The temperature dependences of the dielectric spectra of Ag2S nanocrystallites synthesized inside the channels of nanoporous glasses NPG-17 with an average diameter of filamentous pores of 17 nm are studied. The macroscopic mechanism for the occurrence of the frequency dependence of the electrical response of a nanoporous structure NPG-17 + Ag2S is proposed. Formation of the model of mechanism is based superionic phase transition in Ag2S nanocrystallites fixed inside the channels of nanoporous glass is discussed. Keywords: silver sulfide, Ag2S, nanoporous glasses, nanostructured materials, impedancemetry.

The hybridization of vanadium ions and oxygen ions is considered for four vanadium oxides included in the Magneli series: VO, V2O3, VO2, V2O5. Based on the data on hybridization, the details of the structure of the crystal lattice of these oxides are analyzed. For each oxide, the role of electrons not participating in the stabilization of the crystal frame in the process of the semiconductor-metal phase transition was revealed. The complex Mott-Peierls character of the phase transitions in all the listed strongly correlated compounds has been established. It is shown that as the degree of oxidation of the V atom increases, the numerical value of the metallic conductivity of the high-temperature phase naturally decreases and, simultaneously, the temperature of the phase transition from the semiconductor to the metallic state increases. Keywords: phase transitions, Magneli series, electron correlations, hybridization of atomic orbitals.

A method of transcranial electromagnetic stimulation of the mammalian brain is proposed. The method is based on the interference of currents caused by high-frequency orthogonal oscillations of electric fields, which are modulated by low-frequency meander pulses. The effectiveness of the method was confirmed by the results of experiments on stimulating the brain of rats and rabbits. Keywords: electromagnetic stimulation, interference, alpha-rhythms, theta-rhythms, serotonin, beta-endorphins, neuron.

The spectra of the refractive index n(λ) and the extinction coefficient k(λ) of thin VO2, VO2 : Mg, VO2 : Ge films were measured using the ellipsometric method. For an undoped VO2 film at a wavelength λ=632.8 nm, near the insulator-metal phase transition, the n(T) and k(T) thermal hysteresis loops were studied. An interpretation of the results is given on the base of the Moss relation, the idea of a change in n(T) and k(T) with an impurity variation of the material density, and also on the base of the ideology of the Coulomb transformation of the density of states function in strongly correlated materials. Keywords: ellipsometry, vanadium dioxide, insulator-metal phase transition, strongly correlated materials.

A comparative analysis of the electrically conductive properties of strongly correlated oxides: vanadium oxide VO and vanadium pentoxide V2O5, belonging to opposite ends of the Magneli series, is carried out. It is shown that, despite the radical difference in the symmetry of the crystal lattices of these compounds, these materials have a number of fundamental common properties, the main of which are the dependence of the width of the energy gap (gap band) on the occupation of the conduction band by electrons and the occurrence in both compounds of an electronic Mott transition extended in temperature. It is shown that vanadium pentoxide is a classic Mott insulator. Keywords: vanadium oxides, phase transition, electronic correlations.