On the solvability of physically nonlinear problems of Thermoelasticity

We study the problem of existence and uniqueness of generalized solutions of nonlinear vector boundary-value problems arising in the physically nonlinear theory of thermoelasticity. We prove the convergence of iteration processes in the space W ¹ ₂.     

Reactions of 4-Hydroxy-5-methyl(phenyl)-2-styryl-6H-1,3-oxazin-6-ones with Nucleophiles

4-Hydroxy-5-methyl(phenyl)-2-styryl-6H-1,3-oxazin-6-ones react with hydrazine and phenylhydrazine to give the corresponding 3,5-substituted triazoles. Treatment of the title compounds with ethanol and methanol leads to formation of N-cinnamoylmalonamates. The structure of the products was confirmed by the IR and ¹H and ¹³C NMR spectra.     

Structural and Kinetic Features of Formation of High-Strength Epoxy-Amine Cross-Linked Polymers by Combined Polycondensation-Polymerization Process

To control the structural contributions of the polycondensation and polymerization curing of epoxy resins, the curing kinetics of the composites diepoxide-tertiary amine and diepoxide-(primary + tertiary) amines is studied by the isothermal calorimetry.     

Investigation of the distribution of the negative charge in anionic cyanine dyes by means of lanthanide shift reagents

It was established by PMR with lanthanide shift reagents that the charge in anionic cyanine dyes with a linear chromophore is concentrated at the ends of the polymethine chain, while in compounds containing a vinylene group in the chromophore it is concentrated in the region of the five-membered ring. The results are compared with the data from¹³C NMR spectroscopy and relaxation measurements in the presence of Gd(fod)₃. The validity of the conclusions is also considered.Kiev University. Institute of Organic Chemistry, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Teoreticheskaya i Éksperimental'naya, Vol. 27, No. 2, pp. 197–201, March–April, 1991. Original article submitted December 20, 1989.     

Cleavage of α-oxides by trimethyliodosilane

Conclusions The cleavage of the ethylene and propylene oxides by trimethyliodosilane proceeds easily to give trimethyl(2-iodoethoxy)silane and a mixture of trimethyl(2-iodopropoxy) silane and trimethyl(1-iodoisopropoxy)silane in a 12.5 ratio.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2623–2624, November, 1978.     

X-Ray Powder Diffraction Studies of Polyhydrates of Cross-Linked Tetraisoamylammonium Polyacrylates

X-ray powder diffraction studies were performed of the polyhydrates, formed at positive temperature in swelled grains of carboxylic cation-exchange resins in the form of tetraisoamylammonium (cross-linked tetraisoamylammonium polyacrylates, differing in the degree of cross-linking: 1, 2 and 3%). It was shown that the polyhydrates exist as the crystalline phase under specific conditions, determined earlier by DTA technique. Diffraction patterns of the samples, recorded at the temperature +3 ± 1 °C, indicate that the polyhydrates crystallize in hexagonal symmetry, the unit cell parameters are close to a=12.25 Å, c=12.72 Å and do not depend significantly upon the degree of cross-linking. The suppositions were made concerning the size of hydrate crystallites, formed in the swelled grains of the studied resins.This revised version was published online in July 2005 with a corrected issue number.     

Cleavage of di- and trioxacyclohexanes by trimethyliodosilane

Conclusions The reaction of Me₃SiI with 1,4-dioxane gives 1,2-diiodoethane, 1,2-bis(trimethylsiloxy)ethane, and hexamethyldisiloxane, while reaction with 1,3,5-trioxane and 2,4,6-trimethyl-1,3-5-trioxane respectively gives the,-diiodomethyl and ethyl ethers and HMDS.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1391–1392, June, 1981.     

Research of Nanostructured Carbon Felt Materials as Electrodes of Vanadium Flow Batteries

Russian Journal of Electrochemistry - Flowing vanadium batteries are gaining great popularity in the world and are already ahead of lead-acid batteries in terms of installed capacity, but are far...