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- 摘要
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- 实验方案
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[IEEE 2019 IEEE Conference on Antenna Measurements & Applications (CAMA) - Kuta, Bali, Indonesia (2019.10.23-2019.10.25)] 2019 IEEE Conference on Antenna Measurements & Applications (CAMA) - Development of a Wideband Substrate Integrated Waveguide Bandpass Filter Using H-Slotted DGS
摘要： In the current work, a new Wideband Substrate Integrated Waveguide Bandpass Filter (SIW-BPF) is presented. The target is to allow vertical roaming between the X and Ku band applications. As a first step, we performed a parametric study of different etched slot geometries namely, H-Slotted, T-Slotted, and U-Slotted DGS in order to examine the effects of altering different geometrical parameters of the unit on its response. H-Slotted DGS shows the highest FBW with 82.89% on the average compared to other geometries. As a second step, the cell size and the numbers of the H-Slotted DGS were optimized with the use of finite element method with the following constraints taken into consideration: low cost fabrication, high Q-Factor, compact size and easy integration. One of the designs was chosen for fabrication to validate the designed circuit. The measured results show that our optimized filter achieves an insertion loss of 2.01 dB at 8.5 GHz, a return loss higher than 11 dB and fractional bandwidth of 90.87% for a single cell and a fractional bandwidth of 80.05% for multiple cells. The measured results are in good agreement with the simulated results.
关键词： Substrate Integrated Waveguide (SIW),Finite Element Method,Ku-Band,Bandpass filter (BPF),Electromagnetic Band Gap structure (EBG),Wideband,X-Band
更新于2025-09-23 15:21:01
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Three-core photonic crystal fiber surface plasmon resonance sensor
摘要： A three-core photonic crystal fiber (PCF) surface plasmon resonance (SPR) biosensor with high performance is presented. The structure of the biosensor is easy to implement and has good repetition. The outer layer of the fiber structure is gold film. The analyte is placed on the surface of the gold film. The Full vector finite element method is used to numerical simulation and analysis the transmission mode and characteristics of the three-core PCF-SPR biosensor. The influence of sensor structure parameters on sensing performance is investigated. The structure parameters are optimized. The optimum structure parameters are given. The refractive index (RI) sensitivity of the sensor is discussed there. The results show that the average refractive index sensitivity of the sensor is 3435 nm/RIU in the sensing range of 1.33–1.40, and the resolution is 2.91 × 10?6 RIU. The sensor has the advantages of high sensitivity and high resolution. And it can be applied to real-time detection of the bio-molecules and small drug-molecules.
关键词： Photonic crystal fiber,Biosensor,Surface plasmon resonance,Refractive index sensitivity,Finite element method
更新于2025-09-23 15:21:01
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A 0.5-T pure-in-plane-field magnetizing holder for in-situ Lorentz microscopy
摘要： A side-entry specimen holder capable of applying a 0.5-tesla in-plane magnetic-induction field for in-situ transmission electron microscopy was developed. Three miniaturized electromagnets with 300 × 300-μm pole area and 180-μm pole gap are stacked along the electron-beam path in the holder. The middle magnet is used for magnetizing the specimen, which is inserted into the pole gap by using a 40-μm-width cantilever for atomic-force microscopy. The upper and lower magnets are used to keep the electron beam parallel to the optical axis. Magnetic-field magnitude was determined on the basis of experimentally measured electron-deflection angles and induction-field profiles along the electron-beam path calculated by finite element electromagnetic simulation. Magnetization reversal in 300-nm-thick Nd-Fe-B magnets from the saturated state was in-situ observed by using the holder and a 1-MeV cold-field-emission transmission electron microscope. The observation revealed that domain-wall pinning occurred in different manners at the c-plane and non-c-plane grain boundaries. The holder was thereby shown to be useful for analysis of magnetization-reversal behaviors of hard magnetic materials.
关键词： In situ transmission electron microscopy,Specimen holder,Magnetic domains,Finite element method,Lorentz microscopy,Hard magnetic material
更新于2025-09-23 15:21:01
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[IEEE 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Chengdu, China (2018.3.26-2018.3.28)] 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - High-Order Ultra-Weak Variational Formulation for Maxwell Equations
摘要： The ultra-weak variational formulation (UWVF) is a Trefftz method for solving time-harmonic wave problems. The combination of flexible meshing and the use of plane wave basis functions makes the UWVF well-suited for solving Maxwell problems in inhomogeneous media and in general geometries that can be tens or even hundreds wavelengths. In a single mesh, the number of basis functions can be adjusted element-wise based on the element size, material properties in the element and the requested level accuracy of the solution. Previous studies have shown that the UWVF method can use from 3 to 130 plane waves per element. In this study, the use of high-dimensional plane waves basis for the UWVF is investigated. The aim is to find a basis which would allow elements with h/λ ≈ 10 (where h is the length of the longest edge of the element and λ is the wavelength). Three methods for choosing the directions of the plane waves are compared in terms of accuracy of the UWVF approximation and the conditioning of the resulting matrix system. Results suggest that in a simple model problem the goal is achievable but requires over 500 plane wave basis functions per element for a tolerable accuracy.
关键词： Maxwell equations,Finite element method
更新于2025-09-23 15:21:01
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Nuclear Power Plant Prestressed Concrete Containment Vessel Structure Monitoring during Integrated Leakage Rate Testing Using Fiber Bragg Grating Sensors
摘要： As the last barrier of nuclear reactor, prestressed concrete containment vessels (PCCVs) play an important role in nuclear power plants (NPPs). To test the mechanical property of PCCV during the integrated leakage rate testing (ILRT), a fiber Bragg grating (FBG) sensor was used to monitor concrete strain. In addition, a finite element method (FEM) model was built to simulate the progress of the ILRT. The results showed that the strain monitored by FBG had the same trend compared to the inner pressure variation. The calculation results showed a similar trend compared with the monitoring results and provided much information about the locations in which the strain sensors should be installed. Therefore, it is confirmed that FBG sensors and FEM simulation are very useful in PCCV structure monitoring.
关键词： structure health monitoring (SHM),finite element method (FEM),integrated leakage rate test (ILRT),fiber Bragg grating (FBG),prestressed concrete containment vessel (PCCV)
更新于2025-09-23 15:21:01
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[IEEE 2018 International Conference on Recent Innovations in Electrical, Electronics & Communication Engineering (ICRIEECE) - Bhubaneswar, India (2018.7.27-2018.7.28)] 2018 International Conference on Recent Innovations in Electrical, Electronics & Communication Engineering (ICRIEECE) - Processing of Silicon Heterojunction Solar Cell and Its Secondary Ion Mass Spectrometric Characterization
摘要： A new numerical technique to solve nonlinear systems of initial value problems for nonlinear first-order differential equations (ODEs) that model genetic networks in systems biology is developed. This technique is based on finding local Galerkin approximations on each sub-interval at a given time grid of points using piecewise hat functions. Comparing the numerical solution of the new method for a single nonlinear ODE with an exact solution shows that this method gives accurate solutions with relative error 1.88 × 10?11 for a time step 1 × 10?6. This new method is compared with the adaptive Runge Kutta (ARK) method for solving systems of ODEs, and the results are comparable for a time step 2 × 10?4. It is shown that the relative error of the Galerkin method decreases approximately linearly with the log of the number of hat functions used. Unlike the ARK method, this new method has the potential to be parallelizable and to be useful for solving biological problems involving large genetic networks. An NSF commissioned video illustrating how systems biology helps us understand that a fundamental process in cells is included.
关键词： hat function,Galerkin method,systems biology,ordinary differential equation,finite element method,toggle switch,Newton–Raphson method,Biological clock
更新于2025-09-23 15:19:57
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Numerical simulation of selective laser melting with local powder shrinkage using FEM with the refined mesh
摘要： A mathematical model of selective laser melting (SLM) of fine-grained metallic powders under the pulse laser annealing conditions has been developed. The processed powder bed is considered in the approximation of continuous medium where its effective thermophysical properties depend on local porosity. The model allows simulation of unsteady distributions of temperature, specific enthalpy, local porosity, morphology and thickness of the processed track. In the paper, all stages of problem analysis are described including its mathematical formulation and numerical implementation. To take into account shrinkage of the powder layer during sintering and remelting, the numerical model utilizes the arbitrary Lagrangian–Eulerian (ALE) method. Thus the finite element mesh provides robust control of quality and dynamic remeshing through adaptive mesh refinement. Using the proposed numerical model the unsteady thermal fields and local porosity of a Fe-based powder layer processed with a pulsed laser has been investigated.
关键词： numerical simulation,adaptive mesh refinement,finite element method,selective laser melting,powder shrinkage
更新于2025-09-23 15:19:57
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Application of Plasmonic Nanoantennas in Enhancing the Efficiency of Organic Solar Cells
摘要： It is known that the periodic use of silver nanoantennas in organic solar cells increases the e?ciency of light absorption. In this study, we performed a geometric parametric analysis of nanoantennas using the ?nite element method. Based on the study of the convex truncated cone nanoantenna, we have found that a nanoantenna arrangement formed by the convex truncated cone nanoantenna along with a pyramidal nanoantenna provides a better solution for di?erent angles of light incidence compared to a single nanoantenna. We obtained a mean increase in the absorption e?ciency of this organic solar cell, both for the TM and TE polarizations, compared to the use of the conventional nanoantenna in the wavelength range of 300–800 nm.
关键词： convex truncated cone nanoantenna,organic solar cells,finite element method,pyramidal nanoantenna,plasmonic nanoantennas,light absorption
更新于2025-09-23 15:19:57
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Analysis of a Single Solid Core Flat Fiber Plasmonic Refractive Index Sensor
摘要： In this article, a single solid core flat fiber (SSCFF) refractive index sensor based on surface plasmon resonance (SPR) is proposed and analyzed numerically using the finite element method (FEM). The proposed flat fiber consists of a single array of five circular holes. Among them the central hole is made of GeO2-doped silica which is forming the core. Other holes are filled with air and situated symmetrically on both sides of the central solid core. The upper flat surface of the fiber is coated with a thin plasmonic gold layer which is protected by an active titanium dioxide layers. Analyte is situated on top of these layers. The wavelength interrogation technique is applied to study the coupling characteristics between the core-guided mode and the surface plasmon mode as well as for the refractive index measurement. Numerical analysis results show that this sensor is able to detect high refractive index analytes from 1.49 to 1.54 with a good linear response. Additionally, the dependence of surface plasmonic resonance wavelength on analyte refractive index is studied. The maximum wavelength sensitivity of this sensor is found to be 4782 nm/RIU with a high resolution of 2.09 × 10?5 RIU. The effects of different structural parameters on loss spectrum are studied in detail to optimize this SSCFF structure. In comparison to traditional PCF, this SSCFF structure is fabrication complexity free as well as a suitable candidate for developing portable devices and high refractive index analyte sensors, particularly chemical and protein sensors.
关键词： Photonic crystal fiber,Surface plasmon,Optical sensing,Finite element method,Refractive index sensor
更新于2025-09-23 15:19:57
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Intrinsic-strain-induced curling of free-standing two-dimensional Janus MoSSe quantum dots
摘要： Motivated by the fascinating properties of both two-dimensional transition metal dichalcogenide quantum dots (TMD QDs) and Janus TMD monolayers, we theoretically explore the equilibrium structures of free-standing Janus MoSSe QDs in which atomic asymmetry of chalcogen is introduced. Two distinct types of spontaneous curling are observed by molecular dynamics simulations, and the curling behavior depends on the size of QD. The bowl-like (tube-like) curling occurs in relatively small (large) MoSSe QDs with di?erent shapes (hexagon and triangle) and edge types (zigzag and armchair). The transition between these two curling types occurs at the sizes of around 10 nm and 13 nm for hexagonal and triangular shapes, respectively. By applying equivalent mis?t strains into two adjacent sublayers, ?nite element analysis reproduces similar curling behavior. This con?rms the relaxation of intrinsic strain in Janus structure acting as the predominant driving force of spontaneous curling. In addition, the curvatures of Janus TMD QDs increase from MoSSe to MoSeTe to MoSTe, indicating the positive correlation between the curling and mis?t.
关键词： Intrinsic strain,Janus transition metal dichalcogenides,Molecular dynamics,Quantum dot,Finite element method
更新于2025-09-23 15:19:57