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The results of numerical study of relaxation processes in oxygen at high temperatures are presented. Collisions of particles (atoms and molecules) are described by the molecular dynamics methods based on trajectory calculations within the framework of classical mechanics. A complex of programs for calculating the relaxation processes in mixtures of high-temperature gases involving internal modes that describe rotational and vibrational motions in molecules and molecular dissociation and atomic recombination in the presence of a third body is described. The relaxation process is described with reference to variation in the parameters in a mixture of atomic and molecular oxygen with various initial temperatures of the translational and internal modes. The results of calculations of the structure of shock wave in oxygen with the maximum translational temperature on the front higher than 5000–11 000 K are given. The results obtained are compared with experimental data.

Abstract—New KIZ infrasound stations (ISs) have been produced by the Typhoon Research and Production Association (Obninsk, Russia) and operated offline over several years at several locations in Russia. All the IS components, i.e., the configuration, microbarometers, pipe arrays, the data acquisition system, the hardware box, and other parts have been developed on the basis of the experience gained in designing and operating similar systems and, primarily, the infrasound component of the International Monitoring System for monitoring nuclear test explosions. In addition to the high and stable metrological characteristics, the main advantages of these ISs are their comparatively low cost, minimum operating expenses, reliable performance in a wide range of weather conditions, and easy metrological adjustment and calibration. The KIZ ISs are adapted to the operating conditions on a territory of a typical RF weather station.

The Marchuk model of infectious diseases is considered. Distributed control to make convergence to stationary point faster is proposed. Medically, this means that treatment time can be essentially reduced. Decreasing the concentration of antigen, this control facilitates the patient’s condition and gives a certain new idea of treating the disease. Our approach involves the analysis of integro-differential equations. The idea of reducing the system of integro-differential equations to a system of ordinary differential equations is used. The final results are given in the form of simple inequalities on the parameters. The results of numerical calculations of simulation models and data comparison in the case of using distributive control and in its absence are given.

Abstract—A new class of nonreactive memristor generators is considered. It is shown that the double memristor generator has wide functionality for controlling and modulating output signals. The various operation modes of such generators are studied, including those characteristic of artificial neurons nodes, such as excitation and inhibition, control of pulse trains, and change in the repetition rate in a packet.

AbstractThe memristor pulse series oscillator based on the Schmitt trigger with a memristor and a capacitor at the input is discussed. It is shown that such circuit provides the generation of a pulse series the duration of which is determined by the amplitude of the input signal. The simulation results corroborate the wide functionality of the oscillator under discussion.

The aspects of design of reactance-less oscillators based on memristors are considered. The requirements on load elements in the circuits of such oscillators are formulated. The equations describing the dynamical behavioral of the memristor oscillators with the use of linear-drift models are presented. Examples of the analysis and synthesis of oscillators using such equations are presented. The possibility of generation in the circuits under consideration of periodic signals with a waveform close to harmonic oscillations is shown.

The method of temperature coefficients along with detail digital maps and GIS-technologies were used to develop a model of spring snow melting, which takes into account the high-accuracy spatial distribution of meteorological data, relief features, and soil-vegetation cover. The effect of slope aspect on the processes of spring snow melting was evaluated with the use of correction coefficients, and a procedure for determining their optimal values was developed. A method was proposed for verification and validation of the calculated spatial distribution of snow cover with the use of space monitoring data.

In this paper, we present a numerical solution of the discrete control problem for the immune response in an infectious disease under conditions of uncertainty. This problem is described by a nonlinear system of ordinary differential equation with delay. Conditions of uncertainty mean that values of the parameters of the model are unknown and their estimates are corrected by new experimental data. We propose an algorithm that allows one, within the framework of the mathematical model of an infectious disease, to construct the control and to identify parameters. By using the algorithm proposed, we develop treatment programs based on immunotherapy. We show that immunotherapy is an effective treatment for all main forms of disease: acute, chronic, and lethal.

The existing ideas on the status of the Navier–Stokes equations are changed in taking into account the following facts: generally speaking, the terms of these equations neglected in the boundary layer equations are of the order of certain Burnett terms in the conservation equations; the Navier–Stokes equations cannot be used to describe slow nonisothermal gas flows since in this case it is necessary to take the Burnett temperature stresses into account; and in the transport relations the Burnett terms determine certain effects (for example, the mechanocaloric effect).

The article presents the results of evaluating the applicability of various types of iron-containing nanoparticles in magnetic hyperthermia, as well as determining the degradation resistance of nanoparticles. The objects of study were iron-containing nanoparticles obtained by chemical precipitation and subsequent modification with gold, gadolinium, and neodymium. The main methods for studying the properties of the synthesized nanoparticles were transmission electron microscopy, X-ray phase analysis, and Mössbauer spectroscopy. Evaluation of the efficiency of the use of the synthesized nanoparticles in magnetic hyperthermia showed that Fe3O4@GdFeO3 nanoparticles, for which the specific absorption rate was more than 120 W/g, have the highest efficiency. An assessment of the resistance of the synthesized nanoparticles to corrosion in water at different temperatures showed that Fe2O3@NdFeO3 and Fe3O4@GdFeO3 nanoparticles have the highest resistance to degradation. It has been established that in the case of the initial Fe3O4 nanoparticles, the degradation processes are accompanied by partial destruction of the particles, followed by amorphization and destruction, while for Fe2O3@NdFeO3 and Fe3O4@GdFeO3 nanoparticles, the degradation processes proceed much more slowly, due to the presence of interfacial boundaries, which slow down the corrosion processes. The obtained results of corrosion tests in aqueous media make it possible to predict the area and time frame of applicability of iron-containing nanoparticles when using them in the biomedical direction, as well as to determine storage conditions.