Papers by Author: Aleksandra A. Bozhko

Abstract: The instability of convection patterns representing a combination of vertical Rayleigh rolls and horizontal rolls resulting from longitudinal horizontal magnetic field is investigated in an inclined layer of magnetic colloid by experiments and numerical simulations. Visualization of convection patterns is provided by a temperature-sensitive liquid crystal film. The rich spectrum of convection structures is observed against different values of inclination angles and uniform magnetic fields. If the horizontal longitudinal magnetic field is strong enough it extinguishes the convection perturbations along the field direction and stabilizes Rayleigh flows. Observed patterns at about two supercriticalities and with small inclination angles show mostly spatially and temporally chaotic structures.

Abstract: The conductivity of metal-carbon-silicon nanocomposite films considered as potential candidates for the application as wide-range temperature sensors for severe environmental conditions is studied. The films combine unique properties of amorphous carbons with a new functionality imparted by the presence of metal nanoclusters in host matrix. The deposition of carbon-silicon phase was performed using PECVD of siloxane vapors. Metals (W, Nb, and Cr) with concentration in the range from 12 to 40 at. % were incorporated in the carbon-silicon host matrix by DC magnetron co-sputtering. The conductivity of the films decreases with temperature in the range 80-400 K, being well described by the power-law dependence. The conductivity mechanism found satisfactory explanation in the framework of the model of inelastic tunneling of electrons between metal nanoclusters dispersed in carbon-silicon matrix. The parallel study of the influence of metal concentration increase on carbon phase microstructure was carried out using Raman spectroscopy.