In this work, flexible solar blind Ga 2 O 3 ultraviolet photodetectors with high responsivity and photo-to-dark current ratio are demonstrated. The Ga 2 O 3 films are obtained by the RF magnetron ...sputtering method on flexible polyimide (PI) substrates and the results demonstrate that all the films grown under various temperatures are amorphous. When the incident light wavelength is less than 254 nm, the incident light is effectively absorbed by the Ga 2 O 3 film. By controlling the growth temperature of the material, the responsivity and photo-to-dark current ratio of the corresponding metal-semiconductor-metal photodetectors are significantly improved. At growth temperature of 200 °C, the current under 254 nm illumination obtains 396 nA at voltage of 20 V (corresponding responsivity is 52.6 A/W), the photo-to-dark current ratio is more than 10 5 , and the external quantum efficiency reaches 2.6 × 10 4 %, which is among the best reported Ga2O3 ultraviolet photodetectors including the devices on the rigid substrates. After the bending and fatigue tests, the flexible detectors have negligible performance degradation, showing excellent mechanical and electrical stability.
As a promising ultra-wide bandgap semiconductor, the β -phase of Ga 2 O 3 has attracted more and more interest in the field of power electronics due to its ultra-wide bandgap (4.8 eV), high ...theoretical breakdown electric field (8 MV/cm), and large Baliga's figure of merit, which is deemed as a potential candidate for next generation high-power electronics, including diodes, field effect transistors (FETs), etc. In this article, we introduce the basic material properties of Ga 2 O 3 , and review the recent progress and advances of β -Ga 2 O 3 based metal-oxide-semiconductor field-effect transistors ( mosfet s). Due to the problematic p-type doping technology up to now, the enhancement-mode (E-mode) β -Ga 2 O 3 FETs face more difficulties, compared with depletion mode (D-mode). This article focuses on reviewing the recent progress of E-mode Ga 2 O 3 mosfet s, summarizing and comparing various feasible solutions when p-type doping is absent. Furthermore, the device fabrication and performances of state-of-art β -Ga 2 O 3 mosfet s, including D-mode, E-mode, and planar/vertical structure are fully discussed and compared, as well as potential solutions to the challenges of Ga 2 O 3 FETs.
Industry 4.0 is accelerating, with manufacturing enterprises embracing digital transformation and intelligent manufacturing (iM) to enhance competitiveness. Manufacturing enterprises must also ...improve their environmental performance to meet the goal of net zero by 2050 and to avoid border carbon tax imposed by large economies. Thus, green intelligent manufacturing (GiM), i.e., conducting iM while pursuing to maximize energy conservation and carbon reduction, has become the key development trend and a fundamental challenge for the modern manufacturing industry. To address the challenges of green intelligent manufacturing (GiM), this paper proposes a novel framework called Industry 4.2 for GiM (I4.2-GiM). This framework builds on the Intelligent Factory Automation (<inline-formula> <tex-math notation="LaTeX">i</tex-math> </inline-formula>FA) platform, which the authors developed to achieve zero-defect manufacturing (i.e., Industry 4.1). I4.2-GiM uses various IoT devices, called Cyber-Physical Agents (CPAs), to collect and integrate large amounts of data. It also includes two interrelated systems, an intelligent carbon emission management system (<inline-formula> <tex-math notation="LaTeX">i</tex-math> </inline-formula>CMS) and an intelligent energy management system (<inline-formula> <tex-math notation="LaTeX">i</tex-math> </inline-formula>EMS), simultaneously tackling carbon reduction and energy saving. Existing factory EMSs typically save less than 10% of energy, but I4.2-GiM has been shown to conserve 10.9% of energy and reduce carbon emissions by 12.55% while conducting iM in daily production. I4.2-GiM is a promising new framework that can help manufacturing enterprises approach net zero intelligently. Note to Practitioners -This paper proposes a new green intelligent manufacturing (GiM) framework called I4.2-GiM (Industry 4.2 for GiM). I4.2-GiM builds on the Intelligent Factory Automation (<inline-formula> <tex-math notation="LaTeX">i</tex-math> </inline-formula>FA) platform, which the authors developed to achieve zero-defect manufacturing (i.e., Industry 4.1). I4.2-GiM also uses various IoT devices called Cyber-Physical Agents (CPAs) to collect data from multiple sources. It also includes two interrelated systems, an intelligent carbon emission management system (iCMS) and an intelligent energy management system (iEMS), to address carbon reduction and energy saving simultaneously. Moreover, this paper provides a systematic implementation procedure and several practical examples to help practitioners adopt the designs and niches of I4.2-GiM and build their desired GiM systems for reaching the goal of net zero.
A new class of twin Sudoku tables (TSTs) is presented. These tables can be divided into both <inline-formula><tex-math notation="LaTeX">s \times d</tex-math></inline-formula> and ...<inline-formula><tex-math notation="LaTeX">d \times s</tex-math></inline-formula> subtables. They are constructed using the cyclotomic cosets of <inline-formula><tex-math notation="LaTeX">Z_n</tex-math></inline-formula> via two distinct vectors of cyclotomic coset elements and their Kronecker product. We prove that it is possible to generate <inline-formula><tex-math notation="LaTeX">m</tex-math></inline-formula> TSTs that are strongly mutually distinct (SMD), i.e., for every <inline-formula><tex-math notation="LaTeX">0\leq i, j \leq m-1</tex-math></inline-formula>, the <inline-formula><tex-math notation="LaTeX">(i,j)</tex-math></inline-formula>th entry of the tables contains different symbols. We also provide a method to construct <inline-formula><tex-math notation="LaTeX">m</tex-math></inline-formula> different TSTs that can be converted into twin solid Sudoku tables (TSSTs) as a perfect set of SMD TSSTs in order to make triplet solid Sudoku cubes (TSSCs). These TSSCs are symmetric cubes so that a cut from any of the six faces is a TSST. As a result, new twin Sudoku puzzles (TSPs) and SMDTSPs are obtained that can be used to design new types of Sudoku games.
We demonstrate the factors that determine the tunneling electroresistance (TER) of the ferroelectric tunnel junction (FTJ) by investigating the effects of temperature ( T ) and the number of cycles ( ...N ) on remnant polarization ( P r ) and carrier transport process. The fabricated FTJs have a metal/ ferroelectric/ insulator/semiconductor structure. The P r is increased with increasing T and N due to oxygen vacancy redistribution. However, the increased P r in a higher T and N does not improve the TER ratio. Using current-voltage characterization and low-frequency noise spectroscopy, we reveal that the carrier transport process at the interface between the ferroelectric and dielectric layers becomes more important than P r in determining the TER ratio.
In recent days, the usage of data transmission has increased in Wireless Sensor Network (WSN) environments due to its dynamic nature. However, WSNs face many issues during data transmission, such as ...less energy efficiency, less security, and less network lifetime. Here, in this research it presents secure and energy-efficient clustering and routing techniques for an edge-assisted WSN environment to address these problems. The proposed work includes four major processes: Quad tree-based network construction, energy-efficient clustering, RL-based duty cycling, and secure multipath routing. This work constructs the network based on a quad-tree structure to increase network management performance and reduce complexity. After network construction, authentication of sensors is performed by considering ID and location using the Lightweight Encryption Algorithm (LEA), which provides high security by eliminating illegitimate sensor nodes. Then, this research model performs clustering using Tasmanian Devil Optimization (TDO), which selects optimal CH and performs clustering. In contrast, the CH selection and clustering are performed dynamically by considering time and event metrics, which increases communication efficiency and reduces energy depletion. To reduce energy consumption, This research model performs duty cycling using the Improved Twin Delayed Deep Deterministic Policy Gradient (ITD3) algorithm, increasing the network lifetime. Finally, A secure multipath routing is performed using a game theory-based Generative Adversarial Network (GTGAN). During routing, GTGAN ranks the selected multipath based on their hop counts. The highest-ranked paths are selected for transmitting an emergency message, and medium-ranked paths are selected for non-emergency message transmission, which reduces data loss due to energy depletion. Here, all the transactions are stored on the blockchain for increased security. The NS-3.26 network simulator conducts the simulation of this research, and the performances are evaluated based on various performance metrics, proving that the proposed work achieves superior performance compared to existing works.
The <inline-formula> <tex-math notation="LaTeX">\kappa </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula> / inverse gamma and <inline-formula> ...<tex-math notation="LaTeX">\eta </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula> / inverse gamma composite fading models are presented and extensively investigated in this paper. We derive closed-form expressions for the fundamental statistics of the <inline-formula> <tex-math notation="LaTeX">\kappa </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula> / inverse gamma composite fading model, such as the probability density function (PDF), cumulative distribution function (CDF). Additionally, we solve the associated integral that is commonly used to obtain the moment generating function (MGF) of statistical distributions to provide an MGF-type function which is valid for performance analysis over the specified parameter space. Analytic expressions for the PDF, higher order moments and AF are also derived for the <inline-formula> <tex-math notation="LaTeX">\eta </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula> / inverse gamma composite fading model, while infinite series expressions are obtained for the corresponding CDF and MGF-type function. The suitability of the new models for characterizing composite fading channels is demonstrated through a series of extensive field measurements for wearable, cellular, and vehicular communications. For all of the measurements, two propagation geometry problems with special relevance to the two new composite fading models, namely the line-of-sight (LOS) and non-LOS (NLOS) channel conditions, are considered. It is found that both the <inline-formula> <tex-math notation="LaTeX">\kappa </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula> / inverse gamma and <inline-formula> <tex-math notation="LaTeX">\eta </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula> / inverse gamma composite fading models provide an excellent fit to fading conditions encountered in the field. The goodness-of-fit of these two composite fading models is also evaluated and compared using the resistor-average distance. As a result, it is shown that the <inline-formula> <tex-math notation="LaTeX">\kappa </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula> / inverse gamma composite fading model provides a better fit compared to the <inline-formula> <tex-math notation="LaTeX">\eta </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula> / inverse gamma composite fading model when strong dominant signal components exist. On the contrary, the <inline-formula> <tex-math notation="LaTeX">\eta </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula> / inverse gamma composite fading model outperforms the <inline-formula> <tex-math notation="LaTeX">\kappa </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula> / inverse gamma composite fading model when there is no strong dominant signal component and/or the parameter <inline-formula> <tex-math notation="LaTeX">\eta </tex-math></inline-formula> is not equal to unity, indicating that the scattered wave power of the in-phase and quadrature components of each cluster of multipath are not identical.
With the advantages of non-contact, compatibility, no chemical effect and safety, acoustic levitation of object has great potential to apply in chemistry, biology, medicine field and micro robots. ...Suspension to large particle higher than the half wavelength(<inline-formula> <tex-math notation="LaTeX">0.5\lambda </tex-math></inline-formula>) of sound wave, is a challenge technology in micro-nanoscale manipulation. An increased large quantity probes, double sided and four sided phased array with virtual vortex can provide higher capture power, control ability and stability of particle fixation and the manipulation. However, for a limited confined space, the additional probes and sided phased array emission and receiving device is hard to be established and applied. Additional probes and sided ultrasonic phased array requires higher processing ability of MCU (Micro Control Unit) and the quantities of transducers. Further, multiparticles suspension is rare to be reported. In this study, a relatively simple suspension device of one sided concave spherical transducer array is designed, aiming to levitate a large particle and multi-particles. Based on the one sided acoustic field simulation of ultrasonic array, the optimized structure of open spherical sector (OSS) is constructed to establish levitation device. Experimental platform integrating FPGA controller, amplifier and impedance matching is developed to drive the transducer arrays, where a polystyrene particle with 6 mm (<inline-formula> <tex-math notation="LaTeX">0.71\lambda </tex-math></inline-formula>) diameter is successfully levitated. The virtual twin trap sound pressure of transducer array is measured to evaluate the particle stability. Experiments demonstrate the correctness of virtual twin trap acoustic field analysis, the feasibility in the manipulation to the large particle and multi-particles by acoustic trap.
This paper provides precise performance analysis of the dual-hop mixed radio frequency (RF)/unified free space optical (FSO) decode-and-forward (DF) relaying system, in which the heterodyne detection ...and the intensity modulation-direct detection (IM-DD) are taken into account for FSO detection. To this end, we derive closed-form expressions for the outage probability, average bit error rate (BER), and the ergodic channel capacity of this system. In this analysis, we utilize, for the first time as per our knowledge, a precise channel capacity result for the IM-DD channel. Moreover, this is the first time that not only the (IM-DD input-independent) but also the (IM-DD cost-dependent) additive white Gaussian noise (AWGN) channel is considered in such system analyses. Additionally in this study, we assume that the first hop (RF link) follows Nakagami- m fading, and the second hop (FSO link) follows Málaga ( M ) turbulence with pointing errors. These fading and turbulence models contain other models (such as Rayleigh and Gamma-Gamma) as special cases, thus, our analyses can be seen as a generalized one from the RF and FSO fading models point of view. Also, in BER derivation, we assume that the modulation schemes in the two hops can be different, since not all modulation schemes are suitable for IM-DD FSO links. In addition, the system performance is investigated asymptotically at high signal to noise ratios. This investigation leads to new nonreported coding gain and diversity order analyses of such system. Interestingly, we find that in the FSO hop, at high transmitted powers, all the considered FSO detectors result in the same diversity order. Furthermore, we provide simulation results that verify the accuracy of the obtained analytical and asymptotic expressions.
When it comes to integrating inverter-based resources (IBRs) into modern grids with varying characteristics like unbalanced systems, low-inertia networks, or very weak grids, synthesizing the ...synchronization control method (SCM) of the IBR's phase-locked loop can be a challenging task. This paper provides a unique solution to enhance the three-phase IBR's SCM using the adaptive dynamic programming (ADP) method based on reinforcement learning. By making the SCM more intelligent and self-learning, IBRs can be easily integrated into diverse grids. To this end, this article investigates the synchronization process's detailed dynamics, including all incorporating disturbances and parameters required for the first step in designing the ADP method. Afterward, this research synthesizes an optimal controller using an ADP method. It is a data-driven and practically sound approach to the problem under investigation. The new methodology is based on the adaptive optimal control employing measurement feedback to control the output regulation problem of uncertain synchronization process dynamics via the internal model principle. The proposed SCM design deploys an ADP learning methodology to tackle uncertain parameters and unknown disturbance signals to synchronize IBRs during transients, thereby enhancing IBRs' synchronization in challenging conditions of modern power systems with unbalanced, low-inertia, and very weak grids. For comparison purposes, this paper applies a robust controller based on the well-established <inline-formula> <tex-math notation="LaTeX">\mu</tex-math> </inline-formula> synthesis approach (benefiting from the well-known <inline-formula> <tex-math notation="LaTeX">D\text{-}K</tex-math> </inline-formula> iteration process). Comparative simulations are performed; experiments are conducted to reveal the effectiveness and practicality of the ADP-based optimal SCM proposed in this paper. Note to Practitioners -As different nations strive to combat global warming and accelerate decarbonization, power and energy systems are undergoing a significant shift. Inverter-based resources are being used as an essential component to achieve these goals. However, studies have revealed that designing synchronization control methods of the inverter-based resources' phase-locked loop in unbalanced, low-inertia, and very weak grids is challenging due to the need for accurate dynamic models and other factors. This study revisits the synchronization process's detailed dynamics. It also proposes a novel adaptive dynamic programming strategy using intelligent self-learning approaches to the synchronization control method associated with inverter-based resources. This method utilizes an optimal control to synthesize the adaptive dynamic programming control strategy for the inverter-based resources' synchronization process. Besides, it employs measurement feedback to control the output regulation problem of uncertain dynamics of inverter-based resources' synchronization process via the internal model principle. As a result, this paper makes this process data-driven. It utilizes a learning methodology using adaptive dynamic programming to address uncertain parameters and unknown disturbance signals associated with the dynamics derived and formulated for the problem under investigation. Thus, the proposed method applies to controlling inverter-based resources' synchronization process even in cases with slow parameter variations caused by different factors. It can compensate for all functional disturbance signals affecting the dynamics of the systems. In fact, unlike traditional methods that need an exact dynamic model of the inverter-based resources' synchronization process to design and tune the controller to achieve a proper transient response, the proposed control system trains itself and does so. This study's simulations and experiments reveal that the above points give the proposed approach a competitive edge over the existing methodologies.
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