Добірка наукової літератури з теми "Indicatrix of scattering"

The work within the scalar theory of Kirchhoff, solved the problem of scattering of laser light rough surface for the simulation which used two-dimensional modified Weierstrass function with a finite number of harmonics. Based on the analytical solution found numerically calculated scattering indicatrix laser fractal surfaces of several types for different angles of incidence and created a catalog of various specific types of scattering surfaces based on the Weierstrass function and the corresponding three-dimensional scattering indicatrix ln < rs > . It is shown that when scattering light by a surface of a fractal relief, the law of mirror reflection is violated, and the scattering image contains bursts of intensity in different directions.

A method for the experimental determination of elastic scattering an electron by an atom indicatrix from probe measurements of the scattered electrons distribution function in the transit mode low voltage beam discharge. The Boltzmann kinetic equation was solved by the expansion method in series by the number of collisions, and the scattered part of the electron distribution function was experimentally determined by the planar one-sided probe method, which was previously developed by the authors for beam discharge studies. The method was tested in a plasma of a low-voltage He beam discharge. A good agreement between the experimentally measured elastic electron scattering indicatrix at an energy of 30 eV and known data on the differential cross section is obtained. It is shown that for the implementation of the developed method for determining the elastic scattering of an electron beam by atoms indicatrix, no a priori data required.

A technique for research the spatial structures of the condensed phase grains in heterogeneous smoky plasma by determining the laser scattering indicatrix modulated with a frequency of 60 kHz in three spectral intervals was developed. An experimental stand was created to register the laser scattering indicatrix on the wavelengths of 808 nm, 630 nm and 532 nm in the scattering angles range from 0 to 170º with a measurement time of 3 seconds. A program of registration and processing of measurement results on a computer has been developed. Tests of the experimental complex on the flame of metalized fuel compositions were carried out.

Дисертаційна робота присвячена розробці методу фотометричного аналізу біологічних середовищ шляхом розширення простору визначення їх оптичних властивостей, що дозволило одночасно врахувати характеристики відбитого та пропущеного середовищем оптичного випромінювання в межах повного тілесного кута. У роботі розроблено методики реалізації математичного базису просторової фотометрії біологічних середовищ за принципами визначення інтенсивності розсіяння по паралелях (кільцевих смугах) та меридіанах (перетинах). Запропоновані схемо-технічні рішення двох- та восьми-канальної інформаційно-вимірювальних систем для просторової фотометрії за перетинами, реалізовані на рівні експериментальних установок. Розроблено програмне забезпечення фотометричного паралельного аналізу, що дозволяє досліджувати індикатриси розсіяння за перетинами. Проведено аналіз індикатрис розсіяння лазерного випромінювання товщинними зразками м’язових тканини на різних довжинах хвиль та з різним розміщенням волокон. Здійснено перехід від індикатриси розсіяння товщинними зразками до фактору анізотропії однократного розсіяння. Доведено ідентичність експериментально-визначених величин оптичних коефіцієнтів дифузного відбиття та повного пропускання та визначених за результатами Монте-Карло моделювання з використанням усередненої за перетинами величини фактору анізотропії однократного розсіяння.
The thesis is devoted to developing the method of photometric analysis of biological media by expansion the space of definition their optical properties. That made possible the simultaneously consider the characteristics of the optical radiation, reflected and transmitted by biological media, within the full solid angle. In the work the main methods of solution the basic equation of radiative transfer theory in problems of optical biomedical diagnostics, were analyzed. Thus, the main attention focused on optical parameters of biological media: scattering (μs), absorption (μa) coefficients, and the anisotropy factor of single scattering (g), which are responsible for spatial distribution of scattered radiation by normal and pathology tissues or media (first order approximation, diffuse approximation, small angle approximation, flux models, Monte Carlo method). Conditions of use depending the type of biological media are described. The phase functions of single scattering (Mie, Henyey-Greenstein, Gegenbauer kernel, Delta-Eddington, Eddington), which used to describe the propagation the optical radiation in different types of biological media, were considered. Systematized the methods and tools of biophotonics with the possibilities of spatial-oriented analysis of radiation, scattered by sample of biological media, organs and body parts. Goniometric and spherical types of experimental setup are the most appropriated types that can used for spatial photometry. Photometric image of varying thickness samples of biological media by ellipsoidal reflectometry were received. Based on experimental research, the axial asymmetry of anisotropy of scattering by porcine and chicken muscle tissues of varying thickness in vitro at a wavelength of 632.8 nm was found. The influence of anisotropy of scattering on accuracy of determination the optical coefficients of diffuse reflection and total transmission by method Monte Carlo was demonstrated. Study of spatial anisotropy scattering by method of photometry was suggested. On this basis, has developed methods of implementing of the mathematical basis of spatial photometry of biological media by determining the scattering intensity along parallels (circular bands) and meridians (sections). The mechanism of the transition from experimentally determined indicatrix of scattering of thick sample to the anisotropy factor of single scattering by designed methods is proposed. The proposed scheme-technical versions of information-measurement system for spatial photometry along sections with two and eight channel, which were realized in experimental setups of goniometric and spherical type. The features of element synthesis, exploitation and calibration of setups are described. The interfaces and methods of application of developed software for parallel photometric analysis "IMSOB" and "IMSOB-2", to support research the scattering indicatrix along sections in reflected or transmitted light for two- and eight-channel systems respectively are given. The method of sample preparation of biological media and features of experiment for different experimental setups of spatial photometry are given. The methodology of preparation the biological samples used for research in this paper were detail described. The analysis of the indicatrix of laser light scattering by thick samples of muscle tissue at different wavelengths with transverse and longitudinal placement of fibers was made. The data obtained by method of spatial photometry, which realized the principle of analyses of the sections. Experimental studies conducted on goniometric type setup. For phase function of single scattering Henyey-Greenstein, modified by isotropic component in each sections, the transition from indicatrix scattering of thick sample to the single scattering anisotropy factor g was made. Identity of experimentally-determined values of the optical coefficients of diffuse reflection and total transmission and determined by the results of Monte Carlo simulation using the average values by sections of the anisotropy factor of single scattering are approved.
Диссертация посвящена разработке метода фотометрического анализа биологических сред путем расширения пространства определения их оптических свойств, что позволило одновременно учесть характеристики отраженного и пропущенного средой оптического излучения в пределах полного телесного угла. В работе разработаны методики реализации математического базиса пространственной фотометрии биологических сред по принципу определения интенсивности рассеяния по параллелям (кольцевым полосам) и меридианам (сечениям). Предложены схемотехнические решения двух- и восьмиканальной информационно-измерительных систем для пространственной фотометрии по сечениям, реализованные на уровне экспериментальных установок. Разработано программное обеспечение фотометрического параллельного анализа, позволяющее исследовать индикатрисы рассеяния по сечениям. Проведен анализ индикатрис рассеяния лазерного излучения толщинными образцами мышечных тканей на различных длинах волн и с разным размещением волокон. Осуществлен переход от индикатрисы рассеяния толщинных образцов к фактору анизотропии однократного рассеяния. Доказана идентичность экспериментально определенных величин оптических коэффициентов диффузного отражения и полного пропускания и определенных по результатам моделирования Монте-Карло с использованием усредненной по сечениям величины фактора анизотропии однократного рассеяния.

Optical beams can be controlled by manipulating the refractive indices and absorption coefficients with applied electric fields. In communication systems electro-optic effects are used in phase and amplitude modulation, in beam deflectors, and in tunable filters. Three such effects are illustrated in Fig. 28.1. Lead lanthanum zirconate titanate (PLZT) is a transparent electroceramic that can be prepared in several different ferroelectric forms with large electro-optic coefficients. When prepared in a normal ferroelectric form it can be used in two different ways. A light-tunable shutter is constructed by coating a multidomain ceramic of PLZT with a photoconducting layer and transparent electrodes. A bias voltage on the electrodes is transferred to the ceramic when the photoconductor is illuminated. The electric field alters the domain structure and the degree of light scattering, controlling the intensity of light. Fully poled ferroelectric ceramics exhibit the linear electro-optic effect Using planar electrodes the PLZT is poled perpendicular to the optical beam. Polarizer and analyzer are positioned in the ±45◦ positions, and light intensity is controlled by altering the birefringence with an electric field. The third experiment utilizes a pseudo-cubic PLZT composition with a large quadratic electro-optic effect. No poling is required in this case. With polarizer and analyzer again in the ±45◦ positions, the transmitted light intensity is proportional to E2 rather than E. Linear and quadratic electro-optic coefficients are defined in terms of the fieldinduced changes in the optical indicatrix: . . . Bij(E) − Bij(0) = Δ

The paper deals with the elastic light scattering on spherical absorbing particles phenomenon and the method of its quantitative description in the framework of the theory of G. Mi. An algorithm for calculating the scattered radiation relative intensity in an arbitrary direction has been developed and a modeling 3D scattering indicatrices program has been obtained. The models of 3D indicatrix scattering laser linearly polarized radiation on transparent and absorbing spherical particles are presented. The analysis of the light absorption effect on the relative angular distribution shape of the scattered radiation intensity on particles of various sizes has been carried out.The dy namics of the scattering 3D indicatrix shape on an absorbing particle as its radius changes has been visualized. The potential areas of the program practical application have been identified. The factors limiting to use program for calculations of scattering on real particles systems has been revealed.

The main purpose of this study was to confirm operability and effectiveness of the complex methods developed for theoretical prediction and experimental-computational determining some properties of modern highly porous materials, used as thermal protection shields in objects of space engineering, power engineering, etc. Them concern Fibrous Materials (FM), Open-Cell Reticulated Foams (OCRF) etc. The basis for the method proposed is in the combination of Direct Mathematical Simulation (DMS) for global structure of the complex irregular systems, which have the property of local regularity and Inverse Heat Transfer Problem (IHTP) methods. This approach makes possible to obtain and to predict such properties as radiation and molecular thermal conductivities, energy accommodation coefficient, complex refractive index, scattering indicatrix, scattering and absorption factors, etc. Such problems are of great practical importance in the study of material properties.