bluuebunny/crossref_metadata_2025 huggingface dataset:
Fatores de Risco ao Patrimônio Cultural do Estado de Mato Grosso
Authors: Mascaro Luciana Pelaes , Almeida Carla Cristina Rosa de , Durante Luciane Cleonice
Published: November 2024

The objective of this article is to identify the risk factors that most affect the intangible, archaeological and architectural-landscape heritage of Mato Grosso, from the perspective of managers of public institutions linked to its preservation and conservation. The research started from a survey (questionnaire) of participants' opinions regarding risk factors that affect cultural heritage, with subsequent quantification and qualitative analysis (data tabulation) and quantitative analysis (assessment of reliability and internal consistency using a statistical instrument). The most common risks for architectural-landscape heritage are Abandonment (72%, Social dimension), Mismanagement (67%) and Successive reforms and renovations (67%), both in the Governance dimension; in the Environmental dimension they are Fires (44%) and Construction of various projects (44%). For archaeological heritage, the most common risk factors in the Environmental dimension are Construction of hydroelectric plants, dams and similar (50%), Intensive crops in sensitive areas (50%), Livestock in sensitive areas (50%) and Deforestation (50%). The most common risk factors for intangible heritage are: in the Governance dimension - Mismanagement (44%) and, in the Environmental dimension: Livestock in sensitive areas (50%), Deforestation (56%) and Fires (50%). Cronbach's Alpha values ​​were 0.965 for intangible heritage, 0.962 for archaeological heritage and 0.97 for architectural-landscape heritage, concluding that the results obtained are reliable.
Stabilization of food emulsion by polysaccharides and protein-polysaccharide complexes: a short review
Authors: Lavlinskaya Maria S. , Sorokin Andrey V. , Holyavka Marina G. , Zuev Yuriy F. , Artyukhov Valery G.
Published: November 2024

Emulsions are heterogeneous systems consisting of two immiscible liquids, widely used in the food industry as the basis for some products (mayonnaise, sauces, etc.) and components for the production of functional food products containing systems for targeted delivery of biologically active substances (vitamins, nutraceuticals, flavonoids, etc.). From a thermodynamic point of view, emulsions are unstable systems with excessive surface energy; therefore, they are characterized by rapid destruction through phase separation. For the solution to this problem, emulsifiers are used, amphiphilic molecules of various natures that reduce surface tension, i.e., possess surface activity. However, most of these stabilizers are synthetic and toxic products, which significantly limits their use in the food industry. Natural biopolymers, such as polysaccharides and proteins, as well as their complexes, are amphiphilic macromolecules that combine both polar and hydrophobic fragments, have surface-active properties, low toxicity and excellent biocompatibility, thus they can be considered as promising stabilizers for food emulsions. A special place among polysaccharides is occupied by chitosans and alginates, which, in addition to other advantages mentioned above, are accessible and cheap materials.
The purpose of this work was a brief overview of the prospects for using chitosan, sodium alginate and protein-polysaccharide complexes as stabilizers for emulsions and foams for food application. The article discusses the possibility of using chitosan, sodium alginate, propylene glycol alginate, as well as various protein-polysaccharide complexes as stabilizers for heterogeneous food systems, foams and emulsions, which are the basis of many food products. In addition, special attention is paid to the prospects for the introduction of polysaccharide-based emulsifiers into industrial production and the problems that must be solved for the successful development of emulsions stabilized by biopolymers, which are the basis for thecreation of food products, are discussed
X-ray luminescence of Sr0.925–xBaxEu0.075F2.075 nanopowders
Authors: Ermakova Yulia A. , Fedorov Pavel P. , Voronov Valery V. , Batygov Sergey Kh. , Kuznetsov Sergey V.
Published: November 2024

We synthesized powders of single-phase solid solutions Sr0.925–xBaxEu0.075F2.075 (x = 0.00, 0.20, 0.25, 0.30, 0.35 and 0.40) by a precipitation technique from nitrate aqueous solutions. The lattice parameters increase linearly as the barium content increases. We recorded a significant increase in the X-ray luminescence intensity of europium at increasing barium content. Upon increasing barium content, the intensity of the luminescence of strong 5D0 → 7F1 band increases exponentially, and we observed blue and red shifts in the position of the europium luminescence bands for 5D0 → 7F1 and 5D0 → 7F4, respectively
Coupling of anode reactions in the process of electrooxidation of glycine anion on gold
Authors: Zartsyn Ilya D. , Vvedenskii Alexander V. , Bobrinskaya Elena V. , Kozaderov Oleg A.
Published: November 2024

Electrochemical processes involving organic substances are complex multi-stage reactions. In our opinion, it is incorrect to describe their kinetics using the principle of independent partial processes (or their individual stages) since electrode reactions can be coupled due to competition for active surface sites, due to common intermediate stages, or through an electron. In this case, the theory of coupled reactions or the graph-kinetic method should be used to provide the kinetic description of the process. In general, graph theory makes it possible to identify the relationship between the “structure” and the kinetic behavior of complex systems by means of graphical analysis. In the case of electrochemical reactions, structural elements are substances adsorbed on the metal surface and (or) a set of substances interacting in the reactions. The relationship between their concentrations can be characterized quantitatively by a transformation law, for example,the law of effective masses. Thus, a graph is a set of reacting substances and a sequence of reactions represented graphically. Graphs allow setting a system of kinetic equations and analyzing them by associating a certain behavior of the system with the structure of the corresponding graph. Under the assumption that one intermediate particle is involved in each elementary stage, the kinetic expressions will be linear, which corresponds to the first-order reaction model.
Graph-kinetic analysis of the processes within the Au|Gly–,OH–,H2O system confirmed that the partial multi-stage reactions of anode oxidation of glycine and hydroxyl anions are kinetically coupled. We obtained expressions for partial currents of electrooxidation of hydroxide ions and glycine anions during the anodic process occurring on gold in an alkaline glycinecontaining solution. It was shown that with an increase in the anode potential, the nature of the limiting stage of the anodicprocess changes.
Formal constants of rates and equilibria of electrochemical reactions involving particles of background electrolyte and glycinate ion were calculated. It was found that the rates of partial oxidation reactions of adsorbed OH particles and O H are significantly higher than those of organic anions (Gly- and HCOO–). This indicates that the kinetics of the electrooxidation processes of Glyis in the Au|Gly-,OH–,H2O system are determined by the kinetic features of the electrooxidation reactions of hydroxide ions
Structural, optical, and photocatalytic properties of dispersions of CuS doped with Mn2+ and Ni2+
Authors: Maskaeva Larisa N. , Lysanova Maria A. , Lipina Olga A. , Voronin Vladimir I. , Kravtsov Evgeny A. , Pozdin Andrei V. , Markov Vyacheslav F.
Published: November 2024

By calculating the ionic equilibria in the system CuCl2 (Mn2+, Ni2+) − NaCH3COO – N2H4CS, we determined the concentration regions of the formation of copper sulfide (CuS), both undoped and doped with transition metals (Mn, Ni). Using chemical deposition on frosted glass substrates, we obtained powders and thin films of CuS(Mn) and CuS(Ni) doped with manganese or nickel with a thickness of 170–200 nm. The X-ray diffraction demonstrated that CuS based dispersions have the hexagonal covelline structure (space group Р63mmc). The band gap Eg of CuS films (2.08 eV) grows to 2.37 and 2.49 eV after doping with nickel and manganese, respectively. The study demonstrated that CuS(Ni) powders have optimal photocatalytic properties in the visible spectral region. The degree of photodegradation of a methylene blue organic dye increases inalkaline environments
Synthesis and characterization of lead and cadmium hexaborates doped with Cr3+
Authors: Khamaganova Tatyana N.
Published: November 2024

Borates doped with transition metals (Mn, Cu, Cr) exhibit a significant and long-lasting luminescence at room temperature, high power, and other outstanding characteristics. Therefore, the purpose of the study was to establish the possibility of the formation of borate materials containing chromium and the determination of their structure and thermal properties.
New phases of variable composition were synthesized in the PbCd2–xB6O12:xCr3+ system by heterovalent substitution of Cd2+ions with Cr3+ ions using solid-phase reactions at 640 °C. The phases were isolated in the concentration range 0 ≤ x ≤ 7.0 mol % and characterized by X-ray phase analysis (XRD), differential scanning calorimetry (DSC) and IR spectroscopy. According to XRD and IR spectra, the resulting borates crystallize in a monoclinic cell and are assigned to one structural type (space group P21/n, Z = 4).
The crystallographic characteristics of the new phases have been determined. The crystal lattice parameters and their volumes decrease monotonically, indicating the formation of a continuous series of substitutional solid solutions in the studied concentration range. According to the DSC results, the sample PbCd2–xB6O12: 0.03 Cr3+melts incongruently at 729 °C
The synergy of transformation of isomorphous phyllosilicate structures
Authors: Chetverikova Anna G. , Makarov Valery N. , Kanygina Olga N. , Seregin Mikhail M. , Yudin Alexander A.
Published: November 2024

The article presents an analysis of the synergy of structural transformations of phyllosilicates subjected to high temperatures and microwave radiation in terms of the destruction and formation of crystal structures. Studying the synergy of transformations of crystal structures is essential for the development of new materials and technologies, because it helps to create materials with unique properties, which cannot be obtained when using the same factors separately.
The material used in the study was a polymineral complex, which contained quartz, montmorillonite, kaolinite, chlorite, paragonite, and iron oxides (listed from the largest to the smallest mass fraction). The methods used in the study allowed us to assess the structural transformations. Averaged structural formulas of the studied phyllosilicates were calculated using the oxygen method combined with a recalculation method based on the results of a microprobe analysis. Differential thermal analysis demonstrated a synergistic effect of high temperature and microwave fields registered as a decrease inthe temperature gradient of the ceramics and initiation of the sintering process at lower temperatures and with greater intensity. All the treated samples contained the amorphous phase in significant concentrations: from 15 to 25 vol. %. Half of the three-layer phyllosilicates (chlorite and montmorillonite) were destroyed by the microwave field. Kaolinite and paragonite practically did not react to external factors. The synergistic effect was the most obvious in the structural transformations of silicon and iron oxides.
Our experiments demonstrated for the first time the mechanism of formation of magnetite and hematite crystals from X-ray amorphous iron-containing films covering the particles of clay minerals. The use of the MW field and the resulting dehydration led to the formation of crystals of nuclei of iron oxides. The following high-temperature processes activated an increase in aggregated iron (magnetite and hematite). The X-ray diffraction analysis determined the presence of a synergistic effect in the evolution of structures, which could not be identified by means of IR-spectroscopy. The EPR spectroscopy allowed us to register the states of rare irregular cells with foreign paramagnetic atoms. The shift of the foreign Fe3+ from the geometric centers of octahedral crystal cells towards the minima of potential energy caused by the Jahn-Teller effect decreased the potential energy of the crystal lattice. At the same time, some chemical bonds forming the crystal cellbecame stronger, while others weakened
Structure and electrical transport properties of cation-deficient derivatives of layered neodymium–barium ferrocuprocobaltite
Authors: Chizhova Ekaterina A. , Marozau Maksim V. , Shevchenko Svetlana V. , Klyndyuk Andrei I. , Zhuravleva Yana Yu. , Kononovich Vladimir M.
Published: November 2024

Layered double perovskites (LDP) based on rare earth elements, barium, and 3d-metals with high electrical conductivity and electrocatalytic activity in the oxygen reduction reaction are promising cathode materials  for medium-temperature solid oxide fuel cells based on proton- or oxygen-conducting solid electrolytes. For the improvement of the functional characteristics of LDP, various strategies are used: a) creating composites based on LDP, b) the partial substitution of cations, and c) the creation of a deficiency of cations in various positions in the LDP structure. The advantage of the latter strategy is that it does not require complicating the chemical and, as a rule, phase composition of the LDP. The purpose of this study was the investigation of the effect of neodymium and barium deficiency on the structural and electrical transport characteristics of NdBaFeCo0.5Cu0.5O6–d LDP.
The samples were obtained by the ceramic method and characterized using X-ray phase analysis, IR absorption spectroscopy, iodometry, electron microscopy, thermal analysis, as well as electrical conductivity and thermo-EMF measurements methods.
Creation of up to 10 mol. % of vacancies in neodymium or barium sublattices had little effect on the values of the oxygen nonstoichiometry index (d) and unit cell parameters of NdBaFeCo0.5Cu0.5O6–d derivatives.  owever, it led to an increase in the crystallite size (determined by the Scherrer, Williamson–Hall and size–strain methods) and the thermal stability of these phases. The values of electrical conductivity and the Seebeck coefficient of ceramics, in general, increased, and the activation energies of the electrical transfer process decreased when a deficiency of neodymium or barium was created in its structure. In the temperature range 300–700 K, the weighted mobility of charge carriers (“holes”) varied within 0.04–0.8cm2/(V·s) and increased with increasing temperature, which is typical for the polaron conduction mechanism, and their concentration varied in the range (0.1–3)·1020 cm–3, increased exponentially with increasing temperature and, in general, when a deficiency of neodymium or barium in the NdBaFeCo0.5Cu0.5O6–d structure was created
Theoretical exploration of halogenated anthracene derivatives: unraveling electronic and molecular insights
Authors: Othman Khdir Ahmed , Azeez Yousif Hussein , Omer Rebaz Anwar , Kareem Rebaz Obaid
Published: November 2024

This research article delves into the profound ramifications of halogenation on anthracene within the captivating domain of polycyclic aromatic hydrocarbons (PAHs). By employing Density Functional Theory (DFT) calculations, the study comprehensively explores the intricate interplay between halogen atoms and the molecular framework of anthracene. The entwining of halogens such as fluorine, chlorine, and bromine with aromatic rings orchestrates a symphony of changes, reshaping electronic structures, reactivity, and optical behaviors. This investigation traverses diverse analytical landscapes, encompassing molecular orbitals and Density of States analysis, UV-visibility spectra, infrared spectroscopy, nuclear magnetic resonance (NMR), and natural bond orbital (NBO) analysis, unveiling the intricate tapestry of molecular modifications. The electronic transitions, vibrational signatures, and NMR shifts of halogenated derivatives illuminate thedynamic effects of halogenation. Moreover, the study contemplates their potential across medicinal, environmental, and optoelectronic landscapes. Ultimately, this exploration presents a comprehensive narrative that harmonizes theoretical insights with practical applications
Photoelectrochemical activity of oxide films on silver-palladium alloys in an alkaline solution
Authors: Belyanskaya Irina A. , Bocharnikova Maria Y. , Murtazin Maksim M. , Grushevskaya Svetlana N. , Kozaderov Oleg A. , Vvedenskii Alexander V.
Published: November 2024

The continuously increasing energy needs of humanity are causing a number of serious environmental problems. One of the methods for the solution of such problems is the photocatalytic or photoelectrochemical production of a fairly environmentally friendly fuel - hydrogen gas. The studies in this field are mainly associated with the search for semiconductor material that is most suitable for photocatalysis. Oxides of some metals, including silver, can be used as such a material. The photocatalytic orphotoelectrochemical activity of the oxide is determined by the features of its electronic structure and can increase significantly when combined with another oxide. Therefore, anodic oxidation of binary alloys is considered as an accessible and, most importantly, controlled method for combining oxides of various metals. The aim of this study was to reveal the role of alloying of silver with palladium in the photoelectrochemical activity of oxide films anodicly formed in deaerated 0.1 M KOH.
The anodic formation of oxide films was carried out by the potentiodynamic method in an alkaline medium on silver and its alloys with palladium, the concentration of which ranged from 5 to 30 at. %. Photoelectrochemical activity was assessed by the magnitude of the photocurrent generated in the oxide film directly during its formation and subsequent reduction. The photocurrent was measured in a pulsed lighting mode of the electrode surface with a quasimonochromatic LED with a wavelength of 470 nm.
A positive photocurrent was recorded on all studied samples, which indicates the predominance of donor structural defects in the forming oxide film. With an increase in the concentration of palladium in the alloy, the range of potentials of photoelectrochemical activity of formed anodicly oxide films expanded. The maximum photocurrent achieved during the anodic potentiodynamic formation of the oxide film was higher, the lower the palladium concentration was. During the cathodic potentiodynamic reduction of the formed oxide films, it was possible to record even higher values of photocurrents than during their anodic formation. The highest photoelectrochemical activity, characterized by a photocurrent density of 2.89 μA/cm2 and incidental proton-to-electron conversion efficiency of 7.6%, was observed in the oxide film anodicallyformed on silver by the time the potential reached 0.6 V. Comparable values of the photocurrent and quantum efficiency (2.12 μA/cm2 and 5.6%) were recorded in the oxide film on the alloy with a palladium concentration of 10 at. % during its potentiodynamic reduction
Electrophysical properties of PIN photodiodes of the 2.2-2.6 μm range based on InGa(Al)As/InP heterostructures with a metamorphic buffer layer
Authors: Vasilkova Elena I. , Pirogov Evgeny V. , Shubina Kseniya Yu. , Voropaev Kirill O. , Vasil’ev Аndrey А. , Karachinsky Leonid Ya. , Novikov Innokenty I. , Barantsev Oleg V. , Sobolev Maxim S.
Published: November 2024

Due to a large number of applications in the near and short-wave IR spectrum and a relatively high detectivity, PIN photodiodes based on epitaxial InGa(Al)As/InP heterostructures are of a great scientific interest. The operational spectral range of such photodetectors is up to 2.6 μm. However, to reach such wavelengths it is necessary to synthesize heterostructures with metamorphic buffer layers. In our study, we investigated the current-voltage and capacitance–voltage characteristics of PIN photodiodes based on InGa(Al)As/InP heterostructures with an original metamorphic buffer layer and an In0.83Ga0.17Asabsorbing layer grown by means of molecular beam epitaxy.
The photodiode chips were formed using standard post-growth processing techniques. The diameter of the photosensitive area of the obtained diodes was 140 μm. The dark currents and the shunt resistance were ~ 300 nA and ~ 25 kΩ at the voltage of -10 mV respectively.
Therefore, the suggested metamorphic buffer layer effectively eliminates threading dislocations in the active area of the heterostructure. The obtained heterostructures with metamorphic buffer layers can be used to produce IR photodetectors for the spectral range of 2.2-2.6 μm
Influence of the nature of the organic acid salt on the currentvoltage characteristics and electrochemical impedance spectra of anion-exchange membranes
Authors: Karpenko Tatyana V. , Shramenko Vladislava V. , Sheldeshov Nikolay Viktorovich
Published: November 2024

To improve the processes of obtaining and isolating organic acids from solutions, it is necessary to understand the processes occurring on heterogeneous and homogeneous anion-exchange membranes in contact with solutions of salts of organic acids when electric current flows through the membrane system.
The purpose of this paper was to study the effect of sodium salts of acetic, malonic, and citric acids on the current-voltage characteristics (CVC) and electrochemical impedance (ECI) spectra of heterogeneous and homogeneous anion-exchangemembranes.
Heterogeneous Ralex AMH (Mega, Czech Republic) and homogeneous Lancytom® AHT (LANRAN, China) membranes in contact with 0.1 mol-eq/L solutions of neutral and acidic sodium salts of acetic, malonic and citric acids were studied. In solutions of neutral salts, the current-voltage characteristics of both membranes have a traditional form typical for mineral salt solutions, with the exception of the homogeneous Lancytom® AHT membrane in a sodium malonate solution. In thelatter case and in solutions of acidic salts of these acids CVC of both membranes are nonlinear at currents less than the limiting. This is caused by proton transfer reactions between water molecules and carboxyl groups of acid anions or acid molecules and, as a result, the rate constant of dissociation of water molecules in solutions of organic acidic salts increased by many orders of magnitude. By the appearance of additional semicircles in the spectra, ECI frequency spectra allowidentifying the occurrence of new processes in the membrane system when an electric current flows through it.
In most cases, the results of impedance measurements of the studied systems are consistent with the results of voltammetry, although the protonation-deprotonation processes in solution with the participation of organic acid anions are not reflected in the frequency spectra of a heterogeneous membrane. This feature may have been caused by a greater intensity of electroconvection near the surface of heterogeneous anion-exchange membranes as compared to homogeneous anionexchange membranes
Mechanical properties and catalytic activity of the Cu-36Pd (at. %) alloy foil surface after cleaning
Authors: Morozova Natalia B. , Dontsov Alexey I. , Khmelevskaya Tatyana N.
Published: November 2024

The purpose of the study was to evaluate the effect of mechanical treatment and ion sputtering on hydrogen sorption and the mechanical properties of the surface of the membrane foil of the Pd-Cu solid solution system obtained by rolling.
The efficiency of mechanical and ion beam treatment in cleaning of the surface of membrane foil of the Pd-Cu solid solution system obtained by rolling was assessed using cyclic voltammetry, Auger electron spectroscopy and atomic force microscopy.
It was established that ion beam treatment (Ar+) and mechanical treatment reproduce the elemental composition of the surface, corresponding to the original composition of the solid solution, and forms a developed relief. The change in the asymmetry of the relief roughness after ion-beam treatment indicates the formation of microcracks on the foil surface, which reduce hardness and plasticity. Ion-beam surface treatment also contributes to the cleaning of the surface from rolling artefacts, which leads to a twofold increase in the ionization rate of atomic hydrogen, compared to a sample subjected to mechanical treatment
Photoluminescence of GaPNAs/GaP(N) superlattices and bulk GaPN layers on GaP substrates
Authors: Nikitina Ekaterina V. , Sobolev Maxim S. , Pirogov Evgeny V. , Makhov Ivan S. , Nadtochiy Alexey M. , Vasilkova Elena I. , Kryzhanovskaya Natalia V.
Published: November 2024

The addition of a few percent of nitrogen to GaP or GaPAs allows obtaining GaPNAs solid solutions that are lattice-matched to the silicon substrate over a wide range of band gaps, which makes it possible to obtain optoelectronic silicon integrated circuits. However, materials with a small fraction of nitrogen are understudied due to the difficulty in epitaxial growth of quaternary solid solutions with three materials of group V. The purpose of the study was the investigation of the influence of the substrate temperature during the epitaxial growth of dilute nitride materials (GaPN solid solution and GaPNAs/GaP(N) superlattices) on their optical properties, as well as the influence of the growth temperature and superlattice design on the bandgap of the resulting material.
It was shown that there is an optimal growth temperature for samples: at temperatures below the optimal, non-radiative recombination at defects predominates, and at a temperature higher than the optimal one, the solid solution of the GaPN layer material decomposes into components with a larger and smaller fraction of nitrogen. Studies were also carried out on the decay of photoluminescence intensity over time in the studied structures at room temperature, which allowed us to evaluate the influence of growth parameters and structure design on the lifetime of nonequilibrium charge carriers. The best lifetime for structures with superlattices was obtained for the GaPNAs/GaPN superlattice and amounted to ~0.2 ns.
As a result, the optimal growth temperatures were determined for bulk GaPN layers and for GaPNAs/GaP(N) superlattices, which leads to an increase in the PL intensity and lifetime of the carrier
A molecular dynamics simulation of the release of desloratadine from alloys containing polyvinylpyrrolidone
Authors: Polkovnikova Yulia A. , Belal Mohamed , Slivkin Alexey I.
Published: November 2024

Computer modeling is currently a promising technique used in pharmaceutical technologies to develop drug compositions. Molecular dynamics has provided space and time resolutions unavailable during experiments and thus has greatly extended the capabilities of chemistry and some other areas. Molecular dynamics stimulations are very important for the development of solid drug dispersions. The purpose of this study is to simulate the molecular dynamics of the release of desloratadine from alloys containing polyvinylpyrrolidone-10000 into the dissolution medium.
The release of desloratadine from alloys containing polyvinylpyrrolidone-10000 was simulated by the method of molecular dynamics (Gromacs 2023 program, Amber 99 force field). The study involved calculating van der Waals energies of interaction between desloratadine and PVP and desloratadine and water and the proportion of desloratadine molecules that lost their bonds with PVP. The desloratadine molecule was considered released into water provided that it did not bind either to the polymer or water.
It was found that the degree of desloratadine release from PVP into the aqueous medium was the highest at a ratio of 1:1 (24.56±2.08%), and the lowest at ratios of 1:2 and 1:5 (8.27±1.79 and 8.65±0.98%, respectively). At a ratio of 1:1, the average energy of interaction between desloratadine with PVP per one molecule of desloratadine was the highest (–36.13±0.62 kJ/mol) when the energy of interaction between desloratadine and water was low (–52.03±0.82 kJ/mol), which indicates that desloratadine involvement in the solvation and desorption processes was the highest at this ratio. The average energy of interaction between desloratadine and the polymer was the lowest at a ratio of 1:5 (–52.03±0.82 kJ/mol) when the energy of interaction between desloratadine and water was –44.45±1.60 kJ/mol. This fact indicates a low intensity of the  esorptionand solvation processes at this ratio
Residual strain evaluation in GaN/AlN multiperiod superlattices grown on SiC/Si
Authors: Seredin Pavel V. , Sharofidinov Shukrilo Sh. , Goloshchapov Dmitry L. , Buylov Nikita S. , Eremeev Konstantin A. , Yusupova Shaira A. , Kukushkin Sergey A.
Published: November 2024

In our study, we formed a multilayer heterostructure consisting of periodic GaN and AlN layers by means of chloride-hydride epitaxial growth on a hybrid SiC/Si substrate synthesized using the method of the coordinated substitution of atoms.
A comprehensive study of the heterostructure by means of nanoscale mapping of elastic strain demonstrated that in the upper GaN layer the dual-axis strain sxx is minimal (~ –0.12 GPa). There is practically no strain in the superlattices located in the upper part of the heterostructure.
Preparation of composite micro-nanofibers based on nano-sized magnetite by electrospinning
Authors: Yakupov Roman P. , Buzko Vladimir Yu. , Ivanin Sergey N. , Papezhuk Marina V.
Published: November 2024

Composite materials with magnetic fillers play an important role in a number of industries, from functional coatings in electronics to electromagnetic wave absorption and microwave-shielding materials. An important feature is the selection of a magnetic nano-sized filler that does not cause increased degradation of the polymer binder, and the selection of a polymer that ensures the weather resistance of the nanocomposite material. In this study, composite samples of micro- and nanofibers based on fabricated particles of nanosized magnetite (Fe3O4) as a cheap electromagnetic wave absorption material were investigated.
Magnetic polymer-dielectric fibers polystyrene-Fe3O4 were obtained by electrospinning. The X-ray diffraction analysis showed that the synthesized Fe3O4 nanoparticles have a cubic space group structure Fd3m with crystal lattice parameter a = 8.422±0.026 Å. The analysis of the ferromagnetic resonance spectrum showed the ferromagnetic nature of the obtained magnetite nanoparticles. It has been shown that during the production of composite fibers by electrospinning, a dispersion of nano-sized magnetite powder can be included in the spinning solution, which, as a result of the electrospinning process, allows obtaining magnetic composite micro- and nanofibers. The average size of the included magnetite particles was15±3 nm.
The resulting non-woven magnetic material is predominantly composed of two types of fibers with an average diameter of 680±280 nm and larger associated fibers with a diameter of 1500±300 nm. Based on a certain frequency ependence of losses upon reflection RL in the frequency range 15 MHz – 7.0 GHz, the synthesized fibrous material can be considered to be an effective electromagnetic wave absorption material.
Features of the local activation of aluminum in the presence of bicarbonate ions
Authors: Minakova Tatyana A. , Kaluzhina Svetlana A. , Aksyonova Evgeniya N.
Published: November 2024

The purpose of the article is to study the effect of bicarbonate ions on the local activation of aluminum at a temperatureof 25 °C.
The features of local activation of aluminum in the presence of bicarbonate ions (2·10–4–4·10–3 M) were studied using the methods of voltammetry, chronoamperometry, optical and scanning electron microscopy, and X-ray spectral microanalysis.
As a result, we established the range of sodium bicarbonate concentrations, in which there is local activation of aluminum; obtained experimental data on the dependence of the main quantitative characteristics of the process (potential of pitting formation, potential of local activation, and induction period) on the concentration of sodium bicarbonate. Formal kinetic approach was used to propose a mechanism for the local activation of aluminum in hydrocarbonate media
Anisotropy of acoustic wave attenuation in NaClxBr1-x crystals
Authors:   Arifov Institute of Ion-Plasma and Laser Technologies of Uzbekistan Academy of Sciences, Akhmedzhanov Farkhad R. , Mirzaev Sirozhiddin Z. ,   Arifov Institute of Ion-Plasma and Laser Technologies of Uzbekistan Academy of Sciences, Mustafayev Temur Sh. ,   Arifov Institute of Ion-Plasma and Laser Technologies of Uzbekistan Academy of Sciences
Published: November 2024

The acoustic properties anisotropy of lanthanum gallosilicate crystals in the frequency range from 0.4 to 1.6 GHz was studied by the Bragg light diffraction method. As a result, real and imaginary elastic constants of these crystals were determined, which were used to construct the cross-section of the velocity and attenuation surfaces of acoustic waves by the (001) plane. Propagation special directions of acoustic waves in the (100) plane have been found. The established patterns of acoustic properties anisotropy expand the using possibilities these crystals in acoustic and acousto-optic devices.
Detection and localization methods of film resistive elements for laser adjustment of their parameters, review
Authors:   PJSC Strela, Kondrashov Vladimir V. , Seredin Oleg S. ,   Tula State University, Kopylov Andrei V. ,   Tula State University, Larin Aleksander O. ,   Tula State University
Published: November 2024

Laser trimming (normalization) of film resistive elements (REs) by making adjustments to their configuration is one of the most frequently used and promising methods for tuning electrical parameters of circuits in microelectronics. Given that the geometric sizes of REs and the diameter of the laser beam are crucial initial data for resistor modeling, the necessity for analysis of the actual layout of the board is evident. The key aspect in the adjustment of film REs is precise detection and accurate determination of the RE’s position and defects within the coordinate system of the laser trimming machine using information from the video feed. The paper presents a systematic review of modern methods for detecting and localizing elements in images of microcircuit boards and hybrid integrated circuits. Literature analysis revealed that there are very few publications directly related to the task of precision detection of film resistors, except for a small number of studies. Therefore, the review also includes research on detecting and recognizing surface-mounted components, as well as defect localization on printed circuit boards.
In Memory of Alexander S. Bugayov
Authors:   Kotel’nikov Institut of Radioengineering and Electronics of RAS, Grachev Vladimir I.
Published: November 2024

Information is presented about the deceased Alexander Stepanovich Bugayov, DrSci Phys&Math, professor, Corresponding Member of the Russian Academy of Sciences since 1994 in the Department of Computer Science, Computer Engineering and Automation, full member of the Russian Academy of Sciences since 2000 in the Department of Nanotechnology and Information Technology (Section of Computing, Location, Telecommunication Systems and Element Base), founder of the Department of Solid-state Electronics and Radiophysics of the Moscow Institute of Physics and Technology, Head of the Department of Vacuum Electronics and At the same time, he is the scientific director of the MIPT Center for Open Systems and High Technologies, Head of the Laboratory of Wave Electronics of the V.A. Kotelnikov Institute of Radio Engineering and Electronics of the Russian Academy of Sciences, Deputy Director of the State Research Institute of Electronic and Ion Optics, Chief Researcher of the Department of Scientific and Innovative Activities of the South Ural State University. Professor of the Computer Engineering Department of the Higher School of Economics, Professor of the St. Petersburg State University of Aerospace Instrumentation, an outstanding specialist in the field of condensed matter physics, semiconductor physics, acoustic and spin-wave electronics, computer science and mathematical modeling of semiconductor and solid-state information processing devices. The main biographical data are given: studies at the Moscow Institute of Physics and Technology (Faculty of Physical and Quantum Electronics), postgraduate studies and work at MIPT, defense of a PhD (physical and mathematical sciences) dissertation, authorship of more than 250 scientific papers in scientific journals, participation in Russian and international conferences and seminars, editorial work in scientific journals. Work as a member of the Presidium of the Russian Academy of Sciences, membership in various Russian and international scientific societies and expert councils.
Piezoelectric sensors for studying the Moon plasma-dust exosphere
Authors:   Институт радиотехники и электроники им. В.А. Котельникова РАН, Голованов Егор В. , Кашин Вадим В. ,   Институт радиотехники и электроники им. В.А. Котельникова РАН, Горбачев Илья А. ,   Институт радиотехники и электроники им. В.А. Котельникова РАН, Захаров Александр В. ,   Институт космических исследований РАН, Дольников Геннадий Г. ,   Институт космических исследований РАН, Колесов Владимир В. ,   Институт радиотехники и электроники им. В.А. Котельникова РАН
Published: November 2024

Программа научных исследований лунных посадочных аппаратов включает эксперимент, предусматривающий изучение динамики лунных микрочастиц и параметров приповерхностной пылевой плазмы. Приповерхностная плазма и левитирующие пылевые частицы формируют плазменно-пылевую экзосферу Луны. Для регистрации механических характеристик пылевых микрочастиц необходим датчик удара. В качестве чувствительного элемента для датчика удара в работе экспериментально исследовалась ударная чувствительность различных пьезоэлектрических материалов: монокристаллов ниобата лития, пьезокерамики ЦТС-19, а также пьезополимерной пленки поливинилиденфторида. Для регистрации электрических сигналов на поверхности пьезоэлектрических датчиков разработан измерительный стенд с оригинальной топологией системы электродов на пластинах. Измерены чувствительность различных пьезоэлектрических датчиков к удару, времена отклика датчика на удар, а также координаты точек удара на пластинах датчика.
Adaptación al cambio climático a partir del empleo verde en Paraguay. Año 2023
Authors: Rodríguez Cañete Clarissa Melina
Published: November 2024

Se denomina cambio climático a la variación global del clima de la Tierra debido a causas naturales, pero principalmente a la acción humana. El reto de adaptarse a las nuevas condiciones climáticas y participar en estrategias de mitigación supone costos económicos que hacen del cambio climático un factor condicionante esencial de las características y opciones del desarrollo económico en las próximas décadas. El impacto laboral de las políticas de mitigación del cambio climático, son políticas para reducir las emisiones de gases de efecto invernadero, y las de adaptación, son políticas que predicen las consecuencias del cambio climático. Se puede decir que cuando la economía sufre, también lo hace el empleo. Sin embargo, lo difícil de analizar son los efectos que esto produce, ya que dichos efectos sobre la economía pueden no traducirse en cambios inmediatos y visibles en todos los escenarios; aunque se evidencie efectos tanto positivos como negativos en algunos sectores debido a estos cambios. Este trabajo tuvo como objetivo estudiar los empleos verdes y su adaptación al cambio climático en Paraguay, en el año 2023. Para ello, la metodología empleada fue el análisis documental bibliográfico, ya que se analiza el Índice Global de la Economía Verde (GGEI), de manera a evaluar las circunstancias favorables que permiten construir una transición hacia una economía verde. Se espera que este trabajo pueda servir como base para el estudio del empleo verde en Paraguay y de insumo a otras investigaciones del área económica.
Modelo de institución educativa sostenible para una cultura ambiental en estudiantes de primaria: Propuesta de cambio
Authors: Campoverde-Robledo Flor Nohemy , Soplapuco-Montalvo Juan Pedro
Published: November 2024

Los estudiantes de primaria muestran niveles bajos y medios de cultura ambiental debido a estilos de vida escolares inadecuados, falta de participación en prácticas ambientales, escaso compromiso con la preservación del ambiente y desconocimiento de problemas ambientales que generan hábitos negativos, entornos poco saludables y apatía hacia cuestiones ambientales, por ello se propone un modelo de institución educativa sostenible para fomentar la cultura ambiental en estudiantes de primaria de instituciones públicas urbanas de San Ignacio. La muestra fueron 338 personas, incluyendo estudiantes, directivos, docentes, administrativos y padres de familia. Se empleó una metodología descriptiva propositiva con diseño no experimental y enfoque cuantitativo, utilizando cuestionarios y análisis estadístico. Los resultados indican que, en promedio, el 70.84% de los estudiantes de la muestra presentan niveles bajos y medios de cultura ambiental determinando que la propuesta del modelo de institución educativa sostenible, validada por tres expertos, tiene un impacto positivo en la mejora de la cultura ambiental de estos estudiantes, se concluye que este modelo ofrece una valiosa contribución al campo de la educación al integrar la sostenibilidad ambiental en la planificación y gestión educativa, contribuyendo así a la formación de ciudadanos conscientes y responsables con el medio ambiente.
Nivel de conocimiento y uso de los medios de pagos digitales en Paraguay
Authors: Dávalos-von Eckstein José Edmundo , Valenzuela-Ortega Diego Fernando
Published: November 2024

La sociedad está inmersa en lo digital y el empleo de medios digitales de pagos permitió dinamizar el comercio electrónico. En Paraguay, fuera de las grandes urbes, pagar en efectivo sigue siendo el más utilizado, esto por falta de una educación digital en los habitantes; aunque, se espera que esta situación vaya revirtiéndose y se impongan los medios digitales de pagos. La metodología tuvo enfoque cuantitativo de tipo descriptivo, no experimental y de corte transversal, se utilizó una encuesta estructurada; y, los datos obtenidos fueron procesados en planilla electrónica y SPSS. La muestra por conveniencia la conforman 724 ciudadanos paraguayos de todos los departamentos del país. A través del estudio se pudo identificar lo siguiente: Existe una percepción heterogénea sobre los medios digitales de pago; 46,5% utiliza los medios digitales de pagos; 60,2% de los que utilizan medios digitales de pagos, cuentan con banca digital; 70,8% de los medios digitales de pagos se utilizan para pagar los servicios de agua, luz y telefonía; 83,6% de los medios digitales de pagos son utilizados para realizar pagos o transferencias; 23,5% de los encuestados realizó compras por internet. Además, se confirmó que no existe una relación significativa entre sexo, edad, nivel de ingreso, estudios realizados ni lugar de residencia y el uso de los medios digitales de pagos. Pero, si existe una relación significativa entre el nivel de ingreso, lugar de residencia y estudios realizados con el grado de confianza en los medios digitales de pago.
Factores relacionados con la satisfacción del cliente interno en una empresa privada. Paraguay 2023
Authors: Lezcano-Godoy Ruth Elizabeth , Penayo-Vera Virginia Lujan , Ortega-Benítez José Luis , Vázquez-Alcaraz Juan José , Servín-Pappalardo Enrique
Published: November 2024

La satisfacción del cliente interno o trabajador, en el ámbito organizacional es fundamental para el logro de un ambiente armónico y una mayor productividad, pudiendo verse afectada por diversos factores de índole económico como psicosocial. El presente trabajo se centró en identificar los factores que influyen en la satisfacción laboral de los empleados en una empresa privada en Asunción Paraguay, en el año 2023. El diseño de estudio fue cuantitativo, descriptivo, de corte transversal, el muestreo fue no probabilístico por conveniencia, donde se aplicó un cuestionario digital, en una población de 166 colaboradores de una empresa del área de capital entre los meses de abril y mayo. Los principales resultados fueron: 50,6% fueron mujeres, 54.8% de Central, 82.1% solteros, 47% es reconocido por el trabajo que desempeñan y 4.2% nunca lo han sido, se encontró asociación estadísticamente significativa entre el nivel de ingresos económicos y lo significativo del trabajo (p=0,023), la conformidad con el salario (p=0,001) y los medios y recursos para realizar el trabajo (p=0,004). El sexo y la conformidad con el salario y actividades desempeñadas (p=0,006) y medios y recursos para realizar el trabajo (p=0,031), y el nivel de formación y los medios y recursos para realizar el trabajo (p=0,003). Como conclusión, esta investigación ha demostrado que la satisfacción laboral se ve influenciada por una combinación de factores interrelacionados.
Salud mental y su implicancia sobre la voz. Relación que existe entre el estrés percibido y los síntomas vocales en estudiantes universitarios de la Facultad de Ciencias de la Salud en la Universidad Autónoma de Asunción
Authors: Alonso Juan , Moreno Abril , Ocampos Luciana , Talavera Tania , Torales José
Published: November 2024

Introducción: Según la OMS (2023), el estrés es el estado de preocupación o tensión mental generado por una situación difícil. La voz, como medio esencial de expresión, posee una fisiología compleja que se piensa refleja los estados emocionales. Por lo tanto, los síntomas vocales pueden indicar el estado emocional de las personas. Justificación: Por medio de esta investigación se pretende aportar nuevos conocimientos relacionados a la salud mental y la voz. Recordando que a nivel social se ha registrado un aumento de casos vinculados al estrés, ansiedad y bienestar posterior a la pandemia del COVID-19. Se ha demostrado que estos indicadores pueden reflejar cambios fisiológicos y repercutir en los sistemas, en este caso en particular relacionado al encargado de la producción de la voz. Objetivo: Establecer la relación que existe en la salud mental y su implicancia sobre la voz. Hipótesis: Existe una relación entre la salud mental y los síntomas vocales en estudiantes universitarios. Material y Método: Se emplearon dos instrumentos descriptivos para evaluar la autopercepción del estrés y los síntomas vocales. Además, se utilizó una herramienta complementaria diseñada específicamente para ampliar la evaluación de los síntomas vocales. Resultados: Se encontró correlaciones estadísticamente significativas en los síntomas como, sensación de nudo en la garganta, sequedad, fatiga vocal y percepción de aumento de tono e intensidad. También una diferencia en cuanto al sexo, la sequedad, opresión y nudo en la garganta se apreció más en el sexo femenino. Conclusiones: Se encontraron correlaciones estadísticamente significativas en los síntomas vocales y el estrés percibido. Estos hallazgos subrayan la importancia de considerar la salud vocal como un indicador relevante del bienestar emocional y mental en contextos académicos.