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

Ruimin Cai, Cunman Liang, Yongqing Duan et al.

Abstract Flexible printed electronics represent a cutting‐edge technology leveraging functional inks to fabricate electronic circuits and components on diverse flexible substrates. Various advanced printing processes enable the production of computer‐controlled patterns with superior resolution and flexibility. Advances in low‐temperature sintering techniques have significantly propelled the evolution of flexible printed electronics by reducing thermal impact on substrates, ensuring high‐quality device fabrication. Functional nanomaterial inks serve as the cornerstone of this technology, with metallic nanoparticle inks being widely utilized for their superior electrical conductivity, facile synthesis, and commendable biocompatibility. Here, we comprehensively review the synthesis and processing of metallic nanoparticle inks and critically comment on different types of metallic nanoparticle inks, and believe that composite metallic nanoparticle inks have more advantages in reducing cost and improving comprehensive performance. In addition, this paper summarizes the various printing processes and sintering techniques, emphasizing the printing mechanisms and the recent advances in low‐temperature sintering technology. The applications of metallic nanoparticle inks in various scenarios, such as sensors, wireless technologies, energy storage and electroluminescent devices, are summarized. Lastly, the current challenges facing metallic nanoparticle inks are critically analyzed, and forward‐looking strategies and advances aimed at addressing these obstacles are proposed.

Rabah Benabid

This paper deals with energy system optimization and planning using message code. The problem is formulated as a mixed integer programming problem with constraints on activities and installed capacities. The objective function is the minimization of the total installation cost including the investment cost, the variable and fixed operation and maintenance costs, and the constraints violation cost. Various operation and environmental constraints are considered.  The obtained results show the capability of message code to model and solve the complex energy planning problem considering different types of constraints.

Ken B. Cooper, Jose V. Siles, Juan M. Socuellamos et al.

We present the design and testing of a >400 mW solid-state G-band transmitter developed for cloud radar applications. The source relies on GaAs on-chip power-combined Schottky diode frequency-triplers operating over a bandwidth that includes the 238–240 GHz span allocated for radar. High continuous-wave output power is achieved with additional four-way waveguide power combining, for a total of eight Schottky diode frequency-tripler circuits. This device achieves a conversion efficiency of ∼15% near 240 GHz, and was measured to have an 8% fractional bandwidth spanning 235–255 GHz. The source has been integrated into the Jet Propulsion Laboratory’s CloudCube radar instrument for profiling clouds and drizzle to reveal aspects of their microphysics and dynamics.

Yujue Yang, Mengjia Xia, Qixiao Zhao et al.

Abstract 2D 1T‐VSe2 is a charge‐density wave (CDW) system that also exhibits room‐temperature ferromagnetism, making it promising for photodetecting devices. However, the sensitivity of 1T‐VSe2 photodetectors is limited by the high dark current due to its metallic feature of T‐phase VSe2. So far, photodetectors based on semiconducting 2H‐phase VSe2 have ever been reported. In this work, the metal‐semiconductor phase transition (1T to 2H) in multilayer VSe2 by thermal annealing process, and the fabrication of 2H‐VSe2 broadband photodetectors with high sensitivity is reported. The 2H‐VSe2 photodetectors exhibit low dark current and a broad spectral range of 405–1550 nm. The responsivity (R) and detectivity (D*) can reach up to 75.26 A W−1 and 1.45 × 1010 Jones at Vsd of 1 V, outperforming photodetectors based on 1T‐VSe2 and other 2D materials for the 1550 nm optical communication band. This work showcases a facile method for obtaining the metal‐semiconductor phase transition of VSe2 and demonstrates the potential of 2H‐VSe2 for high‐performance near‐infrared photodetectors.

Amirhossein Rostami, Seyed Mohammad Ali Zeinolabedin, Liyuan Guo et al.

Over the last few years, online training of deep neural networks (DNNs) on edge and mobile devices has attracted increasing interest in practical use cases due to their adaptability to new environments, personalization, and privacy preservation. Despite these advantages, online learning on resource-restricted devices is challenging. This work demonstrates a 16-bit floating-point, flexible, power- and memory-efficient neural learning unit (NLU) that can be integrated into processors to accelerate the learning process. To achieve this, we implemented three key strategies: a dynamic control unit, a tile allocation engine, and a neural compute pipeline, which together enhance data reuse and improve the flexibility of the NLU. The NLU was integrated into a system-on-chip (SoC) featuring a 32-bit RISC-V core and memory subsystems, fabricated using GlobalFoundries 22nm FDSOI technology. The design occupies just <inline-formula> <tex-math notation="LaTeX">$0.015mm^{2}$ </tex-math></inline-formula> of silicon area and consumes only 0.379 mW of power. The results show that the NLU can accelerate the training process by up to <inline-formula> <tex-math notation="LaTeX">$24.38\times $ </tex-math></inline-formula> and reduce energy consumption by up to <inline-formula> <tex-math notation="LaTeX">$37.37\times $ </tex-math></inline-formula> compared to a RISC-V implementation with a floating-point unit (FPU). Additionally, compared to the state-of-the-art RISC-V with vector coprocessor, the NLU achieves <inline-formula> <tex-math notation="LaTeX">$4.2\times $ </tex-math></inline-formula> higher energy efficiency (measured in GFLOPS/W). These results demonstrate the feasibility of our design for edge and IoT devices, positioning it favorably among state-of-the-art on-chip learning solutions. Furthermore, we performed mixed-precision on-chip training from scratch for keyword spotting tasks using the Google Speech Commands (GSC) dataset. Training on just 40% of the dataset, the NLU achieved a training accuracy of 89.34% with stochastic rounding.

Chad Bartlett, Michael Hoft, Uwe Rosenberg

A novel wideband multiplexer is introduced as a communications equipment solution in order to provide simultaneous operation of satellite and terrestrial services in the dedicated <inline-formula><tex-math notation="LaTeX">$K$</tex-math></inline-formula>/<inline-formula><tex-math notation="LaTeX">$Ka$</tex-math></inline-formula> frequency bands (passbands ranging from 19.5 GHz to 30.5 GHz). Advanced RF filtering techniques are applied in order to accommodate a compact multiplexer design while maintaining low insertion loss and high rejection demands up to 33 GHz. Due to the overall wide bandwidth and the demanding requirements for the assigned three operational bands, different filter types have been employed. Thus, the multiplexer considers the combination of filters with rectangular, evanescent combline, and conductor-loaded resonator types. The multiplexer relies on the direct branching approach, i.e., all filters are connected to a central (star-junction) waveguide branching region. This region exhibits a reduced waveguide size to suppress interference by higher order modes. For a verification of the approach, WR34 waveguide interfaces have been considered at all ports for prototype design, however, the design can be well adapted for integrated equipment solutions with associated direct interfaces. Accurate coincidence of analyzed and measured performance of the prototype demonstrates the validity of the special approach. Moreover, additional simulations are provided as an outline for terminals with specific industry demands.

FADILA TAHIRI, Abdelkader HARROUZ, Gazi Erkan BOSTANCI

This paper aims to study the behavior of different maximum power point tracking (MPPT) techniques applied to PV systems. In this work, we evaluate and compare perturbation and observation (P&O) and sliding mode control (SMC) techniques. a DC/DC boost converter is used between the PV system and load to transfer the maximum possible power. the conventional MPPT methods Perturb and Observe (P&O) cannot detect and track the highest peak. Thus, this causes an important loss of power, so a technique is suggested sliding mode control, which offers many benefits such as durability against parameter changes, minimal current output distortion, and excellent reference tracking. The simulation results shown in MATLAB confirm that the sliding mode control method allows to have a faster response compared to P&O, to reduce the steady-state fluctuations and better track the maximum power point with fewer power losses.

Asma LARIBI, Aissa BOUTTE , El Yazid BELAIDI et al.

By the PEDAGOSAT project we aim to democratize all educational activities related to CubeSat-class: nanosatellite, from physics through engineering, technical achievements, integration, to testing and operations to the greatest number of students. The key idea is to eventually have our academic nanosatellite training platform offering an open source opportunity to Algerians universities, and having the capacity to cover all engineer training areas relating to "small satellites". As part of this project, some satellite subsystems, test and emulation facilities will be realized, processes and procedures for testing and integration related to space technology will be addressed, implemented and even mastered. The presented work is part of the development of the on-board power system, and covers the selection of solar cells for the manufacture of solar panels of this satellite. The main source of energy present in space is solar energy, it a continuous and inexhaustible source that a satellite can. In satellite we use a solar panel to ensure its operation. In the dimensioning of a satellite, it is essential to identify these electrical power requirements named “power budget analysis”. Indeed, this makes it possible to determine the number of cells and/solar panels to be installed to guarantee the power continuity of the satellite in sunlight phase of its orbit by recharging its batteries and feeding equipment’s. During all the mission duration; from the beginning of life (BOL) after the launch to it deorbits (EOL) to disintegrate in the atmosphere. For the PEDAGO-SAT as for other satellites, it will be necessary to verify the parameters and physical characteristics of the solar cells/panels according to certified procedures and methodologies in order to be able to pronounce on their qualification for aerospace use. In this context, we propose a low-cost process revision to be able to carry out qualification tests with an accessible facility in the university labs. This revision will also concern the development of homemade means and software that fit the investments that may be made by the Algerian research and academic facilities. As illustrated in this paper a performance evaluation of low-cost solar cells was done using the developed solution and the selected cells will be integrated in the solar panels of PEDAGOSAT.

Zhe (A.) Jian, Kai Sun, Stefan Kosanovic et al.

Abstract Wafer bonding of β‐Ga2O3 and N‐polar GaN single crystal substrates is demonstrated by adding ZnO as a “glue” interlayer. The wafers are fully bonded such that Newton rings are not observed. Temperature‐dependent current‐voltage (I–V) measurements are conducted on the as‐bonded Ga2O3/ZnO/N‐polar GaN test structure and after annealing at 600 °C and 1100 °C. The impact of post‐annealing temperature on the electrical and structural characteristics of the bonded samples is investigated. A consistently ohmic‐like characteristic is obtained by annealing the bonded wafers at 1100 °C in N2, which is in part due to crystallization of ZnO and diffusion of Ga into ZnO which makes it n‐type doped. The wafer bonding of β‐Ga2O3 and GaN achieved in this work is promising to combine the material merits of both GaN and Ga2O3 targeting breakthrough high‐frequency and high‐power device performances.

Mare Srbinovska, Vesna Andova, Aleksandra Krkoleva Mateska et al.

Low quality of the air is becoming a major concern in urban areas. High values of particulate matter (PM) concentrations and various pollutants may be very dangerous for human health and the global environment. The challenge to overcome the problem with the air quality includes efforts to improve healthy air not only by reducing emissions, but also by modifying the urban morphology to reduce the exposure of the population to air pollution.The aim of this contribution is to analyse the influence of the green zones on air quality mitigation through sensor measurements, and to identify the correlation with the meteorological factors. Actually, the objective focuses on identifying the most significant correlation between PM2.5 and PM10 concentrations and the wind speed, as well as a negative correlation between the PM concentrations and wind speed across different measurement locations. Additionally, the estimation of slight correlation between the PM concentrations and the real feel temperature is detected, while insignificant correlations are found between the PM concentrations and the actual temperature, pressure, and humidity.In this paper the effect of the pandemic restriction rules COVID-19 lockdowns and the period without restriction are investigated. The sensor data collected before the pandemic (summer months in 2018), during the global pandemic (summer months 2020), and after the period with restriction measures (2022) are analysed.

Yuhang Song, Zhiming Dai, Long Liu et al.

Abstract Field‐free switching is a critical issue for spin‐orbit torque‐induced magnetic random‐access memory (SOT‐MRAM) with perpendicular magnetic anisotropic (PMA) towards application. If only the spin‐polarized electrons along the y‐direction (σy) are used, deterministic switching cannot be achieved, as the electron polarization direction and easy magnetization direction are orthogonal. In this work, z‐direction polarized electrons (σz) produced by the spin Hall effect are utilized to provide the switching direction and σy provides the propulsion of magnetic reorientation. With the cooperation of σy and σz by the spin Hall effect, field‐free switching is achieved. To combine with magnetic tunnel junction (MTJ), a model is proposed, in which heavy metals providing σz are deposited on MTJ with asymmetric writing line widths. This model retains the characteristics of read‐write separation and realizes deterministic switching based on SOT.

Giulio Fatti, Alessandra Ciniero, Hyunseok Ko et al.

Abstract The lack of theoretical understanding of triboelectrification has hindered the development of energy harvesting technologies like triboelectric nanogenerators. Focusing on polytetrafluoroethylene, a material with a strong triboelectric output, a model predictive of its triboelectric behavior, driving the development of improved nanogenerators are formulated. With a combined computational‐experimental approach it is shown that defluorination enhances polytetrafluoroethylene nanoscale triboelectric charging. Then a model, explaining the macroscale triboelectric output as determined by the competition of two mechanisms is developed. Defluorination enhances charging while also reducing the interface gap, favoring the backflow of electrons, and possibly reducing charging. However, numerical analysis shows that backflow is negligible, aligning with the prediction of increased triboelectric output. By building triboelectric nanogenerators with defluorinated polytetrafluoroethylene samples, achieved by X‐ray irradiation, a one‐order‐of‐magnitude output increase is demonstrated. The predictive models, supported by experiments, lead to an improved strategy for designing effective energy harvesting devices and new applicative breakthroughs.

Alejandro Talaminos-Barroso, Javier Reina-Tosina, Laura M. Roa

Healthcare information systems are evolving from traditional centralised architectures towards highly-mobile distributed environments within the connected health context. The IoMT paradigm is at the forefront of this technological revolution underlying the development of communication infrastructures connecting smart medical devices, healthcare information systems and services. The IEEE 2413 standard, a promising general architectural framework for the design and implementation of IoT systems, has recently been announced. This standard proposes a general description for different types of domains, including healthcare, but it does not contain an extension developed for the IoMT systems domain. This paper presents a first approach to adapt the IEEE 2413 standard to the design of IoMT systems from a security perspective, considering the most relevant aspects of the standard for the construction of this type of systems. The application to an IoMT system for monitoring patients with chronic obstructive pulmonary disease is presented as a use case.

Yong Sun, Wansheng Li, Yucheng Zhao et al.

Image recognition of pointer instrument based on machine vision has been widely used. However, traditional algorithms are inadequate in the case of intersectant dual-pointer instrument. This paper provides a complete solution, including image pretreatment, extraction of the position of pointer and reading identification. In particular, the target line segment filter method is invented.

Aman Batra, Jan Barowski, Dilyan Damyanov et al.

Synthetic aperture radar (SAR) is a well-known imaging technique and most commonly used up to the microwave frequency spectrum (below 30 GHz) which provides spatial resolution in the sub-m range. To enhance the resolution, higher frequency spectra such as millimeter-wave (mmWave) and terahertz (THz) regions are being investigated. The mmWave and THz spectral ranges extend the SAR applications to non-destructive testing (NDT), material characterization, and sub-mm resolution imaging. However, the higher frequency spectrum suffers from higher path loss and potentially higher atmospheric absorption that limits the propagation distance. Nevertheless, the mmWave/THz spectrum is suitable for short-range applications such as indoor room profiling. From theoretical analysis, it can be summarized that the higher frequency spectrum provides better resolution but a comparative study on the impact on the image quality of the frequency spectrum ranging from GHz to THz has not been presented. Besides, as of the hardware complexity of the THz devices, the optimum range of the spectrum is always under investigation. The optimum range is defined where no strong improvements in the image quality are achievable with further increases in the frequency spectrum. Therefore, this paper presents an overview of electronics-based imaging using the SAR technique for the frequency spectrum ranging from GHz to THz with the focus on NDT and high-resolution imaging. Seven frequency bands: 5-10 GHz, 68-92 GHz, 75-110 GHz, 0.122-0.168 THz, 0.22-0.33 THz, 0.325-0.5 THz, and 0.85-1.1 THz are selected for a comparative analysis. The results are presented for 2D and 3D imaging using the backprojection algorithm. Additionally, state-of-the-art imaging based on SAR technique with electronics transceiver modules has only been demonstrated up to the sub-0.75 THz, whereas in this paper the spectrum up to 1.1 THz has been addressed.

DhiaElhak MESSAOUD, Boualem Djezzar, Abdelmadjid Benabdelmoumene et al.

To measure the entire characteristic of p-MOSFET, we have implemented the fast Ids-Vgs technique. The latter is used to study NBTI phenomenon with measure-stress-measure method, for electric field 5MV/cm < Eox < 7.5MV/cm, and temperatures 27°C < Ts < 120°C. Measurement time has reached 10 us, and a stress-measure delay (switching time) of about a hundred of milliseconds was obtained. However, strengths and weaknesses of the implemented technique have been discussed. Furthermore, the extraction methods: transconductance (Gm), subthreshold slope (SS), and mid-gap (MG), have been implemented and discussed as well. NBTI parameter i.e. Delta Vth, n, gamma and Ea were extracted and compared to other results. A time exponent n of 0.149 has been touched. Activation energy Ea = 0.039 eV and a field factor gamma = 0.41 MV/cm for a stress time ts < 10 s have been obtained.

Mirosław Wojtyła, Paweł Rosner, Alistair B. Forbes et al.

A research work is presented, carried out to validate a method based on sensitivity analysis for evaluating the uncertainty of CMM measurements. The fitness for purpose of cylinder squares for verifying the uncertainty evaluation of coaxiality measurements has been confirmed. Ring gauges too were used and found useful, but only as to its diameter. A type B method for predicting the uncertainty considering the actual technical condition of the CMM is proposed.

Hoang-Uyen-Dung Nguyen, Dang-Trang Nguyen, Kozo Taguchi

Soil moisture and irrigation schedules generate impressionable agricultural productivity. In recent years, Soil Microbial Fuel Cell (SMFC) has been recently used as a sustainable technology because of its highly effective applications in power generation, environment pollution treatments, and sensing. Controlling the moisture of soil has a heavy impact on agricultural management. In this study, we set up a new design of SMFC for sensing soil water content. The SMFC is portable, compact, and easily installed. The SMFC operated at four states of soil moisture of 40%, 60%, 80%, and 100% soil water holding capacity (SWHC) was investigated in 25 days. The SMFC showed the highest humid sensitivity in the range from 60% to 80% SWHC. In the range of less than 60% SWHC, the soil moisture was not enough to activate and maintain the SMFC operation.

Yasuki Kawamura, Tohru Nakano

We evaluated the non-uniqueness of the temperature scale of the standard platinum resistance thermometer (SPRT) calibrated at the tripe point of sulfur hexafluoride (TPSF6), which is one of the candidates for the substitute of the triple point of mercury (TPHg). Three SPRTs calibrated at the TPSF6 were compared with a reference thermometer from 14 K to 250 K by using a precise comparison system for capsule type of thermometers. The uncertainty of the temperature scales from propagation of the uncertainties for calibrating SPRT was also evaluated. The result shows that the non-uniqueness of the temperature scale of the SPRT calibrated at the TPSF6 was almost equivalent to that of the ITS-90. This means that the triple point of TPSF6 possessed a capability for realization of the temperature scale which was equivalent to the ITS-90.

Koichi Kurita

In this study, the ultra-sensitive electrostatic induction current detection technology is used to detect the motion of getting on and off the motorcycle under non-contact conditions as an example of daily activities. The detected waveforms are wavelet-transformed to obtain scalograms. Comparing these obtained scalograms, it is shown that the scalogram patterns of the same subjects are almost reproducible and that the scalogram patterns are different among the subjects. Therefore, individual identification by deep learning is carried out using these scalograms. Consequently, it is shown that personal identification is possible with an accuracy of 92.7% using the movement of riding a motorcycle.