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Topological and nontopological photonic states in two coupled circuit quantum electrodynamics chains
摘要： We investigate the topological and nontopological photonic states induced by the interchain coupling strength in a one-dimensional coupled circuit quantum electrodynamics chains system. In the case of strong coupling strength, we find that the original topologically nontrivial interface states of the system gradually disappear and finally become two nontopological impurity states. Meanwhile, two new topologically nontrivial interface states appear next to the two middle resonators. The processes can be clearly delineated by the energy eigenvalue spectrum and the state distributions of the system. Moreover, we present the phase diagram to illustrate the characteristics of phase transition of the system. Assisted by the lattice-based cavity input-output process, we can measure these photonic states, which are either localized or extended, in the steady state condition. Our scheme would be feasible for experimental implementation of topological and nontopological photonic states with the current physical system.
关键词： topological phase,circuit quantum electrodynamics,nontopological impurity state,Su–Schrieffer–Heeger model
更新于2025-09-23 15:19:57
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Circuit Topology Analysis for LED Lighting and its Formulation Development
摘要： Light emitted diode (LED) is becoming more popular in the illumination field, and the design of LED lighting is generally made to provide illumination at lower power usage, helping save energy. A power electronic converter is needed to provide the power conversion for these LEDs to meet high efficiency, reduce components, and have low voltage ripple magnitude. The power supply for LED is revisited in this paper. The LEDs connected in series with diode, transistor, or inductor paths are examined. The formulation for each of the cases is described, including the classical converters of buck, boost, buck–boost, and ′Cuk. The circuit reductions of the classic circuit, circuit without the capacitor, and without a freewheeling diode are studied. Using LED to replace freewheeling diodes is proposed for circuit component reduction. General equations for different connection paths have been developed. The efficiency and output ripple amplitude of the proposed power converters are investigated. Analytical study shows that the efficiency of proposed circuits can be high and voltage ripple magnitude of proposed circuits can be low. The results show that the proposed circuit topologies can be easily adapted to design LED lighting, which can meet the criteria of high efficiency, minimum components, and low-voltage ripple magnitude at the same time.
关键词： LED driving circuit,component count,diode path,efficiency,ripple amplitude,inductor path,theoretical analysis,transistor path
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Investigating metal-semiconductor contacts in solar cells using magnetic field measurements
摘要： While solar cells and modules are already a mature technology in mass production, contacting schemes are constantly evolving. For example, multi busbar/multi wire contacting systems are currently being developed. During the development and the production of such technologies, it is critical to optimize and to systematically monitor their performance. In this paper, we find that different contacting fault types can be identified by inducing specific current flow patterns through the contacts of a single side of a solar cell and measuring the resultant 2D magnetic field image. Additionally, we explore the use of circuit network modelling in conjunction with these magnetic field images to gain further insights about the contacting schemes. Excellent agreement between circuit simulations and magnetic field measurements was achieved by combining different current flow patterns as demonstrated on a multi-wire contacted solar cell.
关键词： photovoltaic cells,circuit modelling,characterization,magnetic field measurements,SPICE
更新于2025-09-23 15:19:57
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Electromagnetic Physical Numerical Modeling of a GaN Distributed Transferred Electron Devicea??Based Planar Waveguide THz Oscillator
摘要： The radio frequency (RF) operation of a planar waveguide THz oscillator based on the distributed transferred electron device (DTED) is theoretically investigated by means of 2-D time-domain numerical physical modeling based on the self-consistent solution of the Maxwell and free electron energy-momentum macroscopic transport equations.
关键词： circuit design analysis,distributed transferred electron device (DTED),2-D time-domain electromagnetic physical numerical modeling,planar waveguide THz oscillator
更新于2025-09-23 15:19:57
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A New Strategy for Increasing the Efficiency of Inverted Perovskite Solar Cells to More than 21%: Higha??Humidity Induced Selfa??Passivation of Perovskite Films
摘要： The performance of perovskite solar cells (PSCs) are known to be extremely sensitive to humidity in the preparation environment. However, the main mechanism by which the moisture influences the quality of the perovskite film and the device performance is not yet completely revealed. In this work, we established a new strategy to obtain inverted PSCs with remarkable high VOC by including a high-humidity treatment and sufficient DMSO-atmosphere annealing in the preparation process. We found that the lattice distortion on the surface of perovskite grains caused by the high-humidity treatment played a key role in the self-passivation of perovskite. Inverted (p-i-n) PSCs based on the self-passivated perovskite films showed effective suppression of non-radiative recombination, which increased the device VOC to 1.17 V and achieved the highest efficiency of 21.38 %. It is expected that the findings of this work shed more light on the currently proposed mechanism governing the action of moisture on the performance of the PSCs.
关键词： Self-passivation,High open-circuit voltage,Perovskite solar cells,High-humidity,Grain boundaries
更新于2025-09-23 15:19:57
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Machine Learning Based Approaches for Modeling the Output Power of Photovoltaic Array in Real Outdoor Conditions
摘要： It is important to investigate the long‐term performances of an accurate modeling of photovoltaic (PV) systems, especially in the prediction of output power, with single and double diode models as the configurations mainly applied for this purpose. However, the use of one configuration to model PV panel limits the accuracy of its predicted performances. This paper proposes a new hybrid approach based on classification algorithms in the machine learning framework that combines both single and double models in accordance with the climatic condition in order to predict the output PV power with higher accuracy. Classification trees, k‐nearest neighbor, discriminant analysis, Na?ve Bayes, support vector machines (SVMs), and classification ensembles algorithms are investigated to estimate the PV power under different conditions of the Mediterranean climate. The examined classification algorithms demonstrate that the double diode model seems more relevant for low and medium levels of solar irradiance and temperature. Accuracy between 86% and 87.5% demonstrates the high potential of the classification techniques in the PV power predicting. The normalized mean absolute error up to 1.5% ensures errors less than those obtained from both single‐diode and double‐diode equivalent‐circuit models with a reduction up to 0.15%. The proposed hybrid approach using machine learning (ML) algorithms could be a key solution for photovoltaic and industrial software to predict more accurate performances.
关键词： prediction of performances,PV modules modeling,classification algorithms,equivalent‐circuit models,machine learning
更新于2025-09-23 15:19:57
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Analytical Methods of Equivalent Circuit Model and Transmission Matrix for a Plasmonic Switch with Sensing Capability in Near-Infrared Region
摘要： In this paper, the simultaneous switching and sensing capabilities of a compact plasmonic structure based on a conventional rectangular hole in a silver film are proposed and investigated. The proposed structure has ultrahigh sensitivity up to 3000 nm/RIU and high figure of merit of 170 RIU?1. Also, the simulation results show the potential of the presented refractive index sensor to detect malaria infection, cancer cells, bacillus bacteria, and solution of glucose in water. Simultaneously, by changing the incident lightwave polarization, the structure behaves like a plasmonic switch, which has high extinction ratios of 15.81, 31.20, and 25.03 dB at three telecommunication wavelengths of 850, 1310, and 1550 nm, respectively. The ultrafast response time of 20 fs is achieved for the wideband application of the switching capability at the wavelength range of 1056 to 1765 nm. Moreover, the equivalent circuit model and transmission (ABCD) matrix methods are derived to validate the simulated results. Simple design, good agreement between the numerical and analytical results, biomedical applications, ultrahigh sensitivity, and ultrafast performance of the proposed structure help this idea to open up paths for design and implementation of other multi-application plasmonic devices in near-infrared region. To the best of our knowledge, the mentioned analytical methods have not been studied former at near-infrared wavelengths. Therefore, the achievements could pave the way for verifying the simulation results of plasmonic nanostructures in future investigations.
关键词： Near-infrared,Switch,Circuit model,Transmission matrix,Sensor,Biomedical,Polarization-multiplexing,Plasmonic
更新于2025-09-23 15:19:57
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[IEEE 2018 11th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - HangZhou, China (2018.9.5-2018.9.7)] 2018 11th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - High-Efficiency Transmission-Type Digital Coding Metasurface for Metalens and Transmitarray
摘要： Field-programmable gate arrays (FPGAs) have been shown to provide high computational density and efficiency for many computing applications by allowing circuits to be customized to any application of interest. FPGAs also support programmability by allowing the circuit to be changed at a later time through reconfiguration. There is great interest in exploiting these benefits in space and other radiation environments. FPGAs, however, are very sensitive to radiation and great care must be taken to properly address the effects of radiation in FPGA-based systems. This paper will highlight the effects of radiation on FPGA-based systems and summarize the challenges in deploying FPGAs in such environments. Several well-known mitigation methods will be described and the unique ability of FPGAs to customize the system for improved reliability will be discussed. Finally, two case studies summarizing successful deployment of FPGAs in radiation environments will be presented.
关键词： radiation effects,radiation hardening,field programmable gate arrays,integrated circuit reliability,Fault-tolerant systems
更新于2025-09-23 15:19:57
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Improving open-circuit voltage by a chlorinated polymer donor endows binary organic solar cells efficiencies over 17%
摘要： Power conversion efficiency (PCE) of single-junction polymer solar cells (PSCs) has made a remarkable breakthrough recently. Plenty of work was reported to achieve PCEs higher than 16% derived from the PM6:Y6 binary system. To further increase the PCEs of binary OSCs incorporating small molecular acceptor (SMA) Y6, we substituted PM6 with PM7 due to the deeper highest occupied molecular orbital (HOMO) of PM7. Consequently, the PM7:Y6 has achieved PCEs as high as 17.0% by the hot-cast method, due to the improved open-circuit voltage (VOC). Compared with PM6, the lower HOMO of PM7 increases the gap between ELUMO-donor and EHOMO-acceptor, which is proportional to VOC. This research provides a high PCE for single-junction binary PSCs, which is meaningful for device fabrication related to PM7 and commercialization of PSCs.
关键词： binary system,power conversion efficiencies,open-circuit voltage,single junction
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE CHILEAN Conference on Electrical, Electronics Engineering, Information and Communication Technologies (CHILECON) - Valparaiso, Chile (2019.11.13-2019.11.27)] 2019 IEEE CHILEAN Conference on Electrical, Electronics Engineering, Information and Communication Technologies (CHILECON) - A sustainability-based comparison between Photovoltaics and Concentrating Solar Power in Chile
摘要： This paper investigates the downlink of a single-cell base station (BS) equipped with a large-scale antenna array system while considering a non-negligible transmit circuit power consumption. This consumption involves that activating all RF chains does not always necessarily achieve the maximum sum-rate when the total BS transmit power is limited. This paper formulates a sum-rate maximization problem when a low complexity linear precoder, such as conjugate beamforming or zero forcing beamforming, is used. The problem is first relaxed by assuming arbitrary antenna selection. In this case, we derive analytically the optimal number of activated RF chains that maximizes the sum-rate under either optimal power allocation or equal received power constraint for all users. Also, user scheduling algorithms are proposed when users require a minimum received signal-to-interference-plus-noise ratio. Two iterative user scheduling algorithms are designed. The first one is efficient in terms of fairness and the second one achieves the optimal performance. Next, the antenna selection is investigated and we propose iterative antenna selection algorithms that are efficient in terms of instantaneous sum-rate. Simulation results corroborate our analytical results and demonstrate the efficiency of the proposed algorithms compared with arbitrary and optimal brute force search antenna selection.
关键词： circuit power consumption,Large-scale MIMO,power allocation,user scheduling,antenna selection
更新于2025-09-23 15:19:57