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Plasmonic nickel nanoparticles decorated on to LaFeO3 photocathode for enhanced solar hydrogen generation
摘要： Plasmonic Ni nanoparticles were incorporated into LaFeO3 photocathode (LFO-Ni) to excite the surface plasmon resonances (SPR) for enhanced light harvesting for enhancing the photoelectrochemical (PEC) hydrogen evolution reaction. The nanostructured LFO photocathode was prepared by spray pyrolysis method and Ni nanoparticles were incorporated on to the photocathode by spin coating technique. The LFO-Ni photocathode demonstrated strong optical absorption and higher current density where the untreated LFO film exhibited a maximum photocurrent of 0.036 mA/cm2 at 0.6 V vs RHE, and when incorporating 2.84 mmol Ni nanoparticles the photocurrent density reached a maximum of 0.066 mA/cm2 at 0.6 V vs RHE due to the SPR effect. This subsequently led to enhanced hydrogen production, where more than double (2.64 times) the amount of hydrogen was generated compared to the untreated LFO photocathode. Ni nanoparticles were modelled using Finite Difference Time Domain (FDTD) analysis and the results showed optimal particle size in the range of 70e100 nm for Surface Plasmon Resonance (SPR) enhancement.
关键词： LaFeO3,Finite difference time domain,Surface plasmon resonance,Ni nanoparticle,Photocathode,Photoelectrochemical water splitting
更新于2025-10-22 19:40:53
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Preparation and optical properties of angle-dependent photonic crystals based on multi-layer films
摘要： The CreSiO2 photonic crystals, featured with two-dimensional structure and optical variation, was prepared by magnetron sputtering and electron beam lithography method. The finite difference time domain method (FDTD) is used to study the light-modulated characteristics of photonic crystals. Hue difference (⊿H) was used to evaluate the optical variations of photonic crystals, and bigger ⊿H indicates stronger angle dependency of color variation. Various parameters are analyzed for their impact upon ⊿H, including hole geometry (radium, r), hole gap (distance between the centers of two circles, d) and hole depth (h). The results matched the ones from simulation. Carbon quantum dots and up-conversion nanocrystals NaYF4 were inserted into the photonic crystals, and testing results of these doped crystals showed optical variation of fluorescence in the UV and IR region.
关键词： Finite difference time domain,Multi-layer films,Photonic crystal,Optical variability
更新于2025-09-23 15:23:52
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Numerical study of nanoscale biosensor based on surface plasmon polariton propagation in Mach-Zehnder interferometer structure
摘要： In this paper, we numerically investigate a nanoscale plasmonic biosensor based on Mach-Zehnder interferometry. The operation of Mach-Zehnder interferometer (MZI) biosensor is examined based on two methods. In the first method, in which the transmission of surface plasmon polariton (SPP) modes is investigated under different refractive indices of sample medium as well as different dimensions, the best transmission rate achieved about 56.6% which is resulted by refractive index variation about 0.045 for the length 12 μm and width 80 nm of the gold layer. Also, the sensitivity, figure of merit (FOM) and quality factor (Q-factor) of MZI are examined for different geometries by utilizing the alternative method. It is realized that for the constant length, increasing the thickness of gold layer has significantly led to increased Q-factor and FOM. On the other hand, considering fixed thickness of the Au layer and three different lengths, the major outcome is that as the length of biosensor increases, the sensitivity, Q-factor as well as FOM follow an upward trend. Finally, inserting two distinct additional gold layers on top of the main gold layer, resulted in an extreme increase for the sensitivity and FOM of the plasmonic MZI biosensors with respect to the MZI biosensor without additional layer.
关键词： Plasmonic biosensor,Surface plasmon polariton (SPP),Mach-Zehnder interferometer (MZI),Finite difference time domain (FDTD)
更新于2025-09-23 15:23:52
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UPML-ABC of dispersive materials for the unconditionally stable 2-D WLP-FDTD method
摘要： In this paper, uniaxial anisotropic perfectly matched layer (UPML) absorbing boundary condition (ABC) of dispersive materials is presented for 2-D finite-difference time-domain (FDTD) method with weighted Laguerre polynomials (WLP). Taking advantage of the auxiliary differential equation (ADE) technique, our proposed algorithm avoids not only the complicated formulations but also the convolution integral. Using ADE scheme, the relationship between field components and auxiliary differential variables is derived in Laguerre domain. Substituting auxiliary differential variables into UPML-ABC, the electric field E of order q can be expressed directly by magnetic field H in Laguerre domain. Inserting magnetic field H of order q into electric field, and using central difference scheme, the formulations of uniaxial anisotropic dispersive media PML are obtained. One numerical example of wave propagation in 2-D dispersive materials is simulated. Numerical results validate the efficiency of the presented method.
关键词： finite-difference time-domain (FDTD),weighted laguerre polynomials (WLP),uniaxial anisotropic dispersive materials,perfectly matched layer (PML),Auxiliary differential equation (ADE)
更新于2025-09-23 15:23:52
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Finite-Difference Time-Domain Modeling for Electromagnetic Wave Analysis of Human Voxel Model at Millimeter-Wave Frequencies
摘要： The finite-difference time-domain (FDTD) modeling of a human voxel model at millimeter-wave (mmWave) frequencies is presented. It is very important to develop the proper geometrical and electrical modeling of a human voxel model suitable for accurate electromagnetic (EM) analysis. Although there are many human phantom models available, their voxel resolution is too poor to use for the FDTD study of EM wave interaction with human tissues. In this paper, we develop a proper human voxel model suitable for mmWave FDTD analysis using the voxel resolution enhancement technique and the image smoothing technique. The former can improve the resolution of the human voxel model and the latter can alleviate staircasing boundaries of the human voxel model. Quadratic complex rational function is employed for the electrical modeling of human tissues in the frequency range of 6–100 GHz. Massage passing interface-based parallel processing is also applied to dramatically speed up FDTD calculations. Numerical examples are used to illustrate the validity of the mmWave FDTD simulator developed here for bio electromagnetics studies.
关键词： human tissue,electromagnetic wave,Doppler radar,dispersion model,bioelectromagnetics,Finite-difference time-domain (FDTD) method,parallel processing
更新于2025-09-23 15:23:52
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[IEEE 2018 International Symposium on Electronics and Telecommunications (ISETC) - Timisoara, Romania (2018.11.8-2018.11.9)] 2018 International Symposium on Electronics and Telecommunications (ISETC) - Investigation of Wave Propagation in a Plasma Antenna using 3D FDTD
摘要： The advancement of computer technology has led numerical methods to obtain a widespread usage. One of the most frequently used numerical methods in recent years is finite difference time domain method (FDTD). The behaviour of electromagnetic waves at the boundaries of the problem space has been studied by using perfectly matched layer (PML) type boundary conditions in FDTD.On the other hand, the majority of the substances in the universe are plasma. Plasma is a well known reconfigurable medium with different dielectric and conductive properties. Operating frequency of a plasma antenna is investigated in this paper. The field distributions around the plasma antenna have been evaluated using three dimensional FDTD. It has been shown that the plasma antenna can operate with characteristics similar to a wire antenna. C/C++ and MATLAB programming environments are used for simulations.
关键词： Finite Difference Time Domain,perfectly matched layer,plasma antenna
更新于2025-09-23 15:22:29
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B-scan wave outline analysis in numerical modeling of ground-penetrating radar response from layered rough interfaces
摘要： Imaging of rough interfaces in a layered structure requires full understanding of the characteristics of their ground penetrating radar (GPR) echoes. In this study, a finite-difference time-domain computational model using a uniaxial perfectly matched layer boundary for GPR demining of layered rough interfaces is constructed. On the basis of this model, the numerical results of B-scan echoes from two-layered and three-layered rough interfaces with different degrees of roughness are obtained and compared with the profiles of corresponding rough surfaces. These results and comparisons highlight the relationship between the B-scan wave outlines and the profile of the layered rough interfaces. The effect of roughness of the interface on the B-scan echoes are analyzed, and the influence of the upper rough surface profile on the shape of the B-scan wave outline from the lower rough surface is discussed.
关键词： layered rough interfaces demining,finite-difference time-domain method (FDTD),ground penetrating radar (GPR),echo characteristic analysis
更新于2025-09-23 15:22:29
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A Theoretical Extension of AH FDTD Method and Applications in Various Physical Fields
摘要： In this paper we extended the Associated Hermite (AH) FDTD method theoretically and used it to analyze various physical fields, which are electromagnetic field, acoustic field and heat-transfer field. The AH differential transformation operator is developed theoretically as a basic element for setting a time-frequency bridge, where several common operators such as differential, second-order differential and integral linear operator, etc. on the concept of signal processing and analyzing can be expediently transformed, which leads to a unified and much simpler derivation to construct the previous AH FDTD formula. Therefore, it gives a reconsideration for AH FDTD to calculate a more general or even arbitrary liner physic field problems, which are focused on the commonly partial differential equations. Finally, based on the time-frequency bridge theory, we adopted several examples for verification from the formula derivation to numerical validation in electromagnetic field, acoustic field and heat-transfer field, respectively.
关键词： Acoustic,Heat-transfer,Associated Hermite,Finite difference time domain (FDTD)
更新于2025-09-23 15:22:29
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One-Step Leapfrog HIE-FDTD for Drude Media
摘要： A one-step leapfrog hybrid implicit–explicit finite-difference time-domain (HIE-FDTD) method is developed for Drude dispersive media. The Drude media is modeled through a current source characterized by a semi-implicit auxiliary differential equation. The stability condition is the same as that of conventional leapfrog HIE-FDTD and is determined by the grid cell size along only one direction. The proposed method is used to efficiently investigate the properties of surface plasmon polaritons propagating along a one-atom-thick graphene sheet in low terahertz band with a very fine grid.
关键词： Drude dispersive media,graphene,hybrid implicit–explicit finite-difference time-domain method,one-step leapfrog,stability
更新于2025-09-23 15:22:29
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RESEARCH ON MINIMUM ENERGY EXCITED TO PLASMA COATING FOR REDUCING RADAR CROSS SECTION OF TARGET
摘要： To reduce the radar cross section (RCS) of a target, plasma coating on perfectly electric conducting plate is studied in this paper. Nonuniform helium plasma produced by a minitype solid rocket engine is with collisional and unmagnetized. Energy excited for generating helium plasma is investigated. Based on the collisional, unmagnetized, and cold plasma model, backscattering RCS is computed by using ?nite-di?erence time-domain method. Principle of RCS reduction is explained. To ?nd minimum input energy while RCS reduced, relationship between input power and RCS reduction is discussed, and numerical optimization is also implemented. We can identify optimal parameters and choose the best electron density pro?le under condition of given input power level.
关键词： Radar Cross Section (RCS),Plasma Coating,Input Power,Electron Density,Finite-Difference Time-Domain (FDTD) Method
更新于2025-09-23 15:21:21