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One of the ways to increase the energy efficiency and intensity of blast furnace smelting, especially when using pulverized coal fuel, is to increase the hot strength of coke. In the conditions of OJSC NLMK, an oil additive was introduced into the coal charge to improve the coke quality. At the same time, sulfur content in the coke increases, and, consequently, sulfur content in the cast iron increases as well. In this regard, the task of finding ways to improve the desulfurization of cast iron in blast furnace becomes urgent. The main factors determining the desulfurization of cast iron are slag basicity, content of MgO oxide in it, temperature of the smelting products, and the slag viscosity. The purpose of this work was to compare the efficiency of sulfur removal by increasing the slag basicity and MgO content. On the basis of well-known equations, an algorithm was developed that allows the problem to be solved. It was established that an increase in MgO content in the slag promotes desulfurization of cast iron to a greater extent than a basicity increase. In addition, an increase in MgO content by 1 % is accompanied by an increase in slag yield by 3.0 – 3.5 kg/t of cast iron. At the same time, an increase in basicity by 0.01 leads to an increase in the slag yield by 4 – 5 kg/t of pig iron. Consequently, reducing the sulfur content in pig iron by increasing the slag basicity requires less heat. In terms of the specific consumption of coke, difference in heat demand is 0.4 – 0.5 kg/t of pig iron. It is shown that with an increase in MgO content in the slag, the slag viscosity at a temperature of 1450 °C increases to a lesser extent than with an increase in basicity. © 2020 National University of Science and Technology MISIS. All rights reserved.

The aim of the study ��� to determine the variants of SARS-CoV-2 virus in the inter-peak period (before the beginning of the new wave) in patients of Kharkiv and Kharkiv region with confirmed SARS-CoV-2 infection. Materials and methods. The smears (40 nasopharyngeal samples) from patients with symptoms of ARVI or suspected COVID-19, who were hospitalized to MNE KRC "Regional clinical infectious diseases hospital" in June 2021 and who were identified as positive for SARS-CoV-2 were used study for research conducting. Cross-sectional study of the detection of variants of SARS-CoV-2 circulating in the Kharkiv region in June 2021 was conducted. According to the method of systematic probabilistic sampling for the study of genetic variability of SARS-COV-2, 40 patients with COVID-19 were selected. Among the studied patients, females predominated ��� 25 people against 15, respectively. The average age of patients was 60.4 years (minimum - 25 years, maximum - 91 years). All patients were hospitalized in the presence of respiratory failure, but community-acquired pneumonia was visualized instrumentally (computed tomography, radiography, ultrasound) in 38 patients. Clinical group III was established in 21 patients, clinical group IV ��� in 17. Mortality among the studied group was 15%. Research results. The predominant circulation of variant 201/501Y.V1 (alpha) was detected during PCR studies on variants of SARS-CoV-2 virus circulating in Kharkiv and the Kharkiv region in the inter-peak period (before the beginning of the third wave). Alpha variant was detected in 35 patients (87.5%) with typical for this virus mutation ��� N501Y, but the presence of additional mutations was identified in 1 patient. The original SARS-CoV-2 virus was detected in 5 patients (12.5%), but in 1 of them with the presence of the N501Y mutation. Circulation of only variant 201/501Y.V1 was detected in all residents of the region. Circulation of SARS-CoV-2 variants 20H/501Y.V2 (beta), 20J/501Y.V3 (gamma), 20C/S.452R (previously epsilon) was not detected in Kharkiv and the region, and the E484K mutation was not found in any patient. Conclusions. The dominant variant circulating in Kharkiv and the region in the inter-peak period is the alpha variant, which prevails over the original virus due to the increased level of contagiousness and more rapid spread., {"references":["1.\tWorld Health Organization. Tracking SARS-CoV-2 variants. Last updated 23 July 2021. URL: https://www.who.int/en/activities/tracking-SARS-CoV-2-variants (дата звернення: 02.08.2021).","2.\tDiagnostic kit «Biocore® SARS-CoV-2» URL: https://biocor-tech.com/wp-content/uploads/2021/04/biocore-sars-cov-2_100.pdf","3.\tSNPsig® VariPLEX™ (Covid-19) D00060 IFU Issue 1 Published Date: 26th March 2021 Primerdesign Ltd. URL: https://genesig.com/assets/files/SNPsig_VariPLEX_Covid_19_IFU_Issue_1_1.pdf","4.\tZhukova A., Blassel L., Lemoine F., et al. (2020). Origin, evolution and global spread of SARS-CoV-2. C R Biol. 2020 Nov 24. doi: 10.5802/crbiol.29.","5.\tDaily new confirmed COVID-19 cases per million people. COVID-19 Data Repository by the Center for Systems Science and Engineering at Johns Hopkins University. Last updated 23 July 2021. URL: https://github.com/CSSEGISandData/COVID-19.","6.\tDavies N.G., Abbott S., Barnard R.C. et al. (2021). \"Estimated transmissibility and impact of SARS-CoV-2 lineage B.1.1.7 in England\". Science. 372 (6538): eabg3055. DOI:10.1126/science.abg3055.","7.\tV'kovski P., Kratzel A., Steiner S. et al. (2020) Coronavirus biology and replication: implications for SARS-CoV-2. Nat Rev Microbiol. 2020 Oct 28; Р. 1–16. URL: www.nature.com/nrmicro."]}

The conditions have been established for detection and recognition of rotation domains in α-Ga2O3/α-Al2O3 (0001) thin films in the presence of other polymorphs. The domains are visualized by high-resolution transmission electron microscopy. Their structural characteristics are determined by preparing cross-sectional and plan-view specimens, choosing the correct diffraction conditions and proper imaging modes. As a result, the dimensions, the spatial distribution, the volume fraction and area fraction of the inclusions of domains have been determined. Keywords: structural defects, rotational domains, transmission electron microscopy, gallium oxide.

Increase in the intensity of blast furnace smelting at NLMK JSC is achieved by improving quality of coke and iron ore materials, by increasing pressure under the blast furnace mouth and by oxygen enrichment. It is accompanied by an increase in the rate of wustite indirect reduction and decrease in specific heat losses with cooling water. However, the risks of burden yield problems are significantly lower with high intensity. It has been established that with the change in quality of charge materials, reason for burden yield problems can be also the variation in ore load ratio along the furnace radius. A new method for diagnosing causes of burden yield problems was developed. Using method of mathematical modeling, effect of change in ore load and size of iron-ore materials on peripheral gases temperature change and the degree of CO use were analyzed. The method is based on analysis of joint change in gas temperature and degree of CO use in peripheral area. Analysis of peripheral gases temperature variation and degree of CO use makes it possible to identify reasons of pressure drops along the furnace height. As a result of analysis of pressure drops dynamics changes along the furnace height, there have been found signs that can be used to judge the probability of burden yield problems. The possibility of reducing pressure drops due to redistribution of ore load along the furnace radius and the amount of gases is considered. It is shown that various methods of reducing the amount of gases are accompanied by different changes in coke consumption and furnace productivity. Mathematical model has been developed to select the best combination of parameters changing of the fuel-enriched blast in specific conditions. © 2018, National University of Science and Technology MISIS. All rights reserved.

Structural features of the interface between a semipolar gallium nitride layer and buffer layer of aluminum nitride grown on a SiC/Si(001) template misoriented by an angle of 7 were studied by high-resolution transmission electron microscopy. The effect of interface morphology on the structural quality of the gallium nitride layer was revealed: faceted structure of the buffer layer surface reduces the threading dislocations density. Keywords: semipolar GaN, transmission electron microscopy, dislocation, Si(001) substrate

We report a novel approach for metal organic vapor phase epitaxy of (Al)GaN heterostructures on Si substrates. An approximately 90-100nm thick SiC buffer layer is synthesized using the reaction between Si substrate and CO gas. High-resolution transmission electron microscopy reveals sharp crystalline interfaces with epitaxial relationship between SiC/Si and AlN/SiC layers. Optimization of SiC morphology and AlN seed layer thickness facilitates the growth of GaN layers free of pits (v-defects). It is also found that Si doping eliminates these defects in the case of growth on SiC templates with non-optimized surface morphology. Thus, synthesis of thin SiC buffer layer is suggested as a solution for the interface problems at the initial stage of III-N on Si epitaxy.