Use of spectral methods to study branching processes with diffusion in a noncompact phase space

Moscow State University. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 88, No. 1, pp. 25–30, July, 1991.     

One-pot synthesis of 1,5,3-oxathiazepanes via the three-component condensation of primary amines,formaldehyde and 2-mercaptoethanol

The three-component condensation reaction of primary amines, formaldehyde and 2-mercaptoethanol using salts of transition and rare earth metals as catalysts was developed to obtain a new 7-membered heterocyclic structural building block, 1,5,3-oxathiazepanes, in good to excellent yields. The structure of the heterocyclic fragment was confirmed by NMR spectroscopy.     

Thermal behavior of Ni,Cu- and Ce,Zr-containing oxide layers on titanium,formed by plasma-electrolytic oxidation technique

The influence of air annealing at 800, 850, and 900°C on the composition and structure of the surface of Ni,Cu- and Ce,Zr-containing oxide structures on titanium, formed by the plasma-electrolytic oxidation technique, was examined.     

Stability and Instability of Steady States for a Branching Random Walk

Methodology and Computing in Applied Probability - We consider the time evolution of a lattice branching random walk with local perturbations. Under certain conditions, we prove the Carleman type...     

Vibrations of Circular Sandwich Plates under Resonance Loads

The paper studies axisymmetric resonance vibrations of an elastic circular sandwich plate under local periodic surface loads of rectangular, sinusoidal, and parabolic forms. The hypotheses of broken normal are used to describe the kinematics of the plate, which is asymmetric in thickness. The core is assumed to be light. The initial–boundary-value problems are solved analytically. The solutions are analyzed     

Multilayered coatings that are stable at low temperatures

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 52, No. 4, pp. 649–654, April, 1990.     

Phase separation in semi-interpenetrating polymer networks based on crosslinked poly(urethane) and linear poly(methyl methacrylate) containing iron,copper, and chromium chelates

Phase separation that occurs during formation of semi-interpenetrating polymer networks of various compositions based on crosslinked poly(urethane) and linear poly(methyl methacrylate) containing 1 wt % iron, copper, and chromium chelates has been studied by the methods of DSC and DMA. It has been shown that, in contrast to chromium chelates, the incorporation of iron and copper β-diketonates into the semi-interpenetrating polymer networks (PU : PMMA = 50 : 50) causes retardation of phase separation owing to high rates of poly(urethane) and poly(methyl methacrylate) formation and the appearance of chelate complexes with both blend components at the interface. A more complete phase separation in metal-containing semi-interpenetrating polymer networks (PU : PMMA = 70 : 30) is associated with the fact that chemical kinetics and complexation processes act in opposite directions. The latter processes prevail, and the influence of the type of metal ion in a chelate that predominantly interacts with PU in the blend is diminished.     

Combination of plasma-electrolytic oxidation and extraction-pyrolytic method for formation of metal oxide layers

Elemental composition and morphology of oxide coatings formed on stainless steel, nickel alloy (nonvalve metals), and titanium (valve metal) by plasma-electrolytic method combined with the extraction-pyrolytic technique are reported. It is shown that combination of these methods is promising for obtaining oxide coatings with a complex chemical composition and various physicochemical properties.