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Abstract: The compressibility of composite materials obtained by impregnation with water dispersion of polyurethane webs made of polyethylene terephthalate fibers with a diameter of 20 μm and a mixture of these fibers with polyethylene terephthalate fibers with a diameter of 42 μm is investigated. The influence of the composition on the formation of the structure of canvases and composite materials based on them is shown. In the process of heat treatment, the volume of webs made of fibers with a diameter of 20 μm increases and decreases for webs based on a mixture of fibers of different diameters. Compared with canvases with a degree of impregnation less than 1.0, the water permeability of materials of various compositions increases by 1.5–2.0 times. A model is proposed to predict the degree of compressibility of composite materials from the degree of impregnation and load. It is established that the compressibility of composite materials decreases when using a web as a fibrous filler in which the fibers are oriented perpendicular to the surface of the web. Less effective for reducing compressibility is the use of a web made of a mixture of fibers of different diameters as a fibrous filler.

The main objectives of this paper are to give an interdisciplinary overview of the current status of the research on planetary defense against asteroids, which is a real challenge, and consider technical proposals on the development of a multilevel planetary defense system based on modern space technologies, providing for the application of projectile asteroids to deflect target asteroids’ trajectories and distributed integrated navigation systems, the navigation equipment of which is supposed to be installed on many different objects. The composition of such navigation systems and their accuracies are discussed. This work is based on the results obtained by the international Research Laboratory of Space Research, Technologies, Systems and Processes [1], founded at Moscow Institute of Electronics and Mathematics (MIEM), Branch of Higher School of Economics (HSE) in 2011. The project was supported by the grant of the Government of the Russian Federation (2011–2013) [2, 3]. We have also used pioneering ideas from the course of lectures Models of planetary defense[4], prepared at the Department of Mechanics and Mathematical Modeling, MIEM NRU HSE in 2014 [4].

Abstract: A self-oscillatory structure based on the SiGe technology is proposed for generation of dynamic chaos in the microwave range. A circuit dynamic model of this system taking into account the characteristics and constraints of applied active and passive elements and the circuit topology in a crystal is created. Dynamic regimes of the structure are studied; the existence of chaotic regimes is demonstrated, parameter domains corresponding to these regimes are determined. An SiGe crystal for a monolithic integrated chip realizing the proposed self-oscillatory structure according to the 0.25-μm technology is developed and manufactured. Chip operation regimes are studied, stable generation of ultrawideband chaotic oscillations in a range of 3–8 GHz is obtained.

Abstract: An actively advancing branch of wireless ultrawideband communications is considered. Direct chaotic transceivers of two types are described. The transceivers were developed at the Institute of Radio Engineering and Electronics, Russian Academy of Sciences. Application of these transceivers in wireless sensor networks is demonstrated.

Abstract: A model of a chaos generator with a field-effect transistor as an active element is proposed. The generator is a variant of a Colpitts oscillator. A mathematical model described by three ordinary differential equations and a circuitry model taking into account the internal structure of the transistor and temperature and frequency effects are studied. Bifurcation phenomena, including transitions to chaos, are analyzed. Scaling relations that make it possible to scale the frequency band of chaotic generation and to use transistors with different steepnesses of the current-voltage characteristic are derived.

Abstract: A microwave-band chaos generator based on a bipolar transistor is proposed. A mathematical model of this generator that comprises a self-oscillating system with 2.5 degrees of freedom is considered. The dynamics of the generator is analyzed via the Advanced Design System (ADS) with the parameters of a real transistor, and the generator is simulated with allowance for the properties of the substrate. The results of the ADS-based simulation are compared with experimental data. It is demonstrated that application of the ADS simulation package for the analysis of the generator with regard to the effect of the board topology and the characteristics of the prototype materials makes it possible to reach a qualitative agreement between the numerical and experimental results.

Abstract??Digital simulation methods (ADS package) and an experimental model are used to demonstrate that a train of chaotic radio pulses may be generated under the effect of a chaotic periodic signal on a nonlinear dynamic system generating chaotic oscillations in the range 300?600 MHz. The system?s modulation characteristics are studied.

Irradiation of a planar structure made of periodically spaced gold V antennas by a femtosecond pulsed laser has revealed several anomalously reflected and refracted waves, interpreted as diffraction maxima. Compression of the pulse spectrum in scattered light is observed. The degree of compression and wave polarisation are found to be determined by the scattering direction.

Abstract: An aluminium matrix and a phenolformaldehyde polymer were tested as base materials for multielement standards resistant to high neutron doses in activation analysis. Interlaboratory analyses showed that these standards can be certified for the concentrations of the majority of introduced elements.

Abstract: A special method of simultaneous serial INAA of about 18 elements in human whole blood samples has been developed. The frequency distribution of tracer contents in the blood of healthy people living in Georgia has been studied. The kinetic curves of age-dependent changes of various microelement contents in human blood over an interval from 15 to 110 years has been plotted.

Abstract: New synthetic standard samples (SSB-1 and SSB-2), produced on the basis of phenol-formaldehyde resin in the shape of tablets are suggested. The samples are intended for INAA of biological materials. SSB-1 and SSB-2 samples contain Se, Cr, Au, Sb, Ag, Rb, Fe, Zn, Co and Ca, Ba, Hg, Sn, Br, Cs, Ni, Sc and Na. The concentrations of these elements are chosen so that the maximum statistical error of gamma-quantum registration by the semiconductor detector should not exceed 3% when irradiating samples in a neutron flux of sim1013 n·cm–2·s–1.

Abstract: The photovoltaic effect in some crystals without a center of symmetry (ZnO, α-HgS, and α-quartz) is investigated. It is shown that the impurity centers of different nature give a different contribution to the photovoltaic effect. The influence of the optical recharging of the impurity centers on the spectral distribution and on the kinetics of the photovoltaic effect is noted. The optical activity strongly influences the angular dependence of the photovoltaic current, observed in the linearly polarized light.

1.Compounds with a quaternary N atoms are formed by the action of BP on amines, in particular TMPD.2.For the first time, the electronic absorption spectra of the cation-radicals of the DMA and DBA, which resulted from the action of the corresponding amines on BP, were ascertained.3.The stability of the cation-radicals of the amines depends on their acidic properties.

Abstract: A high level of antibodies to the glycoprotein fraction ofBac. megatherium H with a molecular weight of 8–10 kD is demonstrated in stomach cancer; in highly differentiated stomach cancer the level of antibodies to the glycoprotein with a molecular weight of 12–15 kD is also increased. The level of antibodies to the glycoprotein with a molecular weight of 10–12 kD is increased in peptic and duodenal ulcer. It is suggested that these glycoprotein fractions are useful for diagnosing oncological and nononcological diseases of the alimentary canal.