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

Исследование по возделыванию трититригии в полузасушливой зоне

Over the course of several years of meticulous selection, The Tsitsin Main Moscow Botanical Garden of Academy of Sciences, successfully cultivated a novel trititrigia crop, characterized as a hybrid between wheat and couch grass. The intrinsic potential of this crop, as highlighted by the authors, instigated a keen interest in its investigation. (Research purpose) To conduct research on the cultivation of trititrigia Pamyati Lyubimovoy (In Memory of Lyubimova) in the semi-arid southern zone of the Rostov region. (Materials and methods) Trititrigia was cultivated on typical chernozem soil with carbonate content, characterized by heavy loamy texture, in conditions of insufficient and unstable moisture, following the zonal technology for cultivating winter wheat. The main pre-sowing tillage was performed using a shallow method by a combined KUM-4 unit. For seed sowing, the «Demetra» selective seeder was used. Throughout the trials from October 2020 to August 2022, meteorological conditions were taken into account, including precipitation levels and air temperature. Using two crops as examples, the biometric data of trititrigia plants, yield structure elements, combine yield and drought resistance were studied. (Results and discussion) It is determined that trititrigia Pamyati Lyubimovoy (In Memory of Lyubimova) aligns with the declared parameters in terms of plant height, ear length, and duration of the vegetative period. The plant development type of trititrigia is identical to winter wheat. (Conclusions) It is established that trititrigia Pamyati Lyubimovoy (In Memory of Lyubimobva) shows low resistance to drought within a semi-arid climate. Additionally, the straw yield surpasses the grain yield by a factor of four, while the weight of 1000 grains is low at 23.58 grams. Moreover, the combine yield (3.80 tons per hectares) falls short compared to the winter wheat variety Stanichnaya (5.09 tons per hectares). Further investigations into trititrigia within a semi-arid climate are considered necessary to determine its cultivation feasibility.В Главном ботаническом саду им. Н.В. Цицина Российской академии наук путем многолетней селекции была выведена новая культура трититригия, представляющая собой пшенично-пырейный гибрид. Анонсированный авторами потенциал данной культуры послужил мотивацией к ее изучению. (Цель исследования) Провести исследования по возделыванию трититригии сорта Памяти Любимовой в полузасушливой южной зоне Ростовской области. (Материалы и методы) Трититригию выращивали на черноземе обыкновенном карбонатном тяжелосуглинистом в условиях недостаточного и неустойчивого увлажнения в соответствии с зональной технологией возделывания озимой пшеницы. Основную обработку почвы до предпосевного состояния проводили мелким способом с применением комбинированного агрегата КУМ-4. Для посева семян использовали селекционную сеялку «Деметра». В ходе испытаний с октября 2020 по август 2022 года учитывали метеорологические условия: количество осадков и температуру воздуха. На примере двух посевов изучали биометрические данные растений трититригии, элементы структуры урожая, комбайновую урожайность и засухоустойчивость. (Результаты и обсуждение) Определили, что трититригия Памяти Любимовой по высоте растения, длине колоса, продолжительности вегетационного периода соответствует заявленным оригинаторами сорта параметрам. Тип развития растений трититригии идентичен озимой пшенице. (Выводы) Определили, что культура трититригии Памяти Любимовой проявляет низкую устойчивость к засухе в полузасушливым климате, урожай соломы превышает урожай зерна в 4 раза, масса 1000 зерен низкая – 23,58 грамма комбайновая урожайность (3,80 тонны на гектар) ниже чем озимой пшеницы сорта Станичная (5,09 тонны на гектар). Отметили необходимость дальнейших исследований трититригии в полузасушливом климате для выявления целесообразности ее возделывания

Data from an International Multi-Centre Study of Statistics and Mathematics Anxieties and Related Variables in University Students (the SMARVUS Dataset)

This large, international dataset contains survey responses from N = 12,570 students from 100 universities in 35 countries, collected in 21 languages. We measured anxieties (statistics, mathematics, test, trait, social interaction, performance, creativity, intolerance of uncertainty, and fear of negative evaluation), self-efficacy, persistence, and the cognitive reflection test, and collected demographics, previous mathematics grades, self-reported and official statistics grades, and statistics module details. Data reuse potential is broad, including testing links between anxieties and statistics/mathematics education factors, and examining instruments’ psychometric properties across different languages and contexts. Data and metadata are stored on the Open Science Framework website [https://osf.io/mhg94/]

Data from an International Multi-Centre Study of Statistics and Mathematics Anxieties and Related Variables in University Students (the SMARVUS Dataset)

This large, international dataset contains survey responses from N = 12,570 students from 100 universities in 35 countries, collected in 21 languages. We measured anxieties (statistics, mathematics, test, trait, social interaction, performance, creativity, intolerance of uncertainty, and fear of negative evaluation), self-efficacy, persistence, and the cognitive reflection test, and collected demographics, previous mathematics grades, self-reported and official statistics grades, and statistics module details. Data reuse potential is broad, including testing links between anxieties and statistics/mathematics education factors, and examining instruments’ psychometric properties across different languages and contexts. Data and metadata are stored on the Open Science Framework website (https://osf.io/mhg94/).</p&gt

Data from an International Multi-Centre Study of Statistics and Mathematics Anxieties and Related Variables in University Students (the SMARVUS Dataset)

This large, international dataset contains survey responses from N = 12,570 students from 100 universities in 35 countries, collected in 21 languages. We measured anxieties (statistics, mathematics, test, trait, social interaction, performance, creativity, intolerance of uncertainty, and fear of negative evaluation), self-efficacy, persistence, and the cognitive reflection test, and collected demographics, previous mathematics grades, self-reported and official statistics grades, and statistics module details. Data reuse potential is broad, including testing links between anxieties and statistics/mathematics education factors, and examining instruments’ psychometric properties across different languages and contexts

THE INFLUENCE OF THE COVID-19 PANDEMIC ON THE LABOR MARKET IN RUSSIA

Статья посвящена изучению рынка труда в России после пандемии COVID-19. В работе приведены примеры изменений, произошедших на рынке труда, спровоцированные коронавирусными ограничениями. Приведены статистические данные, результаты опросов и исследований.The article is devoted to the study of the labor market in Russia after the COVID-19 pandemic. The paper provides examples of changes that have occurred in the labor market, provoked by coronavirus restrictions. Statistical data, survey and research results are presented

Recommendations of the Russian Gastroenterological Association on Clinical Use of High-Resolution Manometry in Diagnosis of Esophageal Disorders

Aim. Current recommendations of the Russian Gastroenterological Association on clinical use of high-resolution manometry in diagnosis of esophageal disorders are intended to assist in clinical decision making, terminology standardisation and interpretation of clinical data.Key points. In 2018, a joint meeting of the Russian Gastroenterological Association and Russian Neurogastroenterology and Motility Group approved unified terminology and classification of esophageal motor function disorders for high-resolution manometry diagnosis.Gastrointestinal patient complaints typically concern esophageal disorders such as dysphagia, regurgitation, heart-burn, chest pain or belching. To exclude erosive and ulcerative lesions, eosinophilic esophagitis and organic changes, esophagogastroduodenoscopy and biopsy are recommended in pre-treatment. Upon excluding mucosal lesions and esophageal lumen obstruction as causal for symptoms, use of high-resolution manometry is recommended. This method of esophageal examination has become the “gold standard” in diagnosis of motor disorders.High-resolution manometry enables detailed investigation of integral quantitative and qualitative characteristics of esophagus motor function and specific related disorders, analysis of esophageal contractile propagation and strictly coordinated synchronous peristalsis of upper esophageal sphincter, esophagus and lower esophageal sphincter, which malfunction may provoke development of achalasia, esophagospasm, hiatal hernia, ineffective eso pha geal motility and other motor disorders.Conclusion. High-resolution manometry is a relatively new method for study of esophagus motor function gaining increasingly wide application in clinical practice. It enables a medical professional to obtain evidence that may critically affect the choice of optimal patient care strategy and effective treatment. Current recommendations are based on an extensive review of up-to-date information and will be updated with new corpus of clinical data and assessment emerging in evidential medicine to provide gastroenterologists country-wide with latest scientific and practical guidelines

Spheroidal cap configurations of atomic clusters on planar surfaces

Deposited atomic cluster configurations are investigated under the hypothesis of spheroidal cap shapes being a stable geometry. The macroscopic-microscopic method is employed to calculate the deformation energy. A new specialized single-particle model is developed in order to account for the quantum effects, and the liquid-drop approach is used to calculate the macroscopic part of the energy. The minima within the total deformation energy are interpreted as equilibrium states of atomic clusters on surfaces. Calculations have been performed for the metallic clusters of Na with atom numbers N = 20, 70 and 200