Liquid-phase chlorination ofC-chlorovinylsilanes

Liquid-phase chlorination of a number of chloro(chlorovinyl)methylsilanes was investigated. A number of novelC-chlorosilanes were characterized by IR and¹H NMR spectra. Some regularities of these reactions were determined; correlations between the structure of chloro(chlorovinyl)methylsilanes and their reactivities were identified.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2256–2260, November, 1995.     

Epoxy Composites Modified with Finely Dispersed Fillers

The thermal stability and mechanical strength of composites based on ED-20 epoxy oligomer cured with isomethyltetrahydrophthalic and methylendic anhydrides was studied as influenced by the nature and properties of finely dispersed inorganic fillers, such as carbon black, aluminum oxide, and silica nanoparticles.     

Dual-jet plasmatron for medical applications

We present a design for a dual-jet arc plasmatron operating at a frequency of 66 kHz in an argon flow at atmospheric pressure. We present the results of determination of the temperature, electron concentration, and electrode erosion obtained by atomic emission spectral analysis. The proposed convenient design for a dualjet plasmatron and the low erosion of the copper electrodes in the plasma make it possible to use it for medical purposes. Report given at the Fifth International Conference on Plasma Physics and Plasma Technologies (PPPT-5), 18–22 September 2006, Minsk, Belarus. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 1, pp. 139–140, January–February, 2007.     

Algorithm for the numerical proof of the existence of periodic trajectories in two-dimensional nonautonomous systems of ordinary differential equations

We suggest an algorithm that permits one to prove the existence of limit periodic trajectories (cycles) in two-dimensional nonautonomous dissipative systems with periodic coefficients with the use of computational methods alone. We prove a fixed point theorem for two-dimensional mappings and describe methods of its application to two-dimensional nonautonomous systems with the use of the Poincaré mapping and interval arithmetics.     

Applicability of the Interval Taylor Model to the Computational Proof of Existence of Periodic Trajectories in Systems of Ordinary Differential Equations

We consider the construction of the interval Taylor model used to prove the existence of periodic trajectories in systems of ordinary differential equations. Our model differs from the ones available in the literature in the method for describing the algorithms for the computation of arithmetic operations over Taylor models. In the framework of the current model, this permits reducing the computational expenditures for obtaining interval estimates on computers. We prove an assertion that permits establishing the existence of a periodic solution of a system of ordinary differential equations by verifying the convergence of the Picard iterations in the sense of embedding of the proposed Taylor models. An example illustrating how the resulting assertion can be used to prove the existence of a closed trajectory in the van der Pol system is given.     

Alkoxylation ofC-chlorovinylsilanes

The alkoxylation and isopropylideneiminoxylation ofC-chlorovinylmethylchlorosilanes with various alcohols and acetone oxime were investigated. A series of newC-chlorovinylmethylalkoxy- and -isopropylideneiminoxysilanes was characterized by IR and¹H NMR spectra. The effect of the number of chlorine atoms inC-chlorovinylmethylchlorosilanes on their reactivity in these reactions was determined.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 737–742, April, 1995.     

Thermodynamic properties of the first to fifth generations of carbosilane dendrimers with allyl terminal groups

Temperature dependences of the specific heats, characteristic temperatures, and enthalpies of physical transformations of the first to fifth generations of carbosilane dendrimers with allyl terminal groups were studied using an adiabatic vacuum calorimeter in the temperature range 6—340 K. The error of measurements was, as a rule, about 0.2%. Thermodynamic characteristics of physical transformations of the dendrimers were determined and their thermodynamic functions C _p°(T), H°(T)—H°(0), S°(T)—S°(0), and G°(T)—H°(0) were calculated for the temperature range 0—340 K. The thermodynamic functions of the dendrimers are linearly related to their molecular weights, the number of allyl groups on their outer spheres, and the number of moles of diallylmethylsilane per mole of the dendrimers formed. Additive dependence of the properties of the dendrimers on their chemical composition and structure indicates that the energy of interaction between structural fragments of the dendrimers is independent of the dendrimer generation number. The fractal dimensions, D, of all dendrimers studied in this work are 1.2—1.3 in the temperature range 30—50 K, thus indicating a chain-layered structure of the dendrimer glasses.     

Hydrothermal synthesis of nanodispersed α-Fe2O3 with a lamellar shape of crystals

Transformations of oxyhydroxides of iron(III), which are formed in the process of oxidation of iron(II) in Fe(OH)₂ suspensions upon the hydrothermal treatment at 150–220°C in water and in aqueous solutions of potassium hydroxide with concentrations of 1–5 mol/L have been studied. The dependences of the phase composition and dispersity of the arising products and the morphology of α-Fe₂O₃ on the parameters of heat treatment and on the phase composition of FeOOH have been determined. Conditions for obtaining nanodisperse α-Fe₂O₃ with a lamellar shape of crystals have been refined.     

Study of the passage from a dissipative to a conservative state in two-dimensional nonlinear systems of ordinary differential equations

We consider an approximate model of a space pendulum described by a system of two equations. We construct a two-dimensional diagram in the parameter space showing the passage from a dissipative to a conservative state in this system. We show that the Poincaré map of this system can be represented as the square of some other map; this fact is used to explain some specific features of the structure of the bifurcation diagram of the original map.     

Investigation of saddle-node and pitchfork bifurcations by Magnitskii’s stabilization method

We consider Magnitskii’s method in almost original form and prove a property of it, on the basis of which we suggest a way to use the method for stabilizing saddle cycles and cycles passing through a pitchfork bifurcation. By way of example, we consider some solutions of the four-dimensional Yang-Mills equations in the presence of the Higgs mechanism.