Sags and swells are types of power quality disturbances that involve fluctuations in voltage. Sags are decreases in a voltage’s magnitude while swells are increases in a voltage’s magnitude. There are a number of di...
Sags and swells are types of power quality disturbances that involve fluctuations in voltage. Sags are decreases in a voltage’s magnitude while swells are increases in a voltage’s magnitude. There are a number of different techniques to identify and classify these power quality disturbances, however in an industrial setting power utilities typically employ the use of the CBEMA and ITIC curves to classify the power quality disturbances they encounter. The CBEMA and ITIC curves utilize RMS voltage to denote whether a disturbance is expected to impact the system it occurs on, however there are a number of ambiguities surrounding the use of both curves. One such ambiguity is the lack of specification surrounding the window size used to calculate RMS values. This paper proposes MATLAB scripts that can synthesize waveforms with sags and swells according to a variety of user-defined parameters and provide their RMS voltages. This paper also presents a MATLAB function that can plot the RMS voltage magnitude and durations of transient events onto the ITIC curve. This paper explores the effect of varying the window size used to calculate RMS voltage for each disturbance across different parameters. Moreover, the paper presents an analysis of the RMS voltage of a real-world voltage sag in a three-phase system.
This paper demonstrates the seamless fabrication of optoelectronic memory by integrating HfSe 2 as a charge-trapping layer in a MOS memory structure. Through a spin coating technique, solution-processable HfSe 2 fla...
This paper demonstrates the seamless fabrication of optoelectronic memory by integrating HfSe 2 as a charge-trapping layer in a MOS memory structure. Through a spin coating technique, solution-processable HfSe 2 flakes with average thicknesses of 2 nm were deposited between the tunneling and blocking oxide layers. The charge-trapping material distribution and thickness were explored by Atomic Force Microscopy and X-ray Diffraction Spectroscopy. The electrical characterization of MOS memory revealed a memory window of 5.5 Volts under ±16 Volts biasing. Furthermore, the memory endurance exceeds 10 4 electricalprogramming and erasing cycles. The retention test performed at room temperature showed that the memory device is expected to lose only 10% of the stored charges after 10 years. Under light stimuli (405nm wavelength and output power ~ 20 mW) with electrical readout voltage, the MOS memory showed an increase in the memory window from 5.5 Volts to 6.5 Volts.
Radio frequency energy harvesting has attracted considerable interest as a technique of enabling self-powered wireless networks. This technique faces several challenges, such as the receiving and the rectifying module...
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Due to the intermittent characteristics of solar radiation, the integration of large-scale photovoltaic (PV) systems into the power grid raises many power quality problems such as voltage drop, unstable grid frequency...
Due to the intermittent characteristics of solar radiation, the integration of large-scale photovoltaic (PV) systems into the power grid raises many power quality problems such as voltage drop, unstable grid frequency, and harmonics. Despite these drawbacks, the integration of large-scale PV systems into the grid definitely has several advantages. This paper investigates the positive impact of integrating large-scale PV systems into the electric power grid. In this study, the PV system contributes 10%-20% of the power to the grid. Load flow analysis based on the Newton Raphson model is used to calculate grid losses when the PV system is connected at different positions along the feeder line. The results showed that there was a decrease in power losses that occurred in the network from 29.4 kW to 29.2 kW when the PV system was injected into the network at the start of the power line. Then losses can be reduced from 29.4 kW to 29.1 kW when the PV system is integrated in the midfield. The reduction in power losses becomes more significant when the PV system is injected at the end of the line from 29.4 to 28.6 kW. In conclusion, integration of the PV system into the power grid can improve the power loss and voltage profile.
Recently, techniques for fabricating micro-sized deep ultraviolet light-emitting diodes (DUV LEDs) have been gaining attention. In this work, we propose a selective thermal oxidation (STO) process to fabricate ultra-s...
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Recently, techniques for fabricating micro-sized deep ultraviolet light-emitting diodes (DUV LEDs) have been gaining attention. In this work, we propose a selective thermal oxidation (STO) process to fabricate ultra-small DUV micro-LEDs. Annealed in the air at 900°C for 2 h, the p-layers without SiO 2 protection are oxidized into insulating oxides, and oxygen penetrates into parts of the quantum wells. In contrast, the patterned SiO 2 protects the LED structure in the pixel regions. Therefore, micro-LED pixels are formed by the patterned SiO 2 and thermal oxidation process rather than the conventional reactive ion etching. The formed oxide in the unprotected region can function as the insulation layer between p–n electrodes. Meanwhile, the boundary between the pixel and the surrounding oxide is naturally formed during thermal oxidation, which is a “self-aligned” process. Dielectric deposition, precise lithography alignment, and aperture etching in the conventional process are no longer required in STO-based micro-LED fabrication, which reduces production complexity and cost. Based on the STO process, we have achieved 2.3-µm DUV micro-LED standalone pixels and arrays with a 270-nm emission wavelength. The standalone DUV micro-LED is possibly the smallest reported in the literature to date, which has a low-operation voltage of 4.9 and 6.75 V at 10 and 1000 A/cm 2 . Meanwhile, the fabricated DUV micro-LED arrays show leakage current density 4 × 10 −7 A/cm 2 at −5 V and a peak EQE of 0.77% under unpackaged conditions. We hope this work provides a new insight into micro-LED fabrication and further promotes future performance growth of DUV LEDs.
This study is related to a system that enables elderly people to communicate interactively with young people who use existing message exchange services by simply speaking to an avatar on a tablet PC, without having to...
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We report a simple, vacuum-compatible fiber attach process for in situ study of grating-coupled photonic devices. The robustness of this technique is demonstrated on grating-coupled waveguides exposed to multiple X-ra...
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ISBN:
(纸本)9798350369311
We report a simple, vacuum-compatible fiber attach process for in situ study of grating-coupled photonic devices. The robustness of this technique is demonstrated on grating-coupled waveguides exposed to multiple X-ray irradiations for aerospace studies.
As a novel 2D material, MoS 2 has shown excellent electrical properties and resistive switching characteristics to work as a switching layer for non-volatile memory. In this work, we drop cast the MoS 2 solution to ...
As a novel 2D material, MoS 2 has shown excellent electrical properties and resistive switching characteristics to work as a switching layer for non-volatile memory. In this work, we drop cast the MoS 2 solution to prepare the thin film and deposit an interfacial layer of Al 2 O 3 . We demonstrate the proposed memristive device with Cu/Al 2 O 3 /MoS 2 /Pt structure to work as an artificial synapse. The device shows a steady resistive switching behavior with the SET and RESET voltages of 1.3 V and -0.5 V, respectively. We further demonstrate the synapse behavior via a Hopfield Neural Network (HNN) and achieve image recognition and reconstruction with a high accuracy of 96% after 15 training epochs.
A discontinuous Galerkin time-domain scheme is formulated and implemented to analyze three-dimensional transient lasing dynamics. The proposed scheme solves a coupled system of the Maxwell and the rate equations. The ...
A discontinuous Galerkin time-domain scheme is formulated and implemented to analyze three-dimensional transient lasing dynamics. The proposed scheme solves a coupled system of the Maxwell and the rate equations. The atomic transitions through different energy levels are quantum-mechanically described by a four-level two-electron model, while the electro-magnetic interactions are treated using the Maxwell equations. The resulting solver accounts for the Pauli Exclusion Principle and permits robust simulation of lasing dynamics under optical pumping. Numerical results are presented to demonstrate the applicability and the accuracy of the proposed scheme.
In this research study, we compare the predictive performance of two advanced deep learning-based models in order to provide a solution to TACE (Transarterial Chemoembolization) response prediction in HCC (Hepatocellu...
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