In this study, plasma discharge in liquids in the intense ultrasonic field above the cavitation threshold has been proven to be of great interest for initiation of various physical and chemical processes. The feature of arc discharge in liquid media is the localization of plasma region near the electrodes and the "falling" form of volt-ampere characteristics. In the region of intense cavitation, the fraction of gas-vapor component in the liquid exists, therefore it can be assumed that the electric breakdown in the cavitation region should become easier, which can result in initiation of various forms of discharges.

Physical methods for obtaining nanosized materials and structures in liquid-phase media, characterized by the action of high energies on a substance, are considered: the synthesis of nanomaterials in plasma and under the action of intense ultrasonic vibrations above the cavitation threshold. It is shown that liquid-phase plasma-chemical reactions are in a certain sense similar to sonochemical reactions, since both of these types of processes represent a local concentration of high energies in liquid reaction media. The data of the experimental and theoretical works of domestic and foreign researchers on the plasma-chemical and sonochemical synthesis of nanomaterials of various compositions and structures are analyzed, and it is shown that the application of high-energy sources to chemical processes can significantly change their course and make it possible to synthesize nanosized materials that cannot be obtained under other conditions or has a low speed and a low yield of the final product. The prospectives of continuing such work in the future for the development of methods for the synthesis and study of the properties of nanomaterials are shown. It is shown that the combined effect of high-intensity ultrasonic oscillations above the cavitation threshold and pulsed or stationary electric fields on a liquid medium leads to the appearance of a special form of electric discharge in a cavitating liquid medium, which is still an understudied physical phenomenon with original electrophysical and optical characteristics, and the study as a method of targeted synthesis of nanosized materials is a new scientific challenge.

The paper proposes a numerical-analytical method for solving the inverse problem of identification of the components of the thermal conductivity tensor in anisotropic materials on the basis of the earlier analytical solution of the heat conduction problem in anisotropic half-space when heated with a thermal flow. The method is based upon expansion of the residual functional into Taylor series and determination of incremental vectors of the target coefficients which are then used for application of iterative gradient descent algorithms. The solution demonstrates fine iteration convergence even if the initial approximation of the coefficients vector differs from the target one by several times, and even when there is some inaccuracy in the experimental data. The proposed method can be used for a wide range of problems in continuum mechanics.

In this study, plasma discharge in a liquid at intensive ultrasonic field above the cavitation threshold has been proven to be of great interest for initiation of various physical and chemical processes. In such discharge, nanoparticles of tungsten and zinc oxides have been synthesized. Further exploration of synthesized nanoparticles has demonstrated that the factor of ultrasonic cavitation during the synthesis substantially affects physical and chemical characteristics of nanoparticles.

The effect of high-energy mechanical processing on the adsorption behavior of the hydrophilic polymer ethyl hydroxyethyl cellulose (EHEC) on the surface of the inorganic pigments TiO₂ and Fe₂O₃ has been studied by IR spectroscopy. High-energy processing of aqueous disperse systems of TiO₂ and Fe₂O₃ activates the surface of the inorganic oxides and promotes polymer adsorption. We present the first evidence that the interaction of EHEC with oxide surfaces is accompanied by conformational changes in the adsorbed EHEC molecules. The conformational transitions depend on the lattice parameters of the inorganic oxides and lead to the formation of special adsorbed solvated EHEC layers, which determine the sedimentation stability of the disperse system.

A method is developed for applying metallic, intermetallic, or ceramic coatings to a metal surface by means of ultrasound (high-frequency acoustic vibrations). The method may also be used to...