The effect of complexing processes on energy transfer Tl+→Gd3+ and Tl+→Tb3+ in glass

T. Shevchenko Kiev University, 252022 Kiev, Pr. Akad. Glushakova, 6, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 62, No. 3, pp. 192–196, May–June, 1995.     

Determination of the rate of nonradiative relaxation,processes on excitation of electronic states in YAG:Nd3+

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 54, No. 2, pp. 229–233, February, 1991.     

Quick Determination of the Total Content of Aromatic Hydrocarbons in Reformer Naphthas by <Superscript>1</Superscript>H NMR Spectroscopy

A procedure for fast determination of the total content of arenes in reformer naphthas by ¹H NMR spectroscopy was developed and tested. Their content is determined from the ratio of the integral intensities of the signals of aromatic protons and alkane methyl protons, using a calibration plot constructed on the basis of GLC data.     

Modern state of the catalytic reforming of petrol fractions. Experience of manufacture and industrial exploitation of reforming catalysts of the PR series

Analysis of the modern state of catalytic reforming is performed. Comparative assessment of the efficiency of various technologies of the process is given and their distribution in Russia and abroad is shown. Experience of the modernization of reforming installations with periodic catalyst regeneration is summarized. The state of manufacture of reforming catalysts in our country and accumulated experience of the development of catalysts of the PR series are presented. Results of industrial exploitation of new domestic reforming catalysts are shown. On this basis comparative assessment of Russian and imported catalysts is given. Original Russian Text D.I. Kiryanov, M.D. Smolikov, V.V. Pashkov, A.G. Proskura, E.V. Zatolokina, I.E. Udras, A.S. Belyi, 2007, published in Russkii Khimicheskii Zhurnal, 2007, Vol. 51, No. 4, pp. 60–68.     

Nonexponentially Decaying Electromagnetic Waves Localized at the Boundary of Anisotropic Metal–Dielectric Structures

The possibility of the existence of a special class of surface electromagnetic waves with amplitude decreasing nonexponentially as they pass into an anisotropic metal–dielectric structure that borders the isotropic dielectric has been shown. The dispersion equation describing the propagation of such special surface waves has been obtained, and their attenuation coefficients and formula for electric and magnetic fields in contacting media have also been found. The expressions for the longitudinal and transverse components of the Poynting vector and volume density of electric and magnetic energy of special surface waves have been obtained. Numerical calculations for the layered metal–dielectric nanostructure that is described by a uniaxial tensor of effective dielectric permeability have been carried out Decaying.     

Spreading of block copolymer films and domain alignment at moving terrace steps

We investigate spreading of phase separated copolymer films, where domain walls and thickness steps influence polymer flow. We show that at early stages of spreading its rate is determined by slow activated flow at terrace steps (i.e., thickness steps). At late stages of spreading, on the other hand, the rate is determined by the flow along terraces, with diffusionlike time dependence t(-1/2). This dependence is similar to de Gennes and Cazabat's prediction for generic layered liquids [P. G. de Gennes and A. M. Cazabat, C.R. Acad. Sci. Paris II 310, 1601 (1990)], as opposed to the classical Tanner's law of drop spreading. We also argue that chain hopping at the spreading terrace steps should lead to the formation of aligned, defect-free domain patterns on the growing terraces.     

Photoinduced Electron Transfer From Carbazole to Halomethanes in a Gas Phase

Intermolecular photoinduced electron transfer (PET) in a gas phase was studied using carbazole vapor fluorescence quenching by halomethanes (CHCl₃, CH₂Br₂, CCl₄, CHBr₃). The fluorescence quenching rate constants k _q changing from 2.3·10⁵ sec^–1·torr^–1 in mixtures with CHCl₃ to 4.6·10⁶ sec^–1·torr^–1 in mixtures with CHBr₃ at a constant temperature of 403 K were estimated. The dependence of the carbazole fluorescence decay rates in the presence of halomethanes on the free energy change G during transfer of the electron from carbazole to halomethanes is considered. It is suggested to take into account the influence of the vibrational energy of the carbazole molecule E _vib and its temperature changes in estimation of the G values. The differences between PET in the gas and liquid phases were analyzed. It is found that for mixtures with CCl₄ and CHBr₃ the negative temperature dependence of k _q is observed, when the decay rates and efficiencies of the intermolecular PET decreased with temperature increase in the range 403–573 K, i.e. these mixtures the electron transfer is not a barrier-restricted process.