Effect of Technological Parameters of Interaction between SiF4 and CaH2 on the Nature of Filtration Combustion

Interaction of silicon tetrafluoride and calcium hydride in a metallic vertical flow-through reactor in the filtration combustion mode was studied. It was shown that the stationary course of the process requires that the reactor should be heated to 100°C, and the ignition furnace, to 150°C. If the reactor is heated to more than 110°C, and the ignition furnace, to more than 170°C, the stationary mode of the process is disrupted and the reaction front is doubled. If a porous phase of varied dispersity is charged, a standing combustion wave is formed.

     

Enhanced Raman scattering provided by fullerene nanoclusters

Two new nonlinear optic effects are observed in crystalline solutions of fullerenes in toluene and carbon tetrachloride. Both are provided by a self-clustering of the solute molecules and are referred to fullerene-enhanced Raman scattering and solvent-enhanced luminescence. The effects are induced by the excitation of charge-transfer states of the fullerene nanoclusters, which makes the latter act as amplifiers of local electric fields. The text was submitted by the authors in English.     

Explosive characteristics of tetrafluoroethylene

The minimum energies required to initiate the combustion of gaseous tetrafluoroerthy1ene (TFE) and mixtures thereof with nitrogen, argon, and helium at various initial pressures and temperatures are determined. Flame transition from the gas to the liquid phase of TFE is investigated. Liquid TFE is demonstrated to be virtually nondetonable. The fuel-lean flammability and detonability limits of TFE-air mixtures under normal conditions are demonstrated to be identical, 12.2 vol %.     

Material structure-composite morphology-photovoltaic performance relationship for organic bulk heterojunction solar cells

Conjugated PPV-PPE copolymer has been investigated in organic solar cells in combination with twelve different fullerene derivatives. It was shown that the length of solubilizing alkyl chains in the fullerene derivative structures correlates well with the performance of photovoltaic cells.     

Arbuzov chemistry with chlorofullerene C(60)Cl(6): a powerful method for selective synthesis of highly functionalized [60]fullerene derivatives

We report Arbuzov-type reactions of chlorofullerene C(60)Cl(6) with trialkyl phosphites producing highly functionalized fullerene derivatives C(60)[P(O)(OR)(2)](5)H with high yields. The designed family of [60]fullerene phosphonic acids and their esters showed unusual properties which might find valuable material science applications.     

Electrochemistry of methanofullerenes embedded in hydrophobic ammonium cation films

The electrochemical behavior of several methanofullerenes, including methyl-C₆₁-propionic acid esters (Ph-C₆₁-(CH₂)₂COOC _n H_{2n + 1}, n = 1–4, 8), in tetraoctyl- and didodecyldimethylammonium bromide films on conducting glass was studied. A cyclic voltammetry study showed that the introduction of methanofullerene derivatives in a cation matrix led to redox transformations of these compounds at potentials accessible for aqueous solutions. The shift of their formal potentials toward positive values is mainly caused by the electrostatic interactions of the reduction products (methanofullerene anions) with the matrix cations. The chemical stability of the reduction products is provided by their hydrophobic microenvironment in the matrix in all cases. This makes it possible to perform quasireversible redox transformations in neutral aqueous media. The duration of the adjustment of the structure of the coating depends on the solvent used for its preparation, the length of the alkyl radical in the ester group of methanofullerene, and the length of the alkyl chain between the cyclopropane fragment and the COOC _n H_{2n + 1} group. The redox potentials of methanofullerene Ph-C₆₁-(CH₂)₂COOC₂H₅ incorporated in the didodecyldimethylammonium bromide film lie in the range of higher negative values relative to the potentials of the compound in the tetraoctylammonium bromide film.     

A simple model for a two-stage chemical reaction with diffusion

We analyse the evolution of a two-stage chemical reaction betweentwo neighbouring plumes of reactants. Under the assumption thatthe plumes are approximately Gaussian we derive a system ofordinary differential equations for the total amount, the centroidand the variance of each reactant. We compare the solution ofthese equations with full numerical simulation of the reaction.Excellent agreement is obtained, with solution of the near-Gaussianmodel requiring considerably less computational effort thanthe full simulations. Of key importance is the yield of thereaction, and we discuss this feature in particular.     

Electromasstransfer in Electrolytic Solutions

It is shown that a frame of reference—solvent provides a chance to determine only the overall electromasstransfer, whereas employing a frame of reference—solution allows one to separately measure parameters of electrotransfer and mass transfer. A mechanism of formation of stable ionic boundaries in electrolytic solutions upon passing a constant electric current is discussed. A technique for the determination of velocities of solutions moving to and from an ionic boundary under the action of a pressure gradient emerging in the vicinity of the boundary is proposed.