Hasil untuk "Electric apparatus and materials. Electric circuits. Electric networks"

Shubham Tyagi, Paresh C. Rout, Shubham Singh et al.

ABSTRACT We investigate the influence of hydrostatic pressure on the physical properties of monolayer FeCl2 for spintronics applications. A phase transition from a ferromagnetic half‐metal to a ferromagnetic semiconductor is unveiled at 4.6 GPa, accompanied by a transition from a non‐polar (1T) to a polar (1H) structure. We demonstrate that hydrostatic pressure elevates the Curie temperature above room temperature (for example, 618 K at 5 GPa) and enhances the magnetic anisotropy energy (for example, 731 μeV per formula unit at 5 GPa). A significant Dzyaloshinskii‐Moriya interaction is present in the 1H structure (due to the broken spatial inversion symmetry) and increases with the hydrostatic pressure. Together with the observation of in‐plane electric polarization (for example, 1.1 pCcm−1 at 5 GPa), this positions the 1H structure as a pioneer in the class of 2D materials. Exploiting the phase transition of monolayer FeCl2, a single‐material magnetic tunnel junction is proposed and an outstanding tunneling magnetoresistance ratio is demonstrated.

Zuchong Yang, Daniele Zucchelli, Melissa Berteau‐Rainville et al.

Abstract Polymer semiconductors hold great potential as active materials in (opto)electronic, thermoelectric, and biomedical devices. Their charge transport performance has seen tremendous progress, with mobilities exceeding 1 cm2 V−1 s−1 for a variety of donor‐acceptor copolymers. Nevertheless, charge injection at the metal/polymer interface is still rather ineffective and poorly understood. In a field‐effect transistor, this process is manifested by the contact resistance (Rc) which, for polymers, is several orders of magnitude higher than for their inorganic counterparts. Therefore, an in‐depth investigation of the charge injection in metal/donor‐acceptor polymer systems is sought‐after. Here, the low‐temperature dependent Rc and charge transport of a model isoindigo donor‐acceptor copolymer‐based transistor are studied. The metal/polymer interface is tuned by functionalizing the electrodes with different thiolated self‐assembled monolayers (SAMs). Rc in devices with SAM‐functionalized electrodes is generally lower and exhibited a weak temperature dependence. Counterintuitively, electrodes functionalized with SAMs expected to lead to an apparently unfavorable energy level alignment displayed the lowest Rc. The Fermi level is found to be pinned at all the encompassed interfaces. An energy‐level alignment modeling is employed to understand this behavior. The findings reveal that simply looking at the energy levels alignment of metal/polymer interface does not necessarily lead to reduced Rc.

Sandra Costanzo, Giovanni Buonanno

This work introduces a probabilistic approach for aperiodic time-modulated arrays tailored to simultaneous multi-beam applications. Specifically, they include on-off RF switches that contribute to amplitude tapering, as in <italic>&#x201C;classic&#x201D;</italic> time-modulated arrays, while the spacing is aperiodic, so it is possible to obtain large distances between the elements, in terms of wavelength, without the appearance of grating lobes. The significant spacing allows also a reduction of the deleterious impact of mutual coupling. The proposed aperiodic time-modulated arrays are broadband in the sense that the carrier frequency can potentially span a wide bandwidth without the appearance of grating lobes, independently on the element placement, and they are high-resolution in the sense that the array aperture can be made <italic>&#x201C;electrically&#x201D;</italic> very large regardless the number of elements. The array factor can be controlled simultaneously and independently via switching timing and element positioning. In addition, the proposed arrays are reconfigurable in the sense that a change in the duty cycles of the switches can relatively easily change the shape of the radiation pattern. Furthermore, the presented mathematical modeling allows for obtaining simultaneous beams.

Yinbo Liu, Haixin Du, Wanting You et al.

Moisture-electric generation (MEG), a technology that captures chemical energy from environmental moisture and converts it into sustainable electricity, has attracted significant attention in the field of flexible wearable electronics. However, existing MEG systems still face critical challenges such as low output voltage, poor current stability, and insufficient mechanical properties of materials. Herein, a poly(acrylic acid) (PAA)/choline chloride (ChCl) eutectogels (PA-C) with a "covalent bond-ion pair-hydrogen bond" triple network structure was prepared via ultraviolet photopolymerization by constructing an acrylic acid (AA)/ChCl deep eutectic solvent (DES). Specifically, the cross-linking agent N,N'-methylenebis(acrylamide) (MBA) forms covalent cross-links with AA to provide a rigid framework for PA-C. Meanwhile, hydrogen bonds between PAA chains, as well as ion pairs and hydrogen bonds between PAA and ChCl, form a reversible physical cross-linking network. These networks synergistically endow PA-C with excellent hydrophilicity and mechanical properties. The effect of the molar ratio of AA to ChCl on the microstructure and properties of PA-C was systematically investigated. The results show that under an appropriate AA/ChCl molar ratio, PA-C exhibits a tensile strength of 4.92 MPa and an elongation at break of 633% simultaneously. The MEG developed based on PA-C achieves a high ionic conductivity of 0.54 S m-1 under relative humidity (RH) of 99%. A single MEG device can deliver an open-circuit voltage (Voc) of 1.28 V and a short-circuit current (Isc) of 2.20 mA, with a maximum power density of 90 μW cm-2. Through series and parallel integration, the voltage and current can be flexibly adjusted, enabling direct power supply to light-emitting diodes (LEDs) and low-power devices. This study not only provides a material system for the design of high-performance MEG devices but also opens up an avenue for the development of efficient, scalable, and flexible multifunctional power sources.

Quanhua Chen, Xiang Wan, Walid Boukhili et al.

Abstract The impact of Al/Ti electrodes on enhancing the performance and operational stability of n‐channel organic electrolyte‐gated transistors (OEGTs) is investigated. Utilizing Al/Ti electrodes as source and drain electrodes in diketopyrrolopyrrole (DPP)‐based polymeric semiconductor OEGTs leads to a significant decrease in the charge injection barrier for electrons, resulting in improvement of all electrical parameters including on‐current, mobility, on‐off ratio, and threshold voltages. Furthermore, through a comparative analysis of transistors utilizing polymer insulators and solid electrolytes as gate dielectrics, the effect of alterations in the electrodes on the contact resistance of each device is examined. In comparison to OEGTs with Au electrodes, OEGTs with Al/Ti electrodes demonstrate higher operational stability following multiple cycling tests. Finally, the OEGTs produced in this study demonstrate reliable short‐term memory characteristics, which are subsequently utilized for reservoir computing, achieving a high recognition accuracy of 94% for spoken digits.

Yuanbo Wang, Jingyan Zhang, Pengwei Dou et al.

Abstract Magnetization switching driven by spin‐orbit torques (SOTs) in perpendicular single magnets contributes to the development of high‐efficiency next‐generation spintronic memory and logic. However, the in‐plane magnetic fields required for deterministic magnetization switching in single magnets hamper the design of all‐electric‐control devices. Herein, a simple, efficient, and reliable all‐electric‐control magnetization switching in a sputtered single L10‐FePt film with an artificial lateral gradient is reported. The deterministic magnetization switching exhibits a strong angle dependence and can be effectively tuned through lateral asymmetry. A maximum self‐switching ratio of 18% is achieved without magnetic fields. The structural characterization results reveal that this deterministic magnetization self‐switching can be primarily attributed to the ordering degree gradient. Furthermore, a programmable Boolean logic device together with a full adder is constructed using the single L10‐FePt magnet. The findings of the study highlight an effective route to accomplish electrical spin manipulation in single magnets. This enables the design of purely electrically controlled SOTs‐based logic and in‐memory computing.

Mohamed Rayane LAKEHAL, Amine MEZENNER, Naouel ARAB et al.

The estimation of plant disease intensity is essential for various purposes, including monitoring epidemics, understanding yield loss, and evaluating treatment effects. Despite the availability of sensor technology to measure disease severity using the visible spectrum or other spectral range imaging, deep learning has emerged as a recent and advanced technique for image processing and data analysis. To enhance the severity estimation in diseased leaves, a CNN ensemble is proposed by fusing deep features extracted from outputs of fully connected layers of various CNN models. A SVM (Support Vector Machine) is utilized to achieve the classification stage. Experiments are carried out on wheat leaf images infected by the Yellow rust disease. Experiments conducted using three CNN models that are VGG16, MobileNetV2 and a customized CNN reveal that the CNN ensemble outperforms individual models.

A. Lisov, A. Vozmilov

Aim. The analysis of possibilities and prospects of development of an electronic differential system for electric vehicles based on artificial neural networks. Materials and Methods. We discuss the key advantages of the proposed system, such as its customization capability to various vehicle designs, integration of additional sensors, support for self-driving mode and the ability to interact with the ABS system. Results. We considered the ways to improve the model, including the introduction of self-learning algorithms, optimization of inverter circuits for controlling multiple motors, and implementation of all-wheel drive configurations. In addition, we discuss the customization of the electronic differential system for operation on low-power devices using quantization, pruning and architecture simplification methods. Conclusion. The proposed approaches and algorithms have the potential for widespread deployment in the electric vehicle industry, opening new vistas for development of intelligent vehicle control systems.

Catalin-Mihai Popa, D. Gabor, Anamaria Daroczi

The underground and surface mining industry are a complex sector of activity in which the workers involved face difficult working conditions, manifested by high temperatures, high humidity, risks of collapses, explosions and toxic gases, which requires ensuring a high level of occupational safety. In the case of the use of cable networks in underground and surface mining operations, in order to reduce the risk of explosion and increase the level of occupational safety, they must include electrical cables manufactured in accordance with the requirements of specific standards and which must be checked and certified for this purpose. In order to be certified in the voluntary field, power cables intended for use in the underground and surface mining industry must have a robust construction to withstand the mechanical stresses of exploitation, be able to provide appropriate electrical and thermal protection, and be made of materials that prevent the spread of fire.The danger represented by the use in areas endangered by the presence of gray dust of electrical power cables made of poor-quality materials and with an inappropriate construction for the respective environment, is materialized by the possibility of short circuits that generate heat, electric arcs and metal splashes, resulting in the initiation of fires and/or explosions. This paper presents the safety requirements, test methods and test stand for mining electrical cables for their certification in the voluntary field.

S. Kurilin, V. V. Fedotov

The research is aimed at improving the reliability of complex technical systems, including a component such as an asynchronous electric motor, by monitoring their current state. The general objective of the study is to substantiate the possibility of using such a factor as the stator current vector, the oscillations of which are taken as an observable parameter, to diagnose a fault in the mechanical circuit of an electric motor. To substantiate the legitimacy of such a decision, a mathematical modeling apparatus was used with a computational experiment. For this purpose, the purpose and conditions for its implementation were preliminarily formulated, which made it possible to obtain a sufficient evidence base. The mathematical model of an asynchronous electric motor is supplemented with pulse load functions in the form of Fourier series, represented by rectangular alternating and constant sign pulses, the repetition frequency of which is equal to the rotational speed of the electric motor shaft. To conduct a computational experiment, a problem-­oriented algorithm and a Maple program were developed. An original feature of the mathematical model, algorithm and program is the linking of the load torque with the angle of rotation of the rotor, which is typical for damaged mechanical circuits of asynchronous electric motors. Using a mathematical model, the effects on a serial asynchronous electric motor of load torque pulses from a damaged bearing are revealed, as well as the effects of torque pulses from periodic impacts occurring in a damaged mechanical circuit. In both cases, oscillations of the modulus of the stator current vector were recorded, coinciding with the rotor rotation frequency. The results of the computational experiment indicate that stator current fluctuations make it possible to reliably judge the state of the mechanical circuit of the electric motor. The research materials can be used by operating organizations to create systems for instrumental monitoring of the current technical condition of a fleet of asynchronous electric motors.

Tomas Blecha, Martin Hirman, Jiri Navratil

This article deals with the issue of assembling conventional SMD components on textile substrates using UV-curable non-conductive adhesives. This technology is easily applicable in the textile industry. It thus enables the easy and fast production of e-textiles that are equipped with conventional electronic components or even entire electronic modules. The article describes the principle of this innovative technology. Furthermore, comprehensive results of testing the effect of mechanical stress, chemical cleaning, and climatic changes on e-textiles with assembled SMD components on the change in contact resistance are presented here. The results show that this technology can be used for assembling and encapsulating SMD components on a textile substrate in the realization of e-textiles.

Paula Palacios, Abdelrahman M. Askar, Francisco Pasadas et al.

Abstract This work presents a 2D tellurium (Te)‐based diode that exploits the doping achieved by atomic layer deposited (ALD) Al2O3 to enhance its rectifying performance. The proposed device comprises a Schottky junction that is dielectric‐doped to significantly reduce the reverse bias current. A boosted current responsivity four times higher compared to that of undoped devices is achieved, maximizing the performance for radio frequency (RF) power detectors. The application measurement results demonstrate sensitivities as low as −45 dBm, and at −30 dBm RF input power outstanding tangential responsivities up to 6.5 kV W–1, 4.3 kV W–1, and 650 V W–1 at 0.5, 1, and 2.5 GHz, respectively, while reaching linear dynamic range (DR) of over 30 dB. These are the highest reported values for 2D‐based material devices by almost two orders of magnitude. Furthermore, the DR is ≈10 dB larger compared to state‐of‐the‐art power detectors based on bulk semiconductors.

Gerard Deepak, Priti Sharma, S. Jayachitra et al.

Wearable technology can significantly impact human existence by allowing for innovative perspectives on the outside world, such as through the use of augmented reality (AR) programs. Electronic gadgets that are worn as clothing, gadgets, or even incorporated into our bodies are called wearable gadgets. While there are many prospective advantages to smartwatches, their widespread and continuous use raises several privacy problems as well as complex data protection hurdles. Among the newer areas of healthcare informatics involves cognitive computation, which uses biological as well as physical information to autonomously track an individual's emotional status in mobility settings. While effective computation technologies hold great promise for enhancing everyday life, privacy problems and challenges must be addressed before analyzing physical information. Federated knowledge is a viable option for creating high-performing algorithms while protecting people's confidentiality. We used federated training to analyze cardiac activity information that was gathered from smart wristband tracking of anxiety levels during various situations. By protecting the confidentiality of information, we were able to accomplish promising outcomes when implementing federated training in Internet of Things-based wearable physiological tracking devices.

A. I. Orlov, Il’ya A. Karpov, Vera T. Sidorova

The most common problems of electricity quality in 0.4 kV power transmission lines are voltage deviations and voltage asymmetry, which are clearly manifested at the end sections of long lines with uneven distribution of consumers by phases. The technical means of solving these problems include devices for the uniform distribution of 1-phase consumers across the phases of a 3-phase network based on electromechanical relays, static semiconductor devices and electromagnetic devices. The purpose of the article is to analyze the operation of a symmetrical electromagnetic apparatus consisting of one three-phase winding located on a common magnetic conductor. The scientific novelty consists in determining the operating conditions of a symmetrical electromagnetic apparatus, obtaining qualitative and quantitative characteristics of its operation. The materials and methods. The object of the research is a static electromagnetic apparatus that exhibits properties of voltage and current symmetry when connected to a three-phase unbalanced electric network. The methods of theoretical electrical engineering are used, in particular, the method of symmetric components, including generally accepted methods of analyzing electromagnetic processes in electric machines, methods of mathematical and computer modeling, analysis and generalization. The accepted assumptions are: sinusoidal voltages and currents; the linearity of the magnetization curve of the magnetic core material and the absence of electrical and magnetic losses in the electromagnetic apparatus. The results of the study. It is established that the effect of equalizing currents in the line and voltage symmetry when connecting an electromagnetic device containing one three-phase winding on a common magnetic circuit occurs in the case of simultaneous fulfillment of the conditions: a) the use of a three-phase magnetic circuit in which the zero-sequence magnetic flux cannot be closed in the magnetic circuit; b) connections of transformer windings according to a scheme that allows the flow of zero-sequence currents in linear conductors. The models of the 0.4 kV line with concentrated and distributed load are considered. It is shown that with an asymmetric load, the SEA currents acquire a component of zero sequence, and the linear currents are aligned compared to the load currents. The coefficient of voltage asymmetry of the zero sequence decreases practically to zero, the reverse sequence practically does not change. The effect of voltage symmetry when connecting the SEA occurs both before and after the place of its installation. A decrease in the total losses of electrical energy in the line due to the equalization of currents is demonstrated. Conclusions. An electromagnetic device containing one three-phase winding on a common magnetic circuit has the effect of balancing the voltages and currents of a three-phase power line with a zero wire, if the design of the magnetic wire does not allow the possibility of closing the magnetic flux of zero sequence within its limits, and the winding connection circuit contains a neutral outlet connected to the zero wire of the network, through which zero-sequence currents can flow. The action of the considered electromagnetic apparatus manifests itself in equalizing the line currents in magnitude and, as a result, in reducing the total losses in it. The electromagnetic device symmetrizes the voltages before and after the place of its installation, the greatest effect is manifested when placing the proposed electromagnetic device at the end of the line or at the connection point of the most powerful consumer.

Satoshi Kawakami

Moore’s Law, relating to the speed and capabilities of computers is becoming less applicable. In this ‘post-Moore’ era, a cross-disciplinary team based in the Constructive Electronics Laboratory, Kyushu University, Japan, is investigating optical computing system infrastructures, with a view to driving computing technology forward in a way that negates the need to comply with Moore’s Law. Associate Professor Satoshi Kawakami is an expert in electric circuits and computer architecture who is part of the team. The team’s expertise covers materials, devices, circuits, architectures and algorithms and is geared towards pioneering new computing technologies in the post-Moore era. Kawakami believes that the continuous improvement of computer systems with higher performance and lower power consumption/energy consumption will be essential to realise a sustainable advanced information society and wants to maximise the advantages of devices and hide their disadvantages at the system level, which will necessitate collaboration with higher system layers. Another important goal is reducing power consumption by improving the efficiency of computers. In one current project, the researchers are exploring optical computing system infrastructure for simple recurrent neural networks. The team is keen to re-examine the ideal state of optical circuits from the perspective of the entire system, including electrical memory and interfaces.

Paul Raux, Christophe Goupil, G. Verley

Following up on the recently published circuit theory for thermodynamic devices, we consider networks of Thermo-Electric Converters (TECs) in stationary non-equilibrium. Assuming constant thermoelectric properties, the integration over a finite thickness of the linear local response of the thermoelectric material yields the non-linear current-force characteristics. We show how to derive a choice of nonequilibrium conductance matrix summarizing the current-force characteristics for every available sets of currents and forces. This problem has infinitely many solutions if one considers only thermodynamic constraints. Each solution differs, among others, by the coupling between the currents. Then, we determine the current-force characteristics of the serial (respectively parallel) association of two TECs using the laws of resistance (respectively conductance) matrix addition. For TECs in series, we find current-dependent boundary conditions for each sub-device. Since currents derive from composite potentials, we also associate the derivability and continuity of these potentials at the interfaces with conditions on thermoelectric coefficients. For TECs in parallel, we discuss the possibility of loop currents that are forbidden for the serial association.

Noor Afsary, Md Koushik Alam, Zarin Tasnim Nijhum et al.

In this study, we present a novel graded index (GI) 3dB adiabatic directional coupler utilizing polymer material. Our design prioritizes both fabrication flexibility and superior performance. Through extensive numerical simulations and optimization using the R SoftCAD BPM, we demonstrate the broadband operation of our coupler across a wide spectral range. At the critical wavelength of $\mathbf{1.55}\ \boldsymbol{\mu} \mathbf{m}$, we observe low insertion loss of 0.10 dB for both transverse electric (TE) and transverse magnetic (TM) modes, bending loss of 0.0017 dB, coupling loss of 0.02 dB for both TE and TM modes, and crosstalk levels of -31.10 dB and -30.16 dB for TM and TE modes, respectively. This device holds significant promise for high-speed optical interconnects in data centers, telecommunications networks, and integrated photonic systems.

Erkin Abduraimov

The paper presents the results of a theoretical study of semiconductor circuits carried out for practical use in the development of a non-contact switching and control apparatus for starting control and under voltage protection of AC motors. According to the results of the analysis of semiconductor circuits, it is recommended to use them when creating relay devices for the automation of electrical equipment. Theoretical investigated semiconductor circuits were used in the creation of a non-contact starter of an asynchronous electric drive with protection against operation at minimal voltage drops in the network.

Yanggeun Joo, Eunji Hwang, Heemyoung Hong et al.

Abstract Memory devices are an essential part of modern electronics. Efforts to move beyond the traditional “read” and “write” of digital information in volatile and non‐volatile memory devices are leading to the rapid growth of neuromorphic technology. There is a growing demand for memory devices with continuous memory states with various retention times and greater integration density with more energy‐efficient mechanisms. Two types of memory devices (i.e., non‐volatile digital memory and neuro‐synaptic devices) have been extensively investigated with emerging materials. Among numerous materials for such memory devices, in this review, the authors focus on 2D ferroelectric materials for promising memory and synaptic devices. Three types of memory devices based on 2D ferroelectric materials are classified and discussed here: 1) ferroelectric gating of semiconducting channels, 2) active ferroelectric channels, and 3) ferroelectric tunnel junction devices. It is known that atomically thin geometry competes with ferroelectricity, which can degrade the quality of the devices based on atomically thin ferroelectric materials. Various efforts to resolve the fundamental issue with emerging 2D ferroelectric materials and how they can be used as a critical element for memory and synaptic devices are surveyed.

Het Patel, Aditya Kansara, Boppuru Rudra Prathap et al.

The exponential rise in the use of social media has resulted in a massive increase in the volume of unstructured text created. This content is presented through messages, conversations, postings, and blogs. Microblogging has become a popular way for people to share what they are thinking. Many people express their thoughts on various issues relating to their hobbies. As a result, microblogging websites have become a valuable resource for opinion mining and sentiment research. Twitter is a well-known microblogging network, with over 500 million new tweets posted daily. The goal of this study was to mine tweets for political sentiments. The extraction of tweets relating to India's well-known political leaders of different states &amp; parties in India and applying the polarity detection analysis of human behavior on the retweeted messages As a result, the sentiment classification algorithm is designed to determine whether tweets are more likely to predict the popularity of certain politicians among the general public. The subjectivity and polarity present in the tweets of political leaders are compared. The engagements of these leaders are then taken into account to determine their popularity. All these comparisons are then portrayed using data visualizations.