Synthesis and electrophysical characteristics of VO2-based nanostructures with a complicated architecture on a silicon surface

Nanofilms of complicated architecture based on VO₂ and containing chromium were synthesized by the molecular layering method. The study of electrophysical characteristics of vanadium dioxide nanocrystallites and of VO₂-containing chromium has shown that semiconductor-metal phase transitions appear in the ranges of 130–160 and 100–110 K, respectively. The introduction of a transition-element ion in the nanostructures based on VO₂ affects the phase transition characteristics.     

Synthesis of binder-free granulated MOR-type zeolite with hierarchic pore structure

A procedure was developed for preparing an aluminosilicate with a hierarchic pore structure and granules in the form of united polycrystalline concretions of MOR-type zeolite in the Na form. The procedure includes the step of mixing of MOR-type powdered zeolite with kaolin and white carbon black, granule forming, granule calcination, and crystallization in an autoclave in a sodium silicate solution.     

DC Electrical Conductivity of the Direct Electrochemically Synthesized Polythiophene Metal Complexes

Electrochemical anodic oxidation of a metal anode in an acetone solution of 2,5-diamino-3,4-dicyanothiophene gave the polythiophene metal complexes of Co, Ni, Cu, Zn, Cd, and Sn. Chemical analyses, as well as FTIR and electronic spectral data, are presented to confirm the formulation of the isolated materials. DC electrical conductivity measurements of the polymer complexes were measured in the range 300–500 K in the annealed and 5% doped forms. The products gave electrical conductivity in the semi-conducting region that increased by heat.     

On the construction of a quadratic Lyapunov function with given properties

We analyze the possibility of choosing the parameters of a Lyapunov quadratic function so as to ensure the negative definiteness of its first derivative (or first difference) with a given margin.     

Effect of concentration on the structure of aqueous solutions of gadolinium chloride and gadolinium nitrate as probed by X-ray diffraction

Aqueous solutions of gadolinium chloride and gadolinium nitrate are studied by X-ray diffraction over wide ranges of concentrations under standard temperature and pressure. Small-angle peaks on measured scattering intensity curves are interpreted. Small-angle peaks are found not only on the intensity curves for concentrated solutions, but also on those for dilute systems, and this proves that these systems retain a long-range order. Diverse types of ion-ion interactions are shown to be the major contributors to the overall scattering pattern that are responsible for the appearance of pre-peaks.     

Transformations of several monoterpenoids in the presence of aldehydes in supercritical solvents

The reactivity of verbenol epoxide and isopulegol in supercritical solvents in the presence of aromatic aldehydes was studied using a flow type reactor and a heterogeneous catalyst (Al₂O₃) or no catalyst. The intramolecular transformations or interactions of reagents with the solvent prevailed in all cases; the yield of the products of intermolecular reactions of terpenoids with aldehydes was up to 1%. The aldehydes did not interact with verbenol epoxide but produced a considerable effect on the distribution of its isomerization products.     

Synthesis of oxazolidinylphosphine chalcogenides from aminoethyl vinyl ethers

N-(2-Vinyloxyethyl)phosphinothioamides and -phosphinoselenoamides prepared by oxidative cross-coupling of 2-vinyloxyethylamine with secondary phosphine chalcogenides undergo thermal (75–100 °C) cyclization into the corresponding 3-(diorganylchalcogenophosphoryl)-2-methyl-1,3-oxazolidines in 80–90% yields.