bluuebunny/crossref_metadata_2025 huggingface dataset:
Cluster Variation for Spatially Distributed Heterogeneous Systems
Authors: Votyakov E. V. , Tovbin Yu. K.
Published: April 2024

Fundamentals of cluster variation (CV) are developed for locally heterogeneous spatially distributed systems. The theory is based on the principles of homogeneous CV in which all variants of the location of the basis cluster on a heterogeneous lattice are additionally considered when it is translated over the system. The structure of the statistical sum of homogeneous CV is shown to remain upon moving to a heterogeneous or homogeneous spatially distributed lattice. However, cofactors of the statistical sum, which previously corresponded to homogeneous clusters, must now consider all arrangements of heterogeneous sites inside each cluster. The general approach is to use a layered structure of the transitional region with variable density between vapor and fluid on a planar square lattice. Explicit expressions for a heterogeneous statistical sum of the transitional region are given on the basis of a 3 × 3 cluster. Using a 2 × 2 cluster, it is shown how an explicit equation for the equilibrium particle distribution in the transitional region can be obtained from the heterogeneous statistical sum. A gradual increase in the size of the m × n basis cluster in the transitional region converges to the exact solution.
Studying the Mechanism of the Electrocatalyic Reaction for Producing Molecular Hydrogen Using the N-Methyl-2,4,6-triphenylpyridinyl Cation According to DFT
Authors: Dolganov A. V. , Klimaeva L. A. , Muryumin E. E. , Yudina A. D. , Zagorodnova A. S. , Tankova A. V. , Boikova T. V. , Kovaleva Yu. N. , Knyazev A. V.
Published: April 2024

DFT is used to study thermodynamic aspects of the mechanism of the electrocatalytic formation of molecular hydrogen using N-methyl-2,4,6-triphenylpyridinyl cations. A structural and energetic analysis of the corresponding intermediate products is performed. It is shown that electrocatalytic formation proceeds through a stage of forming C2-protonated radical cations and their subsequent reduction.
Effect of the State of the Reactor Surface on the Characteristics of Combustion of Gas Mixtures Containing Halogen-Substituted Hydrocarbons
Authors: Kopylov S. N. , Kopylov P. S. , Eltyshev I. P. , Begishev I. R.
Published: April 2024

The influence of the reactor walls on combustion of gas mixtures containing halogenated hydrocarbons at atmospheric pressure has been studied experimentally. When the wall is contaminated with combustion products, the additional amounts of bromine or iodine that passed from it into the volume reduce the efficiency of combustion inhibition of hydrogen–air mixtures by bromine- and iodine-containing hydrocarbons (the effect was more pronounced for iodinated substances) and weakens the self-inhibition of the combustion of ethyl bromide in a mixture with air, leading to the expansion of the concentration region of flame propagation. Based on the analysis of the known kinetic data, the experimentally observed picture was explained by a diminished role of the HI regeneration cycle during the inhibition of hydrogen combustion in air by iodinated hydrocarbon and decreased rate of the reaction of brominated hydrocarbons with atomic hydrogen when additional amounts of I2 and Br2 are supplied from the reactor wall.
Formation of the Symmetry of Elution Curves in Linear Adsorption Dynamics
Authors: Larin A. V. , Polunina I. A.
Published: April 2024

The elution curves were modeled at a constant relative length of the adsorbent bed, but at different values of the b constant involving the kinetic and adsorption constants and the mobile phase velocity. The symmetry coefficients were calculated. They were revealed to be independent of the b constant at selected heights and have a functional dependence on the relative adsorbent bed length. A regularity in the formation of the symmetry of the elution curves in linear adsorption dynamics was established.
Studying the Nature of Light Flashes in the Explosive Oxidation of Hydrogen with SO2
Authors: Makaryan E. M. , Gukasyan P. S. , Arutyunyan A. A.
Published: April 2024

The reaction of hydrogen oxidation with sulfur dioxide in the region of self-ignition (T = 470–510°C and R 200 Torr) is accompanied by the formation of elemental sulfur in an explosive mode. Kinetic calculations made with the SENKIN:CHEMKIN II program are used to analyze observed flashes of light from the explosive process, based on a mathematical model describing the oxidation of hydrogen with sulfur dioxide. Characteristics of the oxidation of hydrogen with sulfur dioxide in the region of a low-temperature chain explosion are revealed.
Solubility in Ternary System NdCl3–PrCl3–H2O at 25°С
Authors: Rumyantsev A. V. , Gur’eva A. A. , German V. P. , Keskinov V. A. , Charykov N. A. , Blokhin A. A. , Kulenova N. A. , Shaimardanova B. K. , Sadenova M. A. , Shushkevich L. V.
Published: April 2024

The solubility diagram of the ternary system NdCl3–PrCl3–H2O has been studied by the method of isothermal saturation in ampules at 25°C. In the system NdCl3–PrCl3–H2O, isovalent substitution solid solutions with the miscibility gap (PrCl3)x(NdCl3)1 – x·6H2O and (PrCl3)x(NdCl3)1 – x·7H2O have been crystallized. In the system, there is one non-invariant eutonic type point, corresponding to the saturation of the solution by two solid phases.
1,3-Dimethyl-2-phenyl-1Н-benzo[d]imidazolium Iodide—A Representative of a New Class in the Family of Metal-Free Organic Catalysts: Electrochemical Properties and Electrocatalytic Activity in the Reaction of Formation of Molecular Hydrogen
Authors: Dolganov A. V. , Klimaeva L. A. , Kostryukov S. G. , Chugunov D. V. , Yudina A. D. , Kozlov A. Sh. , Zagorodnova A. S. , Tankova A. V. , Zhirnova V. O. , Tarasova O. V. , Knyazev A. V.
Published: April 2024

The electrochemical properties and electrocatalytic activity of 1,3-dimethyl-2-phenyl-1H-benzo[d]imidazolium-3 iodide (I), a representative of a new class of organic metal-free electrocatalysts, in the reaction of formation of molecular hydrogen, in the presence of acids of various strengths (methanesulfonic acid (CH3SO3H), perchloric acid (HClO4), and trifluoroacetic acid (CF3COOH)) have been studied. It is shown that the efficiency of the electrocatalytic process strongly depends on pKa of the acids used. Using gas chromatography and preparative electrolysis at half-wave potentials, it was shown that molecular hydrogen formed with high Faraday yields in all cases. The behavior of the catalytic wave on the cyclic voltammogram (CV), at various ratios of acid and catalyst concentrations in the presence of all acids is typical for the process proceeding according to a homogeneous mechanism. The mechanism of the process was studied by the density functional method (DFT), and its main intermediates were identified. The protonation of electrochemically generated radicals at the C-2 carbon atom of compound I, with the formation of a C-protonated radical cation, was shown to be the key stage of the electrocatalytic hydrogen evolution reaction (HER).
Effect of Deposition Sequence on Catalytic Activity of CrOx–ZrO2–SiO2 in Nonoxidative Propane Dehydrogenation
Authors: Golubina E. V. , Kaplin I. Yu. , Uzhuev I. K. , Gorodnova A. V. , Isaikina O. Ya. , Maslakov K. I. , Lokteva E. S.
Published: April 2024

A comparison is made of CrOx–ZrO2–SiO2 catalysts (9 wt % chromium oxide based on Cr2O3); (Cr + Zr)/Si molar ratio of 0.8) synthesized using different orders of introducing components: (i) the simultaneous precipitation of all components, (ii) the deposition of CrOx on ZrO2–SiO2 via impregnation, and (iii) the co-precipitation of CrOx and ZrO2 on SiO2. The SiO2 precursors are TEOS in methods (i) and (ii), and SiO2 produced by calcination of rice husk in (iii). The catalysts are tested in the nonoxidative dehydrogenation of propane in a flow system with a fixed catalyst bed at 500–600°С. The co-precipitation of CrOx and ZrO2 ensures high efficiency of the catalysts. At 500 and 550°C, the most efficient catalyst is CrZr/SiO2 synthesized by depositing CrOx and ZrO2 on SiO2; at 600°C, the best on-stream behavior is exhibited by CrZrSi catalyst synthesized via the simultaneous precipitation of all components. SEM/EDX, XRD, H2-TPR, and Raman spectroscopy are used to show that in the catalysts synthesized via the co-precipitation of CrOx and ZrO2, these components (which form active sites) are uniformly distributed, have close contact, and are adequately dispersed, while Cr6+ is readily reduced to Cr3+ by the hydrogen contained in the reaction medium.
GeCn Coordination Polyhedra in the Crystal Structures
Authors: Karasev M. O. , Fomina V. A. , Karaseva I. N. , Pushkin D. V.
Published: April 2024

A crystal-chemical analysis has been performed for germanium compounds whose structure includes GeCn coordination polyhedra using the intersecting sectors method and Voronoi–Dirichlet polyhedra. In the structures of organogermanium compounds, the germanium atoms have coordination numbers of 2–6 and 10 with respect to the carbon atoms. The influence of the coordination number and oxidation state of germanium atoms on the main characteristics of their Voronoi–Dirichlet polyhedra (VDP) was considered. The existence of a single linear dependence of the solid angles of VDP faces corresponding to valence and nonvalence Ge–C and Ge⋅⋅⋅C contacts on the corresponding internuclear distances was established. A stereo effect of the lone pair of electrons of Ge(II) atoms in the GeCn complexes (n = 2–6 or 10) found; it manifests itself as a displacement of the nuclei of Ge(II) atoms from the centers of gravity of their VDPs (0.15–0.58 Å) and as asymmetry of the coordination sphere. The deviation of the GeC3 complexes from planar geometry in the crystal structures was shown to be directly proportional to the displacement of the nuclei of Ge atoms from the centers of gravity of their VDP.
Effect of the Pore Structure of Nanosilicas Decorated with Cobalt and Cerium Oxides on Catalytic Activity in the Selective Oxidation of Carbon Monoxide
Authors: Rostovshchikova T. N. , Eurov D. A. , Kurdyukov D. A. , Tomkovich M. V. , Yagovkina M. A. , Ivanin I. A. , Maslakov K. I. , Udalova O. V. , Shilina M. I.
Published: April 2024

Two types of nanosilicas with different pore structures are synthesized and decorated via impregnation with cobalt and cerium oxides. Meso–microporous spherical silica particles with thin walls of SiO2 nanochannels having specific surface area and pore volume of up to 1400 m2/g and 0.8 cm3/g, respectively, are used. Macroporous three-dimensionally ordered structures based on SiO2 (so-called synthetic opals) consisting of close-packed submicron spherical silica particles with respective porosity characteristics of 11 m2/g and 0.2 cm3/g are also used. The synthesized materials are characterized via low-temperature nitrogen adsorption, X-ray diffraction, SEM, XPS, and Fourier transform IR spectroscopy, and tested as catalysts for the selective oxidation of CO in excess H2 (CO-PROX). The effect of silica, the ratio of introduced oxides, and the order of their introduction on the structure and catalytic properties of Co–Ce/SiO2 are revealed. The catalytic behavior of the synthesized materials is determined from the specificity of interactions among the metal oxides and with the silica surface.
Effect of Additions of Mixtures of Sodium Sulfite and Formic and Acetic Acid on the Photocatalytic Reduction of Water with Cadmium Sulfide Suspensions
Authors: Fedyaeva O. A. , Poshelyuzhnaya E. G.
Published: April 2024

The photochemical reduction of water with cadmium sulfide suspensions containing mixtures of sodium sulfite and formic and acetic acid solutions has been studied by electromotive force measurements and gasometry. The sulfite ions are oxidized on the anode in the sulfite–acetate suspensions; the sulfite ions and formic acid, in the sulfite–formate solutions. Hydrogen peroxide was found among the products of the photochemical reaction; it is involved in the oxidation of the radicals of sulfite ions and molecular sulfur of CdS particles and prevents the reduction of water.
Kinetics and Dynamics of Sorption of the Glucose Target Molecule by a Molecularly Imprinted Polymer
Authors: Garkushina I. S. , Panyuta A. S.
Published: April 2024

The effect of imprinting of a polymer matrix based on ethylene glycol dimethacrylate on the kinetics and dynamics of binding of the glucose target molecule has been studied. The contribution of the adsorption act to the sorption kinetics of the target sorbate by the molecularly imprinted polymer was established. Mixed-diffusion limitation of mass transfer and cooperative adsorption of glucose molecules during sorption by both imprinted and nonimprinted polymer granules were revealed. The binding rate and accessibility of sorption sites in the imprinted polymer were shown to increase, and frontal sorption occurred in a regular mode.
Size and Content Effects of Copper Nanoparticles in the Ion-Exchange Matrix for Intense Steady-State Electroreduction of Oxygen Dissolved in Water
Authors: Kravchenko T. A. , Fertikova T. E. , Golovin I. A. , Martynov A. E.
Published: April 2024

The behavior of copper ion-exchange composites with metal particles of various sizes and contents in the electroreduction of oxygen dissolved in water have been studied. The primary size effect is significant for samples with low metal capacity: the smaller the metal particle size, the higher the process rate. At the same time, for samples with high metal capacity, the process occurs at approximately the same rate on copper particles obtained using different reducing agents due to the comparable size. A secondary size effect is observed due to the collective interaction of metal particles. The size effect was taken into account along with the effect of the content of metal particles using the proposed nanosized complex, which represents the ratio of capacity and size. At the level of electronic conductivity percolation, the nanosized complex reaches the limiting value corresponding to the highest degree of development of the reaction surface, which makes it possible to increase the current to the maximum current capacity. The reduction of oxygen occurs along several routes: electroreduction on copper particles, mainly on the surface of nanocomposite grains; and autocatalytic chemical reaction with electroregenerated metal nanoparticles in the nanocomposite grains. The electroreduction of oxygen generally reaches an intense steady-state mode.
Alginate–Chitosan Polyelectrolyte Complexes As Carriers for Fluorinated Tetraphenylporphyrin in Photosensitizing Systems of Singlet Oxygen Generation
Authors: Kopylov A. S. , Aksenova N. A. , Shershnev I. V. , Timofeeva V. A. , Savko M. A. , Cherkasova A. V. , Zarkhina T. S. , Timashev P. S. , Solovieva A. B.
Published: April 2024

Water-insoluble photosensitizing (PS) systems active in the generation of singlet 1O2 oxygen are obtained by immobilizing fluorinated tetraphenylporphyrin (FTPP) from a solution in acetone on films of polyelectrolyte complexes based on sodium alginate (SA) and chitosan (CT), and on solid water-insoluble gels of alginate and chitosan. The obtained polymer PS systems are used to establish the intensity of the photoluminescence of singlet oxygen in D2O and the activity of the photocatalytic oxidation of tryptophan in water. It is shown that the photocatalytic activity in the tryptophan oxidation of fluorinated tetraphenylporphyrin immobilized on a SA–CT polyelectrolyte complex and alginate solid gel is higher than that of FTPP immobilized on chitosan solid gel. Spectral-luminescent properties of polysaccharide–FTPP systems and the surface structure of carriers are studied via atomic force microscopy to determine the mechanism of the increase in porphyrin activity when it is fixed on alginate-containing carriers. It is suggested that aspects of the supramolecular structure of solid gels are responsible for the increase in the photocatalytic activity of FTPP upon immobilization on alginate-containing polysaccharide systems.
COMPUTING LEVEL LINES OF A POLYNOMIAL ON THE PLANE
Authors: BRUNO A. D. , BATKHIN A. B. , KHAIDAROV Z. Kh.
Published: April 2024

Application of the method of computing the location of all types of level lines of a real polynomial on the real plane is demonstrated. The theory underlying this method is based on methods of local and global analysis by the means of power geometry and computer algebra. Three nontrivial examples of computing level lines of real polynomials on the real plane are discussed in detail. The following computer algebra algorithms are used: factorization of polynomials, computation of the Gröbner basis, construction of the Newton polygon, and representation of an algebraic curve on a plane. It is shown how computational difficulties can be overcome.
AUGMENTING THE TRAINING SET OF HISTOLOGICAL IMAGES WITH ADVERSARIAL EXAMPLES
Authors: LOKSHIN N. D. , KHVOSTIKOV A. V. , KRYLOV A. S.
Published: April 2024

In this paper, we consider the problem of augmenting a set of histological images with adversarial examples to improve the robustness of the neural network classifiers trained on the augmented set against adversarial attacks. In recent years, neural network methods have been developed rapidly, achieving impressive results. However, they are subjected to the so-called adversarial attacks; i.e., they make incorrect predictions on input images with added imperceptible noise. Hence, the reliability of neural network methods remains an important area of research. In this paper, we compare different methods for training set augmentation to improve the robustness of neural histological image classifiers against adversarial attacks. For this purpose, we augment the training set with adversarial examples generated by several popular methods.
AUTOMATED METHOD FOR OPTIMUM SCALE SEARCH WHEN USING TRAINED MODELS FOR HISTOLOGICAL IMAGE ANALYSIS
Authors: PENKIN M. A. , KHVOSTIKOV A. V. , KRYLOV A. S.
Published: April 2024

Preparation of input data for an artificial neural network is a key step to achieve a high accuracy of its predictions. It is well known that convolutional neural models have low invariance to changes in the scale of input data. For instance, processing multiscale whole-slide histological images by convolutional neural networks naturally poses a problem of choosing an optimal processing scale. In this paper, this problem is solved by iterative analysis of distances to a separating hyperplane that are generated by a convolutional classifier at different input scales. The proposed method is tested on the DenseNet121 deep architecture pretrained on PATH-DT-MSU data, which implements patch classification of whole-slide histological images.
USING MULTILEVEL HASH TABLES TO SPEED UP RENDERING
Authors: ZHDANOV D. D. , LYSYKH A. I. , KHALIMOV R. R. , KINEV I. E. , ZHDANOV A. D.
Published: April 2024

In this paper, we analyze realistic rendering methods in terms of their efficiency in calculating caustic and indirect illumination. As the basic approach to realistic rendering, we choose bidirectional progressive ray tracing with backward photon maps. The main factors that reduce the efficiency of this method are analyzed. It is shown that the main factor that affects its performance is slow access to photon map data. Different techniques for construction of spatial acceleration structures are considered, their advantages and disadvantages are investigated. As the main approaches, we select the regular spatial grid and binary kd tree. The spatial grid provides high-speed access to photon data at low adaptability of photon map partitioning. The kd tree is characterized by high spatial adaptability of photon map partitioning but slow access to photon data. We propose a combined solution that takes advantage of the adaptability of the kd tree and the fast data access of the spatial grid. For this purpose, the regular grid is superimposed on the kd tree constructed based on the principle of space partitioning of a photon region into geometrically identical halves. To reduce memory consumption, we propose, first, to use multilevel spatial grids superimposed on the selected nodes of the kd tree and, second, to store spatial grids in the form of hash tables in order to reduce the size of the acceleration structure. Thus, a spatial acceleration structure of a new type—a tree of hash tables—is proposed and implemented. For the spatial structure developed, we implement methods for finding the nearest photons the integration spheres of which cover the illumination point, as well as methods for finding the intersection between a ray segment and photon integration spheres. The proposed software solutions are implemented in the Lumicept software package; for some scenes, the proposed method is compared with the Lumicept method based on the binary tree. The comparison shows that our method can increase the overall speed of the rendering process by more than 40%.
TWENTY SIMILARITY FUNCTIONS OF TWO FINITE SEQUENCES
Authors: Burdonov I. , Maksimov A.
Published: April 2024

The article discusses the various numerical functions that determine the degree of "similarity" of the two given final sequences. These similarity measures are based on the concept we define of embedding in a sequence. A special case of such an attachment is the usual sub-subsequence. Other cases further require equality of distances between adjacent sub-sequence symbols in both sequences. This is generalization of the concept of a sequence segment (substring) in which these distances are unit. In addition, equality of distances from the beginning of the sequences to the first embedding symbol or from the last embedding symbol to the end of the sequences may be required. Except these last two cases, the attachment can be in a sequence several times. The literature uses functions such as the number of common attachments or the number of attachment occurrence pairs in a sequence. In addition to them, we enter three more functions: the sum of the lengths of total investments, the sum of the minima of the number of occurrences of a common embedding in both sequences and the similarity function based on the largest number of symbols of the common embedding. Intotal, 20 numerical functions are considered, for 17 of which algorithms (including new ones) of polynomial complexity are proposed, for two more functions, algorithms have exponential complexity with reduced a measure of degree. The Conclusion gives a brief comparative description of these investments and functions.
ROBUST ALGEBRAIC CONNECTIVITY
Authors: Kuruzov I. A. , Rogozin A. V. , Chezhegov S. A. , Kupavskii A. B.
Published: April 2024

The second smallest eigenvalue of a graph Laplacian is known as algebraic connectivity of the graph. This value shows how much this graph is connected. But this metric does not take into attention possible changes in graph. Note, that deletion of even one node or edge can lead the graph to be disconnected. This work is devoted to development of a metric that should describe robustness of the graph to such changes. All proposed metrics are based on algebraic connectivity. Besides, we provide generalization of some famous optimization methods for our robust modifications of algebraic connectivity. Moreover, this work contains some numerical experiments demonstrated efficiency of proposed approaches.
The Role of Lipid Domains and Physical Properties of Membranes in the Development of Age-Related Neurodegenerative Diseases
Authors: Krasnobaev V. D. , Batishchev O. V.
Published: April 2024

A growing number of studies indicate the relationship between the development of neurodegenerative diseases and the structure and lipid composition of neuronal membranes. One of the structural elements of cell membranes, which in this regard attracts special attention, are liquid-ordered lipid domains, or rafts. The study of rafts and age-related changes in the lipid composition of neuronal cells is becoming increasingly relevant and is constantly being updated. In this review, we tried to highlight the possible role of the lipid component of cell membranes, their structure, and physicochemical characteristics in the development of diseases associated with aging. The reviewed evidence supports the possible role of rafts in diseases, which lead to disruption of the functioning of neurons over a long period of time. There is reason to believe that the therapeutic effects of various molecules, such as lysolipids and gangliosides, are due to their physicochemical properties and are realized indirectly, through their influence on the organization of lipid domains in membranes. As the role of lipid domains and, in general, the mechanisms of interaction and mutual influence of lipid composition and disease development are more fully understood, this knowledge can be used to develop new therapeutic or preventive methods to combat diseases associated with aging.
Cationic Lipoaminoacid Derivatives of Diethanolamine as Potentially Membrane-Active Antibacterial Agents
Authors: Guseva M. K. , Denieva Z. G. , Budanova U. A. , Sebyakin Yu. L.
Published: April 2024

This work is aimed to develop a number of cationic amphiphiles based on amino acid derivatives of diethanolamine as potentially membrane-active antibacterial agents. The developed compounds contain two amino acid residues in the polar block and various length of aliphatic chains in the hydrophobic domain. Amphiphiles were obtained in preparative amounts sufficient to confirm their structures and perform a study of antibacterial activity. The synthesized samples based on β-Ala (4c) and GABA (4d) with an aliphatic C12 chain in the hydrophobic domain showed a promising level of antimicrobial activity (minimal inhibitory concentration, MIC, 1 μg/mL) against gram-positive (B. subtilis) and gram-negative (E. coli) bacteria. Amphiphiles containing aromatic amino acids L-Phe (6a) and L-Trp (6b) in the polar head group and C8 hydrocarbon chain are active against B. subtilis with a MIC of 1 μg/mL. The obtained data on antimicrobial activity make the selected compounds attractive for further detailed study of their mechanism of action.
Model of a Molecular Proton Sensor in Taste Cells
Authors: Sladkov K. D. , Kolesnikov S. S.
Published: April 2024

Otopetrins represents a group of membrane proteins that function as proton-selective ion channels. Existing evidence indicates that Otop1, the eponym of the family, is a likely molecular sensor of protons involved in detecting acid stimuli in taste cells of type III. Acid stimuli is believed to initiate an inward current carried by protons through receptive apical membrane to depolarize a type III cell and trigger a train of action potentials driving afferent neurotransmission. While many details of this rather complicated process have not been uncovered yet, mathematical modelling could provide a sufficient insight into sour transduction. Here we present a mathematical model for describing dynamic and transport properties of Otop1 channel. The elaborated model appropriately describes proton currents through Otop1 under different conditions, and it could be employed for further modeling of sour responses of taste cells.
Involvement of the Mitochondrial Ca2+-Independent Phospholipase iPLA2 in the Induction of Mitochondrial Permeability Transition Pore by Long-Chain Acylcarnitines
Authors: Fedotcheva N. I. , Grishina E. V. , Dynnik V. V.
Published: April 2024

It is known that activated derivatives of long-chain fatty acids acylcarnitines (LCAC) are considered the most toxic, which, along with calcium, can participate in the induction of mitochondrial permeability transition pore, involving various types of phospholipases in the complex mechanisms of pore activation. In this work, we investigated the influence of different inhibitors of phospholipases and carnitine palmitoyltransferase-1 (CPT1) on the induction of mitochondrial permeability transition pore by D,L-palmitylcarnitine (PC, C16:0). In the experiments on isolated rat liver mitochondria, the effects of PC on mitochondrial respiration rate, mitochondrial potential (ΔΨm), and mitochondrial swelling were examined. It was shown that the application of the inhibitors of carnitine palmitoyltransferase-1 (Etomoxir 2), Ca2+-dependent phospholipase cPLA2 (Aristolochic acid), or Ca2+-independent phospholipase iPLA2γ ((R/S)-bromoenol lactone (BEL) and PACOCF3) caused an increase in the critical concentrations of D,L-palmitylcarnitine (PC*) required for ΔΨm dissipation and mitochondrial swelling. The most pronounced protective effect was caused by PACOCF3 and BEL. In state 3 of respiration (ADP + Mg2+ + hexokinase), Etomoxir 2 and Aristolochic acid enhanced respiration inhibition induced by excess D,L-palmitylcarnitine and promoted dissipation of ΔΨm, while-the inhibitors of iPLA2γ prevented the dissipation of ΔΨm evoked by D,L-palmitylcarnitine and caused an increase in the rate of mitochondrial respiration. Thus, the results obtained indicate the involvement of mitochondrial iPLA2γ in the induction of mitochondrial permeability transition pore by long-chain acylcarnitines.
Characteristics of Membrane Structures of Wheat Chloroplasts
Authors: Kapustina I. S. , Gurina V. V. , Spiridonova E. V. , Ozolina N. V.
Published: April 2024

When studying the raft structures of wheat chloroplast membranes, previously identified in the 15% sucrose zone after high-speed centrifugation, an additional opalescence zone was found in the 5% sucrose region. Analysis of the composition of sterols and fatty acids of lipids in this zone in comparison with the zone of rafts and chloroplast membranes showed that raft structures may also be present in this zone. This suggests that wheat chloroplast membranes may contain two types of raft structures.
MgO STABILITY IN EUTECTIC Li2CO3–Na2CO3 AND Li2CO3–K2CO3
Authors: Tolkacheva A. S. , Konopel’ko M. А.
Published: April 2024

Research and technology studies on Molten Carbonate Fuel Cells (MCFC) are being directed at improving their performance in mode of greenhouse gas conversion for chemical energy storage. The changes in gas composition feeding MCFC demand new insulating materials to be found. In the current work, the equilibrium solubility of magnesia ceramics in air in contact with Li2CO3–Na2CO3 and Li2CO3–K2CO3 eutectic mixtures was measured at 600°С. The study shows that magnesia is completely stable in the tested melts for at least more than 270 h. Its solubility was found to increase in Li–K carbonate eutectic. Conclusions about the material stability are based on results of inductively coupled plasma atomic absorption spectroscopy of melts and scanning electron microscopy combined with X-ray diffraction employed to ceramics testing. Magnesia is recommended as an insulating material in electrolysis cells containing Li2CO3–Na2CO3 and Li2CO3–K2CO3 carbonate eutectics for the conversion of the greenhouse gas in chemical energy storage devices operating in air.
EP-823 STEEL CORROSION RATE IN MOLTEN CHLORIDES OF ALKALI METALS
Authors: Golosov O. A. , Khvostov S. S. , Staritsyn S. V. , Barybin A. V. , Pastukhov V. I. , Glushkova N. V. , Zaikov Y. P. , Nikitina E. V. , Kazakovtseva N. A.
Published: April 2024

At present, technologies are being developed for the regeneration of mixed nitride uranium-plutonium spent nuclear fuel (MNUP SNF) for the BREST-OD-300 reactor plant, including the use of a pyrochemical method of mild chlorination in alkali metal chloride melts to separate fuel from fuel rod claddings made from high radiation resistance of ferritic-martensitic steel EP-823. The paper gives the results of EP-823 static corrosion tests in KCl–LiCl and KCl–LiCl–nPbCl2 molten salts at the temperature of 500 and 650°С during 24 h. Corrosion behaviour of EP-823 steel in non-oxidized and thermal air oxidized state with oxide film thickness up to ~12.5 µm has been investigated using neutron-activation analysis. EP-823 steel samples, irradiated in IVV-2M reactor up to neutron fluence of ~2.9 · 1017 n/cm2, have been examined. It has been shown that corrosion impact of 2KCl–3LiCl and 2KCl–3LiCl–nPbCl2 molten salts on EP-823 element corrosion is selective. It has been established that EP-823 steel in 2KCl–3LiCl molten salts of eutectic composition is highly corrosion-resistant. An increase in the test temperature and the introduction of PbCl2 into the KCl–LiCl salt melt in the amount of one mole percent leads to an increase in the corrosion rate and the removal of steel corrosion products by almost two orders of magnitude. It has been established that oxide films on EP-823 steel surface does not restrain corrosion rate in 2KCl–3LiCl–nPbCl2 molten salts. The values of the constants given in Table 6, make it possible to calculate the values of the average corrosion rates of EP-823 steel and its components (Fe, Cr, Mn) in molten salts 2KCl–3LiCl and 2KCl–LiCl–nPbCl2 at various temperatures.
MOLECULAR DYNAMICS SIMULATION OF MOLTEN NiF2: STRUCTURE AND TRANSPORT PROPERTIES
Authors: Kobelev М. А. , Zakiryanov D. О. , Tukachev V. А.
Published: April 2024

Computer modeling of molten nickel fluoride was carried out using classical molecular dynamics in the temperature range 1750–1900 K. The density of crystalline NiF2 with a relative error of less than 1% verified the parameters of the pair potential obtained in the framework of the quantum-chemical approximation. The calculated radial distribution functions and coordination numbers for the Ni–F pair indicate a distorted octahedral environment of the nickel cation in the melt. In this case, a slight decrease in the nearest cation-anion distance was found in comparison with solid nickel fluoride. It is shown that the curve of the radial distribution function for the fluorine-fluorine pair near the main peak splits into two maxima. The position of the first peak at 2.67 Å is characterized by a coordination number of 5.1 and describes neighboring anions in a distorted octahedron. Whereas, the second maximum can be associated with fluorine anions located along the F–Ni–F line with a peak position at 3.83 Å, which indicates a decrease in a similar distance compared to the crystal. The coefficients of self-diffusion of ions and the viscosity of the NiF2 melt at different temperatures were calculated.
ON THE COMPOSITION OF SATURATED VAPORS AND VOLATILITY OF TETRACHLORIDES OF URANIUM AND SOME OTHER METALS (ThCl4, HfCl4, ZrCl4, TiCl4) FROM THEIR MOLTEN MIXTURES WITH ALKALI METAL CHLORIDES
Authors: Salyulev A. B. , Kudyakov V. Ya.
Published: April 2024

Based on our experimental data and those obtained by researchers, mainly employees of our Institute (IHTE UB RAS), the regularities of changes in the composition of saturated vapors and the volatility of components of molten mixtures of tetrachlorides of uranium and some other metals (ThCl4, HfCl4, ZrCl4, TiCl4) with alkali metal chlorides depending on the temperature, concentration and cationic composition of melts are discussed. It is noted that the dissolution of UCl4 as well as other tetrachlorides in molten alkali metal chlorides is accompanied by complexation, manifested in a sharp decrease in the volatility of the corresponding tetravalent metal chloride and its content in saturated vapors. The strength of the complex chloride anions of polyvalent metals formed in melts increases significantly with a decrease in their concentration, replacement of the solvent salt in the series from LiCl to CsCl and temperature. As a result, the volatility values of UCl4, ThCl4, HfCl4, ZrCl4, TiCl4 and the composition of vapors above their solutions in ionic melts vary greatly. At the same time, according to the experimental data hafnium, zirconium and titanium tetrachlorides (especially TiCl4), which are much more volatile in the individual state, have higher volatility and content in saturated vapors over solutions in molten alkali metal chlorides.
MODIFICATION OF LANTHANUM OXIDE La2O3 ON THE STRUCTURE OF SUPRASTRUCTURAL UNITS IN ALKALI BORATS
Authors: Vorontsov B. S. , Moskvin V. V. , Babina I. A.
Published: April 2024

It shows a significant change in structurally sensitive properties in the experiment of modifying a melt (or glass) of the B2O3–Na2O system with lanthanum oxide La2O3 with the destruction of superstructural units when lanthanum atoms hit, since small additions of rare earth metal oxides lead to a significant change in the properties of alkali borate melts. Molecular models of some of the superstructural units, the structure and properties of which were calculated by semi-empirical quantum chemical methods with MNDO and PM7 parameters: as a result of the optimization procedure, both methods lead to models that are qualitatively close, but differ in bond lengths, and practically the same value of heat of formation. The superstructural unit of the considered type is preserved, while its characteristics change: the volume occupied by it increases, the newly formed bond is less strong and its ionic degree is greater.
LOW-TEMPERATURE ELECTROLYTIC PRODUCTION OF Al-REM ALLOYS IN CRYOLITE MELTS
Authors: Rudenko A. V. , Tkacheva O. Yu. , Kataev A. A.
Published: April 2024

The process of electrolytic production of Al–Y and Al–Sc alloys in an electrolyte based on potassium cryolite KF–NaF(10 wt %)–AlF3 with a cryolite ratio (CR) of 1.5, containing Al2O3, Sc2O3, or Y2O3 oxides, in a cell with vertical electrodes has been studied. The Fe–Ni–Cu alloy served as an inert anode. The wetted cathode was a graphite plate coated with the aluminum diboride. The electrolysis was carried out at a cathode current density of 0.2 A/cm2 and a temperature of 830°C. The Al2O3 mass was calculated based on the value of the current efficiency of 60%. The Sc2O3 additive was introduced into the melt in an amount of 1 wt %. The mass of the Y2O3 additive was chosen based on its solubility in the melt under study. For this, the influence of Y2O3 additives on the liquidus temperature of the quasi-binary mixture [KF–NaF(10 wt %)–AlF3 (KO = 1.5)]–Y2O3 was determined and it was found that, in contrast to Sc2O3 additives, which lower the liquidus temperature of the cryolite melt, small additions of Y2O3 lead to its sharp increase. It has been found that the efficiency of the electrolytic reduction of Y2O3 is 10 times higher than that of the aluminothermic reduction. Other things being equal, the efficiency of the electrolytic reduction of Y2O3 is higher than that of Sc2O3. Alloys Al–Y and Al–Sc with a REM content of 0.6 wt % have been obtained. However, the time to reach the maximum recovery of yttrium significantly exceeds the time to recover scandium. Metallographic studies of the obtained alloys indicated the presence of Al3Sc and Al2Y intermetallic compounds. A conclusion is made about the fundamental possibility of low-temperature electrolytic production of Al-REM alloys in cryolite melts based on potassium cryolite in vertical cells with an inert metal anode and a wettable cathode.
SYNTHESIS AND STRUCTURE OF FOUR TiZrVNb AND FIVE-COMPONENT TiZrHfVNb REFRACTORY HIGH-ENTROPY ALLOYS
Authors: Sipatov I. S. , Petrova S. А. , Ignatieva E. V. , Rempel A. A.
Published: April 2024

High-entropy alloys attract researcher’s attention due to the presence of a set of new properties. The paper considers the factors affecting the structure of high-entropy alloys (HEAs) based on the elements Ti, Zr, Hf, V, and Nb. The structure data of four-component Ti25Zr25V25Nb25 and five-component Ti20Zr20Hf20V20Nb20 alloys, which were obtained under the same melting and cooling conditions in an arc furnace, are presented. The data of the EDX analysis showed that the chemical composition of the alloys corresponded to the nominal one. Analysis of micrographs of the ingots surface allows us to conclude that the applied melting mode led to overheating of the four–component alloy, but not for the five-component one. It was experimentally found that the primary formation of the four-component alloy occurs faster than that of the five-component one, but further remelting under overheating conditions leads to multiphase structure formation. The maximum content of BCC solid solution (98%) in Ti25Zr25V25Nb25 alloy was achieved during the first remelting, another phase was FCC solid solution (2%). The maximum content of BCC solid solution (95%) in Ti20Zr20Hf20V20Nb20 alloy was obtained by repeated remelting, BCC, HCP solid solutions, and the Laves phase were presented in the amount of 3% or less. The crystal lattice parameters of the BCC main phases for the Ti25Zr25V25Nb25 and Ti20Zr20Hf20V20Nb20 alloys were 3.270 and 3.362 Å, respectively. It was established that to obtain refractory HEAs with a single-phase structure it is important both fulfilment of thermodynamic conditions and correct choice of time-temperature conditions of melting and crystallization for each specific alloy composition.
Application of Protective Technological Coatings under Low-Temperature Deformation of Hard-to-Deform Alloy Blanks
Authors: Polyanskii S. N. , Butakov S. V. , Antimonov A. M. , Ol’kov I. S. , Aleksandrov V. A.
Published: April 2024

Protective technological coatings for low-temperature deformation of semi-finished products and products from hard-to-deform alloys (titanium, zirconium, etc.) are considered. The process of low-temperature isometric product deformation made of the VT6 alloy, friction, and the separating properties of protective technological coatings are studied by compression of ring samples. Laboratory studies and industrial tests of pilot batches of coatings are carried out. Recommendations on the use of protective technological coatings are presented
Temperature Regimes of a Kamaz-5320 Vehicle Gearbox Bearing Unit to Ensure Testability
Authors: Timashov E. P. , Pastukhov A. G.
Published: April 2024

The results of analytical study on the temperature regimes of the gearbox bearing units are given, and their diagnostic criteria are substantiated. We prove experimentally the possibility of practical application of the automatic thermal diagnostics based on the study of the thermal regimes of the bearing unit.
Application of a Pantographic Design Obtained by the Method of SLM Printing and Study of the Influence of Postprocessing with Application of Damping Coatings
Authors: Fozilov T. T. , Babaytsev A. V. , Zaitsev A. A. , Lopatin S. S.
Published: April 2024

To deal with residual stresses that arise after the application of the selective laser sintering method, in this article the heat treatment method according to the State Standard and vibration tumbling in a drum with ceramic “chips” are chosen. During operation, various vibrations occur, which lead to the destruction of the structure. To deal with vibrations of this kind, it is proposed to apply coatings to the structure. Such coatings increase the resistance to oxidation, corrosion, etc. In addition, they absorb vibrations (damping), thus removing resonance. At the same time, the service life of a coated product relative to an uncoated part is guaranteed to be 5–20% higher.
Scientific Foundations for the Aerohydrodynamic Grinding of Lignocellulosic Raw Material under Steam Explosion
Authors: Ganiev O. R. , Grishnyaev I. N. , Ganiev S. R. , Kurminev D. V.
Published: April 2024

The results of studies aimed at improving the methods and equipment for the preliminary treatment of lignocellulosic raw materials by means of steam explosion are presented. The scientific basis for the outflow of superheated steam from a reactor in the course of detonation boiling of a liquid is described. Based on theoretical and experimental studies, it is shown that, in order to provide an increase in the efficiency of the steam explosion energy, it is appropriate to mount an aerohydrodynamic grinder (AHG) containing a Laval nozzle at the reactor outlet.
Protective and Tribological Properties of Sulfonate Greases
Authors: Samusenko V. D. , Tatur I. R. , Kal’yanova O. A. , Strel’nikova S. S. , Buyanovskii I. A.
Published: April 2024

The protective properties and temperature resistance of sulfonate greases based on petroleum oil KS-19 have been assessed. Highly alkaline calcium sulfonates of Russian and foreign production are used as thickeners for such greases. Sulfonate greases have been shown to have good protective properties. It has been established that the ability of sulfonate greases to prevent corrosion depends on the protective properties of calcium sulfonate used as a thickener. Based on the totality of the indicators obtained, the grease based on the Russian-made K-314 thickener has the best properties; in temperature resistance, it is superior to the sample on the foreign thickener Lubrizol 86 GR, and in terms of protective properties, it is on the same level with it.
On the Nature of the Rapid Color Changes of the UX Ori Star RY Lupi at Deep Minima
Authors: Dmitriev D. V. , Grinin V. P.
Published: April 2024

We propose an explanation for the rapid color changes on the color–magnitude diagrams observed by Gahm et al. in the T Tauri star RY Lup during its deep minima. Our calculations have shown that the hot accretion spot on the stellar surface in combination with the inhomogeneous structure of the gas–dust clouds obscuring the star can be responsible for these changes. The observed rate of of the color changes allows one to estimate the velocity of the screen across the stellar disk =100 km s-1. This velocity is close to the typical gas velocities near T Tauri stars.
Maximal Mass Neutron Star as a Key to Superdense Matter Physics
Authors: Ofengeim D. D. , Shternin P. S. , Piran T.
Published: April 2024

We propose a universal approximation of the equation of state of superdense matter in neutron star (NS) interiors. It contains only two parameters, the pressure and the density at the center of the maximally massive neutron star. We demonstrate the validity of this approximation for a wide range of different types of equations of state, including both baryonic and hybrid models. Combined with recently discovered correlations of internal (density, pressure, and speed of sound at the center) and external (mass, radius) properties of a maximally massive neutron star, this approximation turns out to be an effective tool for determining the equation of state of superdense matter using astrophysical observations.
New Interstellar Extinction Maps Based on Gaia and Other Sky Surveys
Authors: Gontcharov G. A. , Marchuk A. A. , Khovrichev M. Yu. , Mosenkov A. V. , Савченко S. S. , Il’in V. B. , Poliakov D. M. , Smirnov A. A.
Published: April 2024

We present new three-dimensional (3D) interstellar extinctionmaps in the V and Gaia G filterswithin 2 kpc of the Sun, a 3D differential extinction (dust density) map along the line of sight in the samespace, a 3D map of variations in the ratio of the extinctions in the V and Gaia G filters within 800 pcof the Sun, and a 2D map of total Galactic extinction through the entire dust half-layer from the Sun toextragalactic space for Galactic latitudes |b| 13◦. The 3D maps have a transverse resolution from 3.6to 11.6 pc and a radial resolution of 50 pc. The 2D map has an angular resolution of 6.1 arcmin. Wehave produced these maps based on the Gaia DR3 parallaxes and Gaia, Pan-STARRS1, SkyMapper,2MASS, andWISE photometry for ∼ 100 million stars. We have paid special attention to the space within200 pc of the Sun and high Galactic latitudes as regions where the extinction estimates have had a largerelative uncertainty so far. Our maps estimate the extinction within the Galactic dust layer from the Sunto an extended object or through the entire dust half-layer from the Sun to extragalactic space with anaccuracy σ(AV) = 0.06 mag. This gives a high relative accuracy of extinction estimates even at highGalactic latitudes, where, according to our estimates, the median total Galactic extinction through theentire dust half-layer from the Sun to extragalactic objects is AV = 0.12 ± 0.06 mag. We have shown thatthe presented maps are among the best ones in data volume, space size, resolution, accuracy, and otherproperties.