Highly Luminescent Solution-Grown Thiophene-Phenylene Co-Oligomer Single Crystals

Thiophene-phenylene co-oligomers (TPCOs) are among the most promising materials for organic light emitting devices. Here we report on record high among TPCO single crystals photoluminescence quantum yield reaching 60%. The solution-grown crystals are stronger luminescent than the vapor-grown ones, in contrast to a common believe that the vapor-processed organic electronic materials show the highest performance. We also demonstrate that the solution grown TPCO single crystals perform in organic field effect transistors as good as the vapor-grown ones. Altogether, the solution-grown TPCO crystals are demonstrated to hold great potential for organic electronics.</p

Concentration effects in the base-catalyzed hydrolysis of oligo(ethylene glycol)- and amine-containing methacrylic monomers

Concentration effects in the base-catalyzed hydrolysis of water-soluble methacrylates (3-(N,N-dimethylaminoethyl) methacrylate (DMAEMA), 2-hydroxyethyl methacrylate (HEMA) and oligo(ethylene glycol) methacrylates (OEGMAs)) have been studied. These monomers are rapidly hydrolyzed in the presence of bases at the room temperature in dilute aqueous solutions, but the reaction rate decreases sharply in highly concentrated solutions. A clear correlation was found between a form of the viscosity isotherm for DMAEMA solutions and the concentration dependence of the autocatalytic hydrolysis rate which indicates the connection of process kinetics with the structure of solutions. These data should be considered when carrying out homo- and copolymerization of the previously mentioned monomers in aqueous solutions

Effect of ultrasonic treatment and polymer additive on structural-mechanical properties of solutions of paraffinic hydrocarbons

The effect of a polymer additive based on an alkyl acrylate-dodecylamine acrylate copolymer, ultrasonic treatment, and their combined treatment on structural and mechanical properties of oil paraffin solutions in kerosene are investigated. It is found out that after a combined treatment of 6 wt. % solution of petroleum paraffin in kerosene, the maximum decrease in viscosity, pour point, and amount of deposits is observed

Effect of ultrasonic treatment and polymer additive on structural-mechanical properties of solutions of paraffinic hydrocarbons

The effect of a polymer additive based on an alkyl acrylate-dodecylamine acrylate copolymer, ultrasonic treatment, and their combined treatment on structural and mechanical properties of oil paraffin solutions in kerosene are investigated. It is found out that after a combined treatment of 6 wt. % solution of petroleum paraffin in kerosene, the maximum decrease in viscosity, pour point, and amount of deposits is observed

Graphene Nanoflake- and Carbon Nanotube-Supported Iron&ndash;Potassium 3D-Catalysts for Hydrocarbon Synthesis from Syngas

Transformation of carbon oxides into valuable feedstocks is an important challenge nowadays. Carbon oxide hydrogenation to hydrocarbons over iron-based catalysts is one of the possible ways for this transformation to occur. Carbon supports effectively increase the dispersion of such catalysts but possess a very low bulk density, and their powders can be toxic. In this study, spark plasma sintering was used to synthesize new bulk and dense potassium promoted iron-based catalysts, supported on N-doped carbon nanomaterials, for hydrocarbon synthesis from syngas. The sintered catalysts showed high activity of up to 223 &mu;molCO/gFe/s at 300&ndash;340 &deg;C and a selectivity to C5+ fraction of ~70% with a high portion of olefins. The promising catalyst performance was ascribed to the high dispersity of iron carbide particles, potassium promotion of iron carbide formation and stabilization of the active sites with nitrogen-based functionalities. As a result, a bulk N-doped carbon-supported iron catalyst with 3D structure was prepared, for the first time, by a fast method, and demonstrated high activity and selectivity in hydrocarbon synthesis. The proposed technique can be used to produce well-shaped carbon-supported catalysts for syngas conversion

Эффективная диэлектрическая проницаемость среды с периодическими включениями

A method for estimating the effective dielectric permittivity tensor is described in the paper. The method is based on variational principle for media with periodic inclusions. It allows one to obtain upper and lower bounds for possible values of the dielectric permittivity of a two-component system. Numerical results for composite structures with dielectric (metal) cubical and spherical inclusions are presentedВ статье описывается метод оценки тензора эффективной диэлектрической проницаемости, основанный на вариационных принципах для сред с периодическими включениями, который позволяет получить двусторонние границы области возможных значений диэлектрической проницаемости двухкомпонентной системы. В качестве примеров показаны расчёты для композитных структур с кубическими и шаровыми включениями из диэлектрика и металл