Origin of grey spots on the surface of metallic glasses under Ar ion irradiation: The surface and volume properties

The nature of grey spots on the surface of amorphous Fe₆₇Cr₁₈B₁₅ metglass ribbons irradiated by 30 keV Ar⁺ ions is investigated. Changes in the surface and volume properties of samples are analyzed bearing in mind the presence of competitive processes of ordering and disordering in the structure under irradiation at initial stage of crystallization (T = 500 °C). Changes in the volume properties of the samples become apparent in their structure, electrical and magnetic properties and are caused by radiation-enhanced diffusion at high gradients in the concentration of defects generated by Ar⁺ irradiation. It is established that grey spots are shown by decrease in the reflection coefficient in a visible range. They emerge as a result of reorganization in the electronic structure of irradiated ribbons due to damage in the short-range order and formation of non-uniformly scaled atomic structure during transition from the medium-range to the long-range atomic order. Experimental data are in accord with the calculations in the framework of the free electrons model.     

Naum Il'ich Akhiezer (on the 100th Anniversary of His Birth)

Ukrainian Mathematical Journal -     

Effect of Ion (Ar+) Irradiation on Cluster Magnetism and Magnetic Interactions in Fe67Cr18B15 Amorphous Alloy

Physics of the Solid State - The comparison of the resonance magnetic absorption spectra with the data on structure and magnetic properties of Fe67Cr18B15 amorphous samples has shown that a...     

Theory of Multidimensional Delsarte–Lions Transmutation Operators. II

Ukrainian Mathematical Journal - The differential-geometric and topological structures related to the Delsarte transmutation operators and the Gelfand–Levitan–Marchenko equations that...     

Thermal modes of a plug flow reactor with a liquid–liquid heterogeneous system

The thermal modes of a flow plug reactor with an exothermic chemical reaction are numerically simulated. A heterogeneous reaction system consisting of two immiscible liquids is studied: one of the liquids (dispersed phase) in the form of droplets is distributed in the other (dispersion phase). The characteristics of the thermal modes of the reactor at various values of two governing parameters, the Damköhler number and the rate of extraction of the dissolved substance from the dispersed phase into the dispersion phase is examined. Two modes of chemical reaction in the reactor are demonstrated to be possible: low-temperature and high-temperature. Critical criteria of thermal ignition are formulated. The dependence of the structure of the thermal wave on the governing parameters is investigated.     

Neumann Boundary-Value Problem for a Singularly Perturbed Heat Equation with Pulse Action

We propose an algorithm for the construction of an asymptotic solution of the Neumann boundary-value problem for a singularly perturbed heat equation with pulse action at fixed times. A theorem on the order with which the asymptotic solution satisfies the original problem is proved.__________Translated from Neliniini Kolyvannya, Vol. 8, No. 1, pp. 89–122, January–March, 2005.     

Macrokinetics of initial stages of liquid-phase oxidation of hydrocarbons by nitric acid

The influence of mass transfer on the rates of initial stages of liquid-phase oxidation of hydrocarbons by nitric acid was analyzed. The parameters of the diffusion-controlled nearsurface regime were determined.