Characteristic features of reactions initiated by a flash corona discharge

The oxidation of solutes in water under the action of a flash corona discharge between solid electrodes and the water surface is investigated. The dependences of the oxidation rate on the gas-phase volume, the electrode-liquid distance, the discharge current, and the number of electrodes are examined. These dependences should be taken into consideration when designing reactors.     

Alteration of contact properties and chemical structure of polyethersulfone film surface by direct-current discharge treatment

Changes in the contact properties of the surface of polyethersulfone films modified at the cathode and the anode by dc discharge with varying the treatment time and discharge current have been studied. It has been shown that the treatment imparts hydrophilicity to the films, which persists for a long time. The chemical composition and structure of the surface of the modified films has been examined using X-ray photoelectron spectroscopy.     

Effects of cold plasma and UV-C radiation on isotonic solution

The possibility of hypochlorite formation by treating a 0.9% NaCl aqueous solution (isotonic solution) with pulsed UV-C radiation from a weakly ionized plasma of air spark discharge, continuous UV-C radiation from a low-pressure mercury lamp, or cold plasma of flash corona discharge has been explored in flow and batch modes. The mechanisms of reverse reactions in which the product hypochlorite is consumed have been analyzed. It has been shown that the reverse reaction is interrupted in the case of short-term contact of the processed liquid with flash discharge plasma; as a result, hypochlorite accumulates.     

Changes in the surface properties of plasma-modified polyfluoroolefin films during storage and heating

Changes in the wettability and surface contact properties of polytetrafluoroethylene (PTFE) and tetrafluoroethylene-ethylene copolymer films modified in a direct current discharge at the cathode and anode depending on the storage time in air at room temperature and on heating to 200°C have been studied. Changes in the chemical composition of film surfaces have been examined by X-ray photoelectron spectroscopy.     

Alteration in the surface properties of direct-current discharge-treated tetrafluoroethylene-ethylene copolymer films

A change in the contact properties of the surface of a tetrafluoroethylene-ethylene copolymer film by treatment of its samples mounted on the cathode and anode in a dc discharge has been studied. It has been shown that the modification leads to a significant improvement in the contact properties of the films owing to the appearance of oxygen-containing polar groups on the polymer surface. The formation of such groups has been proved by X-ray photoelectron spectroscopy. The peel strength of both the untreated and modified films was measured by the T-peel test method.     

The stability of rational approximations of analytic semigroups

It is shown thatA-acceptable and, more generally,A()-arational approximations of bounded analytic semigroups in Banach space are stable. The result applies, in particular, to the Crank-Nicolson method.     

Choice of conditions of an electrical discharge for generating chemically active particles for the decomposition of impurities in water

An electrical discharge between a liquid surface and an electrode positioned above it is considered. A second electrode, which delivers the output from a high-voltage source, is located at the bottom of the vessel containing the liquid. The conditions that must be met by the electrical discharge in order to efficiently initiate reactions in the liquid phase are analyzed. Under these conditions the number of active particles generated by the discharge turns out to depend on the concentration in the liquid of the substance with which the active particles interact. It is shown that for a corona or spark discharge the reactions can occur in a liquid layer 10–20 mm thick and that for specific reactions there exists an optimum value of the electric field at which the energy expenditures on the initiation of the reaction will be minimum. Zh. Tekh. Fiz. 69, 58–63 (January 1999)     

Synthesis of N-glycyl-β-glycopyranosylamines,derivatives of main human secreted oligosaccharide core structures

Russian Chemical Bulletin - β-Glycopyranosylamines were synthesized by the reaction of ammonium carbamate with di-, tetra-, and hexasaccharides, corresponding to the human milk and urine...