Group equations for moments of the relativistic electron distribution function in a cold gas of neutral atomic particles in an external electric field

A set of multigroup equations is derived for the first three moments of the distribution function for high-energy electrons in a gas of immobile atomic particles. The equations are intended for numerical simulation of processes in a dense weakly ionized plasma with the participation of high-energy electrons, including runaway electrons.     

Micellization and catalytic activity of the cetyltrimethylammonium bromide-Brij 97-water mixed micellar system

Surface tension measurements and the kinetic study of the basic hydrolysis of ethyl p-nitrophenyl chloromethyl phosphonate were used to examine the structural behavior and catalytic activity of the cethyltrimethylammonium bromide (CTAB)-polyoxyethylene (10) oleyl ether, C(18)H(35)(OCH(2)CH(2))(10)OH (Brij 97)-water mixed micellar system. Application of the regular solution model to the experimental data yields the value of the interaction parameter beta as -4.6, which indicates an attractive interaction of the surfactants in the mixed micelle and reflects synergistic solution behavior of the mixture. The mixed micellar composition is found to be enriched in the surfactant with the lower critical micelle concentration (cmc). In the kinetic study a nonmonotonic change in the pseudo-first-order rate constant of basic hydrolysis of the substrate is observed with increasing mole fraction of nonionic surfactant. The pseudophase micellar model reveals that the concentration factor mainly contributes to the catalytic effect, while the microenvironmental factor plays a negative role.     

Behavior of thermosensitive graft copolymer with aromatic polyester backbone and poly-2-ethyl-2-oxazoline side chains in aqueous solutions

Thermoresponsive graft copolymers with alkylene-aromatic polyester main chain and poly-2-ethyl-2-oxazoline side chains were synthesized. Two copolymer samples which differed in grafting density (0.5 and 0.7) were studied using dynamic and static light scattering and turbidimetry in aqueous solutions at concentration 0.0053?g?cm^?3. Hydrodynamic radii of scattering objects and their contribution to light scattering were obtained as a function of temperature in a wide temperature interval. Temperatures of phase separation were found out. Effect of grafting density on the copolymer behavior in aqueous solutions upon heating was determined. In particular, the phase separation temperature reduces with the decreasing grafting density.     

The influence of the structure of tetracoordinate phosphorus acid esters on the catalytic effect of the sodium dodecyl sulfate-hexanol-water ternary reverse micellar system

The catalytic effect of the sodium dodecyl sulfate-hexanol-water ternary reverse micellar system in the alkaline hydrolysis ofO-alkylO′-aryl chloromethylphosphonates as a function of the substrate structure was studied. The micellar effect is mainly determined by a change in the electronic properties of the substituents, while the hydrophobicity plays a secondary role. The kinetic data were examined in the framework of the pseudo-phase model of micellar catalysis. The rate constants of the reaction in the surface layer and the partition constants of the reactants were calculated. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1366–1370., August, 2000.     

Aggregation and catalytic properties of polymer-calix[4]resorcinarene-water-dimethylformamide systems

The aggregation in poly(ethylene imine) (poly(ethylene glycol))-calix[4]resorcinarene-water-dimethylformamide (30 vol %) systems and the catalytic activity of these compositions in hydrolysis of 4-nitrophenylbis(chloromethyl)phosphinate are studied by conductometry, tensiometry, lightscattering, and viscometry. Critical association concentrations, hydrodynamic radii of polymer-colloid aggregates, and kinetic parameters of hydrolysis are determined.     

Alkylation reaction of amines by dimethyl phosphite

The alkylation reaction kinetics of a series of amines of different structures by dimethyl phosphite have been studied. Two-parameter correlation equations have been deduced, relating reactivity to steric and inductive effects of substituent s attached to the nitrogen atom in the amine; a Swain-Scott equation has also been deduced, establishing a correlation between the rate of alkylation and the nucleophilicity of the reaction site. When steric conditions at the nitrogen atom are fixed, as in the case of orthoaminomethylphenols, the reactivity follows a Brönsted equation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1129–1133, May, 1990.     

Hole-electron mechanism of F-H pair generation in RbCl crystals with impurity electron traps

Production of F, Cl ₃ ⁻ , Ag⁰, and Tl⁰ centers in RbCl:Ag and RbCl:Tl crystals by photons having energies ranging from 5 to 10 eV has been studied at 295 and 180 K. It is shown that creation of near-impurity excitations is accompanied by formation of F centers localized in the vicinity of Ag⁺ and Tl⁺ ions. F centers are produced in direct optical generation of self-trapped excitons. In addition to the well-known mechanism of F-H pair production in nonradiative recombination of electrons with self-trapped holes, a hole-electron process has been revealed for the first time to operate in RbCl:Ag having deep electron traps. By this mechanism, F-H pairs appear in the following sequence of stages: thermally stimulated unfreezing of hopping diffusion of self-trapped holes (V _K centers), tunneling electron transfer from Ag⁰ to the approaching V _K centers, and subsequent nonradiative decay of triplet self-trapped excitons near Ag⁺ ions. Fiz. Tverd. Tela (St. Petersburg) 40, 1238–1245 (July 1998)