On approximation properties of a family of linear operators at critical value of parameter

We introduce the family of linear operators

associated to a certain “admissible bunch” of operators S_t, t>0, acting on , and investigate the approximation properties of this family as α→0⁺. We give some applications to the Riesz and the Bessel potentials generated by the ordinary (Euclidean) and generalized translations.     

Global existence and nonexistence results for a class of semilinear hyperbolic systems

In this paper, we investigate the Cauchy problem for a class of the system of semilinear hyperbolic equations with damping. With the use of the L_p → L_q type estimation for the corresponding linear problem and the method of comparison of functional, the existence and nonexistence criteria of global solutions are found. Copyright © 2012 John Wiley & Sons, Ltd.     

Probing little Higgs model in e<Superscript>+</Superscript>e<Superscript>-</Superscript>→νν̄γ process

We study the process e⁺e^-→νν̄γ to search for its sensitivity to the extra gauge bosons Z₂, Z₃ and W₂ ^±, which are suggested by the little Higgs models. We find that the ILC with and CLIC with cover different regions of the LHM parameters. We show that this channel can provide a determination of the parameters, complementary to measurements of the extra gauge bosons obtainable at the upcoming LHC experiments. PACS 14.80.Cp; 12.60.Fr; 12.60.Cn     

Composition and properties of the reaction products of p-cresol with camphene

Russian Chemical Bulletin - The products of the reaction between p-cresol and camphene were isolated and characterized. Their antiradical activity and toxicity were studied. The pharmacological...     

Optical Properties of the SiOx (x < 2) Thin Films Obtained by Hydrogen Plasma Processing of Thermal Silicon Dioxide

Optics and Spectroscopy - The optical properties and composition of thermal silicon oxide thin films processed in a hydrogen electron cyclotron resonance plasma have been studied by ellipsometry,...     

Bis(4″-nitro-[3,3’:4’,3″]terfurazan-4-yl)diazene as a new energetic compound

Russian Chemical Bulletin - 3,4-Bis(4-aminofurazan-3-yl)furazan was used to obtain a new energetic terfurazan derivative, namely,...     

Noncovalent Interactions of π Systems with Sulfur: The Atomic Chameleon of Molecular Recognition

The relative strength of noncovalent interactions between a thioether sulfur atom and various π systems in designed top pan molecular balances was determined by NMR spectroscopy. Compared to its oxygen counterpart, the sulfur atom displays a remarkable ability to interact with almost equal facility over the entire range of π systems studied, with the simple alkene emerging as the most powerful partner. With the exception of the O???heteroarene interaction, all noncovalent interactions of sulfur with π systems are favoured over oxygen.     

Structural analysis of bioactive glasses

In this study four series of single and mixed alkali glass systems were made and investigated using MAS NMR. Additionally the densities of the glasses were measured experimentally, as well as calculated theoretically using Doweidar’s model. MAS NMR was used to obtain a quantitative structural understanding of glasses by calculating the concentrations of bridging and non-bridging oxygens per silicon oxygen tetrahedron as a function of the alkali oxide concentration expressed as Qⁿ. ²⁹Si MAS NMR spectra exhibited a single resonance corresponding closely with Si in a Q² state. The chemical shift of the ³¹P MAS NMR peak was attributed to phosphate in an orthophosphate environment. The ²⁹Si NMR spectra are in agreement with the density data. Using Doweidar’s model the proportions of Q² and Q³ were calculated, showing that all glasses studied are predominantly Q² in structure, i.e. silica chains which readily dissolve. The changes in the chemical shifts of the Q² and Q³ species with composition have been interpreted as resulting from the preferential association of Na⁺ with Q³ and Ca²⁺ with Q².     

Five-membered 2,3-dioxo heterocycles: LXII. Reaction of 3-aroyl-1H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones with N,N′-dihydroxycyclohexane-1,2-diamine. Unusual rearrangement in the spiro[quinoxaline-2,2′-pyrrole] system

3-Aroyl-1H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones reacted with N,N′-dihydroxycyclohexane-1,2-diamine to give 3-aroyl-1′,4,4′-trihydroxy-1-(2-hydroxyphenyl)-4a′,5′,6′,7′,8′,8a′-hexahydro-1′H-spiro[pyrrole-2,2′-quinoxaline]-3′,5(1H,4′H)-diones which underwent rearrangement into 1′-aroyloxy-4,4′-dihydroxy-1-(2-hydroxyphenyl)-4a′,5′,6′,7′,8′,8a′-hexahydro-1′H-spiro[pyrrolidine-2,2′-quinoxaline]3′,4,5(4′H)-triones via [1,4]-migration of the aroyl group. The product structure was proved by X-ray analysis.