scholarly journals Numerical Study of Plasmonic Efficiency of Gold Nanostripes for Molecule Detection

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Thomas Grosges ◽  
Dominique Barchiesi
Keyword(s):  
Finite Element Method ◽  
Electromagnetic Field ◽  
Numerical Study ◽  
Field Enhancement ◽  
Field Amplitude ◽  
Geometrical Parameters ◽  
Error Estimator ◽  
Optimization Scheme ◽  
Electromagnetic Excitation ◽  
Active Zones

In plasmonics, the accurate computation of the electromagnetic field enhancement is necessary in determining the amplitude and the spatial extension of the field around nanostructures. Here, the problem of the interaction between an electromagnetic excitation and gold nanostripes is solved. An optimization scheme, including an adaptive remeshing process with error estimator, is used to solve the problem through a finite element method. The variations of the electromagnetic field amplitude and the plasmonic active zones around nanostructures for molecule detection are studied in this paper taking into account the physical and geometrical parameters of the nanostripes. The evolution between the sizes and number of nanostripes is shown.

scholarly journals Dilation of nanonatennas induced by an electromagnetic source

2012 ◽  
Vol 1 (2) ◽  
pp. 48 ◽  
Author(s):  
D. Barchiesi ◽  
E. Kremer ◽  
A. Cherouat ◽  
T. Grosges ◽  
H. Borouchaki
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Electromagnetic Field ◽  
Field Enhancement ◽  
Fine Tuning ◽  
Adaptive Meshing ◽  
Mechanical Effects ◽  
The Relationship ◽  
Metallic Nanorods ◽  
Electromagnetic Source

The illumination of plasmonic mesostructures produces high confinement of light in their vicinity. This confinement of light can be enhanced in the gap between the two metallic nanorods of a nanonantenna, in particular for the design of biosensors. The nanometric gap can be reduced if the elevation of temperature of the nanonantenna is sufficient, and therefore the fine tuning of the sensor requires the description of the photo-thermal induced dilation. The multiphysics problem associated to such photo-thermal and mechanical effects is modeled through a Finite Element Method (FEM). The problem consists in computing the electromagnetic field, the temperature and the induced dilation surface. This contribution consists in discussing the numerical efficiencies of a sequential, and a coupled approaches, especially in terms of adaptive meshing of the space of computation. The relationship between the field enhancement and the reduction of the gap is studied. Finally the validity of the 2D multiphysic model is discussed.

INVESTIGATION OF DEPENDENCE IMPACT OF TOOL GEOMETRICAL PARAMETERS AND CUTTING SPEED UPON SHAPING EFFORT AT HELICAL GROOVE CUTTING ON INTERNAL SURFACE OF CYLINDRICAL SHELL

2020 ◽  
Vol 2020 (10) ◽  
pp. 22-28
Author(s):  
Vadim Kuc ◽  
Dmitriy Gridin
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cylindrical Shell ◽  
Contact Interaction ◽  
Cutting Speed ◽  
Internal Surface ◽  
Geometrical Parameters ◽  
Software Complex ◽  
Helical Groove ◽  
Groove Cutting

The work purpose was the investigation of dependence impact of tool geometrical parameters upon shaping effort during internal groove cutting. As a realization for the fulfillment of the helical groove processing investigation there was used a software complex based on a finite element method and a computer mathematic system. As a result of the investigations carried out there was obtained a regression equation manifesting the dependence of factors impact upon axial force falling on one tooth of the tool in the set scale of factor parameters. The scientific novelty consists in that in the paper there is considered a new method for helical groove cutting in which a shaping motion is carried out at the expense of the contact interaction of a tool and a billet performing free cutting. The investigation results obtained allowed determining the number of teeth operating simultaneously, that can be used further at cutting mode setting, and also as recommendations during designing tool design.

scholarly journals Numerical Study on the Surface Plasmon Resonance Tunability of Spherical and Non-Spherical Core-Shell Dimer Nanostructures

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1728
Author(s):  
Joshua Fernandes ◽  
Sangmo Kang
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Surface Plasmon Resonance ◽  
Aspect Ratio ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Shell Thickness ◽  
Numerical Study ◽  
Field Enhancement ◽  
Core Shell

The near-field enhancement and localized surface plasmon resonance (LSPR) on the core-shell noble metal nanostructure surfaces are widely studied for various biomedical applications. However, the study of the optical properties of new plasmonic non-spherical nanostructures is less explored. This numerical study quantifies the optical properties of spherical and non-spherical (prolate and oblate) dimer nanostructures by introducing finite element modelling in COMSOL Multiphysics. The surface plasmon resonance peaks of gold nanostructures should be understood and controlled for use in biological applications such as photothermal therapy and drug delivery. In this study, we find that non-spherical prolate and oblate gold dimers give excellent tunability in a wide range of biological windows. The electromagnetic field enhancement and surface plasmon resonance peak can be tuned by varying the aspect ratio of non-spherical nanostructures, the refractive index of the surrounding medium, shell thickness, and the distance of separation between nanostructures. The absorption spectra exhibit considerably greater dependency on the aspect ratio and refractive index than the shell thickness and separation distance. These results may be essential for applying the spherical and non-spherical nanostructures to various absorption-based applications.

Numerical study of the geometrical parameters on CH4/air premixed combustion in heat recirculation micro-combustor

Fuel ◽  
2015 ◽  
Vol 159 ◽  
pp. 45-51 ◽  
Author(s):  
Yunfei Yan ◽  
Wenli Pan ◽  
Li Zhang ◽  
Weimin Tang ◽  
Yanrong Chen ◽  
...  
Keyword(s):  
Numerical Study ◽  
Premixed Combustion ◽  
Geometrical Parameters ◽  
Heat Recirculation ◽  
Micro Combustor

Local Hydrostatic Pressure Test for Cylindrical Vessels

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
H. Al-Gahtani ◽  
A. Khathlan ◽  
M. Sunar ◽  
M. Naffa'a
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Hydrostatic Pressure ◽  
Cylindrical Vessel ◽  
Geometrical Parameters ◽  
The Finite Element Method ◽  
Wide Range ◽  
Pressure Test ◽  
Local Test ◽  
Alternative Test

The juncture of a small cylindrical nozzle to a large cylindrical vessel is very common in the pressure vessel industry. Upon fabrication, it is required that the whole structure is subjected to pressure testing. The test can be expensive as it necessitates pressurizing the whole structure typically having a large volume. Hence, it is proposed to make a “local test,” which is considerably simpler as it involves capping the small nozzle and testing only a relatively small portion of the structure. This paper investigates the accuracy and reliability of such an alternative test, using the finite-element method. Two different finite-element types are used in the study, specifically a shell-based element and a solid-based element. The verification of the finite-element results for two different cases shows that the models used in the study are valid. It also proves that the two element types yield very similar stress results. In addition, the study includes a numerical investigation of more than 40 different nozzle-to-vessel junctures with a wide range of parameters for the nozzle and vessel. The results indicate that the use of cylindrical caps that are slightly larger than the nozzle is not recommended as it produces stresses that are significantly different from those for the original required pressure test. As such, the study provides an estimate of the smallest size of the cap that may be used in the local test to generate stresses that agree with the full test. For most practical geometries, it is shown that the size of the cap needs to be at least 2–30 times larger than that of the nozzle, depending on the geometrical parameters of the juncture.

scholarly journals Numerical study of Fisher's equation by a Petrov-Galerkin finite element method

1991 ◽  
Vol 33 (1) ◽  
pp. 27-38 ◽  
Author(s):  
S. Tang ◽  
R. O. Weber
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Study ◽  
Galerkin Finite Element Method ◽  
Linear Diffusion ◽  
Galerkin Finite Element ◽  
Fisher’S Equation ◽  
Nonlinear Reaction ◽  
Fisher's Equation ◽  
Element Method

AbstractFisher's equation, which describes a balance between linear diffusion and nonlinear reaction or multiplication, is studied numerically by a Petrov-Galerkin finite element method. The results show that any local initial disturbance can propagate with a constant limiting speed when time becomes sufficiently large. Both the limiting wave fronts and the limiting speed are determined by the system itself and are independent of the initial values. Comparing with other studies, the numerical scheme used in this paper is satisfactory with regard to its accuracy and stability. It has the advantage of being much more concise.

scholarly journals Study on surface enhanced Raman scattering of Au and Au@Al2O3 spherical dimers based on 3D finite element method

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bao-xin Yan ◽  
Yan-ying Zhu ◽  
Yong Wei ◽  
Huan Pei
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Electric Field ◽  
Raman Scattering ◽  
Enhancement Factor ◽  
Field Enhancement ◽  
Electric Field Enhancement ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

AbstractIn this paper, the surface enhanced Raman scattering (SERS) characteristics of Au and Au@Al2O3 nanoparticle dimers were calculated and analyzed by using finite element method (3D-FEM). Firstly, the electric field enhancement factors of Au nanoparticles at the dimer gap were optimized from three aspects: the incident angle of the incident light, the radius of nanoparticle and the distance of the dimer. Then, aluminum oxide is wrapped on the Au dimer. What is different from the previous simulation is that Al2O3 shell and Au core are regarded as a whole and the total radius of Au@Al2O3 dimer is controlled to remain unchanged. By comparing the distance of Au nucleus between Au and Au@Al2O3 dimer, it is found that the electric field enhancement factor of Au@Al2O3 dimer is much greater than that of Au dimer with the increase of Al2O3 thickness. The peak of electric field of Au@Al2O3 dimer moves towards the middle of the resonance peak of the two materials, and it is more concentrated than that of the Au dimer. The maximum electric field enhancement factor 583 is reached at the shell thickness of 1 nm. Our results provide a theoretical reference for the design of SERS substrate and the extension of the research scope.

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