Technical Physics最新文献

{"title":"Hybrid Model of Reproductive Process of Subpopulation Groups of Sturgeon (Acipenseridae) in the Caspian Sea on the Basis of Immunological Analysis of Their Adaptive Differences","authors":"A. Yu. Perevaryukha","doi":"10.1134/S1063784223030015","DOIUrl":"10.1134/S1063784223030015","url":null,"abstract":"<p>The paper is devoted to computational modeling of biophysical processes with factors of heterogeneous adaptation. Plasticity and variability is the basis of evolution in natural biophysical systems. The complex of behavioral and biochemical adaptations allows the ancient populations of the Caspian Sea to efficiently use the limited resources and withstand the competition. During long-term simultaneous evolution in populations of Caspian organisms, a specific adaptation has appeared that is the strategy of survival optimal for physical conditions of the Caspian Sea. Interference in the existing hydrological systems of the region instantaneously deteriorated the advantages of the evolution strategy. An important form of adaptation for the Caspian Sea is the formation of subpopulation reproductively isolated groups that become units of species formation, accumulating the differences because of the reproductive isolation. In the paper we describe the method for analyzing the intrapopulation structure, where the groups with different reproductive behavior arose in the population. This is an aspect of the technical problem of the method for their introduction. A modified method of antigen differentiation developed by Yu.N. Perevaryukha (patent for invention RU 2253970) allowed determining the belonging of animal units to one of the reproductive groups of marine sturgeons by the differences in their antigens in the blood serum. It was shown that biophysical adaptation to long-term life in sweet water reflects in the presence in blood of specific proteins called the antigen markers. Immunochemical technologies immunodiffusion and electrophoresis are applied to study the markers of reproductive groups of Caspian sturgeons. The knowledge about the character of life cycle of groups isolated by their reproductive behavior and optimal temperature is necessary for artificial recovery of the populations. The data on the presence of two reproductive groups in starry sturgeon <i>Acipencer stellatus</i> are used to model the reproductive activity of the population. The information about the degree of intrapopulation differentiation allows improving the hybrid computational structure for the model of biophysical processes requiring the animal unit introduction technology; this structure was earlier proposed by us in <i>Technical Physics</i>. The model scenario explains the low efficiency of artificial release of sturgeon fish in the Caspian Sea. The procedure for reintroduction of sturgeons into the Caspian Sea must take into account the reproductive peculiarities of groups with different behavior. The considered problem is topical not only for populations of the Volga basin, but also for local populations in southern waters of the Caspian Sea of Iran and Azerbaijan.</p>","PeriodicalId":783,"journal":{"name":"Technical Physics","volume":"68 3","pages":"47 - 58"},"PeriodicalIF":0.7,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46047692","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 Formation of Au Nanoparticles in SiO2–TiO2 Films by Local Electrochemical Reduction Using an Atomic Force Microscope Probe","authors":"V. D. Krevchik,&nbsp;D. O. Filatov,&nbsp;M. B. Semenov","doi":"10.1134/S1063784223020068","DOIUrl":"10.1134/S1063784223020068","url":null,"abstract":"&lt;p&gt;The aim of this work is to experimentally investigate the features of the formation of Au nanoparticles (NPs) in SiO&lt;sub&gt;2&lt;/sub&gt;–TiO&lt;sub&gt;2&lt;/sub&gt; films by the method of local electrochemical reduction using an atomic force microscope (AFM) probe. The study has the additional aim of establishing the modes of the formation of Au NPs, which provide controlled production of NPs with specified parameters. The created scientific and technical products are intended for use in nanoelectronics, integrated optics, optoelectronics, and plasmonics to create new nanoelectronic devices based on MNP arrays embedded in dielectric films, metal nanoantennas of arbitrary shape embedded in optical dielectric waveguides based on thin-film structures, etc. (The relevance of ongoing research is related to this.) An experimental study of the formation processes of individual Au NPs in the thickness of SiO&lt;sub&gt;2&lt;/sub&gt;–TiO&lt;sub&gt;2&lt;/sub&gt; films has been carried out by the method of local electrochemical reduction of Au(III) ions using an AFM probe. Au NPs have been formed in SiO&lt;sub&gt;2&lt;/sub&gt;–TiO&lt;sub&gt;2&lt;/sub&gt; films using a SolverPro atomic force microscope manufactured by Nanotechnology-MDT (Zelenograd, Russia) in the contact mode. We have used AFM cantilevers made of Si with Pt coating by Nanotechnology-MDT CSG-01. Before the formation of Au NPs, AFM images of a selected area of the gel-film surface have been measured: &lt;i&gt;z&lt;/i&gt;(&lt;i&gt;x&lt;/i&gt;, &lt;i&gt;y&lt;/i&gt;), where &lt;i&gt;x&lt;/i&gt; and &lt;i&gt;y&lt;/i&gt; are the coordinates of the AFM probe tip in the sample surface plane and &lt;i&gt;z&lt;/i&gt; is the surface height at the point with coordinates &lt;i&gt;x&lt;/i&gt;, &lt;i&gt;y&lt;/i&gt;. In addition, simultaneously with AFM images, images of current for selected areas of the sample surface have been measured. The processes of the Au NPs formation in SiO&lt;sub&gt;2&lt;/sub&gt;–TiO&lt;sub&gt;2&lt;/sub&gt; gel films containing Au(III) ions deposited on glass substrates with an ITO sublayer by the sol–gel method, have been studied in the course of local electrochemical reduction of Au(III) ions using a conducting AFM probe. It is shown that, after the modification of gel films by applying positive voltage pulses to the AFM probe relative to the ITO sublayer, the images of current for the modified regions show channels of current associated with the formation of Au NPs at the interface between the ITO sublayer and of the gel film as a result of local electrochemical reduction of Au(III) in the area under the contact of the AFM probe to the surface of the gel film. It has been established that the formation of Au NPs also manifests itself in the appearance of hysteresis in the cyclic CVC of the contact between the AFM probe and the surface of the gel film measured during the formation of NPs. It was found that, upon modification of the SiO&lt;sub&gt;2&lt;/sub&gt;–TiO&lt;sub&gt;2&lt;/sub&gt; gel film by applying a negative voltage pulse to the AFM probe relative to the ITO sublayer, the formation of toroidal Au nanostructures has been observed, associated with the electrochemical reduction","PeriodicalId":783,"journal":{"name":"Technical Physics","volume":"68 4","pages":"102 - 106"},"PeriodicalIF":0.7,"publicationDate":"2023-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42790090","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":"Stability of Solutions to Systems of Parabolic Equations with Delay","authors":"I. V. Boykov","doi":"10.1134/S1063784223020019","DOIUrl":"10.1134/S1063784223020019","url":null,"abstract":"<p> This work is devoted to analysis of stability (in the Lyapunov sense) of solutions to systems of linear parabolic equations with coefficients depending on time and with delay depending on time. The cases of continuous and impulsive perturbations are considered. A method for studying the stability of solutions to systems of linear parabolic equations is as follows. Applying the Fourier transform to the original system of parabolic equations, we arrive at a system of nonstationary ordinary differential equations with delay depending on time, which is defined in the spectral region. First, the stability of the resulting system is studied by the method of frozen coefficients in the metric of space <i>R</i>_<i>n</i> of n-dimensional vectors. Then the resulting statements are extended to space <i>L</i>₂. The application of the Parseval equality allows us to return to the domain of the originals and to obtain sufficient conditions for the stability of solutions to systems of linear parabolic equations. An algorithm is proposed that allows one to obtain sufficient stability conditions for solutions of finite systems of linear parabolic equations with time-dependent coefficients and with time-dependent delays. Sufficient stability conditions are expressed in terms of the logarithmic norms of matrices composed of the coefficients of the system of parabolic equations. The algorithms are obtained in the metric of space <i>L</i>₂. Algorithms for constructing sufficient stability conditions are efficient both in the case continuous and in the case of impulsive perturbations. A method is proposed for constructing sufficient stability conditions for solutions to finite systems of linear parabolic equations with time-dependent coefficients and delays. The method can be used in the study of nonstationary dynamical systems described by systems of linear parabolic equations with delays depending from time.</p>","PeriodicalId":783,"journal":{"name":"Technical Physics","volume":"68 3","pages":"59 - 66"},"PeriodicalIF":0.7,"publicationDate":"2023-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44488463","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 Effects of 2D Dissipative Tunneling for the Recombination Radiation Spectra of Interacting Quantum Dots in an External Electric Field","authors":"V. D. Krevchik,&nbsp;A. V. Razumov,&nbsp;M. B. Semenov","doi":"10.1134/S1063784223020056","DOIUrl":"10.1134/S1063784223020056","url":null,"abstract":"&lt;p&gt;Quantum dots (QDs) have unique optical properties that are widely used in optoelectronics, biology, and medicine. The problem of controlling the spectral and luminescent properties of QDs has initiated studies of the mechanisms by which QDs interact with each other and with the surrounding matrix. Such interactions can, under certain conditions, significantly modify the radiative properties of QDs, which will affect the characteristics of laser structures and biosensors based on them. The aim of this work is a theoretical study of the 2D dissipative tunneling effect in the “QD–surrounding matrix” system, as well as the pair electrostatic interaction of QDs with &lt;i&gt;A&lt;/i&gt;&lt;sup&gt;&lt;i&gt;+&lt;/i&gt;&lt;/sup&gt; &lt;i&gt;+  e&lt;/i&gt; impurity complexes, on recombination radiation associated with the optical transition of an electron from the QD ground state to the quasi-stationary &lt;i&gt;A&lt;/i&gt;&lt;sup&gt;&lt;i&gt;+&lt;/i&gt;&lt;/sup&gt; state in an external electric field. The interaction of an electron, which is in the ground state of a QD, and a hole that is localized at the &lt;i&gt;A&lt;/i&gt;&lt;sup&gt;&lt;i&gt;+&lt;/i&gt;&lt;/sup&gt; center has been considered within the framework of the adiabatic approximation. The dispersion equations that determine dependence of the hole binding energy in the &lt;i&gt;A&lt;/i&gt;&lt;sup&gt;&lt;i&gt;+&lt;/i&gt;&lt;/sup&gt; &lt;i&gt;+ e&lt;/i&gt; impurity complex in a spherically symmetric QD on the external electric field and dissipative tunneling parameters have been obtained within the zero range potential model, in the effective mass approximation. Calculation of the spectral intensity of recombination radiation (SIRR) in QDs with an &lt;i&gt;A&lt;/i&gt;&lt;sup&gt;&lt;i&gt;+&lt;/i&gt;&lt;/sup&gt;&lt;i&gt;+e&lt;/i&gt; impurity complex in an external electric field has been performed in the dipole approximation. Influence of the electric field on the ground state of an electron in a QD has been taken into account in the second order of the perturbation theory. Numerical calculations and plotting were carried out for a semiconductor quantum dot based on InSb using the symbolic mathematics of Mathcad 14 and Wolfram Mathematica 9. The 2D dissipative tunneling probability has been calculated with exponential accuracy for the 2D oscillatory potential model at a finite temperature, taking into account the linear interaction with the phonon modes of the environment media (or a heat bath) in the one-instanton semiclassical approximation. It is shown that the field dependence of the binding energy for the quasi-stationary &lt;i&gt;A&lt;/i&gt;&lt;sup&gt;&lt;i&gt;+&lt;/i&gt;&lt;/sup&gt; state has an oscillating character, associated with quantum beats that occur during parallel 2D tunneling transfer. It is found that the SIRR curves have a characteristic kink corresponding to the 2D bifurcation point that occurs when the tunneling regimes in the interacting pair of QDs change from synchronous to asynchronous. It has been established that, in the vicinity of the 2D bifurcation point, there are irregular oscillations in the SIRR associated with the modes of quantum beats, in the course of which competing trajectories of tunneling appear. It","PeriodicalId":783,"journal":{"name":"Technical Physics","volume":"68 4","pages":"93 - 101"},"PeriodicalIF":0.7,"publicationDate":"2023-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42947338","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":"Photoinduced Modulation of the Dielectric Permittivity in a System of Interacting Quantum Dots in an External Electric Field","authors":"V. D. Krevchik,&nbsp;A. V. Razumov,&nbsp;M. B. Semenov","doi":"10.1134/S1063784223020044","DOIUrl":"10.1134/S1063784223020044","url":null,"abstract":"<p>At present, much attention is paid to the dielectric engineering of the material of the surrounding matrix and low-dimensional structures, which makes it possible to purposefully change their properties and optimize the characteristics of semiconductor devices. The aim of this work is a theoretical study of the influence of the pair interaction of quantum dots (QDs), as well as their interaction with the surrounding matrix through 2D dissipative tunneling, on the photodielectric effect (PDE) associated with the excitation of an impurity complex <i>A</i>⁺ + <i>e</i> in a QD system in an external electric field. Interaction of an electron with a hole in an impurity complex <i>A</i>⁺ + <i>e</i> in a QD has been considered in the adiabatic approximation. The dispersion equations for a hole in an impurity complex <i>A</i>⁺ + <i>e</i> in the presence of an external electric field and 2D dissipative tunneling for the <i>s</i>- and <i>p</i>-states of an electron in a QD are obtained within the framework of the zero-range potential model in the effective mass approximation. The influence of the electric field on the ground state of an electron in a QD has been taken into account in the second order of the perturbation theory. The probability of 2D dissipative tunneling is calculated in the one-instanton semiclassical approximation. The relative change in dielectric permittivity has been calculated in the dipole approximation. PDE field-dependence curves have been plotted for InSb QDs. It is shown that the PDE field dependence at a certain value of the strength of an external electric field and the parameters of 2D dissipative tunneling has a characteristic kink associated with the effect of 2D bifurcation, when, under the action of an electric field, the double-well oscillatory potential simulating the “QD–surrounding matrix” system is transformed and the tunnel transfer mode changes from synchronous to asynchronous. It has been established that there are irregular oscillations on the PDE curves in the vicinity of the 2D bifurcation point, which are associated with the regime of quantum beats. It is shown that the amplitude of the oscillations increases with increasing phonon mode frequency and temperature, while the break point shifts towards weaker fields. It has been found that an increase in the constant of interaction with the contact medium, as well as with the constant of the pair interaction of QDs, leads to the suppression of the PDE.</p>","PeriodicalId":783,"journal":{"name":"Technical Physics","volume":"68 4","pages":"81 - 92"},"PeriodicalIF":0.7,"publicationDate":"2023-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42129133","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":"Effect of Temperature on Dissipative Electron Tunneling through Co Nanoparticles in HfO2 Films","authors":"V. D. Krevchik,&nbsp;M. B. Semenov,&nbsp;D. O. Filatov,&nbsp;D. A. Antonov","doi":"10.1134/S1063784223020032","DOIUrl":"10.1134/S1063784223020032","url":null,"abstract":"<p>The influence of temperature on the processes of dissipative electron tunneling through individual Co nanoparticles (NPs) in an HfO₂ film (10 nm thick) on a conductive substrate with a Co sublayer has been experimentally studied by atomic force microscopy (AFM) with a conducting probe. Co NPs were formed by local anodic oxidation of the Co sublayer using an AFM probe with subsequent drift of Co ions to the AFM probe, their reduction, and growth of Co NPs near the contact of the AFM probe tip with the HfO₂ film surface. In the experiment, the tunnel current–voltage characteristics (CVC) of the formed Co NPs were measured when voltage was applied between the AFM probe and the Co sublayer at different temperatures in the range of 20–105°С. The experimental results were interpreted on the basis of the theory of one-dimensional dissipative tunneling for a model double-well oscillatory potential in an external electric field. At one of the voltage polarities on the AFM probe, kinks in <i>I–V</i> characteristics were observed, accompanied by current oscillations through the AFM probe <i>I</i>, which, according to the theory, corresponds to the situation when the initially asymmetric double-well potential becomes symmetrical. The amplitude of the mentioned oscillations Δ<i>I</i> falls slightly non-linearly with increasing temperature. The results of the experiment were compared with the results of calculations of the temperature dependence of the maximum amplitude of oscillations on the field dependence of the probability of 1D dissipative tunneling. The obtained qualitative agreement between the experimental 19 and theoretical temperature dependences indicates that the experimentally observed features of <i>I–V</i> characteristics are associated with the effect of macroscopic quantum tunneling with dissipation. A qualitative agreement was obtained between the experimental and theoretical results that allow us to assume the possibility of experimental observation of the macroscopic dissipative tunneling effects [1] and thereby confirm the hypothesis expressed in the groundbreaking works of A.J. Leggett, A.I. Larkin, Yu.N. Ovchinnikov, and other authors.</p>","PeriodicalId":783,"journal":{"name":"Technical Physics","volume":"68 4","pages":"75 - 80"},"PeriodicalIF":0.7,"publicationDate":"2023-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47996280","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":"Partial Areas Method in the Problem of Diffraction of an Electromagnetic Wave by a Longitudinal Partition in an Infinite Waveguide","authors":"G. V. Abgaryan,&nbsp;A. N. Khaibullin,&nbsp;A. E. Shipilo","doi":"10.1134/S1063784223010012","DOIUrl":"10.1134/S1063784223010012","url":null,"abstract":"<p>In this study, we investigate the 2D problem of diffraction of a TE-polarized electromagnetic wave in an infinite waveguide with a longitudinal partition. The mathematical formulation of this physical problem is equivalent to the boundary value problem for the Helmholtz equation with the Dirichlet-type boundary conditions and the joining conditions. The problem is solved by the partial areas method (PAM). In this method, the solution to the problem in each subdomain is sought in the form of a series with unknown coefficients, which are determined from the joining condition at the interface between the media. Using the method of integro-summatory identities, this boundary value problem is reduced to an infinite system of linear algebraic equations (ISLAE) in unknown coefficients. We have derived ISLAE corresponding to the 2D problem of diffraction in an infinite waveguide with a longitudinal diaphragm. Computer experiments have been performed. We have detected resonance effects observed when the frequency of an incident wave is close to the natural frequencies of the subdomains corresponding to the branched part of the waveguide. We have constructed the diagrams of electromagnetic fields at resonance frequencies. The electromagnetic field energies have been calculated for various wavenumbers. Proceeding from the results of computer experiments, it can be concluded that the accuracy of fulfillment of the boundary joining condition depends on the ISLAE truncation parameter. To verify the accuracy of the fulfillment of the boundary conditions, we have introduced the concept of joining mismatch. It is shown that for the incident wave frequencies close to the eigenvalues of subdomains corresponding to the branched part of the waveguide, resonance phenomena are observed.</p>","PeriodicalId":783,"journal":{"name":"Technical Physics","volume":"68 1","pages":"1 - 7"},"PeriodicalIF":0.7,"publicationDate":"2023-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4732233","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":"Predicative Computing Structures and Hybrid Automates in Modeling Invasive Processes and Epidemic COVID Waves","authors":"A. Yu. Perevaryukha","doi":"10.1134/S1063784223010048","DOIUrl":"10.1134/S1063784223010048","url":null,"abstract":"<p>Rapid processes in the area of cell biophysics, invasions, or epidemiology are distinguished by the variety of their variants; therefore, they require original methods of mathematical description for long-term prediction of the state of biophysical systems. Without building predictions of the dynamics of biophysical interaction, it is impossible to improve the technology of industrial exploitation of natural objects. Classical models based on systems of differential equations do not describe the dynamics of real processes that are observed during aggressive invasions of alien species. Known models of “predator/prey” systems assumed the cyclical dynamics of two rival species, but in reality, the oscillatory solution of the model’s equations is only a mathematical hypothesis. In real biosystems, the variants for the development of scenarios after the introduction of an aggressive predator or parasite are more complicated. Dynamics during invasions becomes extreme. In laboratory experiments with ciliates, instead of asynchronous oscillations with the prey, the infused predator after a rapid outbreak completely destroyed the entire population of prey. Processes with abrupt metamorphoses are extremely relevant, for example, the development of an immune response during the presentation of antigens of new strains of coronavirus and the activation of specific T-lymphocytes of immune memory killer cells to destroy infected cells. Modeling of extreme development in our works is based on the aspects of eventfulness and variability of choice during abrupt changes in the stages of the process under study, for example, adaptation of a parasite against a breeding invader, which is an important way to combat invasions. For rapidly changing biophysical processes, we proposed to expand the models in differential equations with the components of eventfulness, delay, trigger switching, and the logic of switching stages of development. Previously, we proposed an original formalization of the event hierarchy for continuous-discrete time in a hybrid model. In the article, we will present a method for including predicates in the model, i.e., logical functions that allow us to calculate the sequence of changes in the behavior of the invasive process. Our predictive logic approach is important for computational modeling with transformations in dangerous and fast invasive processes and waves of the COVID-19 epidemic based on a comparative analysis of scenarios. Based on the predicative choice of the behavior of a hybrid automaton defined for a set of right-hand sides of systems of differential equations, we also formalize the decision-making logic in scenarios with a controlled impact on biosystems. Post-COVID immunodeficiency is the most complex legacy of the pandemic.</p>","PeriodicalId":783,"journal":{"name":"Technical Physics","volume":"68 1","pages":"8 - 17"},"PeriodicalIF":0.7,"publicationDate":"2023-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4427131","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 Model of Structural Interaction of Biophysical Factors during Invasive and Hydrological Changes in the Biosystem of the Caspian Sea","authors":"A. Yu. Perevaryukha","doi":"10.1134/S106378422301005X","DOIUrl":"10.1134/S106378422301005X","url":null,"abstract":"&lt;p&gt;Prediction of biophysical processes under the conditions of a rapid change in the composition of the interacting components of a biosystem requires flexible approaches and a logical analysis of the direction, time, and level of strength of systemic interactions. It is unrealistic to construct a predictive model based on the methods developed by the author for organizing hybrid computing structures for a key component of a biophysical system (such a link is usually considered the most valuable population for the economy) without a scheme for the mutual influence of factors acting on the biotic environment. Direct interaction of the “predator–prey,” “parasite–host,” or “resource–consumer” equations does not fully describe the dynamics of a real biosystem, especially after invasions of aggressive species. This article is devoted to the application of cognitive formalisms of model structuring of conceptual information about the interaction of natural and anthropogenic factors based on the development of graph theory methods. The purpose of the work is to mathematically formalize how a change in one factor will affect the state of other components of biosystems. The new model allowed us to explore mediated interactions that are not always immediately visible, but are critical. To understand the processes after invasions, we will develop a method for analyzing the distribution of indirect effects in biosystems on directly disconnected components. The results of computational studies are logically followed step by step by a theoretical interpretation of the observed changes in the behavior of the model trajectory. A formal analysis of impulses in a sign digraph in the context of the studied situation of bioresources degradation in the Caspian Sea after a large-scale intervention in the biosystem and due to the penetration of the harmful stenophora &lt;i&gt;Mnemiopsis leidyi&lt;/i&gt; has been carried out. It is shown that the choice of a mathematical approach to the description of the situation is successfully based on the results of the analysis of cycles of influence of ecological interlinkages. Previously unaccounted-for links that led to the low efficiency of attempts to artificially reproduce bioresources were revealed. It was confirmed on the basis of the impulse process in the cognitive graph that the purposeful introduction of alien mollusks from the Black Sea into the Caspian Sea to increase the biomass of bottom fauna was one of the factors in the degradation of valuable biological resources with an increase in the level of the Caspian Sea. Alien mollusks (&lt;i&gt;Abra ovata&lt;/i&gt;, &lt;i&gt;Mytilaster lineatus&lt;/i&gt;) replaced the native benthic fauna. At the end of the 1980s, the salinity of the Northern Caspian decreased; then, the invaders adapted to more saline water drastically reduced the biomass. Competition in the trophic chains of unstable biosystems should not be aggravated in order to increase their productivity for valuable populations. The mass release of","PeriodicalId":783,"journal":{"name":"Technical Physics","volume":"68 2","pages":"35 - 45"},"PeriodicalIF":0.7,"publicationDate":"2023-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4427139","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":"Features of the Formation of Ni–GaAs Contacts Obtained by Electrolysis and Their Electrophysical Properties","authors":"V. V. Filippov,&nbsp;S. E. Luzyanin,&nbsp;K. A. Bogonosov","doi":"10.1134/S1063784223010036","DOIUrl":"10.1134/S1063784223010036","url":null,"abstract":"<p>Nickel contacts based on gallium arsenide are of interest from the point of view of their application in optoelectronics. The aim of this work is to study the contact structures of Ni–p-GaAs and Ni–n-GaAs. The object of study is the electrochemical contacts of nickel to crystalline gallium arsenide. The article presents studies of the topography of homogeneous electrochemical nickel films of nanometer thickness (50–100 nm) on the surface of a semiconductor. The current–voltage characteristics of metal–semiconductor contacts are experimentally obtained. The roughness of the GaAs substrate of the Ni film was studied using optical and probe microscopes. Nickel films were obtained using a Watts solution and a setup for the production of electrochemical structures by the drop method. To minimize the roughness of the nickel surface obtained by electrolysis, a mode of low current density is used. Using a theoretical model and experimental data, the contact resistances are calculated and their current–voltage characteristics are obtained. The parameters of nickel surface roughness, which affect the operational properties of contact structures, are determined. The features of the current flow through the electrochemically obtained Ni–GaAs contacts are revealed. It is shown that the resulting Ni–p-GaAs structures are Ohmic, and the current–voltage characteristics of the Ni–n-GaAs contacts have a nonlinear region at voltages less than 1.5 V. It is shown that the formation of an integral nickel film on the GaAs surface is possible when the Ni layer thickness exceeds the average substrate roughness.</p>","PeriodicalId":783,"journal":{"name":"Technical Physics","volume":"68 2","pages":"27 - 34"},"PeriodicalIF":0.7,"publicationDate":"2023-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4423044","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}