共查询到20条相似文献,搜索用时 15 毫秒
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The scattering of a spherical wave by a static irregular dielectric surface, separating two subspaces with dielectric constant close to the permittivity of free space, is investigated by the Kirchhoff method. The irregularities of the surface — large-scale with small angles of inclination, and their heights are distributed according to a normal law. Self-shadowing and the set of spots associated with scattering on such a surface are taken into account. The polarization matrix of second moments of the components of the scattered field is calculated. The dependence of the matrix elements on the statistical parameters of a randomly irregular surface are discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 7–10, May, 1974. 相似文献
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一种内混合气溶胶粒子模型光散射的等效性 总被引:1,自引:0,他引:1
以包含灰尘、黑碳和水三种成分的单分散内混合初次气溶胶为例,利用消光、吸收、散射效率因子和不对称因子,探讨了以等效折射率描述具有不同成分的内混合气溶胶粒子系统的适用性。结果表明,在尺度参数为0.1~25时不同半径比下,消光、吸收和散射效率因子的等效性较好,相对误差分别在3%、3%和4%以内;不对称因子的等效性相对稍差,相对误差在13%以内。当半径比a/b小于1/5,即内混合体中所含灰尘和黑碳较少时,等效折射率实部和虚部值基本可以确定,而不必考虑尺度参数的影响。用除散射相函数之外的其他光学量来等效时,较为容易找到等效的气溶胶粒子。 相似文献
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Farafonov V. G. Il’in V. B. Prokopjeva M. S. Tulegenov A. R. Ustimov V. I. 《Optics and Spectroscopy》2019,126(4):360-366
Optics and Spectroscopy - We have constructed a spheroidal model to solve the problem of light scattering by nonspherical particles. The semiaxes of the model spheroid are determined based on the... 相似文献
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Jacqueline B. A. Card Alan R. Jones Hua Zhao 《Particle & Particle Systems Characterization》1996,13(2):137-142
An instrument is proposed for the visualisation and measurement of mixtures of small and large particles. The original concept was to use spectral extinction for sub-micron particles and scattering patterns for larger sizes. However, the former method is sensitive to the refractive index, which may be unknown or vary with wavelength in an unknown way. The experiments demonstrated this to be a problem. The forward scatter, on the other hand, is not so sensitive to this. It is shown here that the combination of scattered intensity as a function of both angle and Wavelength provides scatter diagrams for which there is good agreement between theory and experiment. The influence of quite small volume fractions of particles as small as 0.3μm mixed with 90μ particles is easily seen. The scatter diagrams suggest the use of image analysis for size measurement and quality control. 相似文献
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Farafonov V. G. Ustimov V. I. Prokopjeva M. S. Tulegenov A. R. Il’in V. B. 《Optics and Spectroscopy》2018,125(6):971-976
Optics and Spectroscopy - To describe light scattering by small nonspherical particles, we have constructed an ellipsoidal model using a quasistatic approximation. The semiaxes of the model... 相似文献
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V. I. Radchenko 《Journal of Experimental and Theoretical Physics》2000,91(4):682-690
A closed variant of the Born approximation for calculating differential scattering cross sections in ion-atom collisions is developed. An expression in terms of the matrix elements J ij with respect to the single-electron states of the atom is found for the matrix element describing the target atom in the formula for the differential cross section. The matrix elements J ij are averaged over the relative orientation of the momentum transferred in the collision and the symmetry axis of the electronic orbitals of the target atom, using the single-electron Rutaan-Hartree-Fock wave functions. The algebraic representation of the matrix elements J ij makes it possible to perform calculations for atoms with any value of Z. The model developed is used to calculate the cross sections σΣ and characteristic scattering angles θc for the process of electron loss by H? ions with energy E = 0.1–100 MeV in targets consisting of atoms with Z = 2–54. It is shown that σΣ ∝ E ?1 and θc ∝ E ?1/2 for all Z, and for fixed E the behavior of σΣ(Z) and θc(Z) is determined by the order of filling of the electronic shells of the target atoms (the ionization potential). The computational results are analyzed and compared with the experimental data and the results of other calculations. 相似文献
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白光LED智能调光数学模型 总被引:2,自引:2,他引:0
LED灯的光通量不仅受电流的影响,还受到结温变化的影响。针对传统LED调光存在只改变电流大小而忽略结温变化对光通量影响所存在的不足,结合LED结温和管脚温度存在特定的关系,利用实验装置采集HL001WY型Ga N基白光LED在不同管脚温度和正向电流下的光通量实验数据并进行二次项趋势回归,利用定标和归一化方法建立光通量、电流以及管脚温度三者变化关系的数学模型。计算结果表明,利用该方法建立的模型得到的计算数值与实验实际测量值的相对误差小于4.5%。 相似文献
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Domenico Finco 《Reports on Mathematical Physics》2007,59(3):379-388
We discuss the asymptotic wave function of a quantum system in ?3 composed by heavy and light particles, in the case where the light particles are in scattering states and no interaction is assumed among particles of the same kind. We first review a recent result concerning the case of K heavy and N light particles, where the one-particle potential acting on each heavy particle decays at infinity. Then we consider the case of one light particle interacting with a system of harmonic oscillators and prove the same kind of result following, with some modification, the proof of the previous case. A possible application to the analysis of the scattering of a light particle from condensed matter is also outlined. 相似文献
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Yu. V. Ivanov A. R. Karimov L. N. Pyatnitsky A. P. Seryakov V. A. Shcheglov 《Journal of Russian Laser Research》2005,26(5):363-372
Transmission of laser radiation in human blood plasma diluted with physiological solution is studied. Comparison with scattering
in pure physiological solution is made. General and individual optical characteristics of blood plasma from different patients
are established. 相似文献
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In the analysis of electromagnetic scattering by distributions of small dielectric particles an approximation to the scattered field can be obtained by representing the electrical interaction of the particles in terms of the dipole moments of the individual particles. The calculation of the moments necessitates the solution of certain static scattering problems, and this becomes numerically difficult when the particles are thin. An integral equation formulation of the static scattering problem specialized to the case of thin planar dielectric plates is presented, along with an efficient numerical routine. Dipole moments are obtained over a range of permittivities for plates with several thicknesses and a variety of cross-sectional shapes, and the shape dependence is discussed. 相似文献