A kinetic model for the low-pressure oxygen positive column is presented and discussed. The model is based on the electron Boltzmann equation and the rate balance equations for the dominant heavy-particle species, which are solved simultaneously in order to take into account the coupling between the electron and the heavy-particle kinetics. The effects of vibrationally excited molecules, dissociated atoms and metastable states on the electron kinetics are analysed in detail. The predicted populations of O2(X3 Sigma ), O2(a1 Delta ), O(3P), and O- are shown to agree satisfactorily with previously reported measurements. A combination of this kinetic model with the continuity and transport equations for the charged species e, O-, and O2+ is shown to provide characteristics for the maintenance field that agree reasonably well with experiment.

We investigated the kinetics of conversion of hemin to β-hematin in aqueous-acetate medium in absence and in presence of two concentrations of chloroquine by using eleven reported kinetic equations. The two best kinetic equations are the combination of order 1 and Avrami and the combination of second order and logistic equations, based on the statistical parameters variance and overall errors. The best fitted equations are composed of two terms from which we model the formation of β-hematin as the result of two processes: the availability of reactive precursors and the formation of nucleation and growth sites. The crystals exhibit needle-like morphologies of about 760 nm long and 140 nm wide. However, the increment of chloroquine favors the formation of crystal twinning with non-homogenous distribution, crystals with lower sizes of similar heights and widths, and crystals symmetrically tapered at the ends of the needles. The lattice volumes, obtained from Rietveld analysis of powder X-ray diffraction patterns, were not regularly affected by chloroquine. The main IR absorption bands did not appreciably change in positions nor in intensities with varying chloroquine concentration. However, important changes were observed in the 2000-4000 cm-1 region. We used Density Functional Theory calculations to understand these changes.

The results of experimental studies of the effect of degradation of macroscopic charge transport in ensembles of close-packed anatase nanoparticles under long-term action of a constant electric field are presented. The degradation is presumably due to the increasing degree of blocking of statistically independent conduction channels formed in ensembles of particles under the field action. A phenomenological model is considered for estimating the number of active conduction channels in an ensemble of particles near the percolation threshold in the system. Keywords: nanoparticles, anatase, charge transfer, percolation threshold.

Purpose. Analysis of status and chemical composition of non-metallic inclusions of raw railway truck axle shafts steel using electron microscopy and X-ray spectral microanalysis for the improvement of the throughout technology of the axles production. Methodology. Study of phase composition and type of non-metallic inclusions in axles shaft steel was carried out with modern equipment and method of X-ray spectral microanalysis for quantitative and qualitative data. Findings. The analysis of the elements on chemical composition on EA1N steel and of non-metallic inclusions on physical and mechanical properties of railway axles made by rolling of continuous cast billt of 470 mm diameter. The types and composition of non-metallic inclusions were studied with electron microscopy and X-ray spectral microanalysis. Results can be applied for improvement of steel refining and alloying technology for railway wheel axles production. Originality. There were discovered the original data about the types and chemical compositions of nonmetallic heterophasic inclusions in railway axis metal using the electronic microscopy and X-ray microanalysis. The obtained research results about formations of multiphase inclusions were proved using the phase equilibrium charts consiolering oxide, oxide-sulphide mineral phases. Practical value. The results of electron microscopy and X-ray spectral microanalysis are important to understand and improve the throughput technology of refining and alloying of EA1N steel for railway axle shafts. Keywords: railway axle, railway truck, axle shaft, steel chemical composition, continuous casting billet, mechanical properties, non-metallic inclusions

The results of a study of the galvanomagnetic properties of indium arsenide grown by liquid-phase epitaxy are presented. It is shown that the use of the rare earth element holmium in the growth of InAs epitaxial layers makes it possible to reduce the electron concentration by two orders of magnitude to n=2.1·1015 cm-3 at T=77 K. This effect is due to the gettering of shallow background impurities with the formation of their compounds in the melt. With an increase in the holmium content of more than 0.12 mol.% the concentration of current carriers in the material begins to increase, while mobility decreases due to the influence of VAs-Ho donor centers. This method of gettering is promising for obtaining A3B5 materials with a low concentration of current carriers, which are in demand in the optoelectronic industry. Keywords: indium arsenide, rare earth element, Hall coefficient, concentration of current carriers, mobility of current carriers.