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A structural-phenomenological concept (SPhC) of monitoring the residual strength of composite materials is proposed. SFK was developed taking into account the kinetics of damage and destruction of polymer composite material (PCM) at the micro-, meso- and macroscale levels, which generate acoustic emission pulses (AE) recorded by the receiving transducers of the antenna array. A correspondence between the ongoing destruction of the composite material structure at the micro-, meso- and macroscale level and the AE pulses recorded at the same time and their weight content provides the possibility of monitoring of the damage kinetics in the loading mode at all structural levels, and, consequently, the possibility of control of the residual strength of the product. An algorithm and software have been developed that made it possible to divide the recorded AE signals into the clusters of lower, middle and upper energy levels corresponding to micro-, meso- and macroscale disruptions of the structure of a composite material, calculate the AE activity and the weight content of location pulses in energy clusters, thus displaying the dynamics of their changes every second. Comparison of the current values of the most informative parameters of the weight content of location pulses in energy clusters with the threshold values recorded during the destruction of the material provides monitoring of the residual strength of the product in the loading mode. The validity of the developed concept, algorithm and software was proved during tests of elementary and structurally similar samples of PCM under different loading conditions. An example of using the developed technique for revealing the areas of the most intense damage accumulation in a MS-21 fuselage panel at a stepwise increase in the compressive load is presented. In addition to the possibility of identification of the area of intensive accumulation of damage and failure of the structure of the composite material, SPhC of the AE diagnostics provides also the possibility of tracing the damage kinetics at different scale-structural levels, controlling the level of the residual strength of the panel upon the stepwise compression.

The authors have presented new data on the parameters of combustion and detonation of biofuel mixtures of carbon oxide and hydrogen (synthesis gas) with oxygen and air with variation of the ratio between CO and H2 and between the fuel components and the oxidant alike, including data on the critical energies of initiation of detonation, the characteristic dimensions of detonation cells, velocities of detonation, and energy release in detonation waves.

1H NMR in quasi-one-dimensional spin chains is investigated experimentally on the single crystal of hambergite, Be2BO3OH. The orientations at which the change of the spin chain direction with respect to the external magnetic field results in the occurrence of homogeneous and alternating chains are found. The dependence of the lineshape on the orientation in magnetic field for alternating spin chain is obtained and the data are analyzed using a simple model taking into the dipolar interactions with the nearest neighbors. The analogies with the lineshapes typical for spin systems with a small number of spin and known linear spin chain are discussed.

Textured samples of the Bi19Gd0.1Te3, which is a thermoelectric material characterized by the formation of a lamellar grain structure, were prepared using spark plasma sintering. Lamellar layers consist of grains elongated in the plane parallel to the direction of the application of pressure during sintering. The properties of the samples measured in the direction perpendicular to the application of pressure correspond to microgranular structures, and those in the perpendicular direction to nanograined structures, which gradually transfer into microgranular structures with increasing sintering temperature. With a decrease in the grain size, the electrical resistance gradually increases, and the total thermal conductivity decreases, and these tendencies are most clearly manifested in the transition from micrograined to nanograined structures. The observed size effects are due to the scattering of electrons and phonons at grain boundaries.

We consider the nature of the phenomenon of acoustic emission (AE) occurring in the process of deformation and destruction of solid bodies. A theoretical analysis of the processes of transformation and dissipation of energy during the destruction of structural bonds of an idealized model of a solid has been carried out. Using A-line32D and PCI-2 AE systems, Onyx vibration analyzer, and Videosprint high-speed camera, as well as numerical simulation in the LS-DYNA software environment, we study wave processes occurring during deformation and rupture of reinforcing fibers of composite materials. The obtained experimental and calculation data indicate that the main energy is emitted within the period of the aftereffect of fiber rupture in the range of sound frequencies less than 2 kHz. In this case, the energy of the peak values recorded in the ultrasonic frequency range does not exceed several percent of the maximum level at the carrier frequency in the audio range.

Specificities of the theory of deformation interactions in polycrystalline alloys are discussed in this work. It is shown that, in the continuous approximation, these interactions are completely determined by the dilatation components of elastic and inelastic strain fields created by the systems of grain boundaries and the system of impurity atoms. Formulas and estimates for various types of deformation interactions are presented. Problems concerning the effect of the boundaries on the lattice parameters, the concentration expansion of the lattices of inhomogeneous alloys, and the interaction of grain boundaries are discussed.

In order to identify the evolutionary stages of the natural environment of the Western Caspian Sea region in the second half of the Holocene, buried submound soils and bone remains in the Bogomolnye Peski 1 mound were analyzed. Spore-pollen, anthropological, and isotope analyzes were carried out on soil and bone samples. Bioclimatic fluctuations of the natural environment were established based on the reconstruction of paleolandscapes (soils, vegetation) and associated changes in socio-cultural factors (changes in paleo-diet, anthropological characteristics).

Ethylene/1-hexene copolymerization was carried out with a new Ti (IV) complexes stabilized by fluorinated 2-hydroxymethylphenol derivatives and activated by MAO-free binary cocatalysts—{alkyl aluminum chloride + Bu2Mg}. Structures and properties of the obtained copolymers were measured by DSC, GPC and 13C NMR. The effects of the ligand structure and the nature of organoaluminum activator on the polymer yield, comonomer incorporation, polymer composition, molecular weight, polydispersity index and stress–strain behavior have been investigated. The results indicated that the complex with adamantyl substituent was the most active in this series. The obtained copolymer exhibited the highest 1-hexene incorporation content of 18.9 mol%

Spark plasma sintering (SPS) was applied to prepare textured Bi1.9Gd0.1Te3 compounds with various grain structures, tuned by changing in the sintering temperature. The grains forming ordered lamellar structure under texturing are elongated in plane oriented perpendicularly to SPS-pressing direction. As result, average grain size measured parallel to this direction and corresponding to fine-grained samples happened to be much less as compared to relevant size for perpendicular direction characteristic for coarse-grained samples. Anisotropy in electrical resistivity inherent for single crystal was found to be partially recovered in textured samples, i.e. resistivity measured along directions parallel or perpendicular to SPS-pressuring direction is different. Moreover, resistivity for both directions is increasing with decreasing in grain size or with decreasing in intergrain distance. Grain size effect on resistivity due to grain boundary scattering of electrons was found to be anisotropic, since the effect is observed for different ranges of change in average grain sizes.

Using the experimental setup for poling film samples with capability of continuous monitoring of generation signal of second harmonic, the conditions of effective orientation of chromophore molecules based on polyfluoro-substituted triaryl pyrazoline and dicyan-substituted isophoron in micron films of polycarbonate are determined. The second harmonic is excited with the pulse Nd:YAG laser with 1064 nm when chromophore molecules are oriented in the field of corona discharge. The dependences of signal level of the second harmonic on the potential at field mesh and on the potential at needle electrode are measured.

A computational algorithm is presented for determining the modes of thermoelectric cooling that ensure the given temperature difference of the base of the heat-loaded element and the environment. The obtained analytical expressions make it possible to determine the power supply current of the thermoelectric module taking into account its operating characteristics, thermal resistance of the cooling system, and power of the heat-loaded element. The dependences of the current strength on the value of the given temperature difference are calculated and the parameters affecting the thermoelectric cooling modes are analyzed.

Many-spin entanglement is investigated in one-dimensional zigzag chains, consisting of up to 12 spins 1/2, with nearest neighbor and next nearest neighbor interactions at high and low temperatures. We consider multiple quantum (MQ) nuclear magnetic resonance (NMR) dynamics. The second moment of the distribution of MQ coherences, which provides a lower bound on the quantum Fisher information, is calculated for different temperatures and evolution times. The dependence of the number of the entangled spins on the temperature and the chain length is obtained.

The effect of deforming cutting (DC) on structural and phase transformations in iron and steels 35 and U8 is studied with the help of scanning optical and transmission electron microscopy. It is shown that with an increase in carbon content test material structure and phase composition become more complex.

A mathematical model is proposed for determining the quality of applying a heat-conducting compound, and simulation results are presented. The model is based on the theory of heat transfer in a solid. The model has been verified using experimental data obtained by measuring the temperature at the points of contact of two bodies using thermocouples. It is shown that the data obtained using thermocouples coincide with the data obtained using thermopower.

Matrix photosensitive elements based on a HgCdTe semiconductor solid solution on silicon substrates with 640 × 512 elements at a pitch of 25 μm with a long-wavelength sensitivity of 5 μm at half maximum are designed and produced. The scheme and topology are developed according to which matrix multiplexers with 640 × 512 elements at a pitch of 25 μm, which ensure operating modes at a clock frequency up to 10 MHz, are manufactured. Using a hybrid assembly method on indium bumps, a matrix photodetector with 640 × 512 elements at a pitch of 25 μm is produced. The best photodetector specimens are characterized by the following parameters: average NETD value 99.5%.

The modern designs of magnetic field transducers (MFTs) based on nanostructures with the spin-tunnel magnetoresistive effect (STMR) and the main areas of their application are considered. The results of an experimental study of two constructive versions of magnetic field transducers with an even and odd output characteristic are presented. The sensitivity of the fabricated MFT model based on the STMR effect with an even output characteristic is 0.54 mV/(V Oe) in the range of a magnetic field with the intensity ranging from 0 to 40 Oe. The results of dependency conversion are presented. R(H) nanostructures with the STMR effect by thermomagnetic treatment to reduce hysteresis and increase linearity in the working range of the magnetic field. The sensitivity of the fabricated MFT model based on the STMR effect with an odd output characteristic is 5.4 mV/(V Oe) in the range of a magnetic field with a strength of ±1 Oe. In conclusion, promising directions of the development of magnetic field converter (MFC) structures based on nanostructures with the STMR effect are described.

Magnetic properties of two-phase granular semiconductor–ferromagnet GaSb–MnSb films obtained by pulsed laser deposition as a function of growth temperature and postgrowth annealing were stu-died.

Experiments have been carried out to study the effect of the size and shape of cutouts in steel plates on the difference in the arrival time of acoustic emission pulses at receiving transducers. The data obtained were compared with the results of a numerical simulation of the propagation of elastic waves in plates with various strip and circular cutouts. The research results indicate that the shape of the cutout has a much lesser effect on the time of recording pulses by the transducers of an antenna array than the size of the cutout and the location of the receiving transducer relative to the shading zone—the edge of the cut-out. Based on the results of studies in a 40-mm–thick steel plate with a central 100 mm hole, the accuracy of locating an acoustic emission source near the edge of the hole was estimated. Studies have shown that, in this case, to reduce the measurement error to less than 10% of the antenna-array base size, the location group must include at least four transducers. Numerical simulation of the propagation of acoustic emission pulses in plates with strip and circular cutouts made it possible to significantly reduce the volume of experimental studies, while increasing their information content.

Recently developed non-functional derivatives of polymethylsilsesquioxane (PMSSO) dendrimers of the first to fifth generation were characterized by 1H, 13C and 29Si NMR spectroscopy. The self-diffusion and NMR relaxation of PMSSO dendrimers in dilute solutions of toluene and melts were investigated in a wide temperature range (-50-80 °C). The hydrodynamic radii of dendrimers were determined from the self-diffusion coefficients measured in diluted solutions according to the Stokes-Einstein equation. The hydrodynamic radius of PMSSO dendrimers as a function of molecular mass follows a power law with the scaling exponent of 0.32 ± 0.02 in the investigated temperature range. The temperature dependences of the self-diffusion coefficients of dendrimers were described by the Arrhenius-type equation. The activation energies of self-diffusion of dendrimers in diluted toluene solutions are identical for different generations while the dependence of activation energy for dendrimers in melts shows a maximum for the third generation (G3) dendrimer. Taking into account the absence of specific interactions in PMSSO dendrimer melts the observed behavior was ascribed to the manifestation of interpenetration of dendrimer molecules. For low generations (G1 and G2) the short length of the branches does not considerably affect the translational diffusion while for higher generations (G4 and G5) the densification of the structure prevents significant interpenetration.

Patterns in changes of the microstructure (grain structure) and the thermoelectric properties of the n-type grained Bi1.9Gd0.1Te3 compound, spark-plasma-sintered at different temperatures (TS = 690, 720, 735, 750, 780, and 810 K), have been studied in detail. All the samples studied were highly textured along the 001 direction parallel to the pressing direction, that resulted from preferential orientation of the grains. Orientation factor characterizing a texturing degree and estimated from XRD patterns happened to be weakly TS-dependent. Average grain size measured along the SPS pressing direction was far less as compared to that measured in the perpendicular direction. The thermoelectric properties measured for the perpendicular direction happened to be better than the same properties, but taken for the parallel direction. Of the samples sintered at different temperatures, the highest value of the thermoelectric figure-of-merit equal to ~0.73 for the perpendicular measuring orientation was found for the sample sintered at TS = 750 K. This sample is characterizing by the maximum power factor and the low enough thermal conductivity.

GaInPAs/InP heterostructures grown by metalorganic chemical vapor-phase deposition at a temperature of 600°C and pressure of 0.1 bar are investigated. The thicknesses of the grown GaInAsP layers amount to about 1 μm. For Ga1 –xInxP1 –yAsy solid solutions with average compositions of x = 0.77–0.87 and y = 0.07–0.42, the variation in the content y of V-group atoms over the epitaxial-layer thickness by a value of Δy up to 0.1 atomic fractions in the sublattice of the V-group elements is revealed by secondary ion mass spectrometry. In most cases, a change in y occurs in the GaInAsP layer over a length to 200 nm from the InP heterointerface. In certain cases, y varies throughout the entire GaInPAs-layer thickness. For the epitaxial layers with satisfactory crystalline perfection, the value of Δy is less in the case of better lattice-matching between the GaInPAs epitaxial layer and the substrate. For GaInPAs layers strongly lattice-mismatched with the substrate and characterized by a low degree of crystalline perfection, the value of Δy is close to zero. All these facts enable us to assume that it is elastic deformations arising in the forming monolayer lattice-mismatched with the growing surface that affect the incorporation of V-group atoms into the forming crystalline lattice.

Technological factors and processes contributing to the scintillation mechanism have been considered in quaternary garnet ceramics doped with Ce(Gd,Lu)3Al2Ga3O12. The super-stoichiometric additive of gadolinium in the material composition or its co-doping with a low concentration of Mg were found to be effective tools to suppress phosphorescence in the quaternary garnet, confirming that it is not an intrinsic property of the material. The Monte-Carlo simulation of electronic excitation transfer demonstrates that the hopping migration along the gadolinium sublattice plays an essential role in forming the scintillation kinetic parameters. Breaking the integrity of the gadolinium sublattice by substitution with heavier lutetium ions increases the role of self-trapped states in the excitation of Ce3+ ions, which ensures both an increase in the fraction of short ~20 ns and very long ~600 ns components in the scintillation kinetics.

Numerical simulation of the interaction of the current layer in the magneto-gasdynamic channel with the induction of external magnetic fields of 1, 2, and 4 T and various load resistance values has been carried out. Features of the energy balance and differences in the temperature profiles in the current layers, which were both streamlined by a nonconducting gas flow and completely covered the channel cross section and interacted with the flow like a piston, are revealed. The dependences on the load resistance are obtained for the current, coefficients of current-layer permeability, and enthalpy conversion.

—Design and fabrication of photosensitive array elements in the 384 × 288 element format with a step of 25 μm with a long wavelength limit of sensitivity at 0.5 to approximately 9.5 μm were performed. The circuit and topology were developed, according to which matrix high-speed multiplexers are manufactured in the form of 384 × 288 elements with a step of 25 microns, which provide operating modes at a clock frequency of up to 20 MHz. The 384 × 288 element hybrid photodetector (PD) format in 25 μm increments has an average Noise Equivalent Temperature Difference (NETD) of less than 30 mK, while the number of working elements was more than 97%. Examples are given of using the microscanning system to reduce defective pixels in an image frame and/or increase the frame format to 768 × 576. It is shown that as a result of the use of microscans in a thermal imaging channel based on the developed PD during the transition to the 768 × 576 format, an improvement in spatial resolution of 1.4 times was obtained for the same minimum resolved temperature difference (MRTD), while the MRTD at a frequency of 0.44 mrad-1 decreased from 1.6 to 0.9 K compared to the original 384 × 288 format.

A comparison of the features of electron transport in diodes based on 6-, 18-, 30-, 70-, and 120-period GaAs/AlAs superlattices with a similar design is performed. However, the number of periods and diode areas are different. The values of the parasitic resistances of the near-contact diode regions are correlated, and the specific voltage drop across one superlattice period is determined for all special points in the current–voltage characteristics of the diodes. The mechanism of the appearance of stable current oscillations in diodes based on 6-, 18-, 30-, 70-, and 120-period GaAs/AlAs superlattices with a high doping level is investigated.

The structural–phenomenological approach used to classify and split acoustic-emission signals into energy clusters, together with the parameters of detection frequency and weight content of location pulses in the clusters, allows real-time monitoring of main trends in damage accumulation at different structural levels and makes it possible to isolate signals generated during the failure of a structural material from accompanying mechanical interference and electromagnetic noise. An example of applying new criterion parameters to determining the moment of delamination of stringer runoffs from the shelves of the MC-21 airframe support strut under conditions of fatigue tests with a symmetric loading cycle is provided. Using the new criterion parameters and developed cluster-analysis techniques, employed, among other things, to discriminate location pulses in the field of spectral characteristics, an interconnection has been established between the process of breaking cohesive and adhesive bonds in the adhesive layer at the boundary between the stringer runoff fastening and the support strut shelves and the generated acoustic signals by their energy, waveform, and spectrum.