Electrical Conductivity of Cryptocrystalline Forms of Silica

Crystallography Reports - The electrical conductivity of natural samples of exogenous silicides has been studied. In the temperature range of 515?700 K, the conductivity increases from 1.1...     

Experimental and Theoretical In Situ Spectral Magneto-Ellipsometry Study of Layered Ferromagnetic Structures

JETP Letters - The influence of antiadiabatic phonons on the superconducting transition temperature is considered within Eliashberg-McMillan approach in the model of discrete set of (optical)...     

An Experimental Study of the Influence of a Magnetic Field of an Elongated Solenoid on Metal Shaped-Charge Jets Stretching

Technical Physics - The results of an experimental study of the influence of a longitudinal magnetic field of an elongated solenoid on stretching of metal shaped-charge jets in free flight are...     

Spectral Standards Based on Glasses Activated with Rare-Earth Element Ions for the Calibration of Fluorescence and Raman Spectrometers

Optics and Spectroscopy - The results of development of fluorescence calibration standards based on phosphate matrix glass activated with ions of rare-earth metals are presented. The calibration...     

Calculating the thermodynamic characteristics of hydrophobic hydration of chromium(III) and cobalt(III) tris-acetylacetonates in water and regularities of their solvation in aqueous alcoholic solvents

Based on the scaled-particle theory, the Gibbs energy of the formation of cavities in the structure of water and some alcohols are calculated for the processes of dissolution of cobalt(III) and chromium(III) tris-acetylacetonates. The contribution from the hydrophobic hydration of the tris-acetylacetonate molecules in water is calculated. The location of the inversion area is clarified for a number of aqueous alcoholic solvents, and the effect the solvent’s macrophysical parameters have on the patterns of tris-acetylacetonate solvation is analyzed.     

Colloidal dispersions of tantalum trisulfide: syntheses and characteristics

Stable colloidal solutions with the TaS₃ content ≈ 1 mmol L^–1 were obtained by the ultrasonic treatment of TaS₃ in MeCN and DMSO. The detailed analysis of the particle size distribution in colloidal dispersions and their stability was carried out using data of atomic force microscopy and photon correlation spectroscopy for TaS₃/MeCN. The data of powder diffractometry and Raman spectroscopy show that the films prepared from colloidal dispersions of TaS₃ retain the crystal structure of the initial tantalum trisulfide.     

Encapsulation-Controlled Photoisomerization of a Styryl Derivative: Stereoselective Formation of the Anti Z-Isomer in the Cucurbit[7]uril Cavity

The photochemical isomerization of a styrylpyridinium dye ( SP ) bearing an unsymmetrically attached benzo-15-crown-5 ether has been studied in aqueous solution in the absence and presence of cucurbit[7]uril (CB[7]). The detailed analysis of the UV/Vis and NMR spectra showes that the isomeric composition of the photostationary mixtures of SP can be modulated by the host-guest complexation with CB[7]. It was found that steric hindrance caused by encapsulation of SP in the host cavity induces the exclusive formation of the anti conformer of Z- SP in contrast with the mixture of both anti and syn conformers obtained during photoisomerization of the dye without CB[7]. Remarkably, the displacement of anti Z- SP from CB[7] does not lead to the transformation of the anti Z-isomer into the syn Z-isomer pointing out the conformational memory of the system. The results provide an interesting example of the supramolecular stereorecognition by the achiral CB[7] host.     

Hydrogen Peroxide Decomposition Catalysts Used in Rocket Engines

Russian Journal of Applied Chemistry - The results of the development and studies of heterogeneous catalysts for decomposition of highly concentrated hydrogen peroxide used as monopropellant and...