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Silicon and silicon-based nanoparticles (SiNP) attract scientific attention due to the biocompatibility and assimilation of silicon by body tissues. Iron-doped SiNP (SiFeNP) allow the use of ferromagnetic properties of iron for NP detection and the possibility of therapeutic application of SiFeNP. The purpose of this work was to analyze the interaction of SiFeNP with epithelial cells (EC) COLO357 and SW620 and human peripheral blood lymphocytes (PBL). SiFeNP were obtained by laser ablation and divided into the NP1 and NP2 fractions of 100 and 150 nm size, respectively. Cytotoxicity, apoptosis induction, reactive oxygen species (ROS) production, and lysosome metabolism were analyzed using in vitro methods. EC were found to efficiently incytosed both types of NPs, which resulted in the increase in the granularity of cells. NP did not cause apoptosis or EC necrosis, but accumulated in lysosomes, which led to a decrease in the membrane potential of lysosomes. In turn, a decrease in the level of EC metabolism led to a gradual (24 h) increase in ROS production by 10–15%. NP1 caused more ROS than NP2, and accumulated more in the EC, which may be the result of a difference in the particle size. SiFeNP did not interact with PBL. Thus, the total cytotoxicity of SiFeNP did not exceed 20%, which is associated with a decrease in lysosome metabolism and insignificant ROS production.

An alloy based on the Heusler phase Fe2TiAl is obtained for the first time by self-propagating high-temperature synthesis (SHS). Experiments have shown that the alloy is synthesized in the thermal explosion mode. Features of the structure- and phase formation during combustion in the 2Fe–Ti–Al system are studied and their mechanisms are proposed. The electrophysical properties of the combustion product are studied.

—The influence of various schemes of thermomechanical treatment (TMT) on the structure and properties of two sintered nickel-rich binary TiNi powder alloys is shown. TMT is found to decrease the average grain size and to increase the strength characteristics, the alloy density, and the plasticity relative to the initial sintered state. The influence of TMT on the phase composition of the alloy is detected by X-ray diffraction. TMT is shown to promote the formation of the triclinic R-martensite or strain aging with the precipitation of the Ti2Ni3 phase.

The aggregation of a series of mono- and dilithionaphthalenes in THF solutions in the presence of tetramethylethylenediamine (TMEDA) and pentamethyldiethylenetriamine (PMDTA) was studied by NMR spe...

NiO nanopowder is produced through plasma-chemical synthesis in a low-pressure arc reactor in an atmosphere of 80% Ar + 20% O 2 at a pressure of 40 (sample 1) and 180 Pa (sample 2). The crystalline, morphological, and impedance properties are studied by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and impedance spectroscopy. It is shown that an increase in pressure leads to the synthesis of nanomaterials with fundamentally different crystalline and electrical properties. Sample 1 shows a non-stoichiometric composition (Ni 42 O 58 ), a face-centered cubic lattice, and a size of coherent scattering regions (CSR) of 16 nm. The impedance studies shows that the frequency dependences are well described by the Debye relaxation model, at low frequencies the real part of the dielectric constant is equal to 35, and thermal studies show a negative temperature coefficient of resistance (NTCR). Sample 2 has an amorphous structure, almost stoichiometric composition (Ni 48 O 52 ). At low frequencies, the real and imaginary parts of the dielectric constant reaches 105. The anomaly is explained by the formation of a double electric layer near the electrodes due to proton-ion conductivity.

The kinetics of the reaction between fluorine and benzene is studied experimentally at T = 293 K. Competitive reactions are used to find a reaction rate constant. The interaction is studied in a low-pressure flow reactor, and mass spectrometry is used to control the concentration of reagents and products. The reaction between fluorine atoms and methane is used as a competitive one. The ratio of rate constants of the studied reaction (k1) and a competitive one (k2) is found for the first time: k1/k2 = 4.4 ± 0.3. A rate constant is calculated for the reaction of fluorine atoms with benzene using literature data: k1 (293 K) = (2.7 ± 0.5) × 10‒10 cm3 molecule−1 s−1.

Kinetics of urethane formation from isophorone diisocyanate and polycaprolactone diol and poly(butylene adipate) in acetone was studied by IR spectroscopy. It was found that poly(butylene adipate) is the most reactive oligoesterdiol, with the reaction being both non-catalyzed and catalyzed by dibutyltin dilaurate. It was shown that the cycloaliphatic group of isophorone diisocyanate is an order of magnitude more active than the aliphatic one in catalytic reactions of isophorone diisocyanate with investigated oligoesterdiols. Furthermore, waterborne polyurethanes based on the studied oligoesterdiols were synthesized and characterized by DLS, DSC, and TGA methods.

Vertical turbulent dust aerosol fluxes are determined on the basis of measurements of fluctuations of the content of aerosol particles and the vertical component of the wind velocity for a desertified territory of Astrakhan oblast. The normalized flux or the uplift velocity of the dust aerosol reached 5 cm/s. It is found that the vertical turbulent aerosol flux is significantly affected by convective-related variations in the horizontal and vertical components of the wind velocity. It is shown that the daily variability of the uplift velocity of the aerosol agrees with that of the turbulent heat flux and that the mass dust aerosol flux is correlated with a maximum particle size of ~1.5 µm.

The article describes the experience of using allografts in surgery of the main arteries of the lower limbs. The urgency of using bioprostheses is briefly shown. The management of patients with infectious complications remains an unsolved problem in vascular surgery. Reconstructive vascular surgery is often repeated. Operations are often performed in the presence of extensive necrosis and trophic ulcers. The autovein is not always available for reconstruction of the main artery , which is why the issue of choosing a material for repeated reconstruction remains relevant. The medical literature has shown the tendency of xenoprostheses to aneurysmal transformation in the postoperative period. There is not a lot of information in the world and domestic sources on the use of arterial allografts. The lack of clear indications and contraindications for use, optimal preservation periods, the choice of the necessary preservatives and a suitable medium do not allow the widespread use of allografts in practical surgery if there is access to the technology of vascular collection, conservation and transplantation. The problem of using allografts requires further study. In this regard, the experience of using allografts in two non­standard clinical situations is presented. It was concluded that it is possible to effectively use freshly prepared arterial allografts from a postmortem donor during reconstruction in patients with critical ischemia of the lower extremities in the absence of a suitable autovein and the impossibility of using a synthetic prosthesis.

The financial situation and incomes of Simbirsk residents of the second half of the 19th — early 20th centuries are considered. The relevance of the study is due to the fact that understanding urban everyday life is impossible without an idea of the income that the citizens had. It is noted that in the period under review, class division is gradually turn to the division of society in the capitalist way, differentiation by income is confirmed, which is reflected in the mentality and administrative management. The difference between the population of Simbirsk and other Volga cities is shown: the share of the nobility among the urban population was twice as high as in neighboring cities, and the share of the peasantry was half that in Samara and four times less than in Saratov. A review of statistical information on the income of various classes and categories of employment is carried out. Particular attention is paid to the development of entrepreneurship and merchants and income in this area. It is noted that in Simbirsk, the development of entrepreneurship was slower than the average Russian values. The results of a comparative analysis of the standard of living and material situation of citizens living in Simbirsk with the indicators of other cities are presented. It is stated that for the sustainable development of capitalist relations, the introduction of financial organizations and entrepreneurship from the outside was necessary in Simbirsk.

The effect of consolidation and thermal treatment on the structure, local chemical composition, and martensite transformation temperatures of the Ti28Ni50Hf22 powder alloy is studied. It is shown that, in the powder state, the alloy is characterized by an inhomogeneous distribution of Ti and Hf in the matrix, whose concentration spread may reach 27 at %. Vacuum sintering and homogenizing annealing lead to equalization of the chemical composition. During powder sintering, the spread of Ti and Hf concentrations reduces from 27 to 2 at %. Subsequent vacuum annealing at a temperature of 1000°C for 4 h for a sintered sample additionally reduces the spread of concentrations from 4 to 2 at %, while the increase in the annealing duration from 4 to 16 h does not affect the uniformity of the element distribution. It is established that, at a large inhomogeneity of the chemical composition, the differential scanning calorimetry (DSC) methods fail to record the occurrence of martensitic transformation in the melt. However, homogenization of the alloy leads to the appearance of endothermic peaks on the DSC curve upon heating, as well as to narrowing of the interval of reverse martensitic transformation.

The structure of hydrated ions of dichloroacetic acid (DCA) is established by electrospraying aqueous solutions of DCA into the vacuum chamber of a mass spectrograph. At an acid concentration of 0.01 mol/L, the number of hydrated ions decreases monotonically with an increase in the degree of their hydration. The resulting mass spectrum provides information on the distribution of hydrated ions in solution, which makes the mass spectrographic method of spraying electrolytes in a vacuum applicable for determining the composition of electrolyte solutions in environmental studies.

This article investigates the microstructural features, phase composition, and electrophysical properties of Co2TiAl intermetallic alloy produced by self-propagating high-temperature synthesis (SHS) in combination with pressing. For the first time, a practically single-phase alloy based on the Co2TiAl Heusler compound with the weight content of at least 82% was produced using SHS; the synthesis products also contain TiCox intermetallic compounds of variable composition. The unit cell parameter of Co2TiAl was a = 5.8433 ± 0.0002 A. Metallographic analysis of the microstructure after SHS pressing demonstrated structure densification and decrease in porosity in comparison with samples produced by regular SHS without application of load to the combusted sample. The average microhardness of the synthesized alloy was Hμ = 5650 MPa, and the electrical resistance of the synthesized material at ambient temperature was 1.35 μΩ m. Variations of specific electrical resistance were studied in vacuum of 1.33 × 10–3 Pa in the temperature range of 77–1300 K. At temperatures above 600 K, the electrical resistance as a function of temperature ρ(T) in Co2TiAl alloy exhibits a decrease in slope; that is, for the given alloy, there exists the so-called effect of resistance saturation. The Curie point corresponding to transition from the magnetic to paramagnetic state was 133 K.

Since 1964, the Kaliningrad branch of Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences (IZMIRAN) has been conducting regular observations of the parameters of the lower atmosphere, ionosphere, and variations in the Earth’s magnetic field. The base of the measuring equipment, located in Ulyanovka village, Kaliningrad region (54° N, 20° E) consists of ionosonde for the vertical sounding of the ionosphere; two-frequency GPS/GLONASS receivers, which are used to determine the total electron content in the ionosphere; magnetic variation stations for the continuous recording of variations of the three components of the Earth’s magnetic field vector and calculating the local K-index; and a weather station. The simultaneous observations of variations in the magnetic field, as well as the ionospheric and meteorological parameters in the same observatory, offer a wide range of opportunities to study the atmospheric-ionospheric relations. This article provides a brief description of all the tools, provides a method for transmitting and storing the time series of measured parameters, and also presents examples of using these data for various geophysical studies.

Ionospheric disturbances during meteorological storms in the Kaliningrad region with a wind amplification of 8 points or higher on the Beaufort scale for the period 2010–2018 are analyzed. Ionospheric observations made under conditions of low geomagnetic activity are considered. Analysis shows that all of the selected events were accompanied by disturbances of the total electron content (TEC) and/or the electron concentration at the maximum of the F2 layer ionosphere (foF2) a few hours after reaching the maximum in the surface wind speed. Moreover, in four of six cases, the disturbances exceed the standard deviation of the values from the average median values by two times. Negative disturbances of TEC and foF2 (decrease in values) were observed in four cases, and positive disturbances (an increase in TEC and foF2) were observed in two cases. Disturbances were observed for at least 3 h, mainly in the daytime. The relative disturbances of the TEC due to meteorological storms exceed the corresponding foF2 disturbances.

The article is devoted to the theoretical foundations and analysis of the experience of subjects of the Russian Federation in the field of regional development risk management. The article examines the concept of risk, its difference and relationship with the concepts of uncertainty, threat, danger, security and others. It is determined that dangers are constantly present in the regional economy. And risk, as a measurable uncertainty with multiple outcomes, for which the probability of occurrence of a risk event is calculated, is manifested as a result of the occurrence of a hazard. When comparing the concepts of risk and security, this means that the security of the regional economy is manifested in the ability to resist threats and manage risks, and not in the complete absence of dangers. It is revealed that ISO standards distinguish between the concepts of risk management and risk management. For further discussion, risk management is understood as a systematic approach to using the full range of mechanisms available to public authorities to reduce emerging risks and threats to the socio-economic development of the region. Further, the analysis of risk management in the practice of regional management on the example of the Omsk, Novosibirsk and Tyumen regions is carried out. The relevant tools in the activities of government bodies, such as territorial development strategies, state programs and projects, were identified, which allowed us to introduce a classification of risks with the allocation of strategic, tactical risks of territorial development and project management risks, among which there is a strategic level. The analysis of the implemented tools for compliance with the mandatory stages of risk management showed mainly the absence of risk identification, unified requirements for risk accounting and systematic risk management of regional development. Among the assessed regions, the Tyumen region has the best practices in terms of risk management. For a more detailed analysis authors highlighted the key institutional and instrumental elements of risk management such as risk committee, strategic risk map, risk register, action plan for risk management, and defined logical relationships between them.

–A material based on the V2AlC MAX phase has been obtained for the first time by the method of self-propagating high-temperature synthesis (SHS) using a reaction mixture of vanadium oxide(V) and (IV) powders with aluminum and carbon (graphite). The obtained material was characterized by X-ray diffraction and energy-dispersive X-ray spectroscopy. The Rietveld method was used to perform quantitative analysis. The synthesized material based on the V2AlC MAX phase is an electrical conductor that demonstrates the metallic behavior of conductivity in the entire measured temperature range of 300–1300 K in the vacuum of 2 × 10–3 Pa. It has been suggested that the V2AlC phase makes a decisive contribution to the electrical resistance of the synthesized material that may be caused by the formation of V2AlC nanolaminate grains contacting with each other in the bulk of the material.

The mass-energy distributions of fragments formed in reactions 16,18O + 232Th, 238U, and 22Ne + 232Th, 238U at energies near the Coulomb barrier are measured to study the role of multimodal fission in the reactions of light ions with strongly deformed actinide nuclei. It is found that at these energies, multimodal fission affects significantly the mass–energy and angular distributions of fragments that results in an increase of the width of mass distributions and large angular anisotropy as in the case of quasifission.

Introduction. Pharmaceutical dosage forms with diosmin are allowed for medical use in Russian Federation. Simple and informative methods of diosmin quantitation for drug quality control are needed. Aim: determination of metrological parameters of diosmin quantitation in pharmaceutical dosage forms by UV-spectrophotometry. Matherials and methods. The study subjects Venarus, Detralex (tablets, suspension), Phlebopha. Diosmin were quantified by UV-spectrophotometry. The reference-specific absorbance values of diosmin at wavelengths of 268 and 370 nm by the parameters of calibration were determined. Statistical data processing was carried out by the methods of variation statistics, correlation, one-way analysis of variance using computer programs ChemMetr 1.0, ChemMetr Evaluation 1.0, Statistica 6.0 (Statsoft Inc., USA). Results. The range of diosmin quantitation by UV-spectrophotometry was revealed for the wavelength of 268 nm 0,0001-0,001%, 370 nm 0,0002-0,002%. The reference-specific absorbance values for diosmin at the wavelength of 268 and 370 nm in a sodium hydroxide solution 0,02M were 463,0 24,6 and 259,0 9,9 respectively. The mean errors of diosmin concentrations in pharmaceutical dosage forms were revealed for the wavelength of 268 nm 8-12% and for 370 nm 6-8%. Prognostic calculation of the sample preparation error (extraction) for diosmin was performed using the example of Detralex tablets. The sample preparation error was 8%. Conclusion. The values components of error for reference-specific absorbance value and sample preparation error for diosmin quantitation were determined (as exemplified by the study of Detralex tablets). Calculation algorithms can be used for error estimation of sample preparation for other multicomponent samples in drug quality control.

In this work, a model of the cathode spot of a vacuum arc in the framework of the drift-diffusion representation has been considered. The use of the drift-diffusion approximation eliminates the need to calculate the particle energy distribution functions and take into account various energy reactions that are not accompanied by a change in the particle charge. It has been shown that the field strength of the plasma column is significantly reduced. The column is surrounded by a space charge of slow positive ions, providing a high field strength in front of it. At the stage of the formed plasma boiler, the ionization of metal vapor occurs mainly in a thin layer in front of the ion cloud, and ion recombination prevails in the column.

Base-catalyzed reaction of 3-aroyl-6-halopyridine-3,5-dicarbonitriles with alcohols involved successive regioselective pyrrole ring fusion at the pyridine [c] side and nucleophilic substitution of chlorine. Pyrrole ring closure is the result of initial formation of furan ring with participation of the carbonyl and cyano groups, followed by iminolactone–lactam rearrangement. The reaction in anhydrous alcohol afforded 1,6-dialkoxy-4-amino-1-aryl-3-oxo-2,3-dihydro-1H-pyrrolo[3,4-c]pyridine-7-carbonitriles. If water was present in the alcohols, the products were 6-alkoxy-4-amino-1-aryl-1-hydroxy-3-oxo-2,3-dihydro-1H-pyrrolo[3,4-c]pyridine-7-carbonitriles.

The method for synthesis of zirconium oxide nanopowder in low-pressure arc plasma was developed. The physicochemical properties of the nanopowder were studied. The estimation was carried out by means of X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). The sequence and kinetics of structural transformations occurring in the specified time-temperature heating regimes have been examined using differential thermal analysis. It was shown that the particles have a nanometer size, a narrow particle size distribution and an amorphous-crystalline structure. The maximum specific surface area detected by the method of sorption of surfactants was 470 m2/g. The issues of crystallization were discussed. From comparison between the results of experimental studies from earlier works with the results obtained for zirconium oxide, it is concluded that the proposed method for producing NPs in a low-pressure arc discharge plasma is universal.

In order to achieve the design luminosity in the NICA collider, it is planned to equip it with both stochastic and electron cooling. The electron-cooling system (ECS) for 2.5 MeV consists of two coolers which cool both ion beams simultaneously. The Budker Institute of Nuclear Physics (BINP SB RAS) already built and commissioned an electron cooling system for the NICA booster, and now the high-voltage ECS for the collider is being developed. This paper describes the basic elements of the system and the status of the cooler development.

The reaction of 4-acyl-2-amino-6-chloropyridine-3,5-dicarbonitriles with aromatic thiols in 1,4-dioxane in the presence of triethylamine led to the formation of 4-acyl-2-amino-6-(arylsulfanyl)pyridine-3,5-dicarbonitriles.

The paper presents the results of numerical modeling of the ionospheric disturbances from spatially localized, midlatitude, thermospheric sources that simulate the dissipation effect of acoustic–gravity waves generated by phenomena on the Earth’s surface and in the lower atmosphere. The results of numerical calculations have shown that the range of ionospheric effects significantly exceeds the size of the region of sources of thermospheric disturbances and reaches low latitudes. In the spatial distribution of the critical frequency of the ionospheric F2 layer, it decreases directly above the thermospheric source and increases to the south of it. Negative ionospheric disturbances are due to a decrease in the partial concentration of atomic oxygen in the area of a thermospheric source. The processes of turbulent diffusion, which lead to a decrease in the concentration of atomic oxygen in the lower thermosphere, are most effective in reducing the electron concentration in the ionosphere. The developing large-scale circulation processes in the thermosphere lead to positive ionospheric disturbances, which are observed south of the source region up to low latitudes.

VEPP-2000 is the only electron–positron collider with round beams. This factor enables one to increase the beam–beam effect limit. During the 2018–2019 season, the experimental program was focused on the energy range of 550–990 MeV per beam. Data accumulation was performed using CMD-3 and SND detectors. The measured luminosity integral proved to have a record value of 68 pb–1 per detector. After connecting to the BINP injection complex in 2016, the luminosity of VEPP-2000 is limited by the beam–beam effects in the entire energy range.

The VEPP-5 injection complex, consisting of two linacs and a damping storage ring, delivers electron and positron beams to the VEPP-4M and VEPP-2000 colliders operating at BINP. Over three years of injector operation, its efficiency has significantly increased and the maximum positron-storage rate has reached 1.2 × 1010 s–1. This progress was reached through tuning the constituent machines, upgrading the accelerator technology, and deploying a new 11-MHz station of RF cavities. By the start of the next running season, a new electron gun with a significantly increased maximum current and cathode lifetime will be installed.

Anionic copolymerization of acrylonitrile with methyl acrylate under the action of the 1,4-diazabicyclo[2.2.2]octane–ethylene oxide initiating system was studied. Similarly to the anionic homopolymerization of acrylonitrile, the copolymerization is accompanied by the intra- and intermolecular chain transfer to the polymer. The influence of the copolymerization conditions on the intensity of the chain transfer leading to the formation of highly branched and hyperbranched copolymers was examined. The acrylonitrile–methyl acrylate copolymerization constants were determined: r1 = 1.25 ± 0.06 and r2 = 0.18 ± 0.07. Quantum-chemical calculations of the thermodynamic parameters of the copolymerization were made.

The results of polarimetric observations of blazar S5 0716+714, carried out with the 6-meter BTA telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences, are presented. The polarized emission microvariability of blazar S5 0716+714 was observed in the R band with an initial time resolution of 3–5 seconds. Exposures were integrated at 1-minute intervals with a total observation time of several hours over two nights. Microvariability of the polarization degree with amplitude of 3–4% was detected during 7–11 minutes and flux oscillations within 9–10% during 25 minutes. A partial synchronism of the flux oscillations and the polarization degree of this blazar was found. Possible interpretations of the detected microvariability are briefly described.

For the first time, the dependences of the strain energy and the band gap of achiral nanotubes obtained by folding monolayers of gallium(II) sulfides and selenides on their diameter have been calculated nonempirically. The calculations were performed using the CRYSTAL17 software package using an atomic basis set within the hybrid density functional theory with a thirteen-percent Hartree–Fock exchange. To take into account the dispersion interactions between the layers in the crystal, the Grimme empirical correction is included in the calculations. As a result of simulation of nanotubes with different chirality and different diameters, the minimum diameters of single-walled nanotubes, at which the integrity of chemical bonds on their outer surface is preserved, are established. It is shown that the dependence of the strain energy on the diameter satisfies the classical law of inverse squares and is the same for nanotubes of the zigzag and armchair types.

Combustion and the formation of structures and phases in a 2Co–Ti–Al system during self-propagating high-temperature synthesis in a thermal explosion are under study. It is determined that a single-phase product (a Co2TiAl Geissler compound) can be obtained in this system. Morphology, microstructure, and physical-magnetic properties of combustion products of the system are investigated.

TiC + xC composites comprising titanium carbide particles, unreacted carbon black particles, and a graphite nanofilm have been prepared by self-propagating high-temperature synthesis pressing. The fused titanium carbide particles form a robust skeleton, whose voids contain carbon black particles separated from the titanium carbide particles by the graphite nanofilm. We have examined the effect of composition and temperature on the resistivity of the TiC + xC composites. The resistivity of the composites has been shown to increase with increasing carbon content. In the temperature range 300–1300 K, the temperature coefficient of resistivity (TCR) of the TiC + 0.25C, TiC + 0.5C, and TiC + 0.75C composites is 8.9 × 10–4, 9.5 × 10–4, and 9.7 × 10–4 K–1, respectively. In the temperature range 1000–1010 K, the resistivity of the composites remains constant as a result of the ordering of the carbon sublattice in TiC.

We studied the effect of pressure in a plasma-chemical reactor on the magnetic properties of copper oxide nanoparticles. Plasma-chemical synthesis of copper oxide nanopowders was carried out using an oxygen plasma of an arc discharge at pressures of 40 Pa and 200 Pa. Transmission electron microscopy showed that the obtained samples were made up of highly agglomerated particles with average particle sizes of 31 nm and 27 nm, respectively. X-ray diffraction showed the presence of a single crystalline phase of CuO. Despite the insignificant difference in the average sizes, the nanoparticles exhibited radically different magnetic behavior. Using a vibrating superconducting quantum interference device magnetometer, it was shown that the magnetic properties of nanoparticles obtained at 40 Pa were close to the bulk material and exhibited weak ferromagnetism. The nanoparticles obtained at 200 Pa demonstrated a significant deviation from the properties of the bulk material, showed magnetic hardness, and shifts in the hysteresis loops.

This paper presents the results of studies of dissimilar butt laser welds of a thermally strengthened aluminum-lithium alloy of the Al-Cu-Li system and a titanium alloy of the Ti-Al-V system. The main variable parameter was the laser offset relative to the joint. Microstructure of the weld metal, the results of tensile tests as well as fractography of the fracture surfaces were shown. It was found that the microstructure of the aluminum alloy was of the dendrite type, and that of the titanium alloy was martensitic. An intermetallic layer was formed between them. The offset towards the titanium alloy plate reduced the thickness of the intermetallic layer from ∼400 μm (offset was 0) down to 2.5 and 0.7 μm (offset was 0.5 and 1.0 mm, respectively). Also, the transformation of its structure from brittle to ductile was observed. The ultimate tensile strength of the joints increased from 103 MPa (offset was 0) up to 213 and 272 MPa when offset was 0.5 and 1.0 mm, respectively. When offset was 1 mm, the weld metal failure occurred predominantly through the aluminum alloy. This indicates that the ultimate tensile strength of the intermetallic layer was higher than that of the Al-Cu-Li alloy. It is most likely that the mechanical properties of the intermetallic layer substantially depended on the composition of the alloying elements of the aluminum alloy.

In this paper, the structure of relative disposition of 3-vertex cutsets in a 3-connected graph is studied. All such cutsets are divided into structural units – complexes of flowers, of cuts, of single cutsets, and trivial complexes. The decomposition of the graph by a complex of each type is described in detail. It is proved that for any two complexes C1 and C2 of a 3-connected graph G there is a unique part of the decomposition of G by C1 that contains C2. The relative disposition of complexes is described with the help of a hypertree T (G) – a hypergraph any cycle of which is a subset of a certain hyperedge. It is also proved that each nonempty part of the decomposition of G by the set of all of its 3-vertex cutsets is either a part of the decomposition of G by one of the complexes or corresponds to a hyperedge of T (G). This paper can be considered as a continuation of studies begun in the joint paper by D. V. Karpov and A. V. Pastor “On the structure of a 3-connected graph,” published in 2011. Bibliography: 10 titles.

Let G be a 2-connected plane graph such that at most one of its faces is not a triangle. It is proved that G has a spanning tree without vertices of degree 2. Bibliography: 3 titles.

Charge equilibration is analyzed in the context of the dynamic approach based on the Langevin equations. The time and energy dependences of this process are discussed. Analysis of the isotopic distributions of the final products obtained in the 40Ca, 58Ni and 64Ni + 208Pb shows that charge equilibration process strongly affects the multinucleon transfer in them. Yields of the most neutron-rich heavy nuclides obtained in the 58Ni and 64Ni + 208Pb reactions are discussed.

The TiN/TiAl3/Ti2AlN composite material is fabricated in the filtration combustion mode in nitrogen of porous samples made of the TiAl intermetallic powder consolidated under thermal vacuum treatment. The weight content of each phase, which was 42% TiN, 35% TiAl3, 20% Ti2AlN, and 3% TiAl, is calculated from the X-ray phase analysis data of combustion products. The synthesized composite material containing the Ti2AlN MAX phase is good electric conductor with the metallic conduction type. Resistivity of the synthesized material is measured according to the standard 4-point dc procedure in a temperature range of 300–1300 K in vacuum 2 × 10–3 Pa. It is revealed that resistivity increases linearly from 0.35 to 1.25 μΩ m with an increase in temperature. Repeated measurements of this characteristic under subsequent heating–cooling cycles demonstrated the complete coincidence of the results, which evidences the stability of electrical properties of this material in this temperature range.

The paper presents the results of a numerical simulation of ionospheric disturbances caused by a point thermospheric heat source, which mimic the dissipation effect of acoustic-gravity waves propagating from the region of a meteorological storm. It is shown that ionospheric effects have an extensive spatial structure and are more pronounced during the day than at night. The results of numerical simulations show decreases in the critical frequency of the F2 layer (foF2) and in the total concentration of electrons to the northwest from the heat source maximum, as well as increases in the values of these parameters to the south and southeast from the heat source maximum up to the equatorial region. A comparative analysis of the daytime and nighttime disturbances of atmospheric parameters is given, and a conclusion is drawn on the causes of weakly pronounced changes in the nighttime ionosphere.

Size distributions of saltating aleurite and sand particles have been measured in a windsand flux in a desertified area in Astrakhan oblast. The distributions are approximated by a sum of lognormal distributions for the aleurite-sand and aleurite fractions. The threshold wind velocity for the total particle concentration is determined under conditions of nonintermittent saltation. It is found that the threshold velocity depends on the size of saltating particles. Empirical approximations of the total number concentration and differential particle concentration of aleurite and sand particles as functions of wind velocity are obtained.

This paper describes the experimental study of strength characteristics and the microstructure of a permanent joint of dissimilar materials (VT20 titanium alloy and V-1461 aluminum alloy), obtained by laser butt welding. Optical and electron microscopy, X-ray spectral and phase analysis, and the transmission diffraction method with the help of synchrotron radiation are all used to investigate the properties of a weld. It is shown that the laser radiation offset relative to the contact surface of dissimilar materials significantly changes the microstructure and phase composition of the intermetallic interlayer formed between the materials welded, thereby affecting the strength of dissimilar welded joints.

The polymerization of acrylonitrile under the action of the new initiating system 1.4-diazabicyclo[2.2.2]octane–ethylene oxide is studied. The polymerization initiated by this system is accompanied by the occurrence of intra- and intermolecular chain transfer to the polymer. It is found that cyclic ethers, such as ethylene oxide and tetrahydrofuran, facilitate the reaction of chain transfer, acting as catalysts, as confirmed by quantum chemical calculations. The study of the thermal behavior of the synthesized hyperbranched polyacrylonitrile samples in the temperature range of 175–350°C shows that heat release for these samples begins at lower temperatures and proceeds in a wider temperature range and with a lower intensity compared to a linear polymer.

On the basis of theoretical analysis of the rheodynamics of a powder material in the process of its indirect compaction with active action of an external friction force, the influence of this friction force on the density distribution of the material in the bulk of its sample was investigated. The advantages of the indicated compaction method over the one-side high-temperature compaction of powder materials, used most frequently in power metallurgy and in self-propagating high-temperature synthesis technologies, were substantiated.