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Social robots, owing to their embodied physical presence in human spaces and the ability to directly interact with the users and their environment, have a great potential to support children in various activities in education, healthcare and daily life. Child–Robot Interaction (CRI), as any domain involving children, inevitably faces the major challenge of designing generalized strategies to work with unique, turbulent and very diverse individuals. Addressing this challenging endeavor requires to combine the standpoint of the robot-centered perspective, i.e. what robots technically can and are best positioned to do, with that of the child-centered perspective, i.e. what children may gain from the robot and how the robot should act to best support them in reaching the goals of the interaction. This article aims to help researchers bridge the two perspectives and proposes to address the development of CRI scenarios with insights from child psychology and child development theories. To that end, we review the outcomes of the CRI studies, outline common trends and challenges, and identify two key factors from child psychology that impact child-robot interactions, especially in a long-term perspective: developmental stage and individual characteristics. For both of them we discuss prospective experiment designs which support building naturally engaging and sustainable interactions. [ABSTRACT FROM AUTHOR]

Global and regional sea level variations are important indicators of climate change and are derived from accurate sea surface height measurements and precisely determined orbits of altimetry satellites. To validate and improve the quality of these orbits, comparisons with external solutions are important. Since orbit solutions of different institutions are not necessarily provided at the same time instants, interpolation is required for comparison. In this study, we investigate the appropriate interpolation method and its degree to reduce interpolation errors to sub-millimetre levels. We also assess the magnitude of errors occurring at transformations when expressing orbit differences not only in the terrestrial reference frame (Cartesian coordinates), but also in local orbital and ellipsoidal coordinates. The analyses conducted in this study provide good results for Hermite interpolation of degrees 7–11 and Newton interpolation of at least degree 9 with a three-dimensional interpolation error of 0.6 mm and a scattering of 0.2 mm on average for satellite coordinates given with an accuracy of 1 mm in the SP3 format. These interpolation settings limit transformation errors between coordinate systems to ±0.01 mm and incorrect mapping of interpolation errors into certain components in the target system to ±0.02 mm. The spectral analysis of orbit differences is affected up to 0.1 mm in magnitude with appropriate interpolation settings. Extending the number of decimal digits of the satellite position and velocity in SP3 files by one digit benefits the orbit comparisons and reduces the interpolation error by 90% from 0.6 to 0.06 mm. The results are obtained using piece-wise interpolation and a validity interval inside the interpolation interval to minimise the effects of the Runge phenomenon. [ABSTRACT FROM AUTHOR]

The classical problem of stationary waves on the surface of an ideal incompressible homogeneous fluid of finite depth is considered. The solution approach to the problem is related to Stokes' second method, but has the following differences: due to the one-dimensional integro-differential equation with cubic nonlinearity obtained for the profile of a stationary wave on the surface of the finite-depth fluid, the original problem is reduced to a one-dimensional one. The solution is obtained up to the seventh approximation. [ABSTRACT FROM AUTHOR]

Liver diseases accompanied by obstructive cholestasis (OC) often depend on sex. Prolactin hormone levels are often elevated in a variety of hepatopancreatobiliary zone diseases, which is an adverse prognostic sign. To clarify the role of prolactin in the development of pancreatitis under OC conditions, structural changes in hepatic and pancreatic tissue female rats against the background of hyperprolactinemia were investigated. The rats were divided into the following experimental groups: group K—control animals; group HyperPrl—animals with normal hepatic function against the background of hyperprolactinemia; group BP—animals with biliary pancreatitis under OC; group BPhyperPrl—animals with biliary pancreatitis under OC against the background of hyperprolactinemia. Hyperprolactinemia was modeled by transplanting the donor's pituitary gland under the recipient's kidney capsule. Biliary pancreatitis was simulated with a ligation of the biliopancreatic duct 1 cm prior to its discharge into the duodenum, causing obstruction of the ducts of the splenic segment of pancreas. After 14 days of operations, a biomaterial was collected. The biochemical indicators of the blood serum confirmed the development of OC and pancreatitis. The structure of the pancreatic parenchyma in the BP and BPhyperPrl groups was changed, especially in the splenic segment. In both groups, tubulo-insula and tubulo-acinar complexes, inflammatory infiltration, acinaro-ductal metaplasia were found, which was accompanied by severe pancreatic parenchyma fibrosis in the group BPhyperPrl. It is important to note that the duodenal segment of pancreas continued to compensate for pancreatitis development in the BP and BPhyperPrl groups. In the hepatic tissue, histological confirmation of the development of obstructive cholestasis was shown in the BP and BPhyperPrl groups, with the loss of the beam structure of hepatocytes and the development of pericellular fibrosis against the background of hyperprolactinemia. Thus, we first showed in our work that female rats with increased prolactin concentration on the background of OC develop a heavier form of pancreatitis with a pronounced pancreatic fibrosis. This model of the development of biliary pancreatitis under OC can be used not only to study the role of prolactin in disruption of the pancreas, but also its participation in compensatory reactions to maintain the work of the exocrine part of the pancreas in this pathology. [ABSTRACT FROM AUTHOR]

Objective: The β-pore-forming toxins hemolysin II (HlyII) and cytotoxin K2 (CytK2) are important pathogenic factors of the opportunistic bacterium Bacillus cereus and are secreted as monomers that can oligomerize in the presence of a target cell to form transmembrane channels. Analysis of the nucleotide sequence of HlyII and CytK2 suggests the possibility of truncated forms of these proteins that was confirmed by immunochemical, and chromatography-mass spectroscopic analyzes. Methods: HlyII and CytK2 were expressed in recombinant strains of E. coli BL21(DE3) carrying plasmids pET29 which produced the intracellular proteins HlyII and CytK2 from B. cereus ATCC14579T. In the case of HlyII, fractions containing soluble intracellular proteins, periplasmic proteins, and cellular debris were obtained and analyzed using monoclonal antibodies. The truncated protein forms HlyII and CytK2 were analyzed by chromatography-mass spectrometry analysis. Results and Discussion: Analysis of the primary amino acid sequences of HlyII and CytK2 revealed the presence of potential internal translation initiation sites within the sequence. The presence of the truncated forms of HlyII was confirmed by immunochemical analysis using monoclonal antibodies and by chromatography-mass spectrometry. During expression of the CytK2 protein in E. coli cells, a protein fragment was identified and excised from a polyacrylamide gel, the identity of which with the CytK2 protein was confirmed by chromatography-mass spectrometry analysis. Conclusions: The results obtained confirm the general concept that the bacterial genome is capable of encoding a wider range of proteins than the number of genes it contains. The opportunistic bacterium B. cereus is often the cause of nosocomial infections, one of its key virulent factors are hemolysin II and cytotoxin K2. Using monoclonal antibodies and mass spectrometric analysis it has been shown that these hemolytic enzymes are capable of forming shortened forms. [ABSTRACT FROM AUTHOR]

Currently, the properties of molten lithium, sodium and potassium fluoride eutectic mixtures with different additions are immensely important for the development of molten salt nuclear reactors. In the present work, the density of molten FLiNaK mixtures with additions of neodymium fluoride was studied by the Archimedean method. The neodymium fluoride addition increased the density of the 46.5 mol% LiF–11.5 mol % NaF–42.0 mol % KF (FLiNaK) and FLiNaK + 25 mol% NdF3 mixture from 2.00 g⋅cm−3 to 3.25 g⋅cm−3, respectively. Thermal diffusivity was measured by the laser flash method. It was found to decrease abruptly as the NdF3 concentration increased. Thermal conductivity of the FLiNaK–NdF3 system, which was calculated using thermal diffusivity, density and heat capacity values, was lower than that of molten FLiNaK at the same temperature. The composition with 25 mol % NdF3 (0.69 W⋅m−1⋅K−1) had a lower value of thermal conductivity than molten FLiNaK without additions (0.74 W⋅m−1⋅K−1) at the same temperature of at 973 K. It can be concluded that neodymium fluoride additions resulted in the density growth and decrease in the thermal diffusivity, heat capacity and thermal conductivity of molten FLiNaK. The change in the neodymium fluoride concentration can affect the technological process in nuclear reactor. [ABSTRACT FROM AUTHOR]

This article describes an innovative technical solution developed by the authors that can be used to improve the quality, reliability, safety, and service life of hydraulic units. The problems of vibration control are discussed. Phase-chronometric diagnostics are proposed. The possibilities of significantly increasing the accuracy of hydraulic unit operation control are presented. [ABSTRACT FROM AUTHOR]

Superconducting qubits are considered as a promising platform for implementing a fault tolerant quantum computing. However, surface defects of superconductors and the substrate leading to qubit state decoherence and fluctuations in qubit parameters constitute a significant problem. The amount and type of defects depend both on the chip materials and fabrication procedure. In this work, transmons produced by two different methods of aluminum etching: wet etching in a solution of weak acids and dry etching using a chlorine-based plasma are experimentally studied. The relaxation and coherence times for dry-etched qubits are more than twice as long as those for wet-etched ones. Additionally, the analysis of time fluctuations of qubit frequencies and relaxation times, which is an effective method to identify the dominant dielectric loss mechanisms, i-ndicates a significantly lower impact of two-level systems in the dry-etched qubits compared to the wet-etched ones. [ABSTRACT FROM AUTHOR]

A theoretical model is proposed that is capable of describing the current–voltage characteristic for a bipolar filament-type memristor during reversible switching. The model makes it possible to describe various types of current–voltage curves observed in experiments. It is established that the initially formed filament, after a series of switchings, acquires a stationary shape that repeatedly reproduces the current–voltage characteristic during further switchings. [ABSTRACT FROM AUTHOR]

The thermophysical properties of molten salts promising for the nuclear industry are crucial, but the available data are limited and contradictory. The thermal diffusivity of the molten mixtures (NaF-KF)eut–UF4 containing 30, 40, and 50 mol % UF4 was measured by the laser flash method. The thermal diffusivity was found to be almost independent of temperature in the range of about 100° (1070 K–1170 K), which makes it possible to extrapolate values to low or high temperatures. The thermal conductivity of the molten mixtures (NaF-KF)eut–UF4 was calculated using the thermal diffusivity, density, and heat capacity data. Density was estimated using the molar volume of the molten binary systems NaF-UF4 and KF-UF4. The heat capacity of the ternary system NaF-KF-UF4 was evaluated based on the heat capacity of individual salts, taking into account the additivity law. The thermal conductivity of the molten mixtures 0.7(NaF-KF)eut–0.3UF4, 0.6(NaF-KF)eut–0.4UF4, and 0.5(NaF-KF)eut–0.5UF4 changes slightly with the UF4 content and temperature; for example, at 1123 K it is 0.48, 0.45, and 0.45 W·m−1·K−1, respectively. The thermal diffusivity of the pure molten UF4 was estimated using three independent approaches: the concentration, the temperature, and the volume dependences of the thermal diffusivity. The estimated value of the thermal diffusivity for the molten UF4 was about 0.12 × 10–6 ± 0.05 × 10–6 m2·s−1. [ABSTRACT FROM AUTHOR]

Some results on the miniaturization of silicon-on-insulator (SOI) structures and SOI elements of integrated circuits (IC) were presented. To increase IC performance efficiency, it was necessary to increase barriers and pulling electrical fields by means of high- dielectrics and nanoscales, which appreciably reduced the mobility of charge carriers at a decrease in the length and width of a channel. Along with an increase in leakage due to source-drain tunnel currents, this limited the physical length of a channel by 10 nm even when silicon was replaced by two-dimensional (2D) materials, such as graphene and metals dihalcogenides. Three-dimensional (3D) integration in the form of double-gate transistors with complete depletion in the SOI structures with high- buried dielectric (h- BOX) in the form of so-called fin transistors (FinFET) with two to four gates all around (GAA) and channels from nanowires (NW FET), nanosheets (NS FET), and nanoforks (FS FET), 2D materials, and their 3D packing made it possible to increase the number of transistors on a chip, but not their performance efficiency. The variant considered as an alternative to improve the functionality of these elements was to replace the dielectrics in capacitors and transistors with ferroelectrics and resistors with memristors to turn from binary to neuromorphic logic and, in addition, to implement the principles of radiophotonics and quantum devices and sensors with parallel processing. The dynamically adjustable threshold and polarization of gate ferroelectrics in the complementary MOS metal-oxide-semiconductor field-effect transistors (MOS FET) of heterosystems on a chip (SoC) will retain ultralow power consumption. [ABSTRACT FROM AUTHOR]

In this work, using biochemical and molecular genetic approaches, the genotypes of sugar beet were studied under conditions simulating salt stress to select stable samples for breeding. Sugar beet plants grown under 150-, 280-, and 500-mM salinity were used as materials for experiments. Under conditions of 150-mM salinity, RMS-127, O-type 2113, OP 021729, and MS 020026 samples showed an increase in catalase activity by 33.0, 14.1, 81.4, 5.1%, accordingly, in comparison with control samples. In these genotypes, with an increase in NaCl concentration to 280 mM, an increase in superoxide dismutase activity was noted, by 28.9% in RMS-127, 78.7% in MS 020022, 54.3% in O-type 09001, 65.5% in OP 021722, and 67.3% in OP 021729 relative to the control. As a result of quantitative real-time RT-PCR, the expression of the SOD and CAT genes was detected in the studied sugar beet genotypes under conditions of 150- and 280-mM salinity. An increase in the expression of the SOD gene was shown in samples MS 020026, O-type 2113, and OP 021729 at 150-mM salinity by 2.5 times on average relative to the control. The maximum expression level of the SOD gene was established in the MS 020022 and RMS-127 genotypes at 280-mM salinity (1.5 times higher than the control). In MS 020026, MS 020022, and O-type 09001, the maximum gene expression was recorded at 150 and 280 mM of salt by more than five times compared to the control and by three times in O-type 2113 at 150 mM compared with the control. According to the results of the study, all the studied genotypes were selected as salinization-resistant starting material for breeding. [ABSTRACT FROM AUTHOR]

The thermophysical properties of molten salts promising for the nuclear industry are crucial, but the available data are limited and contradictory. The thermal diffusivity of the molten mixtures (NaF-KF)eut–UF4 containing 30, 40, and 50 mol % UF4 was measured by the laser flash method. The thermal diffusivity was found to be almost independent of temperature in the range of about 100° (1070 K–1170 K), which makes it possible to extrapolate values to low or high temperatures. The thermal conductivity of the molten mixtures (NaF-KF)eut–UF4 was calculated using the thermal diffusivity, density, and heat capacity data. Density was estimated using the molar volume of the molten binary systems NaF-UF4 and KF-UF4. The heat capacity of the ternary system NaF-KF-UF4 was evaluated based on the heat capacity of individual salts, taking into account the additivity law. The thermal conductivity of the molten mixtures 0.7(NaF-KF)eut–0.3UF4, 0.6(NaF-KF)eut–0.4UF4, and 0.5(NaF-KF)eut–0.5UF4 changes slightly with the UF4 content and temperature; for example, at 1123 K it is 0.48, 0.45, and 0.45 W·m−1·K−1, respectively. The thermal diffusivity of the pure molten UF4 was estimated using three independent approaches: the concentration, the temperature, and the volume dependences of the thermal diffusivity. The estimated value of the thermal diffusivity for the molten UF4 was about 0.12 × 10–6 ± 0.05 × 10–6 m2·s−1. [ABSTRACT FROM AUTHOR]

The conversion of protons to positrons at the horizon of a black hole (BH) is considered. It is shown that the process may efficiently proceed for BHs with masses in the range – g. It is argued that the electric charge of BH acquired by the proton accretion to BH could create electric field near BH horizon close to the critical Schwinger one. It leads to efficient electron-positron pair production, when electrons are back captured by the BH while positrons are emitted into outer space. Annihilation of these positrons with electrons in the interstellar medium may at least partially explain the origin of the observed 511 keV line. [ABSTRACT FROM AUTHOR]

The article considers types of contact fatigue of vehicle transmission gears. It is shown that the main operability criterion for transmission gears of tractors and heavy-duty vehicles is deep contact fatigue of tooth surfaces. It is established that the procedure for calculating gear durability presented in GOST 21354–87 has significant errors, which results in significant uncertainty of the calculations. A procedure for calculating gear life expectancy that incorporates fatigue resistance of the tooth material and is based on the dependence of the limit of deep contact endurance on the hardness and structure of the hardened layer is proposed. An example of calculating gear life expectancy is considered, and the results are compared with bench test data. [ABSTRACT FROM AUTHOR]

The dependencies establishing the relationship between the tensile stresses, maximum stresses, and parameters of asymmetric out-of-flatness of strips during elastic tension for the biquadratic law of stress distribution over the width have been obtained. A comparative analysis of the obtained dependences with those known for the quadratic law of stress distribution is performed. The obtained dependencies allow the stresses and parameters of out-of-flatness to be calculated more accurately in case of partial concealment of a defect in the stretched strip and, accordingly, its treatment modes to be adjusted (for example, during drawing, hot-dip galvanizing, and continuous annealing). A more accurate calculation of the maximum stresses along the width, taking into account the asymmetry of the defect, makes it possible to reduce the probability of strip breakage and stabilize the technology of their production. The obtained dependencies can be applied in automatic flatness control systems for the production of cold-rolled strips. [ABSTRACT FROM AUTHOR]

Data are presented that indicate that when the vegetation conditions of plants change, the expression levels of genes encoding chloroplast carbonic anhydrases, as well as the carbonic anhydrase activity of chloroplast compartments, change. The results of experiments with mutants in the genes of chloroplast carbonic anhydrases indicate that the activity of chloroplast carbonic anhydrases determines the nature of changes in photosynthesis reactions in response to changes in environmental conditions. Possible mechanisms of carbonic anhydrase participation in the light-dependent processes in the chloroplast are proposed. Based on the results we obtained, a hypothesis has been proposed about the interrelated functioning of carbonic anhydrases in chloroplasts. [ABSTRACT FROM AUTHOR]

The relationship between individual phytochemical constituents and overall antioxidant capacity or total phenolic content (TPC) is poorly understood in faba bean. This study used a range of linear and nonlinear regression techniques to investigate whether the antioxidant capacity and TPC of 60 faba bean samples (flour and methanolic extracts) could be predicted from 12 individual compounds (10 common polyphenols and 2 alkaloid glycosides) measured in the same samples. Nonlinear regression using machine learning with a Radial Basis Function showed the best performance for antioxidant and TPC prediction across all sample types, while multiple linear regression allowed moderately accurate predictions in most sample matrices. Improved performance metrics were seen for the methanolic extracts compared to the flour samples. The strongest predictors of antioxidant activity in the multiple linear regression models were protocatechuic acid, p-hydroxybenzoic acid, and ferulic acid, suggesting that these compounds are particularly important contributors to the high antioxidant activity of faba bean. Understanding the relationship between individual constituents and the antioxidant capacity may help food technologists and plant breeders develop faba bean products with maximal health benefits. [ABSTRACT FROM AUTHOR]

CsqR (YihW) is a local transcription factor that controls expression of yih genes involved in degradation of sulfoquinovose in Escherichia coli. We recently showed that expression of the respective gene cassette might be regulated by lactose. Here, we explore the phylogenetic and functional traits of CsqR. Phylogenetic analysis revealed that CsqR had a conserved Met25. Western blot demonstrated that CsqR was synthesized in the bacterial cell as two protein forms, 28.5 (CsqR-l) and 26 kDa (CsqR-s), the latter corresponding to start of translation at Met25. CsqR-s was dramatically activated during growth with sulfoquinovose as a sole carbon source, and displaced CsqR-l in the stationary phase during growth on rich medium. Molecular dynamic simulations revealed two possible states of the CsqR-s structure, with the interdomain linker being represented by either a disordered loop or an ɑ-helix. This helix allowed the hinge-like motion of the N-terminal domain resulting in a switch of CsqR-s between two conformational states, "open" and "compact". We then modeled the interaction of both CsqR forms with putative effectors sulfoquinovose, sulforhamnose, sulfoquinovosyl glycerol, and lactose, and revealed that they all preferred the same pocket in CsqR-l, while in CsqR-s there were two possible options dependent on the linker structure. [ABSTRACT FROM AUTHOR]

The collision of drops of water and elastic liquids with a thin cylinder (fiber) has been studied. Aqueous solutions of polymers were used as elastic liquids, which simulated the rheological behavior of oral fluid—the main carrier of infections by airborne drops. Water as a Newtonian fluid was investigated to identify the elastic effects when comparing the collisions of Newtonian and non-Newtonian fluids—water and polymer solutions. The flight path of the drop and the cylinder axis are mutually perpendicular. Attention is focused on the difference between the collisions of water drops and drops of elastic liquids. In the experiments, the diameter of the drop was 3 mm, and the diameter of the horizontal stainless-steel cylinders was 0.4 and 0.8 mm. Drops were formed by the slow flow of liquid from a vertical stainless-steel capillary with an outer diameter of 0.8 mm, from which the drops were periodically separated under the influence of gravity. The velocity of the drop before the collision was determined by the distance between the end of the capillary and the target (cylinder); in the experiments, this distance was 5, 10, and 20 mm. The velocities of falling drops before impact were estimated in the range of 0.2–0.5 m/s. The collision process was monitored using high-speed video recording methods with frame rates of 240 and 960 Hz. Water and aqueous solutions of polyacrylamide with a molecular weight of 11 million and concentrations of 100 and 1000 ppm were used as test liquids. Experiments have shown that, depending on the height of the drop and the concentration of the polymer, various drop collision scenarios are possible: (1) short-term rebound of the drop from an obstacle, (2) braking and stopping the drop on the obstacle, (3) flow of the drop around a cylindrical obstacle while maintaining continuity and continuing free flight, (4) disintegration of the drop into two secondary drops, each with its own history of subsequent flight. [ABSTRACT FROM AUTHOR]

Molten fluoride salts are under development for use as fuel coolant and thermal storage in industrial nuclear energy production. This study focuses on the experimental and molecular dynamic investigation of thermal conductivity and ion diffusion in the eutectic molten salts of NaF–KF and NaF–KF–MgF2. Experimental and calculated data demonstrate that the temperature-dependent thermal conductivity can be accurately represented as a decaying linear function for both melts. The significant diffusion coefficient of fluorine ions in the NaF–KF molten system can be attributed to the considerable number of Coulomb repulsions among the abundant negative ions in the irregular system. The findings of this study provide insights into the behavior of NaF–KF and NaF–KF–MgF2 molten salt mixtures under operating conditions in high-temperature power plants. [ABSTRACT FROM AUTHOR]

We prove the surjectivity part of Goncharov's depth conjecture over a quadratically closed field. We also show that the depth conjecture implies that multiple polylogarithms of depth d and weight n can be expressed via a single function Li n - d + 1 , 1 , ⋯ , 1 (a 1 , a 2 , ⋯ , a d) , and we prove this latter statement for d = 2 . [ABSTRACT FROM AUTHOR]

Abstract—Experiments were carried out on the production and testing of hard alloys from VK10KhOM and VRK15 powders coated with multigraphene obtained by the electrochemical method. Samples with multigraphene were sintered under standard conditions for the VK10KhOM and VRK15 grades. The amount of multigraphene additive was 0.1 wt % for the VK10KHOM alloy and 0.1 and 0.5 wt % for the VRK15 alloy. Friction tests on VK10KhOM samples showed that the width of wear areas of samples with multigraphene is 8% smaller than the original ones. At 0.1 wt % of multigraphene, the density of samples of the VK10KhOM grade is 14.5 g/cm3 and VRK15 is 14.0 g/cm3, and the porosity is 0.02 and 2%, respectively. Comparative tests were carried out on cutting VT-3 titanium. As a result of cutting, it was found that the coating of powders with multigraphene increases the durability of carbide inserts of both grades. It was shown that, for VRK15, the plate life increased by 4 times, but for the VK10KhOM grade, it was not possible to determine the failure time of the plate. The increase in wear resistance is presumably caused by a decrease in the coefficient of friction due to multigraphene, which, when dissolved in the hard alloy, is released in the form of graphite. [ABSTRACT FROM AUTHOR]

The current situation in cosmology and particle physics, which are two closely related fields of fundamental physics, is unique. The Standard Model of particle physics excellently reproduces all existing experimental data except for neutrino oscillations. Similarly, the comparison of the standard cosmological model with astronomical observations indicates that we well understand the evolution of the Universe from its "birth" to the present. However, to understand mechanisms of numerous cosmological phenomena, it is certainly necessary to go beyond the Standard Model. These are primarily the problems of dark matter and dark energy, generation of the baryon asymmetry of the Universe, and the mechanism of inflation expansion. The problem of the appearance of cosmic magnetic fields and the recent problem of the existence of massive black holes whose number in the Universe is much larger than the expected values are among less known, but also very important problems in conventional cosmology and astrophysics. To understand and possibly solve these problems, it is very important to provide deep insight into the Universe and to obtain data on physical processes at the early stages of the cosmological evolution. Multi-messenger observations involving all possible messengers ("windows") provide a powerful tool for this. In addition to conventional detection of electromagnetic radiation in all bands and all types of cosmic rays, the observations of gravitational waves have recently opened a new window. A complex analysis of information obtained from various astronomical data has been performed in our works supported by the Russian Science Foundation (project no. 20-42-09010 "Opening of New Windows to the Early Universe by Means of Multi-Messenger Astronomy"). In particular, the characteristics of cosmic magnetic fields and possible mechanisms of their appearance have been studied and the observed manifestations of primary black holes have been examined using the data on gravitational waves observed at the LIGO/Virgo/KAGRA interferometers. [ABSTRACT FROM AUTHOR]

The mechanism of resistive switching in Pt/HfO2(8 nm)/HfOXNY(4 nm)/TiN structures, in which there are two resistive switching modes: bipolar resistive switching and complementary resistive switching. We demonstrate that resistive switching without external current compliance is possible. It is shown experimentally that the conductivity in the low-resistance state corresponds to the space-charge-limited current. A qualitative model is proposed that describes the transition from bipolar resistive switching to complementary resistive switching using Schottky barrier modulation at the metal-insulator interface. Based on this model, an explanation is given for the degradation of the low-resistance state during endurance measurements. [ABSTRACT FROM AUTHOR]

A plasma-chemical method for the modification of silicon carbide particles is presented, which makes it possible to obtain particles with a controlled surface morphology. The variable parameter of particle processing was the ratio of the fraction of plasma-forming (Ar) and additional (H) gases. It was shown that at Ar/H = 100/0, the formation of a carbon shell is observed; at Ar/H ratios of 91/9 and 84/16, the particles are characterized by a carbon shell decorated with silicon nanoparticles or nanowires, respectively. The modified particles were analyzed using scanning electron microscopy and Raman spectroscopy. [ABSTRACT FROM AUTHOR]

The electrophysical parameters of the plasma and the kinetics of plasma-chemical processes in a CF4 + H2 + Ar mixture while varying the CF4/H2 ratio are studied. When using diagnostic methods and plasma modeling together, it is found that replacing tetrafluoromethane with hydrogen (a) leads to a decrease in the plasma density and an increase in electronegativity; and (b) it causes a disproportionately sharp drop in the concentration of fluorine atoms. The reason for the latter effect is the increase in the frequency of the death of atoms in reactions of the CHFx + F → CFx + HF type initiated by heterogeneous recombination via the CFx + H → CHFx mechanism. The simultaneous increase in the concentration of polymer-forming CHxFy (x + y < 3) radicals indicates an increase in the polymerization load of the plasma on the surfaces in contact with it. [ABSTRACT FROM AUTHOR]

Consideration is continued of the problem of the inertial control law by the output synthesis of a continuous nonlinear stochastic object, which is optimal on average and on a finite time interval, and works with the desired speed. An algorithm for synthesizing the optimal structure of a dynamic controller of a selected finite order, obtained in the first part of the article for the case of accurate measurements of the control object's state variables part, is presented. Its application is demonstrated in detail for the case when the state variables of the control object are measured with random errors. Using the example of a linear-quadratic-Gaussian problem, it is shown that the proposed controller of the corresponding order also satisfies the well-known separation theorem. [ABSTRACT FROM AUTHOR]

Abstract—Molten mixtures of sodium and potassium cryolites KF–(10 wt %)NaF–AlF3 with a cryolite ratio CR = 1.5 are promising electrolytes for the production of aluminum alloys with scandium, yttrium, zirconium, and boron using aluminothermic and electrochemical reduction of alloying component oxides at temperatures of 800–850°C. The viscosity is not only an important technological parameter, but also an information source for the structure and mechanism of viscous flow of a liquid. The dynamic viscosity of the KF–(10 wt %)NaF–AlF3 (CR = 1.5) melt containing Sc2O3 (to 9.9 wt %) and Y2O3 (to 6.5 wt %) oxide additives has been measured at a constant shear rate of 12 s–1 in the temperature range from the liquidus point to 930°C. The viscosity of the KF–(10 wt %)NaF–AlF3 (CR = 1.5) melt is found to change from 1.8 to 1.3 mPa s in the temperature range 800–930°C, which is substantially lower than the viscosity of the KF–AlF3 melt (CR = 1.5), which is 1.7–2.4 MPa s, in a lower temperature range of 800–730°C. Sc2O3 and Y2O3 oxide additives substantially increase the viscosity, which is related to the formation of complex REM ions and oxifluoroaluminates in the melt during dissolution of the oxides. [ABSTRACT FROM AUTHOR]

Ruthenium thin films were deposited by plasma enhanced atomic layer deposition (PEALD) using Ru(EtCp)2 and oxygen plasma on the modified silicon surface and SiO2/Si substrates. The substrate temperature has a significant impact on film growth. The GXRD and SIMS analysis have shown that at the substrate temperature T = 375°C there is a sharp change in the mechanisms of surface reactions, which leads to a change in the film composition from RuO2 at low temperatures to a pure Ru film at higher temperatures. This was confirmed by measurements of the electrical resistivity of Ru-based films. The lowest surface roughness ~1.5 nm was obtained at a film thickness of 29 nm deposited at 375°C on a SiO2/Si-substrate. The measured resistivity of the Ru film was 18–19 μΩ cm. Issues regarding the plasma-chemical etching of ruthenium and the spin-on of a low-k dielectric onto arrays of lines are taken into account. [ABSTRACT FROM AUTHOR]

The results of a study of promising technologies for the formation of trench and planar integrated capacitors with a high specific capacitance per unit of chip surface are presented, as well as a review of the literature and achievements of leading manufacturers of integrated circuits on this topic. In particular, the results of a study of dielectrics with a high permittivity, including ternary compounds obtained by atomic layer deposition, are presented. The issues of deposition of conformal dielectric and metallic layers in high-aspect trench structures in silicon are studied in details. The results of implementation of the novel cyclic process of deep silicon ething (nitridisation-etching) is presented. The results obtained can be used to implement industrial technological routes for the formation of integrated capacitors. [ABSTRACT FROM AUTHOR]

The article develops the possibility of forming silicon oxide structures with tapered walls using dry etching methods, including a two-stage process involving the formation of a tapered photoresist mask and plasma etching of the silicon oxide. A study of the process of tapered resist etching was carried out. The influence of plasma parameters and composition on the etching process was studied, plasma diagnostics were carried out using Langmuir probe and optical emission actinometry methods, and the mechanisms of tapered resist etching were suggested. The etching process was optimized and structures with a resist thickness of 400 nm and a sidewall angle of up to 61° were obtained. A subsequent SiO2 etching process allowed the slope of the resist to be transferred. The slope of the SiO2 wall was 57°. The resulting structures with tapered SiO2 walls make it possible to produce capacitors for studying the characteristics of dielectrics, as well as the structure of microelectromechanics and microfluidics. [ABSTRACT FROM AUTHOR]

The results are presented on changes in the parameters of pseudo-MOS transistors based on silicon-on-sapphire (SOS) mesastructures upon irradiation with swift heavy ions (SHIs) of Xe (150 MeV) and Bi (670 MeV) to a fluence of cm , indicating the accumulation of mechanical stresses and charges in the intermediate ferroelectric (Fe) layers of HfO films (HO) with a thickness of 20 nm and Hf Zr O (HZO) laminated with inserts of Al O monolayers (HA, HZA) or without them. SOS heterostructures are formed by direct bonding and hydrogen transfer of a silicon film (500 nm) with HA and HZA nanolayers pre-applied by plasma-stimulated atomic layer deposition onto sapphire. Electrophysical parameters are determined from the drain current—gate voltage characteristics ( – of pseudo-MOS transistors with tungsten drain/source electrodes (100 nm) deposited by magnetron sputtering on SOS mesastructures through a lithographic mask. Comparison of the characteristics with Raman scattering analysis showed the correspondence of the mechanical compressive stresses introduced by SHI irradiation in silicon with the ratios of the Xe and Bi track volumes in the HA ferroelectric and sapphire. [ABSTRACT FROM AUTHOR]

The influence of a capillary pressure jump in a porous medium on the equilibrium between its liquid and gas phases, defined by the Peng–Robinson equation of state, was investigated. A numerical analysis of the phase diagrams of a gas–condensate mixture, constructed in gas-pressure and liquid-pressure coordinates for different capillary pressure jumps in the mixture, has been performed. The boundary of the two-phase region of such a mixture was determined as a domain of its existence in the two-phase state. The calculations were not associated with a concrete porous medium, and they were based on the condition of phase equilibrium of such a medium at different capillary pressure jumps in it. [ABSTRACT FROM AUTHOR]

We present a brief overview of the theory of high-intensity nonlinear diffracting beams. Characteristic distortions of the profiles of acoustic waves, which are observed during the wave propagation, are described. The following features are pointed out. First, the positive and negative half periods of the original harmonic signal are differently distorted. The positive-pressure phase duration is shortened and its "amplitude" is increased. On the contrary, the region of negative pressure is somewhat extended and reduced in "amplitude." Second, the profiles are shifted to the region of negative values of the "accompanying" time, i.e., the diffraction of a convex beam leads to a slight increase in its propagation velocity. In addition, the positive pressure in some range of distances may exceed the initial value. Low-frequency geometric dispersion leads to differentiation of the weak signal profile in the focal region and in the far zone, which leads to the disappearance of unipolar video pulses. A stationary wave composed of sections of a parabolic shape can be formed in the waist. The limiting values of acoustic pressure and wave intensity in the focus are estimated. Approximate mathematical methods and the models used in the calculation of the wave profiles are described. [ABSTRACT FROM AUTHOR]

Non-destructive plasma etching processes for dielectrics with ultra-low dielectric constant are relevant for forming metallization systems of integrated circuits with a design rule of less than 28 nm. The paper demonstrates the process of atomic layer etching of dielectrics with ultralow permittivity. The process is based on the adsorption of C4F8 gas in the pores of the film in the first stage of the cycle at cryogenic temperatures (up to – 120°C) and activation of the reaction by bombardment with accelerated particles in the second stage. The proposed process is promising because the gas condensed on the surface of the pores protects their walls from chemical degradation. [ABSTRACT FROM AUTHOR]

Plasma was diagnosed using Langmuir probe and optical actinometry methods, and growth rates of films or etching of surfaces of functional layers from Ar/CF4/H2 plasma were investigated in a plasma etching setup. It was found that the deposition rate varies non-monotonically with the proportion of CF4 in the plasma, and the film deposition process is replaced by the SiO2 etching process. At high CF4 proportions in the plasma, the deposition rate is determined by the concentration of fluorocarbon radicals in the plasma. Understanding the kinetics of the fluorocarbon film deposition process enables optimization of the atomic layer etching process. [ABSTRACT FROM AUTHOR]

Transient absorption in thin PdO films in the spectral range of the resonant absorption band at 2.55 eV was investigated by the femtosecond time-resolved pump-probe spectroscopy under 800 nm (1.55 eV) and 400 nm (3.1 eV) excitation. It was found that the induced changes of absorption in the central and wing regions of the 2.55 eV band have different signs, which signifies an induced change in the shape of the absorption band. The relaxation of these changes takes place in two stages: fast, with almost the same relaxation time of τ1 = 3 ps for 800 nm and 400 nm excitation, and slow τ2 = 2 ns. The peculiarities of the induced changes of absorption reflect changes in the shape and width of the long-wavelength part of the 2.55 eV band under intense excitation. Specifically, with 800 nm excitation, the width somewhat increases, whereas under 400 nm irradiation, the width more significantly decreases. The changes under 800 nm excitation may be due to inter-band transitions from deep valence band states into empty hole states at the top of the band. Under 400 nm (3.10 eV) excitation, however, there occur inter-band transitions from the valence band into energy states above those of the 2.55 eV band and with different selection rules, which determines the above-mentioned changes of the 2.55 eV band. [ABSTRACT FROM AUTHOR]

Based on field lithostratigraphic studies, microfaunistic and palynological analyses, and optically stimulated luminescence (OSL) dating of sediments exposed in the lower part of Quaternary sections along the Zimnii coast of the White Sea, it is established for the first time that they accumulated during the Boreal transgression in the beginning of the Last Interglacial under marine and coastal marine conditions and form the Upper Pleistocene Mikulinian Horizon. This is supported by the lithology; the species composition of foraminifers, ostracods, and aquatic palynomorphs; and the OSL ages in the range of 118–104 ka. The composition of benthic microfossils indicates that the beginning of the Boreal transgression along the entire Zimnii coast was characterized by a coastal marine basin with sea-ice cover and water depths of >50 m, as well as by high sedimentation rates and stratification due to inflow of melt/river waters. The coastal marine sedimentation conditions were dominant during the regression stage along the Zimnii coast. [ABSTRACT FROM AUTHOR]

The aspects of increasing the strength of heavily loaded steel parts of transmissions of energy-intensive machinery are considered. It is noted that, along with hardness, an important parameter of the hardened cemented steel layer is its effective thickness, which is a distance from the surface of the sample (part) to the zone with a hardness of 50 HRC (529 HV0.5). It is shown that unavoidable banding of metal in the area of hardness measurement and instrumental errors during hardness measurements greatly affect the accuracy of determining the effective thickness. A method for determining the effective thickness of the cemented layer is proposed, which is based on using a second-degree polynomial to interpolate the distribution of experimentally measured values of hardness (HV0.5) in an extended range of distances from the surface of the part to the HV0.5 hardness measurement point. The error of determining the effective thickness of the cemented layer is reduced by expanding the HV0.5 hardness range in the analyzed zone, and by approximating its monotonous variation in this area, followed by solving the resulting quadratic equation. The approximating polynomial provides a statistically correct description of the behavior of cemented steel hardness (HV0.5) in the analyzed area depending on the distance from the part surface to the hardness measurement point. The effectiveness of the method was confirmed by determining the effective thickness of the cemented layer of a steel sample (grade 18KhGT) after carburizing and quenching. The obtained results will be useful when optimizing the carburizing conditions of heavily loaded gear wheels of vehicle and tractor transmissions. [ABSTRACT FROM AUTHOR]

We study intrinsic charge-carrier scattering mechanisms and determine their contribution to the transport properties of the two-dimensional ferromagnet Fe3GeTe2. We use state-of-the-art first-principles calculations combined with the model approaches to elucidate the role of the electron-phonon and electron-magnon interactions in the electronic transport. Our findings show that the charge carrier scattering in Fe3GeTe2 is dominated by the electron-phonon interaction, while the role of magnetic excitations is marginal. At the same time, the magnetic ordering is shown to effect essentially on the electron-phonon coupling and its temperature dependence. This leads to a sublinear temperature dependence of the electrical resistivity near the Curie temperature, which is in line with experimental observations. The room temperature resistivity is estimated to be ~ 35 μΩ ⋅ cm which may be considered as a lower intrinsic limit for monolayer Fe3GeTe2. [ABSTRACT FROM AUTHOR]

The depth distribution of carbon impurities in hafnium oxide films obtained by plasma-assisted atomic layer deposition is studied experimentally and theoretically. An analytical model is proposed that describes the dependence of the carbon impurity concentration profile in the film. The model takes into account the fact that the formation of a carbon impurity in the growing film may be caused by the incomplete oxidation of the organometallic precursor. The diffusion redistribution of impurities is determined by mechanisms that take into account the presence of carbon in different kinds of states: an insoluble state (carbides, carbonates), a highly mobile state (CO, CO2), and an unstable state whose lifetime is longer than the film's growth time. The possibility of controlling the carbon impurity both in deep and near-surface layers is shown. The predictions of the model are confirmed experimentally using the mass spectrometry of the secondary ions in the films obtained by atomic layer deposition. To test the theory, special structures of hafnium oxide are developed, consisting of several layers, in which the time of the plasma exposure to the sample is varied at the same dosage of the organometallic precursor. The layer with the shortest exposure time to the plasma is deposited on the substrate, then the same number of cycles on the next layer take place, provided that the exposure time is increased by a factor of n. This makes it possible to deepen the transition zones and thus protect them from the effects of the atmosphere. [ABSTRACT FROM AUTHOR]

In this work, photoluminescence from CaF2/Si multilayer structures formed on the surface of Si(111), Si(100), and SiO2/Si(100) substrates at room temperature with subsequent annealing is demonstrated. The influence of the substrate structure on the photoluminescence spectra is discussed. Studies of the photoluminescence spectra of CaF2/Si multilayer structures show that the shape and position of maxima depend on the type of substrate despite the fact that the multilayer structures themselves (the thickness of the layers and their number) are identical. The photoluminescence spectra of the samples on single-crystal Si(100) and Si(111) substrates are similar in shape and have close values of wavelengths corresponding to the maxima of the photoluminescence spectra. The positions of the maxima of the photoluminescence spectra of these samples correspond to calculations obtained on the basis of the quantum-confinement effect. At the same time, the shapes of the photoluminescence spectra of a multilayer structure on the substrate of an amorphous silicon-oxide layer differ sharply from the spectra of samples on single-crystal substrates. The photoluminescence spectra of samples on amorphous SiO2/Si(100) substrates have two maxima. It is suggested that the mechanisms of the nucleation of silicon nanocrystals and their subsequent crystallization upon annealing on amorphous SiO2/Si(100) substrates radically differ from the conditions of formation of silicon nanocrystals on single-crystal substrates. The difference in the crystal structures of the surfaces of three types of substrates creates different conditions for recrystallization during annealing and, therefore, leads to different properties of both the interfaces of these heterostructures and the nanocrystalline structures of the silicon layers. Based on the obtained experimental data, conclusion is made about the influence of the crystallographic structure of the substrates on the photoluminescence spectra. [ABSTRACT FROM AUTHOR]

The well-known problem of synthesizing the optimal on the average and on given time interval of the inertial control law for a continuous stochastic object if only a part of its state variables are accurately measured is considered. Due to the practical unrealizability of its classical infinite-dimensional Stratonovich-Mortensen solution, it is proposed to limit ourselves to optimizing the structure of a finite-dimensional dynamic controller, whose order is chosen by the user. This finiteness allows using a truncated version of the a posteriori probability density that satisfies a deterministic partial differential integrodifferential equation. Using the Krotov extension principle, sufficient optimality conditions for the structural functions of the controller and the Lagrange–Pontryagin equation for finding their extremals are obtained. It is shown that in particular cases of the absence of measurements, complete measurements and taking into account only the values of incomplete measurements, the proposed controller turns out to be static (inertialess), and the relations for its synthesis coincide with the known ones. For a dynamic controller, algorithms for finding each of its structural functions are given. [ABSTRACT FROM AUTHOR]

The electrolytic production of Al–Y and Al–Sc alloys in an electrolyte based on the KF–NaF (10 wt %)–AlF3 potassium cryolite with a cryolite ratio (CR) of 1.5 containing Al2O3, Sc2O3, or Y2O3 oxides in a cell with vertical electrodes is studied. An Fe–Ni–Cu alloy serves as an inert anode. The wettable cathode is a graphite plate coated with aluminum diboride. Electrolysis is carried out at 830°C and a cathode current density of 0.2 A/cm2. The weight of an Al2O3 additive is calculated at a current efficiency of 60%. A Sc2O3 additive is introduced into a melt in an amount of 1 wt %. The weight of an Y2O3 additive is chosen on the basis of its solubility in the melt under study. For this purpose, the influence of Y2O3 additives on the liquidus temperature of a quasi-binary mixture [KF–NaF (10 wt %)–AlF3 (CR = 1.5)]–Y2O3 is determined. Unlike Sc2O3 additives decreasing the liquidus temperature of the cryolite melt, small Y2O3 additives lead to a sharp increase in the liquidus temperature. The efficiency of the electrolytic reduction of Y2O3 is an order of magnitude higher than that of aluminothermic reduction. Under other equivalent conditions, the efficiency of the electrolytic reduction of Y2O3 is higher than that of Sc2O3. Al–Y and Al–Sc alloys with a 0.6 wt % REM are formed. However, the time to reach the maximum reduction of yttrium significantly exceeds the time to reduce scandium. Metallographic studies of the prepared alloys indicate the presence of the Al3Sc and Al2Y intermetallic compounds. A conclusion is made about a principal possibility of the low-temperature electrolytic production of Al–REM alloys in cryolite melts based on potassium cryolite in vertical cells with an inert metallic anode and a wettable cathode. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) modeling of the adsorption of atomic oxygen and hydrogen on the surface of palladium nanoparticles on graphite substrates with various defects is used to calculate the binding energies of adatoms and changes in the density of states of metal atoms upon interaction with adatoms. It is established that the adsorption of oxygen and hydrogen does not have more energetically favorable or stable adsorption sites on the surface of the nanoparticle, such as the interface with the substrate or the top, which is consistent with the results of the scanning tunneling microscopy and spectroscopy (STM/STS) experiments. [ABSTRACT FROM AUTHOR]

Basalt fiber (BF)/nickel and BF/graphite composites having various filler concentrations were prepared using mechanical alloying followed by simple press and sintering. Microwave absorption (MWA) properties of the basalt-based composites in the frequency range of 1.5–2.1 GHz were investigated. It is shown that the absorption of microwave radiation significantly depends on the properties of both the fillers (non-magnetic graphite or magnetic nickel) and their concentrations. An anisotropy of MWA in two mutually perpendicular directions in the specimen plane for both studied composites was first found. The characters of the dependences of microwave loss (MWL) on the filler concentration were shown to be similar for the BF/graphite composites and one of the orientation directions of BF/nickel composites. For these cases, the maxima of MWL for both the composites were observed at the filler concentration of 30 wt%. Further increase in the filler concentration leads to a decrease in MWL. For the case of another orientation (rotating the specimen by 90°) BF/nickel composite with the filler concentration of more than 30 wt%, the magnitude of MWL continues growing at a slow pace with nickel content. The maximum MWA in BF/graphite composites is found to be 1.5–2 times higher than for BF/nickel composites. At the same time, at low filler concentrations (less than 30 wt%), the MWA in BF/nickel composites is significantly larger than for corresponding BF/graphite composites. The structure and phase composition of the prepared composites were studied using microscopy and XRD methods. Physical mechanisms of the observed MWA peculiarities are discussed. [ABSTRACT FROM AUTHOR]

The interaction of Sc2Ni7 and Zr2Ni7 compounds (with C2/m and P63/mmc crystal structures and congruent melting temperatures of 1270 and 1438°C) in the ternary Ni–Sc–Zr system was studied employing physicochemical analysis methods (metallography, X-ray diffraction, differential thermal analysis, and electron microprobe analysis). The section between the compounds was shown to be quasibinary of peritectic type, with peritectic points of 1340 ± 13°C and 14 at.% Sc. At the peritectic temperature, about 10 at.% Zr dissolves in the Sc2Ni7-based phase and about 8 at.% Sc in the Zr2Ni7-based phase. Electrochemical studies conducted through cathodic polarization of the ternary Sc2Ni7 and Zr2Ni7 alloys using a PI-50-1 potentiostat, with a three-electrode electrochemical cell consisting of a working ceramic anode, a platinum cathode, an electrolyte (a 3% NaCl aqueous solution), and a silver chloride Ag/AgCl/KCl reference electrode, did not reveal any tendency to hydrogenation in their solid solutions. The influence of preliminary cathodic reduction of the 77.8 at.% Ni–8 at.% Sc–Zr sample on its subsequent anodic dissolution was determined. The initial surface of the 77.8 at.% Ni–8 at.% Sc–Zr sample was found to be much more resistant to anodic oxidation than the surface preliminary subjected to cathodic reduction because of a significant decrease in its oxide component. [ABSTRACT FROM AUTHOR]

The interaction of a short pulse with three types of wave profiles in a nonlinear dissipative medium are described: a stationary shock front of finite width, a nonstationary forming front, and a "stationary" wave the profile of which contains a singularity. Exact solutions to the Burgers equation are used, which describe these interactions, as well as the symmetry properties of this equation. [ABSTRACT FROM AUTHOR]