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

Huanxin Su, Xiaobing Wang, Chao Li et al.

Abstract The development of wearable piezoelectric nanogenerator (PENG) has recently drawn extensive attention, especially in selecting lead-free piezoelectric materials with high piezoelectric coefficients. Barium Titanate (BTO) is a kind of environment-friendly piezoelectric ceramics. PENGs derived from BTO based piezo-fillers have recently attracted broad concern. However, the exploration of flexible electrodes and the application of wearable PENGs functioned with imitating tactile have usually been ignored in the pursuit of high output performance. Herein, The porous piezoelectric fillers composed of 0.82Ba(Ti0.89Sn0.11)O3-0.18(Ba0.7Ca0.3)TiO3 are prepared by a freeze-drying method, and then the polydimethylsiloxane (PDMS) is filled into the micropores of the piezoelectric ceramics, forming a distinctive 3D interconnected structure with evenly distributed inorganic piezoelectric materials. Both doping and structure modification can boost the output performance of the BTO-based PENG, from which the rational doping plays a major role in enhancing the electrical output in the current PENG system. To realize fully flexible piezoelectric nanogenerator (PENG), sliver nanowires network integrated with PDMS is adopted as the flexible electrodes, which was fabricated by the techniques combining vacuum filtration with subsequent dry transfer process. The PENG can deliver a maximum open-circuit voltage (VOC) of 39 V and short-circuit (ISC) current of 2.9 μA under a vertical force of 35 N at 2 Hz, with the maximum instantaneous power of 24.2 μW. Moreover, the device can effectively exhibit electric output signal whenever subjected to external pressing or bending stress. The output performance of the PENG at via vertical pressing stress is higher than that bending stress, which is also confirmed by COMSOL simulation. The PENG can not only be employed to harvest biomechanical energy such as digital joints movement, but also display a potential for a tactile perception. This work has established a deep association between lead-free ceramic and wearable imitated touch reception sensors by virtue of flexible PENG, which will paint a magnificent picture for flexible electronics.

Jing-Chang Li, Haibo Zhao, Yu Sun et al.

The exploitation of emerging anionic redox chemistry opens a promising pathway to boost the capacity of Li-rich layered cathodes. Lithium-rich layered sulfides are receiving unprecedented emphasis to achieve sustainable capacity based on sulfur redox chemistry. However, maintaining high capacities during cycling is still a challenge as Li+ intercalation/deintercalation is only partially reversible, especially for Li2TiS3 model materials. Here, a feasible strategy of electronic structure regulation is adopted to achieve sustainable reversible anionic redox in Li-rich layered sulfides based on the Mott-Hubbard U-Δ theory. The practicality of activating reversible sulfur redox process in Li-rich layered sulfides is verified in partial Ni substituted Li[Li1/3-2x/3NixTi2/3-x/3]S2 (0 ≤ x ≤ 0.3) system. The optimal compound (x = 0.2) delivers the largest sustained reversible capacity up to 237.3 mAh g−1 based on the cumulated cationic and anionic redox mechanism, which is about 3 times as high as the unsubstituted Li2TiS3. Furthermore, it also exhibits outstanding rate capability (76 % capacity retention at 20.0C) and excellent cycling stability (90 % capacity retention after 500 cycles), which is comparable to most of prevailing Li-rich layered oxides and sulfides. This work demonstrates the feasibility of sulfur redox chemistry and provides a fundamental understanding of regulating anionic redox activity for developing high-capacity Li-rich layered cathodes.

Shumpei Kishi, Yoshiki Sugimoto, Kunio Sakakibara et al.

A broadband right-angle transition from a rectangular waveguide (RWG) to a substrate-integrated waveguide (SIW) with a small narrow-wall width is proposed in the 270 GHz band. Generally, it is difficult to design a broadband transition from a standard RWG to an SIW with a small narrow-wall width owing to the small characteristic impedance of the SIW. In this study, wideband characteristics are obtained by placing via holes in a multilayer substrate and forming back-short structures, short stubs, and inductive pins. By varying the positions of the via holes, the two resonant frequencies are independently controlled to achieve a broad bandwidth exceeding 26%. To verify this design, back-to-back DUTs (devices under test) were fabricated and measured in the sub-terahertz band. The measured and simulated results are in good agreement. The measured insertion loss is approximately 1.1 dB at a design frequency of 275 GHz, and the measured reflection loss is less than −10 dB from 234 GHz to 308 GHz.

Amir Ali Mohammad Khani, Alireza Barati Haghverdi, Ilghar Rezaei et al.

Periodic arrays of graphene disks are leveraged to form a toxic gas detector. The operational frequency range is the THz gap. The idea stems from the middle air gap which is surrounded by graphene-spacer layers while a fully reflecting metallic surface is placed underneath. The change in the refractive index of the air gap due to the presence of some toxic gases leads to absorption deviations. Interpreting the known deviations can define a detection protocol in the THz spectrum. This work proposes a three-layer wave absorber based on the graphene patterns, TOPAS spacer, and the golden surface. Each component is modeled by the passive circuit element and the total impedance of the structure is calculated. Additionally, the impedance matching concept is investigated to predict absorption response. Furthermore, full-wave simulation is performed to compare with the circuit model approach. Based on the simulation results, a multi-band absorption response experiences considerable frequency shifts when exposed to some toxic gases including SO2, N2, NO2, O3, and CO. More importantly, the capability of being tuned via external chemical potential makes the proposed absorber an ideal basic building block for healthcare-based optical systems.

Ping Lu, Linkai Luo, Linjie Yang et al.

A novel co-designing strategy is presented for an integrated rectifying metantenna, which combines rectification, absorption and electromagnetic signal reception functionalities for simultaneous wireless information and power transfer (SWIPT). The metasurface is constructed using periodic patch units arranged in front of a compact microstrip antenna. This arrangement effectively stimulates transverse electric (TE) and transverse magnetic (TM) surface waves, which ensures not only high gain but also optimal antenna matching. Furthermore, the metasurface incorporates rectifier diodes distributed partially, significantly enhancing energy conversion efficiency. The proposed rectifying metantenna operates at 5.8 GHz (an ISM band) and achieves a maximum energy conversion efficiency of 54.6% when subjected to an input power of 0 dBm. This accomplishment is particularly noteworthy when the metantenna is integrated into devices for data communication. The proposed rectifying metantenna boasts a range of merits including high integration and multifunctionality. These inherent attributes position it as a promising candidate for advanced IoT wireless communication systems, facilitating the generation of rectified DC power while receiving RF signals without the need for power splitter and time-switching used in conventional SWIPT systems.

Xun Wang, Yahui Zhai, Zichu Zhang et al.

Abstract A chemical vapor‐liquid phase deposition and subsequent auxiliary heating method is developed to synthesize crystal CuO and CuO:Ho terrace structures. CuO terrace structures display weak ferromagnetic behavior owing to their unique crystal structure. The ferromagnetism of CuO:Ho terrace structures is significantly enhanced compared to the crystal CuO, and the values of the saturation magnetization present a parabolic trend with the increase of Ho ions doping concentrations. The magnetism of the crystal CuO:Ho terrace structures is mainly derived from the magnetic moment provided by the synergistic effect of Ho ions doping and oxygen vacancies. The saturation magnetizations and the coercivity of CuO:Ho (x = 0.88%) sample are 0.0595 emu g−1 and 90.5 Oe, respectively. The first‐principles calculations have been used to investigate the origin of ferromagnetism of the CuO:Ho terrace structures. The result of spin polarization density of states and spatial distribution of the spin density show that the origin of the ferromagnetism for CuO:Ho crystal is mainly attributed to the exchange interactions among the O 1s, Cu 2p, and Ho 4f orbits. The terrace structure of CuO:Ho samples offers a defined interface for controlling spin‐polarized states, making it suitable for exploring new spintronic phenomena.

Yuqia Ran, Yiwen Song, Long Li et al.

Abstract As Moore's law approaches its limit, achieving higher device density necessitates innovative architectures, with monolithic three‐dimensional (M3D) designs emerging as a promising solution. Although numerous top‐down fabrication methods have yielded encouraging results, they often fall short of meeting the demands for large‐scale production, ultimately hindering the development of more complex, high‐performance devices. Here, a novel approach employing all thermally evaporated thin films is presented for the bottom‐up fabrication of M3D integrated logic circuits. Utilizing p‐type tellurium (Te) and n‐type bismuth sulfide (Bi2S3) as channel materials, monolithicly stacked prototypes of inverter, NAND, NOR, AND gates, SRAM, and oscillators are successfully demonstrated. This work highlights the viability of utilizing bottom‐up synthesized thin‐film transistors (TFTs) to construct sophisticated M3D logic circuits, underscoring the significance of deposition techniques such as thermal evaporation as a highly effective approach.

Abdullah H. Alshehri, Hatameh Asgarimoghaddam, Louis‐Vincent Delumeau et al.

Abstract Metal‐insulator‐insulator‐metal (MIIM) diodes with thickness‐gradient films for the insulator layers are fabricated for the first time. Spatially varying atmospheric‐pressure chemical vapor deposition is used to deposit ZnO and Al2O3 films with orthogonal gradient directions, producing 414 MIIM diodes with 414 different ZnO/Al2O3 film‐thickness combinations on a single substrate for combinatorial and high‐throughput optimization. The nm‐scale ZnO/Al2O3 films are printed in only 2 min and the entire device fabrication takes 7 h, which is much less than conventional approaches for investigating many insulator‐thickness combinations. Rapid identification of the optimal thickness combination is demonstrated; high‐performance diodes (asymmetry = 227, nonlinearity = 13.1, and responsivity = 12 A/W) are observed when a trap‐assisted tunneling mechanism is dominant for insulator thicknesses of 3.4–4.4 nm (ZnO) and 7.4 nm (Al2O3).

Bhanu Priyanka Valluri, Nitin Sharma

Researchers are drawn to Wireless Sensor Networks (WSNs) due to its versatility and possible use cases in a variety of fields, including target tracking and identification environmental sensing, industrial process tracking, and tactical systems. Recently, there has been a lot of focus on the particular issues that arise from implementing routing in sensor networks as opposed to the more conventional data routing in wireless connections. Due to the importance of energy conservation in the design of WSNs, numerous protocols for routing, power management, and data transmission have been developed for these networks. When it comes to environmental monitoring, traffic monitoring, etc., routing in WSNs is crucial. The primary objective of this study is to analyse routing issues and to analyse routing-related optimization issues. Features pertaining to routing issues like energy consumption, security, speed, and dependability are explored later. Attention has been paid to the routing protocols, which might vary by use case and network design. In this study, a comprehensive review is performed on the cutting-edge approaches to routing in WSNs. A brief introduction to WSNs and a discussion of the obstacles that routing protocols must overcome throughout their creation before moving on to a thorough examination of the various routing approaches now in use is considered. The comparative analysis is performed different routing techniques like Energy-Aware Routing for Software-Defined Multihop Wireless Sensor Networks (EAR-SDMWSN), DORA: A Destination-Oriented Routing Algorithm for Energy-Balanced Wireless Sensor Networks (DORA) and Energy Proficient Load Balancing Routing Scheme for Wireless Sensor Networks (EP-LBR). The benefits and drawbacks of each routing method, with an emphasis on performance is also performed.

Samira BEDIAR, Abdelkader HARROUZ, Djamel BELATRACHE

In isolated sites, the extension of the electricity network requires a very high capital cost. For agriculture work, irrigation is a necessity. A possible solution is using renewable energy sources like solar power, which is environmentally friendly and available for free. This paper presents the design and simulation of a photovoltaic water pumping system for irrigation of a farm located at a place named Tsabit in Adrar southwest Algeria. A detailed approach for the design of an optimized PV water pumping system based on real water usage data is proposed. Besides, system design work and performance assessment were carried out based on hourly climatic conditions. PV SYST software is used to carry out this work. A comparison was also made between two water pumping systems with and without use of a sun tracker. From the obtained results, the use of this kind of system could have an important contribution in the social and economic development of a country, especially in the presence of a sun tracker device, where we recorded more efficiency.

F. Monaghan, A. Martinez, J. Evans et al.

In this paper, we present a monolithically integrated temperature sensor for a 4H-SiC JFET. This uses a lateral resistor formed by the P+ gate implant. The sensor resistance is dependent on the number of ionized dopants, which increases with temperature. Drift-diffusion simulations considering device self-heating have been carried out, which show the JFET exhibits a breakdown voltage of 1480 V and a nominal threshold voltage (Vth) of −4.3 V. We show that the sensor has a high degree of linearity (R2) of 0.996 between 25–150∘C. Breakdown voltage of the JFET with the integrated sensor is found to reduce as the spacing (S) between the gate junction, the adjacent floating guard ring (FGR) and the sensor junction increases. However, it is found that a large variation in sensor current (ΔIsens) is experienced in the off-state if S is small. An optimum value of S = 0.95 µm was found to maintain 90% of the JFET breakdown voltage, whilst only exhibiting ΔIsens= 3.4%. The impact of contact resistance to the total sensor resistance is ≤1%. In addition, the sensor robustness during switch-off is good, due to the high doping in the P+ layer. The proposed sensor can be integrated into 4H-SiC JFET without any modification of existing process flows, or additional mask layers to provide real-time temperature monitoring with high accuracy.

Hiroaki Komatsu, Norika Hosoda, Toshiya Kounoue et al.

Abstract Health monitoring using wearable artificial intelligence (AI) sensors with sensing and cognitive capabilities has garnered significant attention. The development of self‐contained AI sensors that can operate with low power consumption, akin to the human brain, is necessary. Physical reservoir computing (PRC), which mimics the human brain using physical phenomena, offers a low‐power consumption architecture. Nevertheless, creating a flexible and easily disposable sensors using PRC capable of processing optical signals with sub‐second response times suitable for biological signals presents a challenge. In this study, a disposable and flexible paper‐based optoelectronic synaptic devices are designed, which are composed of nanocellulose and ZnO nanoparticles, for PRC. This device exhibits synaptic photocurrent in response to optical input. To assess its performance, a classification and time‐series forecasting tasks are conducted. The memory capacity of short‐term memory task, indicating the device's ability to store past information, is 1.8. The device can recognize handwritten digits with an accuracy of 88%. These results highlight the potential of the device for PRC. In addition, subjecting the device to 1000 rounds of bending do not affect its accuracy. Furthermore, the device burn in a few seconds, much like regular office paper, demonstrating its disposability.

M. Argyelan, Z. Deng, O. Ousdal et al.

Neurostimulation is a mainstream treatment option for major depression. Neuromodulation techniques apply repetitive magnetic or electrical stimulation to some neural target but significantly differ in their invasiveness, spatial selectivity, mechanism of action, and efficacy. Despite these differences, recent analyses of transcranial magnetic stimulation (TMS) and deep brain stimulation (DBS)-treated individuals converged on a common neural network that might have a causal role in treatment response. We set out to investigate if the neuronal underpinnings of electroconvulsive therapy (ECT) are similarly associated with this causal depression network (CDN). Our aim here is to provide a comprehensive analysis in three cohorts of patients segregated by electrode placement (N = 246 with right unilateral, 79 with bitemporal, and 61 with mixed) who underwent ECT. We conducted a data-driven, unsupervised multivariate neuroimaging analysis Principal Component Analysis (PCA) of the cortical and subcortical volume changes and electric field (EF) distribution to explore changes within the CDN associated with antidepressant outcomes. Despite the different treatment modalities (ECT vs TMS and DBS) and methodological approaches (structural vs functional networks), we found a highly similar pattern of change within the CDN in the three cohorts of patients (spatial similarity across 85 regions: r = 0.65, 0.58, 0.40, df = 83). Most importantly, the expression of this pattern correlated with clinical outcomes (t = −2.35, p = 0.019). This evidence further supports that treatment interventions converge on a CDN in depression. Optimizing modulation of this network could serve to improve the outcome of neurostimulation in depression.

N. Sobolev

A spectre is haunting the globe—the spectre of a revolution in electronic devices. The inevitability of this revolution is dictated by the emergence of new paradigms of electronics, such as neuromorphic computing, which cannot be implemented on existing hardware. One of the key enablers of the new paradigms is the memristor (resistor with memory). The latter is often based on the electrical resistive switching (RS) phenomenon. However, the memristive systems include also capacitive and inductive elements, namely, capacitors and inductors whose properties depend on the state and history of the system. Besides the classical resistive memories, quantum effects may open up new horizons for the implementation of new information storage and processing capabilities, e.g., in superconducting quantum circuits, quantum photonic devices, or using tunnelling and exciton-polariton interaction processes. The respective devices may find application in neuromorphic systems to simulate learning, adaptive, and spontaneous behavior. The symposium “Resistive switching: physics, devices and applications” held in the framework of the 16th International Conference on Nanostructured Materials (NANO 2022, 6–10 June 2022, Seville, Spain) was dedicated to all aspects of resistive switching from theory and modelling through novel materials to circuit elements and system design. The main RS-related hot topics covered by the articles are as follows: • Resistive switching mechanisms • Theory and modelling • Novel memory materials • Experimental techniques • Electrical transport • Memory cells and arrays • Circuit elements with memory • Neural networks, bio-inspired electronics, and bio-interfaces • Quantum memristive systems • Memcomputing • Unconventional computing hardware • Information security hardware The program of the symposium comprised a total of 10 invited and 33 oral talks, as well as 14 poster presentations. The presenters came from 16 countries located on 4 continents: Asia, Europe, and North and South America. Seven presentations have been selected for publication in a dedicated Special Section of physica status solidi (a). Maldonado et al. (article no. 2200520) address the most important hurdle to progress in the development of resistive memories which is the so-called cycle-to-cycle variability which is inherently rooted in the resistive switching mechanism behind the operational principle of these devices. To achieve the whole picture, variability must be assessed from different viewpoints going from the experimental characterization to the adequation of modelling and simulation techniques. The authors show how this variability can be extracted and analyzed for such main parameters of resistive switching as the SET and RESET voltages/currents and how it depends on the methodology used and experimental conditions. The following three papers treat the modelling and simulation of memristive structures. Busygin et al. (article no. 2200478) developed a one-dimensional mathematical model of memristor switching that includes a full physical model of steady-state heat and mass transfer processes. The model considers ions and vacancies generation, recombination and drift in an electric field in the metal-oxide-metal structure with a dominant charge transport mechanism of electron tunnel hopping through vacancies. Catarina Dias and João Ventura (article no. 2200730) applied numerical modelling to study the influence of metal oxide layer thickness and defects on resistive switching behavior. The Random Circuit Breaker model was implemented and the dependence of the forming, set and reset voltages on the oxide thickness and defect percentage was compared with experimental data. Sparvoli et al. (article no. 2200591) simulated the behavior of neuronal membranes based on graphene oxide memristors and validated the operation of an RC circuit as a possible tool for the analysis of memristor devices. The important effect of training pulse parameters on the synaptic plasticity of a ZrO2(Y)-based memristive device was investigated by Koryazhkina et al. (article no. 2200742). The observed result was explained in terms of the work required to change the resistive state. Moreover, the ZrO2(Y)-based memristive device under study exhibited distinguishable potentiation and depression for at least 1000 cycles. The last two articles describe memristors based on unusual materials. The Pershin group (article no. 2200643) took advantage of the fact that when a drop of Glenlivet whisky evaporates, it leaves behind a uniform deposit. The authors utilized this finding in the fabrication of electrochemical metallization memory (ECM) cells. The top (Ag) and bottom (Co) electrodes were separated by a layer of Glenlivet whisky deposit (an insulator). The device response was typical of ECM cells that involve threshold-type switching, pinched hysteresis loops, and a large difference between the highand low-resistance states. The surface coating process results in a biodegradable insulating layer, which may facilitate the recovery of recyclable materials at the end of the device’s use. N. A. Sobolev Departamento de Física and i3N Universidade de Aveiro Portugal E-mail: sobolev@ua.pt

Aiym Rakhmetova, Ayaulym Belgibayeva, Gulnur Kalimuldina et al.

A novel approach to develop a low-temperature lithium-ion battery (LIB) based on tin selenide (SnSe) and carbon (C) nanofibers as the active electrode material has been successfully achieved. The SnSe@C nanofiber anode exhibited excellent electrochemical properties, such as high capacity and good rate capability. The anode maintained a consistent charge capacity of ∼923 mAh g−1 at a current rate of 0.1 A g−1 over 100 cycles at room temperature. Furthermore, investigated for the first time at low temperatures, the SnSe@C nanofiber anode exhibited superior capacity (∼430 mAh g−1 at −20 °C) compared to conventional graphite electrode (∼25 mAh g−1 at −20 °C). The proposed SnSe@C nanofiber anode demonstrated a great potential to be applied for developing next-generation LIBs with improved low-temperature performance.

Hongyi Dou, Markus Hellenbrand, Ming Xiao et al.

Abstract Defect engineering in valence change memories aimed at tuning the concentration and transport of oxygen vacancies are studied extensively, however mostly focusing on contribution from individual extended defects such as single dislocations and grain boundaries. In this work, the impact of engineering large numbers of grain boundaries on resistive switching mechanisms and performances is investigated. Three different grain morphologies, that is, “random network,” “columnar scaffold,” and “island‐like,” are realized in CeO2 thin films. The devices with the three grain morphologies demonstrate vastly different resistive switching behaviors. The best overall resistive switching performance is shown in the devices with “columnar scaffold” morphology, where the vertical grain boundaries extending through the film facilitate the generation of oxygen vacancies as well as their migration under external bias. The observation of both interfacial and filamentary switching modes only in the devices with a “columnar scaffold” morphology further confirms the contribution from grain boundaries. In contrast, the “random network” or “island‐like” structures result in excessive or insufficient oxygen vacancy concentration migration paths. The research provides design guidelines for grain boundary engineering of oxide‐based resistive switching materials to tune the resistive switching performances for memory and neuromorphic computing applications.

Hamid BENTARZI, Abderrahmane OUADI, Abdelkader ZITOUNI

This paper focuses on discussing an energy management system (EMS) for a smart microgrid integrating multiple renewable sources. The task of the EMS is to efficiently balance power generation and consumption by controlling various energy sources, including photovoltaic systems, energy storage units, engine generator set and the utility grid. An EMS optimizes power flow between the microgrid components and keeps the micro-grid stable, by using different control strategies. In this microgrid, the PV system serves as the primary energy source, while the other sources of electrical energy act as backups. The energy management system prioritizes supplying load demand from either the PV system or the other sources, with load shedding during peak hours if the supplied energy is insufficient. The approaches based on StateMachine and StateFlow are discussed in this paper for enhancing the energy management system's performance.

A. Toropov

Introduction. The article considers the issues of operation of circulating pumps of autonomous heat supply systems when the heating circuit is filled with antifreezing coolants. It is possible to remotely start up a heating system cooled down to –15 °С. Ethylene glycol and propylene glycol antifreeze have been studied as antifreeze carriers. Flow-rate characteristics, power efficiency coefficients are studied for “wet rotor” circulation pumps in versions of electric motors of asynchronous type with constant rotor speed and energy-saving pumps on permanent magnets. Materials and methods. The research was carried out on test stands. Wall-mounted gas boilers and electric boilers witha rated capacity up to 24 kW were used as heat generators. Circulation motors, control hydraulic valves, part of the pipes with a length of 6 meters were located in a separate freezer. The pumps and parts of the heating circuit were kept at subzero temperatures for 2 hours before the system was started up Results. Pressure and flow characteristics of two types of pumps, energy efficiency coefficients were obtained, comparisons with water coolant are provided, the influence of electric network voltage on the investigated parameters was determined. Conclusions. The research has shown the possibility of starting circulating pumps in a refrigerated condition with a temperature of –15 °С. Remote start of the cooled heating system with circulation circuit filling with antifreeze when using hydrocarbon fuel boilers is not possible. Operation of heating systems with non-freezing coolants in the operation temperature ranges of 20–80 °C requires changing in settings of the combustion process and a significant increase inthe circulation pump head in comparison with the coolant water.

Kenichiro Sano, Shuntaro Horiuchi, Taku Noda

J. Dittmann, Cara-Nastasja Behrendt, B. Ponick

This article describes a method to predict the voltage distribution in the stator winding of an electrical machine with profile conductors (hairpins). The method allows the identification of spots with high potential differences where high stresses in the insulation system occur. It can be used in the design phase of the machine to design a specific insulation system or to insulate the conductors with high differential potential individually. The parasitic and partially frequency-dependent parameters used in the method are based on the geometric parameters of the winding i.e. on its conductordimensions, windinglayout and their materials. They are subsequently combined into a distributed equivalent circuit network. The resulting network is solved in the frequency domain using a modified nodal analysis. An ideal or measured input voltage pulse is applied to the system and the transient nonlinear electric potentials of the individual conductors are determined, yielding responses as function of time.