Spectral Luminescence Properties of Potassium Aluminophosphate Glass Doped with Four-Valence Vanadium Complexes

Potassium aluminophosphate glass with the composition 30 K₂O-20 Al₂O₃-50 P₂O₅ (wt %) doped with four-valence vanadium was prepared and analyzed. Some physicochemical properties of the glass obtained and its absorption and luminescence spectra were investigated at 300 K. The existence of oxovanadium ions in the prepared glass was proved on the basis of the electronic absorption data. The bands observed in the electronic absorption spectrum were assigned to the e→b ₁ and e→a ₁ transitions. Intense luminescence of four-valence vanadium in the wavelength range 800–1100 nm was found. The average luminescence decay time amounts to 12 μs. __________ Translated from Optika i Spektroskopiya, Vol. 96, No. 6, 2004, pp. 926–928. Original Russian Text Copyright ? 2004 by Batyaev, Linnikov, Lipatova.     

Structural investigations in the series of spiro(thia)chromans

A comparative assessment was made of the reactivity of carbonyl-containing spirohydrochromans in their reaction with hydrogen sulfide under the conditions of acid catalysis. The special features of the structure of one of the obtained condensed spiro(thia)chromans are examined on the basis of the results from x-ray crystallographic analysis, the¹³C NMR spectra, and quantum-chemical calculations. N. G. Chernyshevskii Saratov State University, Saratov 410026, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1340–1345, October, 1998.     

Effect of Ultrasonic Field on the State of Starch Hydrogels

Some fundamental aspects of how the primary structure of starch hydrogels with concentration of 1 to 8 wt % disintegrates in an ultrasonic field are discussed. The effect of ultrasonic vibrations on the basic characteristics of starch hydrogels: degree of grain cleavage, viscosity, transparence, and phase composition, is analyzed.     

Adsorption layers of surface-active substances and their influence on polyurethane network formation

The study of polyurethane systems cured in the presence of surface-active substances (SASs) proves that surfactants call forth the structural and kinetic changes in the reaction system. It is shown that surfactant decreases the viscosity of these systems in the early stages of reaction, shifting the beginning of structural gel formation to the higher degrees of NCO-group conversion. The reaction rate is shown to be a complex function of surfactant concentration. The binary polyether-surfactant system was studied by IR spectroscopy and surface tension measurement. The data prove that intermolecular and intramolecular H bonds in the system are redistributed at all surfactant concentrations but 0.03 and 0.15%. According to our calculations for surfactant adsorption layers at the polyether-air interface, ΔS values do not depend on temperature at surfactant concentration 0.03% whereas at 0.15% ΔS and ΔH values are maximum. The results obtained by different methods are well correlated and suggest that kinetic effects are due to redistribution of H bonds under the influence of conformational changes in surfactant structure.     

Rate of Acid Hydrolysis of Starch as Influenced by Intensive Mechanical Effects

The influence of ultrasonic cavitation on the rate of acid hydrolysis of gelatinized starch under the action of ultrasonic field or strong mechanical stresses in a rotary-pulsating activator is discussed. The dependences of the hydrolysis rate on the starch concentration, acid content, temperature, and intensity of mechanical action on the system are analyzed.     

Adsorption of Anionic Metallophthalocyanines on Submicron Chitosan-Sulfate Particles in Aqueous Dispersions

Russian Journal of General Chemistry - The kinetic and capacity of the anionic metallophthalocyanines adsorption on the submicron chitosan-sulfate particles in aqueous dispersions were examined....     

Gas-Phase Hydrodechlorination of Chlorobenzene over Alumina-Supported Nickel Catalysts: Effect of Support Structure and Modification with Heteropoly Acid HSiW

Kinetics and Catalysis - The physicochemical and catalytic properties of 6%Ni/Al2O3 catalysts in the gas-phase hydrodechlorination of chlorobenzene (CB) are studied. The catalysts are synthesized...     

Formation of the dispersed phase in mixed solutions of chitosan and magnesium sulfate

Specific features of formation and the composition and characteristics of dispersed phase particles in mixed dilute solutions of chitosan and magnesium sulfate, containing no surfactants, were studied. The component molar ratio, \(\nu _{SO_4 } :\nu _{NH_2 }\) , is the factor exerting the strongest influence on the formation rate and characteristics of chitosan sulfate particles. With an increase in the fraction of sulfate ions in the initial solution, the particle size decreases and their ζ-potential increases. The \(\nu _{SO_4 } :\nu _{NH_2 }\) molar ratio in chitosan sulfate particles only slightly depends on the composition of the initial mixed solution and varies within 0.40–0.44.     

Effect of filler nature and mechanical activation on rheological properties of suspensions based on chitosan solutions

Effect of the nature of a dispersed solid filler and mechanical treatment in a rotary-pulsatory apparatus on rheological properties of suspensions based on a natural polyelectrolyte chitosan was studied.