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

MD Rakibur Rahman, Satheesh Bojja Venkatakrishnan, John L. Volakis

Future radios face the challenge of delivering faster data rates while efficiently utilizing the limited and regulated electromagnetic spectrum. In this context, broadband spectrum access in-band full-duplex (IBFD) operation using a simultaneous transmit and receive (STAR) radio architecture is attractive. These radios&#x0027; features are not only enhancing throughput but also improving multi-user access. However, in designing STAR radios, it is necessary to suppress self-interference (SI) from the transmitted and received signals. The challenge of suppressing this interference becomes even more severe for wideband operation due to the dynamic and time-varying nature of wireless channels. In fact, the SI leakage at the receiver can be up to 10 billion (<inline-formula><tex-math notation="LaTeX">$10^{9}$</tex-math></inline-formula>) times greater in magnitude than the intended signal power. This necessitates a multi-stage cancellation approach. To address this, we propose a custom-designed and cost-effective multi-stage SI cancellation strategy. The first two stages incorporate passive components to achieve high isolation across a wide bandwidth. Our innovative RF-SIC (self-interference cancellation) filter, combined with a multi-antenna setup, provides <inline-formula><tex-math notation="LaTeX">$&gt;60\;\text{dB}$</tex-math></inline-formula> of isolation in the analog domain across a contiguous 1 GHz bandwidth from 2&#x2013;3 GHz. Past STAR radios delivered up to 500 MHz bandwidths. Therefore, this is the first paper to present a RF-SIC filter that works across 1 GHz. The paper is focused on the RF-SIC filter using a microstrip fabrication process. Also, in contrast to past FIR filters, the proposed one doesn&#x0027;t employ discrete components. Instead, it uses the impedance and delay of the shunt section as control parameters.

Hanna Świątek, Sylwia Gutowska, Michał J. Winiarski et al.

Abstract The synthesis and characterization of a new compound Mg4Pd7As6, which is found to be a superconductor with Tc = 5.45 K is reported. Powder X‐ray diffraction confirms the U4Re7Si6 structure (space group Im‐3m, no. 229) with the lattice parameter a = 8.2572(1) Å. Magnetization, specific heat, and electrical resistivity measurements indicate that it is a moderate‐coupling (λ = 0.72) type‐II superconductor. The electronic and phonon structures are calculated, highlighting the importance of antibonding Pd–As interactions in determining the properties of this material. The calculated electron–phonon coupling parameter λ = 0.76 agrees very well with the experimental finding, which confirms the conventional pairing mechanism in Mg4Pd7As6.

Suleiman Aliyu Babale , Sani Halliru Lawan, Md Fawzul Kabir Badhan et al.

This paper presents a compact beamforming network designed to achieve broadside radiation when integrated with a microstrip antenna array. The steering mechanism employs a planar Butler Matrix (BM), which is composed of compact 90° 3 dB microstrip couplers. Antenna elements are spaced at 0.3Ȝ, allowing intentional overlap that shifts the main beam away from broadside, thereby producing a prominent grating lobe in the broadside direction. Both full-wave electromagnetic simulations and experimental measurements confirm that the design delivers broadside coverage, high gain, and a compact form factor. The prototype exhibits good agreement between simulated and measured S-parameters, validating effective impedance matching and beam steering performance.

Sheli Muzafe Reiss, Salma Khaldi, Omer Shoseyov et al.

Abstract As data storage demands increase, the need for highly dense memory solutions becomes crucial. Magnetic nanostructures offer a pathway to achieve dense memory devices, but standard magnetic memory bit sizes are limited to over 50 nm due to fundamental ferromagnetic properties. In this study, a 10 nm chiral magnetic memory device is introduced using a self‐assembly gold nano‐floret device. The device is composed of a SiGe nanowire with a selectively decorated gold metallic shell deposited at the nanowire tip. The tip with the thiol linkers functions as a weak ferromagnet particle that is stabilized by the chiral ligands. The nano‐floret functions as a high geometrical aspect ratio electrode measuring 30–60 nm in diameter and 1–10 microns in length. The mechanical contact of the Au with a counter Ti electrode forms a nanojunction that can be probed electrically, bridging the gap between the nanoscale and the microscale. In this junction, chiral molecules are adsorbed together with 10 nm super‐paramagnetic iron oxide nanoparticles (SPIONs) forming a magnetic memory device. The same device provides valuable insights into the chiral monolayer properties on selected metal surfaces demonstrating a new approach for characterizing the molecular tilt angle in monolayers of chiral molecules.

Ch Gangadhar, P Pavithra Roy, R. Dinesh Kumar et al.

Older people face serious issues with unintentional collisions that result in healthcare admissions and fatalities. Since numerous accidents happen quickly, it might be difficult to identify crashes in context. Enhancing the quality of services for older people requires the development of a computerized surveillance network that can anticipate accidents before occur, offer protection throughout the incident, and send out remote warnings following an accident. This research suggested a wearing surveillance system that seeks to detect accidents at the onset and lineage, triggering an alarm to reduce damages caused by accidents and sending out an external alert when the human body hits the hard surface. Meanwhile, the research's offsite evaluation of a combined structure utilizing the Random Forest technique (RF), Supporting Vectors Machines (SVM), and available information were used to illustrate this idea. The suggested method employed RF to reliably retrieve features from speedometer and inertial facts, while SVM provides an estimator and classification-capable method. Each module in the unique category-based composite structure is recognized at a certain level. The suggested strategy outperformed modern fall identification techniques when tested using the labeled KFall database, achieving average precision of 95 percent, 96 percent, as well as 98 percent for Non-Falls, Pre-Falls, as well as detectable fall incidents, correspondingly. The whole assessment proved the algorithmic learning structure's efficacy. Older people's standard of existence will increase, and accidents will be avoided because of such smart tracking devices.

Ansgar Jüngel, Tuan Tung Nguyen

The existence of global weak solutions to a partial-differential-algebraic system is proved. The system consists of the drift-diffusion equations for the electron, hole, and oxide vacancy densities in a memristor device, the Poisson equation for the electric potential, and the differential-algebraic equations for an electric network. The memristor device is modeled by a two-dimensional bounded domain, and mixed Dirichlet-Neumann boundary conditions for the electron and hole densities as well as the potential are imposed. The coupling is realized via the total current through the memristor terminal and the network node potentials at the terminals. The network equations are decomposed in a differential and an algebraic part. The existence proof is based on the Leray-Schauder fixed-point theorem, a priori estimates coming from the free energy inequality, and a logarithmic-type Gagliardo-Nirenberg inequality. It is shown, under suitable assumptions, that the solutions are bounded and strictly positive.

Jing-Yu Lin, Sai-Wai Wong, Lu Qian et al.

In this paper, the design methodology and implementation of single-band and multiple-band elliptic function bandpass filters (BPFs) are presented, based on the concept of bandstop resonator (BSR) sections. One or more single-mode and multiple-mode BSRs can be dangled from a non-resonant node. Each BSR can generate one reflection zeroes (RZ) and one transmission zeroes (TZ). Multiple BSR sections are used to flexibly and independently control the location and bandwidth of the stop bands and therefore the same of the passbands. The method to design single- and multiple-band elliptic function BPFs has been detailed using a number of examples based on waveguide technology. For proof of concept, a 6th-order single-band BPF with six BSR &#x003D; 2 sections and a 3^rd-order dual-band BPF using three BSR &#x003D; 3 sections are designed and fabricated monolithically using a selective-laser-melting (SLM) 3-D printing technique. Excellent agreement between simulated and measured results verifies the proposed design methodology and its versatility as well as the additive-manufacture approach.

Surjeet Dalal, Ajay Kumar, Umesh Kumar Lilhore et al.

Businesses that want to benefit from cloud computing must choose a Cloud Service Provider (CSP). Cost, performance, Reliability, security, and SLAs must be evaluated during the decision process. CSP assessment is tough because of uncertainties and erroneous data. Fuzzy logic and the firefly optimization technique have been proposed in this paper to achieve optimal results based on diverse components. The proposed methodology uses consumer, service provider, and public reviews based on the three elements. These components' ratings can be used to analyze efficiency. Simple fuzzy logic is inferior to optimized fuzzy logic, according to experiments. The Firefly Optimized Fuzzy DSS is compared against non-optimized fuzzy decision-making systems and standard optimization methods. The results show that the proposed model is better for selecting the best CSP based on many parameters and managing assessment uncertainty. Fuzzy logic and optimization methods provide more nuanced and precise decision-making that accounts for subjective assessments and confusing facts. Businesses can make informed choices and ensure their CSP needs are satisfied with the approach. Finally, the Firefly Optimized Fuzzy Decision Support System offers a new perspective on cloud service provider selection by merging fuzzy logic with optimization. The system's ability to handle poor evaluations and ambiguity makes it ideal for CSP selection's complex decision-making process. This paper helps build decision support systems for choosing a cloud service provider and has substantial implications for firms seeking successful cloud computing solutions. This research work's conclusions have major implications for corporations and organizations searching for the finest cloud service providers. CSP-related real-world datasets are tested experimentally.

Arun Kumar, Aniello Pelella, Kimberly Intonti et al.

Abstract The family of 2D chalcogenide semiconductors has been growing rapidly. Metal monochalcogenides, for instance, can enable new possibilities in functional electronics and optoelectronics. A Gallium Selenide (GaSe) thin flake is used to fabricate a back gated field effect transistor (FET) with n‐type conduction behavior and wide hysteresis at the ambient conditions. The device shows high mobility up to 28 cm2 V−1 s−1 with Ion/Ioff ratio over 103. Under the laser exposure, the device shows a decrease in the threshold voltage and a left‐shift of the transfer characteristic with a slight increase in the current. The transfer characteristic exhibits a hysteretic behavior with hysteresis width linearly dependent on the applied gate voltage. Moreover, the GaSe‐based FET shows a photo response with a photoresponsivity of 475 mAW−1 and detectivity of 4.6 × 1012 Jones. The photocurrent rise and decay times are 0.1 and 1.3 s, respectively. Furthermore, the GaSe FET device can be used as a performant memory device with well separated states and memory window enhanced by the laser exposure, confirming an optoelectronic memory class.

Jyotisman Rath, Brindha Ramasubramanian, Seeram Ramakrishna et al.

Metal-air batteries (MABs) have emerged as a promising contender in the quest for alternative energy storage technologies, rivalling the widespread utilization of lithium-ion batteries (LIBs). Their comparable theoretical energy density to gasoline, reaching ∼12,000 Wh/kg, has sparked great interest. However, the practical implementation of MABs has been hindered by limitations associated with metal anodes, including volume expansion and unwanted side reactions. Surprisingly, the exploration of metalloid-air batteries (MLAB) remains largely unexplored. This comprehensive review aims to shed light on the potential of MLABs as a novel alternative battery technology. This technology employs metalloids in their elemental form or as compounds/alloys. Elemental metalloids, such as Silicon and Germanium, when used as anodes in combination with alkaline or Ionic liquid electrolytes, have showcased remarkable performance, surpassing their metallic counterparts in energy density, corrosiveness, and discharge time, among other critical factors. Moreover, this review delves into the discussion of Borides and Silicides, compounds of elemental Boron and Silicon, respectively, as anode materials for air batteries. Furthermore, diverse metalloid composites and computational studies exploring innovative configurations have also been examined and discussed, paving the way for future advancements in MLABs.

Guo Yuanda

Adaptive genetic algorithm is one of the classic algorithms to solve multi-objective optimization problems. In order to make the convergence set to the Pareto boundary more uniform, this article improves how to compare multiple distances in the algorithm, introduces the concept of comparing the difference between single distances, and uses the adaptive and mutation of crossover operators and the minimum distance filtering mechanism. An improved NSGA-II adaptive algorithm is proposed. Among other things, in the machine learning system model, the environment refers to an external source of information, which provides research-related information. This study proved that learning requires systematic organization, similar to short-term memory in information processing models. Find the external environment, then use the methods of thinking analysis, integration, comparison and induction to obtain knowledge, and store the knowledge in a scientific way. With the rapid development of knowledge in modern society, on the basis of the development of English text analysis technology and network technology, the reform of China's education system has reached a new level. Reforming modern teaching methods is an important part of education reform. More and more educators are considering analyzing English texts as one of the important tools to reform teaching methods and improve teaching effects. Among other things, based on the B/S model development technology, the teaching system is researched using production theories and methods, and the teaching system is actually being tested, developed and applied. By comparing the effects of computer network teaching methods and traditional teaching methods, the feasibility and effectiveness of the network teaching system are determined.

Xinxin Wang, Ilia Valov, Huanglong Li

Abstract Self‐attention mechanism is critically central to the state‐of‐the‐art transformer models. Because the standard full self‐attention has quadratic complexity with respect to the input's length L, resulting in prohibitively large memory for very long sequences, sparse self‐attention enabled by random projection (RP)‐based locality‐sensitive hashing (LSH) has recently been proposed to reduce the complexity to O(L log L). However, in current digital computing hardware with a von Neumann architecture, RP, which is essentially a matrix multiplication operation, incurs unavoidable time and energy‐consuming data shuttling between off‐chip memory and processing units. In addition, it is known that digital computers simply cannot generate provably random numbers. With the emerging analog memristive technology, it is shown that it is feasible to harness the intrinsic device‐to‐device variability in the memristor crossbar array for implementing the RP matrix and perform RP‐LSH computation in memory. On this basis, sequence prediction tasks are performed with a sparse self‐attention‐based Transformer in a hybrid software‐hardware approach, achieving a testing accuracy over 70% with much less computational complexity. By further harnessing the cycle‐to‐cycle variability for multi‐round hashing, 12% increase in the testing accuracy is demonstrated. This work extends the range of applications of memristor crossbar arrays to the state‐of‐the‐art large language models (LLMs).

Samantha T. Jaszewski, Shelby S. Fields, Sebastian Calderon et al.

Abstract Biaxial stress is identified to play an important role in the polar orthorhombic phase stability in hafnium oxide‐based ferroelectric thin films. However, the stress state during various stages of wake‐up has not yet been quantified. In this work, the stress evolution with field cycling in hafnium zirconium oxide capacitors is evaluated. The remanent polarization of a 20 nm thick hafnium zirconium oxide thin film increases from 9.80 to 15.0 µC cm−2 following 106 field cycles. This increase in remanent polarization is accompanied by a decrease in relative permittivity that indicates that a phase transformation has occurred. The presence of a phase transformation is supported by nano‐Fourier transform infrared spectroscopy measurements and scanning transmission electron microscopy that show an increase in ferroelectric phase content following wake‐up. The stress of individual devices field cycled between pristine and 106 cycles is quantified using the sin2(ψ) technique, and the biaxial stress is observed to decrease from 4.3 ± 0.2 to 3.2 ± 0.3 GPa. The decrease in stress is attributed, in part, to a phase transformation from the antipolar Pbca phase to the ferroelectric Pca21 phase. This work provides new insight into the mechanisms controlling and/or accompanying polarization wake‐up in hafnium oxide‐based ferroelectrics.

José Carlos Pérez‐Martínez, Diego Martín‐Martín, Belén Arredondo et al.

Abstract Halide perovskites (HPs) are promising materials for memristor devices because of their unique characteristics. In this study, nonvolatile resistive switching memory devices based on thick MAPbI3 perovskite (800 nm) films with structure FTO/MAPbI3/polymethyl methacrylate (PMMA)/Ag are presented. Reproducible and reliable bipolar switching characteristics are demonstrated with an ultra‐low operating voltage (−0.1 V), high ON/OFF ratio (106), endurance (>2 × 103 times) and a record retention time (>105 s). The I–V curve of the first cycle exhibits self‐formed conductive filaments. These are attributed to the presence of metallic Pb resulting from an excess of PbI2 in the perovskite film. The subsequent activation process involves the formation of conductive filaments, consisting of either iodide vacancies or migrated charged metals. Numerical simulations are then carried out to understand the nature of these conductive filaments and the role of the internal electric field in the migration of iodide ions, iodide vacancies, and Ag cations. Finally, an exhaustive model is proposed that explains the set and reset processes governing the first voltage cycle and the steady state, at different voltage ranges. In summary, this work offers a novel and thorough perspective of the complete resistive switching (RS) behavior in a MAPbI3/buffer/Ag memristor, supported by numerical simulations.

R. Karthi Kumar, S.P. Vimal

In today's computer world, a lot of real-time applications require rapid processing units. Arithmetic Logic Units (ALU) and Multiply-Accumulate (MAC) are the fundamental parts of these circuits and are necessary for their effective and rapid operation. The most significant prevalent part of digital signal processing devices is multipliers. The multiplier, adder, and registers need to be changed in order to maintain accuracy and increase execution speed, which will improve the performance of the ALU and MAC. The development of greater multipliers is being given priority for application in processors because of the increasing constraints on latency. To accelerate multiplication, it is essential to develop quicker multipliers. Vedic multipliers are preferred over different current expansions due to their low power consumption, fast operation, and efficient use of space. Vedic mathematics-based algorithms are often utilized to build quick, low-power multipliers. In addition to simulation results, this section covers the four sutras of Vedic mathematics: Urdhva Tiryakbhyam, Ekadhikena Purvena, Ekanyunena Purvena, and Nikhilam. Vedic multipliers are also compared to a variety of modern multipliers, including booth, Wallace, and array multipliers. All of the sutras are evaluated according to area, speed, power, propagation delay, and mean relative error (MRE) in the current research. The results of the study will be applied in the biomedical field.

Waldemar Bauer, Marta Zagorowska, Jerzy Baranowski

Fault monitoring and diagnostics are important to ensure reliability of electric motors. Efficient algorithms for fault detection improve reliability, yet development of cost-effective and reliable classifiers for diagnostics of equipment is challenging, in particular due to unavailability of well-balanced datasets, with signals from properly functioning equipment and those from faulty equipment. Thus, we propose to use a Bayesian neural network to detect and classify faults in electric motors, given its efficacy with imbalanced training data. The performance of the proposed network is demonstrated on real life signals, and a robustness analysis of the proposed solution is provided.

Prashant Madhukar Yawalkar, Deepak Narayan Paithankar, Abhijeet Rajendra Pabale et al.

An integrated identity is a centralized identifier that makes it possible for customers to get access to a variety of business services from a single network. The risks and assaults include identity leaks, centralized management, auditing restrictions, and lengthy breach investigation procedures. The article presents a technique for creating a blockchain-based, integrated identification system in a marketplace by automating and decentralizing the creation and auditing of strong and secure attributes. When individuals engage in market transactions, they act as nodes in a distributed blockchain network, contributing to the development of federated identities. Using a single federated identity, members of this network are able to use any of the participating companies' services. In this, IoT sensors and wearables can automatically log real-time data for you while identifying patterns and flagging problems. The total transparency of all blockchain transactions provides participants the ability to see which services they're using and their users the ability to track the usage of their identities. To test the proposed architecture, implementation done on a public blockchain and a permissioned blockchain (Ethereum and Hyperledger Fabric).

Divya Singh, Sajal K. Paul

This work presents a new active block called the differential current conveyor cascaded transconductance amplifier (DCCCTA) and implemented multi-mode biquadratic universal shadow filter. The frequency-hopping filter is implemented using a multi-mode universal shadow filter. The proposed circuit has two modes of operation: current mode (CM) and transadmittance mode (TAM). All-pass (AP), band-pass (BP), band-reject (BR), high-pass (HP), and low-pass (LP) responses are simultaneously accomplished. As intended, low input impedance for CM and high input impedance for TAM are acquired, while high output impedance is attained for both modes of operation. Inter-modulation distortion (IMD), percentage total harmonic distortion (%THD), and Monte Carlo analysis are also obtained. The theoretical results are verified using Cadence Virtuoso in 180 nm TSMC technology.

Dong Hoon Shin, Duk Hyun Lee, Sang‐Jun Choi et al.

Abstract Weak interlayer couplings at 2D van der Waals (vdW) interfaces fundamentally distinguish out‐of‐plane charge flow, the information carrier in vdW‐assembled vertical electronic and optical devices, from the in‐plane band transport processes. Here, the out‐of‐plane charge transport behavior in 2D vdW semiconducting transition metal dichalcogenides (SCTMD) is reported. The measurements demonstrate that, in the high electric field regime, especially at low temperatures, either electron or hole carrier Fowler–Nordheim (FN) tunneling becomes the dominant quantum transport process in ultrathin SCTMDs, down to monolayers. For few‐layer SCTMDs, sequential layer‐by‐layer FN tunneling is observed to dominate the charge flow, thus serving as a material characterization probe for addressing the Fermi level positions and the layer numbers of the SCTMD films. Furthermore, it is shown that the physical confinement of the electron or hole carrier wave packets inside the sub‐nm thick semiconducting layers reduces the vertical quantum tunneling probability, leading to an enhanced effective mass of tunneling carriers.

Daniel J. Schultz, Alexandre Khoury, Félix Desrochers et al.

The triangular lattice Hubbard model at strong coupling, whose effective spin model contains both Heisenberg and ring exchange interactions, exhibits a rich phase diagram as the ratio of the hopping $t$ to onsite Coulomb repulsion $U$ is tuned. This includes a chiral spin liquid (CSL) phase. Nevertheless, this exotic phase remains challenging to realize experimentally because a given material has a fixed value of $t/U$ that can difficultly be tuned with external stimuli. One approach to address this problem is applying a DC electric field, which renormalizes the exchange interactions as electrons undergo virtual hopping processes; in addition to creating virtual doubly occupied sites, electrons must overcome electric potential energy differences. Performing a small $t/U$ expansion to fourth order, we derive the ring exchange model in the presence of an electric field and find that it not only introduces spatial anisotropy but also tends to enhance the ring exchange term compared to the dominant nearest-neighbor Heisenberg interaction. Thus, increasing the electric field serves as a way to increase the importance of the ring exchange at constant $t/U$. Through density matrix renormalization group calculations, we compute the ground state phase diagram of the ring exchange model for two different electric field directions. In both cases, we find that the electric field shifts the phase boundary of the CSL towards a smaller ratio of $t/U$. Therefore, the electric field can drive a magnetically ordered state into the CSL. This explicit demonstration opens the door to tuning other quantum spin systems into spin liquid phases via the application of an electric field.