Ionization Processes in a Carbon Aerosol Upon Exposure to Long Laser Pulses. I

Russian Physics Journal - The interaction mechanisms of low-energy long-duration (~1 ms) laser pulses with dispersed particles in air are considered. The basic equations describing the mechanisms...     

An effect of surfactants of different nature on stabilization of foaming systems containing polyvinyl alcohol

The laws of the foam stabilization by mixtures of surfactant of different nature: sodium dodecyl sulfate C₁₂H₂₅OSO₃Na and cetyltrimethylammonium bromide C₁₆H₃₃N(CH₃)₃Br with a nonionic polymer, polyvinyl alcohol were established. High stability of foams from mixtures of surfactant-polyvinyl alcohol compared with the individual components can be related to the formation of mixed structured layers of surface active associates of polyvinyl alcohol with surfactant contributing to thickening of foam films.     

Crystal and molecular structure of tigogenin

Tigogenin [(25R)-5α-spirostan-3β-o1] was isolated from Digitalis lanata Ehrh., and its crystal and molecular structure was determined by single crystal X-ray diffraction.     

Quality of Speech Reproduction Using Stochastic Digital Systems of Information Transfer with its Statistical Compaction

Russian Physics Journal - Quality of oral speech reproduction using stochastic digital systems of information transfer at its statistical compaction is analyzed (on the example of Russian and...     

Polymer-metal complexes in polyelectrolyte multilayer films as catalysts for oxidation of toluene

We report on the binding of metal ions (Me(2+); Co(2+) and Cu(2+)) with weak polyelectrolyte multilayers (PEMs), as well as on catalytic activity of PEM-Me(2+) films for oxidation of toluene. Using several types of PEM films constructed using branched polyethyleneimine (BPEI) or quaterinized poly-4-vinylpyridines (QPVPs) as polycations and poly(acrylic acid) (PAA) or poly(styrene sulfonate) (PSS) as polyanions, we found that binding of Co(2+) and Cu(2+) ions with a PEM matrix can occur both through coordination to polycationic amino groups and/or ionic binding to polyacid groups. The amount of metal ions loaded within the film increased linearly with film thickness and was strongly dependent on polyelectrolyte type, film assembly pH, and fraction of permanent charge in polymer chains. Among various PEM-Me(2+) systems, BPEI/PAA-Co(2+) films assembled at pH 8.5 show the best catalytic performance, probably because of the preservation of high mobility of Co(2+) ions coordinated to amino groups of BPEI in these films. With BPEI/PAA-Co(2+) films, we demonstrated that films were highly permeable to reagents and reaction products within hundreds of nanometers of the film bulk; i.e., film catalytic activity increased linearly with layer number up to 30 bilayers and slowed for thicker films.     

Extinction Coefficient of Optical Fibers Irradiated by Thermal Neutrons and Compressed

Russian Physics Journal - Results of experimental studies of the extinction coefficient of optical fibers preliminary irradiated by thermal neutrons and compressed are presented. In this case,...