Controllable switching of vortex chirality in magnetic nanodisks by a field pulse

We propose a way of fast switching the chirality in a magnetic nanodisk by applying a field pulse. To break the symmetry with respect to clockwise or counterclockwise chirality a mask is added by which an inhomogeneous field influences the vortex state of a nanodisk. Using numerical spin--lattice simulations we demonstrate that chirality can be controllably switched by a field pulse, whose intensity is above some critical value. A mathematical definition for the chirality of an arbitrary shaped particle is proposed.Comment: REVTeX, 4 pages, 3 figure

Improving the Theoretical and Methodological Framework for Implementing Digital Twin Technology in Various Sectors of Agriculture

The aim of this study is to systematize and improve the theoretical and methodological framework for implementing digital twin technology. The study focuses on digital twins in agriculture. This paper is designed to solve the scientific problem associated with the development of a methodological framework for the implementation of digital twins in the work of agricultural organizations. Using methods of analysis of socio-economic phenomena and processes on the basis of a set of scientific approaches, economic-statistical analysis, and others, the study considers the importance of digital twins of agricultural machinery and equipment, identifies trends in agriculture determined by digitalization, and suggests promising areas for digital twins of agricultural machinery and equipment. This paper also examines the theoretical basis for the implementation of digital twin technology in the agricultural sector of production. New research results complement the theoretical provisions on the essence of digital twin technology; develop the methodological provisions of digital twin technology, represented by the study of their significance, principles, and features of operation. The study may be seen as academically novel as it reveals the prerequisites for implementing digital technology in agriculture as well as clarifies and improves the theoretical and methodological provisions of the application of digital twin technology in various sectors of agriculture. Doi: 10.28991/ESJ-2023-07-04-05 Full Text: PD

Combination of fluorescent and spin labels: a powerful method for the optimization of hydrophilic membranes for the separation of oil-in-water emulsions

A new method for assessing the quality of fibre coating based on a combination of fluorescence microscopy and electron paramagnetic resonance is presented in this work. An influence of the carboxymethylcellulose/polyvinylamine gel preparation method on the mobility of the spin label was established. The mobility of the spin label changes from 3.5 ns in the case of a polyvinylamine solution to 12.8 ns in the case of a cross-linked gel on the surface of the glass fibre. A qualitative relationship was found between the mobility of the spin label in the gel applied to the glass fibre and the rate of spreading of crude oil over its surface. This method can be used to make membranes for the separation of water-in-oil emulsions

Internal control system in enterprise management : analysis and interaction matrices

This study is aimed at the development of a guideline for analysis of the economic activity of an enterprise to control and ensure the interaction of tasks and functions of management in the current and strategic aspects in the conditions of innovative development. The proprietary methodology for enterprise management control system formation is developed. The concept of matrices of analysis and interaction between the functions of the enterprise management is introduced. The matrix of operational control and management, the matrix of strategic control and management, the matrix of integrated control and management are considered by the authors. The concept of enterprise management control is considered herein. The objectives of the management control system in the modern economy are also described. The key role of control in the implementation of the current and strategic objectives of the enterprise management is substantiated. The proposals are formulated to improve the control function at the enterprise with the help of new information technologies. Based on the proprietary methodology of matrix analysis and interaction of objectives and functions of the enterprise management system, the algorithm for the formation of a system of integrated flexible internal control is developed.peer-reviewe

Innovation process and control function in management

Currently, in terms of the need to improve business competitiveness in world markets, the problem of innovative development and the control function of Russian enterprises becomes more relevant. The authors’ approach, revealing the role of management control in solving the problem of innovative development of an enterprise, is presented herein. As the main method of study, the multilevel approach is used, while the innovation process is explored in various representations. As a set of stages from an innovational concept to a market product; as a set of resources and motivations for the participants in an innovational project; as a set of rules and procedures aimed to achieving the goals and requiring constant monitoring. Managerial control is considered as a factor of integration of the conditions required for the successful implementation of an innovative project at the enterprise. For the integrated support of the innovative processes, the enterprise internal control system is proposed, based on the polyadministrative matrix structure and the frame functioning model of the enterprise using information technologies. The systems of internal control during innovative development, which is implemented in different conditions and in different national economic systems, are also considered. The advantages and disadvantages of various approaches to the organization of control over the innovation activity at the enterprise are revealed. The recommendations are formulated to improve the model of internal control in the conditions of innovative development of the enterprise.peer-reviewe

Luminescent coordination polymers based on Ca²⁺ and octahedral cluster anions [{M₆Clⁱ₈}Clᵃ₆}²⁻ (M = Mo, W) : synthesis and thermal stability studies

Luminescent coordination polymers (CPs) based of inexpensive stable precursors are attractive materials for applications. Here we report the synthesis and evaluation of the stability and photophysical characteristics of the first examples of phosphorescent CPs based on octahedral molybdenum and tungsten cluster anions. Specifically 1D CP trans-[{Ca(OPPh₃)₄}{{M₆Clⁱ₈}Clᵃ₆}]∞ (M = Mo, W) can be obtained either directly at increased temperature or via intermediate phases [cis-Ca(OPPh₃)₄(H₂O)₂][{M₆Clⁱ₈}Clᵃ₆]∙2CH₃CN that are stable at room-temperature, but convert to the titled CP at temperatures above 100 °C

Phase Randomness in a Semiconductor Laser: the Issue of Quantum Random Number Generation

Gain-switched lasers are in demand in numerous quantum applications, particularly, in systems of quantum key distribution and in various optical quantum random number generators. The reason for this popularity is natural phase randomization between gain-switched laser pulses. The idea of such randomization has become so familiar that most authors use it without regard to the features of the laser operation mode they use. However, at high repetition rates of laser pulses or when pulses are generated at a bias current close to the threshold, the phase randomization condition may be violated. This paper describes theoretical and experimental methods for estimating the degree of phase randomization in a gain-switched laser. We consider in detail different situations of laser pulse interference and show that the interference signal remains quantum in nature even in the presence of classical phase drift in the interferometer provided that the phase diffusion in a laser is efficient enough. Moreover, we formulate the relationship between the previously introduced quantum reduction factor and the leftover hash lemma. Using this relationship, we develop a method to estimate the quantum noise contribution to the interference signal in the presence of phase correlations. Finally, we introduce a simple experimental method based on the analysis of statistical interference fringes, providing more detailed information about the probabilistic properties of laser pulse interference

Кремниевая электронно-чувствительная pin-линейка, облучаемая с обратной стороны

Introduction. In recent decades, in the field of photoelectronics, special attention has been paid to the development of semiconductor matrix photodetectors. These detectors have become an effective alternative to existing television receiving systems. Among such devices, linear position-sensitive sensors are used in cases where the rapid registration of changes to the environment is required (for instance, high-speed locators for flying vehicles).Aim. To develop a strip of silicon pin-diodes as part of a hybrid IR-detector for effective registration of photoelectrons with time resolution less than 10 ns, as well as to model the key electro-physical characteristics of the strip.Materials and methods. In the device under development, the registration of photoelectrons is achieved by the presence of a near-surface field using p ++–p junction formed by diffusion of boron into the silicon with resistivity of 3 kΩ · cm. The pulling field is also formed in the space charge region between p ++ - and n ++ -regions. Diffusion of phosphorus was carried out to create the n ++ -region. Numerical calculations of potential distribution, concentration of free charge carriers and currents were carried out using software for 1D- and 2D-modelling (SimWin and TCAD Synopsys).Results. 2D-calculation of charge carrier concentration and potential distribution was performed. The study determined the minimum bias for the complete depletion of the i-layer, including that for longitudinal grooves of various depths. The strip was tested as part of a hybrid photoelectric device by irradiating light pulses from IR LED. When the voltage on the diodes was reached –270 V, the duration of the signal front on all channels was 5…9 ns.Conclusion. For use in IR-hybrid detectors, a strip of 12 silicon pin-diodes was developed with a sensitive element of 24 × 0.2 mm in dimension. The study of pulse characteristics showed that the necessary duration of the front signal on all channels was achieved without thinning thus satisfying the requirements for high-speed position-sensitive sensor of the infrared radiation.Введение. В последние десятилетия в фотоэлектронике особое внимание уделяется разработке полупроводниковых матричных фотоприемных устройств, которые фактически стали эффективной альтернативой существующим аналоговым телевизионным приемным системам. Среди таких устройств линейные позиционно-чувствительные датчики применяются для регистрации быстрых изменений в окружающей обстановке и их последующей обработки (например, быстродействующие локаторы летательных аппаратов).Цель работы. Создание линейки кремниевых pin-диодов для использования в составе гибридного детектора ИК-излучения с целью регистрации фотоэлектронов с временны́м разрешением лучше 10 нс. Моделирование основных электрофизических характеристик линейки.Материалы и методы. В разрабатываемом приборе регистрация фотоэлектронов обеспечивается за счет наличия приповерхностного поля при использовании p ++–p-перехода, сформированного диффузией бора в кремний с удельным сопротивлением 3 кОм · см. Тянущее поле, в свою очередь, также формируется в области объемного заряда между p ++ - и n ++ -областями. Для создания n ++ -области проводилась диффузия фосфора. Численные расчеты распределения потенциала, концентрации свободных носителей заряда и токов проводились в программных пакетах одномерного (SimWin) и двумерного (TCAD Synopsys) моделирования.Результаты. Проведен двумерный расчет распределения концентрации свободных носителей заряда и потенциала в исследуемой pin-структуре. Определены минимальные напряжения, обеспечивающие полное обеднение i-слоя, в том числе для случая продольной канавки различной глубины. Линейка тестировалась в составе гибридного фотоэлектронного прибора облучением световыми импульсами от ИК-светодиода. При напряжении на диодах линейки –270 В достигнута длительность фронта сигнала на всех каналах 5...9 нс.Заключение. Для гибридного детектора ИК-излучения разработана линейка из 12 кремниевых pin-диодов, с размерами чувствительной области элемента 24 × 0.2 мм. По результатам исследований импульсной характеристики показано, что без операции утонения достигнута длительность фронта сигнала на всех каналах, удовлетворяющая требованиям к быстродействующему позиционно-чувствительному датчику ИК-излучения