Vol 71, No 2 (2016)

Human-scaled (in complexity) systems possess a unique feature, viz., the continuous random motion of many components of the state vector x = x(t) of such living systems. Taking this property into consideration causes the rejection of any of the known types of stationary modes (e.g., dx/dt = 0) and requires revision of the concept of chaos. A new approach to the understanding of living systems (as a third paradigm of the natural sciences) and new methods for the study of living systems (as a theory of chaos and self-organization) are proposed. Common grounds of physics and theory of chaos and self-organization are revealed as a generalized uncertainty principle and a limit on the parameters of quasi-attractors.

The equations of the electromagnetic field in a solid with defects were obtained and an approximate wave solution was found by the Debye–Rytov method.

Vacuum polarization is considered in a model that takes the anomalous magnetic moment (AMM) of Dirac fermions in a uniform magnetic field in the presence of an additional axial-vector interaction into account. Corrections to the effective Lagrangian of the model that are quadratic with respect to the AMM and axial-vector interaction in different configurations of the given model parameters are calculated.

This paper discusses possible methods for the synthesis of informative features for the classification of signal sources in cognitive radio systems using artificial neural networks. A synthesis method based on the use of autoassociative neural networks is proposed. From the point of view of the classification of the signals, informativeness of synthesized features is estimated using a modified artificial neural network based on radial basis functions that contains an additional self-organizing layer of neurons that provide the automatic selection of the variance of basis functions and a significant reduction of the network dimension. It is shown that the use of autoassociative networks in the problem of the classification of signal sources makes it possible to synthesize the feature space with a minimum dimension while maintaining separation properties.

The peculiarities of nuclear-resonance reflectometry (NRR) for different types of magnetic ordering in multilayers are considered. The theory of NRR for noncollinear magnetic structures is briefly presented. Model calculations are carried out for the [⁵⁷Fe(8Å)/Cr(20 Å)]₃₀ structure, in which the magnetization varies with depth in different ways. The results show that the “magnetic” maximum on the NRR curve occurs only when the directions of the hyperfine fields in adjacent iron layers have different projections on the synchronous beam direction. Spiral alignment of the multilayer magnetization causes the emergence of satellites near the Bragg maximum, while the “magnetic” maximum does not occur. With more complicated magnetic ordering profiles the characteristic features of available experimental curves can be explained.

Iron and iron–cobalt nanostructures that were synthesized in polymer ion-track membranes have been studied via Mössbauer spectroscopy combined with raster electron microscopy, energy-dispersion analysis, and X-ray diffraction data. The obtained nanostructures are single-phase bcc Fe_1–xCo_x nanotubes with a high degree of polycrystallinity, whose length is 12 μm; their diameter is 110 ± 3 nm and the wall thickness is 21 ± 2 nm. Fe²⁺ and Fe³⁺ cations were detected in the nanotubes, which belong to iron salts that were used and formed in the electrochemical deposition. The Fe nanotubes exhibit eventual magnetic moment direction distributions of Fe atoms, whereas Fe/Co nanotubes have a partial magnetic structure along the nanotube axis with a mean value of the angle between the magnetic moment and nanotube axis of 34° ± 2°. Substituting the Fe atom with Co in the nearest environment of the Fe atom within the Fe/Co structure of nanotubes leads to a noticeable increase in the hyperfine magnetic field at the ⁵⁷Fe nuclei (by 8.7 ± 0.4 kOe) and to a slight decrease in the shift of the Mössbauer line (by 0.005 ± 0.004 mm/s).

In this work we describe a method for evaluating such parameters of an interfacial layer as the refractive index and thickness of the liquid–vapor interface, based on the measured ellipticity coefficient, ρ, at different wavelengths of the probing light and the data [1] for several pure fluids. In particular, the change in the main angle of incidence was evaluated in the “layer on the substrate” structure. The surface layer is assumed to be homogeneous.