http://dspace.nbuv.gov.ua:80/handle/123456789/114627 2026-04-17T21:08:43Z http://dspace.nbuv.gov.ua:80/handle/123456789/119062 Influence of absorption level on mechanisms of Braggdiffracted x-ray beam formation in real silicon crystals Klad'ko, V. P.; Grigoriev, D.O.; Datsenko, L.I.; Machulin, V.F.; Prokopenko, I.V. The methods of numerical calculations based on the formulae of the X-ray dynamic scattering theory by real crystals and of the Takagi-Topin equations were used for investigation of the basic regularities of inherent to the Bragg diffraction in conditions of a strong and weak absorption. The mechanisms of profile formation of a spatial intensity distribution of diffracted beams depending on an energy of radiation and on structural perfection parameters of crystals are discussed. The formulae for an analytical description of spatial intensity distribution profiles which take into account the dynamical corrections (coefficients of extinction) for coherent and incoherent components of the total reflectivity were used. 1999-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/117956 Thermoelasticity in Ge due to nonuniform distribution of doping impurity studied by light polarization modulation technique Serdega, B.K.; Venger, Ye.F.; Nikitenko, Ye.V. Volume-gradient photovoltage and birefrigence caused by a difference of main mechanical stress components have been studied in the Ge-monocrystal with step-like distribution of the doping impurity concentration, N. The qualitative agreement between the function obtained by integration of the spatial dependence of the anisotropy and of the coordinate dependence of the photovoltage was observed. Using this fact, the conclusion is made that the features of thermoelastic mechanical stress can be distribution of expressed by the dependence |σz - σy| ~ d²N/dz². Remove selected 1999-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/117955 Influence of temporal parameters of laser irradiation on emission spectra of the evaporated material Zabello, E.; Syaber, V.; Khizhnyak, A. The results of study of the emission spectra of metals excited by laser pulses bursts under atmospheric conditions are presented. It is demonstrated that the area responsible for the atom irradiation of evaporated substance is essentially distant from that of the continual spectrum irradiation. As a result, the sensitivity of the qualitative analysis increases. For quantitative analysis it is necessary to select the analytical lines differing from those used for spark or arc emission analysis. 1999-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/117954 Characteristics of thermal lens induced in active rod of cw Nd:YAG laser Khizhnyak, A.; Galich, G.; Lopiitchouk, M. The structure of thermal lens induced in active rod of cw Nd: YAG laser was investigated using the Mach-Zehnder interferometer and electronic speckle pattern interferometry (ESPI) system. It is shown that thermal lens has weak aberrations and coincides to the with that of parabolic lens. The se aberrations play role of perturbations and lead to the oscillation of all transversal modes that exceed the threshold of oscillation. It is shown that the change of the pumping level leads to thermal lens displacement and the changes of its principal planes. 1999-01-01T00:00:00Z