spatial coherence properties of a single-mode optical fiber and the temporal coherence of a broadband source, the measurement volume is isolated at the end of the optical waveguide. Optical mixing between the fluctuating scattered light and the Fresnel-reflected field at the fiber-medium interface is analyzed directly in the frequency domain. The unique characteristics of this new technique are discussed in the context of simultaneous measurement of average scatterer size and concentration in dense colloidal suspensions. 相似文献
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Tetrahymena pyriformis is a single cell eukaryote that can be modified to respond to magnetic fields, a response called magnetotaxis. Naturally, this microorganism cannot respond to magnetic fields, but after modification using iron oxide nanoparticles, cells are magnetized and exhibit a constant magnetic dipole strength. In experiments, a rotating field is applied to cells using a two-dimensional approximate Helmholtz coil system. Using rotating magnetic fields, we characterize discrete cells’ swarm swimming which is affected by several factors. The behavior of the cells under these fields is explained in detail. After the field is removed, relatively straight swimming is observed. We also generate increased heterogeneity within a population of cells to improve controllability of a swarm, which is explored in a cell model. By exploiting this straight swimming behavior, we propose a method to control discrete cells utilizing a single global magnetic input. Successful implementation of this swarm control method would enable teams of microrobots to perform a variety of in vitro microscale tasks impossible for single microrobots, such as pushing objects or simultaneous micromanipulation of discrete entities. 相似文献
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Cheng-Yang LiuWei-En Fu Tzeng-Yow LinChi-Sheng Chang Jay-San Chen 《Optics and Lasers in Engineering》2011,49(1):145-151
Characterizing surface roughness in nanoscale nondestructively is an urgent need for semiconductor and wafer manufacturing industries. To meet the need, an optical scatter instrument in bidirectional ellipsometry has been developed for characterizing nanoscale surface roughness, in particular, on the wafers after chemical-mechanical polishing. The polarized angular dependence of out-of-plane light-scattering from nanoscale surface roughness is analyzed and characterized. These analysis and characterization results show strong correlations of surface roughness and angular dependence of bidirectional ellipsometric parameters for full field light-scattering. The experimental findings prove good agreement with theoretical predictions for different surface roughnesses. As a result, the nanoscale surface roughness can be accurately measured and characterized by the angular dependence and the polarization of light scattered from surface. 相似文献