Introduction of magnetic nanoparticles into composite sorbents based on polymer matrices has received great attention due to the possibility of using cheap iron oxides and removing spent sorbents by means of magnetic separation. In the present paper, we discuss the problem of creating magnetic sorbents using two types of matrices as host materials: synthetic cation exchange resin and natural aminopolysaccharide chitosan. The possibilities of applying matrices for the in situ formation of oxide phases of a specified composition with the required content of an inorganic component in a composite material were estimated. The composition of the oxide phase formed in the composite material was studied, and particle sizes were evaluated by the method of X-ray diffraction analysis. Magnetic characteristics were investigated. Sorption characteristics with respect to strontium for the composites containing iron oxides were determined.

The paper presents the results of studies of the resonance structures of the background electromagnetic noise spectrum obtained in a series of experiments in the autumn of 2012 in Karelia. The experiments are unique because the background noise was detected at stations spaced by a distance much less than the doubled effective waveguide height (about 50 km) in a region close to the main ionospheric trough, the structure and position of which were determined based on radiotomographic data. It is shown that the dimensions of the ionospheric local region, which affects both the generation of spectral resonance structures in particular and the propagation of electromagnetic waves in the considered range in general, depend significantly on the variation of ionospheric parameters in regions with strong horizontal inhomogeneity.

The results of measurements of the artificial electromagnetic signal in the range 0.1–10 Hz on the Spitsbergen archipelago are presented in this paper. The signal was emitted by a horizontal antenna located on the Kola Peninsula. Resonance spectra structures (RSSs) caused by the influence of the ionospheric Alfvén resonator (IAR) were found in the artificial signal. The calculations of the field performed using the method of a two-dimensional telegraph equation for an anisotropic inhomogeneous model of the ionosphere allowed us to explain the main properties of the observed artificial RSS signal. Special attention was focused on the choice of the ionospheric model and calculation of the reflection coefficient for a plane wave normally incident on the ionosphere. The needed profiles of the ionospheric parameters were selected on the basis of the Upper Atmosphere Model (UAM) and IRI2007 model, while the atmospheric parameters were specified on the basis of MSIS-E-90. The advantages of the UAM model compared with the IRI for the description of the experimental results in a high-latitude region are shown in the paper.

The nonlinear susceptibility and the degree of invariance for inversion 1 η [ϕ( r r )] (pseudosymmetry) of electrical potential function of atomic structure were discovered for Ba0.25Sr0.75Nb2O6, Ba0.39Sr0.61Nb2O6, Ba0.5Sr0.5Nb2O6, and Ba0.39Sr0.61Nb2O6 + 0.05 CeO2 crystals. It is shown that if 1 η [ϕ( r r )] is close to unity, the nonlinear susceptibility of such crystals decreases with the increase in the degree of invariance of the electric potential.