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

F. Béguin, E. Frąckowiak

Tao Cheng, Sheng Yang, Zi Ye et al.

Abstract Flexible perovskite solar cells hold great potential for lightweight and conformal photovoltaics but their power conversion efficiency (PCE) still lags behind rigid counterparts, particularly in large‐area modules, due to challenges in forming high‐quality films on flexible substrates. To address this challenge, Tan et al. present a scalable gas‐quenching‐assisted in situ additive coating strategy that enables dynamic control of crystallization and synergistic optimization of bulk and interfacial properties (Nat. Photon. 2025, 19, 1255–1263). This approach yields wide‐bandgap perovskite films up to 30 × 40 cm2 on polyethylene terephthalate (PET) under ambient conditions, featuring high crystallinity, low defect density, and pinhole‐free interfaces. Using this method, they achieve a 27.5% PCE in flexible all‐perovskite tandem cells (active area of 0.049 cm2) and a certified 23.0% efficiency in large‐area modules (aperture area of 20.26 cm2). Slot‐die‐coated wide‐bandgap modules (aperture area of 804 cm2) exhibit excellent flexibility, retaining 97.2% efficiency after 10,000 bending cycles and outstanding thermal and operational stability. This work narrows the performance gap between flexible and rigid tandems, advancing scalable, high‐efficiency flexible photovoltaics.

Akimasa Hirata, Ilkka Laakso, Francesca Apollonio et al.

The recent advances in computational dosimetry for electromagnetics and thermodynamics are reviewed to assess human exposure to electromagnetic fields in the MHz-to-terahertz range. This review emphasizes model variability in computational dosimetry. Apart from computational electromagnetic methods and their usage, the developments in anatomical phantoms and tissue dielectric properties characterization are also surveyed. In addition, the rationale for dosimetric quantities prescribed in international exposure guidelines, such as the specific absorption rate (SAR) and absorbed power density, is revisited in relation to their correlation with local and core temperature rises in various tissues and populations. A heating factor, which is defined as a steady-state temperature rise per SAR, for the brain, eye lens, skin, and body core is evaluated to estimate heating resulting from exposure to electromagnetic fields. The transition of a physical quantity in the guidelines at 6 GHz, from SAR to the absorbed power density, is discussed along with the optimal spatial averaging volume and areas. Computational evaluations of product compliance, 5G devices, and wireless power transfer systems are also reviewed. This review aims to synthesize the current knowledge, identify key sources of computational model variability and uncertainty, and outline further research needs for setting exposure guidelines and compliance assessment.

Maryam Saadat Safa, S. Tajik

Stealthy chip-level tamper attacks, such as hardware Trojan insertions or security-critical circuit modifications, can threaten modern microelectronic systems’ security. While traditional inspection and side-channel methods offer potential for tamper detection, they may not reliably detect all forms of attacks and often face practical limitations in terms of scalability, accuracy, or applicability. This work introduces a non-invasive, contactless tamper detection method employing a complementary split-ring resonator (CSRR). CSRRs, which are typically deployed for non-destructive material characterization, can be placed on the surface of the chip’s package to detect subtle variations in the impedance of the chip’s power delivery network (PDN) caused by tampering. The changes in the PDN’s impedance profile perturb the local electric near field and consequently affect the sensor’s impedance. These changes manifest as measurable variations in the sensor’s scattering parameters. By monitoring these variations, our approach enables robust and cost-effective physical integrity verification requiring neither physical contact with the chips or printed circuit board (PCB) nor activation of the underlying malicious circuits. To validate our claims, we demonstrate the detection of various chip-level tamper events on an FPGA manufactured with 28 nm technology.

Ritamay Bhunia, Joo Sung Kim, Hayoung Oh et al.

Abstract The advancements in developing low‐powered artificial tactile cognition devices, inspired by the iontronic‐reliant human haptic sensory system, show great potential in future robotics and prosthetics. However, poor tactile memory and the complexity of integrating diverse modules for tactile sensing and neuromorphic functionalities pose a formidable challenge. Here, a mechanoreceptor‐inspired tactile memory‐in‐sensor (TMIS) device is presented, employing ferroelectric‐assisted ion dynamics (FAID) in FAID‐based synaptic tactile transistor (FAID‐STT). This approach improves the long‐term memory (LTM) of tactile information while minimizing power consumption, all within a unified device architecture of TMIS. The FAID mechanism intricately combines the release of trapped ions solely under mechanical stress with remnant ferroelectric polarization induced by voltage stimulation, ensuring prolonged memory retention. Consequently, the FAID‐STT exhibits a voltage‐dependent memory effect stemming from the augmentation of ferroelectric dipole polarization, offering uninterrupted tactile memory for over 12 min without requiring additional power inputs for memory retention.

Ruoman Yang, Tzu-Chien Hsueh

A low-power time-to-voltage converter (TVC) is composed of a reconfigurable current-mode integrator and a capacitive voltage holder specifically for random sampling-and-averaging (RSA) time-to-digital conversions (TDC) in time-correlated single-photon counting (TCSPC) systems. To accommodate the TVC circuit within each single-photon detection pixel for compact silicon-photonics integration, this paper exploits the Miller-impedance technique to demonstrate the leakage time-constant of the voltage holder being extended up to tens of milliseconds, which represents a more than <inline-formula> <tex-math notation="LaTeX">$100\times $ </tex-math></inline-formula> improvement in high-leakage 22-nm digital CMOS process technology, with only a 9-pF (36-<inline-formula> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>m <inline-formula> <tex-math notation="LaTeX">$\times 36$ </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>m) metal-finger hold capacitor and 120-<inline-formula> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>W power consumption.

Mateusz Mrukiewicz, Martin Cigl, Paweł Perkowski et al.

The oblique helicoidal structure is formed in right-angle cholesterics under the applied electric field. The electric field changes the pitch and cone angle but preserves the single-harmonic modulation of the refractive index. As a result, in such a supramolecular system, we can tune the selective reflection of light in a broad range. Here, we report that structural colors can be tuned by simultaneously illuminating the structure with UV light and the action of an electric field. The cholesterics with the oblique helicoidal structure were doped with newly designed rod-like, chiral, and bent-shaped azo-photosensitive materials characterized by a very low rate of thermal back isomerization. The isomerization of the photo-active compounds under UV light causes the red shift of the selective light reflection in the cholesteric mixtures. We found that the molecular structure of the photosensitive materials used affects the reflection coefficient, bandwidth, response time to UV irradiation, and tuning range. The effect was explained by considering the effect of molecular matching, cis-trans isomerization, and electric field action. We investigated the dynamics of molecular changes in the oblique helicoidal structure under the influence of external factors. The designed supramolecular system has the potential application in soft matter UV detectors.

Chengxiang Zhao, Wenjun Zhang, Haotong Wang et al.

We theoretically investigate the electric field-tuning plasmons and plasmon-phonon couplings of two-dimensional (2D) transition metal dichalcogenides (TMDs), such as monolayer MoS2, under the consideration of spin-orbit coupling. It is revealed that the frequencies of plasmons and coupled plasmon-phonon modes originating from electron-electron and electron-phonon interactions can be effectively changed by using applied driving electric fields. Notably, these frequencies exhibit a decreasing trend with an increasing electric field. Moreover, the weak angular dependence of these modes suggests that the driving electric field does not induce significant anisotropy in the plasmon modes. The outcomes of this work demonstrate that the plasmon and coupled plasmon-phonon modes can be tuned not only by manipulating the electron density via the application of a gate voltage but also by tuning the applied driving electric field. These findings hold relevance for facilitating the application of 2D TMDs in optoelectronic devices.

T. Aditya Sai Srinivas, Ranjeet Yadav, V. Gowri et al.

Physical situations that are duplicated in virtual settings are what the term ''digital twin'' refers to. Utilizing the Internet of Things and sensors to improve microgrid operation, the Microgrid Digital Twin (MGDT) exhibits bidirectional data sharing and sophisticated communication characteristics. Smart grid functionality is enhanced, limits are set in real-time, and data is securely stored by MGDT. It directs the planning and execution phases of microgrid operations. Concurrently, industry and transportation innovation is propelled by the Industrial Revolution. AI-driven ground-dependent controls, communication systems, and sensors are essential for breakthroughs in unmanned vehicle safety. This abstract clarifies how important digital twins more specifically, MGDTs are to system operations optimization. In addition to highlighting technological advancement and the use of AI to ensure the safety of unmanned vehicles, it provides insights into the potentially revolutionary applications of digital twins across a range of industries.

Takumi Kotooka, Sam Lilak, Adam Z. Stieg et al.

Abstract The artificial intelligence (AI) paradigm shifts from software to implementing general‐purpose or application‐specific hardware systems with lower power requirements. This study explored a material physical reservoir consisting of a material random network, called in‐materio physical reservoir computing (RC) to achieve efficient hardware systems. The device, made up of a random, highly interconnected network of nonlinear Ag2Se nanojunctions as reservoir nodes, demonstrated the requisite characteristics of an in‐materio physical reservoir, including but not limited to nonlinear switching, memory, and higher harmonic generation. The power consumption of the in‐materio physical reservoir is 0.07 nW per nanojunctions, confirming its highly efficient information processing system. As a hardware reservoir, the devices successfully performed waveform generation tasks. Finally, a voice classification by an in‐materio physical reservoir is achieved over 80%, comparable to an RC software simulation. In‐materio physical RC with rich nonlinear dynamics has huge potential for next‐generation hardware‐based AI.

Xiao Ye, Xin lv

The Android system has good compatibility, freedom, rich hardware resources and a good development environment. At the same time, it can also work with Google services to obtain external support. Android is an open source operating system platform, which is similar to the iOS platform. In contrast, developers have more room for development, making the Android platform more people use. This article aims to develop a mobile medical system based on the Android operating system that integrates search engines, maps, and hospital HIS systems. The users are mainly patients, doctors and system administrators. Patients can register online and use mobile healthcare to pay online. They can also upload various physical indicators to record their daily health status. The establishment of health files is convenient for doctors to make health assessments and provide patients with medical consultation and medical health protection. Patients can also realize hospital navigation, intra-hospital navigation, and view various hospital inspection reports through the APP. The design of mobile medical service system is to design user behavior in the system based on the concept of service design. Therefore, in the process of system design, it is necessary to comprehensively consider service design principles and related factors, and propose behavior design principles that conform to service design theory. This study uses a mutual continuation care platform to implement seamless care for patients. Patients and medical staff can realize the continuation of the relationship and the continuity of information, and the patients can receive comprehensive guidance in a timely and effective manner. It can provide a reference basis for improving the continuity management and information management of patients in China, and provide reference value for the standardization and standardization of patients' continuation of nursing care standards and procedures.

Hairu Wang, Oskar Zetterstrom, Pilar Castillo-Tapia et al.

In this work, we examine the methodology for numerically computing the dispersion diagram of three-dimensional periodic structures using commercial electromagnetic simulators. Examples of periodic structures based on body-centered cubic, face-centered cubic, and monoclinic lattices are used to illustrate this methodology. We first outline the characteristics of these structures in both physical and reciprocal spaces from a theoretical point of view. On this basis, we provide a comprehensive explanation of how to adjust the setting in simulation software commonly used in microwave engineering to generate the dispersion diagrams of these structures. The appropriate simulation conditions are tabulated to serve as a further guide for other researchers. This study also explores the influence of the elements of the unit cell on the dispersion characteristics. Additionally, we evaluate and contrast the dispersion properties of identical periodic elements when having simple cubic, body-centered cubic, and face-centered cubic arrangements. We found that symmetries, such as those seen in body-centered cubic and face-centered cubic arrangements, can improve the isotropy and maintain low-dispersion characteristics over a wider frequency range. The monoclinic structure is also taken as an example to demonstrate that the reported analysis method can be applied to the dispersion analysis of other more complex noncubic lattices. Our findings offer useful information for the examination and engineering of three-dimensional periodic structures, which can be used to design microwave and antenna devices.

Zeyu Chen, Fan Wu, Rajesh Pathak et al.

Abstract This research delves into the effects of 2D layers on the functionality of 3D perovskite using lock‐in amplifier‐based in situ surface photovoltage (SPV) and its phase spectroscopy, with an emphasis on elucidating the connection between the tuning of dipole moments and the photocurrent hysteresis. Conventionally, the SPV of a perovskite/hole transport layer is observed to diminish as positive bias escalates. However, this trend is reversed in the case of 3D perovskite samples, where an augmentation in SPV is noted under positive bias. Notably, 3D/2D perovskite structures initially show a decrease, then an increase in SPV as bias intensifies, a phenomenon more pronounced with larger dipole moments in 2D. However, there is no linear relationship between the dipole moment and the hysteresis factor. Furthermore, using in situ light‐chopping‐frequency‐modulated SPV and Kelvin Probe Force Microscopy, it is revealed that the dipole fields of 2D layers can hinder ion migration. This leads to efficient hole transfer and minimal photocurrent hysteresis in 3D/2D perovskites, providing strong evidence for the underlying cause of hysteresis. Additionally, these findings suggest intricate interplays among the external electric field, interface dipole moments, and surface photovoltaics, offering significant insights into perovskite optoelectronics.

Priyanka Agrwal, Ajay Kumar

In this work, a high-k In0.53Ga0.47As silicon-on-insulator FinFET (InGaAs–SOI–FinFET) is presented for high-switching and ultra-low power applications at 7 nm gate length. Indium Gallium Arsenide (InGaAs) is a compound semiconductor that has gained attention in the field of semiconductor devices, including FinFETs. The incorporation of InGaAs in proposed FinFETs introduces several advantages, making it an attractive material for certain applications. InGaAs–SOI–FinFET performance has been observed and found high electron mobility, improved On-Current performance (ION), drain current (IDS), transconductance (gm), energy bands, lower subthreshold swing (SS), electric field, surface potential, and better short-channel behaviour. All the results of InGaAs–SOI–FinFET have been simultaneously compared with SOI-FinFET and conventional FinFET (C-FinFET). Incorporating InGaAs in the channel with high-k gate material enhances the drain current by ⁓75% and ⁓77% in the proposed device compared to the other two counterparts. Owing to the higher drain current in the InGaAs–SOI–FinFET, other parameters have also been improved, which leads to higher performance applications.

Teruo Matsushita

A. Vinogradov, A. Vinogradova, A. Bukreev et al.

A literature review was carried out, which showed a shift in the emphasis of digital transformation of the electric power industry on the development of methods and means of automation of rural electric networks of 0.4-10 kilovolts. It is shown that the actual direction of automation of rural electric networks is the development of means of their partitioning and redundancy, including the creation of relatively inexpensive devices for partitioning – dividing power lines into sections. The use of these devices requires the creation of methods for selecting their installation locations in electrical networks. (Research purpose) The research purpose is developing a methodology for locating the installations for sectioning the electrical grid. (Materials and methods) Analyzed literature sources, existing methods for selecting installation sites for partitioning tools. We used general scientific methods, methods of reliability theory, electrical engineering. (Results and discussion) Suggested options for the placement of devices for dividing the electrical network, depending on the purpose of their use. The criteria for choosing the installation locations of the electrical network division devices were given, which included ensuring the protection of the power transmission line from remote short circuits, primarily single-phase, increasing the reliability of power supply to consumers, preventing voltage deviation from exceeding permissible limits. Presented a methodology for selecting the installation locations of electrical network division devices according to the proposed criteria. (Conclusions) It was revealed that for radial and radial with soldering of electrical networks, the main criterion is to ensure the protection of remote short circuits, and an additional one is to increase the reliability of power supply. It has been shown that for ring networks, the main criterion is to prevent voltage deviation from exceeding permissible limits along with the criterion of ensuring protection from remote short circuits, and the criterion for increasing reliability is an additional one. It was established that the final place of installation of devices for dividing the electrical network into sections in each case is determined taking into account the specified criteria so that the main ones are not violated.

A. I. Orlov, Sergei V. Volkov, I. Garipov

Practical calculations of electric equipment and electric networks are performed using equivalent circuits. Without taking into account saturation phenomena, electromagnetic processes in a power transformer are described by a system of linear equations, which can be represented in matrix form. The transformer inductance matrix contains self and mutual winding inductances, whose values for one phase are determined directly from the passport data containing the results of no-load and short circuit experiments. Mutual inductances between phases depending on the type and size of the magnetic core are not usually given in the transformer documentation. It does not allow to simulate the operating modes that differ from the steady state with uniform phase load. The purpose of the work is to develop an algorithm for calculating elements of the power transformer inductance matrix according to its passport data and magnetic circuit parameters. The scientific novelty lies in use of information about magnetic circuit type and size to determine elements of the inductance matrix. Materials and methods. Methods of linear electric and magnetic circuit theory are used in the work. Results. The proposed algorithm for calculation of power transformer inductance matrix includes three stages: calculation of self and mutual inductances for one phase; construction of an equivalent circuit for a magnetic circuit and calculation of magnetic fluxes in order to take into account the mutual influence of windings on various phases; assembly of the inductance matrix of three-phase transformer. A method is proposed for constructing the transformer inductance matrix with an arbitrary type of magnetic circuit, phases and windings quantity. The method involves preliminary calculation of the coefficient matrix that characterizes the magnetic circuit and depends mainly on its type and, to a less, on the ratio of geometric dimensions in rods and yokes. The coefficient matrix can be calculated in advance and used to determine the inductance matrix of a wide range of transformers. Conclusions. 1. The passport data of the transformer do not allow to model transformer operation at unbalanced load validly. 2. An algorithm for determining the inductance matrix of transformers has been developed. 3. A method for compilation of a transformer inductance matrix with an arbitrary type of magnetic circuit, the number of phases and windings is introduced. The practical significance of the algorithm is determined by the simplicity of algorithmizing, as well as by the possibility of using it in computer simulation of electrical circuits with transformers, for example, using the modified nodal analysis method.

D. R. Jones, P. Brown, G. McFarland et al.

Using near-field scanning microwave microscopy as a contact and non-contacting investigative tool for 3D surface metrology with three differing measurement modes, it has been possible to analyse structures that may be difficult for existing metrology systems. The system utilizes the small change in capacitance between a coaxial resonant probe (at around 2 GHz) ending in an open circuit tip, and the sample surface. This is measured in the frequency domain by the shift in the resonance frequency of the voltage transmission coefficient &#x007C;S₂₁&#x007C;. It is also possible to investigate various materials (metallics, plastics etc.) owing to their differing dielectric properties. The probe has been tested on a computer-controlled 3D stage but is suitable for incorporation into a commercial co-ordinate measurement machine (CMM) to enhance its capability to inspect the inside surfaces of structures, e.g., threads in small bores.

Alessandro Ciani, David P. DiVincenzo, Barbara M. Terhal

During the last 30 years, stimulated by the quest to build superconducting quantum processors, a theory of quantum electrical circuits has emerged and this theory goes under the name of circuit quantum electrodynamics or circuit-QED. The goal of the theory is to provide a quantum description of the most relevant degrees of freedom. The central objects to be derived and studied are the Lagrangian and the Hamiltonian governing these degrees of freedom. Central concepts in classical network theory such as impedance and scattering matrices can be used to obtain the Hamiltonian and Lagrangian description for the lossless (linear) part of the circuits. Methods of analysis, both classical and quantum, can also be developed for nonreciprocal circuits. These lecture notes aim at giving a pedagogical overview of this subject for theoretically-oriented Master or PhD students in physics and electrical engineering, as well as Master and PhD students who work on experimental superconducting quantum devices and wish to learn more theory.

Ping Tang, Gerrit E. W. Bauer

We analyze the ``ferron" excitations in order-disorder ferroelectrics by a microscopic pseudo-spin model. We demonstrate that analogous to magnons, the quanta of spin waves in magnetic materials, ferrons carry both static and oscillating electric dipole moments, exhibit a Stark effect, and may be parametrically excited by THz radiation. The anti-crossing gap of the ferron-photon hybrid depends strongly on propagation direction and an applied static electric field. We predict ferron diffusion lengths that can reach centimeters, which implies efficient transport of electric polarization by temperature gradients. These properties suggest that ferroelectric materials may be useful for information technology beyond data storage applications.