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

Junjie Cheng, Xiaojin Lin

As the number of electric vehicles (EV) increases, the demand for recommending the best charging location when using a large-scale charge network to charge is also increasing. A successful recommendation will utilize the user’s preference and the operational constraints of the charging network to make sure that it also takes into account the real-time operational requirements of the network. Most current papers focus on optimizing individual algorithmic components in isolation; consequently, many of these papers neglect to provide a holistic view of an integrated system. In addition, there are many operational requirements that current research does not consider, such as cold-start personalization for new users and enforcing real-time operational constraints like station availability, power capacity, maintenance windows, etc. This paper describes a deployable multi-stage recommendation system that creates a candidate list based on location and ranks preferences based on user, station and context features. The recommendation system also adds a configurable rule-based re-ranking layer to ensure that both hard constraints (i.e., charger availability and power-cap limits) and soft objectives (i.e., load balancing and operator priority) are enforced. A method for enabling mixed use between stable Bayesian and adaptive Bayesian methods was developed to provide users starting with cold-start performance that do not have adequate histories. Evaluation of this method using 100k+ real charging sessions showed that the fraction of sessions where the ground-truth station appears in the top-two recommendations (Hit@2) for the recommendation system was 0.82, representing a 37% increase in performance compared to proximity-based recommendation methods. The online deployed recommendation system has a 99th-percentile serving latency (P99) of less than 200 ms. The findings of this paper provide a framework for the implementation of operationally-relevant user-centric recommendation systems for EV services at scale.

Joshua Wheeler, Igor Zozoulenko

Abstract Conjugated organic polymers are becoming increasingly important for numerous applications due to their tunable properties, which are often optimized through doping. This study employs molecular dynamics simulations to investigate the distribution of the molecular dopant Mo(tfd–COCF3)3 in the conjugated polymer p(g42T–T), aiming to compare the theoretical findings with the experimental results of Persson et al., who used electron tomography to explore the dopant's 3D spatial distribution (Nanoscale, 2022, 14, 15404). Simulations reveal a random dopant distribution with no evidence of clustering, contrasting with Persson et al.’s observations of isolated molecules and small clusters. The discrepancy is suggested to be due to a possible difference in dopant density between the simulations and the experimental system, and potential explanations for this difference are proposed. The study highlights the need for further experimental and theoretical efforts to resolve these apparent discrepancies in dopant distributions.

Yongyu Lu, Zizheng Wang, Vagif Abdulla et al.

Abstract Liquid metals (LMs), renowned for their high conductivity and large deformability, find increasing applications including in flexible electronics and soft robotics. One critical process in these applications is the precise patterning of LMs into desired shapes. Yet, existing LM patterning techniques predominantly focus on 2D patterns due to challenges posed by the inherent fluidity and leakage of LMs. Here, we introduce an approach that bypasses these limitations, enabling the creation of complex 3D leakage‐free LM structures. This is achieved through mechanical programming of 2D magnetically immobilized LM paste formed via incorporating magnetic particles into LMs. Such composite effectively resists leakage due to the combined effect of strong magnetic inter‐attraction within the porous magnetic networks and the high surface tension of LMs, while retaining the high conductivity. Diverse freestanding magnetic LM structures, obtained upon LM solidification at ambient temperature, dynamically morph between their 2D and various 3D configurations through multiple cycles of induction heating and magnetic‐assisted reprogramming, featuring large compression resistance and self‐healing capabilities. Potential applications of these leakage‐resistant, shape‐adaptable structures are demonstrated through a helical magnetic LM antenna, which showcases its efficiency in wireless communication and energy harvesting.

Ali Kheirdoost, Maysam Haghparast, Behzad Ahmadi et al.

In this paper, the unitary condition of scattering parameters for lossless and lossy filters is investigated. The primary objective is to establish a mathematical framework that explains the limitations observed in filter amplitude response sharpness at passband edges during practical measurements. It is achieved by analytically evaluating the unitary condition using a closed form coupling matrix model. Various numerical examples are presented to demonstrate the impact of loss on the unitary condition and filter sharpness in practical scenarios. Moreover, we propose a mathematical form of the T term based on the extension to the unitary condition, serving as a gauge to quantify the rounded passband edges in filter response. This T term is related to filter design parameters and the resonators' quality factor, enabling a deeper understanding of filter performance in real-world conditions. The developed theory implication is discussed in analyzing the measurement results of three different filter in different frequency bands.

Pinwen Wang, Shouhua Han, Zhipeng Hou et al.

Abstract The rapid advancement of wearable technology has led to the growing significance of flexible sensors in medical health monitoring and motion tracking. Traditional electronic skin frequently experiences unstable sensing performance attributed to inadequate interface compatibility and uneven distribution of conductive materials. Ionic skin presents an innovative method for acquiring biological signals via ion migration; however, its biocompatibility concerns restrict its broader use. This study introduces an eco‐friendly and efficient synthetic method for the preparation of conductive elastomers utilizing deep eutectic solvents (DES) and polyvinyl alcohol (PVA). The resulting composite polymer network structure demonstrates a balance between elevated mechanical strength and high conductivity. The resultant material exhibits an electrical conductivity of 4.4 × 10⁻¹ S m⁻¹ and a tensile strain of 1200%. The attributes of this elastomer allow pressure sensors to demonstrate exceptional performance, featuring a sensitivity of 0.21 kPa⁻¹ and a wide detection range of 0–200 kPa. This research presents a novel approach for the development of high‐performance flexible sensing materials, which hold considerable application potential in areas including healthcare and motion detection.

Philip Y. Mai, Pedro H. Pereira, Lucas Andrade Alonso et al.

Quantum computation with electron spin qubits requires coherent and efficient manipulation of these spins, typically accomplished through the application of alternating magnetic or electric fields for electron spin resonance (ESR). In particular, electrical driving allows us to apply localized fields on the electrons, which benefits scale-up architectures. However, we have found that Electric Dipole Spin Resonance (EDSR) is insufficient for modeling the Rabi behavior in recent experimental studies. Therefore, we propose that the electron spin is being driven by a new method of electric spin qubit control which generalizes the spin dynamics by taking into account a quadrupolar contribution of the quantum dot: electric quadrupole spin resonance (EQSR). In this work, we explore the electric quadrupole driving of a quantum dot in silicon, specifically examining the cases of 5 and 13 electron occupancies.

Yubo Song, Subham Sahoo

High energy consumption of artificial intelligence has gained momentum worldwide, which necessitates major investments on expanding efficient and carbon-neutral generation and data center infrastructure in electric power grids. Going beyond the conventional ideation, this article unleashes innate computational abilities in the power grid network circuits itself. By programming power electronic converters (PECs) to mimic biological neurons, we sustainably transform power grids into a neural network and enable it to optimize, compute and make data-driven decisions using distributed PECs. Instead of seen merely as an energy delivery platform, this article conceptualizes a novel application for electric grid to be used as a computing asset without affecting its operation. To illustrate its computational abilities, we solve a affine transformation task in a microgrid with five PECs. By encoding the digital data into the control of PECs, our preliminary results conclude that computing using electric grids does not disturb its operation. From a scientific perspective, this work fundamentally merges energy and computing optimization theories by harnessing inherent high-dimensional computational relationships in electric grids.

Ioannis Dassios

This article introduces two new fractional operators with sine ($\sin$) and cosine ($\cos$) kernels, motivated by their fundamental role in modeling AC signals in electrical circuits. The operators are designed to improve the analysis of nonlinear components such as the memristor by transforming certain nonlinear equations into simpler linear forms, particularly in systems with memory effects.

Anoy Saha, Mona Ghassemi

The electrification of aircraft is reshaping the foundations of aerospace design by positioning electrical systems at the center of propulsion, control, and onboard functionality. This chapter provides an overview of electrical system architectures for electric and hybrid electric aircraft, highlighting both established principles and emerging design strategies. The discussion begins with the motivations for electrification, including reducing environmental impact, improving operational efficiency, and replacing complex pneumatic and hydraulic subsystems with lighter and more reliable electrical alternatives. Aircraft electrical architectures are classified into four major categories: conventional, more electric, all electric, and hybrid electric. A range of system topologies is examined, including direct current (DC), alternating current (AC), hybrid, and distributed configurations. Each is considered in terms of its effectiveness in delivering power, enabling redundancy, supporting fault isolation, and managing thermal performance. Real world examples are presented to demonstrate practical applications, with case studies drawn from the Boeing 787 Dreamliner, the Eviation Alice commuter aircraft, and NASA X57 Maxwell demonstrator. These examples illustrate the ongoing transition from incremental subsystem electrification toward fully integrated architectures that promise higher efficiency and greater sustainability.

Angel Cuadras, Victoria J. Ovejas, Herminio Martínez García

The present study examines the relationship between thermal and configurational entropy in two resistors in parallel and in series. The objective is to introduce entropy in electric circuits analysis by considering the impact of system geometry on energy conversion in the circuit. Thermal en-tropy is derived from thermodynamics, whereas configurational entropy is derived from network modelling. It is observed that the relationship between thermal entropy and configurational en-tropy varies depending on the configuration of the resistors. In parallel resistors, thermal entropy decreases with configurational entropy, while in series resistors, the opposite is true. The impli-cations of the maximum power transfer theorem and constructal law are discussed. The entropy generation for resistors at different temperatures was evaluated, and it was found that the con-sideration of resistor configurational entropy change was necessary for consistency. Furthermore, for the sake of generalization, a similar behavior was observed in time-dependent circuits, either for resistor-capacitor circuits or circuits involving degradation.

Kristina Bespalova, Glenn Ross, Sami Suihkonen et al.

Abstract Aluminum nitride (AlN) grown on vertical surfaces can be utilized for the fabrication of advanced piezoelectric microelectromechanical systems (MEMS). The in‐plane motion of the parts of a MEMS element is possible when AlN is deposited on the vertical surfaces of the moving structure. For the best device performance, AlN must have high crystal quality, uniform coverage of the vertical sidewalls, and c‐axis crystalline orientation perpendicular to the plane of a vertical surface. The impact of the surface roughness (Rq) of the vertical sidewalls formed in Si using wet and dry etching methods on the crystal quality, crystallographic orientation, and uniformity of the metalorganic chemical vapor deposited (MOCVD) AlN thin films is studied in this paper. In both cases, AlN films demonstrated full sidewall coverage and grew crystalline in the c‐axis direction. AlN films grown on vertical Si surfaces achieved using anisotropic wet etching are highly crystalline and oriented in [0001] direction, while the films grown on vertical surfaces achieved using dry etching displayed a lower level of alignment with the Si sidewalls.

Huicai Xie, Jiaxin Jiang, Lu Tian et al.

Abstract Rare earth‐based perovskites have become an attractive research interest in the field of cryogenic magnetic refrigerants due to their unique advantages in practical applications. The remarkable magnetocaloric effect (MCE) renders EuTiO3 a potential magnetic refrigerant in the liquid helium temperature range. More impressively, the tunability between antiferromagnetism (AFM) and ferromagnetism (FM) provides the feasibility of tailoring the magnetism and enhancing the magnetocaloric performance. In this study, the magnetism of EuTi0.75Al0.125Zr0.125O3 is investigated in depth through first‐principles calculations and experimental methods. Both theoretical calculations and experimental results reveal that it exhibits significant ferromagnetism due to the AFM‐FM magnetic transition promoted by the co‐substitution of Al and Zr. Lattice expansion and altered electronic interactions are responsible for the FM behavior, which leads to a significant enhancement of the MCE. With the field change of 0−1 T, the peak values of magnetic entropy change (−ΔSM), refrigerating capacity (RC), and adiabatic temperature change (ΔTad) reach 18.9 J kg−1 K−1, 77.7 J kg−1, and 7.4 K, respectively. More surprisingly, the values of maximum magnetic entropy change (−ΔSMmax) and maximum adiabatic temperature change ΔTadmax for EuTi0.75Al0.125Zr0.125O3 reach 11.4 J kg−1 K−1 and 3.7 K under the field change of 0−0.5 T, respectively. The remarkable magnetocaloric performance proves it to be a brilliant magnetic refrigerant operating near liquid helium temperature.

Vu Khac Dat, Chengyun Hong, Minh Dao Tran et al.

Abstract Multispectral photodetectors are crucial for detecting light across a wide wavelength range, serving applications requiring precise wavelength specificity and spectral imaging capabilities. However, the development of these photodetectors is hindered by several challenges, including material compatibility issues, low responsivity, the complexity of signal processing, and precise bandgap engineering. A strategy is proposed using a MoS2‐graphene photodetector to address these issues. Gate‐tunable spectral responses are achieved in a graphene photodetector by utilizing carrier transfer from MoS2 and interfacial gating effects from a SiO2/p‐doped Si substrate. Precise gate bias manipulation enables selective photocurrent capture in the range of 500–680 nm, identical to the absorption of MoS2. Furthermore, by applying a highly negative gate bias, photocurrent signals below the MoS2 bandgap, i.e., in the 680–800 nm region, are detected, significantly provoking broadband photodetection. The results highlight the versatility of gate‐tunable multispectral response, leading to an exceptional responsivity of up to 1.4  ×  105 mA W−1. Moreover, through the precise modulation of gate bias and incident wavelength, it seamlessly switches between negative and positive photocurrents. This study provides important insight into carrier photogeneration in sensitized graphene‐based multifunctional optoelectronic devices, establishing a versatile platform for detecting a broad range of photocurrents with a single detector.

Piotr Zawal, Gisya Abdi, Marlena Gryl et al.

Abstract Memristors, being prospective work‐horses of future electronics offer various types of memory (volatile and nonvolatile) along with specific computational functionalities. Further development of memristive technologies depends on the availability of suitable materials. These materials should be easily available, stable, and preferably of low toxicity. Commonly used materials are lead halide perovskites, however, they are highly toxic and unstable under ambient conditions. Therefore a novel material is developed on the basis of bismuth iodide. In reaction with butylammonium iodide, it yields a novel compound, butylammonium iodobismuthate (BABI). Here, a diffusive memristor is introduced based on this compound and evaluates its memristive and neuromorphic properties. In contrast to nonvolatile memristors, the BABI memristors exhibit diffusive dynamics, which enable them to store the information only for short periods of time. This property is utilized to mimic the short‐term synaptic plasticity described by the leaky integrate‐and‐fire model of a biological neuron. Combined with high switching uniformity and self‐rectifying behavior, these devices show high classification accuracy for MNIST handwritten datasets, paving the way for their application in neuromorphic computing systems.

J. Bhuvana, Amit Barve, Shah Pradeep Kumar et al.

Aim: Multimodal biometric recognition authenticates or identifies someone using various biometric features or modalities. Multimodal biometric systems use different biometric qualities to improve the recognition process's accuracy, security, and reliability rather than depending solely on one biometric property, such as fingerprint or facial recognition. Sensor fusion techniques can merge data from several biometric sensors, including fingerprint scanners and facial recognition cameras, to boost the accuracy and dependability of biometric authentication in the context of multimodal biometric recognition in mobile devices. The process of combining data from numerous image sensors to enhance a system's overall performance is known as image sensor fusion. Challenges: Challenges includeintegration difficulties in achieving accurate and secure multimodal biometric recognition on mobile devices. The study goal was Image sensor fusion for multimodal biometric recognition in mobile devices. Methodology: The study uses a specially made database of 450 face photos roughly 450 fingerprints.Weiner filter (WF) is used for preparing data. Battle Royale optimized with deep convolutional neural network (BRO-DCNN) is proposed to improve the overall performance of fingerprint and facial information. Findings: Accuracy, sensitivity, specificity, and precision are used to measure the effectiveness of the proposed BRO-DCNN system. Study results show that BRO-MLANN solves the many characteristics of smart cities and is an efficient approach compared to other current methods in recognition rate, 98 % accuracy, 99 % precision, 96 % specificity, and 94 % sensitivity.

Zhaoyun Chen, Jingwen Xu, Hongyu Wang et al.

Capacitively coupled plasma (CCP) tools are crucial for etching, deposition, and cleaning processes in the semiconductor industry. A comprehensive understanding of their discharge characteristics is vital for the advancement of chip processing technology. In this study, the influence of external circuitry on the breakdown process was investigated under the CF4 discharge system, with a particular focus on challenges presented by the nonlinear nature of the plasma. The results demonstrated that the external circuit significantly affects the discharge process by altering the electric field distribution as well as modifying the electron density and temperature of the plasma. By incorporating the matching circuit, stable discharge was achieved at reduced voltage levels. During breakdown, a substantial increase in the capacitance of the discharge chamber is induced by the formation of the sheath, which alters the amplitude of the electrical signal within the external circuit. The breakdown characteristics are significantly influenced by the capacitance of the matching network. Breakdowns with distinctive characteristics can be achieved by selectively choosing different capacitors. Furthermore, a shift in the CF4 discharge mode at different pressures under the external circuit model and the alteration in the discharge mode affect the electrical properties of the plasma in the matched circuit. These findings could be used to optimize the discharge of CCP and its applications, including surface treatment, material synthesis, and environmental remediation.

Akurati Prabhakar, Urbesh Sarkar, R. Ghoshal et al.

A study of the dynamics of a single cavitation bubble is fundamental for understanding a wide range of applications in science and engineering. Underwater electrical discharge is a widely used method for generating cavitation bubbles to study their inception, subsequent dynamics, and collapse. In this work, an existing underwater low-voltage discharge circuit for generating cavitation bubbles is improved further to get a wider range of maximum bubble radius. In this novel electric circuit design, the operating voltage can be varied (up to 420 V in steps of 60 V) by connecting a network of capacitors in different series-parallel combinations with the help of relay-based control. Therefore, this device can generate oscillating cavitation bubbles up to a maximum radius of 14 mm by adjusting the available discharge energy. A voltage sensor circuit is included in this design to measure the drop in voltage during the sparking event, and a correlation between the delivered energy and the potential energy of the bubble is established. The dependence of bubble radius on circuit resistance, electrode resistance, and electrode material is studied for the entire voltage range. A suitably rated semiconductor field effect transistor is used as a switch that enables the generation of bubbles of a consistent maximum radius and ensures the repeatability of the experiment. A high-speed imaging system is used to estimate the bubble radius and nucleation period, which are compared with the existing theoretical models based on empty cavity collapse. Results show that delaying the oxidation of electrodes with a protective layer influences the collapse phase and the average pressure inside the spark-generated bubble.

Z. Zhong

ABSTRACT This article reviews advanced polishing, grinding and finishing processes for challenging manufacturing applications. The topics covered are machining of advanced alloys; machining of wafers; strengths of dies after machining; grinding and polishing for wafer level packages; hybrid finishing processes; magnetorheological finishing; cooling and lubrication; dental, implant and clinical applications; grinding of metal matrix composites; machining of other brittle materials; fixed abrasive polishing; vibratory finishing; and truing, kinematics and wear of tools. Findings include that a novel three-layered ice-bonded abrasive tool was proposed to polish Ti-6Al-4V. Wafer strengths and corresponding finishing processes are challenging issues for manufacturing of microelectronics devices. The processes could significantly enhance or reduce package strengths. Burrs were minimized to zero after grinding of honeycomb using a novel wheel with small asperities on its grinding surface. Polishing of silicon substrates using a fixed abrasive pad largely shortened the polishing time. Traditionally, grinding required flood coolant, which caused various environmental problems. Recently, more companies demand reduced coolant to respond to environmental requirements. Therefore, minimum quantity of lubrication has become a novel research trend for the benefits of the environment, health and costs. Innovative approaches led to good cooling, smooth surfaces ground with low roughness and low grinding forces. Abbreviations 3PB: 3-point bending; 4PB: 4-point bending; ANN: artificial neural network; BEMRF: ball end magnetorheological finishing; CMP: chemical mechanical polishing; DTM: difficult-to-machine; EDM: electric discharge machining; EMC: epoxy mold compound; FOWLP: fan-out wafer level package; IC: integrated circuit; LCD: liquid crystal display; MAF: magnetic abrasive finishing; MRF: magnetorheological finishing; MRR: material removal rate; MMC: metal matrix composite; MQCF: minimum quantity cutting fluid; MQL: minimum quantity of lubrication; MWCNT: multi-walled carbon nanotube; RSM: response surface methodology; SQL: small-quantity cooling and lubrication; SSD: sub-surface damage; 3D: three-dimensional; TSV: through-silicon via; UV: ultraviolet; WLCSP: wafer level chip scale package; WC: tungsten carbide

Jae Hur, Dongsuk Kang, Dong‐Il Moon et al.

Abstract Cryogenic‐computing draws attention due to its variety of applications such as cloud‐computing, aerospace electronics, and quantum computing. Low temperature (e.g., 77 K) enables higher switching speed, improved reliability, and suppressed noise. Although cryogenic dynamic random‐access memory is studied, the cryogenic NAND flash is not explored intensively. Herein, a cryogenic storage memory based on the charge‐trap mechanism is reported. By removing the tunneling oxide from the conventional silicon/oxide/nitride/oxide/silicon (SONOS)‐type flash memory (therefore becoming silicon/oxide/nitride/silicon (SONS)), high‐speed and low‐power operation is aimed to be achieved while relieved from poor retention issue thanks to the cryogenic environment. The FinFET‐structured SONS memory device is demonstrated experimentally with gate length of 20–30 nm, which can achieve the retention issue (>10 years) with low voltage (≈6.5 V) and high speed (≈5 µs) operation at 77 K. To have a holistic system‐level evaluation, benchmark simulation of an interface between a host microprocessor and solid‐state‐drive is conducted, considering the refrigerator cooling cost and the heat loss via cables across two temperatures (300 and 77 K). The results show that the SONS‐type cryogenic storage system shows over 81% improvement in both latency and power, compared to the SONOS counterpart located at cryogenics.

Masud Rana Sk, Shubham Pande, Franz Müller et al.

In this article, the impact of interfacial fixed charges on the memory window (MW) of HfO2-based ferroelectric field-effect transistor (FeFET) is investigated using technology computer-aided design (TCAD) device simulations. We have considered the presence of fixed charges at the interface between the ferroelectric layer (FE) and the interlayer dielectric (IL) of FeFET with metal/ferroelectric/interlayer/Si (MFIS) gate structure. Our study indicates that the presence of fixed charges affects the polarization and corresponding depolarization field in the ferroelectric. Positive and negative interface charges can align the polarization direction. The MW degradation is observed with the increase in the fixed charge concentration (Qf).