Technique for Magnetic Susceptibility Determination in the High Doped Semiconductors by Electron Spin Resonance

Method for determining the magnetic susceptibility in the high doped semiconductors is considered. A procedure that is based on double integration of the positive part of the derivative of the absorption line having a Dyson shape and takes into account the depth of the skin layer is described. Analysis is made for the example of arsenic doped germanium samples at a rather high concentration corresponding to the insulator metal phase transition.Comment: Pages 13, figures 9, references 1

Картезіанство, аргументація, цінності у контексті «нової риторики» Хаїма Перельмана

The article deals with the process of founding and further development of the new rhetoric, a theory of argumentation developed by the Belgian philosopher Chaïm Perelman (1912-1984) and his co-worker Lucie Olbrechts-Tyteca (1899-1987). The intellectual and philosophical backgrounds of the authors and some key characteristics of their theoretical approaches are described. The new rhetoric: (а) is primarily concerned with argument or practical reasoning, (b) suggests that figures of speech may be arguments instead of merely ornaments, (c) with its goal to influence minds, new rhetoric is a dynamic field of study, (d) it is complimentary rather than in opposition to formal reasoning. According to Perelman, the theory of argumentation conceived as a new rhetoric or dialectic, covers the whole range of discourse that aims at persuasion and conviction, whatever the audience addressed and whatever the subject matter. Perelman presents his new rhetoric as a much better form of logic than Cartesian deductive, stringent reasoning, at least where law and other values-based systems are concerned. Perelman challenged the unwholesome assumption that what we cannot know with mathematical certainly is necessarily arbitrary, irrational, and subjective. Perelman recognized "reasoned conviction" as a bridge to knowledge, although he was aware that it was a less perfect source of cognition than verified certainty. It is explained how the idea of developing the new rhetoric was born out of dissatisfaction with logical positivism or neopositivism (The Vienna Circle’s theories and ideas) and which classical and modern sources inspired the authors in developing a specific logic of value judgments that could deal with argumentation about actions, choices, decisions and without dismissing such argumentation as irrational. The rhetorical framework of the theory is expounded and an overview is provided of the key notions and concepts of Perelman’s ‘new rhetoric’ – the notions of adherence, audience (particular and universal audience), persuasion are explained. According to Perelman, the new rhetoric is based on the idea that since argumentation aims at securing the adherence of those to whom it is addressed, it is, in its entirety, relative to the audience to be influenced. Рerelman's position on the difference between formal logic and argumentation is analyzed.В статье исследуются методологические основания общефилософских и теоретико-правовых взглядов Хаима Перельмана, социокультурный контекст, интеллектуальная среда, в который происходило его становление как ученого, формировалась и эволюционировала индивидуально-авторская картина мира. Освещены ключевые моменты его концепции рационального дискурса («неориторики»), появление которой стало важным этапом на пути к формированию современной теории юридической аргументации, походов к правопониманию. Проанализирован оригинальный подход Хаима Перельмана к социальному познанию, рациональности, пониманию роли и значения ценностей и ценностных суждений в теоретических и практических рассуждениях, в аргументации.Досліджено методологічні основи загальнофілософських і теоретико-правових поглядів Хаїма Перельмана, соціокультурний контекст, інтелектуальне середовище, у якому відбувалося його становлення як вченого, формувалася та еволюціонувала індивідуально-авторська картина світу. Висвітлено ключові моменти його концепції раціонального дискурсу («неориторики»), поява якої стала важливою віхою на шляху формування сучасної теорії юридичної аргументації, підходів до праворозуміння. Проаналізовано оригінальний підхід Хаїма Перельмана до соціального пізнання, раціональності, розуміння ролі і значення цінностей та ціннісних суджень у теоретичних і практичних міркуваннях, у аргументації

Optical anisotropy of InAs/GaSb broken-gap quantum wells

We investigate in detail the optical anisotropy of absorption of linearly polarized light in InAs/GaSb quantum wells grown on GaSb along the [001] direction, which can be used as an active region of different laser structures. The energy level positions, the wave functions, the optical matrix elements, and the absorption coefficients are calculated using the eight-band k center dot p model and the Burt-Foreman envelope function theory. In these calculations, the Schrodinger and Poisson equations are solved self-consistently taking the lattice-mismatched strain into account. We find that a realistic Hamiltonian, which has the C (2v) symmetry, results in considerable anisotropy of optical matrix elements for different directions of light polarization and different directions of the initial-state in-plane wave vector, including low-symmetry directions. We trace how the optical matrix elements and absorption are modified when spin-orbit interaction and important symmetry breaking mechanisms are taken into account (structural inversion asymmetry, bulk inversion asymmetry, and interface Hamiltonian). These mechanisms result in an almost 100% anisotropy of the absorption coefficients as the light polarization vector rotates in the plane of the structure and in a plane normal to the interfaces

Electrical excitation of shock and soliton-like waves in two-dimensional electron channels

We study electrical excitation of nonlinear plasma waves in heterostructures with two-dimensional electron channels and with split gates, and the propagation of these waves using hydrodynamic equations for electron transport coupled with two-dimensional Poisson equation for self-consistent electric potential. The term related to electron collisions with impurities and phonons as well as the term associated with viscosity are included into the hydrodynamic equations. We demonstrate the formation of shock and soliton-like waves as a result of the evolution of strongly nonuniform initial electron density distribution. It is shown that the shock wave front and the shape of soliton-like pulses pronouncedly depend on the coefficient of viscosity, the thickness of the gate layer and the nonuniformity of the donor distribution along the channel. The electron collisions result in damping of the shock and soliton-like waves, while they do not markedly affect the thickness of the shock wave front.Comment: 9 pages, 11 figure

Identification of influential patterns of sulfitation treatment of sugar production thick juice and remelt on the beet sugar quality

It is well known that in order to obtain crystalline sugar of a high quality category (Extra and TS1), it is necessary to ensure the production of concentrated sugar-containing intermediates with the lowest possible color, since it is these intermediates that directly determine the color of the resulting crystalline sugar. Laboratory studies have been carried out on the effect of sulfitation treatment using various reagents, namely, sulfurous anhydride and sodium bisulfite, of concentrated intermediates – thick juice and remelt syrup B+C of sugar production on the quality of beet sugar. It has been established that the sulfitation treatment of concentrated intermediates using sulfur dioxide provides a greater reduction in their color compared to sodium bisulfite – from 996,70 to 830,30 and 857,30 ICUMSA units respectively. It has been established that sulfitation treatment with using various reagents of concentrated intermediates provides a decrease in the color of sugar. So, according to the color index, sugar obtained in laboratory conditions from samples obtained using sulfitation treatment, according to the requirements of GOST 33222-2015, corresponds to category TS1, and obtained from an untreated sample, to category TS2. Thus, in a critical situation, sulfitation treatment can provide sugar with a higher quality category. It has been established that during long-term storage (up to 100 days) of concentrated sugar-containing intermediates, their color increases, however, preliminary sulfitation treatment using sulfur dioxide provides the smallest increase in color during storage, compared with treatment with sodium bisulfite. The increase in color after 100 days of storage relative to the initial values was 18,46 and 36,26%, respectively

Improvement of the liquid-jet sulfitators construction to increase the efficiency of sulfitation treatment of sugar production liquids

The article discusses and analyzes the construction of liquid-jet sulfitators used in the beet sugar industry. The importance of sulfitation treatment in the sugar beet processing and raw cane sugar technology is noted and the main advantages of its use at various technological stages are given, namely, preparation of extractant used for diffusion sucrose extraction out of beet cossettes, thin juice processing, thick juice with B- and C-remelts processing, as well as raw cane sugar remelt processing. The advantages and disadvantages of liquid-jet sulfitators in comparison with other constructions are noted and criteria for their improvement are given. It has been noted that the created ejection, which sucks in the sulphitation gas into the contacting chamber, and the fact that the absorption of sulfur dioxide occurs on a larger surface than in other types of structures the main advantages of liquid-jet sulphitators. The main disadvantages are the short length of the contacting chamber, which is insufficient for ensuring complete absorption of sulfur dioxide, as well as instability of the generated ejection when the productivity changes. This determines the criteria given in the article for the improvement of liquid-jet sulfitators. The description of the developed construction of the sulphitator centrifugal-jet nozzle of sugar production liquids is given, which provides: the stability of the sulphitation gas supply in a wide range of plant productivity; stability of the hydroaerodynamic regime of the system «treated liquid – sulphitation gas» inside the sulphitator; sufficient contact time for complete dissolution in the treated liquid of the sulfur anhydride contained in the sulphitation gas. The advantages of the developed centrifugal-jet sulfitators in comparison with typical liquid-jet sulfitators are noted: ensuring the operation range of 50-120% of the nominal capacity (plant production capacity); significant reduction in the technical sulfur consumption for the sulphur anhydride production, which is used as a reagent for the sulfitation treatment of liquids in beet sugar processing; reduction of harmful emissions into the atmosphere due to 100 % sulfur anhydride dissolution in the treated liquid

Экспериментальные и численные исследования диаграмм обратного рассеяния блоков маскирующих цифровых двухбитных метапокрытий

Introduction. The scattering patterns of non-absorbing coded checkerboard-like meta-coatings (MCs) applied for reducing the radar cross section (RCS) of metal surfaces inevitably contain side diffraction lobes. Therefore, the development of MCs with a low level of diffraction lobes is relevant. For this purpose, it is proposed to use checkerboard-like MCs in the form of a set of several basic flat blocks with the same dimensions. The paper discusses two such basic MC blocks with different coding matrices. The cells of the metasurface contain two coupled elliptical ring resonators and are distinguished by a 2-bit coding of the tilt angle of the anisotropy axis. Coding matrices of the MC blocks are built according to the block principle.Aim. To investigate experimentally and numerically backscatter patterns (BSP) for consonant (co-) and orthogonal (cross-) polarizations of the two developed flat blocks of the 2-bit digital nonabsorbing anisotropic MCs for different planes and polarizations of irradiation.Materials and methods. Full-wave simulation of the MC blocks was carried out using the HFSS software by the finite element method. BSP measurements of the fabricated MC layouts were performed in an anechoic chamber of the Center for Collective Usage “Applied Electrodynamics and Antenna Measurements” of the Southern Federal University using an automated information and computing complex.Results. The RCS reduction for the two blocks under normal irradiation is approximately the same and not less than 12 dB over the 9.8…21 GHz band. A good matching between the simulation and measurement results of backscattering patterns of the blocks in the region of the central lobes for various planes and polarizations of the irradiation is noted. In the principal planes, the blocks cancel the central lobes of the BSP by 10…25 dB; in the sector of angles of around ±40°, the backward RCS of the blocks is lower than that of the reference. In the diagonal planes, there is a cancellation of the RCS by 13…15 dB and an expansion of the central lobe of the BSP for copolarizations, as well as a bifurcation of this lobe for crosspolarizations in the sector of angles ±9°; outside of this sector the RCSs of the blocks are commensurate with the RCS of the reference.Conclusion. The developed blocks of the 2-bit digital nonabsorbing anisotropic MCs can be used for broadband cancellation of the RCS of metal surfaces.Введение. Диаграммы рассеяния непоглощающих кодированных шахматно-подобных метапокрытий (МП) для снижения эффективной площади рассеяния (ЭПР) металлических поверхностей объектов неизбежно содержат боковые дифракционные лепестки. В связи с этим актуальна разработка МП с низким уровнем дифракционных лепестков. С этой целью предложено использовать шахматно-подобные МП в виде набора нескольких основных плоских блоков с одинаковыми размерами. В статье рассмотрены 2 таких основных блока МП с разными матрицами кодирования. Ячейки метаповерхности содержат связанные эллиптические кольцевые резонаторы и отличаются двухбитным кодированием угла наклона оси анизотропии. Матрицы кодирования блоков МП построены по блочному принципу.Цель работы. Экспериментально и численно исследовать диаграммы обратного рассеяния (ДОР) на согласованной (ко-) и ортогональной (кросс-) поляризациях двух разработанных плоских блоков двухбитных цифровых непоглощающих анизотропных МП для различных плоскостей и поляризаций облучения.Материалы и методы. Полноволновое моделирование блоков МП выполнено в программе HFSS методом конечных элементов. Измерения ДОР изготовленных макетов МП проведены на автоматизированном информационно-вычислительном комплексе АИВК-ТМСА-1.0-40.0-ДБ3/TD,FD в безэховой камере ЦКП "Прикладная электродинамика и антенные измерения" Южного федерального университета.Результаты. Снижение моностатических ЭПР двух блоков при нормальном облучении примерно одинаково и составляет не менее 12 дБ в полосе от 9.8 до 21 ГГц. Отмечено хорошее совпадение результатов полноволнового моделирования и измерения ДОР блоков разработанных метапокрытий в области центральных лепестков для различных плоскостей и поляризаций облучения. В главных плоскостях блоки гасят центральные лепестки ДОР на 10…25 дБ; в секторе углов около ±40° обратная ЭПР блоков ниже, чем у эталона. В диагональных плоскостях наблюдается гашение ЭПР на 13…15 дБ и расширение центрального лепестка ДОР на кополяризациях, а также раздвоение этого лепестка на кроссполяризациях в секторе углов ±9°. Вне этого сектора ЭПР блоков соизмерима с ЭПР эталона.Заключение. Разработанные блоки двухбитных цифровых непоглощающих анизотропных МП могут применяться для широкополосного гашения ЭПР металлических поверхностей

Application of the iterative approach to modal methods for the solution of Maxwell's equations

In this work we discuss the possibility to reduce the computational complexity of modal methods, i.e. methods based on eigenmodes expansion, from the third power to the second power of the number of eigenmodes by applying the iterative technique. The proposed approach is based on the calculation of the eigenmodes part by part by using shift-and-invert iterative procedure and by utilizing the iterative approach to solve linear equations to compute eigenmodes expansion coefficients. As practical implementation, the iterative modal methods based on polynomials and trigonometric functions as well as on finite-difference scheme are developed. Alternatives to the scattering matrix (S-matrix) technique which are based on pure iterative or mixed direct-iterative approaches allowing to markedly reduce the number of required numerical operations are discussed. Additionally, the possibility of diminishing the memory demand of the whole algorithm from second to first power of the number of modes by implementing the iterative approach is demonstrated. This allows to carry out calculations up to hundreds of thousands eigenmodes without using a supercomputer

Spin-related phenomena in InAs/GaSb quantum wells

We have studied theoretically the influence of symmetry breaking mechanisms: structural inversion asymmetry, bulk inversion asymmetry, relativistic and non-relativistic interface Hamiltonian and warping on spin split of levels Delta E and optical absorption of linearly polarized light in asymmetrical quantum wells made from zincblende materials grown on [001] direction. The AlSb/InAs/GaSb/AlSb broken-gap quantum wells with hybridized electron-hole states sandwiched by the AlSb barriers have been considered. We have obtained substantial contributions of these effects into the absolute values of spin split of electron and hole states and spinflip optical transitions for the initial state in-plane wave vectors along low symmetry directions such as [12]