Abstracts archive – Issue 15 (2023)

1. EXPERIMENTAL STUDIES OF NANOPARTICLES, NANOSYSTEMS, AND NANOMATERIALS – page 8

Alemasova N.V., Bugorskaya D.I., Burkhovetskii V.V., Volkova G.K., Glazunova V.A., Zelenskii M.Yu., Savoskin M.V.
Graphite oxide: peculiarities of investigation of this material by physical methods – page 8
Abstract: It is shown by physical methods that the preliminary preparation of samples affects the structure and properties of graphite oxide and partially reduced graphite oxide. The graphite oxide drying technique as the last synthesis stage determines its morphology and structural properties. At drying by sublimation method, the state of graphite oxide in aqueous suspension before the beginning of the process of self-ordering of its sheets is fixed, the data of X-ray diffraction analysis testifies its X-ray amorphous state, the dried graphite oxide appearance is a light yellow powder. Drying of graphite oxide aqueous suspensions at temperatures above room temperature is accompanied by the ordering of the graphite oxide structure under the action of the surface tension and Van der Waals orces with the dark brown film formation. It is shown by scanning and transmission microscopy methods that the method of separation of partially reduced graphite oxide from glass substrates, on which the product is dried, can lead to the formation of wrinkled or roll-shaped structures. When graphite oxide is examined by transmission electron microscopy, even a short exposure to ultrasound (used in the conventional method of depositing the material on a copper grid prior to examination) results in wrinkling and partial curling of the edges of graphite oxide nanoparticles. Mechanical grinding of graphite oxide leads to disordered graphite oxide structure and to the interplanar spacing increase.
Keywords: graphite oxide, structure, surface morphology, scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis.

Anofriev V.A., Antonov A.S., Ivanov D.V., Semenova E.M., Ivanova A.I., Tretiakov S.A., Afanasiev M.S., Sdobnyakov N.Yu.
Formation pattern of fractal relief for nanosized molybdenum films – page 17
Abstract: Some patterns of formation of the fractal relief of nanosized molybdenum films on the mica surface are considered using the atomic force microscopy. The tools and techniques for postprocessing and analyzing 2D images acquired through this specific research methodology have been thoroughly investigated. The significance of the contributions of errors and uncertainties to the final outcome of the acquired data is discussed. Additionally, a threshold detection method was applied to analyze the fractal dimension, allowing for the identification of areas of interest and exclusion of noise components, as well as regions not having scientific significance. The fractal dimension of the obtained agglomerates was determined at various scales, ranging from 0,5 to 3 µm. The next value D_c = 2,19 and D_c = 2,45 were obtained for the original images; D_c = 2,13 and D_c = 2,45, respectively, for the images processed using the threshold detection method. The obtained data provide prospects for further research and development of novel methods for synthesizing materials with specific properties.
Keywords: atomic force microscopy, magnetron sputtering, fractal dimension, molybdenum films, software.

Bernatskii D.P., Pavlov V.G.
Determining the evaporation energies of alkali and alkaline earth metal atoms using field desorption – page 32
Abstract: The desorption of cesium and barium atoms from a quasi-spherical nanostructured surface of a field emitter has been studied using the method of field desorption microscopy. The dependences of the desorbing electric field strength on the degree of cesium and barium coating of the rhenium and tungsten field emitter at migration equilibrium are obtained. Migration equilibrium occurs at a certain emitter temperature when, due to the surface diffusion, the concentration of adsorbate is redistributed on various surface areas depending on the local heat of evaporation of adatoms from these areas. It is shown that when the migration equilibrium condition is met on the nanostructured surface of the field emitter, on which there are flat low-index crystal faces with different output work, the desorption has an avalanche-like character with the removal of the entire adsorbate. This behavior of the field desorption is characteristic of atoms of alkaline and alkaline earth metals, associated with a sharper increase in the work function compared with an increase in the evaporation energy of the atom with a decrease in the adsorbate concentration. As a result, the ion desorption energy decreases with an avalanche-like increase in the desorption rate. Taking into account the same desorbing field on all parts of the surface, which follows from the characteristics of Fowler Nordheim, the heat of evaporation of adsorbate atoms on different parts of the surface with different work function is determined within the framework of the image forces model for field desorption.
Keywords: field desorption microscopy, atom evaporation energy, field emitter, rhenium, tungsten, alkaline and alkaline earth metals, migration equilibrium.

Bernatskii D.P., Pavlov V.G.
Field desorption of caesium and barium from graphen nanoclueters on the iridium surfaces – page 40
Abstract: The features of the field desorption of caesium and barium from the surface of an iridium tip with two-dimensional graphene nanoclusters on the surface are investigated. Both adsorbates are located both on the surface of iridium and carbon clusters, and in the intercalated state under the graphene film in the close packed planes of the iridium crystal. Field desorption proceeds in different ways. With an increase in the intensity of the applied electric field, the pulse removal of the adsorbate from the surface occurs. With further strengthening of the field in the case of caesium, desorption of adsorbate atoms from the intercalated state occurs. Caesium atoms come out from under the film, diffuse onto the surface of the cluster and are desorbed in the ion form. Barium atoms remain under the graphene film until the cluster is destroyed. The difference in the mechanisms of field desorption from graphene clusters is explained by the presence of a second electron on the valence shell of alkali metal atoms, which provides a chemical bond between the adsorbed atoms and the substrate. The only valence electron of alkali metal atoms during adsorption goes into the metal, and provides an electrostatic bond of the adsorbate with the substrate and electrostatic repulsion of the adatoms among themselves.
Keywords: field desorption, clusters, carbon, iridium, caesium, barium.

Bobreva L.A., Sidorov N.V., Palatnikov M.N., Gosteva A.N.
Investigation of the structural features of LiNbO₃:Gd (0.002-0.26 wt.%) crystals by IR absorption spectra in the region of valence vibrations of hydrogen bonds – page 46
Abstract: Nonlinearly optical single crystals LiNbO₃:Gd (0.001-0.26 wt.%) were grown by theCzochralskii method using the technology of direct doping charge of congruent composition. The defect structure of crystals in the region of valence vibrations of hydrogen bonds was studied by IR absorption spectroscopy. It was found that in the region of small concentrations of the doping impurity gadolinium on the IR spectrum there is a decrease in the widths of absorption bands. The gadolinium impurity with the concentration of 0.26 wt.% leads to a significant deformation of the oxygen octahedron due to the large ionic radius of the gadolinium cation and an increase in the O-O length. A new absorption band at 3488 cm^-1 corresponding to the V_Li-OH complex defect is registered on the IR spectrum. The calculation of the volume concentration of OH-groups showed the lowest value for LiNbO_3congr crystal and the highest for LiNbO₃:Gd(0.005 wt.%), which is related to the process of doping impurity entring into the structure and the increase in the number of point defect centers V_Li necessary to compensate the structural defect Gd_Li²⁺.
Keywords: lithium niobate, defects, IR spectroscopy, hydrogen bonds, complex defects.

Bobreva L.A., Sidorov N.V., Palatnikov M.N., Pyatyshev A.Yu.
Features of the localization of dopping cations Tb³⁺ in a LiNbO₃ crystal in the concentration range 0,1-2,21 wt.% – page 55
Abstract: LiNbO₃:Tb (0,1 wt.%), LiNbO₃:Tb (0,48 wt.%), and LiNbO₃:Tb (2,21 wt.%) crystals were studied by the infrared absorption spectroscopy in the area of valence vibrations of OH- -groups. These crystals were grown by Czochralski method employing direct alloying of blend of the congruent composition. It was found that when the concentration of point defect centers of the cationic sublattice V_Li was higher, than the concentration of impurity point defects Tb_Li, an absorption band with the frequency of 3487cm^-1  was registered in the IR spectrum. This absorption band is associated with the violation of stoichiometry and the formation of a complex defect (V_Li – OН) in the LiNbO₃:Tb (0,1 wt.%), and LiNbO₃:Tb (0,48 wt.%) crystals. A further increase in the concentration of the alloying impurity leads to a change in the O-O bond length, which affects the OH-bond length and the appearance of a new absorption band with a frequency of 3493 cm^-1, which corresponds to the complex defect (Tb_Li – OН) in the LiNbO₃ crystal. Due to non-uniform admixture in the LiNbO₃:Tb crystal, clusters are formed to which the absorption bands with frequencies in the range of from 3100-3403 cm^-1 to 3510-3580 cm^-1 in the spectrum.
Keywords: single crystal, lithium niobate, rare-earth ion, valence group vibrations, complex defects.

Bolshakova N.N., Druginina N.Yu., Ivanova A.I., Ivanov D.A., Semenova E.M.
Hysteresis properties of PIN-PMN-PT single-crystal solid solutions – page 64
Abstract: The paper presents the results of a study of hysteresis properties based on analysis of dielectric hysteresis loops and temperature dependences of switchable polarization for solid solutions 24% Pb(In_1/2Nb_1/2)O₃ – 49% Pb(Mg_1/3Nb_2/3)O₃ – 27% PbTiO₃ solutions. It follows from the experiment that at T = 293 K and strengths of the repolarizing field E = (140-301)·10³ V·m^-1, only partial switching of the crystal occurs. Saturated dielectric hysteresis loops of crystals are observed in a field of 271·10³ V·m^-1 in two temperature ranges 373-383 K and 437-440 K. The temperature dependences of the permittivity and switchable polarization have two anomalies, the first of which correspond to the region of the phase transition of the crystal from the ferroelectric rhombohedral phase to the tetragonal one. At a temperature of about 450 K, the crystal passes into the paraelectric state. Electron microscopic studies of the PIN-PMN-PT crystal structure show that various surface areas contain inhomogeneities that differ in the compositional contrast from the matrix represented by chemical elements, the main mass percentage of which is oxygen and lead. The elemental composition of heterogeneities also includes titanium.
Keywords: single crystal solid solution, hysteresis, switching processes, permittivity, phase transition.

Bukreev A.P., Muratova E.N., Moshnikov V.A.
Film irradiation of perovskite structures with charged particles – page 75
Abstract: Hybrid halide perovskites of the ABX₃ composition are promising materials for use in optoelectronics and photovoltaics. To enhance the efficiency of structures based on perovskite, simulating the influence of the environment on the structures in laboratory conditions, irradiating them with various charged particles, has become a relevant task. This study explores possible irradiation methods for films with perovskite structures using various charged particles, such as alpha and gamma particles, protons, and electrons. Additionally, the impact of these processes on the properties and application domains of such structures is assessed. The research results showed that films based on perovskites (for example, CsPbBr₃) have a very fast response (τ ∼5 ns) to irradiation with both alpha particles (with energy of ∼5 MeV) and protons. At the same time, they have the ability to fully restore to the initial conditions in a few hundred milliseconds after the cessation of irradiation. It has been shown that organic-inorganic hybrid perovskites are more sensitive to the action of an electron beam than inorganic onesAn increase in the dose of gamma irradiation leads to a decrease in the band gap (from 2,35 to 2,14 eV), a shift in the photoluminescence peak towards longer wavelengths and a decrease in the resistance of the grain boundaries. The effect of the gamma radiation dose on properties makes perovskite thin films very useful as sensor materials.
Keywords: perovskites, irradiation, charged particles, solar energy, photoluminescence, ion beams, detectors.

Efremov I.N., Masloboeva S.M., Biryukova I.V., Teplyakova N.A., Palatnikov M.N.
Investigation of acoustic, optical and photorefractive properties of multicrystals of lithium niobate doped with zinc in the area of concentrations of 5,38-9,0 mol.% Zn – page 85
Abstract: Obtaining optical materials based on lithium niobate with controlled optical properties is animportant task of  modern materials science. To date the problem of obtaining heavily doped LiNbO₃ crystals of optical quality with a macroscopically uniform impurity distribution has not been solved. In this work a comparative analysis of studies of the acoustic, optical and photorefractive properties of LiNbO₃:Zn lithium niobate single crystals obtained by direct and homogeneous doping from melts with concentrations of 5,38-9,0 mol% Zn has been carried out. The following methods have been used: piezoacoustics, photoinduced light scattering and laser conoscopy. The values of the static piezoelectric modulus have been determined. According to these values, all crystals are single-domain. Studies of crystals have confirmed the absence of a photorefractive effect in them. It was established that LiNbO₃:Zn crystals grown on the basis of the method of homogeneous doping with concentrations in the melt of 6,8-9,0 mol% Zn are characterized by the highest structural and optical uniformity. This is of interest for the technology of growing large zinc-doped lithium niobate crystals by the Czochralski method.
Keywords: lithium niobate, zinc doping, single crystal, static piezoelectric module, photoinduced light scattering, laser conoscopy, optical uniformity.

Zigert A.D., Dunaeva G.G., Kuz`min N.B., Semenova E.M., Sdobnyakov N.Yu.
The fractal dimension behaviour of the domain patterns in ferrite-garnet films – page 98
Abstract: In this work, using a set of experimental techniques and specialized software, we studied bismuth-containing ferrite garnet films of various thicknesses and with different stoichiometric compositions grown on gadolinium gallium garnet substrates. The limiting magnetic hysteresis loops for defective and defect-free sections of films were obtained using the optical magnetometry method. The field dependences of the fractal dimension of magneto-optical images were also obtained. For various compositions and thicknesses of bismuth-containing ferrite-garnet films, ranges of changes in the fractal dimension were obtained. The fractal dimension was determined by the counting cube method. The mutual behavior of the field dependences of the fractal dimension and the first derivative of magnetization with respect to the field dM(H)/dH is analyzed. The characteristic features of the behavior of the first derivative of magnetization with respect to the field dM(H)/dH with a change in the film thickness, as well as for defective and defect-free sections of films, have been established.
Keywords: magnetic films, ferrite garnets, bulk defects, domain structure, fractal dimension, dM(H)/dH dependence.

Ivanov V.V., Malyshkina O.V., Kislova I.L., Ivanova A.I., Solnyshkin A.V.
Structural features and dielectric response of barium-strontium titanate ceramics – page 108
Abstract: In this work, we carried out a comparative study of the surface structure of bariumstrontium titanate Ba_1-xSr_xTiO₃ ceramics of various compositions (x = 0,1; 0,2; 0,25; 0,3; 0,4 and 0,5) and the dielectric characteristics of samples in a wide temperature range. It has been found that with increasing the strontium content, a decrease in the density of ceramic samples is observed. An increase in the strontium concentration in the composition of the ceramics under study leads to a reduction in the average grain size by an order of magnitude, and fine grains from 2 μm to 200 nm. For all ceramic samples of barium-strontium titanate, there is a deviation of the elemental composition from the stoichiometric at the nanoscale. The closest to the stoichiometric composition in terms of the molar content of elements is the composition of the Ba0_,75Sr_0,25TiO₃ samples. It was found that the samples of this composition have the highest value of the permittivity at room temperature. Temperature studies of the dielectric permittivity showed the existence of two maxima: at a temperature of 130°C, corresponding to the Curie temperature of pure barium titanate ceramics, and at lower temperatures in the range from 10 to 100°C, the second depends on the strontium content. The low-temperature maximum for the ε value corresponds to the diffuse transition of the solid solution Ba_1-xSr_xTiO₃, whose relaxor properties are confirmed by deviation of the temperature dependence from the Curie–Weiss law. The samples of Ba_0,75Sr_0,25TiO₃ composition have the most pronounced relaxor behavior.
Keywords: piezoelectric ceramics, barium– strontium titanate, lead-free materials, grain structure, permittivity.

Klychkov N.A., Simakov V.V., Sinev I.S.
Temperature dependence of Cu:SnO₂ film conductivity in air medium – page 119
Abstract: Temperature conductivity studies of films based on Cu:SnO₂ made by magnetron sputtering of the mixed target CuO/SnO₂ have been carried out. Temperature conductivity dependencies were substantially nonlinear. It was found that the local conductivity minimum was observed near the temperature of 330°C. To explain the results, a mathematical model is proposed of oxygen adsorption in various forms on the surface of wide-bandgap semiconductors. It was assumed that oxygen particle adsorption resulted in energy levels of the acceptor type localized near the surface of the semiconductor. The simulation carried out within the proposed model showed qualitative and quantitative consistency of the calculation results and experimental data of the temperature dependence of conductivity of the formed gas-sensitive Cu:SnO₂ layers in oxygen-containing atmosphere. An analysis of experimental temperature dependence showed that the local conductivity minimum is due to the process of dissociation of oxygen particles adsorbed in molecular form. The desorption energies of each form of adsorbed oxygen and the depth of their surface acceptor level are assessed.
Keywords: temperature dependence of conductivity, oxygen dissociation, tin dioxide, gas sensitivity model.

Kozodaev D.A., Gagarina A.Yu., Spivak Yu.M., Moshnikov V.A.
Structures on heteroepitaxial layers of PbTe(111)-ON-Si with stepped submicron surface relief – page 127
Abstract: A metrological stepped surface with atomically smooth edges, the heights of which have a calibrated size that is a multiple of the height of one monolayer, was obtained by using the example of epitaxial layers of lead telluride with a sublayer of calcium fluoride on (111) single-crystalline silicon substrate. The morphology of the relief was studied using atomic force microscopy. An assessment was made of the stepped relief resulting from the occurrence of mechanical stresses at the «epitaxial layer-substrate» interface. It has been established that the side walls of the steps are cut along crystallographic planes belonging to the {100} set and the walls of the steps are inclined at angles of 54,7° and 144,7° to the plane of the base of the test sample. Recommendations are proposed for the use of calibration samples for a series of epitaxial layers of lead telluride to evaluate the instrumental function of probes.
Keywords: scanning probe microscopy, atomic force microscopy, lead chalcogenides, nanomaterials, test sample.

Korolkov O.E., Stolyarov V.V.
Stress relaxation under tension by accompanyed current in ultrafine-grain titanium – page 135
Abstract: The article studies the effect of stress relaxation caused by strain stops and pulsed current on the tensile deformation behavior of Grade 4 ultrafine-grained titanium. The samples were deformed in the following modes: without current; continuously with current; with periodic current supply, periodic current supply during stops of strain. The microhardness of the working zone of the tested specimens was studied. Fracture studies of the failure zone were carried out. It is shown that, as a result of the continuous introduction of current during tension, the flow stresses decrease, and the elongation to failure increases. Periodic introduction of current, accompanied by strain stops, leads to a maximum increase in the relative elongation to failure due to stress relaxation. The relaxation effect of the pulsed current is manifested in a decrease in microhardness and the transition of the fracture type from a dimple-cup fracture to a predominantly dimple fracture.
Keywords: stress relaxation, tension, titanium, nanostructure, electroplastic effect, pulsed current, microhardness, fractography.

Kramynin S.P., Zobov E.M., Zobov M.E.
On the possibility of decomposition of complex photoluminescence spectra – page 148
Abstract: A method is proposed for decomposing the integrated photoluminescence spectrum into components based on the analysis of an identifier, which is the ratio of the first and second derivatives of the experimental data. The question of the limits of applicability of this method of decomposition of a complex photoluminescence spectrum has been studied in this paper. The definition of the sensitivity of the method is given on the example of an integral spectrum formed by two Gaussians. The evolution of the dependence of the used identifier on the wavelength is shown with a change in the distance between the maxima of the elementary components. By means of a synthetic experiment, dependences of the sensitivity on the ratio of the half-widths and intensities of the components of the integral spectrum are plotted. The dependences obtained are non-linear and have local maxima and minima. The use of the calculated dependences makes it possible to estimate at what overlap of the bands the decomposition is still possible, and at what it is no longer possible to separate the elementary component from the integrated spectrum.
Keywords: photoluminescence, spectrum, decomposition, ZnS, ZnO, modeling, integrated spectrum, Gaussian, luminescent analysis, synthetic experiment.

Lapin V.A., Kravtsov A.A., Suprunchuk V.E., Tarala L.V., Medyanik E.V., Malyavin F.F.
Synthesis and investigation of properties of composite ceramics LuAG: Ce / Al₂O₃ – page 157
Abstract: The purpose of this work was to study the effect of the aluminum oxide impurity content onthe features of  vacuum sintering, optical and luminescent properties of composite ceramics LuAG:Ce / Al₂O₃. Ceramic powders LC-1, LC-2, LC-3 of the composition Lu_2,98Ce_0,02Al₅O₁₂ / Al₂O₃ were synthesized, where the corundum content was 0, 10, 20 wt.% respectively. The dynamics of shrinkage of ceramic compacts by dilatometry, morphology and elemental analysis of the surface of sintered ceramics LuAG are investigated: Ce / Al₂O₃ – by scanning electron microscopy. Light transmission and luminescence spectra were obtained. It is shown that with an increase in the content of corundum in the composition of ceramic powder, the temperatures of the beginning and end of shrinkage increase. In this case, the residual porosity is concentrated in areas of ceramics containing mainly corundum crystallites, as a material with a higher sintering temperature. It was revealed that the inclusion of the corundum phase prevents the uncontrolled growth of ceramic grains. Composition with a corundum content of 10 wt.% showed the highest value of luminescence intensity. At the same time, with an increase in the proportion of corundum in composite ceramics, a slight broadening of the luminescence spectra was observed.
Keywords: : LuAG:Ce, ceramics, aluminum oxide, luminescence, optical properties, sintering.

Lyakhova M.B., Semenova E.M., Rakunov P.A., Karpenkov A.Yu., Sinkevich A.I., Fedorov M.V.
Hysteresis structure and magnetic properties of (R, Zr)(Co, Cu, Fe)_Z (R = Sm, Gd) alloys – page 169
Abstract: The results of an experimental study of magnetization reversal processes of (R,Zr)(Co,Cu,Fe)_Z (R = Sm, Gd) alloys taking into account micro- and nanostructure are presented. To create a highly coercive state in the samples, they were isothermally annealed at 800°C for 8-24 hours. The duration of annealing affects the formation of the nanostructure of alloys of this type. Based on magnetic measurements performed using a vibration magnetometer, magnetic hysteresis loops and graphs of the dependence of the coercive force on the chemical composition and duration of heat treatments were obtained, and the range of changes in the temperature coefficient of magnetic induction was determined depending on the relative content of Sm and Gd in the samples. Data on micro- and nanostructure were obtained using optical and scanning probe microscopy. The correlation relationships between the micro- and nanostructure parameters and the magnetic properties of the studied alloys are described. It was found that the highest values of the coercive force are achieved in an alloy in which the value is x = 0,5.
Keywords: rare earth intermetallic compounds, hysteresis, coercive force, magnetization, microstructure, nanostructure.

Mitchenko A.S., Malyshkina O.V., Guseva O.S., Ivanova A.I.
Stabilization of the dielectric properties of solid solution ceramics based on calcium–barium niobate – page 178
Abstract: In this work, we studied the effect of a modifying additive of finely dispersed polystyrene (2 wt.%) on the dielectric and pyroelectric properties of the ceramic samples Ca_0.3Ba_0.7Nb₂O₆ (CBN30) and solid solutions based on it with the addition (5%) of SrTiO₃ or LiTaO₃, obtained by the solid-phase synthesis method. It is shown that the presence of polystyrene during the sintering of solid solution ceramics based on CBN30 leads to the formation of nanosized pores in the samples and, as a result, leads to a significant decrease in the dielectric losses and a change in the nature of the permittivity dispersion in a wide frequency range of fabricated samples. As a result, the shape of the dispersion diagrams of the ceramics based on CBN30 became similar to the dielectric dispersion of industrial samples of the piezoelectric ceramics of lead zirconate-titanate. The studies of the pyroelectric effect on polarized ceramic samples based on CBN30 revealed that the samples sintered with the presence of polystyrene, in contrast to the samples sintered without polystyrene, have a uniform polarization distribution over the thickness.
Keywords: piezoelectric ceramics, barium-calcium niobate, lead-free materials, modifiers, grain structure, permittivity.

Molokanova O.O., Karmokov A.M., Molokanov O.A., Karmokov M.M., Khasanov A.I., Dyshekova A.Kh.
Fundamental absorption and band gap of glasses S87-2, S78-4, S78-5 – page 189
Abstract: In special glasses for electronic technology of brands S87-2, S78-4 and S78-5, the effect of thermal processes on the spectra of optical absorption in the wavelength range from 200 to 1100 nm was investigated. Glasses were studied both in the initial state and after annealing at various thermodynamic conditions: in an atmosphere of natural air and in vacuum at temperatures of 400 and 500°С, as well as in flow-through hydrogen at a temperature of 400°С. The influence of the medium, temperature and annealing time on the dispersion dependences of the absorption of the studied glasses was established. It was found that the time of absorption by some glass components has a significant effect on the own absorption of annealing in hydrogen. The edge of the fundamental absorption is determined and the width of the prohibited zone of the resulting nanocrystalline phases is estimated. The width of the prohibited zone of the nanocrystalline phases formed during the annealing of samples at high temperature, according to the results of optical measurements, is from 2,0 to 3,7 eV.
Keywords: glasses, intrinsic absorption, nanocrystal, band gap.

Staritsyn M.V., Kiselev D.A., Pronin V.P., Krushelnitsky A.N., Senkevich S.V., Kaptelov E.Yu., Pronin I.P.
Peculiarities of the microstructure and properties of thin spherolitic PZT films formed by a two-stage radiofrequency magnetron deposition method – page 196
Abstract: The paper presents the results of experimental studies of the microstructure and piezoelectric properties of thin lead zirconate-titanate films characterized by either an island structure of radially radiant spherulites located in a low-temperature pyrochlore matrix or a block single-phase spherulitic structure with different linear block sizes. Changing the size of the blocks within 10-50 µm was achieved by varying the distance from the target to the substrate in the range of 30-70 mm, leading to a change in the heating temperature of the substrate in the radio-frequency magnetron sputtering of a ceramic target during film deposition on a «cold» platinized silicon substrate. The temperature of subsequent annealing for the crystallization of the perovskite phase was 550°C for island films and 580°C for single-phase films. Scanning electron microscopy methods have revealed anomalous dependences of the rotation of the growth axis with the growth of the linear dimensions of spherulites, reaching a value of 1,2 deg/μm, and other microstructural parameters of thin films. The observed phenomena were caused by lateral mechanical stresses arising during the solid-state transformation from the pyrochlore phase to the perovskite phase, accompanied by a change in the density of the films. At tensile stresses of the order of the elastic limit, this led to the appearance of intra-block high-angle boundaries. The behavior of lateral polarization was studied by the method of force microscopy of the piezoelectric response and it was shown that tensile mechanical stresses in spherulites lead to the orientation of the lateral polarization vector in the radial direction.
Keywords: lead zirconate-titanate thin films, pyrochlore-perovskite phase transformation, spherulite microstructure, piezoresponse force microscopy.

Teplyakova N.A., Sidorov N.V., Palatnikov M.N.
Optical properties of double doped LiNbO₃:Gd:Mg crystals – page 207
Abstract: By direct alloying of congruent melt with magnesium and gadolinium oxides, compositionally uniform nonlinear optical single double doped crystals with different content of dopants have been grown: LiNbO₃:Gd³⁺(0,003):Mg²⁺(0,65 wt. %), LiNbO₃:Gd³⁺(0,23):Mg²⁺ (0,75 wt. %) and LiNbO₃:Gd³⁺(0,25):Mg²⁺(0,75 wt. %). The results obtained by laser conoscopy and photoinduced light scattering indicate a high structural perfection of the grown crystals. The results give grounds to assert that LiNbO₃:Gd:Mg crystals are close to a stoichiometric crystal in some of their properties. A low value of the coercive field (≈2,3 kV/cm) is one of such properties of stoichiometric and magnesium-doped LiNbO₃ crystals, which are important for creating materials for laser radiation conversion on periodically polarized submicron-sized domains with flat boundaries. In this case, the grown LiNbO₃:Gd:Mg crystals have a much higher optical uniformity than a stoichiometric crystal. Crystals of LiNbO₃:Gd³⁺(0,003):Mg²⁺ (0,65 wt. %) and LiNbO₃:Gd³⁺(0,23):Mg²⁺ (0,75 wt. %) have the highest optical uniformity and the absence of the photorefraction effect. Increase of gadolinium concentration to 0,25 wt. % leads to increased distortion of the conoscopic pattern and to the appearance of a significant photorefractive response of the LiNbO₃:Gd³⁺(0,25):Mg²⁺(0,75 wt. %) crystal.
Keywords: lithium niobate, crystal, defects, laser conoscopy, photorefractive properties.

Teplyakova N.A., Sidorov N.V., Palatnikov M.N.
Features of the defect structure of a LiNbO₃:Cu (0.015 wt.%) single crystal – page 215
Abstract: By direct alloying of melt with copper oxide, а compositionally uniformity LiNbO3:Cu (0,015 wt%) single crystal doped with a photovoltaically active copper dopant has been grown. The optical properties of the single crystal have been studied by photoinduced light scattering. The values of the diffusion and photovoltaic fields were calculated for the studied crystals based on the intensity and magnitude of the opening angle of the speckle structure of the photoinduced light scattering. Significant differences in the photoinduced light scattering patterns and in the values of the photoinduced light scattering photoelectric parameters of nominally pure crystals of congruent and stoichiometric compositions and a LiNbO3:Cu (0,015 wt%) crystal have been found. It has been established that when a congruent lithium niobate crystal is doped with copper cations, the diffusion field increases, the photofoltaic field decreases, and the band gap in the crystal decreases noticeably. In contrast to the crystal of stoichiometric compositions, the photovoltaic mechanism remains the predominant mechanism of photorefraction for crystals of congruent composition and LiNbO3:Cu (0,015 wt%). Photoinduced light scattering data indicate the presence of a LiNbO3:Cu(0,015 wt.%) crystal in the band gap high density of small energy levels that increase the effect of photorefraction and electrical conductivity of the crystal.
Keywords: lithium niobate, crystal, defects, photorefractive properties, photovoltaic fields, band gap.

2. THE THEORY OF NANOSYSTEMS – page 223

Andre E., Tsirulev A.N.
Model of a three-qubit cluster in a thermal bath – page 223
Abstract: This work studies a mathematical model of a quantum cluster consisting of three qubits and being in thermal equilibrium with the environment. The effective Hamiltonian is invariant under permutations of qubits and consists of two parts. The first part is similar to the Heisenberg XYZmodel with internal two-qubit interaction, while the second includes three-qubit interaction with the thermostat. Such a quantum system admits a fully analytical investigation and is considered in the context of mathematical modeling of quantum metamaterials, in which nanoclusters are elementary structural units with the strong internal interaction of qubits and the relatively weak coupling with the environment. For the Hamiltonian, we construct an orthonormal basis of eigenvectors, which includes the maximally entangled W-state. We also obtain the density operator of the cluster state in explicit form, and study the temperature dependences of the thermodynamic characteristics of the cluster: the partition function, entropy, and free energy. It is shown that the conditions of thermal equilibrium in this quantum system are satisfied at temperatures from 0,2 K to microkelvins, which correspond to the operating range of modern quantum logic elements and quantum simulators.
Keywords: cluster of qubits, Hamiltonian, Pauli basis, operator exponential, density operator of a state, Gibbs-von Neumann state, partition function, entropy, free energy.

Apekov A.M., Shebzukhova I.G.
Contribution of the dispersion interaction to the interface energy of cobalt crystals at the boundary with nonpolar organic liquids – page 231
Abstract: The active implementation of devices based on the use of the properties of the metalorganic interface makes it important to study characteristics of such interfaces, especially of the metalorganic framework structures. The of these structures with the necessary properties is possiblesince one can vary the elemental composition in the  active metal centers as well as the organic ligandsbinding these centers. In this regard, understanding the  properties and nature of the interaction at the interface of a metal with organic substances becomes of primary interest. In this work, within the framework of the electron-statistical method, a correction to the interfacial energy of cobalt at the interface with non-polar organic liquids for the dispersion interaction of the Wigner-Seitz cells is obtained. The dependences of the dispersion correction on the orientation of the metal crystal and the permittivity of the organic liquid are determined. It is shown that the contribution of the dispersion correction to the interfacial energy is positive and decreases with an increase of the permittivity of the liquid.
Keywords: interfacial energy, dispersion contribution, electron-statistical method, non-polar organic liquid, cobalt.

Aref`eva L.P., Duka V.V., Drogan E.G.
Investigation of the morphology and topology of lamellar and grained pearlite from 1.1625 steel at the submicron level – page 239
Abstract: The paper presents the results of a study of the submicron structure of carbon eutectoid steel by the atomic force microscopy, carried out in accordance with current international standards. The study was carried out on samples obtained in two ways: complete annealing and annealing for granular perlite. The first sample had the structure of lamellar perlite, the second – granular pearlite. The presence of these structures was controlled by optical microscopy and hardness measurements by the Rockwell method. Sample preparation included cutting, grinding, polishing, and etching. The quantitative assessment of the structural components of perlite was carried out using the ImageJ application package. The volume fraction of ferrite was about 88%. The topology and morphology of the surfaces are studied by atomic force microscopy in the discontinuous-contact mode. The amplitude characteristics of the surfaces, the shape and size of the structural components of perlite are determined. It is shown that the performed analysis of the submicron structure makes it possible to uniquely identify the phase components of the steel.
Keywords: eutectoid steel, granular perlite, lamellar perlite, submicrostructure, atomic force microscopy.

Barabanova E.V., Kondratev S.E., Ivanova A.I.
Structure and dielectric properties of Ti-doped KNN ceramics – page 246
Abstract: The work is devoted to investigation of the influence of the technology for producing potassium sodium niobate ceramics with an acceptor impurity Ti⁴⁺ on its structure and dielectric properties. The aim of the work was to determine ways to obtain a single-phase composition of doped ceramics and the role of the TiO₂ modifying impurity. It is shown that the substitution of niobium by titanium for preserves the cubic shape of potassium sodium niobate grains, increases dielectric losses and causes significant migration polarization. The latter leads to the fact that the maximum temperature dependence of the dielectric permittivity at low frequencies is not observed for the studied ceramics. The shift of the phase transition temperature caused by doping is not observed. In all samples, despite the heterogeneity of the elemental composition and grain structure, the phase transition temperature corresponds to the phase transition temperature of pure potassium sodium niobate ceramics.
Keywords: sodium potassium niobate, ferroelectric solid solutions, dielectric permittivity, acceptor dopants, phase transition.

Belyaeva I.N., Korsunov N.I., Chekanov N.A., Chekanov A.N.
Semi-classical calculations of energy levels and wave functions of hamiltonian systems with one and several degrees of freedom based on the method of classical and quantum normal forms – page 255
Abstract: The paper presents two schemes for the sequential construction of the classical normal form and its quantum analogue for some classes of classical Hamiltonian systems. For quantum normal forms, a method for solving their eigenvalue problem is indicated. Based on these normal forms, a semi-classical method for solving Schrodinger equations for classical Hamiltonian systems under their quantum consideration is proposed. With this proposed method, some quantum problems were solved and it was found that this method gives a very accurate prediction for energy levels. However, this accuracy in the field of the existence of classical chaos is deteriorating. The same semiclassical method solved the quantum problem for a flat hydrogen atom in a homogeneous magnetic field. The proposed method allows carrying out all calculations using modern computer systems of analytical calculations.
Keywords: classical normal form, quantum analog of normal form, Weyl-McCoy rule, energy levels, eigenfunctions, mathematical modeling.

Kul’kov V.G.
Contribution of grain boundaries with matching planes to internal friction – page 264
Abstract: In nanocrystalline metals, there are grain boundaries that, under the influence of shear stresses applied along them, move along the normal. Such boundaries combine two types of the grain boundary deformation – mutual grain slippage along the boundary and its migration. This relationship is easily explained in the model of intercrystalline boundaries with mating crystallographic planes. By solving the differential equation under the action of alternating voltage, the functional dependence of the boundary displacement on the coordinate and time is found. Based on this, the value of the energy dissipated during the oscillation period and the expression for the internal friction caused by the contribution of such boundaries are found. It has the character of a Debye peak. The activation energy of the process is equal to the activation energy of the grain boundary self-diffusion. An atomic mechanism of the boundary motion is proposed, which is based on diffusion processes between extended steps of atomic scale in the boundary.
Keywords: grain boundaries, crystallites, matching planes, boundary migration, diffusion, vacancies, relaxation time.

Magomedov R.A., Akhmedov E.N.
Calculation of CO₂ P-ρ-T properties in the temperature range from T = 400 K to T = 1700 K – page 274
Abstract: Сalculation of the carbon dioxide state equation isotherms in the temperature range from T = 400 K to T = 1700 K is presented. Implemented calculation method is a refinement of the previously proposed approach based on the fractal state equation and specially developed software Fract EOS. The calculation results are in good agreement with the experimental data. It is shown, that the fitting parameter α of the fractal state equation for carbon dioxide does not depend on temperature. The density dependence can be accurately approximated using the polynomial. This fact simplifies the calculation of isotherms in a wide temperature range, and allowed to make the calculation for temperatures, that are not presented in the tabular reference data. The obtained results show that the proposed equation of state is suitable for studying not only simple substances like noble gases, but also for more complex substances, such as carbon dioxide.
Keywords: equation of state, integral-differentiation of fractional order, Maxwell relations, Helmholtz potential, partition function, carbon dioxide, isotherm, thermophysical properties.

Tvardovskiy A.V.
Simulation of adsorbostriction in microporous adsorbents – page 282
Abstract: In this work, models of elastic adsorption deformation of microporous adsorbents with different micropore geometries are proposed, which make it possible to relate changes in the relative linear dimensions of macroobjects (adsorbents) and micropores. Model No. 1 is a model of elastic adsorption deformation of microporous adsorbents upon interaction with gases. Model No. 2 corresponds to the model when the micropores are plane-parallel slots of limited size. Obviously, the proposed equations can be used in constructing the general thermodynamics of adsorption processes and adsorption theory, as well as in calculating the thermodynamic functions of adsorbents. In particular, changes in the internal energy, enthalpy, and entropy of the adsorbent during its deformation can be calculated. Thus, it will be possible to reveal the contribution of the non-inert adsorbent to the measured heats of adsorption. The developed approach contributes to the development of the thermodynamics of adsorption processes and the construction of a general theory of adsorption, taking into account the contribution of the adsorbent.
Keywords: adsorption, absorption, adsorbostriction, deformation of adsorbents, microporous adsorbents, dilatometric studies, adsorption thermodynamics.

Shebzukhova I.G., Aref`eva L.P.
Surface energy and electron work function for polimorphyc modifications of titanium – page 288
Abstract: In this work, the surface energy of titanium crystal faces was estimated using theelectron-statistical method,  taking into account the contributions of the dispersion, polarization, and oscillation corrections. Using an analytical relationship, the values of the work function of close-packed faces of polymorphic modifications of titanium are calculated from the values of the surface energy of single crystals taking into account the crystal structure. The influence of polymorphic transformation and temperature on the anisotropy of the studied properties is shown. Based on the values of the surface and interfacial energies, which consist of the average configurational energy and the energy of chemical interaction of two parts of the metal, the cohesive energy of α- and β-titanium is estimated and its dependence on temperature is shown. On the example of tungsten-titanium and molybdenumtitanium systems, the fundamental possibility of calculating the change in the work function depending on the concentration of the surface-active component in bimetallic systems is shown, which makes it possible to predict the service life of the material.
Keywords: surface energy, electron work function, anisotropy, polymorphic modifications of titanium, cohesion energy.

Shishulin A.V., Shishulina A.V.
Influence of the initial composition on the phase equilibria in the case of the solid phase separation in binary alloy nanoparticles (exemplifying on the W-Cr system) – page 299
Abstract: Due to a unique set of physico-chemical properties, nanoparticle-fabricated heavy tungstenpseudo-alloys with  the ultrafine-grained structure have become an object of a strong interest among researchers in the case of the up-to-date additive powder metallurgy technologies. In this paper, the peculiarities of the phase composition have been simulated in the framework of a thermodynamic approach to core-shell nanoparticles of a stratifying sold solution using the heavy W-Cr pseudo-alloy as an example. For a two-component system with the phase separation in the solid state, a specific effect has been demonstrated which consists in the fact that, unlike system in the macroscopic state, it is not only the volume fraction of co-existing phases but also their equilibrium composition varies depending on the initial composition of a the system. For two different heterogeneous states of a coreshell structure, the thermal stability areas have been obtained along with temperature-dependent equilibrium phase compositions of the system in each state. A thermodynamic interpretation of the obtained results has been described based on three possible mechanisms of reducing the free energy of the system.
Keywords: nanoparticles, phase separation, chemical thermodynamics, solubility, core-shell, tungsten, chromium.

Shishulin A.V., Shishulina A.V.
Several notes on the elastic properties of mesoporous materials – page 308
Abstract: In this paper, the dependence of the Young’s elastic modulus of a mesoporous material on the geometric characteristics (volume and shape) of pores has been analyzed. The geometric characteristics of pores have been determined in the framework of the fractal-geometry approach by the values of their effective diameter and fractal dimension. The presented estimates demonstrate that the effect (being characteristic of nanoscale particles), which consists a significant dependence of elastic moduli on the size and shape of a particle, can also be realized in mesoporous materials (the pore size being form 5 up to 50 nm) while the mesoporous samples themselves can be of macroscopic dimensions. Using the example of mesoporous silver, it has been shown that reducing the pore size and «complicating» the pore shape lead to a significant decrease in the Young’s elastic modulus. The results have been obtained in the framework of the cohesive energy-based model.
Keywords: elastic modulus, mesoporous materials, fractal dimension, cohesion, size distributions, Hardy-Ramanujan-Rademacher formula.

El Zanin A.R., Boroznin S.V., Zaporotskova I.V., Boroznina N.P., Kozhitov L.V., Popkova A.V.
About the possibility of applying empirical methods of estimation of standard enthalpies of formation of organic compound for fullerenes – page 317
Abstract: Due to the high practical significance and, as a consequence, active study of carbon nanomaterials, the question of methods for investigating their physicochemical, in particular, thermodynamic properties is relevant. In the present work, several approaches are considered to estimate the standard enthalpy of formation of fullerenes in the gas phase. The standard enthalpies of formation of C₆₀ and C₇₀ fullerenes in the gas phase have been calculated using the Laidler, Franklin, Souders-Matthews-Hurd and Joback-Reid methods. A number of analytical dependences of the standard enthalpy of formation in the gas phase on the number of carbon atoms in fullerenes molecules were obtained. The obtained values were compared with experimental data and the relative error of calculation was determined. It is concluded that the proposed methods are limitedly applicable for determination of standard enthalpy of formation of fullerenes in the gas phase. The obtained values of the standard enthalpy of formation by the most satisfactory method from the considered ones for fullerenes C₆₀ and C₇₀ are 2448,90 and 2857,05 kJ/mol, and the relative errors are 4,44% and 5,95%, respectively. This is the Souders-Matthews-Hurd method. The presented analytical dependences allow for an express estimation of the standard enthalpy of formation of fullerenes in the gas phase with a small amount of input data.
Keywords: additive calculation schemes, carbon nanomaterials, thermodynamic properties.

Yurov V.M., Goncharenko V.I., Oleshko V.S.
Primary nanocracks in nitrides, borides, and carbides of refractory metals – page 328
Abstract: A model is proposed that can be used to calculate the length of a nanocrack in a solid body. The nanocrack length in nitrides, borides, and carbides of refractory metals turned out to be in the range 1<L<3 nm. Theoretical and experimental methods for studying nanocracks are discussed. The theory gives a length interval 0<L<2 nm for silicon polycrystals. X-ray and electron microscopic methods give the thickness of cracks in the metal in the range of tenths and hundredths of a micron. The recently proposed method of fractoluminescence for the destruction of minerals with a duration of signals of about 50 ns, and the time interval between them varied from about 0,1 to 1 μs, made it possible to reveal nanocracks in oligoclase during the destruction of its surface in the range of 10<L<20 nm, which coincides with the one in proposed by us model. More examples of the formation of nanocracks in solids can be cited. In other words, we propose to call the direction of condensed matter physics «physics of nanocracks», which differs from the «theory of cracks» both in its experimental detection and in the method of its calculation.
Keywords: nanocrack, surface layer, metal, fracture, surface, model, micron.

Yurov V.M., Zhangozin K.N.
Surface thickness water and ethanol – page 338
Abstract: A theoretical model is proposed that allows one to determine the thickness of the surface layer of liquid R(I). For water and ethanol it turned out to be 1,1 nm. As a result, ethanol is unlimitedly soluble in water. Methyl acetate, benzene and toluene (R(I) of above 1,4 nm) form azeotropic mixtures with water. Glycerol, nitrobenzene and mercury (R(I) greater than 3 nm) are practically insoluble in water. From the proposed model, we can conclude that the surface layer of the liquid is a nanostructure with size effects. It is of interest that the thickness of the surface layer of water coincides with the thickness of the surface layer of iron, cobalt and nickel. The work of adhesion and elastic constants for water and ethanol, including Young’s modulus, were also found. It was established that the elasticity of water is only 100 times less than the elasticity of steel, i.e. water can be considered as an incompressible substance, and the internal friction in water is three times greater than in ethanol. It is also shown that the universal element of the geometry of spaces of liquid systems is the tetrahedron, which corresponds to sp³ hybridization of interatomic or intermolecular bonds.
Keywords: surface layer, water, ethanol, liquid, layer thickness, cluster.

3. FIRST PRINCIPLES AND ATOMISTIC MODELING – page 350

Barbin N.M., Yakupova L.V., Terent’ev D.I.
Thermal stability of fullerenes from the C28-C50 series in a nitrogen atmosphere – page 350
Abstract: In order to study the thermal stability of fullerenes C_n (n = 28, 32, 44, 50) in a nitrogen medium during the transition from the condensed phase to the gas phase and further reactions in the vapor phase, the method of thermodynamic modeling was used. Based on the results of the calculation, chemical reactions in the C_n–N₂ system were compiled and temperature intervals wereidentified for each reaction. In this work, a comparative  study of the thermal stability ranges of C_n fullerenes in the condensed and gas phases has been carried out. As a result of heating, the physicochemical processes occurring in the carbon-nitrogen system are distinguished, which can be divided into three groups: reactions occurring in the condensed phase, between the condensed and gas phases, and sublimation with thermal dissociation. It is clearly demonstrated that with an increase in the number of carbon atoms in the condensed phase, fullerenes exhibit their thermal instability, in contrast to the solid solution of fullerenes. This study is one of a series of works devoted to the properties of nanoparticles in nitrogen atmosphere, which can be used in the development of new flame retardant compositions.
Keywords: fullerenes, thermal stability, thermodynamic modeling, physical and chemical process, chemical reactions.

Blinov A.V., Pirogov M.A., Gvozdenko A.A., Golik A.B., Rekhman Z.A., Kolodkin M.A., Filippov D.D.
Computer quantum-chemical modeling of the interaction of selenium nanoparticles with quaternary ammonium compounds – page 357
Abstract: In this paper, a computer quantum-chemical simulation of the interaction of selenium nanoparticles with quaternary ammonium compounds was carried out, in which models of molecular complexes, electron density distribution, as well as higher populated and lower free molecular orbitals were obtained. For the presented molecular systems, the total energy of the molecular complex E, the difference in the energy of the quaternary ammonium compound molecule and the system «quaternary ammonium compound-selenium nanoparticles» ΔE, the energy of the highest occupied molecular orbital E_HOMO, the energy of the lowest unoccupied molecular orbital E_LUMO, and the chemical rigidity of the system η were calculated. As a result of data analysis, it was found that the interaction of selenium nanoparticles with quaternary ammonium compounds is energetically advantageous (ΔE > 11991 kcal/mol). The optimal system of interaction of selenium nanoparticles with quaternary ammonium compounds is the «cetyltrimethylammonium chloride-selenium nanoparticles» system, which is due to the highest value of the energy difference (ΔE = 11991,79 kcal/mol). Based on the analysis of the obtained models of molecular systems, it was found that when a quaternary ammonium compound interacts with selenium nanoparticles, the electron density is shifted and new molecular orbitals are formed, which indicate formation of a chemical interaction between the molecules. Next, IR spectroscopy of selenium nanoparticles stabilized with cetyltrimethylammonium chloride was performed. Based on the data obtained, it is found that there is a decrease in the intensity of the bands, in comparison with the IR spectrum of cetyltrimethylammonium chloride, in the regions from 2851 to 3026 cm^-1 and from 1265 to 1377 cm^-1, characteristic of the CH₂ and CH₃ groups, which indicates the presence of cetyltrimethylammonium chloride molecules oriented with the hydrophobic side to selenium particles on their surface. After that, the morphology of selenium particles was studied using the transmission electron microscopy method. As a result of the analysis of transmission electron microscopy images, the formation the layer of the quaternary ammonium compound on the surface of selenium particles with a diameter of 25 to 60 nm was confirmed.
Keywords: .

Gafner S.L.
To the problem of application of nanoclusters Ag-Cu in plasmonics – page 367
Abstract: The magnitude of the localized surface plasmon resonance (LSPR) in metal nanoparticles is determined by many factors. Thus, with an increase in their average linear size, the maximum position of the LSPR peak shifts towards long waves. However, the position of the LSPR maximum is affected to a greater extent by the material of the nanoparticles. Changing the average particle diameter fromD = 7 nm to D = 60 nm makes it possible to  vary the position of the LSPR maximum in the range of about 50 nm. However, with a smooth change in the composition of binary nanoparticles, it can already be varied within about 120 nm. Therefore, copper-silver alloy nanoparticles are of great practical interest due to the possibility of fine-tuning the plasmonic effects present in them by changing the composition, size, shape, and structure of the nanoparticles. Based on the results of the analysis of the available experimental data, it was concluded that it is possible to control the internal structure and shape of Ag-Cu nanoparticles in order to shift the plasmon resonance peak and enhance it.
Keywords: : nanoclusters, silver, copper, crystallization, structure, computer simulation, tight-binding.

Gafner S.L., Redel L.V.
Evaluation of the structure and shape of the experimentally obtained Ag nanoparticles – page 377
Abstract: Silver is one of the most promising nanomaterials for plasmonic applications due to its low cost as well as the ease with which it can be prepared into nanoparticles with controlled size and shape. By now, it has already become clear that it is the shape and internal symmetry of nanoparticles that can significantly affect the scattering and absorption of a light wave, since without the formation of a strong dipole, these effects in nanoparticles will be insignificant. Therefore, the main objective of the study was a theoretical analysis of the processes of formation of the external and internal structure of silver nanoclusters obtained by some methods of physical synthesis. To do this, we studied highresolution electron microscopy data for the initial and annealed silver nanoparticles formed on a carbon substrate by vacuum thermal evaporation and having sizes from 2,0 to 10,0 nm. It has been established that, as a result of annealing, the number of small nanoparticles (D< 3,5 nm) decreases by approximately 2 times, and the proportion of nanoparticles with icosahedral and decahedral faceting increases by approximately 1,5 times. Based on the analysis performed, conclusions were drawn about the possible features and mechanisms of formation of various types of symmetry in synthesized Ag nanoparticles.
Keywords: nanoclusters, silver, crystallization, structure, computer simulation, high-resolution transmission electron microscopy.

Gafner Yu.Ya., Ryzhkova D.A., Gafner S.L., Cherepovskaya A.A.
Features of crystallization Ag-Au alloy nanocusters – page 387
Abstract: In the production of SERS (surface enhanced Raman scattering) substrates, two mainapproaches to the  formation of an array of plasmonic nanoparticles are used: photolithography and chemical methods. Each of them has its own advantages and disadvantages. Vacuum thermal evaporation can also be used. It was chosen for analysis by computer simulation. For this, molecular dynamics simulation of the processes of crystallization of an array of binary Ag-Au nanoparticles was used, which makes it possible to smoothly control the plasmon resonance wavelength. Three arrays of Ag-Au NPs with a diameter of 2,0; 4,0 and 6,0 nm of various target compositions from Ag₉₀Au₁₀ to Ag₅₀Au₅₀ were created. They were subjected to the procedure of cooling from the melt with different rates of the thermal energy removal. In the course of modeling the formation of the internal structure of Ag-Au nanoparticles, conclusions were drawn about the dependence of these processes on the target composition, size, and level of thermal exposure. Based on the regularities obtained, adjustments were made to the technological process of creating SERS substrates using binary Ag-Au nanoparticles.
Keywords: nanoclusters, silver, gold, crystallization, structure, computer simulation, tight-binding.

Gafner Yu.Ya., Ryzhkova D.A.
Analysis of absorption processes on the surfaceof a nanocompacted gas sensor – page 395
Abstract: It is well known that gas absorption by a semiconductor surface leads to a change in its electrical conductivity. This phenomenon has become the basis for the technical production of various gas sensitive sensors. Near the particle surface, due to the absorption and subsequent ionization of oxygen molecules, a surface zone is formed that is depleted in free charge carriers. The thickness of this zone is comparable to the Debye length and depends on the oxygen pressure on the particle surface. Depending on the size of the particle and the degree of their connection, there can be either conductive contacts or contacts of the Schottky barrier type between them. All this leads to a different kind of relationship between the conductivity and the concentration of the gas being determined. Since the sensitivity is based on chemical reactions between the surface of a solid body and gas molecules, the most demanded are materials with a large surface-to-volume ratio and a high degree of porosity, i.e. nanoparticles. In the present work, the main possible mechanisms of absorption of gas molecules by compacted nanoparticles are considered and their analysis is carried out.
Keywords: absorption, semiconductors, nanocompacted material, gas sensors, simulation.

Devitsky O.V.
Effect of bismuth content on the structural and electronic properties of GaAs_1-yBi_y: first principles calculations – page 404
Abstract: A theoretical study of the effect of bismuth concentration on the structural and electronicproperties of the  GaAs_1-yBi_y solid solution is presented using the density functional theory in the VASP 5.4.4 software package. The results of the study showed that the fundamental band gap GaAs_1-yBi_y increase in the concentration of bismuth leads to an increase in the GaAs_1-yBi_y lattice constant, which causes internal asymmetry and a decrease in the Ga-Bi bond length. It has been shown that, with an increase in the number of Bi atoms substituting As atoms, a distortion of the position of neighboring Ga atoms and a decrease in the Ga-As bond length are observed at the sites of the crystal lattice. It has been established that these changes are due to the influence of the neighboring Bi atom, which affects the Ga-Bi bond length and reduces its length down to 2,6133 Å at y equal to 12,5%. The angle between the Ga-Bi and Ga-Bi bonds, on the contrary, increases with increasing Bi concentration and can reach a maximum value of 110,9256°. The combination of such structural changes in the crystal lattice of GaAs_1-yBi_y further lead to the emergence of potential defects in the form of clustering of Bi atoms or displacement of the Bi atom in the position of the interstitium. It has been established that supercells have the most stable configuration. GaAs_1-yBi_y with a concentration of Bi atoms up to 12,5%. The band gap of the GaAs_1-yBi_y solid solution decreases from 1,283 eV to 0,712 eV with increasing bismuth concentration from 1,85 mol.% to 12,5 mol.%. The band gap values obtained are, on the whole, close to known literature data. This shows that the direct band gap of this alloy covers the spectral region from the near infrared to the infrared range.
Keywords: III-V-Bi, GaAs1-yBiy, electronic structure, density functional theory, band gap.

Kartashynska E.S.
Conformation peculiarities of gemini surfactant monomers for 2D monolayer formation at the liquid/fluid interface – page 412
Abstract: The present work is devoted to the consideration of gemini surfactant monomers with a nonionic hydrophilic part and a different structure of the spacer connecting the hydrocarbon chains. It is possible to single out two conditional conformations of monomers depending on the spacer type: with an «extended» and «compact» spacer in the case of a flexible etoxylated or hydrocarbon chain, and only with the «extended» rigid spacer in the case of aromatic ring in it. The length for all three types of spacers in the case of their «extended» conformation is approximately the same for the considered bis-surfactants and allows two hydrocarbon molecules to be vertically introduced into the resulting cavity. The «compact» conformation of flexible spacers ensures the implementation of intramolecular CH‧‧‧HC interactions between hydrocarbon chains, which are not carried out in monomers with «extended» one. The thermodynamic parameters of formation for the found monomer conformations are calculated. For gemini surfactant conformers, the formation of structures with a «compact» spacer is more advantageous according to the Gibbs energy due to the formation of intramolecular CH‧‧‧HC interactions between hydrophobic chains of the amphiphilic compound. Comparison of the contributions of intramolecular CH‧‧‧HC interactions to the formation enthalpy and entropy of bis-surfactants with an etoxylated bridge in a «compact» conformation reveals good agreement with the similar contributions of intermolecular ones for dioxyethylated alcohols. It shows the same nature of CH‧‧‧HC interactionns realizing both inside a molecule with two hydrocarbon chains and between two surfactant molecules with single hydrocarbon chain.
Keywords: gemini surfactants, monomer, enthalpy, absolute entropy, Gibbs energy of formation, CH‧‧‧HC interactions.

Klychkov N.A., Kurmasheva D.V., Simakov V.V., Sinev I.V.
Mathematical modeling the polycrystalline layers conductivity of wide-bandgap semiconductors during adsorption on their surface of gases-reducers in the presence of oxygen – page 424
Abstract: The results of the response study of gas sensors based on gas-sensitive layers Cu:SnO₂ toethanol, acetone, and  2-propanol vapors is are presented. Sensor response concentration dependencies are measured at different temperatures to determine optimal operating modes. Experimental temperature dependence of the sensors response to the vapors of the analyzed substances are determined. The dependence is theoretically substantiated by a proposed mathematical model based on consideration of the processes of transfer of charge carriers through the potential barrier grains of a polycrystalline semiconductor film in an oxygen-containing medium and the reducing gas to be analyzed. It is assumed that each type of gas on the surface of SnO₂ has its own adsorption centers. The work shows that the model can be used to calculate and predict the gas sensitivity measurements of sensors based on the active layers of polycrystalline semiconductors. The results of the calculations confirm that such energy parameters as the depth of the energy level and the desorption energies are individual for each substance.
Keywords: organic matter vapor detection, semiconductor gas sensor, tin dioxide, temperature response dependency, dissociative adsorption.

Kolosov A.Yu., Savina K.G., Veresov S.A., Serov S.V., Sokolov D.N., Sdobnyakov N.Yu.
Scenarios of structure formation in four-component nanoparticles: atomistic simulation – page 432
Abstract: Scenarios of structure formation in four-component nanoparticles are considered. The objects of study were Au-Cu-Pd-Pt nanoparticles containing N = 400, 800, 1200, 1600, 2000, 4000 atoms of the stoichiometric composition Au₃CuPd₁₂Pt₄. Two alternative modeling methods were used: the molecular dynamics and the Monte Carlo. The interaction between atoms was described by the tight binding potential. The phase transition temperatures for the nanoparticles under study were determined. It has been established that the melting and crystallization temperatures depend both on the size of nanoparticles and on the rate of temperature change (by using the molecular dynamics method). The melting rate of nanoparticles has little effect on the melting temperature, while increasing the cooling rate significantly reduces the crystallization temperature and slows down the segregation processes. The process of coalescence of two four-component nanoparticles was modeled. During the process of coalescence, significant mixing of atoms of different types does not occur when using the Monte Carlo method, which leads to some stopping of the growth of the neck at the point of contact, in contrast to molecular dynamics method, where the growth of the neck occurs gradually.
Keywords: molecular dynamics method, Monte Carlo method, tight-binding potential, four-component nanoparticles, structure formation, melting and crystallization temperatures.

Komarov P.V., Malyshev M.D.
Study of the effect of the ratio of epoxy resin and curing agent comonomers on mechanical properties of the system: mesoscale simulation – page 444
Abstract: This publication continues the cycle of our work aimed at improving the methodology for constructing mesoscale models of network polymers and characterizing their physical properties. As the object of study, the epoxy resin of bisphenol A, diglycidyl ether, and a tricarboxylic fatty acid hardener was chosen. Its structure is the result of three parallel reactions. For their correct reproduction, an algorithm was proposed, which allows to take into account the peculiarities of the relationship of all ongoing processes. The system model was constructed by mapping the chemical structure of the monomers onto an equivalent mesoscale representation. It was used to study the relationship between the structure and mechanical properties of feeding networks as a function of the ratio of volume fractions of comonomers in the initial reaction mixture. All calculations were performed within the reaction version of the dissipative particle dynamics method. The structure of polymer networks in the constructed samples was characterized by topological analysis. The study of mechanical properties was carried out by constructing the “stress-strain” dependencies. The results obtained show a good correlation between the density of the load-bearing chains and the mechanical properties of the resulting networks. It is shown that the material samples with the highest degree of transformation and the density of the number of load-bearing chains have the highest stiffness.
Keywords: network polymers, mesoscopic simulation, dissipative particle dynamics, mechanical properties.

Kotomkin A.V., Orlov Yu.D.
Quantum-mechanical calculation of the structural and energetic characteristics of the fluorinealcanes – page 456
Abstract: Within the «quantum theory of atoms in molecules» the charge q and volume V of topological atoms A and atomic groups R of fluorinated molecules of ethanes C2H_mF_k, where 0 ≤ m, k ≤ 6 and m+k = 6 and propanes C₃H_mF_k, where 0 ≤ m, k ≤ 8, m+k = 8, has been calculated by Aimall software package. Optimization of the geometry and finding of the electron density distribution (ρ(r)) has been carried out by the GAUSSIAN 03 program with the B3LYP 6-311++G (3df,3pd) 6d 10f level of theory. Influence of fluorine atoms on near atomic groups has been studied. The absence of the transferable functional groups has been showed. A conclusion has been made about unsuitability of the evaluation of properties by additive methods, which do not consider differences in electron structures for this class of compounds. The enthalpy of formation ΔfH⁰ of 38 molecules of fluorethanes and fluorpropanes has been computed by the G4 method. The comparison with the experimental values has shown good coherence. Results of this work is planned to be used in designing additive models for prediction of thermodynamic and thermochemical properties of organic fluorinated compounds.
Keywords: inductive effect, electronegativity, electron structure, enthalpy of formation, quantum theory of atoms in molecules, electron density, fluorine alkanes, fluorethanes, fluorpropanes.

Kuznetsov Yu.A., Lapushkin M.N.
Ge adsorption on W(100): calculations – page 465
Abstract: For the first time, the adsorption of germanium atoms on the (100) face of tungsten was calculated using the density functional theory. The tungsten substrate was made as a 2D layer. The W2D layer was modeled by a W(100) 2×2×2 supercell. The calculation of the electron density of state and the adsorption energy of a Ge atom was carried out for three adsorption sites of the Ge atom: in the hollow position, in the bridge position between surface W atoms, and above the surface W atom: one Ge atom per 8 surface W atoms (most preferably adsorption of a germanium atom in hollow position). The adsorption energy is significant: 6,38 eV. The adsorption of Ge atoms leads to an insignificant reconstruction of the W surface: the maximum shift of W atoms does not exceed 0,15 Å. The valence band of the W(100) 2D layer is formed mainly by W 5d electrons, with an insignificant contribution of W 6s electrons. The Ge band is formed by Ge 4p electrons and Ge 4s electrons.
Keywords: adsorption, electronic structure, interface, germanium, tungsten.

Kurbanova E.D., Belyakova R.M., Polukhin V.A.
Micro and nanosized materials with high entropy – page 472
Abstract: The stability of high-entropy alloys, like equiatomic and non-equiatomic micro- and nanostructural ones, is relevant when creating stable multicomponent compositions with improved performance. The implementation of such materials is possible by mechanical alloying, magnetron sputtering, as well as by the electrochemical method using the «top-down and bottom-to-top» strategy at moderate temperatures < 200°C with controlled production of both micro-from 0,5 to 20 μm and nanoscale high-entropy alloys with particles from 2 to 10 nm. The well-studied «structure-property» relationship for classical alloys is not yet completely clear for nano-high-entropy alloys, but it is obvious that it is possible to form excellent mechanical characteristics by selecting chemical compositions and a special heat treatment regime. Regarding the chemical composition, requirements are imposed both on the main components and alloying additives. Preliminarily, not only compositions are selected, but also methods for the synthesis of high-entropy alloys, including ab initio (density functional theory), neural network prediction, and classical molecular dynamic simulation with possible conditions for the formation of model nano- high-entropy alloy samples, as well as derivative options. The resulting descriptions are compared with real methods of high-entropy alloys synthesis, for example, exposure to various synthetic media.
Keywords: multicomponent, amorphous and nanocrystalline alloys, high-entropy alloys, nano- highentropy alloys, strain hardening, landscape-local fluctuations, strength, thermal stability, layered composites, thermodynamic calculations.

Malysheva N.E., Dyakova E.V., Malyshkina O.V.
Simulation of the dielectric response of piezoelectric ceramics – page 481
Abstract: We have analyzed the complex permittivity of a porous (10 volume % of pores) sodiumlithium niobate ceramic with the results of computer simulation. The calculation was based on the Cole–Cole formula, which took into account the presence of various mechanisms of relaxation processes in the low-frequency (linear dispersion) and mid-frequency regions, an additional term from the Debye formula was added to take into account the mixed polarization, and a term taking into account the damping factor was added for resonant-type polarization. The simulation was carried out with and without the conductivity taken into account. To take into account the contribution of conductivity to the dynamic dielectric response, the expression σ* = (ε″ + iε′)ε0ω was used. It is shown that the linear part of the frequency dependence in the range from 50 Hz to 1 MHz is equally well described both with and without conductivity. At the same time, the behavior of the dielectric response of piezoelectric ceramics in the high-frequency region, where resonance effects are observed, and the low-frequency region, where volume-charge polarization predominates, is much better described taking into account the contribution of conductivity to the dielectric response of the system.
Keywords: piezoelectric ceramics, complex permittivity, complex conductivity, dielectric spectroscopy.

Myasnichenko V.S., Ershov P.M., Veresov S.A., Bazulev A.N., Sdobnyakov N.Yu.
Size effect and structural transformations in ternary nanoparticles Ti_x^–Al_96-x^–V₄ – page 495
Abstract: The final configurations obtained during crystallization in ternary metal nanoalloys Ti_x^–Al_96-x^–V₄ of various compositions were studied. The molecular dynamics method was used as an atomistic simulation method. Interatomic interaction was described by the tight-binding potential. The size dependence of melting temperatures, as well as changes in melting and crystallization temperatures with changes in the composition of ternary nanoparticles, have been determined. Based on the results of a series of computer experiments, differences in the crystallization scenarios of Ti_x^–Al_96-x^–V₄ ternary nanoparticles were established. A classification based on internal structure and degree of crystallinity was proposed and tested. For Ti_x^–Al_96-x^–V₄ ternary nanoparticles, five main classes are identified based on the number of (semi) axes of 5th order symmetry. Despite the fact that studying the segregation of components of Ti_x^–Al_96-x^–V₄ ternary nanoparticles was not the goal of the work, atomic configurations corresponding to different temperatures during the cooling process were constructed and described.
Keywords: molecular dynamics method, tight-binding potential, ternary nanoparticles, structure formation, melting and crystallization temperatures.

Nepsha N.I., Sokolov D.N., Mitinev E.S., Taktarov A.A., Sdobnyakov N.Yu.
Scenarios of structure formation in ternar nanoparticles based on Pd-Pt in the presence of Ni dopant – page 507
Abstract: In this work, scenarios of structure formation in ternary nanoparticles based on platinum and palladium of four stoichiometric compositions of different sizes were studied, with nickel acting as a dopant. Two alternative methods were used: the molecular dynamics method (implemented in the open source software LAMMPS) and the Monte Carlo method (implemented in the Metropolis scheme). In addition, to describe the interatomic interaction, two versions of force fields were used: the modified tightbinding potential (when implementing the molecular dynamics and Monte Carlo methods) and the embedded atom potential (when implementing the molecular dynamics method). Based on the results of a series of computer experiments, it was found that palladium atoms have increased segregation to the surface. At a cooling rate of 0,1 K/ps, an ordered crystalline FCC structure with inclusions of the HCP phase is formed. With an increase in the nickel dopant content to 20% in the ternary Pd-Pt-Ni nanoparticle, the identifiable local structure becomes more complex, both in terms of the number of phases and in terms of structural segregation.
Keywords: molecular dynamics method, Monte Carlo method, embedded atom potential, modified tightbinding potential, polyhedral template matching method, bimetallic and ternary nanoparticles, nickel, palladium, platinum, structure formation, melting and crystallization temperatures.

Polukhin V.A., Estemirova S. Kh., Kurbanova E.D., Belyakova R.M.
Nanosized high-entropic materials based on HEA, design principles and synthesis methods – page 520
Abstract: The principles of designing high-entropy alloys related to the selection of elements areanalyzed. When selecting elements, a parametric approach is used, including chemical and topological parameters. The main chemical parameter is the enthalpy of mixing of elements, the main topological parameter is the atomic radius. It is emphasized that the use of modified atomic radii (which take into account the local electronic environment) better predicts the formation of either amorphous or crystalline high-entropy alloys. Four main effects that determine the properties of high-entropy alloys are considered: the high entropy effect, the lattice distortion effect, the delayed diffusion effect, and the «cocktail» effect. Obtaining nanosized high-entropy materials based on high-entropy alloys is a new promising direction that allows one to significantly expand their areas of application related to energy (catalysis, energy storage, etc.), nanoelectronics, etc. The article analyzes some methods for the synthesis of nanosized high-entropy alloys and materials based on them. basis, developed as catalysts. The improved performance over conventional catalysts is explained in terms of the effects and features specific to multicomponent systems.
Keywords: multicomponent, amorphous and nanocrystalline alloys, high-entropy alloys and nanosized high-entropy alloys, morphology, catalysts, fcc and hcp structures, bcc, strength, thermal stability.

Ryzhkova D.A.
Phase-change memory cells based on nanoparticles alloy Ag-Au – page 536
Abstract: Phase-change random access memory is an excellent candidate for next-generation nonvolatile memory technology. In order to meet the needs of the industry, its capacity must be improved, for which it is necessary to reduce the volume of a unit cell. Proceeding from this, in this work, the possibility of using nanoparticles of the Ag-Au binary alloy as individual phase-change random access memory cells was evaluated by computer simulation. The method of molecular dynamics with a modified tight binding potential was used. For this, an analysis was made of the crystallization processes of these nanoparticles with a diameter of 2,0 to 8,0 nm with different rates of thermal energy removal. It was shown that the addition of gold to the composition makes it possible to solve the problem of the complex reproduction of the amorphous structure, which is characteristic of pure Ag nanoparticles. Due to this, stable switching between the amorphous and crystalline phases can be achieved at a nanocluster diameter of ≥4 nm and ≥6 nm with an Au content in the composition of ≥40% and ≥20%, respectively, which is significantly lower than the cut-off value of 10 nm characteristic of silver nanoparticles.
Keywords: nanoclusters, silver, gold, crystallization, structure, computer simulation, tight-binding, PCM cell.

Savina K.G., Grigoryev R.E., Veselov A.D., Bogdanov S.S., Ershov P.M., Veresov S.A., Zorin D.R., Myasnichenko V.S., Sdobnyakov N.Yu.
The problem of obtaining crystaline phases during cooling binary nanoparticles Au-Co and Ti-V – page 543
Abstract: The processes of structure formation in Co-Au and Ti-V metal nanoparticles as well as factors affecting the crystallization process are considered. The objects of the study were Co-Au and Ti-V binary nanoparticles containing N = 400, 800, 1520 and 5000 atoms with the equiatomic composition. The computer experiment was carried out using method of molecular dynamics. The interatomic interaction was described by the tight-binding potential. According to the results of a series of computer experiments, it was found that the main factors influencing the possibility of obtaining crystalline phases are: the cooling rate of binary nanoparticles, their size and the size mismatch of atoms included in the composition, as well as the nature of the interaction of metal atoms. The manifestation of stability/instability in binary nanoparticles may be due to patterns of formation of crystalline phases. Moreover, the tendency to segregate one of the components in a binary system may not be the main factor determining the stability/instability of such a system.
Keywords: molecular dynamics method, tight binding potential, binary nanoparticles, cobalt, gold, titanium, vanadium, dimensional mismatch, crystallization.

Samsonov V.M., Talyzin I.V., Vasilyev S.A., Puitov V.V.
Surface melting in nanoparticles and nanosystems. 1. Regularities and mechanisms of surface melting of macroscopic phases and nanoparticles – page 554
Abstract: Being the first part of a two-part series, published in this issue of the journal, this paper combines a brief overview of theoretical and experimental studies, as well as the results of atomistic simulations of surface melting in bulk bodies and nanoparticles with presentation of our own molecular dynamics results. We have studied the patterns and mechanisms of surface melting in metal nanoparticles (gold, silver, copper, lead and nickel). The patterns and mechanisms of this phenomenon were studied in most detail on gold and silver nanoparticles. It has been established that the effect of surface premelting is characteristic for nanoparticles of all the above metals, although with decreasing particle size this effect manifests itself to a lesser extent. In addition, our molecular dynamics results do not confirm theoretical predictions of some authors about the existence of a quite definite characteristic (critical) radius of nanoparticles, below which the effect of surface melting is completely absent.
Keywords: surface melting (premelting), metal nanoparticles, molecular dynamics, embedded atom method, LAMMPS.

Samsonov V.M., Vasilyev S.A., Talyzin I.V., Puitov V.V.
Surface melting in nanoparticles and nanosystems. 2. Scientific and nanotechnological aspects of the role of surface melting in nanoparticles and nanosystems – page 571
Abstract: Taking into account results of our molecular dynamics experiments, we have concluded thatof the three  commonly considered alternative models of nanoparticle melting (homogeneous melting, liquid shell, nucleation of liquid and growth), the latter is the most adequate. At the same time, a more adequate model corresponds to a combination of continuous melting at the initial stage of the process with its subsequent abrupt completion. In other words, nucleation and growth of a liquid-like surface layer occur until a certain critical radius of the crystalline core of the particle is reached, and then melting is completed very quickly, almost abruptly (in fractions of a nanosecond) at a temperature interpreted as the nanoparticle melting temperature T_m. Then, the role of surface melting in nanoparticle sintering is discussed. According to our results, the sintering of metal nanoparticles at high temperatures cannot be reduced to a single mechanism: a certain role play surface melting, surface and bulk diffusion, deformation in the contact zone, and collective effects associated with the displacements of groups (clusters) of atoms rather than of individual atoms. We also have put forward and substantiated the hypothesis that the previously introduced redetermined Tamman temperature T_T=0,5T_m corresponds to the switching of the scenario of sintering of metal nanoparticles from formation of a dumbbell-shaped nanocrystal at low temperatures to the scenario corresponding to coalescence of solid nanoparticles resulting in the formation of a defective nanocrystal of a shape close to spherical.
Keywords: surface melting, metal nanoparticles, melting mechanisms, coalescence and sintering, molecular dynamics, thermodynamics.

Sdobnyakov N.Yu., Kolosov A.Yu., Sokolov D.N., Savina K.G., Bazulev A.N., Veresov S.A., Serov S.V.
Complex approach to the simulation of melting and crystallization in five-component metallic nanoparticles: molecular dynamics and the Monte Carlo method – page 589
Abstract: The melting and crystallization phase transitions in the five-component metallic Au-Ag-Cu-Pd-Pt equiatomic nanosystem were investigated. The complex approach to atomistic modeling is due to the use of alternative methods of computer simulation – the molecular dynamics and Monte Carlo methods. The interatomic interactions were described by the tight-binding potential. According to the results of a series of computer experiments, it was established that five-component nanoparticles of equiatomic composition can form crystalline phases during cooling. Melting and crystallization temperatures for the investigated five-component nanoparticles were determined. The values obtained by alternative methods are in good agreement. For five-component nanoparticles, the concept of fixing the temperatures corresponding to the beginning and end of the phase transition process is confirmed. The metals that make up five-component nanoparticles, the atoms of which in the process of crystallization form the central part of the nanoparticle (core) and the peripheral regions, including the surface of the nanoparticle, are determined.
Keywords: molecular dynamics method, Monte Carlo method, tight binding potential, five-component nanoparticles, structure formation, melting point, crystallization temperature.

Sokolov D.N., Polev O.V., Myasnichenko V.S., Savina K.G., Sdobnyakov N.Yu.
On the structural stability of mono- and binary metallic nanocages – page 602
Abstract: This work is devoted to the problem of thermal stability of mono- and binary metal nanocages consisting of gold and silver atoms. The number of atoms in the studied nanocages was 1744, 2150, 2470 and 3370 atoms. The characteristic size (outer diameter) of nanocages is from 4,4 to 5,1 nm. Interatomic interaction was described by the tight-binding potential. Analysis of the caloric dependences of the specific potential part of the internal energy made it possible to identify the temperature regions of «healing» of cavities (pores) on the faces and in the internal regions (cores) of nanocages. An example of the structural collapse of a nanocage is described in detail, as a result of which crystalline and quasicrystalline phases are identified in the nanoparticle core for a temperature corresponding to melting for the chosen size. Segregation in a binary Au-Ag nanocage before and after its collapse was also studied.
Keywords: atomistic simulation, tight binding potential, metallic nanocages, porеs, thermal effects, stability/instability, structure formation.

Cherepovskaya A.A., Ryzhkova D.A.
Computer simulation of structuring Ag-Cu nanoparticles – page 614
Abstract: In this work, computer simulation of the processes of formation of the internal structure of plasmonic Ag-Cu nanoparticles was carried out. Method of molecular dynamics based on the tight binding potential was used. The crystallization of Ag-Cu nanoparticles with a diameter of 2,0-8,0 nm with an atomic copper content ranging from 10 to 50% was simulated. To remove thermal energy, an Andersen thermostat was used with three different cooling rates ΔT/Δt = 30∙10¹¹, 12∙10¹¹, 5∙10¹¹ K/s. The possible structural transitions arising in this case were determined using the radial distribution function and the change in potential energy. To determine the most stable cluster structure, an ensemble of nanoparticles of the same size was taken. Then, using the visualizers OVITO and xmakemol, the real appearance and structure of the studied nanoparticles were found. In the course of the simulation, it was found that at low levels of copper doping in Ag-Cu nanoparticles, the formation of five-particle symmetry is possible. The conditions for the occurrence of this effect were fixed. It was also determined that D = 8,0 nm for Ag-Cu nanoparticles is the size limit, starting from which the macroscopic effect of stabilizing the fcc structure of the eutectic alloy appears under the condition of very fast sample quenching.
Keywords: nanoclusters, silver, copper, crystallization, structure, computer simulation, tight binding.

4. PHYSICAL AND CHEMICAL BASES OF NANOTECHNOLOGIES – page 622

Ataeva A.Yu.
Dependence of the displacement of nanoparticles on channels in a jet bubbler – page 622
Abstract: The work is devoted to an experimental study of the behavior of bubbles when capturing pulverized materials with nanoparticles in the course of colliding of gas-liquid jets in a bubbling layer. The article discusses the use of channels in a jet bubbler and the dependence for detecting horizontal movement of bubbles with nanoparticles in them. The purpose of this stage of research is to study the behavior of gas-liquid jets when exiting without a guide channel and through a guide channel. The results of experiments conducted on the patented design of the jet bubbler are analyzed. The article presents the results of experiments conducted to study the shapes and sizes of formed gas bubbles. The graphs constructed after processing the frames of the kinogram according to the data of the experiments are given. On the basis of preliminary tests, the features of using channels to create the jet collisions in an experimental setup to increase the range of captured solid particles, including nanoparticles, are substantiated.
Keywords: ecosystem, dust and gas separator, nanoparticles, channel, wet dust collection, bubbling.

Belov A.N., Vostrov N.V., Pestov G.N., Solnyshkin A.V.
Features of the formation of an array of isolated polymer P(VDF-TrFE) nanoparticles in pores of a periodic nanostructured silicon oxide membrane – page 629
Abstract: This work is devoted to the technological features of creating an array of pyroelectric nanoparticles placed in the pores of a silicon oxide membrane, ensuring their thermal insulation both from each other and from the supporting substrate. Mechanisms of anodic oxidation of the Al/Ti/SiO₂ structure, ensuring the self-organization of a nanostructured oxide mask with specified geometric parameters, have been established. It has been shown that from a certain thickness of the adhesion layer, overgrowing of the open areas of the mask with titanium oxide nanoparticles does not occur. The regularities of the method of local ion etching of multilayer structures are determined, which ensures control of the depth of the formed pores by controlling the ion current. A correlation has been established between the lateral size of the cavities in silicon and the aspect ratio of aluminum oxide pores. The possibility of forming a silicon oxide membrane with pyroelectric polymer nanoparticles embedded in its pores has been demonstrated.
Keywords: polymeric ferroelectric, porous silicon oxide, ion-beam etching, IR – photodetector ,porous anodic alumina, micromembrane, anisotropic etching.

Belov A.N., Vostrov N.V., Pestov G.N., Solnyshkin A.V.
Planar jet printing of localized Ni/P(VDF-TrFE)/Ni structures for piezo- and pyroelectric matrixes – page 637
Abstract: This paper describes manufacturing the film structures based on a polar copolymer of poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE) using the process of drop-by-drop local deposition on metallized substrates. The produced samples were a crossbar structures of arrays of ferroelectric P(VDF-TrFE) microislands metallized with nickel stripes using a combined 2D printing method. For the polymer layer deposition, a number of solvents with different viscosities and dipole moments of molecules were considered, and their influence on the geometry and the polar properties of printed layers was shown. Using the piezoelectric force microscopy, the value of the piezoelectric modulus of d₃₃ at the nanoscale level was determined. This d₃₃ modulus is similar to values of d₃₃ for P(VDF-TrFE) films produced by the standard solvent cast method. On the base of amplitude of the pyroelectric current in the dynamic method, the value of the pyroelectric coefficient (p) was determined, varying from 2⋅10^–5 to 4⋅10^–5 C/(m²⋅K). These values are comparable to the pyroelectric coefficient of films P (VDF-TrFE) produced by the standard method. The highest values of d₃₃ and p correspond to structures produced from solutions containing more than 20% of propylene carbonate in the initial solvent, the molecules of which have a large (4,9 D) dipole moment.
Keywords: .

Bogdanova E.A., Skachkov V.M.
Study of the possibility of obtaining biocomosites based on nanoscale hydroxyapatite with metals and biogenic elements – page 649
Abstract: The article discusses the possibility of obtaining a hardened composite material with a porous structure based on nanostructured hydroxyapatite (HAP) synthesized by precipitation from a solution. The new material by the mechanochemical synthesis of hydroxyapatite with aluminum, silicon, nickel, hafnium and titanium was obtained. The synthesized samples are certified using modern physico-chemical methods of analysis. The influence of the qualitative and quantitative composition of the composite on the sintering processes and the strength characteristics of the studied samples is shown. It has been experimentally established that the system Ca₁₀(PO₄)₆(OH)₂ – Ti is the most promising for the development of biocomposites based on it. Composite materials of this composition with the content of the doping component (10-20 wt.%), have a dense uniform structure with a high degree of crystallinity, with developed porosity, are a promising material for further research in order to introduce it into medical practice. A patent application has been filed for the developed composite material.
Keywords: hydroxyapatite, titanium, sintering, composite biomaterials, crystallinity, microhardness.

Bogdanova E.A., Khonina T.G., Sabirzyanov N.A.
Investigation of transport properties hydroxyapatite and its derivatives – page 659
Abstract: The article discusses the possibility of practical application of hydroxyapatite and fluorapatite as components of medicines, pharmaceutical compositions and biomaterials, the use of which is based on the transdermal delivery route of the active substance. The viscosity, density, degree of dispersion and transport properties (transmucose permeability) of hydroxyapatite and fluorapatite were estimated using modern physicochemical methods of analysis. Particular attention is paid to the joint use of the studied substances and silicon glycerolates as a conductor with pronounced transcutaneous, penetrating properties, contributing to the accumulation of locally applied drugs in biological membranes (skin, mucosa, etc.) without disturbing its structure. It is shown that the transport properties that determine the effectiveness of the action depend on the physico-chemical characteristics of the substances being penetrated. Diffusion transfer and the ability to control the processes taking place can be used for optimal design of drugs for targeted delivery through the skin and mucous membranes.
Keywords: hydroxyapatite, fluorsubstituted hydroxyapatite; siliconglycerolatas; transmucosal permeability.

Bolotov A.N., Novikova O.O.
Experimental study of the fluidity of nanostructured magnetic fluid in a strong magnetic field – page 670
Abstract: In this paper, we studied the changes in the topography of the surface of a unit made of magnetostrictive magnetoplast under the influence of a magnetic field. Theoretical analysis has shown that in composite materials when using magnetostrictive particles with a dispersion of 10^-4÷10^-6 m, a change in the surface roughness parameters is possible in the range of 10^-7÷10^-9 m, depending on the magnetostrictive constants of the filler. Local changes in the topography of the magnetoplast surface in a magnetic field with a strength of about 560 kA/m are experimentally determined, and an assessment is made of the integral changes characterizing the surface as a whole. For the experiment, a composite material containing a powder of TeFe₂ material with a uniquely high linear magnetostriction (λ_s = 2∙10³) was chosen. It has been established that the effect of the surface nanoroughness changing is especially pronounced for relatively smooth surfaces and depends on the composition, concentration, size, and orientation of the microfine magnetic filler. For the studied surfaces of magnetoplasts, the change in the height parameters of roughness exceeds 5%. In absolute terms, the change in the topography of the surface is tens of nanometers. In precision engineering, the detected effect can be used to control frictional characteristics, in particular, to change the friction force without contact, control the flow of small doses of various reactive gases, and change the dynamics of wetting processes of solid surfaces.
Keywords: magnetostriction, magnetoplast, magnetic field, surface topography, surface roughness, composite material.

Bolotov A.N., Afanasieva L.E., Meshkov V.V.
Lubricant properties of nanodisperse magnetic oils based on novel technical liquids – page 679
Abstract: The paper presents the results of studying properties of magnetic lubricating oils synthesized on the basis of fluoroorganic fluids and triethanol. The lubricating properties of oils were determined in the boundary friction mode under medium and high contact pressures. It is shown that magnetic oils based on perfluoropolyether have higher lubricating properties than oils based on other fluids, especially in the medium load range. The anti-wear properties and aggregative stability of oil begin to deteriorate sharply at temperatures exceeding 150°С. The use of perfluoropolyether liquid as an additive to oil made it possible to improve the antiwear properties of magnetic oil at medium and high contact pressures. The lubricating properties of magnetic oils based on triethanolamine are approximately the same as those of magnetic oils based on siloxanes, but worse than those of traditional non-magnetic oils. In terms of tribological properties, the studied magnetic oils are comparable to traditional plastic and liquid lubricants. The fact that magnetic oils have magnetic properties that are anomalous for liquids expands the area of their effective application significantly.
Keywords: magnetic lubricating oil, fluoroorganic liquids, triethanolamine, nanodisperse particles, friction, wear.

Bolotov A.N., Novikova O.O.
Experimental study of the fluidity of nanostructured magnetic fluid in a strong magnetic field – page 692
Abstract: Based on magnetic fluids, new effective technical devices have been implemented, such as magnetic fluid bearings, seals, and dampers. The magnetic-viscous effect inherent to magnetic fluids can not only improve the properties of magnetic fluid units, but significantly complicate their operation after a long stop. This refers to the so-called «stop effect», which occurs due to an abnormally high limiting shear stress in a nanostructured liquid. The plastic properties of the magnetic fluid are experimentally studied depending on the following parameters: shear stress, temperature, structure formation time. The destruction of the nanostructure of the magnetic fluid begins after the shear stress exceeds a certain critical value. At stresses below the critical, but above the limiting shear stress, the displacement of the solid surface occurs by overcoming the boundary friction of the magnetic fluid on the solid surface. The experimentally established exponential course of the temperature dependence of the shear rate reflects the nature of the forces that determine the internal friction in the magnetic fluid.
Keywords: magnetic fluid, yield strength, nanodispersed particles, magnetic interaction, chain model.

Gorshkov A.I., Gribanov E.N.
Features of the mechanism of formation of morphology of aluminosilicate films on aluminum substrate – page 701
Abstract: The features of the formation of morphology of thin aluminosilicate films obtained electrochemically on an aluminum substrate from aqueous solutions of sodium silicate and sodium hydroxide have been systematically studied by atomic force microscopy. The effect of stress on the shape and characteristic dimensions of the surface elements of aluminosilicate films is shown. Films synthesized at a lower voltage (8 V) are characterized by an amorphous surface consisting of globules whose size ranges from 500 nm to 2,5 microns, for samples obtained at a higher voltage (more than 16 V), parallelepipeds with linear dimensions of 150-250 nm act as are found to be structural elements. It is established that at the first stage of synthesis, the surface of the aluminum anode is etched, and the resulting cells act as pores in which the aluminosilicate phase is formed. An assumption is made about the formation of films along the path of autocatalytic nucleation and about a direct dependence of the rate of formation of the crystalline phase on the voltage at which the synthesis is carried out.
Keywords: synthetic aluminosilicates, growth mechanism, thin films, surface morphology, electrochemical synthesis.

Doroshenko A.E., Krut’ko V.K., Musskaya O.N., Dovnar A.I., Ostrowskaya O.B., Doroshenko Ye.M., Kulak A.I.
Phase composition and biocompatibility of calcium phosphate coatings on titanium enriched with hydroxyapatite – page 708
Abstract: Calcium phosphate coatings containing brushite, calcite, and apatite were obtained by electrochemical deposition on titanium plates at room temperature, pH 5, constant current density 30 mA/cm², from CaCO₃/Ca(H₂PO₄)₂ suspension electrolyte. A layer of amorphous apatite was deposited by the biomimetic method, by keeping the coatings in a concentrated modeling solution of Simulated Body Fluid. As a result of heat treatment at 800°C, apatite crystallized into hydroxyapatite, calcite decomposed to calcium oxide, and titanium was covered with a layer of titanium (IV) oxide. Preclinical studies on rats in vivo for 3 months showed increased osseointegration of plates with calcium phosphate coatings compared to uncoated titanium. Titanium implants with calcium phosphate coatings enriched with hydroxyapatite are promising for use in neurosurgery, dentistry, orthopedics due to the absence of inflammatory reactions from the body and increased osseointegration.
Keywords: calcium phosphate coatings, brushite, calcite, SBF model solution, apatite, hydroxyapatite.

Zajogin A.P., Trinh N.H., Patapovich M.P.
Influence of the defocusing parameter of dual laser pulses on the possibility of designing thin-film cassensitive sensors – page 718
Abstract: The possibility was studied of creating thin-film gas-sensitive sensors using composite materials containing tin in their composition, which can significantly improve their characteristic. In addition, a layer-by-layer analysis of metals and multicomponent alloys was carried out under the action of dual laser pulses on a target in an air atmosphere. All experiments were carried out using a laser two-pulses multichannel atomic emission spectrometer LSS-1. In the course of this study, the processes of formation of a certain component composition of the near-surface laser plasma, as well as the influence of the defocusing parameter between doubled laser pulses upon their impact on the surface of the irradiated sample, were studied. Thus, this work illustrated the development of methods for obtaining nanoclusters of chemical elements during spectroscopic studies of laser plasma formed by the action of two successive pulses on a target and the possibility of obtaining nanofilms of both pure metals and composite alloys for subsequent practical application.
Keywords: gas-sensitive sensors, double laser pulses, laser plasma, layer-by-layer analysis, deposition of thin films, multichannel atomic emission spectrometry..

Ivanov Yu.F., Klopotov A.A., Shugurov V.V., Azhazha I.I., Petrikova E.A., Tolkachev O.S., Nikonenko A.V.
Amorphous-crystalline boron-containing coatings formed by the ion-plasma – page 725
Abstract: Using the method of high-frequency ion-plasma sputtering (magnetron highfrequency deposition under conditions of ion-plasma assisted using a gas (argon) plasma generator «PINK») on the surface of a high-entropy CoFeCrMnNi alloy of non-equiatomic composition. Boron-containing coatings of the elemental composition Al – Mg – B and Mg – Ti – B with a thickness of 3 μm are formed. Using transmission electron diffraction microscopy, it was found that the coatings are amorphous-crystalline, i.e. contain nanosized 1.5-2 nm islands of the crystalline phase located in an amorphous matrix. It is shown that the coating deposition is accompanied by the formation in the substrate layer (high-entropy alloy) adjacent to the coating of a nanocrystalline structure with a crystallite size of 25-40 nm. At the boundaries of the crystallites, particles of iron boride of the FeB and Fe₃B compositions are revealed, which indicate the penetration of boron into the substrate. The particle size of iron boride is 5-8 nm.
Keywords: ion-plasma method, high-entropy alloy, film/substrate systems, boron-containing coating, structure, mechanical and tribological properties.

Kislova I.L., Malyshkina O.V., Ivanova P.A., Ivanova A.I.
Production of barium-calcium-strontium niobate ceramics with optimal properties for practical application – page 736
Abstract: In this work, we obtained at various sintering temperatures and studied the ceramic samples of a 3-component system of barium niobate – calcium – strontium (Ca_0,28Ba_0,72)_0,25(Sr_0,61Ba_0,39)_0,75Nb₂O₆ (CSBN25) which is a nanostructured solid solution. The effect of sintering temperature on the structure and dielectric properties of CSBN25 ceramics was studied. It has been established that the CSBN25 sample obtained at a sintering temperature of 1300°С has the optimal ferroelectric properties. For this sample, the pore size does not exceed 10 – 100 nm, while for samples sintered at other temperatures, pores can reach 10 microns. Using examples of CSBN25 ceramics, we have also shown a direct relationship between the uniformity of the grain structure and their packing density with the dielectric properties of the samples: the maximum density and the value of the permittivity have the samples that have a dense, uniform grain structure not only on the surface, but also in the bulk of the samples. Increasing the sintering temperature of CSBN25 ceramics to1350°С leads to the appearance of an amorphous state in the sample bulk and, as a result, to a decrease in the dielectric constant.
Keywords: piezoelectric ceramics, barium – calcium – strontium niobate, lead-free materials, grain structure, permittivity.

Klychkov N.A., Simakov V.V., Efanova V.V., Sinev I.V.
Cross effect of isopropanol and ethanol vapor on the response of a semiconductor gas sensor – page 746
Abstract: the temperature dependencies of the response of Cu:SnO₂ films to ethanol, 2-propanol vapours, as well as ethanol with 3% vol. background impurities of 2-prophanol in the working temperature range of 250-375°C. The aim of the study was to determine the effect of the 2-propanol background impurities on the sensor response to ethanol, as well as to assess the possibility of distinguishing a steam-air mixture containing pure ethanol vapors from a gas mixture of ethanol/2-propanole by means of single-sensor signal statistical processing. The temperature dependencies analysis of the sensor response showed that the temperature at which the maximum response is observed is individual for each substance. A selective response to substances was detected. It was found that the 3% vol. isopropyl alcohol compound decreases the response to ethanol in the tested concentration and temperature range. Statistical processing of experimental data by the principal component analysis (PCA) and cross-validation of the model by the ellipsoid and nearest-neighbor showed the fundamental ability to recognize ethanol, 2-propanol and their mixture.
Keywords: semiconductor gas sensor, detection of gas mixture, tin dioxide, temperature dependence of response, principal component analysis.

Malashenko V.V., Malashenko T.I.
Effect of nanoscale defects on inelastic processes in aged alloys – page 754
Abstract: The high strain rate deformation of an aged alloy with a high concentration of GuinierPreston zones is theoretically analyzed. The analysis was carried out within the framework of the theory of dynamic interaction of defects. An analytical expression for the dependence of the dynamic yield strength on the concentration of impurity atoms has been obtained. The reasons of the different influence of Guinier-Preston zones on inelastic processes at different strain rates are analyzed. It is shown that under high strain rate deformation, nanosized defects affect the nature of the dependence of the dynamic yield stress on the concentration of impurity atoms. This dependence becomes nonmonotonic and has a minimum and a maximum. The maximum corresponds to the transition from the dominant influence of the collective interaction of dislocations on the spectral gap to the dominance of the influence of the collective interaction of impurity atoms. The minimum corresponds to the transition from dominance of dislocation drag by Guinier-Preston zones to dominance of drag by impurity atoms. Numerical estimates of the contribution of the Guinier-Preston zones to the yield strength are made. It is shown that at a high concentration of Guinier-Preston zones, this contribution is very significant. Numerical estimates are made of the concentration of impurity atoms, at which the concentration dependence has a maximum and a minimum.
Keywords: high strain rate deformation, dislocations, Guinier-Preston zones, point defects, nanomaterials.

Maraeva E.V., Permiakov N.V., Moshnikov V.A.
The features of application of eutectic melts based on indium and gallium – page 760
Abstract: In a brief review, the main trends in the use at the present time of eutectic melts based on indium and gallium (EGaIn) are considered. Examples of the use of EGaIn in transistors, capacitors, electrodes, and probe systems (including those in four-probe techniques) are given. The main properties of EGaIn and the spreading of a drop of EGaIn melts are considered, and a detailed scheme of the point-contact four-probe method is given. The main issues discussed in the application of EGaIn in the field of obtaining liquid electrodes, including the formation of gallium oxides, the possibility is revealed of the influence of the spatial environment on the EGaIn droplet and manipulation of microdroplets,. It has been established that among the works of 2022-2023, a large segment is occupied by publications in the field of flexible electronics, intelligent robots, as well as wearable devices (for example, the creation of a metatissue with an antibacterial effect and the ability to be heated with a low energy consumption) and biomedical applications (the development of smart gloves for manipulating gestures, measuring the heart rate of insects).
Keywords: eutectic melts, EGaIn, liquid probes, flexible electronics .

Molchanov S.V., Tretyakov S.A., Ivanov A.M., Kaplunov I.A.
Effect of optical processing on the surface structure of paratellurite single crystals – page 777
Abstract: The effect of optical treatment of the surfaces of a paratellurite single crystal corresponding to the (100), (110), and (001) crystallographic planes was studied. Using a NanoMap WLI1000 optical profilometer, the relief layer of the sample surface (paratellurite single crystal) was controlled. To study the influence of the polishing method, the process was carried out using three techniques – neutral polishing, acid polishing and alkaline polishing. The characteristics of paratellurite surfaces after grinding and polishing are determined. Conclusions are drawn about the predominant use of polishing with chemical reagents. The anisotropy of surfaces differing in crystallographic directions on the speed of grinding and polishing and on the characteristics of the surfaces is shown. Studies of the structure of ground and polished surfaces corresponding to crystallographic planes have shown that the maximum roughness height is observed for the (001) plane. The smoothest surface is achieved for surfaces coinciding with the crystallographic plane (110).
Keywords: paratellurite single crystals, optical surface, grinding, polishing, roughness.

Molchanov S.V., Tretyakov S.A., Kaplunov I.A., Ivanov A.M., Stepanov V.S., Tsvetkov V.P., Tsvetkov I.V., Mikheev S.A.
Micromorphology and fractal parameters of growth surfaces of single crystals of paratellurite – page 787
Abstract: This paper presents studies of the influence of growth conditions of paratellurite single crystals on the side surface of grown boules and the possibility of assessing the quality of crystals based on the values and dynamics of the roughness parameters and fractal parameters of juvenile surfaces. Two single crystals were grown under similar technological conditions and differing from each other in structural quality. Their lateral surfaces were studied using the optical interference profilometer NanoMap 1000WLI employing SPIP and Gwyddion softwares. As a result, roughness parameters of profiles, and fractal parameters of crystal surfaces along the growth direction were obtained,. It was concluded that under conditions corresponding to the formation of stable flows in the melt, the values of the surface roughness over the entire length of the crystal is less than 5 μm, and the fractal energy parameter can be used as a marker of the quality and homogeneity of crystals.
Keywords: paratellurite single crystals, untreated crystal surface, roughness parameters, fractal parameters.

Ostroushko A.A., Vylkov A.I., Zhulanova T.Yu., Russkikh O.V., Tonkushina M.O., Beketov I.V.
Influence of nanoscale additives on the sintering temperature of aluminum oxide – page 799
Abstract: As an initial sample of aluminum oxide, we used material of industrial production for the manufacture of ceramic products. Aluminum oxide powders were prepared as additives introduced into the basic material in an amount of 3% by mass obtained by electric wire explosion as well as in combustion reactions of nitrate-polymer precursor based on polyvinyl alcohol. The obtained additives were characterized in terms of the structure and particle morphology. The samples of the first type included a mixture of different modifications of aluminum oxide, the second type included hydrated aluminum oxide. The first two samples consisted mainly of unaggregated spherical nanoparticles with specific surface area of 20 and 69 m2/g, and the powder obtained in combustion reactions contained flat flake particles, it had a specific surface area of 8 m2/g. The introduction of nano-sized additives led to a shift of the dilatometric sintering curve of compacted samples to lower temperatures, up to 140 degrees maximum. The sample with the largest specific surface was more active in lowering the sintering temperature. The result obtained for the pyrolytically synthesized additive was comparable with the above-mentioned shift in the sintering curve.
Keywords: aluminum oxide, sintering, nanoscale additives, electric wire explosion method, nitratepolymer precursor combustion method.

Pan’kin N.A., Mishkin V.P.
Electronic microscopy of the surface of SCMnCr3 steel after electric spark treatment with a tungsten electrodeanode – page 807
Abstract: The method of scanning electron microscopy was used to study the surface morphology of steel SCMnCr3 after its electrospark treatment with a tungsten (without additives) anode electrode. The following structural elements have been identified: bulges, spherical and disk-shaped inclusions, cracks, pores and particles of irregular shape. Their appearance is due to high temperatures in the interelectrode gap (higher than the corresponding melting temperatures of the main electrode materials) and the non-equilibrium of the processes occurring in it. During the formation of pores, the main mechanism is the release of gases during cooling of the electrode materials in the liquid phase. Macrostresses arising from an electric spark discharge in the surface layers of the electrodes, which exceed the mechanical properties of the electrode materials, lead to the ejection of irregularly shaped solid particles into the interelectrode gap and the appearance of cracks. The appearance of sagging, round/oval inclusions, and spherical particles is associated with the interaction of the liquid phase from the interelectrode gap with the cathode surface.
Keywords: steel, tungsten, electrospark processing, morphology, electron microscopy.

Gafner Yu.Ya., Ryzhkova D.A.
Functioning features of the gas sensor based on SnO2 – page 814
Abstract: Every year modern industry increases the number of technological processes using highrisk chemicals. Therefore, for the uninterrupted work of personnel, it is necessary to minimize the possible consequences of leakage of these substances, but for this, first of all, a clear definition of the maximum permissible concentration of a particular hazardous substance in the air is required. In the last decade, nanomaterials of various types have been used as active elements for gas sensors, and gas sensors based on tin oxide have become the most popular among researchers. In this work, typical reactions of the interaction of the surface of a nanocompacted SnO₂ layer with some detectable gases were studied. It is shown that with an increase in the concentration of the analyzed gas due to its chemical absorption, the electrons previously captured by oxygen are released, which leads to an increase in the number of nanoparticles in the conducting state. This feature makes it possible to use the nanocompacted SnO₂ layer for the determination of nitrogen mono- and nitrogen dioxide in the atmosphere.
Keywords: absorption, semiconductors, nanocompacted material, gas sensors, simulation.

Skachkov V.M.
Properties of diffusion-hardening composite solder modified with vanadium powder – page 823
Abstract: The article considers the effect of vanadium metal powder on the properties of diffusionhardening solder  basedon a low-melting gallium-tin alloy and a solid component consisting of a copper-tin alloy powder. After the introduction of vanadium metal powder in the amount of 5, 10 and 15 wt.%, solder samples were subjected to heat treatment at two different temperatures – 125 and 600°C. The microhardness and thermal stability of composite diffusion-hardening solders are evaluated. It is shown that heat treatment at higher temperatures promotes the transition of solder to an equilibrium state, which leads to an increase in hardness due to the formation and distribution of intermetallic compounds, including nanoscale ones. The phases of vanadium intermetallides formed as a result of interaction with gallium were determined by X-ray phase analysis. Metallic vanadium is wetted by gallium, has limited solubility, and increases solder hardness due to precipitation strengthening.
Keywords: composite diffusion-hardening solders, metal powder, properties, microhardness, differential thermal analysis, vanadium.

Skachkov V.M., Pasechnik L.A., Medyankina I.S., Sabirzyanov N.A.
Changing the properties of diffusion-hardening solders hardened with titanium, zirconium, and hafnium powders – page 831
Abstract: This article presents the results of a study of the properties of three diffusion-hardening solders based on low-melting gallium alloys and copper-tin alloy powder after the introduction of inert metal powders of titanium, zirconium, and hafnium in an amount of 5% each, which is an additive of 15 wt.%. After heat treatment at low temperatures (125°C) in within 24 hours, and after hightemperature treatment (600°C) for 6 hours, the microhardness of the obtained composite diffusionhardening solders was evaluated. Relatively long-term heat treatment at low temperatures does not lead the composition to achieve equilibrium states, possible physico-chemical transformations do not fully occur in them, which shows an increase in the hardness of samples after high-temperature treatment. X-ray phase analysis has determined the phases formed as a result of diffusion hardening, forming micro- and nanoscale intermetallic compounds, and the metal tin released in the form of nanoscale secretions in the intergrain space. Metal filler powders, inert at low temperature to exposure, but well wetted with gallium at high temperatures, interact with it, forming nanoscale intermetallic compounds, additionally strengthening composite solders.
Keywords: composite diffusion-hardening solders, metal powder, titanium, zirconium, hafnium, properties, microhardness, differential thermal analysis.

Stolyarov V.V.
Tribological aspects of nanostructured materials – page 840
Abstract: The article is devoted to the review of structural factors influencing the tribological behavior of nanostructure metals and alloys without lubrication. The scientific significance of this topic is related to the understanding of wear mechanisms and the possibility of its prediction during long-term operation. Particular attention is focused on the effect of the grain size in the range of 0,01-10 µm, as one of the most important structural parameters. Emphasis is placed on materials with ultrafine grains obtained by severe plastic deformation, and nanocrystalline materials obtained by non-deformation methods of sputtering and deposition. It is shown that nanocrystalline films on the contact surface are more preferable for increasing wear resistance, since they are more resistant to structural-phase transformations during friction. Among pure metals, as objects without phase transformations, copper, nickel, aluminum and titanium are considered. As an example of more complex objects, alloys based on titanium (an intermetallic compound with shape memory TiNi and two phases Ti-Al-V alloy) are presented. In addition to the classical scheme of friction during macrodisplacement of the indenter on the contact surface, the fretting friction during microdisplacement is considered.
Keywords: slip, wear, friction coefficient, nanostructure, fretting, roughness.

Suliz K.V., Pervikov A.V.
Structural-phase states of the multicomponent alloy nanoparticles AlCuNiCoCrFe produced by of joint exploding wires – page 851
Abstract: In this work, for the first time, samples of nanoparticles of the multicomponent AlCuNiCoCrFe alloy were obtained by the method of joint electric explosion of wires of Al, Cu, Ni metals and N06003, NiCo29-18 alloys in an argon atmosphere. As the basic mode of wire explosion, a mode close to the matched one was chosen, which made it possible to minimize the influence of the energy of the arc stage of the discharge on the structural-phase state of the forming nanoparticles. It is shown that the obtained samples are represented by spherical particles with sizes ranging from 15 to 500 nm. The number-average size of nanoparticles of the obtained samples varies from 40 to 58 nm. The particle size distribution is described by a normal-logarithmic law, the crystal structure of the particles corresponds to substitutional solid solutions with a bcc and/or fcc lattice. An increase in the Al content in the explosion products leads to an increase in the content of the phase with a bcc lattice in the samples, while an increase in the Cu content leads to an increase in the phase with a fcc lattice. The resulting samples can be used in electrocatalysis.
Keywords: nanoparticles, high-entropy alloys, structural-phase state, electric explosion, current, voltage, powder.

Suliz K.V., Sdobnyakov N.Yu., Pervikov A.V.
Structural-phase states of the multicomponent alloy nanoparticles CoMoFeNiCu produce by of joint exploding wires – page 861
Abstract: Using method of the joint electric explosion of wires of various metals/alloys, for the first time nanoparticles were obtained of a multicomponent alloy with high activity in the ammonia decomposition reaction. It is shown that the obtained samples are represented by spherical particles with an average size of about 40 nm. The crystal structure of nanoparticles contains fcc, bcc phases, as well as a phase corresponding to an intermetallic compound. Energy dispersive analysis data show that in the obtained samples two types of copper segregation in the of particles are observed: enrichment in the central region of the particles and segregation on the surface with formation of a structure characteristic of «Janus» particles. The data obtained indicate the need to involve atomistic modeling methods in the search for optimal quantitative compositions of nanoparticles of multicomponent alloys to provide the necessary desirable structure and functional properties. The prospects for applying atomistic simulation to high-entropy alloys are noted.
Keywords: nanoparticles, high-entropy alloys, exploding wires, catalysis, powder.

Tumarkina D.D., Butkovskii O.Ya., Bolachkov A.V., Burtsev A.A.
Surface topology of mixing entropy after two-pulse laser ablation of stainless steel – page 869
Abstract: The paper presents experiments on crystallization from a melt with an analysis of the morphology of the emerging crystal structures, showing examples of the formation of dendritic crystals. Using energy dispersive X-ray analysis, studies of the microelement analysis of the areas of effect of two pulsed laser beams on the surface of stainless steel have been carried out for irradiation parameters corresponding to the appearance of dendritic structures in the area of effect. It is shown that in the dendritic regions concentrations of all the components of AISI 304 stainless steel are equalized. Estimation of the entropy of mixing from experimental data showed that in the area of surface dendrites or their accumulations, the surface entropy of mixing corresponded to its value for a high-entropy alloy. Based on the maximum entropy production principle, the phase transition temperature was calculated. Although dendritic crystallization should reduce the entropy of the system, experiments show that the entropy of the alloy increases. Preliminarily it can be concluded that this process is associated with a high oxygen content in the region of dendritic crystal formation after laser irradiation. The results presented in this work allow us to conclude that the formation of structures with complex morphology occurs after thermal oxidative ablation.
Keywords: two-pulse laser ablation, dendritic crystals, high-entropy alloys, entropy of mixing, entropy conductivity.

Shomakhov Z.V., Nalimova S.S., Rybina A.A., Buzovkin S.S., Kalazhokov Z.Kh., Moshnikov V.A.
Improving the sensor characteristics of binary and ternary oxide nanosystems – page 879
Abstract: Currently, adsorption gas sensors are of great interest for environmental monitoring. The approaches to improving their properties include synthesis of nanostructured materials of various shapes and modification of the metal oxide chemical composition. The aim of this work is to develop ways to improve the sensor properties of zinc oxide nanowires by changing the surface structure during processing in solutions of tin and iron compounds, as well as adding special precursors during their synthesis. The layers consisting of zinc oxide nanowires were produced by hydrothermal method. Ternary Zn-Sn-O and Zn-Fe-O nanosystems were synthesized as a result of processing of zinc oxide nanowires in solutions containing potassium stannate and iron sulfate, respectively. ZnO nanowires were also synthesized in a solution containing sodium bromide in addition to the general precursors. The surface chemical composition was analyzed using X-ray photoelectron spectroscopy. Sensor properties were investigated by detecting acetone, isopropanol and methanol vapors. It was shown that the sensor response of the produced samples exceeds the response of the initial zinc oxide nanowires. The samples of Zn-Sn-O ternary oxide system have the best response. The improvement of the sensor response may be associated with an increase in the content of adsorbed oxygen ions on the surface of the samples, the presence of metal cations with different properties as well as the formation of heterostructures.
Keywords: gas sensors, metal oxides, nanomaterials, zinc oxide, X-ray photoelectron spectroscopy, adsorption centers.

5. NANOCHEMISTRY – page 888

Belov D.V., Belyaev S.N., Yunin P.A., Nazarov A.A.
Formation of copper clusters in the process of biocorrosion of aluminum alloys by microscopic fungi – page 888
Abstract: In this work, biocorrosion of D16T and AMg6 aluminum alloys under the influence of microscopic fungi was studied. It has been shown that micromycetes produce reactive oxygen species – superoxide anion-radical, hydrogen peroxide, which initiate biocorrosion of metals. The composition products of biocorrosion of D16T and AMg6 after exposure of the alloys on the lawn of a consortium of micromycetes was determined by energy-dispersive X-ray spectroscopy. An X-ray phase study of alloy biocorrosion products was carried out. Scanning electron microscopy and X-ray diffraction analysis show the formation of nanosized and submicron copper clusters. A physicochemical mechanism of biocorrosion of aluminum alloys by microscopic fungi is proposed. An assumption is made about the mechanism of operation of the «zerovalent metal – hydrogen peroxide» systems, which can trigger a cascade of reactions leading to the destructive oxidation of metals. The paper attempts to explain the role of microfungal community biofilms as the main factor in the mycological corrosion of metals.
Keywords: biocorrosion, microbiological corrosion, aluminum alloys D16T, AMg6, zerovalent aluminum, zerovalent copper, microscopic fungi, reactive oxygen species, superoxide anion radical, hydrogen peroxide, copper clusters.

Bibanaeva S.A., Bogdanova E.A., Skachkov V.M.
Synthesis and investigation of functional characteristics of composite materials based on nanoscale hydroxyapatite and synthetic zeolites – page 913
Abstract: The article discusses the possibility of obtaining composite materials based on nanostructured hydroxyapatite synthesized by precipitation from solution and synthetic zeolites by mechanochemical synthesis. The synthesized samples are certified using modern physico-chemical methods of analysis. The influence of the qualitative and quantitative composition of the composite and the temperature treatment modes on the sintering processes and the strength characteristics of the studied samples is showed. It has been experimentally established that the maximum strength characteristics and constant composition are possessed by a sample based on hydroxyapatite, the content of the reinforcing additive in which is 15 wt.%. It was also found that the hydroxyapatitezeolite composite exhibits sorption properties against heavy metal ions and fluorine ions. The studies carried out allow us to recommend the samples obtained for further research in order to introduce it into medical practice, but also as a sorption material for the extraction of ions from aqueous solutions.
Keywords: hydroxyapatite, synthetic zeolites, composite materials, microhardness, sorption.

Bibanaeva S.A., Skachkov V.M.
Sorption of heavy metals from aqueous solutions with synthetic zeolites – page 924
Abstract: The work is devoted to the study of the possibility of using synthetic aluminosilicate zeolites obtained from recycled solutions of alumina production by the hydro-alkaline method as sorbents of heavy metal ions (copper, zinc and iron), as well as fluorine and chlorine ions from slightly acidic aqueous solutions. Natural zeolite and graphite were used as comparison samples under the same conditions. The chemical qualitative and quantitative composition, morphology of the initial reagents and the resulting solutions were studied. It has been established that synthetic zeolite exhibits sorption properties with respect to heavy metal ions that exceed the indicators under the same conditions for comparison objects. Also, positive results were obtained during the sorption of chlorine and fluorine ions. The conducted studies allow us to recommend the obtained samples for further research in order to introduce it not only for the extraction of various ions from aqueous solutions, but also for use in various industries.
Keywords: wastewater treatment, synthetic zeolite, sorption, heavy metals, aluminosilicate.

Blinov A.V., Golik A.B., Gvozdenko A.A., Kastarnova E.S., Orobets V.A., Yakovenko A.A., Bakholdina T.N.
Development of a biologically active nanosystem based on riboflavin, a microelement of copper and L-lysine amino acid – page 930
Abstract: А biologically active nanosystem based on riboflavin, copper microelement and the amino acid lysine copper lysinatoriboflavinate has been developed. The obtained sample of the biologically active additive was studied by a complex of modern methods of analysis, namely: spectrophotometry, scanning electron microscopy, spectrophotoluminescence spectroscopy. In addition, computer quantum chemical modeling was carried out. It has been established that the most energetically favorable model of a biologically active nanosystem based on riboflavin, a trace element of copper and lysine is a model in which riboflavin is bound to the copper ion through the enol oxygen at C₂ and the neighboring nitrogen heteroatom N₃, and lysine is bound to the copper ion through the carboxyl and amino groups in α position. As a result of the analysis of micrographs of a biologically active nanosystem based on riboflavin, copper microelement and lysine amino acid, it was found that the particles have an acicular structure, the width of individual crystals is from 100 to 300 nm, and the length reaches several microns. The energy-dispersive X-ray spectra of a biologically active nanosystem based on riboflavin, the microelement copper, and the amino acid lysine coincide with the theoretical concepts of the structure of the elements under consideration. The analysis did not show the presence of impurity compounds, which may allow us to judge the high purity of the developed compound.
Keywords: trace element copper, essential amino acids, quantum chemical modeling, vitamin B2.

Blinova A.A., Kastarnova E.S., Pirogov M.A., Kuznetsov Ye.S., Leontiev P.S., Filippov D.D.
Determination of the optimal configuration of the molecular system «manganese silicate nanoparticles-an essential amino acid» – page 940
Abstract: In this study, the optimal configuration of the molecular system «manganese silicate nanoparticles – essential amino acid» was determined using quantum chemical simulation. To begin with, quantum chemical simulation of individual molecules of manganese silicate and essential amino acids was carried out, after which molecular systems «manganese silicate nanoparticles – essential amino acids» were modeled, in which an oxygen atom attached to silicon atom in manganese silicate was combined with an ionized amino group of amino acids. As a result, it was found that the molecular systems «manganese silicate nanoparticles – essential amino acids» are energetically advantageous and chemically stable. Based on the data obtained, it can be concluded that the optimal configuration of these molecular systems is the interaction of manganese silicate with lysine through the ionized α-amino group of lysine. This molecular system has the highest values of the difference in total energy (ΔE = 73.268 kcal/mol) and chemical hardness (η = 0.144 eV), which are indicators of energy benefits and chemical stability of molecular system. After mixing manganese acetate, L-lysine and sodium silicate, manganese silicate nanoparticles stabilized with L-lysine were obtained.
Keywords: manganese silicate nanoparticles, essential amino acids, quantum chemical modeling, lysine, IR spectroscopy.

Golovanova O.A., Kiselev V.M.
Mathematical modeling of formation of nanocrystalline calcium oxalate under physiological conditions – page 950
Abstract: For the first time, a physicochemical model of the formation of poorly soluble compounds in the kidney nephron was developed on the basis of a mathematical description of the ideal displacement reactor. As a result of mathematical modeling, it was found that under normal physiological conditions, the formation of a solid phase is not the dominant process, which explains the absence of crystalline formations in the kidneys in healthy people. An increase in the concentration of precipitate-forming ions, corresponding to certain conditions of the human body, leads to the occurrence of local high supersaturations in certain areas of the nephron, which can lead to the formation of solid phase nuclei, their fixation and further growth. It is shown that the calculations of material balances, flow movements, as well as the concentration profiles of components in the nephron determine the possibility of predicting the behavior of the model system with variations in the parameters and conditions that affect the course of the crystallization process (concentration, fluid flow, hydrodynamic regime, etc.), which will allow developing effective methods for the prevention and treatment of urolithiasis, including the dissolution of already formed aggregates.
Keywords: crystallization, calcium oxalates, saline, model, plug flow reactor, nephron, material graph.

Golovanova O.A., Tomashevsky I.A.
Synthesis of nanocrystal calcium carbonate from bile in the presence of amino acids – page 962
Abstract: In this paper, we studied the effect of amino acids in the composition of bile, the formation of various modifications of calcium carbonate (aragonite, vaterite, calcite). In this work, 22 samples of calcium carbonate in bile were synthesized by varying the concentrations of amino acids (histidine, methionine, arginine and tryptophan). For the amino acids methionine and arginine, their stabilizing effect with respect to metastable aragonite has been proven: with an increase in their concentration in bile, an increase in the mass fraction of aragonite in the composition of the solid phase occurs. Optical microscopy showed the presence of vaterite spherulites in all obtained powders. The results of photon correlation spectroscopy correlate with the data of X-ray phase analysis. It is shown that calcium carbonate microparticles with a radius of less than 10 µm are represented by three fractions. It has been shown that syntheses involving histidine and tryptophan, in which, with increasing amino acid concentrations, an increase in the proportion of the small-sized fraction and a decrease in the proportion of the large-sized ones are observed. Thus, all studied amino acids have the potential to be used as medicines for the treatment and prevention of nanocholelithiasis.
Keywords: gallstones, crystallization, calcium carbonates, amino acids, additives, vaterite, radius, morphology.

Zaritovskii A.N., Kotenko E.N., Grishchuk S.V., Glazunova V.A., Volkova G.K.
Synthesis of carbon nanomaterials by means of microwave-assisted catalytic pyrolysis of cellulose – page 973
Abstract: The growing demand for carbon nanotubes, which are typical representatives of the class of carbon nanomaterials and have unique physical and chemical properties, necessitates the search for available and renewable hydrocarbon resources for their production and development of an energyefficient and a highly productive synthesis method. The prospects of using lignocellulosic biomass and its wastes as a carbon source for the synthesis of carbon nanotubes by means of microwave catalytic pyrolysis are considered. The expediency of research in this direction is emphasized. It is noted that one of the parameters responsible for the process of pyrolytic synthesis of carbon nanotubes is the concentration of microwave radiation absorber, which determines pyrolysis temperature. The effect of changing the concentration of microwave absorber in reaction mixture on the catalytic synthesis of multi-walled carbon nanotubes during microwave pyrolysis of cellulose has been studied. It is shown that a change in the microwave acceptor content from 10 to 30% is accompanied by an increase in the concentration of multi-walled carbon nanotubes of disordered morphology in reaction mixture. A twostage pyrolysis-synthesis process is suggested. The results of transmission electron microscopy and Xray phase analysis of the obtained products are considered.
Keywords: plant raw materials, carbon nanotubes, cellulose, microwave absorbers, concentration, microwave processing, pyrolysis.

Krut’ko V.K., Maslova L.Yu., Musskaya O.N., Kulak A.I.
Formation of biomimetic apatite on calcium phosphate foam ceramics in standard and carbonate-free model solutions – page 982
Abstract: The biomimetic apatite was formed in the carbonate-free Simulated Body Fluid model solutions of standard composition on calcium phosphate foam ceramics, consisting of α/β-tricalcium phosphate and β-calcium pyrophosphate. The apatite phase composition was determined by the composition of Simulated Body Fluid solution used during soaking. The equilibrium shift in the model solution during the interaction of calcium phosphate foam ceramics with ions of the solution leads to the apatite precipitation in the aggregated particles form. The excess content of H⁺ ions in carbonatefree Simulated Body Fluid leads to pH sharp fluctuations and the inclusion of hydrated СaClH₂PO₄ impurity into apatite spherulites. An increase in the soaking time in Simulated Body Fluid model solutions to 21-28 days leads to coarsening of apatite spherulites to 5-6 µm. The foam ceramics surface morphology after soaking changes insignificantly with a slight decrease in the through porosity by 1-3% and two times increase in static strength due to the healing of microdefects in the foam ceramics structure.
Keywords: calcium phosphate foam ceramics, tricalcium phosphate, SBF (Simulated Body Fluid), biomimetic apatite, spherulites.

Menshikov S.Yu., Malyshev A.N., Kurmacheva V.S., Tonkushina M.O., Ostroushko A.A.
The effect of FeSO4 and nanocluster polyoxometalates on the oxidation of phenol persulfate in an alcohol medium – page 992
Abstract: The catalytic properties of FeSO₄, nanocluster ferro-molybdenum polyoxometalate {Mo₇₂Fe₃₀} and nanocluster molybdenum polyoxometalate {Mo₁₃₂} have been studied during the oxidation of phenol in ethanolisobutanol solution with persulfate. To determine the oxidation products, phenol, ethanol and isobutanol of an acidic nature, sulfonic cation exchanger KU-2 (the grade of ion exchange resin established by the state standard of the Russian Federation GOST 20298-74) was added to the reaction mixture in each experiment to catalyze the esterification reaction of acid oxidation products with the initial alcohols. Acid esterification products were identified by the vapor-phase chromatography method with a mass spectroscopic detector. According to the conversion of phenol, ethanol and isobutanol, the catalytic properties of a homogeneous FeSO₄ catalyst (similar to Fenton’s reagent) with heterogeneous catalysts (polyoxometalates) were compared. These data suggest the possibility of further searching for heterogeneous catalysts containing Fe and Mo in their composition during the destruction of phenol by peroxide compounds.
Keywords: polyoxometalate, Keplerate, FeSO4, catalytic properties, phenol oxidation in ethanol-isobutanol medium, potassium persulfate, gas chromatography mass spectrometry.

Musskaya O.N., Krut’ko V.K., Glazov I.E., Kulak A.I.
Liquid-phase synthesis of calcium phosphates in the presence of gallic acid – page 1000
Abstract: Acid, medium, and basic calcium phosphates were obtained by liquid-phase synthesis from aqueous solutions of calcium chloride and ammonium hydrogen phosphate at Ca/P molar ratios of 1,0-1,67 and pH 5-11 in the presence of a polyphenol compound (gallic acid). Using X-ray phase analysis and IR spectroscopy, it has been shown that brushite is formed in a slightly acidic medium (pH 5-6) at a Ca/P molar ratio of 1,0, the unit cell size of which can decrease in the presence of gallic acid. In an alkaline environment (pH 8-11), the polyphenolic compound chelates calcium ions, which leads to the formation of amorphized calcium phosphate, which after heating at 800°C turns into β-tricalcium phosphate and hydroxyapatite. It was found that the presence of gallic acid promotes the formation of basic calcium phosphate at a lower molar ratio (Ca/P 1,5) than for stoichiometric hydroxyapatite (Ca/P 1,67). It has been shown by thermal analysis that the liquid-phase synthesis of calcium phosphates in the presence of gallic acid promotes the transformation of brushite into calcium pyrophosphate, and amorphized calcium phosphates into tricalcium phosphate and hydroxyapatite, upon high-temperature treatment.
Keywords: gallic acid, liquid-phase synthesis, brushite, amorphized calcium phosphates, hydroxyapatite, tricalcium phosphate, calcium pyrophosphate.

Nalimova S.S., Shomakhov Z.V., Chuprova A.D., Guketlov A.M.
Synthesis and diagnostics of gas-sensitive nanostructures based on molybdenum compounds – page 1009
Abstract: In recent years, various transition metal dichalcogenides have been widely investigated, which are of interest for many applications, including gas sensors. In this work, some gas-sensitive nanostructures based on molybdenum disulfide and molybdenum oxide were synthesized by hydrothermal method. The surface chemical composition of the samples was studied by X-ray photoelectron spectroscopy. The gas-sensitive properties of the synthesized structures to isopropyl alcohol and acetone vapors at different working temperatures were analyzed. It was shown that as a result of heat treatment at 150°C, partial oxidation of molybdenum disulfide occured. Annealing of MoS₂ samples at 400°C led to complete oxidation to MoO₃. Analysis of the gas-sensitive properties of the structures showed that molybdenum oxide has the maximum response to isopropyl alcohol and acetone vapors in the entire temperature range under study. Both molybdenum disulfide and molybdenum oxide show a better response to isopropyl alcohol vapors compared to acetone vapors.
Keywords: chemisorption gas sensors, molybdenum disulfide, molybdenum oxide, X-ray photoelectron spectroscopy.

Ostroushko A.A., Tonkushina M.O., Zhulanova T.Yu., Kudyukov E.V., Golub A.Ya., Russkikh O.V.
Peculiarities of texture formation in strontium hexaferrite-based materials when produced from organic nitrate precursors – page 1017
Abstract: The processes of strontium hexaferrite (permanent magnet material) fabrication in combustion reactions followed by heat treatment of organic nitrate precursors containing glycine or polyvinyl alcohol have been studied. The formation of iron-glycine complexes of organic precursor components affects the formation of the morphology of the obtained samples. When using glycinecontaining systems during combustion, a branched fibrous texture of the material with extended internal cavities with elongated oxide particles emerges. Such samples have a higher coercivity; the external magnetic field has no significant influence on the texture formation during combustion. It was established that charges are generated in precursors during their combustion, which manifests itself in the appearance of a potential difference between the ground and the precursor. In this case, the appearance of lower intensity charges allows us to obtain samples with higher magnetization, as well as with a greater ability to increase the magnetic characteristics during further thermomagnetic processing.
Keywords: strontium hexaferrite, synthesis, organic nitrate precursors, magnetic properties, texturing.

Sviridova T.V., Yakubovskaya Z.A., Odzhaev V.B., Sviridov D.V.
Mechanism behind structural changes accompaning the solid-state polymerization in the molybdenumvanadium mixed oxide films – page 1029
Abstract: In this paper we investigate the changes in the surface topology of inorganic polymerderived films resulted from photostimulated polymerization. With the use of the atomic-force microscopy, the surface structure changes of mixed molybdenum-vanadium oxide thin films (V₂O₅:MoO₃ = 3:2) resulted from the UV light-induced polymerization was investigated. The analysis of atomic-force images evidenced that the solid-state polymerization in the mixed oxide films obtained by condensation of corresponding oxoacids occurs through 3D mechanism. As the result of exposure, MoO₃/V₂O₅ films lose the intrinsic anisotropy which is due to the directional agglomeration of belt-like mixed oxide oligomers. The photopolymerization processes in the mixed oxide film yield agglomerates of nuclei built from the faceted nanometer-sized pseudocrystallites. The exposure is also accompanied with solid-state recrystallization of initially amorphous oxide resulting in the rougher relief of the exposed film. The selective acidic etching uncovers the latent structure of the film, this etching being accompanied with pseudocrystallite dispergation that results in the smoothing of the microrelief of the oxide film surface. These structural features of photosensitive mixed oxide MoO3/V2O5 films facilitate their application as the inorganic photoresists.
Keywords: photopolymerization, molybdenum-vanadium mixed oxides, thin films, nanostructure, inorganic photoresists, atomic force microscopy.

Suprunchuk V.E.
Evaluation of the properties of the fucoidan/Fe3O4 nanocomposite as a transport agent of covalently bound molecular cargo – page 1039
Abstract: Magnetically controlled transport of drugs with targeted release of molecular cargo expands the possibilities of clinical therapy. This article explores the possibility of creating nanoparticles based on fucoidan modified with magnetite for biomedical purposes. The possibility of immobilizing a modelling fibrinolytic enzyme with a cross-linking agent was studied. The maximum loading of the enzyme is 2.06±0.09% of the mass. The particle size with immobilized alteplase according to scanningelectron microscopy was 94.4±24.3 nm, hydrodynamic diameter – 370 nm, zeta potential – -1.66±0.06 mV. The saturation magnetization of the sample is 6 emu/g. To understand the mechanisms of molecular load release, five kinetic models were applied to the results obtained: zero order, Weibull, Hill equation, Higuchi, Korsmeyer-Peppas. The use of mathematical modeling showed that the best model for describing this process is the Korsmeyer-Peppas kinetic equation (r² = 0.97), and the release process is controlled by the Fick diffusion. The resulting biocomposite material is a promising candidate as a nanocarrier for an enzymatic agent.
Keywords: fucoidan, magnetite, magnetic nanoparticles, targeting, targeted delivery, alteplase, release kinetics, variable magnetic field.

Turovtsev V.V., Chernova E.M., Miroshnichenko E.A., Orlov Yu.D.
Effect of free valence on the electronic structure of n-alcohol radicals – page 1049
Abstract: The paper presents the results of a study of the effect of free valence (when a hydrogen atom is separated) on the electronic structure of n-alcohol radicals by the example of radicals of nheptanol derivatives (C●H_2–(CH₂)₆OH, CH_3–C●H-(CH₂)₅OH, C₂H_5–C●H-(CH₂)₄OH, C₃H_7–C●H-(CH₂)₃OH, C₄H_9–C●H-(CH₂)₂OH, C₅H1_1–C●H-CH₂OH, C6H_13–C●H-OH, C7H_15-O●). Geometry optimization and the electron density distribution in these compounds was obtained by the density functional method B3LYP/6-311++G(3df,3pd) 6d 10f. The electronic structure of the selected molecules and radicals was investigated within the framework of the «quantum theory of atoms in a molecule» (QTAIM): the electronic parameters of atoms and atomic groups were calculated, the spin density distribution was studied, the concepts of «radical center» and «free valence» were quantitatively characterized. The inductive effect and the tolerability of atomic groups are considered, and a qualitative scale of group electronegatives is compiled. The disturbing effect of various atomic groups, including those containing free valence, on the hydrocarbon chain is compared by comparing the integral parameters of the groups included in the compounds under study with the parameters of the «standard» groups.
Keywords: quantum theory of atoms in molecules, electron density, electronegativity, inductive effect, free valence, radical center.

Khizhnyak S.D., Ivanova A.I., Volkova V.M., Barabanova E.V., Pakhomov P.M.
Green synthesis of silver nanoparticles. Complementary techniques for characterization – page 1059
Abstract: The work presents the results of green synthesis (biosynthesis) of silver nanoparticles using aqueous extracts of maple and oak leaves. The efficiency of the synthesis, size and shape of the formed nanoparticles were studied using UV-visible spectroscopy, dynamic light scattering, atomic force microscopy and scanning electron microscopy techniques. It was found that the formation of silver nanoparticles is accompanied by the appearance of a plasmon resonance band in the electronic spectra of aqueous extracts, the maximum of which depends on the concentration of silver nitrate and is in the range of ~420-429 nm in the spectra of maple leaves, and in the spectra of oak extracts there is a shift towards longer wavelengths ~425-435 nm, which correspond to the formation of nanoparticles of larger size. According to the dynamic light scattering data, the size of nanoparticles in the maple extracts is of about 60-68 nm and in the oak samples of ~107 nm. The differences in the size and shape of nanoparticles obtained in the maple and oak phytoextracts detected by atomic force microscopy and scanning electron microscopy are explained by the different composition of bioactive substances in the plants involved in the reduction of silver ions and stabilization or modification of the surface of silver nanoparticles.
Keywords: green synthesis, silver nanoparticles, surface plasmon resonance, scanning electron microscopy.

Cherkesova N.V., Mustafaev G.A., Mustafaev A.G.
Gate dielectric nitrization and effect on changes in the density of interlayer states of MOS structures – page 1070
Abstract: The processes occurring in the silicon-oxygen-nitrogen system are of great practical importance, since dielectric layers made from materials of this system are widely used as barriers to the penetration of impurities, elements of storage capacitors, field insulating layers, etc. Interest in the creation of such dielectrics has increased in connection with the use of the rapid thermal annealing stage in technological processes, which are accompanied by the appearance of fast surface states and mechanical stresses on the interface. As a result of the study, it was determined that the change in the threshold voltage in MDS structures is associated with the capture of electrons by the traps formed in the bulk of the semiconductor. MDS structures with nitrided oxide have better stability than conventional oxide. Studies have shown that the suppression of the formation of states at the interface depends on the degree of nitriding. The characteristics of MDS structures under the influence of irradiation substantially depend on the temperature and duration of fast thermal nitrization.
Keywords: metal–dielectric–semiconductor, silicon oxynitride, nitrization, gate dielectric, silicon dioxide, heat treatment.

Shkrumeliak V.A., Golovanova O.A.
Synthesis and study of the structure of lanthanum (III) compounds and cerium (III) with aspartic acid – page 1080
Abstract: A significant part of modern research is devoted to synthesis and study of the structure of compounds of rare earth elements with bioligands – these are those ligands that participate in biochemical processes. Compounds of rare earth elements with amino acids are of particular interest to study, since they are the most important bioligands, natural nanoscale molecules. In the course of the work, compounds of lanthanum (III) and cerium (III) with aspartic acid were synthesized. White crystalline precipitates were obtained for the «La-Asp» (1:2) and «Ce-Asp» (1:3) systems. With the help of optical microscopy, the fundamental difference between the crystals of synthesized compounds (in shape and size) from the crystals of the starting substances used for synthesis is proved. The results of IR-Fourier spectroscopy showed that metal ions interact with the carboxyl group of aspartic acid. The results obtained during the spectrophotometric analysis of the filler fluid for the «La-Asp» system (1:2) made it possible to simulate the spatial structure of this compound taking into account the amount of aspartic acid bound to lanthanum (III) ions. The synthesized compounds are promising for their further use in medicine.
Keywords: rare earth elements, complex compounds of lanthanum (III) and cerium (III), amino acids, aspartic acid, ligands.