Influence of thermal load on the characteristics of a flow with evaporation

The two-layer flows of a liquid and a gas in a horizontal channel are investigated under condition of given gas flow rate. Evaporation on the thermocapillary interface is taken into account. An exact solution is constructed of the Navier–Stokes equations in the Boussinesq approximation, taking into account the Dufour effect in the gas-vapor layer. Within the framework of linear theory, the stability of the obtained solutions and the characteristics of the arising perturbations are studied. The influence is considered of the thickness of the liquid layer and the magnitude of the longitudinal temperature gradient on the structure of the basic flow and perturbations.     

Polymerization of trimethylene carbonate and lactones in the presence of magnesium monoionolate: A comparative theoretical and experimental study

Using quantum-chemical calculations (DFT, program Priroda), the formation of a catalyst species on the basis of magnesium complexes with 2,6-di-tert-butyl-4-methylphenol is discussed. A comparative theoretical and experimental study of the ring-opening polymerization of trimethylene carbonate, 1,4-dioxanone, δ-valerolactone, and ε-caprolactone in the presence of the monoionolate magnesium complex is performed. It is shown that the calculated values of activation barriers correlate with the observed order of activity of cyclic esters. The maximum rate of polymerization is exhibited by trimethylene carbonate.     

Synthesis of organic–inorganic sorbent containing phenylboronic acid as glucose-binding ligand

A copolymer with N-allylaminophenylboronic acid has been synthesized from a water-soluble N-vinylpyrrolidone–acrolein diethyl acetal copolymer. Immobilization of the obtained copolymer on silica gel afforded an organic–inorganic sorbent capable of sorbing glucose from model solutions.     

Synthesis and structure of catena((μ2-4,4,10,10-tetramethyl-1,3,7,9-tetraazaspiro[5.5]undecane-2,8-dione-O,O′)dichloro-zinc)

Russian Journal of Coordination Chemistry - The coordination polymer, catena-((μ2-4,4,10,10-tetramethyl-1,3,7,9-tetraazaspiro[5.5]undecane-2,8-dione-O,O′)dichloro-zinc)...     

Imbricin,an Antifungal Antibiotic of Non-Medical Application: Preparation,Physicochemical Properties,Structural Features,and Industrial and Agricultural Uses (Review)

Published data on the preparation, physicochemical properties, and structural features of imbricin, an antifungal antibiotic of non-medical application, were systematically described. Directions of practical application of imbricin in various areas of industry and agriculture were summarized.     

Mass Spectrometric Analysis of Microcystins from Cyanobacterial Biomass: Optimization of the Sample Preparation Procedure

The sample preparation procedure for determination of microcystins from biomass by the LC–MS method was optimized. Treatment of freeze-dried biomass samples with acetonitrile prior to the main extraction was effectively used for decreasing the amount of protein-like matrix compounds in extracts. Use of acetonitrile–water mixtures during the main ultrasound-assisted extraction allowed increasing the total microcystins amount in the resultant extracts compared to the traditional extraction using 75% methanol.     

Solubilization of prothionamide with micelles of an amphiphilic acrylic acid oligomer with thiohexyl terminal groups and preparation of postoperative cavity filling formulations

An amphiphilic oligomer was prepared by telomerization of acrylic acid in the presence of n-hexyl mercaptan. The structure, molecular weight, critical micelle concentration, and ζ-potential of the oligomer, and also its particle-size distribution in aqueous solution were determined. The product allows solubilization of prothiondamide antituberculosis drug. A procedure was suggested for preparing a filling formulation containing prothionamide for filling postoperative cavities in connective tissue.     

Structure and Thermal Stability of Nanostructured Precursor Powders of Copper(I) Sulfide and Selenide

The hydrochemical precipitation method at 298 and 333 K with, respectively, thiocarbamide and sodium selenosulfate was used to obtain nanostructured powders of copper sulfide with formula composition Cu₂S, which are composed of globules 200–500 nm in diameter, formed by 70–100-nm particles, and copper(I) selenide, composed of crystallites with polyhedral shape, sizes of 80 to 500 nm, and a formula composition Cu_1.84Se. An X-ray diffraction analysis revealed the orthorhombic Cu₂S structure (space group no. 39-Abm2) with unit cell parameters a = 1.182 nm, b = 2.705 nm, and c = 1.343 nm. Powders of Cu_1.84Se copper selenide have a cubic structure (space group Fm3m) with lattice constant a = 0.5693 nm. A thermal analysis demonstrated that the chemically precipitated Cu₂S and Cu_1.84Se powders have a stable elemental composition up to 200–240°C. An intense oxidation of the samples begins at a temperature exceeding 250°C and is accompanied by a sharp decrease in their content of sulfur (selenium) and by an increase in the content of oxygen.     

Low-Temperature Plasma-Chemical Deposition of Nanocomposite Antifriction Molybdenum Disulfide (Filler)–Silicon Oxide (Matrix) Coatings

It was demonstrated experimentally that the spatial separation of two processes of chemical vapor deposition, one of which provides synthesis of filler (MoS₂) nanoparticles and the other yields the matrix (SiO₂) of the nanocomposite coating, performed ina common reactor, enables an independent control over two process rates and makes it possible to widely vary the composition of the films deposited in this way. The deposition was performed in a double-zone vertical tubular quartz reactor. Molybdenum disulfide particles were produced by pyrolysis of aerosols of ammonium thiomolybdate solutions in dimethylformamide in the upper zone of the reactor, and the plasma-chemical deposition of a nanocomposite coating occurred in the lower zone into which MoS₂ nanoparticles were transported by the gas flow and tetraethoxysilane was delivered. It was shown that the nanocomposite coatings composed of molybdenum disulfide (filler) and silicon oxide (matrix) possess improve the antifriction properties as compared with the matrix (SiO₂ layers), these properties being determined by the relative amounts of MoS₂ nanoparticles in the layer and by their average size.     

Preparation of Ultramicroporous Materials by Fluidized-Bed Pyrolytic Deposition of Carbon in Pores of a Carbon Matrix

Samples of microporous materials were prepared by pyrolytic deposition of carbon from divinyl in a fluidized bed reactor onto carbon supports obtained from coconut and pine nut shells. The influence exerted on the adsorption capacity for CO2 by the divinyl pyrolysis temperature (in the range 600–750°С) and degree of densification (in the range 6–22%) was studied. Carbon deposition conditions ensuring the specific surface area (S_BET) lower than 5 m2 g^–1 at the adsorption capacity for СО₂ higher than 1 mmol g^–1 for both samples were found.