Modeling and investigating of the influence of surface roughness on the strength of electrically conductive fiber

In the framework of the model of locally inhomogeneous electrically conductive nonferromagnetic solid, the near-surface inhomogeneity in a solid cylinder is investigated. It is shown that such inhomogeneity is characterized by three characteristic sizes associated with the structural inhomogeneity of the material, the roughness of the real surface and the electronic subsystem. The charge distribution features a double electric layer. The size effect of fiber strength and its dependence on geometric inhomogeneity parameters of the surface are studied.

A Study of Influence of Surface Nanosized Gaseous Structures on the Water Freezing Rate and Wettability of Metallic and Oxide Substrates

In a series of experiments using thermal gradient “cool water-warm substrate”, an increase of number and sizes of surface gaseous nanostructures during an increase of the temperature difference was found to give rise to a decrease of surface hydrophobicity. It was established that the higher the surface inhomogeneity, the shorter the time of water freezing. In case of HOPG, an extremely long lifetime of overcooled to -20 °С water of ~100 min was observed when surface gas nanostructures persisted. This can be understood in terms of a “gas screening” of surface inhomogeneity which could potentially act as ice nucleation centers

Oxygen Sensors Based on Thin Films of Gallium Oxide Modified with Silicon

The results of an investigation of the electrical resistivity of Ga2O3 thin films modified with silicon under the influence of oxygen in the range of O2 from 9 to 100 vol. % and changes in the heating temperature of structures from 25 to 700 °C were presented. Thin films of Ga2O3 were obtained by RF magnetron sputtering of Ga2O3 targeted with pieces of Si on the target’s surface in oxygen–argon plasma. The possibility of developing selective oxygen sensors based on thin films Ga2O3 modified with silicon with a temperature of maximum response 400 °C was shown. Oxygen influence leads to a reversible increase in the samples’ resistance, due to the chemisorption of oxygen on the surface of thin Ga2O3 films. An increase in the response of sensors based on the thin polycrystalline films of gallium oxide modified with silicon is caused an increase in the adsorption centers for O−, due to an increase in the surface inhomogeneity and the appearance of additional adsorption centers Si4+.

The computer System for coulostatic experiments. The adsorption measurements unit

Mathematical model and corresponding computer application for determination of adsorption characteristics in coulostatic experiments on solid electrodes were developed. The model simulates coulostatic relaxation of the electrodes' potential while adsorption is considered as slow stage. Impact of the surface inhomogeneity on potential curves behavior is discussed.Kinetic and adsorption parameters of the electrode reactions under investigation were determined with use of an automated measuring system.Model's adequacy was checked by comparison of real experimental data with output of computer simulation. Routines described above were developed as procedures of specialized unit within computer system for coulostatic measurements. Use of uniform data during the whole cycle of experiment series makes the simulation process more convenient for researcher and more effective with regard to time of calculation as well as reliability of results.