Technical Physics Letters最新文献

{"title":"A New Approach to the Brachistochrone Problem with Allowance for Dry Friction","authors":"S. O. Gladkov","doi":"10.1134/s1063785024700457","DOIUrl":"https://doi.org/10.1134/s1063785024700457","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Using a new variational approach to the brachistochrone problem with allowance for dry friction, an analytically justified system of differential equations that yields the exact solution to the problem has been obtained. The dependence of the velocity on the friction coefficient has been calculated, and the parametric trajectory equation is reported.</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141866314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bifurcation Analysis of Electrodynamic Systems Containing Nonlinear Semiconductor Microstructures with Negative Differential Conductivity","authors":"G. S. Makeeva","doi":"10.1134/s1063785024700445","DOIUrl":"https://doi.org/10.1134/s1063785024700445","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Mathematical simulation of nonlinear effects of frequency multiplication in a semiconductor microstructure with negative differential conductivity (SMNDC) and parametric amplification in an SMNDC with a traveling domain in a microwave strip cavity has been performed based on the solution of a nonlinear 3D diffraction problem. The conditions of occurrence of self-oscillations in the SMNDC depending on the bifurcation parameters (bias field strength and electron concentration in the SMNDC) have been analyzed proceeding from bifurcation points of the nonlinear Maxwell operator.</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141585868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational Modeling of the Scenario of Resumption of Covid-19 Waves under Pulse Evolution in New Omicron Lines","authors":"A. Yu. Perevaryukha","doi":"10.1134/s1063785024700433","DOIUrl":"https://doi.org/10.1134/s1063785024700433","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The new COVID-19 waves in 2024 are oscillatory modes with different characteristics than those that we modeled in 2021. The global dynamics of SARS-CoV-2 infections changed its oscillation mode twice: after the global peak of Omicron BA.1 in the spring of 2022 and in December 2023 because of the appearance of the Pirola evolutionary branch. The SARS-CoV-2 outbreaks in the spring of 2024 differ from the fluctuations in the first two phases of the pandemic and waves of infections in the third phase, which began after the spread of the first version of Omicron in the winter of 2022. In the Pirola dominant branch, the situation was repeated in 2023. In 5 months, more than a dozen weak strains from the JN/KP subbranches, which became regional, were formed. The local dominant variants from the Pirola branch were again active in the regions. As a result, after the spread of the original Omicron faded, the epidemic process was restarted with new properties. The JN branch was estimated by us as having no evolutionary prospects according to the growth dynamics of its share among all infections. The reason for the aggravation of the epidemic situation is not only JN antibody evasion, but also reinfection. The spread of chronic post-Covid syndrome with a specific immunodeficiency condition has been noted. Most of the reported COVID-19 diseases in hospitals in 2024 are severe repeated infections. After the global Omicron BA.1 wave, the formation and attenuation of the wave series of local epidemics became asynchronous in nature. The continued emergence of new strains in the regions in the spring of 2024 necessitates forecasts of new methods of formal description by mathematical means of the epidemic evolution. The author consistently develops a method of computational modeling of the transformations of nonlinear oscillations in biophysical systems by analogy with discontinuous processes in technical physics. A comparative analysis of the differences in the development of the COVID epidemic waves in terms of hospitalization and mortality rates in the United Kingdom, Japan, and New Zealand has been carried out. There are different scenarios and forms of oscillatory dynamics in infections and mortality in terms of frequency, duration of COVID waves, and pauses between peaks. We have classified the scenarios according to the characteristic features of nonlinear dynamics. We have shown that the fading trend after the primary peak is easily destroyed by a mass infection event, thus causing an outbreak and a new mode of fluctuations. A method for modeling the impulse development of the epidemic based on equations with the threshold regulation functions and the choice of the forms for the situational functions damping the amplitude of infection waves has been proposed. In a hybrid structure on the right-hand side of the equations, we have indicated the rearrangements that determine the shape of the oscillating atte","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141585874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Study of the Effective Properties of Compact Bone Tissues","authors":"S. A. Lurie, G. I. Kriven","doi":"10.1134/s1063785024700378","DOIUrl":"https://doi.org/10.1134/s1063785024700378","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>In this work, we study the effective longitudinal shear properties of human compact bone tissue depending on its age group. To assess the effective longitudinal properties of bone tissue, a three-stage homogenization procedure has been developed to take into account the structural features of compact bone tissue. The obtained numerical values are in good agreement with the experimental data given by other authors. The proposed method for studying the effective shear properties of compact bone tissue is believed to provide reliable modeling of the mechanical characteristics of human bone tissue. This is necessary, for example, to choose optimal stiffness characteristics of titanium alloy prostheses, which are most suitable for implantation into the human body.</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141549468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Influence of Electron-Beam Processing on the Formation of the Structure and Surface Properties of AK10M2N Alloy Destroyed under Tensile Conditions","authors":"A. A. Abaturova, D. V. Zaguliaev, A. A. Serebryakova","doi":"10.1134/s106378502470038x","DOIUrl":"https://doi.org/10.1134/s106378502470038x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Transmission electron-microscopy methods were used to study structural-phase transformations occurring after electron-beam treatment of samples of AK10M2N alloy subjected to uniaxial tension, and the defective substructure of the samples was studied. The studies were carried out on samples of AK10M2N aluminum alloy manufactured by electrical discharge cutting that had been subjected to electron-beam processing of the surface layer and samples in the cast state to identify the dynamics of the structural-phase state and differences in destruction mechanisms. Previously, the most rational mode for irradiating samples was identified (electron beam energy density 50 J/cm², pulse duration 200 μs). A fractographic analysis of the fracture surface of samples in the cast state and subjected to electron-beam processing was performed. As a result of fractographic analysis, the mechanism of brittle fracture in cast samples of AK10M2N alloy was revealed. Foci of destruction in the structure of a brittle fracture in the form of intermetallic compounds of various shapes and structures have been identified. In the sample irradiated at an electron beam energy density of 50 J/cm² with a pulse duration of 200 μs, a fracture analysis was also carried out. The formation of an intercrystalline (intergranular) fracture after irradiation with an electron beam was revealed. A change was detected in the defective substructure of the AK10M2N alloy destroyed under tensile conditions (cast state and state formed after electron-beam processing). Electron-beam processing leads to the formation of a relatively thin surface layer represented by a submicronanocrystalline multiphase structure. Analysis of microelectron diffraction patterns made it possible to establish that the main phase located along the boundaries of crystallization cells is silicon. In addition, particles of complex composition Al₂₃CuFe₄ were discovered in the volume of crystallization cells. Based on the research that was carried out, an assumption was made about the mechanism for increasing the strength of irradiated silumin (relative to the cast state).</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141549469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Hardware–Software Complex for Diagnostics of a Human Being’s Psychophysiological State during the Solution of Cognitive Tasks","authors":"A. V. Kurbako, A. N. Hramkov, E. I. Borovkova, E. S. Dubinkina, Yu. M. Ishbulatov, V. I. Ponomarenko, A. S. Karavaev, M. D. Prokhorov","doi":"10.1134/s1063785024700366","DOIUrl":"https://doi.org/10.1134/s1063785024700366","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The psychological state of a person can change under conditions of cognitive load. Excessive cognitive load can lead to distress, which reduces performance. Diagnosis of changes in psychophysical state in the process of performing cognitive tasks is important for human health and increasing the efficiency of his work. Therefore, the purpose of the study was to develop a hardware and software complex for diagnosing the psychophysiological state of a person in the process of solving cognitive problems. Electroencephalogram signals were recorded using a developed device and a certified standard recorder during a biological experiment. A comparison was made of the diagnostic capabilities of the developed hardware–software complex and a serial device. A hardware–software complex has been developed for diagnosing the psychophysiological state of a person in the process of solving cognitive problems using an electroencephalogram signal. The developed system showed sensitivity and specificity values close to those of the serial recorder. Using the developed complex, the electroencephalogram channels suitable for diagnosing the psychophysical state were selected. The developed hardware–software complex can be used to diagnose the psychophysiological state of a person in the process of performing cognitive tasks.</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141549336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving the Method for Simulating the Evolution of SAR-CoV-2 in the Form of Hybrid SIR Models for Predicting New COVID-19 Waves","authors":"A. Yu. Perevaryukha","doi":"10.1134/s1063785024700354","DOIUrl":"https://doi.org/10.1134/s1063785024700354","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Methods for computational study of the epidemic process resumed in 2024 due to the new SAR-CoV-2 branch and the Pirola wave are discussed. The epidemic modeling technique based on various compartmental SIR systems with the reflection of transitions according to the scheme between the epidemic statuses of individuals is compared with the analysis of the rapidly emerging Pirola wave of the spreading updated coronavirus. The inclusion of physical oscillators of second-order nonlinear equations into a SIR system has been considered a way to modify the epidemic models, but their complex modes and randomization do not correspond to the epidemic course. To simulate changes in the trends in nonlinear effects of the biophysical processes experiencing pulsating variations caused by the evolution of the virus, approaches based on modification of the technical physics models, e.g., the Korteweg‒de Vries equation, have been used. The results of the computational experiments with the model cannot be considered as a sufficient result. The consistency of the computations has not been justified. The author has proposed to expand the structure to 12 statuses in relation to COVID. It is shown that expanding a set of possible statuses in a SIR system of differential equations that describe transitions between statuses of population members characteristic of COVID does not lead to the appearance of damped oscillatory modes interrupted by a new outbreak. In the field of forecasting the spread of new infections, not all factors will be established in the near future. Classical epidemic models, even with a fundamental extension of the linear SIR framework, are not suitable for the aspects of nonlinearity and pulse generation of COVID infection chains unless they include infected and immune thresholds and a lag factor. It has been substantiated that the method for expanding SIR systems does not have prognostic prospects. It is shown that the emergence of new branches of the Omicron BA strains in 2021 and JN in 2023 led to the qualitative transformation of the shape of oscillations and not just the peak amplitude. The interval between a peak and minimum has increased, i.e., not only one of the SIR model parameters has changed. According to the analysis of our data, in the winter and spring of 2024, the transition to the third mode of oscillations of infection cases during the pandemic period is implemented. In several countries, antiepidemic restrictions were completely removed in the spring of 2023, which allowed us, based on the course of new waves in 2024, to analyze the effect of the mask mandate and lockdown factors. It has been confirmed that these strict measures did not change the epidemic situation, in which the transmissibility rate exceeds a critical threshold value. A scenario for the development of the epidemic models based on hybrid predicatively redefined systems of equations is proposed, which takes into","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141552772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mathematical Modeling of Diffraction and Parametric Instability Thresholds for Magnetic Nanostructures Based on Magnetically Functionalized Carbon Nanotube Arrays","authors":"G. S. Makeeva","doi":"10.1134/s1063785024700421","DOIUrl":"https://doi.org/10.1134/s1063785024700421","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Using a developed computational algorithm based on multilevel recomposition of autonomous blocks with Floquet channels, mathematical modeling of diffraction of the fundamental mode has been carried out on a magnetic nanostructure based on a 3D array of magnetically functionalized carbon nanotubes (MFCNTs) in a waveguide depending on the bias field under the ferromagnetic resonance conditions in the millimeter wavelength range. Using the developed special computational algorithm for determining bifurcation points of the nonlinear Maxwell operator (Maxwell’s equations together with the Landau‒Lifshitz equation), the thresholds of parametric excitation of the non-exchange magnetostatic waves and dipole-exchange spin waves in a periodic 2D array of MFCNTs have been calculated depending on values of the bifurcation parameters (pump wave amplitude and frequency).</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141549338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modern Approaches to the Description of the Dynamics of Cavitation Bubbles and Cavitation Clouds","authors":"I. M. Margulis, V. N. Polovinkin, A. I. Yashin","doi":"10.1134/s1063785024700408","DOIUrl":"https://doi.org/10.1134/s1063785024700408","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The article deals with the modeling of high-energy cavitation processes, such as shock waves, cavitation erosion, bubble glow (sonoluminescence), etc., in a high-intensity acoustic field. It is shown that the well-known model based on the Keller–Miksis and Bjerknes equations does not correspond to a number of experimental data obtained in the study of a “single” cavitation bubble pulsating motionlessly in the antinode of a standing wave and an “ordinary” bubble moving in a cavitation cloud. To eliminate these inconsistencies, a new system of equations is proposed, which additionally takes into account the nonequilibrium processes of vapor evaporation and condensation and the imperfection of the vapor–gas mixture in the bubble, as well as the translational motion of the bubble. It is shown that with rapid compression of the bubble, the vapor inside it does not have time to condense and strongly damps this compression. The resulting equation explains the strong dependence of the intensity of “single” bubble glow on the temperature of the liquid. Contradictions in the description of the translational motion of bubbles associated with the application of the Bjerknes equation are eliminated. It is shown that a translationally moving bubble is compressed much weaker than a stationary one, since in the compression phase the energy of the radial motion of the bubble flows into the energy of translational motion. This allows us to explain the reason for the difference in the mechanisms of light emission from bubbles of different types. A “single” bubble emits light at maximal compression due to heating of the vapor–gas mixture up to 5000–10 000 K. Bubbles in a cavitation cloud move progressively, and their glow, in the absence of strong compression, is caused by micro-discharges in the vapor–gas phase during deformation of the bubble surfaces.</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141552773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural Change in Co–Cr–Fe–Mn–Ni Alloys upon Variation in Mn and Fe Concentrations","authors":"I. A. Panchenko, V. K. Drobyshev, S. V. Konovalov, D. A. Bessonov","doi":"10.1134/s1063785024700391","DOIUrl":"https://doi.org/10.1134/s1063785024700391","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Co–Cr–Fe–Mn–Ni alloys with a change in the manganese and iron concentrations from 5 to 35 at % providing the optimum ratio between the strength and ductility have been investigated. Using a comprehensive study of the structure and mechanical properties of the samples, data on the effect of the elemental composition on the micro- and nanohardness of the Co–Cr–Fe–Mn–Ni alloys have been obtained and an optimum Mn-to-Fe ratio ensuring high strength has been determined. The structure and the phase and chemical compositions of the materials have been examined by X-ray diffraction analysis and scanning electron microscopy.</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141549470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}