New carbazole-containing chalcones and pyrimidines based thereon: Synthesis and electrochemical study

Condensations of aromatic carbo- and heterocyclic ketones and aldehydes in methanol gave new chalcones containing carbazole fragments, 1,3-diaryl(9-R-9H-carbazol-3-yl)prop-2-en-1-ones. Some of the synthesized chalcones reacted with guanidine sulfate to produce 2-amino-4,6-diarylpyrimidines that are promising materials for the design of light emitting diodes. Study on electrochemical polymerization of both chalcones and pyrimidines derived therefrom showed that almost all the examined substrates give rise to stable colored conjugated polymer films on the surface of working electrode under conditions of cyclic voltammetry.     

Modeling learning process

We consider the problems of creating computer-based learning systems and teaching environments on the basis of discrete models based on automata. We estimate the perspectives of using computer models of learning for improving the quality of education.     

Magnetic and magnetoelastic properties of Fe64Co21B15 and Fe73Co12B15 amorphous metal strips

The effect of magnetic annealing on the magnetic and magnetoelastic properties of FeCoB amorphous metal strips in the temperature range from 290 to 380°C has been investigated. With the method of photostimulated exoelectronic emission it has been found that in this temperature range there occurs crystallization of the surface of the test strips. It has been shown that the minima of the coercive force, residual induction, and differential magnetic permeability and the maximum absolute values of the negative Δ-effect are attained at magnetic annealing temperatures close to the temperatures corresponding to the maxima of the intensity of photostimulated exoelectronic emission. An explanation of the results obtained has been proposed which is based on the notions about the effect of internal stresses on the induced magnetic anisotropy of the test strips. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 59–65, August, 2006.     

Two frequency light induced absorption and energy density of localized states in amorphous semiconductors

Infrared light induced absorption is proposed to determine the energy dependence of localized electrons' density in amorphous semiconductors. The possibility of the experimental test of energy independence of the recombination coefficients is shown.