Hetrocyclic Thiones and Their Analogs in Reactions of 1,3-Dipolar Addition: VI. Reactions of Thiazoline-2-thione with Nitrile Imines

Reactions of thiazoline-2-thione with C,N-disubstituted nitrile imines were investigated. The reaction products are substituted 2-(1,3,4-thiadiazol-2-ylideneamino)ethanethiols and bis[2-(1,3,4-thiadiazol-2-ylideneamino)ethyl] disulfides. The reaction of thiazoline-2-thione with a double excess of nitrile imine did not considerably change the process route. The structure of compounds obtained was proved by X-ray diffraction analysis. A presumable scheme is given describing the formation of compounds obtained.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 5, 2005, pp. 776–782.Original Russian Text Copyright © 2005 by Firsova, Dolgushina, Polukeev, Ioannisyan, Zavodnik, Stash, Bel’skii, Galishev.     

Riemann surface of quasimomentum and scattering theory for the perturbed Hill operator

The perturbed Hill operator , p(x+1)=p(x), q(x)L₁(-,) is considered. An eigenfunction expansion theorem is obtained and the scattering theory is constructed. A new spectral variable, the so-called quasimomentum is introduced. The Riemann surface of the quasimomentum is constructed and investigated.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 51, pp. 183–196, 1975.     

Mechanochemical Synthesis as an Alternative Effective Technique for the Preparation of the Composite Catalysts

Kinetics and Catalysis - —Mechanochemical synthesis in a ball mill was applied for the nanocomposite Cu(CuO)–CeO2 catalyst preparation from CeO2 and following dopants: Cu metal and...     

Electron scattering in the monolayer graphene with a band-asymmetric annular potential well

Electron scattering in the monolayer graphene has been considered within the framework of our model of short-range defects proposed earlier. Electronic properties are determined by the Dirac equation for the two-component spinor wave function. Perturbation is modeled by the annular well with a band-asymmetric potential. Band-asymmetry of the potential stems from the local structure defect and leads to the mass (gap) perturbation in the Dirac equation. Transitions between the K and K’ critical points in the Brillouin zone are neglected, which is valid provided that the short-range perturbation has a finite radius. Exact explicit formulas for the scattering matrix have been derived. Results are presented in terms of the scattering phases and in the geometrical form of a relation between some 2-vectors. The characteristic equation for the bound and resonance states has been obtained in the form of an orthogonality condition. An approximate calculation of observables in terms of the scattering theory results is outlined.     

Film-forming synthetic polyelectrolytes for phosphogypsum modification

Methods for deposition of film-forming water-insoluble polycomplexes onto the surface of granulated phosphogypsum were developed. The effect of the resulting films on the physicochemical and performance characteristics of the phosphogypsum granules containing crystalline solvates of calcium sulfate was examined, as well as on leaching from the granules of various admixed components.     

Modification of phosphogypsum granules by humic acids

Methods for introducing humic acid into granular multicomponent phosphogypsum-based ameliorants are elaborated. The influence of modifying additives of humic acids on the physicochemical and performance characteristics of phosphogypsum granules containing crystalline solvates of calcium sulfate, and on the process of leaching different extrinsic components from the granules, were studied.     

Congruently melting compositions in the series of solid solutions R1 ? xSrxF3 ? x (R = La-Nd, 0 ≤ x ≤ 0.15) with tysonite structure (Refinement by directional crystallization)

Congruently melting compositions in the series of solid solutions R _{1 − x} Sr_xF_{3 − x} (R = La-Nd with a defect structure of the tysonite type (LaF₃) were found by the comparing the densities (determined by hydrostatic weighing) of the top and bottom parts of the single crystals grown using the Bridgman method. Measurement errors are analyzed. __________ Translated from Kristallografiya, Vol. 48, No. 5, 2003, pp. 940–944. Original Russian Text Copyright ? 2003 by Krivandina, Zhmurova, Glushkova, Firsova, Shtyrkova, Sobolev. Dedicated to the 60th Anniversary of the Shubnikov Institute of Crystallography of the Russian Academy of Sciences     

Isomerization [trans-B20H18]2– → [iso-B20H18]2– during silver(I) complexation with triphenylphosphine

The trans–iso isomerization of the dimeric borohydride cluster anion [B₂₀H₁₈]^2– in the course of the silver(I) complexation reaction with triphenylphosphine has been described for the first time. The isomeric complexes [Ag₂(Ph₃P)₆[trans-B₂₀H₁₈]] and [Ag₂(Ph₃P)₆[iso-B₂₀H₁₈]] have been isolated and characterized by physicochemical methods. The structures of the compounds have been determined by X-ray crystallography.     

Effect of the nanoparticle size of supported copper-containing catalysts on their activity in the selective oxidation of CO in an excess of H<Subscript>2</Subscript>

The catalytic properties of systems prepared by the supporting of CuO onto CeO₂, ZrO₂, and Zr_0.5Ce_0.5O₂ with particle sizes of 15–25 nm (nitrate pyrolysis (p)) and 5–6 nm (microemulsion method (me)) in the reaction of CO oxidation in an excess of H₂ were studied. In the latter case, the supports had an almost homogeneous surface and a small number of defects. The catalytic activity of (me) and (p) supports was low and almost the same, whereas the catalytic activity of CuO/(CeO₂, ZrO₂, and Zr_0.5Ce_0.5O₂)(me) samples was lower than that of CuO/(CeO₂ and ZrO₂)(p). The maximum CO conversion (∼100% at 125°C) was observed on 5% CuO/CeO₂ (p). The CO and CO₂ adsorption species on (p) and (me) catalysts were studied by TPD. Differences in the compositions of copper-containing centers on the surfaces of (p) and (me) systems were found using TPR. The nature of the active centers of CO oxidation and the effect of support crystallite size on the catalytic activity were considered.     

An inverse scattering problem for a perturbed Hill's operator

We consider the inverse scattering problem for the operator L=?d²/dx²+p(x)+q(x), x ∈ R¹. The perturbation potential q is expressed in terms of the periodic potential p and the scattering data. We also obtain identities for the eigenfunctions of the unperturbed Hill's operator L₀=?d²/dx²+p(x).