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[IEEE 2017 International Renewable and Sustainable Energy Conference (IRSEC) - Tangier (2017.12.4-2017.12.7)] 2017 International Renewable and Sustainable Energy Conference (IRSEC) - Simulation. Testing and Implementation of a Phase Locked Loop Used to Control a PV - Micro- Inverter
摘要： Phase, amplitude and frequency of the utility grid are critical parameters for the operation of the grid-connected power conditioning equipments. In such applications, an accurate and fast detection of the phase angle of the utility voltage is essential to insure a correct generation of the reference signals. This paper mainly focuses on the simulation, test and the implementation of a specific Phase Locked Loop “inverse Park transformation PLL” that is used to control a PV-Micro-Inverter. The improvement consists of better harmonics filtering. Experimental results validate the effectiveness of the proposed method.
关键词： PV-Micro-Inverter,Simulation,Test,Phase Locked Loop,Implementation
更新于2025-09-10 09:29:36
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Modeling of Quench Behavior of YBa<formula><tex>$_{2}$</tex></formula>Cu<formula><tex>$_{3}$</tex></formula>O<formula><tex>$_{7-\delta}$</tex></formula> Pancake Magnets and Distributed Temperature Sensing-based Quench Detection for Operating Temperature 30 K - 77 K
摘要： A two-dimensional/three-dimensional (2-D/3-D) mixed electrothermal model is proposed for the simulation of quench behavior of high-temperature superconducting (HTS) pancake magnets, where a 2-D electrothermal model is proposed to simulate the YBa2 Cu3 O7 -δ (YBCO) subcoil and is coupled with the remaining parts of the YBCO magnet, which are treated as 3-D homogeneous coils. For operating temperature from 30 to 77 K, the quench behavior of four YBCO pancake coils (two Kapton-insulated coils and two TiO2 -insulated coils) are simulated. Thermal equilibrium states are found for both Kapton- and TiO2 -insulated coils. The thermal conductivity of insulating materials (Kapton, TiO2 ) significantly affects the equilibrium temperature profiles (ETPs) and the minimum quench energy (MQE), especially for relatively high operating temperature (e.g., 65–77 K). The distributed-temperature-sensing-based (DTS-based) quench detection criterion can be established on ETPs. The effect of the thickness of insulating materials on ETPs and MQEs is relatively weak, especially under relatively low operating temperature. The key parameters of ETP-based quench detection criterion, such as the reference temperature, the peak temperature, and the minimum normal zone size, are obtained for the operating temperature from 30 to 77 K.
关键词： quench detection criterion,Distributed temperature sensing (DTS),high-temperature superconducting (HTS) magnet,quench simulation,minimum quench energy (MQE)
更新于2025-09-10 09:29:36
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Tensile mechanical properties and fracture behavior of monolayer InSe under axial tension
摘要： Based on a newly developed interatomic potential, the mechanical properties and fracture behavior of monolayer InSe are investigated by using the classical molecular dynamics method. We ?nd that monolayer InSe exhibits excellent mechanical properties comparing with other two-dimensional materials. Especially, it can sustain an axial tensile strain of 27% in the zigzag direction at room temperature 300 K. Furthermore, the numerical results indicate that the monolayer InSe has an isotropy in the mechanical behaviors with the Youngs modulus being about 43 N/m both in the armchair and zigzag directions. We also discuss the e?ects of temperature and strain rate on the mechanical properties of monolayer InSe and ?nd the high temperature-sensitivity. It’s found that the mechanical properties signi?cantly decrease as the increasing temperature. In contrast, the mechanical properties has a relatively weak dependence on the strain rate. As the strain rate increases from 0.0002 to 0.0008 ps?1, Young’s modulus nearly keeps a constant. The fracture stress and strain in armchair direction only increase by 3.6% and 8.3%, respectively.
关键词： Tensile strain,Monolayer InSe,Molecular dynamics simulation,Two-dimensional materials,Mechanical property
更新于2025-09-10 09:29:36
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Performance evaluation of total variation (TV) denoising technique for dual-energy contrast-enhanced digital mammography (CEDM) with photon counting detector (PCD): Monte Carlo simulation study
摘要： The dual-energy contrast-enhanced digital mammography (CEDM) system based on a photon counting detector (PCD) is very useful providing functional information for breast cancer detection. In particular, this system can be used to solve the spectral overlap and high radiation dose problems. However, imaging noise is a big problem because of the degradation image performance and cancer detection ratio in the CEDM system. To address this problem, a total variation (TV)-based denoising technique approach has recently been studied. Thus, the aim of this study was to evaluate and confirm the image performance of our TV-based denoising technique with dual-energy CEDM with a PCD. For this purpose, we simulated a dual-energy CEDM with a PCD and breast phantom in Monte Carlo simulation using the Geant4 Application for Tomographic Emission (GATE) that is an essential open source program. We also designed a TV-based denoising technique based on the L1-norm estimation included correction and iteration steps for acquiring high edge preservation in X-ray images. To evaluate the image performance, we used evaluation parameters with a contrast-to-noise ratio (CNR) and coefficient of variation (COV) as a function of the absorbed dose levels (2.18, 1.53, 1.09, and 0.66 mGy). According to the results, the average of all iodine thicknesses and absorbed dose conditions for the CNR using our proposed TV-based denoising technique was 1.71, 1.39, and 1.13 times higher than that acquired for the noisy image, median filter and Wiener filter, respectively. We also acquired excellent COV results for the dual-energy CEDM with a PCD system (2.53 times higher than that of the noisy image). In conclusion, the results of this study suggested that a TV-based denoising technique can be achieved with an improved image performance and the effect and feasibility of the TV-based denoising technique for dual-energy CEDM with a PCD can be investigated.
关键词： Dual-energy imaging method,Monte Carlo simulation,Total variation (TV)-based denoising technique,Photon counting detector (PCD),Evaluation of image performance,Contrast-enhanced digital mammography (CEDM)
更新于2025-09-10 09:29:36
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Computational design of microstructures of textured ferroelectric ceramics by phase field simulation
摘要： Grain-oriented microstructure evolutions of ferroelectric ceramics were analyzed using phase field simulations. In templated grain growth, the coarsening behavior of the template particle was investigated in detail. Although a large grain boundary energy was set in the lateral direction along the casting plane, the template particle grew mainly in the vertical direction and gradually converted from a needle-like to rectangular grain. We demonstrated a critical interval of template particles for the preparation of highly textured ceramics. Therefore, different microstructures with high degrees of texture could be fabricated by adjusting and controlling the template size and fraction. Complementary experiments were guided by the computational design. Dense ferroelectric ceramics with high degrees of texture were obtained.
关键词： Templated grain growth,Ferroelectric ceramic,Textured ceramic,Computer simulation
更新于2025-09-10 09:29:36
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Label-free optical biosensor for target detection based on simulation-assisted catalyzed hairpin assembly
摘要： Taking the advantage of the high selectivity of aptamers and enzyme-free catalyzed hairpin assembly (CHA) amplification strategy, we herein describe a label-free and enzyme-free sensitive fluorescent and colorimetric strategy for amplified thrombin detection in this paper. To support both biological inquiry and technological innovation, thermodynamic models are introduced to predict the minimum energy secondary structure of interacting nucleic acid strands and calculate the partition function and equilibrium concentration for complexes in our system. Then, the thermodynamics properties of interacting DNA strands and the reactions of toehold strand displacement-driven assembly have been simulated, validating the feasibility of the theory and optimizing the follow-up lab tests. Following that, our strategy for thrombin detection is proved to be feasible and effective in biological experiments.
关键词： Computation and simulation,G-quadruplex,catalyzed hairpin assembly,fluorescence biosensor,DNA strand displacement
更新于2025-09-10 09:29:36
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Enhanced photocatalytic H2 evolution and phenol degradation over sulfur doped meso/macroporous g-C3N4 spheres with continuous channels
摘要： S-doped meso/macroporous g-C3N4 spheres (SMCN) were successfully synthesized via an in situ novel method utilizing millimeter-scale porous silica spheres as template and thiourea as precursor and S source. Such SMCN possessed millimeter-scale spherical morphology with continuous channels at 20e80 nm in the interior of the spheres, and exhibited increased H2 generation rate (15 times) and phenol degradation rate (5 times) under visible light irradiation compared with that over pristine g-C3N4, mainly due to the enlarged surface area, enhanced mass transfer and improved ef?ciency of charges separation all stemming from the synergetic effects of the S doping and pore creating. Notably, density functional theory (DFT) calculations were employed to further understand the mechanism of the photocatalytic enhancement with regard to the optical absorption property at atomic level. Combined with the ?nite difference time domain (FDTD) simulations aiming at evaluating the effect of the nanoscale pore architecture on the optical absorption ability, it was revealed that not only the S doping but also the meso/macroporous structure resulted in the enhancement of the optical absorption, which was considered to be an essential role for the enhanced photocatalytic performances over SMCN.
关键词： Continuous channels,FDTD simulation,Optical absorption,DFT,S-doping
更新于2025-09-10 09:29:36
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Scratching of silicon surfaces
摘要： Nanoscale scratching of silicon surfaces is the elementary abrasive event for various machining techniques including fixed abrasive wiresaw slicing, grinding, elliptical ultrasonic cutting and single-point diamond turning. The understanding of this process is essential for improving the surface quality and reducing sub-surface damage. Nanoscratching experiments are performed using a well characterized diamond tip geometry. The finite element method is employed in order to simulate the scratching process with a continuum constitutive model developed for phase transformation in silicon (Budnitzki, M., Kuna, M., 2016. Stress induced phase transitions in silicon. JMPS 95, 64–91). The required material parameters were determined from indentation experiments in a (111) single crystal Si wafer. The simulation results agree very well with data from scratch experiments without requiring additional calibration.
关键词： silicon,scratching,phase transition,grinding,wiresawing,simulation
更新于2025-09-10 09:29:36
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[IEEE 2018 International Conference on Information , Communication, Engineering and Technology (ICICET) - Pune, India (2018.8.29-2018.8.31)] 2018 International Conference on Information , Communication, Engineering and Technology (ICICET) - Simulation of Dual Axis Solar Tracking System
摘要： Photovoltaic (PV) panel is used to convert solar energy into electricity. Increase in collection of solar radiations by Photovoltaic (PV) panel rises electricity output from it. By tracking the movement of sun, PV panel can be always positioned in such a way that it can collect maximum amount of solar radiations. This paper presents MATLAB simulation model of Dual Axis Solar Tracking System (DASTS), in which the PV panel can be rotated along two axes of rotation to track both east to west and north to south movement of sun. East to west angle selector and north to south angle selector provide particular angles to PV panel according to particular illuminance level at particular time of the day to rotate and position PV panel in such a way that it can always faces the sun. Readings of voltage, current and power obtain from PV panel with Dual Axis Solar Tracking System are taken at different times of the day and they are compared with readings of voltage, current and power obtain from fixed PV panel at different times of the day.
关键词： Modeling and simulation,Photovoltaic (PV) module,Angle selector
更新于2025-09-10 09:29:36
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - High-Bandwidth Organic Light Emitting Diodes for Ultra-Low Cost Visible Light Communication Links
摘要： Visible light communications (VLC) have attracted considerable interest in recent years due to an increasing need for data communication links in home and enterprise environments. Organic light-emitting diodes (OLEDs) are widely used in display applications owing to their high brightness, high quality colour-rending capability and low cost. As a result, they are attractive candidates for the implementation of ultra-low cost visible light optical links in free-space and guided-wave communications. However, OLEDs need to exhibit a bandwidth of at least ~MHz to be able to support the modest data rates (~Mbps) required in these applications. Although fluorescent OLEDs typically exhibit shorter photon lifetimes than inorganic LEDs, the bandwidth performance of the large size OLEDs used in display applications are limited by their electrical characteristics. In this work, we present a detailed physical simulation that describes well the performance of fast OLED devices that exhibit significant -3 dB bandwidths (f3dB) of 44 MHz obtained for a 0.12 mm2 device. It is demonstrated that the reduction of the device size results in a significant bandwidth improvement due primarily to a reduction in parasitic capacitance of the devices, though this is counteracted by carrier dynamic effects. The model provides an insight into the basic physical properties of the OLED and may be used for optimisation of future generations of OLED devices.
关键词： simulation,visible light communications,modelling,OLED
更新于2025-09-10 09:29:36