bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of operation modes of a counter ow column of chemical isotope exchange of hydrogen with water with independent flows of water and hydrogen
Authors: Rozenkevich M. B
Published: April 2024

As a result of a theoretical analysis of the operation of a countercurrent column of chemical isotope exchange (CIE) of hydrogen with water in the mode with independent ows of hydrogen and water, it has been shown that there are temperature-dependent maximum values of the molar ratio of hydrogen and water ows at which the separating power of the column with respect to isotope mixtures protium-tritium and protium-deuterium are signi cantly reduced. Variants of the operation of the CIE column were experimentally studied under the condition that the condensate of water vapor is returned to the column from the outgoing steam-gas stream or without it. The results of the experiments agree with the theoretical analysis carried out.
Extraction properties of polyphosphorylated pyridines in nitric acid media
Authors: Turanov A. N. , Karandashev V. K. , Kostikova G. V. , Fedoseev A. M. , Artyushin O. I. , Brel V. K.
Published: April 2024

The extraction of U(VI), Th(IV), Am(III), and Eu(III) with solutions of phosphorylated pyridines from nitric acid solutions has been studied. The stoichiometry of the extractable complexes was established. In terms of their extraction ability, these compounds are inferior to bis(diphenylphosphinyl)methane, but they are signi cantly superior to carbamoylmethylphosphine oxides. An increase in the number of phosphine oxide groups in the molecules of phosphorylated pyridines leads to a signi cant decrease in their extraction ability and selectivity in the extraction of Am(III) and Eu(III) from nitric acid solutions.
Single-Position Location of a Radiation Source with a Curvilinear Motion and Allowance for Signal Period Evolution at the Reception Point
Authors: Bulychev Yu. G. , Mozol’ A. A.
Published: April 2024

A single-position method of non-bearing passive location has been developed with allowance for the periodicity of a radiated pulsed radio signal during the motion of a radiation source along a curvilinear trajectory. The method does not require the current Doppler frequency to be estimated and the measuredparameter is the time discrepancy between the periods of the emitted and received signals caused by the motion of a source. The problems of the computational correctness and accuracy of the method are discussed and practical recommendations are made. A numerical example is given.
Orientational Transition of Magnetization Under Conditions
Authors: Vlasov V. S. , Shavrov V. G. , Shcheglov V. I.
Published: April 2024

The effect of high-order uniaxial anisotropy on the nature of orientational transition of magnetizationis considered. In the geometry of normal magnetization of the medium with respect to the anisotropy axis, the energy density and the equilibrium position of magnetization are obtained depending on the magnitude of the applied field. The orientation of magnetization is considered for anisotropy from the second to the eighth even orders only. As an example, the simultaneous presence of anisotropy of the second and fourthorders is considered. For this case, an algebraic equation of the third degree is obtained for the analysis of which the Cardano discriminant is used. It is shown that in the case of a negative value of the discriminant, the dependence of the magnetization orientation on the field has a hysteresis character.
Active Notch Filters of the Fourth Order with an Adjustable Delay Band and Uneven Amplitude–Frequency Response
Authors: Denisenko D Yu. , Prokopenko N. N.
Published: April 2024

Potential structural schemes of notch filters (NFs) of the fourth order are considered. Equations for the coefficients of their transfer functions are given. A graphical interpretation of the parameters of the amplitude–frequency response (AFR) of the proposed NF is presented. An implementation example of the fourth-order NF is studied and simulated in the MicroCap 12 environment, confirming the possibility of independent adjustment of AFR unevenness in the passband and in the stopband.
Prospects for Infrared Luminescent Diagnostics of Superficially
Authors: Shilov I. P. , Rumyantseva V. D. , Ivanov A. V. , Alekseev Yu. V. , Gorshkova A. S. , Ryabov M. V. , Kovaleva A. M. , Kovalev M. I.
Published: April 2024

In this paper, we developed a promising technique for luminescent infrared (IR) diagnostics of neoplasms of visually and endoscopically accessible localization (dermatology, gynecology, dentistry) using ytterbium complexes of porphyrins. Possible mechanisms of accumulation of a pharmaceutical composition based on the ytterbium complex of 2,4-di(α-methoxyethyl)deuteroporphyrin IX (Yb-DMDP) in tumor tissues were studied. Studies on the pharmacokinetics and biodistribution of this substance in various organs and neoplasms of laboratory animals showed a significant selectivity of the accumulation of nanoparticles with ytterbium ions in tumors as early as 24 h after intravenous administration. For the purposes of luminescent IR diagnostics, a highly sensitive laser-fiber fluorimeter operating in the spectral range of 900–1100 nm was developed. Preclinical tests of the developed method of fluorescent IR cancer diagnostics were carried out and its prospects were shown.
On the Possible Half-Metallic Properties of Fe2RhZ (Z = Al, Si, Ga, Ge, In, Sn) Ferromagnetic Heusler Alloys
Authors: Erager K. R. , Baigutlin D. R. , Sokolovskiy V. V. , Buchelnikov V. D.
Published: April 2024

The possible presence of half-metallic properties in Fe2RhZ (Z = Al, Si, Ga, Ge, In, Sn) ferromagnetic Heusler alloys is ab initio studied. The calculation is carried out taking into account the exchange correlation effects using the generalized and meta-generalized gradient approximations. It is shown that the ground state of most investigated alloys is ferromagnetic ordering in the Тр model lattice. An analysis of the phase stability of the alloys showed that, in the considered approximations, most of them are stable in both the regular and inverse lattice, as well as in the three model lattices belonging to inverse-type Heusler structures with different atomic orders. It was predicted using the strongly constrained and appropriately normed (SCAN) functional that the Fe2RhSi alloy can exhibit the properties of half-metals, since it has an integer magnetic moment, a fairly high degree of polarization, and an energy gap at the Fermi level of spinup electrons.
Inverse Magnetocaloric Effect in Mn5Si3 Compound
Authors: Kuznetsov A. S. , Mashirov A. V. , Musabirov I. I. , Mitsiuk V. I. , Anikin M. S. , Kamantsev A. P. , Koledov V. V. , Shavrov V. G.
Published: April 2024

A direct method was used to study the magnetocaloric effect (MCE) for samples of the compound Mn5Si3 under adiabatic conditions in magnetic fields up to 2 T at cryogenic temperatures in the range from 25 to 125 K. According to the results of measurements, it is shown that at temperatures near the first-order metamagnetostructural phase transition from a noncollinear antiferromagnetic to a collinear antiferromagnetic state, both inverse and сonventional MCE are observed. The maximum value of the inverse MCE was ΔTad = –0.27 K at initial temperature T0 = 55 K in a magnetic field of 2 T. Conventional MCE with maximum value ΔTad = +0.23 K is observed at T0 = 70 K in a field of 2 T.
Inertial Magnetization Dynamics in Ferromagnetic Nanoparticles Near Saturation
Authors: Titov S. V. , Kalmykov Yu. P. , Kazarinov K. D. , Cherkasskii M. A. , Titov A. S.
Published: April 2024

Analytical solutions of the inertial Landau‒Lifshitz‒Gilbert equation for the longitudinal and transverse components of the magnetization of a single-domain ferromagnetic nanoparticle under near-saturation conditions are obtained. The solution method is based on simplifying the equation using the first integrals, which are determined using the analogy between the inertial motion of magnetization and the mechanical rotation of a solid. It is shown that accounting for the magnetization inertia causes the nutation at a frequency represented by means of a complete elliptic integral of the first kind. The dependence of the nutation amplitude on the external field value is discussed.
Generation of Hypersonic Oscillations in the Scheme of a Magnetostriction Transducer with Positive Feedback
Authors: Vlasov V. S. , Pleshev D. A. , Asadullin F. F. , Shavrov V. G. , Shcheglov V. I.
Published: April 2024

In this paper, we consider the problem of generation of hypersonic oscillations in the circuit of a magnetostrictive converter covered by a positive feedback circuit. A “coupling parameter” that reflects the amplification of the signal in the feedback loop was introduced. The development of magnetic and elastic oscillations in time is considered. As the coupling parameter increases, three main oscillation modes are revealed: initial relaxation, stationary self-oscillations, and chaotic self-oscillations. The effect of the coupling parameter and the damping parameter of the magnetization on the time of development and the amplitude of oscillations was studied. The characteristic values of both parameters corresponding to transitions between modes are revealed. Practical recommendations for choosing system parameters for the most efficient excitation of hypersonic oscillations are given.
Fresnel-Type Transition Zones
Authors: Zlobina E. A. , Kiselev A. P.
Published: April 2024

A family of exact solutions of the two-dimensional Helmholtz equation is constructed, which are suitable for describing wavefields in transition zones arising in Fresnel-type diffraction. As examples, in addition to wedge diffraction, high-frequency asymptotics of the field in problems of diffraction on obstacles with non-smooth curvature are considered.
Features of the formation of the nutation line in nuclear magnetic magnetometers and flow meters with flowing liquid.
Authors: Davydov V. V. , Logunov S. E. , Provodin D. S. , Davydov R. V.
Published: April 2024

The mechanism of formation of a nutation line in a flowing liquid is considered. New ones have been developed equations of motion of the longitudinal and transverse components of the magnetization vector in the nutation coil, which take into account the inhomogeneity of the magnetic field ΔH_0 in the zone of influence of the radio frequency field H_1 on the flowing liquid. The equations also take into account the nature of the change in the value of the magnetic field inhomogeneity ΔH_0 when the fluid moves along the nutation coil. The results of experimental studies of the shape of the nutation line are presented. Theoretical calculations are compared with experimental data.
Resonant excitation of acoustic vibrations spherical thin films by electromagnetic waves.
Authors: Zargano G. F. , Kharlanov A. V.
Published: April 2024

The possibility of excitation of acoustic vibrations of a spherical thin film by electromagnetic waves is considered. A comparison of the numerical and analytical solutions is given. The concept of spatial resonance is introduced. It has been shown that not only frequency is important, but also wavelength. The results obtained can be used to measure parameters of various environments and for medical purposes.
Slow motion medium for broadband lens antennas based on corrugated metal surfaces
Authors: Kaloshin V. A. , Bui Сhung Van
Published: April 2024

A slowing medium based on parallel corrugated metal surfaces. The study of the moderating properties of the medium was carried out using numerical method in the Ansys HFSS software environment. It is shown that the medium has a strong spatial natural and weak frequency dispersion. The latter circumstance allows it to be used in as a material for broadband lenses of the VHF-microwave ranges of electromagnetic waves. As an example of such use, a lens-based antenna was synthesized and analyzed Mikaelyan.
Comparison of methods for calculating superconducting integrated structures using semi-analytical calculations and in three-dimensional numerical modeling programs
Authors: Khan F. V. , Atepalikhin A. A. , Filippenko L. V. , Koshelets V. P.
Published: April 2024

Modeling of superconducting integrated structures in the frequency range was carried out 300...750 GHz by two methods: 1) using ABCD matrices associated with each element of the circuit; 2) using the Ansys HFSS program. The surface impedance values of superconducting films are calculated numerically using expressions from the Matthies–Bardeen theory. It was found that for samples with microstrip line widths less than a quarter of the wavelength, both models are in qualitative agreement with each other and with experimental data. Shown that with an increase in the width of the lines and the geometric dimensions of other structural elements, transverse modes arise, as well as curvature of the wave front propagating along the lines waves, which causes differences between the semi-analytical and numerical calculations, which coincide with the experiment for all samples.
Electromagnetic waves in a one-sided metallized tangentially magnetized bigyrotropic layer (with an example of calculating the characteristics of spin waves)
Authors: Lokk E. G. , Gerus S. V.
Published: April 2024

Without using the magnetostatic approximation, the problem of the propagation of electrical magnetic waves in an arbitrary direction in a tangentially magnetized one-sided metal sized bigyrotropic layer. It is shown that in this problem Maxwell’s equations reduce to differential equation to which the biquadratic characteristic equation corresponds equation with four roots k_x21, –k_x21, k_x22 and –k_x22, describing the distribution of the wave in the cross section layer. A dispersion equation is obtained that describes waves with real values k_x21 and k_x22. Based on this equation, the characteristics of spin waves in a one-sided metallized ferrite plate (which is a special case of a bigyrotropic layer) were calculated for frequencies above the ferromagnetic resonance frequency. It was found that for these waves the quantity k_x21 can take both real and imaginary values, and the quantity k_x22 can only take real values. It was discovered that at a certain frequency the spin wave has an isofrequency curve that is practically no different from a straight line.
The influence of nonlinearity on a singular point in a system of coupled Duffing oscillators
Authors: Temnaya O. S. , Safin A. R. , Kravchenko O. V. , Nikitov S. A.
Published: April 2024

The influence of nonlinearity on the displacement of a singular point in a system of two connected Duffing oscillators when coupling coefficients and insertion losses change. It is shown that the displacement of the singular point when the nonlinearity coefficient changes is accompanied by a decrease in the amplitude of the excited oscillations and a shift in the resonant frequency. The threshold values of the nonlinearity, coupling, and insertion loss coefficients at which a singular point occurs are numerically found. It is shown that an increase in the nonlinearity coefficient leads to a decrease in the threshold value of the insertion losses required for the formation of a singular point.
Activation of a new landslide process on Bureya according to interferometric measurements by the PALSAR-2 radar
Authors: Zakharova L. N. , Zakharov A. I. , Nikitov S. A.
Published: April 2024

Based on the results of processing an interferometric pair of radar images with synthesized aperture (SAR) L-band PALSAR-2 taken over the territory of the Bureya landslide in May 2019 and May 2020 from the ALOS-2 satellite, a new unstable surface area was discovered. Rated the average monthly rate of soil displacement is up to 1 cm/month along the surface of the slope at the site of the formation of a new separation wall. It was noted that interferometric processing of archival data had not previously revealed any movements of the slope surface in this place. The most possible reason for the activation of the landslide process in the new area has been identified: a violation of stability as a result of the collapse of the underlying landslide body in December 2018.
Flow of high-energy positive oxygen ions from plasma onto the substrate in a pulsed magnetron discharge with a hot target.
Authors: Kolodko D. V. , Kaziev A. V. , Ageichenkov D. G. , Lisenkov V. Yu.
Published: April 2024

A group of high-energy positive O^+ ions was detected in a plasma flowhigh-current pulsed magnetron discharge with a hot target in an Ar/O_2 gas mixture. The mechanism for the formation of accelerated O^+ ions may be the conversion of accelerated ones in the cathode layer of negative ions O^– → O^+ in the processes of charge exchange or ionization by electron impact.
Dissipation-free transport and field emission of electrons in 2D carbon heterostructures with a quantum barrier.
Authors: Yafarov R. K. , Shabunin N. O.
Published: April 2024

The influence of the thickness of a tunnel-thin charge carrier-depleted carbonlayer in an enriched non-crystalline carbon matrix for dissipative transport andfield emission of electrons. It has been established that the “geometric” increase in self-energy electrons increases the transparency of potential barriers to dissipative transport in the heterostructure and at the solid-vacuum interface. It has been shown that the introduction of a quantum barrier into the carbon matrix increases the transverse current and rectifying properties of heterostructures, increases the field current density and the steepness of the current-voltage characteristics.
Method for Calculating the Probabilities of Bit Errors in Radio Signal Reception with QPSK-Modulation in the Presence of Interference with Linear Frequency Modulation
Authors: Zvonarev V. V. , Popov A. S.
Published: April 2024

Based on the developed methodology for analyzing the noise immunity of receiving radio signals with quadrature phase shift keying (QPSK), the probabilities of a bit error in the presence of interference with linear frequency modulation were calculated and compared with the influence of harmonic interference. A technique is presented without calculating the probability of correct reception, using conditional transition probabilities between positions of the signal constellation, which has no restrictions on signal and interference levels.
Interaction of a Relativistic Electron Beam and Electromagnetic Field in a Terahertz Cherenkov Generator with a Bragg Reflector
Authors: Deichuli M. P. , Koshelev V. I. , Petkun A. A. , Chazov V. A.
Published: April 2024

A 2.5D hybrid model is used to numerically study the interaction of a beam with a current of 2.5–7.5 kA and an electron energy of 345–510 keV and terahertz (364–368 GHz) electromagnetic field. It is shown that Bragg reflectors in an electrodynamic system with an overmode ratio of 49 make it possible to significantly suppress backward radiation and multiply increase the radiation power in the direction of the electron beam. Radiation pulses with a power of up to 330 MW are obtained in calculations with disregard of heat loss in the presence of a guiding magnetic field of 6 T.
Comparative Analysis of Microservice and Serverless Technology
Building Automatic Design Systems for Calculating the Instability
of the Static Mode of Nonlinear Electronic Circuits
Authors: Gridin V. N. , Anisimov V. I. , Vasiliev S. A.
Published: April 2024

Methods for constructing distributed automation systems for circuit design to calculate the instability of the coordinates of the operating points of the static mode of nonlinear electronic circuits were considered. Two-terminal networks of type R and transmission parameters of dependent sources, as well as characteristicsof external influences (temperature, radiation, etc.) are taken as components that change under the influence of external factors. To solve the problem of calculating the instability of the coordinates of the operating points of the static mode of nonlinear electronic circuits, a technique is proposed based on the use of an auxiliary circuit, which is constructed by transposing the description of the original circuit. The features of the organization of serverless and microservice architecture for building circuit design automation systems are analyzed. The multitenant design of a microservice information system environment is described. The mechanismof operation of the service as a service is presented to ensure the operation of the business logic of the server component.
Creation of High-Power Technological Nanosecond Frequency-Pulse
Solid-State Lasers: Problems and Solutions
Authors: Rogalin V. E. , Krymskii K. M.
Published: April 2024

A review analysis of the problematic aspects of creating high-power nanosecond frequency-pulse solid-state lasers for use in various technological fields, including the electronics industry, has been carried out. Considered installations with various pumping methods (lamp and diode) in the frequency (about 100 Hz) of generation in the micron region of the infrared range. The possibilities of increasing the energy potential of influencing pulses in master oscillator-amplifier circuits, including two-pass amplification, are analyzed. Discussed possibilities and prospects for the use of lasers with active elements (AEs) on glass, as well as the synthesis of large-sized garnet single crystals with an admixture of rare earth elements and opticalceramics for the production of AEs.
Dependence of Pinus sylvestris (Pinaceae) Radial Growth on Meteorological Conditions and Aerotechnogenic Pollution (Data on the North-West of the Murmansk Region)
Authors: Romashkin I. V. , Genikova N. V. , Kryshen A. M. , Moshnikov S. A. , Polikarpova N. V.
Published: April 2024

Abstract—We studied the influence of meteorological factors and aerotechnogenic pollution on the radial growth of Scots pine (Pinus sylvestris L.) depending on the distance from the mining and metallurgical combine “Pechenganickel” (Nikel, Murmansk region). According to the content of the main polluting elements (S, Ni and Cu) in the forest litter, we identified three zones of the pollution gradient – control, buffer and impact zones. We found a significant weakening of pine stands in the impact zone due to the integrated effect of – long-term exposure to pollution (since the 1970s) and unfavorable weather events in the mid-1980s. As the emission decreased over the period 1988–2018, we observed the significant increase (up to 44%) in the radial increment of P. sylvestris in the impact zone and no meaningful changes in control and buffer ones. Further, the radial increment of trees in the impact zone reached and even exceeded the values in control conditions, despite the relatively high age of the studied trees. This indicated the high adaptive capacity of P. sylvestris.
Plant Community Transformations in Desert Rangeland Ecosystems – Evidence from the North-Western Caspian Lowland
Authors: Rybashlykova L. P. , Turko S. Yu.
Published: April 2024

Abstract—The article presents the results of long-term monitoring of successions, and the production dynamics in desert rangeland phytocoenoses over an 8-year period (2014–2021). It shows the current state of vegetative cover of the Chernozemelskaya sandy plain (north-west of the Caspian lowland, Republic of Kalmykia) following forest reclamation of fine-grained sands, carried out in the 1970s–1990s. The centers of soil deflation (aeolian erosion) differed by the degree of soil and vegetative cover transformation and the methods of the reclamation of open sands. Currently, a secondary vegetative cover has been formed on the previously identified deflation patches. The expansion and evolution of the current species composition suggests the development of secondary succession. The features of the synusial structure of desert phytocenoses reflect the state of plant communities. The relationship of the productivity of model pastures (shrub Callygonum aphyllum, subshrub Krascheninnikovia ceratoides, herbaceous species Stipa lessingiana, Artemisia lerchiana, Alyssum deserforum, Bromus tectorum, Carex stenophylla, Koeleria macrantha, Poa bulbosa) with precipitation in warm and cold periods of the growing season is analyzed. Under changing temporal and spatial climate dynamics, the successional processes are greatly influenced by wildfires and anthropogenic impact. It has been established that secondary successions under heavy transformation of the agro-pasture landscape develop more slowly. Thus, the natural and landscape environment of the current deflation centres in the rangelands of the North-Western Caspian region is an important factor determining the direction of succession.
Individual Morphometric Characters and Productivity of Plantago maxima (Plantaginaceae) in the South Siberia (Republic of Khakassia)
Authors: Pimenov A. V. , Efremov S. P. , Sedel’nikova Т. S.
Published: April 2024

Abstract—Phytocoenotic and morphological features, as well as the productivity of the giant plantain (Plantago maxima Juss. ex Jacq.) in typical floodplain landscapes of southern Siberia were studied. The coenopopulations of P. maxima growing in natural and reclaimed areas of the Bely Iyus River valley in the Shirinsky and Ordzhonikidzevsky districts of the Republic of Khakassia were assessed. Under contrasting environmental conditions, in associations with significant share of P. maxima its productivity was 8.2 ± ± 0.58 kg × 102∕ha of air-dry, and 7.7 ± 0.54 kg × 102∕ha of oven dry aboveground phytomass. P. maxima share of the total phytomass varies from 5 to 15% in mesophytic associations with high species diversity on well-drained soils, and from 40 to 80% in xerophytic associations confined to mounds with sandy, sandy-gravelly or pebbly sandy soils. In P. maxima, the size and variability of vegetative organs increase in plants growing in more moist environments, while in drier habitats, the generative structures increase in the size and variability.
Phytochemical Features of Malabaila dasyantha (Apiaceae) Aerial Parts
Authors: Mammadova Husniya Gara
Published: April 2024

Malabaila dasyantha (C. Koch) Grossh (Apiaceae) is one of the species widely used in folk medicine. However, scientific research of this species has not been carried out, and almost no information on it is found in academic scientific databases. The new distribution areas of M. dasyantha were discovered in Gadabay district, Azerbaijan. It was determined that the plant belongs to the xerophytic ecological group. The chemical composition of the species was studied, focusing on the isolation and elucidation of phytochemical structures. The aerial parts of Malabaila dasyantha were finely cut and dried at ambient conditions. The mixture of extractive substances was obtained through three consecutive extractions with acetone, each 3 days long. The resulting acetone was filtered and evaporated on a water bath, resulting in a yellow resin with a 7% yield. The resin was then dissolved in CHCl3 and chromatographed over a column of neutral Al2O3 with elution by hexane, hexane + benzene, benzene, benzene + chloroform, chloroform, and chloroform + ethanol, in different ratios. Each fraction had a volume of 100 mL, and the separation and isolation process was carried out using column (silica gel) and thin-layer chromatographic methods. The structural elucidation of the purified compounds was based on infrared spectroscopy, ultraviolet, 1H and 13C-NMR data, and compared with those previously reported in the literature. The isolated compounds from the acetone extracts of M. dasyantha were identified as scopoletin (4.3%), oxypencedanin (2.6%), isoimperatorin (3.5%), and columbianetin (2.5%). These findings may have potential applications in the fields of medicine and pharmacology. Further studies are needed to fully explore the potential of these compounds and their therapeutic properties.
Interpopulation Variability of Polyphenol Concentration in the Leaves of Spiraea aquilegifolia (Rosaceae) from the Republic of Buryatia
Authors: Kostikova V. A. , Imetkhenova O. V. , Petrova N. V.
Published: April 2024

Abstract—Composition and content of flavonoids and phenol carboxylic acids in the leaves of Spiraea aquilegifolia Pall. from natural populations of the Republic of Buryatia (Western Transbaikalia) are given in the article. Aqueous ethanol (40%) extracts from raw materials were used for chromatographic study of phenolic compounds. The analysis of phenolic compounds was carried out on an analytical High-Performance Liquid Chromatography (HPLC) system consisting of an Agilent 1200 liquid chromatograph (USA) with a diode array detector, an autosampler, and a system for collecting and processing chromatographic data ChemStation. At least 24 phenolic compounds were identified in aqueous ethanol extracts from Spiraea aquilegifolia Pall. leaves by HPLC. Three acids (chlorogenic, p-coumaric and p-hydroxybenzoic) and six flavonols (hyperoside, isoquercitrin, avicularin, astragalin, quercitrin and kaempferol) were identified among them. Flavonols hyperoside (2.9–8.2 mg/g), avicularin (3.0–5.8 mg/g) and isoquercitrin (0.8–2.5 mg/g) are the main substances in aqueous ethanol extracts from leaves. Plants from populations located at the northern distribution limit in the Western Transbaikalia have a higher content of phenol carboxylic acids (near the village Koma) and flavonols (near the village Klyuchi). Plants from populations located to the eastern limit (near villages Kusoty and Zagan) have the lowest concentration of identified phenolic compounds. A high and very high level of interpopulation variability of the studied biochemical parameters has been established. This can be explained by the functional significance of the identified compounds and their active participation in general metabolic processes in the plant. The content of identified free phenolic acids and flavonols in S. aquilegifolia was characterized by medium and high levels, compared to other studied Spiraea species. This confirms the prospects for further study of the composition of phenolic compounds of S. aquilegifolia.
Developmental Characteristics of Sorbus (Rosaceae) Species under Introduction in the Republic of Karelia
Authors: Platonova E. A. , Magerramova E. M. , Timohina T. A. , Sergienko L. A.
Published: April 2024

Abstract—For twelve years, 14 species of the genus Sorbus L. are growing of in the Botanical Garden of Petrozavodsk State University (South Karelia). They are characterized by a variety of ornamental features – the leaf shape and dissection, flowers, autumn coloring of leaves and fruits. The studied species have different geographical origin: Sorbus americana Marshall and S. decora (Sarg.) C.K. Schneid. are native to North America, S. aria (L.) Grantz, S. mougeotii Soy.-Will. et Godr., S. sudetica (Tausch) Dluff, Nees et Schauer, S. intermedia (Ehrh.) Pers., S. bristoliensis Wilmott, S. × thuringiaca (Ilse ex Nyman) Schonach. – to Europe, S. eburnea McAll., S. koehneana C.K. Schneid., S. amurensis Koehne., S. cashmiriana Hedl., S. sambucifolia (Cham. et Schltdl.) M. Roem – to East Asia, and S. caucasica Zinserl. – to Central Asia. The studied plants have been grown from seeds received in 2010–2015 from the botanical gardens of Russia and abroad. 14 species flowered and fruited for the first time in 2021–2022. Annual shoots of all studied species fully mature by the end of the season. Botanical gardens located at different latitudes provide with data on the cultivated Sorbus species, so it is possible to compare the duration of ontogenetic stages and the dates of the main phenological phases, and to draw preliminary conclusions on the influence of climatic factors on the ontogenetic and seasonal development of plants. The dates of the beginning of the spring vegetation from the middle taiga to Ufa and Stavropol vary by three weeks, and the end of shoot growth – by two months. Along latitudinal gradient from Stavropol to Apatity, the first flowering date varies from the middle of May to the end of July. In the northern regions, the growing season of most of the studied species is shorter than in the southern. A species-specific sequence of seasonal development was revealed: early onset of phenophases in S. sambucifolia, and the latest in S. caucasica, S. bristoliensis, S. eburnea, S. × thuringiaca. According to the first results of a comprehensive assessment of adaptation and viability, all studied Sorbus species are promising as urban greening plants and suitable for further cultivation in southern Karelia.
Self-Diffusion of Ferulic and Sinapic Acids in the Binary Carbon Tetrachloride–Acetone-d6 System
Authors: Golubev V. A. , Gurina D. L.
Published: April 2024

1H NMR with a pulsed magnetic field gradient method are used to measure the coefficients of self-diffusion of ferulic and sinapic acids in binary carbon tetrachloride–acetone-d6 solvent at temperatures of 278 and 298 K. Data show that the acids’ coefficients of self-diffusion grow along with the concentration of acetone-d6 and temperature. It is shown that the effective hydrodynamic radii of acids do not depend on the composition of the binary solvent within the experimental error. In light of molecular association, this behavior can be explained by the competition between two processes: acid–acetone heteroassociation and acid–acid self-association.
Thermochemistry of the Dissolution of Tetra-4-carboxymetallophthalocyanines in Aqueous Solutions of KOH at 298.15 K
Authors: Krutova O. N. , Maizlish V. E. , Lytkin A. I. , Chernikov V. V. , Volkov A. V. , Fedotova A. E. , Krutov P. D.
Published: April 2024

Complexes are obtained of tetra-4-carboxyphthalocyanines with copper and zinc that are insoluble in water. Standard enthalpies of formation of the compounds are calculated according to additive groups based on group systematics with a Benson-type classification of fragments that considers the influence of the primary environment of atoms. Thermal effects of the dissolution of crystalline tetra-4-carboxymetallo-phthalocyanines in aqueous solutions at different concentrations of KOH (0.002 to 0.02 mol/L) at 298.15 K are determined via direct calorimetry. The standard enthalpies of formation are calculated for products of the dissociation of complexes of tetra-4-carboxyphthalocyanines with copper and zinc in aqueous solutions.
Effect of Different Factors on Predicting Constants of Acidity of Low-Molecular Organic Compounds by Means of Machine Learning
Authors: Matyushin D. D. , Sholokhova A. Yu. , Buryak A. K.
Published: April 2024

A study is performed of the effect the way of standardizing the molecular structure and parameters of calculating molecular fingerprints has on the accuracy of predicting constants of acidity. It is shown that standardization (i.e., the choice of the tautomeric form and the way of writing the structure of the molecule) using OpenEye QuacPac gives the best results, but the RDKit library allows comparable accuracy to be achieved. It is established that how the charge state is chosen has a great effect on the accuracy of predictions. The accuracy of predictions depending on the radius (size of substructures) of circular molecular fingerprints is studied, and the best results are achieved using radius r = 2. A random forest, a machine learning algorithm, is used. It is also shown that the use of support vectors ensures fairly high accuracy when optimizing hyperparameters.
Kinetics of the Oxidation of Zn55Al Alloy with Molybdenum in the Solid State
Authors: Radjabova Sh. G. , Ibrokhimov P. R. , Ganiev I. N. , Obidov Z. R.
Published: April 2024

Results are presented from studying the kinetics of oxidation of Zn55Al alloy with molybdenum in the solid state. Kinetic parameters of the oxidation of alloys in the 523–623 K range of temperatures are established. It is shown that the behavior of the alloys with a third component differs considerably from the one observed during the oxidation of the binary alloy, with molybdenum additives in amounts of 0.01–0.1 wt % greatly reducing the oxidizability of Zn55Al alloy. Protective films of oxides Al2O3, ZnO, ZnAl2O4, Al2O3·Mo2O3 form during the oxidation of hard alloys.
Super Hydrophobization of the Surface of Aluminum Alloy with Organic Acids to Protect Against Atmospheric Corrosion
Authors: Semiletov A. M. , Kudelina A. A. , Kuznetsov Yu. I.
Published: April 2024

The possibility is considered of obtaining superhydrophobic (SHP) protective films on surfaces of aluminum alloy D16. It is shown that laser treatment of the alloy and its subsequent modification in solutions of carboxylic and phosphonic acids results in superhydrophobization of its surface. The protective ability of the SHP coatings is determined from polarization measurements and corrosion tests in a salt spray chamber and an urban atmosphere. Electrochemical testing of samples of D16 alloy in a sodium chloride solution shows that SHP films effectively prevent its local depassivation. It is established that SHP films formed from solutions of octadecylphosphonic and stearic acids effectively prevent alloy corrosion under atmospheric conditions.
Mixed Networks of Hydrogen Bonds in an Ethylene Glycol–Ethylenediamine System
Authors: Aghayan G. M. , Balabaev N. K. , Rodnikova M. N.
Published: April 2024

Networks of hydrogen bonds in mixtures of ethylene glycol (EG) and ethylenediamine (ED) are studied and described via molecular dynamics, graph theory, and Delaunay simplices. Results are compared to data on EG–H2O and ED–H2O systems.
Processes of Complex Formation in an Fe(II)–Fe(III)–H2Sal–C2H5OH–H2O System
Authors: Davlatshoeva J. A. , Eshova G. B. , Rakhimova M. , Miraminzoda F.
Published: April 2024

Processes of the formation of coordination compounds in the Fe(II)–Fe(III)–H2Sal–C2H5OH–H2O system are studied using the Clark–Nikolsky oxidation potential at a temperature of 298.16 K and an ionic strength of the solution of 1.0 mol/L against a sulfate background. The formation of complexes of the following compositions is established: [FeHSal(H2O)5]2+, [Fe(HSal)2(H2O)4]+, [Fe(HSal)2OH(H2O)3]−, [Fe(HSal)2(OH)2(H2O)3]3−, [FeIIIFeII(HSal)2(OH)2(H2O)8]+, [FeHSal(H2O)5]+, [Fe(HSal)(OH)(H2O)4]0, [FeIIFeIII(HSal)2(OH)2(H2O)8]+. The constants of formation of all complexes are calculated via iteration of the oxidizing function, and the areas of their dominance and maximum degrees of accumulation are determined.
Experimental and Theoretical Investigation of Inclusion Complexes of β-Cyclodextrin with Fingolimod
Authors: Garibyan A. A. , Delyagina E. S. , Antipova M. L. , Odintsova E. G. , Petrenko V. E. , Terekhova I. V.
Published: April 2024

The solubilizing effect of β-cyclodextrin on fingolimod, a new generation immunosuppressant, is studied for the first time. A possible 20× increase in the solubility of fingolimod due to the penetration of the hydrophobic fragment of the drug molecule into the macrocyclic cavity of the cyclodextrin is shown. Data driven 1H NMR spectroscopy and computer modeling suggest the configuration of the resulting inclusion complexes. The constant of the complex’s stability and its energy of complexation are calculated, and the formation of hydrogen bonds between fingolimod and β-cyclodextrin is considered.
Study of the Photoreaction of Methyladamantylthione Using Chemical Nuclear Polarization
Authors: Porkhun V. I. , Kuznetsova N. A. , Savelyev E. N.
Published: April 2024

The article presents the results of our study of the mechanisms of the photoreactions of methyladamantylthione AdCSCH3 (I) using chemical nuclear polarization (CNP) effects, which show themselves in the NMR spectra. While pulsed and laser photolysis allows us to study the kinetics of death and accumulation of intermediates released from the solvent cell, the use of CNP allows us to study cell processes in detail. The elementary acts of the reaction were established and proved experimentally.
Surface Properties and Molar Volumes of Acetone–Ethanol Solutions
Authors: Dadashev R. Kh. , Dzhambulatov R. S. , Elimkhanov D. Z.
Published: April 2024

Experimental data are presented on the surface tension and density of acetone (chemically pure) and ethanol (pure for analysis) and acetone–ethanol solutions of different concentrations. The temperature dependence of density is measured with a VIP-2MR vibration density meter with a systemic error of ±0.01 g/cm3. Surface tension (ST) is measured with hanging drops on a DSA-100 KRUSS tensiometer whose systemic error is no more than 1%. Experimental measurements show the concentration dependences of molar volumes and surface tension within the experimental error are described by a linear function. Calculations of the ST isotherms according to the equation of A.A. Zhukhovitsky, obtained by assuming the surface layer and bulk phase are ideal, show the theoretical ST isotherms coincide with experimental ones within the experimental error. Calculations of the thermodynamic parameters of the surface layer show the coefficients of thermodynamic activities of the components in the surface layer are close to unity throughout the range of concentrations. Based on these results and the finite thickness of layers, it is concluded that the surface layers of ethanol–acetone solutions is ideal.
Physicochemical Properties of Lignocellulosic Materials from Ozonized Wood
Authors: Mamleeva N. A. , Kharlanov A. N. , Kuznetsova M. V. , Kosyakov D. S.
Published: April 2024

Lignocellulosic materials (LCMs) obtained after an ozone treatment of pine wood are studied via diffuse reflectance ultraviolet (DRUV) spectroscopy, Raman spectroscopy, and fluorescence spectroscopy. The Raman spectra show that ozonation degrades lignin and hemicelluloses and lowers the content of amorphous cellulose. The Raman spectra of ozonized LCMs are deconvoluted to individual components for the first time. Based on results from analyzing the Raman and DRUV spectra, it is concluded that the aromatic structures of biomass with conjugated –С=С– and С=О bonds simply degrade, while delignification with ozone is accompanied by a multiple increase in the fluorescence of the LCMs. It is shown that the luminescence spectral characteristics of LCMs are governed by the absorption of ozone, allowing us to identify the ranges of ozone consumption corresponding to the dominant degradation of lignin and polysaccharides in the biomaterial.
Molecular Mobility in Aqueous Systems of Primary Aliphatic Amino Alcohols
Authors: Arkhipov R. V. , Rodnikova M. N. , Solonina I. A. , Razumova A. B.
Published: April 2024

Self-diffusion coefficients (SDCs) of 3-amino-1-propanol (3AP), monoethanolamine (MEA), and water molecules are measured via 1H NMR using a pulsed magnetic field gradient and a stimulated echo sequence throughout a range of concentrations at temperatures of 293–333 K. It is found that the studied amino alcohols and water form a nearly tetrahedral three-dimensional network of hydrogen bonds between the molecules of the system. It is shown that this network is stable in the liquid phase, despite the mobility of the molecules that constitute the network. The mechanism of molecular mobility is studied. It is shown that the SDC of the molecules of the above amino alcohols and their aqueous solutions depends linearly on temperature. It is concluded that the molecular mobility mechanism has a pattern of activation. To verify this hypothesis and interpret the mechanism, the energies of activation are calculated for the self-diffusion of all the studied molecules in water–amino alcohol systems. The determined energies of activation for the mobility of amino alcohol molecules in aqueous systems have similar values, suggesting they undergo interactions that produce either mixed water–amino alcohol spatial networks or amino alcohol–water molecule associations in the liquid phase.
Effect of Halogen at the Divalent Sulfur Atom on the Properties of Complexes with a Chalcogen and Hydrogen Bond
Authors: Isaev A. N.
Published: April 2024

Binary complexes with a chalcogen (A complexes) and hydrogen (B complexes) bond formed by SHX molecules (X = F, Cl, Br, OH) of divalent sulfur and a water molecule have been calculated by the MP2/aug-cc-pVTZ quantum chemical method. An NBO analysis was performed for complexes of both types along with the topological analysis of electron density and decomposition of the binding energy into components. The quantum chemical calculations showed that the binding energies, interorbital interaction energies of monomers, and electron densities at the critical point (3, –1) of intermolecular contact are close in the A and B complexes. The main contribution to stabilization of the complexes is made by the electrostatic interaction; in the B complexes, however, the contribution of the charge transfer component is also significant. The dispersion energy plays a significant role in the binding of monomers in complexes of both types. According to the calculations, the interconversion of A and B complexes occurs with a very low activation barrier.
Photophysical and Photochemical Properties of Perylene–(Cyanine Dye) Dyad in the VIS–NIR Spectrum Region
Authors: Kozlov A. V. , Sizov L. R. , Revina D. V. , Rybkin A. Yu. , Goryachev N. S.
Published: April 2024

The photophysical properties of an original covalently-bonded dyad based on a perylene derivative and IR-780 cyanine dye were studied. The dyad has pronounced absorption in the NIR region of the spectrum and a strong fluorescence signal, which is weakly quenched by the influence of the perylene derivative. Upon excitation of the dyad in the absorption region of perylene, a fluorescence signal from IR-780 is detected due to the Förster energy transfer mechanism. It is shown that the dyad does not generate singlet oxygen upon photoexcitation in the NIR region of the spectrum. However, it can generate superoxide anion radicals, indicating the presence of the photoinduced electrons transfer from the dye to the perylene.
Molecular Dynamics Simulation of Diisopropyl Ether Using Various Interatomic Potentials
Authors: Kashurin O. V. , Kondratyuk N. D. , Lankin A. V. , Norman G. E.
Published: April 2024

A comparative assessment of the accuracy of determining the density and viscosity has been carried out for diisopropyl ether using the method of classical molecular dynamics using three potentials. The accuracy of determining the viscosity coefficients when using equilibrium and nonequilibrium calculation methods was also investigated.
Thermochemistry of the Dissolution of Tetra-4-(4'-carboxyphenyoxy)- and Tetra-4-(4'-carboxyphenylthio)phthalocyanines of Copper in Aqueous Solutions of KOH at 298.15 K
Authors: Krutova O. N. , Maizlish V. E. , Chernikov V. V. , Tikhomirova T. V. , Krutov P. D.
Published: April 2024

The authors obtain complexes CuPc(4-S-C6H4-COOH)4 and CuPc(4-O-C6H4-COOH)4 that are insoluble in water. The standard enthalpies of formation of these compounds are calculated using additive groups based on group systematics with Benson-type classification of fragments, allowing for the influence of the atoms’ primary environment. Thermal effects of the dissolution of crystalline phthalocyanines in aqueous solutions of various KOH concentrations at a temperature of 298.15 K were determined via direct calorimetry. Thermal effects of the stepwise dissociation of CuPc(4-S-C6H4-COOH)4, CuPc(4-O-C6H4-COOH)4 are calculated using the HEAT computer program. Standard enthalpies of formation are calculated for products of the dissociation of CuPc(4-S-C6H4-COOH)4 and CuPc(4-O-C6H4-COOH)4 in an aqueous solution.
Formation of Xenon Hydrate from a Vapor–Gas Medium
Authors: Ninenko S. I. , Zhovnerchuk E. V,
Published: April 2024

Special two-chamber setups are used to study the formation of xenon hydrates from a vapor–gas medium, depending on the volume of the chamber. The effect different parameters have on the growth of hydrates and the degree of saturation is studied. Hydrate growth conditions with saturation indices close to ideal are determined. Based on the experimental data, an estimate is made of the size of the crystalline hydrate nucleus (minimum size, 10–15 µm). It is established that for the emergence of such a nucleus from a vapor–gas medium, the required amount of steam at a temperature of 5°C is contained in a sphere 1 cm in diameter. Conditions are determined for the growth of a hydrate with saturation close to theoretical from a vapor–gas medium. It is shown that the rate of hydrate formation in a vapor–gas medium is several orders of magnitude higher than the one for liquid water. Raising the initial temperature of the vapor–gas medium increases both the rate of hydrate formation and the proportion of such hydrate.