National University of Science and Technology

The sphere packing theory is used to study the influence of the particle-size distribution in the material on the porosity of briquettes and pellets, and the fractional composition of agglomerated products on the porosity of layers of such charge components. Understanding how the porosity of agglomerates varies with the particle-size distribution in the starting material, it is possible to optimize the metallurgical properties of briquette and pellets. The porosity of a layer of such products largely determines their behavior during both reduction (in blast furnaces, ore-thermal furnaces, and direct-reduction reactors) and pellet firing. The results obtained made it possible to identify for the first time the local extrema in the porosity of agglomerates and the porosity of a layer of pellets (briquettes). The developed heuristic approach can be used for optimizing the composition of mixtures for agglomeration, increasing the efficiency of pellet firing, and achieving high degrees of metallization in reducing an agglomerated charge. This approach accounts for the compressibility and shape irregularity of particles in both starting mixture and agglomerated products.

A method for simultaneous compensation of polarization drift in a fiber-optic quantum channel, and a fully fiber-optic receiver has been successfully developed, implemented, and tested using a commercial QKD system. The method is based on the exact analytical solution we derived, which gives the necessary corrective transformation for polarization. Noise and imperfections in any realistic system require iterative application of the computed corrections. In our case, polarization drift compensation was completed on average in 2-3 iterations. This is an improvement by a factor of 10-100 compared to the common methods based on hill-climbing algorithms.

Complex studies of new Mg-Zn-Y-Zr system alloys have been carried out. The content range for the formation of the two-phase structure MgSS (Mg solid solution) + LPSO (long-period stacking ordered) in alloys of the Mg-Zn-Y-Zr system was determined by thermodynamic calculations. The effect of heat treatment regimes on microstructure, mechanical, and corrosion properties was investigated. The fluidity, hot tearing tendency, and ignition temperature of the alloys were determined. The best combination of castability, mechanical, and corrosion properties was found for the Mg-2.4Zn-4Y-0.8Zr alloy. The alloys studied are superior to their industrial counterparts in terms of technological properties, while maintain high corrosion and mechanical properties. The increased level of properties is achieved by a suitable heat treatment regime that provides a complete transformation of the 18R to 14H modification of the LPSO phase.

В работе представлен метод, направленный на повышение надежности байесовского классификатора. Метод заключается в добавлении к обучающей выборке из смеси распределений двух исходных классов искусственно сгенерированных наблюдений из третьего, "фонового" класса, равномерно распределенного на компакте, содержащем неизвестный носитель исходной смеси. Такая модификация позволяет приблизить к заданному (в нашем случае к нулевому) уровню значение дискриминантной функции вне носителя распределения обучающих данных. Добавление варианта решения "Отказ от классификации", принимаемого классификатором при достаточно малых значениях дискриминантной функции, приводит к локальному повышению его надежности. В частности, такой подход позволяет решить несколько проблем: отказаться от обработки данных, сильно отличающихся от обучающих; выявлять аномальные значения во входных данных; отказаться от принятия решений в "пограничных" областях при разделении на классы. В статье приводится теоретическое обоснование оптимальности предлагаемого классификатора. Практическая ценность метода демонстрируется на задачах классификации изображений и временных рядов. Также предложена методика выделения доверенных областей, которую можно использовать для выявления аномальных данных, случаев смещения параметров распределения классов, выделения областей пересечения распределений исходных классов. На основе доверенных областей введены количественные показатели надежности и эффективности классификатора. Библиография: 23 названия.

Subject. This article analyzes pricing models in the metallurgy market and long-term contracts with price formulas. Objectives. The article aims to diagnose the current state of contracts with formula pricing, determine the reasons for the limitations in the development of these tools, and offer solutions for the transformation of the formula pricing tools. Methods. For the study, I used the results of surveys and interviews with market experts and analyzed statistical databases. Results. Based on the results of the diagnostics, the article records an overall reduction in the number of contracts with formula pricing and reveals the presence of restrictions for the previously existing formula pricing methodology based on quotations from international agencies and world market parities. The article offers certain recommendations for the development of formula pricing tools.

This study aims to investigate the potential role of antioxidants in oxidative stress and its consequent impact on the mechanical properties of neuronal cells, particularly the stress induced by amyloid‐beta (1–42) (Aβ42) aggregates. A key aspect of our research involved using scanning ion‐conductance microscopy (SICM) to assess the mechanical properties (Young's modulus) of neuronal cells under oxidative stress. Reactive oxygen species (ROS) level was measured in single‐cell using the electrochemical method by low‐invasive Pt nanoelectrode. We investigated the effects of the low molecular weight antioxidant N‐acetylcysteine (NAC) and the antioxidant enzyme superoxide dismutase 1 (SOD1) on the physiological and mechanical properties of neuronal cells using SICM. Using electrochemical method and SICM, NAC effectively reduces oxidative stress and restores Young's Modulus in SH‐SY5Y cells exposed to hydrogen peroxide and Aβ42 oligomers. Our study first examined the influence of SOD1 on intracellular ROS levels in the presence of Aβ oligomers. The investigation into the effects of SOD1 and its nanoparticle form SOD1 on SH‐SY5Y cells reveals impacts on mechanical properties and oxidative stress. The combined use of SICM and electrochemical measurements provided a comprehensive understanding of how oxidative stress, including that triggered by the Aβ oligomers affects the mechanical properties of cells.

Buryanskaya, E. L., Gradov, O. V., Gradova, M. A., Iordanskii, A. L., Maklakova, I. A., and Olkhov, A. A. (2024). Visualization and quantitative estimation of ferroelectric polymer fiber motility in time-resolved SEM using Gabor atoms. In: Advances in Transdisciplinary Engineering, volume 61, pages 689–696, IOS Press. http://dx.doi.org/10.3233/atde240821. The following brief communication discusses the possibility of applying time-resolved scanning electron microscopy methods (including Stroboscopic Scanning Electron Microscopy, Environmental Scanning Electron Microscopy, and Atmospheric Scanning Electron Microscopy) with correlation-spectral analysis in real-time for in situ measuring the mobility and mechanical properties of ferroelectric microfibers in an electric field and under the influence of ion particle beams in FIB-SEM technique or conventional electron beams in regular scanning electron microscopy. Extended periods of high temporal resolution monitoring lead to the necessity of expressing fiber mobility over time through some mathematical processing of the video stream, based on which reactivity, polarizability, conversion coefficients for piezoelectric effects in ferroelectric fibers, and dependencies of microelectromechanical dynamics on parameters of the interacting beam can be calculated. Physical “descriptors” are needed, i.e., compressed but heuristically valuable representations of time-resolved experimental data. We propose using wavelets or Gabor atoms for this purpose. The analysis is performed in real-time using the “QAVIS” software system developed by the Pacific Oceanological Institute of the Far Eastern Branch of the Russian Academy of Sciences, based on the FFTW library.

Oak is an important tree species, playing a fundamental role in many forest ecosystems. Obtaining high-quality oak planting material is a actual issue in forest biotechnology. The most promising method for this, in vitro micropropagation, faces a number of problems that can be overcome using a nanobiotechnological approach. In our work, we obtained flaky copper oxide nanoparticles with a particle size of 50–200 nm in diameter and a thickness of 10–20 nm, which were used in the WPN medium at a concentration of 0.75, 1.5, 3, 6, and 15 μg L⁻¹ at the stage of introducing the original red oak material into the in vitro tissue culture. The study demonstrated a dose-dependent antimicrobial effect: seedling sterility increased from 80% (+10% to the control) at 1.5 μg L⁻¹ CuO to 100% at doses of 3 μg L⁻¹ and higher. The maximum survival rate was observed at 3 μg L⁻¹ – 43%, which is 23% higher than the control values. At the multiplication stage, nanoparticles significantly increased plant viability – twice as much in the variant with 3 μg L⁻¹ CuO and 1.7 times when using nanoparticles and phytohormones. The combined use of nanoparticles and hormones increased the seedling height by 1.5 times and the number of additional shoots by 3 times. At the rooting stage, CuO nanoparticles did not show any rhizogenesis-stimulating effect. At the same time, phytohormones and nanoparticles stimulated root formation. At the adaptation stage, a fairly low percentage of surviving and adapted plants was observed in the control variant, while the addition of nanoparticles had a positive effect on plant adaptation. The number of surviving seedlings increased by 15%, the number of adapted ones by 10. Thus, our study showed the prospects of using CuO nanoparticles to improve the biotechnology of clonal micropropagation of red oak. In the future, these results can be used in breeding and obtaining high-quality planting material for this species.

In this paper, we present the synthesis and characterization of a rubidium vanadium(III) vanadyl(IV) phosphate, obtained under hydrothermal conditions. The new compound crystallizes in the triclinic space group P 1 ̅...

Pd²⁺ ions substituted Co-Ni spinel ferrites nanoparticles (Co0.5Ni0.5PdxFe2−xO4 (Pd→CoNiFe2O4) NSFs) have been synthesized via a hydrothermal route assisted with polyethylene glycol (PEG). XRD, SEM, TEM, HR-TEM, VSM, and Mossbauer spectroscopy were used to provide a thorough analysis of the phase and structure, magnetic characteristics, and hyperfine interactions. Magnetic features of prepared NPs showed ferrimagnetic behavior. In comparison to non-doped NPs, the incorporation of a small amount of Pd ions within Co0.5Ni0.5Fe2O4 provoked initially a slight rise in magnetization and coercivity magnitudes. Furthermore, as the Pd²⁺ ions content continued to increase, magnetization and coercivity exhibited a diminishing trend. These observations are explained by changes in size and morphology, variations in the strength of superexchange interactions, and cation redistribution. Mössbauer spectra for all samples exhibited four distinct magnetic sextets. The doped ions were substituted with Fe³⁺ ions at B site. The cation distribution was ascertained through the utilization of Mossbauer spectroscopy. An investigation of electromagnetic (EM) properties was conducted within 2–18 GHz. EM characteristics of the samples can be explained by the main contribution in EM absorption from the electric energy losses.

Studying and understanding many‐body interactions, particularly electron‐boson interactions, is essential for a deeper elucidation of fundamental physical phenomena and the development of novel material functionalities. Here, this aspect is explored in the weak itinerant ferromagnet LaCo2P2 by means of momentum‐resolved photoelectron spectroscopy (ARPES) and first‐principles calculations. The detailed ARPES patterns enable to unveil bulk and surface bands, spin splittings due to Rashba and exchange interactions, as well as the evolution of bands with temperature, which altogether creates a solid foundation for theoretical studies. The latter has allowed to establish the impact of electron‐boson interactions on the electronic structure, that are reflected in its strong renormalization driven by electron‐magnon interaction and the emergence of distinctive kinks of surface and bulk electron bands due to significant electron‐phonon coupling. Our results highlight the distinct impact of electron‐boson interactions on the electronic structure, particularly on the itinerant d states. Similar electronic states are observed in the isostructural iron pnictides, where electron‐boson interactions play a crucial role in the emergence of superconductivity. It is believed that further studies of material systems involving both magnetically active d‐ and f‐sublattices will reveal more advanced phenomena in the bulk and at distinct surfaces, driven by a combination of factors including Rashba and Kondo effects, exchange magnetism, and electron‐boson interactions.

Исследованы магнитные свойства и спектральные зависимости оптической плотности никелевых нанотрубок с золотым покрытием, полученных методом шаблонного синтеза. Изменение относительной интенсивности прошедшего через раствор нанотрубок оптического пучка в магнитном поле, перпендикулярном и параллельном ходу распространения луча, показывает возможность ориентирования нанотрубок вдоль силовых линий магнитного поля. Полученные результаты дают оценку применимости синтезированных нанотрубок для комбинированной фототермической и магнитомеханической противораковой терапии.

To alleviate the destructive alteration of the glass layer surface caused by gas evolution during the oxygen‐blocking process of the HfB2‐MoSi2‐SiC coating, CeO2 was incorporated to modify HfB2‐MoSi2‐SiC coating, and the anti‐oxidation mechanism at 1700°C in air was investigated. Compared with the unmodified HfB2‐MoSi2‐SiC coating, the addition of the refractory CeO2 to the Hf‐B‐Si‐O system leads to the formation of a stable Hf‐Ce‐B‐Si‐O complex phase glass, which substantially enhances the viscosity, stability, and self‐healing sealing properties of the glass layer. The introduction of 0.75 vol.% CeO2 significantly lowers the oxidative activity of the HfB2‐MoSi2‐SiC coating, boosting its average protective efficiency to 99.96% and reducing the maximal oxygen permeability by 43.48%, thus exhibiting superior oxygen‐blocking performance. However, excessive addition of CeO2 leads to an overabundance of oxygen release through its distinctive oxygen vacancy mechanism, which accelerates the formation of Hf‐oxides, resulting in excessive viscosity on the coating surface and leaving oxidation defects unrepaired.

The paper presents the results of numerical modeling and analysis of the stress–strain state of the epicentral zone of a strong earthquake in Northeast China that occurred on July 27, 1976, with Ms = 7.8. Many present-day works continue to discuss the reasons for such a strong earthquake, which occurred in tectonic conditions: far from interplate boundaries, inside the Tangshan tectonic block bounded by tectonic faults. However, new published geodynamic, seismological, geophysical, and geodetic data provide confidence in the determining role of fault tectonics in this region. Based on an analysis of the results of modeling of the stress–strain state preceding the Tangshan earthquake with coseismic geophysical and geodetic data, we propose an earthquake rupture formation model. The results of comparing independent shear stress estimates with the results of modeling in the sources of strong earthquakes suggest that areas of tectonic stress concentration are localized in the interfault rupture of the Tangshan fault, reaching maximum values at the termination of fault ruptures σi ≈ 50 MPa and τxy ≈ 20 MPa. The hypocenter of the main seismic event (taking into account the coordinate determination error) is located in the region of stress intensity 35‒50 MPa and a ratio of main stresses σxx/σyy ≈ 8–10. It should be expected that these zones are the rupture initiation site, the extent of which depends on the amount of accumulated elastic potential energy of tectonic stresses in the adjacent region. For the Tangshan earthquake, this area corresponds to high-intensity stresses in a band with a length exceeding 30 km and width reaching 4.5 km, exceeding 30 MPa.