https://rep.bntu.by/handle/data/143219 2026-04-04T08:15:35Z 2026-04-04T08:15:35Z Бельков, М. В. Кацалап, К. Ю. Ходасевич, М. А. Королько, Д. А. Асеев, А. В. https://rep.bntu.by/handle/data/143362 2024-05-23T16:04:10Z 2024-01-01T00:00:00Z

Калибровка состава низколегированных сталей интервальным методом частичных наименьших квадратов по эмиссионным спектрам низкого разрешения с коррекцией базовой линии Бельков, М. В.; Кацалап, К. Ю.; Ходасевич, М. А.; Королько, Д. А.; Асеев, А. В. Экспрессное определение элементного состава сталей и сплавов на основе железа является актуальной задачей, для решения которой может применяться лазерно-искровая эмиссионная спектроскопия. Недостатком одно- или многопараметрических решений этой задачи является их полуколичественный характер. Целью работы являлась разработка количественных многопараметрических калибровок концентраций набора химических элементов, достаточного для проведения идентификации низколегированных сталей по эмиссионным спектрам низкого разрешения. Для построения калибровок применялся многопараметрический метод частичных наименьших квадратов. Уменьшение влияния избыточности широкополосных эмиссионных спектров на результаты количественного анализа достигалось путём поиска комбинации движущихся окон, содержащих на одну спектральную переменную больше, чем оптимальное количество латентных переменных для широкополосной многопараметрической модели. Также для повышения точности калибровок использовалась коррекция базовой линии с помощью адаптивного метода наименьших квадратов со штрафом и итеративным пересчётом весов. По лазерным эмиссионным спектрам 65 эталонных образцов низколегированных сталей, зарегистрированным в диапазоне длин волн 172– 507 нм со спектральным разрешением 0,5 нм и шагом 0,1 нм, получены калибровки концентрации углерода со среднеквадратичным отклонением не хуже 0,059 % в диапазоне до 0,8 %, марганца – 0,02 % и 2,0 %, соответственно, хрома – 0,009 % и 1,0 %, кремния – 0,021 % и 1,2 %, никеля – 0,04 % и 0,8 %, меди – 0,019 % и 0,5 %, ванадия и титана – 0,005 % без ограничения диапазона. Полученные многопараметрические модели являются количественными для указанных элементов, что позволяет определять сорт исследуемых сталей экспрессным образом на производстве или при их вторичной переработке.

2024-01-01T00:00:00Z Lapitskaya, V. A. Kuznetsova, T. A. Chizhik, S. A. https://rep.bntu.by/handle/data/143361 2024-05-23T16:04:10Z 2024-01-01T00:00:00Z

Determination of Crack Resistance of the Cover and Slide Glass by Indentation Method with the Visualization Using Atomic Force Microscopy Lapitskaya, V. A.; Kuznetsova, T. A.; Chizhik, S. A. Crack resistance of two types of glass was studied – cover glass (0.17 mm thick) and slide glass (2 mm thick) using an improved technique through the use of the probe methods, which makes it possible to increase the accuracy of determining the crack resistance of glass. Colorless silicate glass was used. Crack resistance was determined by the Vickers pyramid indentation method. Microstructure of glasses surface and deformation region after indentation were studied using an atomic force microscope. Mechanical properties of glasses were determined by nanoindentation. Surface relief of a glass slide is rougher than that one of a cover glass. Roughness Rz for a cover glass is less than for a slide glass. Specific surface energy value of 0.26 N/m is higher for the slide glass compared to the coverslip. One elastic modulus value E of the cover glass is 48 GPa, and that one of the slide glass is 58 GPa. The microhardness value H is almost the same for by the glasses and amounts to 6.7 GPa for a slide glass and 6.4 GPa for a cover glass. Atomic force microscope images of deformation region after indentation with a Vickers pyramid show that the first cracks appear at a load of 1 N on the slide glass, and at 2 N on the cover glass. At a load of 3 N, the cover glass is destroyed. Based on the results of crack resistance calculations it was found that critical stress intensity coefficient KIC values are 1.42 MPa∙m1/2 for a glass slide, and 1.10 MPa∙m1/2 for a cover glass.

2024-01-01T00:00:00Z Yasukevich, A. S. Kisel, V. E. Trusova, E. E. Rachkovskaya, G. E. Zakharevich, G. B. Podbolotov, K. B. Gurin, V. S. https://rep.bntu.by/handle/data/143360 2024-05-23T16:04:09Z 2024-01-01T00:00:00Z

Determination of the Concentration of Tm3+ and Ho3+ Ions in the Glass and Crystalline Phases in Oxyfluoride Glass Ceramics by Absorption Spectra Analysis Yasukevich, A. S.; Kisel, V. E.; Trusova, E. E.; Rachkovskaya, G. E.; Zakharevich, G. B.; Podbolotov, K. B.; Gurin, V. S. Optical glass ceramics based on oxyfluoride glasses activated by rare earth ions have attractive properties for development of lasers and near-infrared amplifiers, since they combine properties of fluoride crystals with low phonon frequencies and chemical and mechanical properties of oxide matrices. Spectroscopic properties of activator ions in crystalline and glass phases of glass-ceramics can differ significantly. Thus, it is possible to determine impurity ions’ distribution between these phases by means of absorption or luminescence spectra analysis. The main goal of this work was to develop a method for determining the concentration of Tm3+ and Ho3+ ions in the crystalline, PbF2 and glassy phases of glass ceramics after secondary thermal treatment of thulium-doped and thulium-holmium co-doped oxyfluoride glasses. Spectroscopic characteristics of oxyfluoride glasses activated by Tm3+ ions and co-activated by Tm3+ and Ho3+ ions, as well as glass ceramics obtained from the original glasses as a result of secondary heat treatment were studied. It was established by X-ray phase analysis method that under certain heat treatment conditions crystalline β-PbF2 phase is formed in those glasses. Absorption and luminescence spectra of Tm3+ and Ho3+ impurity ions in the original glass and in β-PbF2 crystals were compared with their ones in glass ceramics. A method for determining the concentration of ions in the crystalline and glass phases of glass ceramics was proposed on the basis of this comparison. Dependence of Tm3+ and Ho3+ ions distribution between the glass and crystalline phases on different regime of glasses' secondary heat treatment was studied.

2024-01-01T00:00:00Z Stepanov, M. S. Koshlyakova, I. G. https://rep.bntu.by/handle/data/143359 2024-05-23T16:04:08Z 2024-01-01T00:00:00Z

Temperature Measuring Method Accuracy Evaluation in the Microarc Heating Process Based on Reproducibility and Uncertainty Indicators Stepanov, M. S.; Koshlyakova, I. G. It is necessary to control temperature using thermoelectric sensors for steel products surface alloying in conditions of microarc heating. The using S-type thermocouples possibility has been substantiated, main factors affecting the measurement results have been established, and the the reproducibility index functional dependence on the measured temperature has been determined, as a result of previous studies. However, additional influencing factors that may affect to the heating process kinetics and the temperature measurements results were not taken into account. The purpose of the work was a steel temperature measurement results uncertainty generalized assessment during microarc heating, taking into account most complete influencing factors set. Influencing factors comprise: average coal powder particle size (X1), sample diameter (X2); chromium content in steel (X3 ). The measurement error was denoted Y. The dependence is obtained: Y = –4.032X1 – 0.095X2 + 0.0058X3 + 3.414. Thus, in the studied range of values, an increase in the powder particle and the samples diameter size leads to a decrease in the measurement error, and the chromium content increase leads to its increase. Therefore, the temperature measurement error during microarc heating can be reduced with decrease the sample heating rate, as well as with increase the heat transfer intensity from its surface to the material depth due to an increase the size, and, accordingly, the processed products mass. Next, the studied factors values distribution laws were evaluated. For X1 and X2, the normal distribution law is adopted, for X3 – uniform. Taking into account each factor's influence coefficients, and the total uncertainty estimate introduced assessment by them, a generalized uncertainty estimate was found: U = 1.1 °C. The microarc heating temperature measurement method quantitative assessment detailed of the accuracy makes it possible to take into account all significant influencing factors and their total measurement uncertainty contribution. The obtained temperature measurement's total uncertainty value from the three studied factors can be used as a priori information as a type B uncertainty during the microarc saturation process.

2024-01-01T00:00:00Z