https://rep.bntu.by/handle/data/113820 Wed, 22 Apr 2026 15:28:19 GMT 2026-04-22T15:28:19Z https://rep.bntu.by/handle/data/113854 Структуроскопия витков пружин после высокотемпературной механической обработки на основе измерения скорости рэлеевских волн Муравьев, В. В.; Гущина, Л. В. Для изготовления рессорных пружин подвижного состава (вагонов, локомотивов, автомобилей) применяют прутки из пружинных сталей. При высокотемпературной механической обработке при навивке пружин и их закалке возникает различие в скоростях охлаждения внутренней и наружной сторон витков пружины, что приводит к различию в структурном состоянии и сказывается на долговечности пружин. Цель работы – исследование влияния структурных изменений в наружной и внутренней поверхности витков пружин рессорной стали после операций навивки и высокотемпературной механической обработки на измеряемые характеристики рэлеевских акустических волн. Исследованы скорости распространения рэлеевских волн в рессорно-пружинной стали 60С2А после операций навивки и высокотемпературной механической обработки. Для исследований использованы теневой метод и метод автоциркуляции с пьезоэлектрическими преобразователями ЦТС-19 частотой 5 МГц с конструкцией специального блока. Преобразователи обеспечивают ввод и приём рэлеевской волны по внутренней и наружной образующей поверхности пружины. Показано, что метод сравнения результатов измерения скорости рэлеевских волн на фиксированной базе по образующей витка на внутренней и внешней поверхностях пружины чувствителен к нарушениям в структуре материала и появлениям дефектов. Найдена однозначная связь структурных состояний на внешней и внутренней стороне пружины со скоростью рэлеевской волны. В результате проведённых измерений сделан вывод о значимой чувствительности рэлеевских волн к структурному состоянию исследуемой стали. Обнаружен рост скорости волны на внутренней поверхности витка в зоне контакта с оправкой относительно внешней стороны витка, сигнализирующий о неполной закалке стали в этой зоне в процессе высокотемпературной механической обработки. Относительная разница скоростей в разных образцах пружин составляет приблизительно до 1 % (≈ 30 м/c), что является значительной величиной для оценки качества высокотемпературной механической обработки. Sat, 01 Jan 2022 00:00:00 GMT https://rep.bntu.by/handle/data/113854 2022-01-01T00:00:00Z https://rep.bntu.by/handle/data/113853 Probability of Erroneous Data Registration in a Single Photon Erasure-Type Communication Channel with a Receiver Based on a Photon Counter Timofeev, A. M. When measuring low-power optical signals, it is necessary to ensure the highest reliability of the received data, which is especially important for single-photon communication channels. This determines the expediency of using photon counters as receiving modules for such channels. They are highly sensitive, but are characterized by data recording errors. Therefore, the purpose of this work was to investigate the influence of the intensity of the registered optical radiation J0 during the transmission of binary symbols “0” on the probability of registering symbols “1” at the output of the communication channel in the presence of symbols “0” at its input P(1/0). The statistical distributions of the mixture of the number of dark and signal pulses at the output of the photon counter during the registration of binary symbols “0” Pst0 (N ) were determined. To do this, a technique was used to reduce information loss. As a result, the minimum probability P(1/0) was reached. The probabilities P(1/0) were calculated for a communication channel containing a photon counter as a receiving module. This calculation was carried out at different values of the supply voltage of the avalanche photodetector U and the intensity of the optical signal used to transmit the binary symbols “0” J0 . The experimental results showed that with increasing optical signal intensity J0 , the dependences P(1/0) on J0 initially remain almost unchanged and retain a constant value. However, with a further increase in J0 , there is a linearly increasing character of the dependences P(1/0) on J0 . Moreover, with other equal reception parameters, such a character of the dependences P(1/0) on J0 begins to manifest itself at higher intensities of the optical signal J0 with an increase in the supply voltage of the avalanche photodetector. Sat, 01 Jan 2022 00:00:00 GMT https://rep.bntu.by/handle/data/113853 2022-01-01T00:00:00Z https://rep.bntu.by/handle/data/113852 Dynamic Features of Spectra of Single and Quasi-Periodic Measuring Signals Suchodolov, U. V.; Isaev, A. V.; Sheinikau, A. A. Solving the problems of spectral processing of single and quasi-periodic signals in measurement and diagnostic systems is directly related to their isolation against the background of external interference or noise. The purpose of this work was to study single and quasi-periodic signals, i. e. signals limited in time, presented as separate components; development of a mathematical apparatus that connects the individual components of the original, time-limited signal, with the spectral characteristics of the periodic signal, which is obtained from the original by its periodization. The paper analyzes the spectrum of a quasi-periodic signal, which is presented from spectral density regions separated by spectral components with zero amplitude. The process of signal periodization is considered on the example of unipolar rectangular pulses. The representation of the analyzed complex single signal in the form of a linear combination of given functions, limited in time by the duration of the considered signal, was chosen, and it was determined that it is most logical and efficient to use radio-frequency pulses. The spectral density of the signal under consideration is presented as the sum of the spectral densities of radio-frequency pulses of the same width with a varying carrier frequency. The original signal is presented as the sum of the constituent components (radio-frequency pulses), which form a time-limited frequency spectrum – a quastr. As a result, the correlation of the considered quasi-periodic signal with the parameters of the periodic signal (amplitude, period, and initial phase) is shown. A format for representing time-limited signals in the form of components related to the spectral characteristics of a periodic signal, obtained from the original signal by periodization, has been developed. The formed mathematical apparatus allows simplifying the algorithmic support of measuring systems by eliminating the correlation signal processing. Sat, 01 Jan 2022 00:00:00 GMT https://rep.bntu.by/handle/data/113852 2022-01-01T00:00:00Z https://rep.bntu.by/handle/data/113851 An Approach to Monitoring of Magnetic Parameters of Cores of a Chain of Spheres. Diagnostics of Different Chain’s Length and Core’s Radius Sandulyak, A. A.; Sandulyak, D. A.; Gorpinenko, Y. O.; Sandulyak, A. V.; Ershova, V. A. The basic structural elements of the magnetized granular medium (effectively used, in particular, in apparatus of thin magnetic separation) are granule chains (according to channel-by-channel model), in connection with which there is a need to detail the features of their magnetization. The purpose of the work is to develop and implement an approach to measuring magnetic (micro)flows along the cores of different radius r in the chain of granules using a specially developed (by printed circuit board technology) sensor, with high radius R (15 and 20 mm) spheres available for such measurements. From the data of measuring magnetic (micro)flows data of average induction in each of the quasi-continuous cores of the spheres chain are obtained, as well as data of magnetic permeability and susceptibility of these cores, their magnetization for different values of the intensity of the magnetizing field. It is shown that dependences of mentioned magnetic parameters from number n spheres in a chain are generalized on r /R for different R. These relationships, increasing as n increases due to a decrease in the demagnetizing factor N of any of the cores and the chain as a whole, demonstrate the achievement of individually limiting values of magnetic parameters and corresponding auto-model regions where N→0. At the same time, the transition to each of these regions, manifesting almost independently of r /R and intensity, falls on the value of n = 10–12 = [n]. Thus, in fact, such a criterion value [n] distinguishes chains by sufficiently “long” – when n ≥ [n] and “short” – when 2 ≤ n ˂ [n]. Data of demagnetizing factor for different cores of “short” chains of spheres are obtained and phenomenologically described. Sat, 01 Jan 2022 00:00:00 GMT https://rep.bntu.by/handle/data/113851 2022-01-01T00:00:00Z