A calculation technique based on the Dipole Electron Shifting model is applied to investigate the nonlinear optical properties of the crystals of langasite family. The d11 component of nonlinear optical susceptibility tensors is determined for La3Ga5SiO14, Ca3Ga2Ge4O14, La3Ga5.5Ta0.5O14 La3Ga5.5Nb0.5O14 crystals. The results of the calculations are compared with the experimental ones, described in literature.

The present paper presents an investigation of the current states in a double barrier tunnel Josephson junction. The Josephson supercurrent in tunnel multilayered structures has signicant features related to the phenomenon of quantum resonant tunneling. The value of the supercurrent is very sensitive to the distance between the barriers (thickness of interior superconductor layer). This gives a possibility to fabricate the tunnel Josephson junctions with hight values of critical supercurrent. In this paper the relationship for the thickness of an interior superconductor layer has been found for which the double-barrier becomes fully transparent. We also investigated the currentphase relation for the double barrier tunnel Josephson junction, derived the equation for the critical value of a supercurrent and calculated the skewness in the currentphase relation for dierent values of the transparency of the junction.

The papers presents the results of the theoretical calculations of the partial and total density of states of LaF3:Sm and LaF3:Pm crystals. We analyze the positions of 4f and 5d energy states of activator ions in the energy structure of the host material. We calculated and described electronic energy band structures of the above mentioned crystals. We made a quantitative and qualitative comparison between the energy structure of LaF3:Sm and LaF3:Pm crystals.

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Film polymer composite scintillators based on scintillation polystyrene with n-terphenyl and POPOP activators and loaded LaF3 nanoparticles have been developed for the registration of ionizing radiation.LaF3 nanoparticles were obtained through precipitation involving ion substitution from LaCl3 water and water-alcohol solution with the addition of NH4F solution.The spectral and kinetic properties of polymer nanocomposites under X-ray irradiation have been studied.It was found that the eciency of the ionizing radiation detection for a polystyrene composite with loaded non-luminescence LaF3 nanoparticles increases by an order of magnitude compared to the eciency of a polystyrene scintillator without nanoparticles, maintaining the spectral composition of the polystyrene scintillator radiation and its speed was 3 ns.It is proposed that the main mechanism of the scintillation generation is the excitation of polystyrene matrix by electrons that escape from the nanoparticle by the mechanism of photoeect under the inuence of ionizing radiation.