Photostability and fluorescence parameters of porphyrinoids: The effect of the macrocycle structure and the medium

The effects of the macrocycle structure and the medium nature on photodecomposition of porphyrinoids under UV irradiation have been studied. The influence of protonation, nonplanar structure of the molecule, and reactivity of NH bonds on the photostability of porphyrins and their analogs has been shown.     

Correction to: Aziridine-2-Carboxylic Acid Derivatives and Its Open-Ring Isomers as a Novel PDIA1 Inhibitors

Chemistry of Heterocyclic Compounds -     

Calculation and comparative analysis of IR spectra of (22S,23S)-24-epibrassinolide and (22S,23S)-28-homobrassinolide

A consistent calculation of frequencies and intensities of normal vibrations of some steroid phytohormones having biological activity ( (22S,23S)-24-epibrassinolide and (22S,23S)-28-homobrassinolide molecules) is performed within an original approach combining a classical normal mode vibration analysis by the molecular mechanics method and a quantum chemical estimation of absolute intensities. Based on a comparison of the experimental and theoretical spectral absorption curves the interpretation of IR spectral absorption bands is given for the first time and the effect of structural differences within the side chain of these molecules on the formation of their IR spectra in the range 1500-950 cm^?1 is estimated.     

Preparation and Properties of Some Poly-aluminum Organosiloxanes with Cyclonetwork Structures

Abstract

Poly condensation of aluminum butoxide with α, ω -dihydroxydi-methylsiloxanes having varied polymerization coefficients has been studied. Some kinetic dependencies in the generation of cyclonetwork poly(aluminum dim ethylsiloxanes) have been investigated and the rate constants of cross-linking reaction, depending on the chain length of initial α, ω-dihydroxypolydimethylsiloxanes, have been calculated.     

Methods for Increasing the Spatial Resolution of a Distributed Beam-Loss Monitor Based on Cherenkov Radiation in an Optical Fiber

Physics of Particles and Nuclei Letters - Abstract—The principle of operation of a distributed beam-loss monitor based on the Cherenkov radiation in optical fiber is considered. The monitor...     

Asymptotic analysis of perforated plates and membranes. Part 2: Static and dynamic problems for large holes

Static and dynamic problems for the elastic plates and membranes periodically perforated by holes of different shapes are solved using the combination of the singular perturbation technique and the multi-scale asymptotic homogenization method. The problems of bending and vibration of perforated plates are considered. Using the asymptotic homogenization method the original boundary-value problems are reduced to the combination of two types of problems. First one is a recurrent system of unit cell problems with the conditions of periodic continuation. And the second problem is a homogenized boundary-value problem for the entire domain, characterized by the constant effective coefficients obtained from the solution of the unit cell problems. In the present paper the perforated plates with large holes are considered, and the singular perturbation method is used to solve the pertinent unit cell problems. Matching of limiting solutions for small and large holes using the two-point Padé approximants is also accomplished, and the analytical expressions for the effective stiffnesses of perforated plates with holes of arbitrary sizes are obtained.     

Analytical study of the interface in fibre-reinforced 2D composite material

Imperfect bonding between the constitutive components can greatly affect the properties of the composite structures.An asymptotic analysis of different types of imperfect interfaces arising in the problem of 2D fibrereinforced composite materials are proposed.The performed study is based on the asymptotic reduction of the governing biharmonic problem into two harmonic problems.All solutions are obtained in a closed analytical form.The obtained results can be used for the calculation of pull-out and pushout tests,as well as for the investigation of the fracture of composite materials.