Pub Date : 2021-12-29DOI: 10.26565/2311-0872-2021-35-05
Iana Volvach, O. Dumin, V. Plakhtii, P. Fomin
Background: One of the most promising areas of development of modern electronics is the creation of spintronic devices, which should replace the traditional semiconductor elements. The use of electron spin as a carrier of information in magnetic nanostructures can radically change modern life. Objectives: The aim of this work is to find ways to increase the power of the generator on the magnetic nanostructure by changing its electrical circuit and more optimal external electromagnetic parameters that affect the state of electrons in the studied layered structure. Materials and methods: The solution of this problem is carried out by numerical simulation of the magnetic nanostructure using a specially created micromagnetic simulator, which implements an algorithm for the simultaneous solution of the system of Maxwell and Landau-Lifshitz-Hilbert equations. The solution of such a complex problem is accelerated by the use of a quasi-static approximation in solving the system of Maxwell's equations, which is justified by the small size of the calculation area compared to the depth of the skin layer. Further calculations of the electrodynamic system are performed using the finite element method. To obtain the best frequency and energy parameters of the generator, it is proposed to introduce a resonant circuit to the schematic diagram of the studied generator, which is excited by short nanosecond pulses. Results: A scheme of a generator on a magnetic nanostructure containing a resonator with concentrated parameters is proposed, and a system of nonlinear integro-differential equations with respect to electric currents is obtained in general. Numerical calculation of this system includes, in addition to the calculation of the scheme, also the modeling of a nonlinear electrodynamic structure by the finite element method. The energy and spectral characteristics of the studied generator are obtained. The search for the optimal values of the geometric parameters of the nanostructure and the magnitude of the external longitudinal magnetization is carried out. Conclusions: Due to the complex nature of nonlinear processes in the magnetic nanostructure, the use of an external resonator, which could improve the spectral parameters of the generated current, did not give a noticeable improvement. The influence of the value of the external magnetization on the output power of the generator is complex and nonlinear, but, in general, a decrease in the level of magnetization leads to a significant decrease in power. It is established that the thickness of the magnetic layer of 6 nm is optimal for improving the energy characteristics of the generator.
{"title":"Increasing power of generator on nonlinear magnetic nanostructure","authors":"Iana Volvach, O. Dumin, V. Plakhtii, P. Fomin","doi":"10.26565/2311-0872-2021-35-05","DOIUrl":"https://doi.org/10.26565/2311-0872-2021-35-05","url":null,"abstract":"Background: One of the most promising areas of development of modern electronics is the creation of spintronic devices, which should replace the traditional semiconductor elements. The use of electron spin as a carrier of information in magnetic nanostructures can radically change modern life.\u0000\u0000Objectives: The aim of this work is to find ways to increase the power of the generator on the magnetic nanostructure by changing its electrical circuit and more optimal external electromagnetic parameters that affect the state of electrons in the studied layered structure.\u0000\u0000Materials and methods: The solution of this problem is carried out by numerical simulation of the magnetic nanostructure using a specially created micromagnetic simulator, which implements an algorithm for the simultaneous solution of the system of Maxwell and Landau-Lifshitz-Hilbert equations. The solution of such a complex problem is accelerated by the use of a quasi-static approximation in solving the system of Maxwell's equations, which is justified by the small size of the calculation area compared to the depth of the skin layer. Further calculations of the electrodynamic system are performed using the finite element method. To obtain the best frequency and energy parameters of the generator, it is proposed to introduce a resonant circuit to the schematic diagram of the studied generator, which is excited by short nanosecond pulses.\u0000\u0000Results: A scheme of a generator on a magnetic nanostructure containing a resonator with concentrated parameters is proposed, and a system of nonlinear integro-differential equations with respect to electric currents is obtained in general. Numerical calculation of this system includes, in addition to the calculation of the scheme, also the modeling of a nonlinear electrodynamic structure by the finite element method. The energy and spectral characteristics of the studied generator are obtained. The search for the optimal values of the geometric parameters of the nanostructure and the magnitude of the external longitudinal magnetization is carried out.\u0000\u0000Conclusions: Due to the complex nature of nonlinear processes in the magnetic nanostructure, the use of an external resonator, which could improve the spectral parameters of the generated current, did not give a noticeable improvement. The influence of the value of the external magnetization on the output power of the generator is complex and nonlinear, but, in general, a decrease in the level of magnetization leads to a significant decrease in power. It is established that the thickness of the magnetic layer of 6 nm is optimal for improving the energy characteristics of the generator.","PeriodicalId":91202,"journal":{"name":"Annual book of ASTM standards. Section 11, Water and environmental technology. ASTM Committee E-35 on Pesticides","volume":"2021 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80867512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-29DOI: 10.26565/2311-0872-2021-35-02
V. Khrychov, M. Legenkiy
Relevance: Reducing the radar visibility of an object is an important task in the creation of military equipment. Real objects are often located on some underlying surface, which leads to a significant increasing in the scattered field by such a system in comparison with the scattered field by only object without taking into account re-reflection from the underlying surface. The development of methods for reducing the reflected field plays an important role among the tasks of reducing radar signature. The purpose of the work is to consider the existing methods for modeling the scattering of electromagnetic waves on complex shape objects against the background of the underlying surface, analyze the level of the reflected field components. To propose methods for reducing the radar visibility of an object. To carry out a simulation for some object in order to assess the effectiveness of the proposed methods. Materials and methods: The problem of diffraction on the complex shape object, which located on the underlying surface, is solved. In this case, different components of the scattered field are taken into account: single reflection from different elements of the object's surface (physical-optical component); one-time re-reflections between different parts of the object; re-reflection between the object and the underlying surface. In numerical modeling, the scattered field on an object located on the underlying surface, the underlying surface is considered as a rectangle of finite size. Results: The possibilities of optimizing a model of the complex shape object in order to reduce its radar visibility are considered. In particular, geometric modifications of the object's surface and the using radio-absorbing materials are considered. In order to demonstrate the effect of these techniques, using a technique previously proposed by the authors for determining the scattered field by an object of complex shape located against the background of the underlying surface simulations have been carried out. Conclusion: Methods of optimizing a model of the complex shape object to reduce its radar visibility are proposed. For most real objects, the largest contribution to the total reflected field is made by the field reflected from the smooth part of the object and the re-reflection field between parts of the object and between the object and the underlying surface.
{"title":"About reducing the visibility of complex object on the background of underlying surface","authors":"V. Khrychov, M. Legenkiy","doi":"10.26565/2311-0872-2021-35-02","DOIUrl":"https://doi.org/10.26565/2311-0872-2021-35-02","url":null,"abstract":"Relevance: Reducing the radar visibility of an object is an important task in the creation of military equipment. Real objects are often located on some underlying surface, which leads to a significant increasing in the scattered field by such a system in comparison with the scattered field by only object without taking into account re-reflection from the underlying surface. The development of methods for reducing the reflected field plays an important role among the tasks of reducing radar signature.\u0000\u0000The purpose of the work is to consider the existing methods for modeling the scattering of electromagnetic waves on complex shape objects against the background of the underlying surface, analyze the level of the reflected field components. To propose methods for reducing the radar visibility of an object. To carry out a simulation for some object in order to assess the effectiveness of the proposed methods.\u0000\u0000Materials and methods: The problem of diffraction on the complex shape object, which located on the underlying surface, is solved. In this case, different components of the scattered field are taken into account: single reflection from different elements of the object's surface (physical-optical component); one-time re-reflections between different parts of the object; re-reflection between the object and the underlying surface. In numerical modeling, the scattered field on an object located on the underlying surface, the underlying surface is considered as a rectangle of finite size.\u0000\u0000Results: The possibilities of optimizing a model of the complex shape object in order to reduce its radar visibility are considered. In particular, geometric modifications of the object's surface and the using radio-absorbing materials are considered. In order to demonstrate the effect of these techniques, using a technique previously proposed by the authors for determining the scattered field by an object of complex shape located against the background of the underlying surface simulations have been carried out.\u0000\u0000Conclusion: Methods of optimizing a model of the complex shape object to reduce its radar visibility are proposed. For most real objects, the largest contribution to the total reflected field is made by the field reflected from the smooth part of the object and the re-reflection field between parts of the object and between the object and the underlying surface.","PeriodicalId":91202,"journal":{"name":"Annual book of ASTM standards. Section 11, Water and environmental technology. ASTM Committee E-35 on Pesticides","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91093186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-29DOI: 10.26565/2311-0872-2021-35-08
О. V. Kazanko, О. E. Penkina
Relevance. In recent decades (about the 90-s ХХ century) there has been rapid development of photonic. Thus, to arise scientific interest to optic range of electromagnetic radiation. Currently, the diffraction problem about scattering electromagnetic waves on such object as photonic crystal is impotent problem. As well known, this problem can be reduced to a solution of wave equation. The need to calculate the norm iegnfunction spectral iegnfunction Sturm-Liouville problem, however, to arise in the transition from one complete orthogonal system to another complete orthogonal system of functions by separating variables method, correspondingly, for a wave equation solving. The purpose of the work. We indicate a direct approach to calculating of the norm of iegnfunction of spectral Sturm-Liouville problem for the tow-layer infinite one-dimension photonic crystal (a direct approach to calculating of the norm that is presuppose a direct integration); and propose a methodologically different approach, which is based on the marginal transition in the scalar product, which accordingly sets this norm. Materials and methods. Taking the limit in calculation the norm of the iegnfunction of spectral Sturm-Liouville problem for the tow-layer infinite one-dimension photonic crystal encounters difficulties, associated with the emergence of species uncertainty . Such infinitive investigates by the Lopital's rule. In turn, Lopital's rule entails the need to find a derivative of solution of spectral equation by a spectral param. In this way we have to face the solution a linear inhomogeneous differential equation 2-nd order. Results. We propose a methodic of calculating of norm of iegnfunction of spectral Sturm-Liouville problem for the tow-layer infinite one-dimension photonic crystal. Conclusion. Unlike the direct approach, proposed methodic to make it possible to understand the character of dependencies the required norm of iegnfunction itself (ending expression containing the iegnfunction itself). Further work in this direction of development of this approach may be aimed at simplifying the final expression for the norm.
{"title":"Norm of iegnfunction of one-dimension photonic crystal","authors":"О. V. Kazanko, О. E. Penkina","doi":"10.26565/2311-0872-2021-35-08","DOIUrl":"https://doi.org/10.26565/2311-0872-2021-35-08","url":null,"abstract":"Relevance. In recent decades (about the 90-s ХХ century) there has been rapid development of photonic. Thus, to arise scientific interest to optic range of electromagnetic radiation. Currently, the diffraction problem about scattering electromagnetic waves on such object as photonic crystal is impotent problem. As well known, this problem can be reduced to a solution of wave equation. The need to calculate the norm iegnfunction spectral iegnfunction Sturm-Liouville problem, however, to arise in the transition from one complete orthogonal system to another complete orthogonal system of functions by separating variables method, correspondingly, for a wave equation solving.\u0000\u0000The purpose of the work. We indicate a direct approach to calculating of the norm of iegnfunction of spectral Sturm-Liouville problem for the tow-layer infinite one-dimension photonic crystal (a direct approach to calculating of the norm that is presuppose a direct integration); and propose a methodologically different approach, which is based on the marginal transition in the scalar product, which accordingly sets this norm.\u0000\u0000Materials and methods. Taking the limit in calculation the norm of the iegnfunction of spectral Sturm-Liouville problem for the tow-layer infinite one-dimension photonic crystal encounters difficulties, associated with the emergence of species uncertainty . Such infinitive investigates by the Lopital's rule. In turn, Lopital's rule entails the need to find a derivative of solution of spectral equation by a spectral param. In this way we have to face the solution a linear inhomogeneous differential equation 2-nd order.\u0000\u0000Results. We propose a methodic of calculating of norm of iegnfunction of spectral Sturm-Liouville problem for the tow-layer infinite one-dimension photonic crystal.\u0000\u0000Conclusion. Unlike the direct approach, proposed methodic to make it possible to understand the character of dependencies the required norm of iegnfunction itself (ending expression containing the iegnfunction itself). Further work in this direction of development of this approach may be aimed at simplifying the final expression for the norm.","PeriodicalId":91202,"journal":{"name":"Annual book of ASTM standards. Section 11, Water and environmental technology. ASTM Committee E-35 on Pesticides","volume":"120 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85936522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-29DOI: 10.26565/2311-0872-2021-35-01
V. Bykov, N. Kolchigin, G. Y. Miroshnik, T. V. Miroshnik, О. M. Sotnikov
Relevance. Spline interpolation is used to improve the accuracy of correlation-extreme navigation systems. A two-stage algorithm for combining images in correlation-extreme navigation systems is proposed. At the first stage, the surface of the decision function of the algorithm is constructed in the vicinity of its extremum using a quadratic interpolator by six points and its Gaussian curvature and extremum coordinates are estimated. These parameters are used to determine the optimal value of the parameter of the cubic spline interpolator used in the second stage in order to refine the rough estimate of the coordinates and improve the positioning accuracy of the navigation system. Purpose of the work: The purpose of the work is to develop an algorithm for aligning images in correlation-extreme navigation systems, which makes it possible to realize a cubic spline parameter close to the optimal value for each of the possible shifts of the current image relative to the reference image and, as a result, to increase the accuracy of determining the coordinates. Materials and methods. In correlation-extreme navigation systems, the coordinates of the aircraft are determined by calculating the mutual shift of the current image obtained using the sensor of the Earth's physical field and the reference image, which is known in advance. At the same time, the alignment accuracy of discrete current and reference images, which are usually used in practice, does not exceed half a pixel. Therefore, the problem of improving the accuracy of navigation systems is of great importance. One of the possible ways to solve this problem is to use methods for approximating the decision function of the image alignment algorithm in the vicinity of its global maximum.Results: To illustrate the gain in the accuracy of the positioning of navigation systems, statistical tests of the algorithm with a 6-point interpolator and the above-described two-stage procedure for minimizing the decision function containing spline interpolation at the second stage were carried out. A typical image was used as a reference image. The coordinates of the center of the current and reference images were played randomly in accordance with the two-dimensional normal distribution law, the average value of which coincided with the center of the reference image; the standard deviation is also found. Then the current image was formed. The constructed current image was noisy with additive white Gaussian noise with zero mean value and the same standard deviation for each element . Image alignment was assumed to be correct if the following conditions were met: , where – is the shift estimate generated by the algorithm. Then, the algorithms were repeatedly run with different realizations of the noise component of the current image, and the dependences of the root-mean-square error in each direction on the mean-square value were plotted . The figures in the article show the dependencies for the algorithm with
{"title":"Applying spline interpolation to increase accuracy of correlation-emergency navigation systems","authors":"V. Bykov, N. Kolchigin, G. Y. Miroshnik, T. V. Miroshnik, О. M. Sotnikov","doi":"10.26565/2311-0872-2021-35-01","DOIUrl":"https://doi.org/10.26565/2311-0872-2021-35-01","url":null,"abstract":"Relevance. Spline interpolation is used to improve the accuracy of correlation-extreme navigation systems. A two-stage algorithm for combining images in correlation-extreme navigation systems is proposed. At the first stage, the surface of the decision function of the algorithm is constructed in the vicinity of its extremum using a quadratic interpolator by six points and its Gaussian curvature and extremum coordinates are estimated. These parameters are used to determine the optimal value of the parameter of the cubic spline interpolator used in the second stage in order to refine the rough estimate of the coordinates and improve the positioning accuracy of the navigation system.\u0000\u0000Purpose of the work: The purpose of the work is to develop an algorithm for aligning images in correlation-extreme navigation systems, which makes it possible to realize a cubic spline parameter close to the optimal value for each of the possible shifts of the current image relative to the reference image and, as a result, to increase the accuracy of determining the coordinates.\u0000\u0000Materials and methods. In correlation-extreme navigation systems, the coordinates of the aircraft are determined by calculating the mutual shift of the current image obtained using the sensor of the Earth's physical field and the reference image, which is known in advance. At the same time, the alignment accuracy of discrete current and reference images, which are usually used in practice, does not exceed half a pixel. Therefore, the problem of improving the accuracy of navigation systems is of great importance. One of the possible ways to solve this problem is to use methods for approximating the decision function of the image alignment algorithm in the vicinity of its global maximum.Results: To illustrate the gain in the accuracy of the positioning of navigation systems, statistical tests of the algorithm with a 6-point interpolator and the above-described two-stage procedure for minimizing the decision function containing spline interpolation at the second stage were carried out. A typical image was used as a reference image. The coordinates of the center of the current and reference images were played randomly in accordance with the two-dimensional normal distribution law, the average value of which coincided with the center of the reference image; the standard deviation is also found. Then the current image was formed. The constructed current image was noisy with additive white Gaussian noise with zero mean value and the same standard deviation for each element . Image alignment was assumed to be correct if the following conditions were met: , where – is the shift estimate generated by the algorithm. Then, the algorithms were repeatedly run with different realizations of the noise component of the current image, and the dependences of the root-mean-square error in each direction on the mean-square value were plotted . The figures in the article show the dependencies for the algorithm with","PeriodicalId":91202,"journal":{"name":"Annual book of ASTM standards. Section 11, Water and environmental technology. ASTM Committee E-35 on Pesticides","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88924658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-29DOI: 10.26565/2311-0872-2021-35-07
G. Katrich, S. Petrushenko, O. Botsula
Background. Zinc oxide (ZnO) is a promising material for designing the semiconductor radiation sources and detectors in the region of short wavelengths of the optical range. Films based on ZnO are considered as possible elements of optoelectronic devices that can be used to influence their optical properties. Nowadays, the methods of making such films are quite diverse, however, obtaining high-quality and inexpensive ZnO films remains an actual scientific and engineering task that needs to be solved. Thus, the research in this direction and the development of recommendations on the synthesis of ZnO films is urgent. Purpose of Work. The aim of the work is to obtain ZnO films by the sol-gel technique, to evaluate their structure and optical properties and to estimate the affect of ultraviolet radiation on the structure and optical characteristics of the obtained films. Techniques and Methodology. The process of obtaining ZnO films is considered. The process of obtaining such films by sol-gel technique is described. A visual analysis of the experimentally obtained films has been carried out. The optical properties of ZnO films were experimentally examined. In particular, the influence of ultraviolet radiation used at the stage of obtaining films on the features of their ability to absorb radiation in the optical range is analyzed. Results. ZnO films were grown experimentally by sol-gel technique. ZnO films were formed on quartz substrates. The formation of ZnO nanoparticles is observed in the films obtained without the influence of radiation. The usage of ultraviolet radiation at the stage of the final heat treatment at a temperature of 480 °C leads to the formation of a higher quality ZnO film and a decrease in the size of the granules. Analysis of the chemical composition of the films using X-ray fluorescence analysis shows the presence of zinc and oxygen in the formed films, as well as insignificant carbon content, which is associated with the use of quartz as substrates. The dependencies of the transmission capacity of ZnO films on the wavelength of radiation incident on the film in the range of 200-450 nm are obtained. It is shown that in films exposed to ultraviolet radiation at the stage of heat treatment, there is a shift in the value of the cut-off wavelength corresponding to the absorption edge and, accordingly, a decrease in the band gap calculated from the results of the experiment. Conclusions: To summarize the results of the research we can highlight that the influence of ultraviolet radiation at the stage of the final heat treatment on ZnO films formed by sol-gel method leads to an improvement in the quality of the films and to a change in their optical properties, in particular, a decrease in the energy corresponding to the absorption threshold.
{"title":"Optic properties of ZnO films grown by sol-gel technique","authors":"G. Katrich, S. Petrushenko, O. Botsula","doi":"10.26565/2311-0872-2021-35-07","DOIUrl":"https://doi.org/10.26565/2311-0872-2021-35-07","url":null,"abstract":"Background. Zinc oxide (ZnO) is a promising material for designing the semiconductor radiation sources and detectors in the region of short wavelengths of the optical range. Films based on ZnO are considered as possible elements of optoelectronic devices that can be used to influence their optical properties. Nowadays, the methods of making such films are quite diverse, however, obtaining high-quality and inexpensive ZnO films remains an actual scientific and engineering task that needs to be solved. Thus, the research in this direction and the development of recommendations on the synthesis of ZnO films is urgent.\u0000\u0000Purpose of Work. The aim of the work is to obtain ZnO films by the sol-gel technique, to evaluate their structure and optical properties and to estimate the affect of ultraviolet radiation on the structure and optical characteristics of the obtained films.\u0000\u0000Techniques and Methodology. The process of obtaining ZnO films is considered. The process of obtaining such films by sol-gel technique is described. A visual analysis of the experimentally obtained films has been carried out. The optical properties of ZnO films were experimentally examined. In particular, the influence of ultraviolet radiation used at the stage of obtaining films on the features of their ability to absorb radiation in the optical range is analyzed.\u0000\u0000Results. ZnO films were grown experimentally by sol-gel technique. ZnO films were formed on quartz substrates. The formation of ZnO nanoparticles is observed in the films obtained without the influence of radiation. The usage of ultraviolet radiation at the stage of the final heat treatment at a temperature of 480 °C leads to the formation of a higher quality ZnO film and a decrease in the size of the granules. Analysis of the chemical composition of the films using X-ray fluorescence analysis shows the presence of zinc and oxygen in the formed films, as well as insignificant carbon content, which is associated with the use of quartz as substrates. The dependencies of the transmission capacity of ZnO films on the wavelength of radiation incident on the film in the range of 200-450 nm are obtained. It is shown that in films exposed to ultraviolet radiation at the stage of heat treatment, there is a shift in the value of the cut-off wavelength corresponding to the absorption edge and, accordingly, a decrease in the band gap calculated from the results of the experiment.\u0000\u0000Conclusions: To summarize the results of the research we can highlight that the influence of ultraviolet radiation at the stage of the final heat treatment on ZnO films formed by sol-gel method leads to an improvement in the quality of the films and to a change in their optical properties, in particular, a decrease in the energy corresponding to the absorption threshold.","PeriodicalId":91202,"journal":{"name":"Annual book of ASTM standards. Section 11, Water and environmental technology. ASTM Committee E-35 on Pesticides","volume":"55 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78618896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-29DOI: 10.26565/2311-0872-2021-35-06
L. Chernogor, L. I. Mylovanova, Y. Mylovanov, A. M. Tsymbal, Y. Luo
Background. Ionospheric effects from solar eclipses (SEs) have been studied for over a century. The studies intensified in the 1960–1970, when rockets, satellites, ionosonde networks, and incoherent scatter radars became actively involved in the investigations. The following basic features of SEs displayed in the ionosphere have been established: a decrease in the electron density and the electron, ion, and neutral temperatures, changes in the dynamics of the ionosphere, and the generation of acoustic and atmospheric gravity waves. The recurring regular features are observed together with the features pertaining to each individual SE. Therefore, the study of the effects of each new solar eclipse is an urgent task. The purpose of this paper is to present the results of analysis of the ionogram measurements acquired by the digisonde located at the Radiophysical Observatory, V. N. Karazin Kharkiv National University. Techniques and Methodology. The observations of the state of the ionosphere were made using the digisonde specifically developed by the V. N. Karazin Kharkiv National University and located at the V. N. Karazin Kharkiv National University Radiophysical Observatory (49°38' N, 36°20' E). The data processing included the following. First, the time series of critical F2-layer frequencies, foF2, of the minimum frequency, fmin, observed on an ionogram, and of the virtual height were plotted. Second, the trends and the differences between the initial series and the trends were calculated. Third, given the foF2(t) values, the electron densities N(t) and their increments ΔN(t) were calculated, and fourth, the systems spectral analysis of ΔN(t) dependences was conducted to determine the spectral content. Results. A maximum decrease of 3.7–3.8% in the F2 peak electron density has been detected. This value agrees very well with the calculated value of 3.5–3.8%. The time delay between the minimum in the electron density observed and the maximum value of the phase of the solar eclipse was determined to be 12.5 min, which is in good agreement with the calculated value of 12.8 min. The time delay suggests that the linear loss coefficient was 1.3´10–3 s–1 and the production rate was (3.8–3.9)×108 m–3∙s–1. The SE was associated with the generation of quasi-periodic oscillations in the electron density and the F2 layer virtual height, within the period range of 10–15 min, and with amplitudes of 1.7–4% and 9.1–11.4%, respectively. The fluctuations in the minimum frequency observed on the ionograms showed a factor of 3–4 times decrease in the course of the SE. In addition, a decrease in the averaged values was observed to occur from 3 to 2.85 MHz (by 5%), which suggested that the radio wave attenuation by absorption decreased due to a decrease in the lower-ionosphere electron density below 100 km altitude. This decrease was estimated to be about 2%, while the decrease determined from the observations gave 2.2%. Conclusions. The partial solar eclipse wit
背景。日食(SEs)对电离层的影响已经研究了一个多世纪。这些研究在1960-1970年得到加强，当时火箭、卫星、电离层探空网和非相干散射雷达都积极参与了调查。建立了电离层se的基本特征:电子密度和电子、离子、中性温度下降，电离层动力学变化，声波和大气重力波的产生。将重复出现的规则特征与与每个SE相关的特征一起观察。因此，研究每一次新日食的影响是一项紧迫的任务。本文的目的是介绍由哈尔科夫国立大学V. N. Karazin国立大学放射物理观测站的激光探测仪获得的离子图分析结果。技术和方法论。使用V. N. Karazin Kharkiv国立大学专门开发的位于V. N. Karazin Kharkiv国立大学放射物理观测站(49°38' N, 36°20' E)的digisonde对电离层状态进行了观测。数据处理包括以下内容。首先，绘制了电离图上观测到的最小频率fmin和虚拟高度的临界f2层频率foF2的时间序列。其次，计算了初始序列与趋势的变化趋势及差异。第三，给定foF2(t)值，计算电子密度N(t)及其增量ΔN(t);第四，进行系统光谱分析ΔN(t)依赖关系，确定光谱含量。F2峰电子密度最大下降3.7 ~ 3.8%。该值与计算值3.5-3.8%非常吻合。观测到的电子密度最小值与日全食相位最大值之间的时间延迟为12.5 min，与计算值12.8 min吻合较好。该时间延迟表明线损耗系数为1.3´10-3 s-1，产率为(3.8-3.9)×108 m-3∙s-1。SE与电子密度和F2层虚高产生准周期振荡有关，周期范围为10 ~ 15 min，振幅分别为1.7 ~ 4%和9.1 ~ 11.4%。在电离图上观察到的最小频率的波动表明，在东南偏南过程中下降了3-4倍。此外，观测到从3到2.85 MHz的平均值下降了5%，这表明由于100 km高度以下电离层电子密度的降低，无线电波的吸收衰减减少了。这一下降估计约为2%，而根据观察确定的下降为2.2%。最大星等极小值(0.112)的日偏食和4.4%的遮蔽作用对电离层产生了一定的影响。
{"title":"Effects from the June 10, 2021 solar eclipse in the ionosphere over Kharkiv: results from ionosonde measurements","authors":"L. Chernogor, L. I. Mylovanova, Y. Mylovanov, A. M. Tsymbal, Y. Luo","doi":"10.26565/2311-0872-2021-35-06","DOIUrl":"https://doi.org/10.26565/2311-0872-2021-35-06","url":null,"abstract":"Background. Ionospheric effects from solar eclipses (SEs) have been studied for over a century. The studies intensified in the 1960–1970, when rockets, satellites, ionosonde networks, and incoherent scatter radars became actively involved in the investigations. The following basic features of SEs displayed in the ionosphere have been established: a decrease in the electron density and the electron, ion, and neutral temperatures, changes in the dynamics of the ionosphere, and the generation of acoustic and atmospheric gravity waves. The recurring regular features are observed together with the features pertaining to each individual SE. Therefore, the study of the effects of each new solar eclipse is an urgent task.\u0000\u0000The purpose of this paper is to present the results of analysis of the ionogram measurements acquired by the digisonde located at the Radiophysical Observatory, V. N. Karazin Kharkiv National University.\u0000\u0000Techniques and Methodology. The observations of the state of the ionosphere were made using the digisonde specifically developed by the V. N. Karazin Kharkiv National University and located at the V. N. Karazin Kharkiv National University Radiophysical Observatory (49°38' N, 36°20' E). The data processing included the following. First, the time series of critical F2-layer frequencies, foF2, of the minimum frequency, fmin, observed on an ionogram, and of the virtual height were plotted. Second, the trends and the differences between the initial series and the trends were calculated. Third, given the foF2(t) values, the electron densities N(t) and their increments ΔN(t) were calculated, and fourth, the systems spectral analysis of ΔN(t) dependences was conducted to determine the spectral content.\u0000\u0000Results. A maximum decrease of 3.7–3.8% in the F2 peak electron density has been detected. This value agrees very well with the calculated value of 3.5–3.8%. The time delay between the minimum in the electron density observed and the maximum value of the phase of the solar eclipse was determined to be 12.5 min, which is in good agreement with the calculated value of 12.8 min. The time delay suggests that the linear loss coefficient was 1.3´10–3 s–1 and the production rate was (3.8–3.9)×108 m–3∙s–1. The SE was associated with the generation of quasi-periodic oscillations in the electron density and the F2 layer virtual height, within the period range of 10–15 min, and with amplitudes of 1.7–4% and 9.1–11.4%, respectively. The fluctuations in the minimum frequency observed on the ionograms showed a factor of 3–4 times decrease in the course of the SE. In addition, a decrease in the averaged values was observed to occur from 3 to 2.85 MHz (by 5%), which suggested that the radio wave attenuation by absorption decreased due to a decrease in the lower-ionosphere electron density below 100 km altitude. This decrease was estimated to be about 2%, while the decrease determined from the observations gave 2.2%.\u0000\u0000Conclusions. The partial solar eclipse wit","PeriodicalId":91202,"journal":{"name":"Annual book of ASTM standards. Section 11, Water and environmental technology. ASTM Committee E-35 on Pesticides","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87551672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-29DOI: 10.26565/2311-0872-2021-35-03
D. Batrakov, М. Kovalov, А.О. Maslennikov, А.G. Batrakova, S. Urdzik
Relevance. The relevance of the studies outlined in the article is due to their focus on the implementation of the state strategy for ensuring the reliability and extending the resource of transport and engineering structures, the implementation of which is associated with the methods and means of obtaining information and processing it in real time; methods for assessing the state of engineering structures, a feature of which is a significant heterogeneity of geometric and physical-mechanical parameters, which complicates the use of diagnostic results. With the obvious advantages of wave sounding methods, their application is constrained by the complexity of the tasks of interpreting the results obtained and the associated errors in determining the parameters of structures; the multifactorial nature of the problems of evaluating the parameters of multicomponent materials of structures, the imperfection of flaw detection methods. Purpose of work – a review of the capabilities of modern georadars and means of processing ultra-wideband signals together with computer-oriented systems for numerical modeling, optimization of methods for processing georadar data for solving problems of detecting and identifying subsurface irregularities in building structures that are a flat-layered medium. Materials and methods. The first part of the article provides a brief overview of the main methods of processing data sets obtained using pulsed GPR. A new method of data processing using specialized software is proposed GeoVizy. The possibilities of using the methods of the modern theory of diffraction and methods of signal analysis in the space-time domain for solving the problems of flaw detection are also briefly considered. Results. The results obtained in this work are based on remote sensing data, proposed mathematical models and methods for processing sensing data. Based on the results of the comparative analysis of the capabilities of georadars, practical recommendations were proposed to improve the reliability of the data sets obtained, and possible directions for further research were substantiated. Conclusions. The results of numerical modeling and laboratory experiments obtained in this work confirmed the previously stated theoretical assumptions about the degree of influence of the key parameters of ultra-wideband GPR on the reliability of the results obtained. The significance of the new scientific results obtained consists not only in the use of new sensing means and new models of processing and subsequent interpretation of the data obtained, but also in the considered prospects for progress in the field of non-destructive testing and diagnostics.
{"title":"Non-destructive control of roads by georadars (review article, part I)","authors":"D. Batrakov, М. Kovalov, А.О. Maslennikov, А.G. Batrakova, S. Urdzik","doi":"10.26565/2311-0872-2021-35-03","DOIUrl":"https://doi.org/10.26565/2311-0872-2021-35-03","url":null,"abstract":"Relevance. The relevance of the studies outlined in the article is due to their focus on the implementation of the state strategy for ensuring the reliability and extending the resource of transport and engineering structures, the implementation of which is associated with the methods and means of obtaining information and processing it in real time; methods for assessing the state of engineering structures, a feature of which is a significant heterogeneity of geometric and physical-mechanical parameters, which complicates the use of diagnostic results. With the obvious advantages of wave sounding methods, their application is constrained by the complexity of the tasks of interpreting the results obtained and the associated errors in determining the parameters of structures; the multifactorial nature of the problems of evaluating the parameters of multicomponent materials of structures, the imperfection of flaw detection methods.\u0000\u0000Purpose of work – a review of the capabilities of modern georadars and means of processing ultra-wideband signals together with computer-oriented systems for numerical modeling, optimization of methods for processing georadar data for solving problems of detecting and identifying subsurface irregularities in building structures that are a flat-layered medium.\u0000\u0000Materials and methods. The first part of the article provides a brief overview of the main methods of processing data sets obtained using pulsed GPR. A new method of data processing using specialized software is proposed GeoVizy. The possibilities of using the methods of the modern theory of diffraction and methods of signal analysis in the space-time domain for solving the problems of flaw detection are also briefly considered. \u0000\u0000Results. The results obtained in this work are based on remote sensing data, proposed mathematical models and methods for processing sensing data. Based on the results of the comparative analysis of the capabilities of georadars, practical recommendations were proposed to improve the reliability of the data sets obtained, and possible directions for further research were substantiated.\u0000\u0000Conclusions. The results of numerical modeling and laboratory experiments obtained in this work confirmed the previously stated theoretical assumptions about the degree of influence of the key parameters of ultra-wideband GPR on the reliability of the results obtained. The significance of the new scientific results obtained consists not only in the use of new sensing means and new models of processing and subsequent interpretation of the data obtained, but also in the considered prospects for progress in the field of non-destructive testing and diagnostics.","PeriodicalId":91202,"journal":{"name":"Annual book of ASTM standards. Section 11, Water and environmental technology. ASTM Committee E-35 on Pesticides","volume":"166 1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83327009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The American Conference of Governmental Industrial Hygienists (ACGIH) accepted a lower threshold limit value (TLV) for respirable crystalline silica (RCS) exposure of 25 μg/m3, half of the previous TLV. This change is problematic because the current standard sampling and measurement practices used by NIOSH, OSHA, and MSHA are not sensitive enough to allow an analyst to confidently determine samples acquired near the TLV. In response to this need for a more sensitive method to analyze respirable dust filter samples for crystalline silica, a modification of current NIOSH infrared spectrometric methods is being developed. The additional sensitivity is gained by performing the infrared absorbance measurements at 77 K where absorbance peaks are more intense by virtue of being narrower. A quick-change cryostat has been fabricated such that a sample can be introduced to the spectrometer and cooled to 77 K in 5 min, interrogated for 1 min, and removed and the cryostat readied for another sample in 2 min, for a turnaround time of 8 min per sample, which is brief compared to the time required to prepare and redeposit a sample. Therefore, samples can be acquired and interrogated with legacy samplers, filters, pumps, spectrometers, and sample preparation, the only modification being the addition of a cryostat to the spectrometer. Preliminary experiments demonstrate that the peak-to-background ratio of the quartz signature band near 800 cm-1 increases by approximately 50 % on cooling from room temperature to 77 K. The slopes of the calibration curve derived from standards interrogated at both room temperature and 77 K indicate that the low-temperature method is approximately 25 % more sensitive.
{"title":"Determination of Crystalline Silica in Dust at Low Concentrations by Low-Temperature Infrared Spectrometry.","authors":"W. Chisholm, Taekhee Lee, M. Chirila","doi":"10.1520/STP156520130029","DOIUrl":"https://doi.org/10.1520/STP156520130029","url":null,"abstract":"The American Conference of Governmental Industrial Hygienists (ACGIH) accepted a lower threshold limit value (TLV) for respirable crystalline silica (RCS) exposure of 25 μg/m3, half of the previous TLV. This change is problematic because the current standard sampling and measurement practices used by NIOSH, OSHA, and MSHA are not sensitive enough to allow an analyst to confidently determine samples acquired near the TLV. In response to this need for a more sensitive method to analyze respirable dust filter samples for crystalline silica, a modification of current NIOSH infrared spectrometric methods is being developed. The additional sensitivity is gained by performing the infrared absorbance measurements at 77 K where absorbance peaks are more intense by virtue of being narrower. A quick-change cryostat has been fabricated such that a sample can be introduced to the spectrometer and cooled to 77 K in 5 min, interrogated for 1 min, and removed and the cryostat readied for another sample in 2 min, for a turnaround time of 8 min per sample, which is brief compared to the time required to prepare and redeposit a sample. Therefore, samples can be acquired and interrogated with legacy samplers, filters, pumps, spectrometers, and sample preparation, the only modification being the addition of a cryostat to the spectrometer. Preliminary experiments demonstrate that the peak-to-background ratio of the quartz signature band near 800 cm-1 increases by approximately 50 % on cooling from room temperature to 77 K. The slopes of the calibration curve derived from standards interrogated at both room temperature and 77 K indicate that the low-temperature method is approximately 25 % more sensitive.","PeriodicalId":91202,"journal":{"name":"Annual book of ASTM standards. Section 11, Water and environmental technology. ASTM Committee E-35 on Pesticides","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2013-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84264978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：