Fluorescence induced by double K capture

Features of double fluorescence spectra generated by double K capture in the ⁷⁸Kr atom are considered. The energies and bandwidths of fluorescence are calculated. The latter are approximately four times wider for the first and second quanta, respectively, relative to the vacancy hole in the K shell. The fluorescence yields are calculated as well. They are 0.77 and 0.61 for the first and second quanta, respectively, and 0.47 for both quanta simultaneously.     

Upper critical field of niobium nitride thin films

The temperature dependences of the superconducting transition of niobium nitride (NbN) thin films have been investigated via the first harmonic of the voltage in dc magnetic fields of up to 8 T. The temperature dependence of the second critical field of NbN has been determined. The parameter responsible for the effect of spin paramagnetism in this material and the temperature dependence of the upper critical field that describes well the experimental data have been found in terms of the Werthamer–Helfand–Hohenberg (WHH) theory. The key parameters of the superconductor have been estimated from the transport and optical measurements.     

Synthesis and structure of new composite hydrogels based on poly(N-vinyl caprolactam) with nanosized anatase

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Interferometric method for estimating the sound source velocity in an oceanic waveguide

The noise immunity of an algorithm for estimating the radial component of sound source velocity, based on the data on frequency shifts of field interferencemaxima, has been investigated. A limiting estimate for the input signal-to-noise ratio, which determines the algorithm efficiency, is obtained. The results of computational and natural experiments are reported.     

The development and the study of cyanourethane laquer compositions and coatings based on them

A procedure was developed for preparing cyanourethane laquer compositions based on polyisocyanates, polyesters of various structures, and dicyanodiamide. The influence of the polyester structure and component ratio on the properties of the cured laquer coatings was examined, and the compositions allowing preparation of corrosion- and heat-resistant laquer coatings were determined.     

Synthesis of thiacyanine dyes containing coumarin moieties at benzothiazole rings

New bischromophoric dyes (thiacarbocyanine and thiadicarbocyanine) containing coumarin moieties at each of the two benzothiazole systems, as well as monomethinecyanine containing coumarin moiety at only one heterocyclic system, manifest significant batho-chromic shift compared to relative coumarin-free dyes.     

Synthesis of New 4,4a-Dihydroxanthones via [4+2]-Cycloaddition Reaction

Russian Journal of General Chemistry - The effect of electronic properties of substituents in the reactants on the [4+2]-cycloaddition of 3-vinyl-chromen-4-ones (dienes) and N-vinylpyrrolidines...     

Novel derivatives of 3,5-di-tert-butylpyrocatechol with pharmacophore substituents

Russian Chemical Bulletin - New potentially bioactive derivatives comprising spatially hindered pyrocatechol linked to hydrazine, acid hydrazides (including isoniazid), and acetylcysteine by a...     

Complexation and transport of amino acid esters and their salts with synthesised chiral novel aza crown ether derivatives

The syntheses of four aza-15-crown-5 ethers bearing phenyl and phenoxymethyl moieties attached to a stereogenic centre on the crown ring were achieved. Macrocycles have exhibited strong binding ability (K_a = 5364–12,969 M^? 1) and modest enantiomeric discrimination towards the enantiomers of amino acid methyl ester salts by UV titration method in CHCl₃ at 25°C. Computer modelling results supported experimental data providing a detailed understanding of the molecular recognition mode between hosts and guests and the likely binding sites involved. Macrocycles were used for chiral discrimination of amino acids in their zwitterionic forms or as potassium and sodium salts in transport experiments across a bulk chloroform membrane with satisfactory selectivity.     

Formation kinetics of nanoparticles as the basis for simulating the generation mechanism of Liesegang rings in gels

An approach has been proposed for determining the space-time parameters of the formation process of Liesegang rings. This approach relates the processes of the formation of nanoparticles and dense periodic precipitates from them. Dynamic light scattering is employed to reveal periodic variations in the intensity of light scattered by nanoparticles with different sizes, from which Liesegang rings are formed. A relationship between the periods of the variations in the intensity of light scattered by nanoparticles (microscopic process) and the times of the formation of Liesegang rings as a whole (macroscopic process) has been found.