Copolymer from the waste products of styrene and maleic acid production

Influence of the process conditions on the production of “STAM” copolymer from waste products formed at join producing of styrene and propylene oxide, the acetophenone bottom residue at styrene rectification, with maleic acid. Effects of temperature, copolymerization process duration, weight ratio of acetophenone bottom residue to maleic acid and styrene content in the bottom residue are studied.     

4-hydroxy-2-quinolenes. 24. Improved synthesis and biological properties of hydrochlorides ofβ-dialkylaminoalkylamides of 1-alkyl-2-oxo-4-hydroxyquinoline-3-carboxylic acids

High-purity hydrochlorides of-dialkylaminoalkylamides of 1-R-2-oxo-4-hydroxyquinoline-3-carboxylic acids have been obtained from N-alkyl-2-carbalkoxyanilides of malonic acid. The synthesized compounds have been tested for certain forms of pharmacological activity.For Communication 23, see [1].Ukrainian Pharmaceutical Academy, Khar'kov 310002. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1400–1405, October, 1994. Original article submitted November 8, 1994.     

4-Hydroxy-2-quinolones. 26. Bromination of 3-substituted 2-oxo-4-hydroxyquinolones

The bromination of 3-alkyl- and 3-ethoxycarbonyl-2-oxo-4-hydroxyquinolones by molecular bromine gave 3-bromo-3-R-2,4-dioxoquinolones. Under analogues conditions, 1-R-2,4-dioxo-3H-quinolone-3-carboxylic acids form 1-R-3-bromo-2-oxo-4-hydroxyquinolones. The results of the study of the antimicrobial activity of the compounds synthesized are presented.For Communication 25, cf. [1].Ukrainian Pharmaceutical Academy, Khar'kov, 310002. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 204–207, February, 1995. Original article submitted November 8, 1994.     

Analysis of the oscillation intensity of RHEED specular reflection during the MBE growth of CaF<Subscript>2</Subscript>/Si/CaF<Subscript>2</Subscript> structures

The results of analysis of the oscillation intensity of RHEED specular reflection during the MBE growth of CaF₂/Si(111) structures in a wide temperature range from 100 to 600°С are presented. It is shown that the preliminary formation of a 2D Si buffer layer provides the two-dimensional growth of CaF₂ layers. Possible reasons which for the disruption of 2D growth at high substrate temperatures are discussed.     

On asymptotic properties of solutions defined on a half-axis to one semilinear ordinary differential equation

We consider solutions to the semilinear ordinary differential equation with a nonlinear term of Emden–Fowler type. The results about the asymptotic behavior of the solutions to the Emden–Fowler equation defined in a neighborhood of infinity, presented in the book of R. Bellman, are extended to the case of equation with lower-order derivative.     

Polymerization of hexaethylcyclotrisiloxane during the synthesis of carbofunctional oligo(diethylsiloxane diols)

Oligo(diethylsiloxane diols) carrying β-oxyethoxymethyl terminal groups are synthesized for the first time by the cationic polymerization of hexaethylcyclotrisiloxane in the presence of bis(β-oxyethoxymethyl)tetramethyldisiloxane with the use of sulfuric acid or the cationite KU-23 as a catalyst. It is shown that, along with oligo(diethylsiloxane diols), the products of rearrangement of diethylsiloxane chains, such as octaethylcyclotetrasiloxane and higher cycles, are formed. The reaction of dipotassium salts of oligo(diethylsiloxane diols) with chlorosilanes of the formula ClSi(CH₃)₂CH₂O(CH₂)₂OCOCH₃ yields acetoxy-terminated oligomers that contain octaethylcyclotetrasiloxane and higher cycles as well.     

Current Status and Objectives of Modernizing the Engineering,Physical, and Energy Infrastructure of the SFT Facility for the Implementation of the Ignitor Project

Physics of Atomic Nuclei - The Ignitor tokamak nuclear fusion research project is one of the most ambitious initiatives undertaken under the long-term scientific cooperation program between the...     

Estimation of performance parameters of a frontal variant of optoacoustic determination with a model system

Using a model system, the applicability of the frontal configuration of optoacoustic spectroscopy in analytical practice is shown. An optoacoustic cell made using layered-prism geometry was designed and tested; it ensures operation with a layer thickness of 20–100 μm and sample volumes of 50–100 μl. Conditions are proposed for determining iron(II) in the form of tris(1,10-phenanthrolinate) with the detection limit of 3 × 10⁻⁷ M, which is less that the detection limit under similar induction conditions and for the same determination procedure using thermal-lens spectrometry (4 × 10⁻⁷ M). The determination has high reproducibility (relative standard deviation for 10⁻⁶ M is 0.005) and expressivity (1 min per sample detection).     

Homogenization of Semilinear Parabolic Operators in a Perforated Cylinder

In this paper, we consider a semilinear parabolic equation of second order with lower term a power function of the unknown function and prove that the sequence of solutions in a perforated cylinder tends to a solution in a unperforated cylinder if the radii of rejected balls in the parabolic metric tend to zero at the rate depending on the exponent of the power function in the lower term.