Structural relaxation of excited molecules of heteroaromatic compounds

The results of investigation into structural relaxation in the excited singlet state are summarized for a wide range of heteroaromatic fluorophores and some of the heteroaromatic cations. Particular attention is paid to the substantiation of the modern competitive models of structural relaxation (TICT and PICT). The spectral-and-kinetic parameters of the compounds and the rate constants for the formation of relaxed charge-transfer states are tabulated.     

Convolution equations and the local Pompeiu property on symmetric spaces and on phase space associated to the Heisenberg group

In this paper, we present new uniqueness results related to geometric aspects of mean periodicity on various homogeneous spaces. Among these results, we point out the equivalence of the local and the global Pompeiu property for arbitrary families of compactly supported distributions, the solution of the local Pompeiu problem for the class of non real-analytic functions, and local versions of the two-radii theorem on symmetric spaces of arbitrary rank.     

New Integral Representations for a Hypergeometric Function

We obtain new integral representations for a hypergeometric function.     

Inversion temperature for adiabatic evaporation of liquid into an air-steam mixture

This paper deals with adiabatic evaporation of various liquids into an air-steam mixture and pure superheated steam. The focus is made on the inversion temperature, which means that the rate of liquid evaporation into an air-steam mixture (superheated steam) becomes equal to the rate of evaporation into dry air. A simple analytical solution for finding of inversion temperature was derived, and the required conditions of existence of the given phenomenon are found. The influence of parameters of the main flow (vapor quantity, pressure, and flow regime) on the value of inversion temperature is analysed. It is shown that consideration of the influence of injection flow on relative function of heat transfer for inversion temperature definition of ethanol, acetone, and benzene is necessary. A comparison with numerical modelling was made to estimate the analytical solution accuracy. The work was financially supported by the Russian Foundation for Basic Research (Grants Nos. 05-02-16478 and 05-08-17981), and by President of the Russian Federation (Grant NSh-6965.2006.8).     

Temperature dependence of the magnetic properties and magnetoimpedance of nanocrystalline Fe<Subscript>73.5</Subscript>Si<Subscript>16.5</Subscript>B<Subscript>6</Subscript>Nb<Subscript>3</Subscript>Cu<Subscript>1</Subscript> ribbons

The temperature dependences of the magnetic properties and the magnetoimpedance effect of soft magnetic nanocrystalline Fe_73.5Si_16.5B₆Nb₃Cu₁ alloy ribbons are studied in the temperature range 24–160°C. A high temperature sensitivity of the impedance and the magnetoimpedance effect of the ribbons are detected in the ac frequency range 0.1–50 MHz. At an ac frequency of 50 MHz, the change in the impedance reaches 0.2 Ω/°C (0.5%/°C) in the temperature range 85–160°C. When the temperature increases, a monotonically decreasing character of the dependence of the magnetoimpedance effect on the applied magnetic field changes into a dependence having an increasing initial segment. The effect of temperature on the magnetoimpedance properties of the soft magnetic nanocrystalline ribbons is shown to result from temperature-induced changes in their electrical conductivity, magnetization, and effective magnetic anisotropy.     

Induced Intersystem Crossing at the Fluorescence Quenching of Laser Dye 7-Amino-1,3-Naphthalenedisulfonic Acid by Paramagnetic Metal Ions

The fluorescence and triplet state quenching of 7-amino-1,3-naphthalenesulfonic acid by paramagnetic metal ions have been investigated in an aqueous medium. The basic mechanism of the fluorescence quenching involves the static and dynamic electron transfer to the paramagnetic cation. The induced S₁→T₁ intersystem crossing at fluorescence quenching of the fluorophore by Cu²⁺ cation has been found. There is a correlation between triplet state quenching rate constants and values of the efficient paramagnetic susceptibility and spin of the cations. The rate constants for the quenching pathways have been calculated.     

Magnetic properties and the magnetoimpedance effect of nanostructured Fe<Subscript>73.5</Subscript>Si<Subscript>16.5</Subscript>B<Subscript>6</Subscript>Nb<Subscript>3</Subscript>Cu<Subscript>1</Subscript> ribbons with induced magnetic anisotropy

The structure and magnetic properties and the magnetoimpedance effect of nanocrystalline Fe_73.5Si_16.5B₆Nb₃Cu₁ alloy ribbons, obtained from the amorphous state by annealing under different conditions, were comparatively analyzed. Despite the similarity of the samples’ structural states and the processes of their quasi-static magnetization reversal, the features of the magnetoimpedance effect are indicative of significant differences in the processes of their dynamic magnetization.