The influence of a charged domain wall on the formation of the induced domain structures in congruent x-cut lithium niobate crystals (LiNbO₃) is studied. By diffusion annealing in air ambient near Curie temperature, as well as infrared annealing in oxygen-free ambient bi- and multidomain ferroelectric structures containing charged domain walls «head-to-head» and «tail-to-tail» were formed. By Kelvin probe mode of atomic force microscopy (AFM) surface potential near the charged domain walls was investigated. We studied surface needle-shaped induced microdomains which were formed in a vicinity of the domain boundary and far from it by applying of voltage to the cantilever being in a contact with the surface of the sample. Dependence of morphology of the induced domain structure on the crystal’s electric conductivity was demonstrated. Screening effect of charged «head-to-head» domain wall on a shape and size of the domain, that was induced near the boundary is shown. We described partition of the single needle-shaped domains formed by AFM cantilever to several microdomains having a shape of several beams based in a common nucleation point. We found an influence of the charged domain wall on the topography of the samples, which consisted in the appearance of a long groove corresponding to the domain boundary after the reducing annealing.

The method of two-crystal X-ray diffractometry is used to control the quality and perfection of monocrystalline silicon obtained by implantation of hydrogen ions and subsequent thermal annealing, which is used in a number of semiconductor technologies. The principal feature of this approach is the ability to quickly obtain reliable experimental results, which was confirmed in this paper by the use of X-ray topography. The presented data provide information on the state of the disturbed layer of silicon crystals of n-type conductivity (ρ = 100 Om ⋅ cm) by orientation (111), 2 mm thick, implanted by protons with energy E = 200, 300, 100 + 200 + 300 keV, dose D = 2 ⋅ 1016cm-2 and subjected to subsequent thermal treatment in the temperature range T from 100 to 900 °С. We have established a non-monotonic dependence of the integral characteristics of the disturbed layer, namely the average effective thickness Leff and the average relative deformation ∆а/а, on annealing temperature, with the maximum level of distortion in the field of temperature ∼300 °С, using the method of integral characteristics. Obtained data allowed to assess the general condition of disturbed layer during thermal treatment.

Scintillation materials that can convert absorbed high-energy particles into photons of visible radiation find many applications, in particular in modern methods of medical imaging. Gd3Al2Ga3O12 : Ce is promising single crystal for use as a detecting crystal element of the positron emission tomographs due to its unique properties: high density, high light output, radiation hardness, etc. However, its scintillation kinetics currently limit the use of this crystal. Changing of these kinetics by codoping becomes a priority task, which is considered in many papers. The literature data analysis showed that the optical characteristics of such codoped crystals were not well enough studied or were not investigated at all. In this regard, the spectral dependences of transmission, absorption and reflection are measured using optical spectroscopy for Gd3Al2Ga3O12:Ce, Gd3Al2Ga3O12 : Ce,Ca and Gd3Al2Ga3O12 : Ce,Zr. Dispersion dependences of refractive in dices are obtained by approximating the refractive indices measured using the Brewster method. The approximation was carried out using the Cauchy equation. The material constants of this equation are estimated.

In practical application of crystals in optoelectronics and laser technology it is necessary to know the direction of optical axes and types of oscillatory centers, which is a relevant and necessary condition. In this paper, the infrared spectra of transmission and absorption of hexagonal crystals of lithium iodate α-LiIO3, grown by open evaporation in H2O and D2O solutions, as well as natural lamellar crystals of phlogopite and muscovite monoclinic crystal are investigated. The band gap width of the investigated crystals is determined by transmission spectra. In the absorption spectra there were determined activation energy and wavelength of the oscillatory centers that are associated with the vibrations of protons, hydronium ions Н3О+, protium H+, OH groups and molecules HDO. The good correlation of the parameters of infrared spectra with the spectra of thermally stimulated depolarization currents and NMR spectra has shown. The possibility of diagnostics of types of oscillatory centers by means of infrared spectra is considered, which also allows to find out the direction of optical axes. The obtained results allow to use IR spectra to determine not only the types of vibrational centers, but also the presence of anisotropy of the crystal lattice of the studied crystals.

The features of the development of the electronic path of the TV channel of the television type detector (TTD) are considered. It is noted that the mode of binning (addition of pixels) is the most difficult in technical implementation.
Calculations are made to improve the mathematical model for the computer detector television type. The parameters of the analytical formula valid for proton energies from 30 to 250 MeV, based on the combination of functions of the parabolic cylinder, consistent with numerical methods and new experimental data, are determined. A list of theoretical papers describing the modified Bragg curve is given.
Offers the possibility of a new approach to the description of dose field Bragg peak consisting in the application of the so-called «full experience» when the experimentally measured characteristics of the dose distribution of a system of equations in which the measured values are presented as a function of the so-called «amplitude dose field». The «amplitude dose field» are determined from the solution of this system of equations. The «amplitude dose field» depend on the z coordinates in the water phantom where, the z-axis of the beam direction and after determining the amplitudes from the system of equations described-certain amplitudes are used to quickly predict the measured characteristics of the dose distribution. The combination of the adaptive electronic pathway working independently without the participation of the operator during the experiment on the calibration of the accelerator and in determining the experimentally measured characteristics of the dose distribution, allows on-line to prepare the therapeutic accelerator «Prometheus» for a session with the patient.

Nanocrystalline tungsten oxide (WO₃), indium oxide (In₂O₃), cobalt oxide (Co₃O₄) and mixed composites with different WO₃—In₂O₃ and WO₃—Co₃O₄ ratios were obtained by the sol-gel method after calcination of xerogels at 400—600 °C. The morphology, phase composition, and structural features of the materials obtained were studied by X-ray diffraction, infrared spectroscopy, and scanning electron microscopy. The increase in the gas sensitivity of the joint composition compared to the initial oxides can be explained by a decrease in the crystallite size and an increase in the specific surface, as well as by the dependence of the surface state of the grains on the composition. The highest sensory response to nitrogen dioxide in both compositions lies in the range of 130—150 °C, and to carbon monoxide, above 230 °C. Low-power planar nitrogen dioxide sensors with a sensitivity of << 1 ppm and power consumption ≤ 85 mW were produced.

Юрию Николаевичу Пархоменко — выдающемуся ученому в области физико-химии и технологии неорганических материалов, физического материаловедения, исследования состава, структуры и свойств материалов, главному редактору журналов «Известия высших учебных заведений. Материалы электронной техники» и Modern Electronic Materials — 70 лет.