Function of the Non-Crystalline X-Ray Amorphous Phase of Highly Dispersed Powder of CaO in Adsorption of CO2 and H2O

Russian Journal of General Chemistry - Highly dispersed CaO has been synthesized by heating an aqueous solution of calcium nitrate and D-glucose up to 800°C. Calcium oxide is formed with an...     

On the Statistics of Partial Quotients of Finite Continued Fractions

We refine the remainder estimate in the asymptotic formula, earlier obtained in a joint paper with V. A. Bykovskii, for Arnold's problem about Gauss-Kuzmin statistics.     

Study of the absorption spectra and ionic equilibria of cationic-anionic polymethine dyes

The absorption spectra of a number of cationic-anionic polymethine dyes in polar, low-polarity, and nonpolar solvents were studied. It was established that in polar solvents the absorption spectra represent the sum of the absorption spectra of the cation and anion, whereas in nonpolar and low-polarity solvents, in many cases the appearance of a short-wave absorption band is observed, due to interaction of the chromophores of the cation and anion in ion pairs. In solvents of intermediate polarity (for example, in chloroform and ethyl acetate), a concentration dependence of the absorption spectra is observed, determined by the equilibria of ionic dissociation. The ionic dissociation constants of a number of cationic-anionic dyes in chloroform and ethyl acetate were determined by a conductometric method. The thermodynamic data obtained are compared with the spectral data.N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117977 Moscow. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2524–2532, November, 1992.     

J Aggregation of Thiacarbocyanine in Aqueous Gelatin Solutions

The aggregation processes of 3,3′-disulfopropyl-4,4′,5,5′-dibenzo-9-ethylthiacarbocyanine betaine were studied in aqueous gelatin solutions. Gelatin molecules were shown to favor the formation of J aggregates from dye dimers according to the block mechanism. Acidic gelatins much stronger favor J aggregation of the dye than alkaline and, especially, modified gelatins. High contents of microgels and high-molecular-mass fractions in gelatin retard the formation of long-wavelength aggregates.     

Adsorption of H3PW12O40 by porous carbon materials

Adsorption of H₃PW₁₂O₄₀ from water and organic oxygen-containing solvents (AcOH, Me₂CO, MeOH) by carbon mesoporous materials, viz., Sibunit and catalytic filamentous carbons (CFC), was studied. The amount of irreversibly sorbed heteropolyacid is 50—100 mg g^–1 of support and decreases in the series of solvents: H₂O > Me₂CO > AcOH > MeOH. The adsorption capacity of CFC depends on the specific surface, total pore volume, and microstructure of the CFC fiber.     

Solid Phase Interaction of the Recondensed Finely Dispersed Mixture (VC0.40O0.53–C) with Titanium Hydride

Russian Journal of Applied Chemistry - The processing of industrial waste and highly hazardous substances using extreme techniques of formation, in addition to else, of nanocrystalline materials,...     

The lower bound for the number of local minima of integral lattices

A lower bound for the maximal number of local minima of integral lattices with preassigned determinant is derived. This bound coincides with the upper one up to a constant. __________ Translated from Fundamentalnaya i Prikladnaya Matematika, Vol. 11, No. 6, pp. 9–14, 2005.     

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.