Low-power RF plasma sources for technological applications: II. plasma sources under anomalous skin effect conditions

A theory of a planar disk-shaped RF plasma source under anomalous skin effect conditions is developed. In the absence of an external magnetic field, such conditions are satisfied for transverse electromagnetic waves with phase velocities below the electron thermal velocity, and, in the presence of this field, they are satisfied for electron cyclotron waves with frequencies corresponding to the resonant absorption line. For each of these cases, the RF field power deposited in a plasma with given parameters is determined and the equivalent plasma resistance is calculated.     

Minimax solutions of Hamilton–Jacobi functional equations for neutral-type systems

A functional Hamilton–Jacobi equation with covariant derivatives which corresponds to neutral-type dynamical systems is obtained. The definition of a minimax solution of this equation is given. Conditions under which such a solution exists and is unique and well defined are found.     

Potassium-conducting solid electrolytes in the systems K2 ? 2xAl2 ? xMxO4 (M = Nb, Ta)

New potassium-monoaluminate-based solid electrolytes with high potassium-cationic conductance are synthesized, by partial substitution of penta-charged cations Nb⁵⁺ and Ta⁵⁺ for Al³⁺ cations, and studied. Both additives increased drastically the KAlO₂ conductivity over the entire studied temperature range. The reason for the increase in the potassium monoaluminate conductivity, on the introducing of the studied additives, is the formation of potassium vacancies as a result of the substitution reaction Al³⁺ → Nb⁵⁺(Ta⁵⁺) + 2V’c, as well as broadening of the region of existence of the KAlO₂ high-temperature γ-modification whose transport properties exceed those of the low-temperature β-form.     

Formation of Nonmetallic Inclusions of Variable Composition During Unidirectional Solidification of Liquid Steel

A two–dimensional unsteady mathematical model is presented for numerical study of the formation of nitrogen–containing compounds of variable composition during unidirectional solidification of liquid steel. The model allows calculation of the distributions of temperature and concentrations of soluble admixtures, the shape of solidification boundaries, the coordinate of the beginning of the chemical reaction, and the composition and mass of inclusions formed in the uncrystallized zone of the ingot and in the two–phase region.     

Mössbauer Study of Thin Iron Film Beryllization

Beryllium coating of the iron foil is made by means of magnetron sputtering. Mössbauer studies are performed by means of two registration techniques: conversion electron Mössbauer spectroscopy (CEMS) and the γ-ray technique in absorption geometry. Performed investigations confirm the original thermodynamic approach to creation of thermally stable multi-layer materials.

     

Synthesis of dense ceramics of single-phase mayenite (Ca<Subscript>12</Subscript>Al<Subscript>14</Subscript>O<Subscript>32</Subscript>)O

The nanoporous material mayenite was synthesized by two methods: solid-phase and self-propagating high-temperature (combusting) (SHS) syntheses. The structure of the materials was determined by the X-ray diffraction analysis and IR and Raman spectroscopy.     

Preparation, structure, and properties of metal nanocomposites in lithium niobate

Crystals of lithium niobate LiNbO₃ are implanted with 60-keV Cu^? ions at different ion fluxes to a fluence of 2 × 10¹⁷ ions/cm². The structure and the linear and nonlinear optical properties of the implanted layers are investigated. The optical transmission and ion-induced photon spectra of the LiNbO₃ crystals are measured in the course of implantation. It is revealed that the implantation brings about the formation of complex nanocomposites consisting of metallic copper nanoparticles and nanodomains of the matrix. The distributions of nanoparticles and nanodomains in the implanted layers do not correlate with each other. It is shown that the variations in the linear and nonlinear optical absorption of the nanocomposites are predominantly determined by the changes in the chemical composition and the structure of the matrix.     

Inequalities for Subgradients of a Value Functional in Differential Games for Time-Delay Systems

Doklady Mathematics - A two-person zero-sum positional differential game is considered in which the motion of a dynamical system is described by a nonlinear delay equation and the initial motion...     

Oxygen isotope exchange in the LSM-YSZ composite under the conditions of long-term tests

The stability of the properties of the composite 40 vol % La_0.6Sr_0.4MnO_{3 ? δ}-60 vol % Zr_0.83Y_0.17O_1.92 (LSM-YSZ) held for 1000 h at a temperature of 800°C and an oxygen pressure of 1.01 kPa and changes in its microstructure were studied by isotope exchange and gas-phase analysis. The oxygen exchange was found to occur by the dissociative adsorption mechanism involving the adsorption forms of oxygen on the triple-phase LSM-YSZ-O₂ boundary. The rate-determining step of the oxygen exchange of the composite did not change with time. The rate of oxygen exchange decreased by 22%, which is comparable to the decrease in the length of the LSM-YSZ-O₂ triple-phase boundary (～20%), on which oxygen exchange is dominant. The conductivity of the LSM-YSZ composite increased due to the connectivity of the material.