AN ADVANCED OPTIMIZATION TECHNIQUE FOR LAYER-SPECIFIC CHARACTERIZATION OF SLAB METAMATERIALS

2013 ◽  
Vol 24 (04) ◽  
pp. 1350019 ◽  
Author(s):  
OLEG RYBIN
Keyword(s):  
Open Source ◽  
Minimization Problem ◽  
Relative Permittivity ◽  
Software Package ◽  
Effective Medium Theory ◽  
Optimization Technique ◽  
Medium Theory ◽  
Permittivity And Permeability ◽  
Definition Of

A new optimization technique for evaluating the complex effective relative permittivity and permeability of elementary sub-slab whose thickness equals to the constant of a unit cell of a slab metamaterial is developed. The objective of the technique is based on a numerical solving of appropriate minimization problem for a cascaded network representation of the slab metamaterial utilizing the Effective Medium Theory (EMT) and the definition of S- and T-parameters of the metamaterials considered as a four-pole network. The technique is tested using the open source FDTD software package and the optimization technique obtained [O. Rybin and M. Raza, Int. J. Appl. Electrom. Mech.32, 207 (2010)].

Preparation and Characterization of Molybdenum Disulfide Microcrystals in Colloidal Dispersion

1989 ◽  
Vol 164 ◽  
Author(s):  
E. Lu ◽  
P. D. Persans ◽  
A. F. Ruppert ◽  
R. R. Chianelli
Keyword(s):  
Optical Constants ◽  
Phonon Mode ◽  
Laser Excitation ◽  
Effective Medium Theory ◽  
Organic Liquid ◽  
Colloidal Dispersion ◽  
Medium Theory ◽  
Resonant Raman ◽  
Resonant Raman Scattering

AbstractWe report the preparation and general, optical and resonant Raman scattering characterization of MoS2 platelets suspended in an insulating organic liquid. Structural results indicate that the platelets are predominantly 2H in structure and are about 500Å in diameter and 50–90 Å thick. The optical constants of the composite are close to those expected from the simple Maxwell-Garnett effective medium theory. We have observed resonant enhancement of the Raman cross-section for the MoS2 phonon mode at 408 cm−1 as the laser excitation energy is scanned through the “B” exciton.

Characterization of porous indium tin oxide thin films using effective medium theory

2003 ◽  
Vol 93 (2) ◽  
pp. 984-988 ◽  
Author(s):  
J. Ederth ◽  
G. A. Niklasson ◽  
A. Hultåker ◽  
P. Heszler ◽  
C. G. Granqvist ◽  
...  
Keyword(s):  
Thin Films ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Effective Medium Theory ◽  
Effective Medium ◽  
Oxide Thin Films ◽  
Medium Theory

Elastic moduli of anisotropic clay

Geophysics ◽  
2007 ◽  
Vol 72 (5) ◽  
pp. D107-D117 ◽  
Author(s):  
Irina O. Bayuk ◽  
Mike Ammerman ◽  
Evgeni M. Chesnokov
Keyword(s):  
Clay Minerals ◽  
Effective Medium Theory ◽  
Optimization Technique ◽  
Transversely Isotropic ◽  
Effective Medium ◽  
Stiffness Tensor ◽  
Medium Theory ◽  
Inversion Technique ◽  
Water Saturated

Clay minerals are important components in shales, controlling their elastic properties and anisotropy. The elasticity of crystalline clay minerals differs significantly from that of clay in situ because of the ability of clay particles to bind water. In the ma-jority of published works, only isotropic moduli for in situ clays are reported. However, anisotropy is inherent in the clay elas-ticity. We develop an inversion technique for determination of the stiffness tensor of in situ clay from the shale’s stiffness tensor. As an example, we obtain the stiffness tensor of a “water-clay” composite from the data on the water-saturated Greenhorn shale sample, whose clay composition consists of almost equal amounts of illite and smectite and comparable amounts of kaolinite and chlorite. The stiffness tensor of the water-clay composite is found for the Greenhorn shale with step-by-step inversion based upon an effective medium theory. The inversion usesa nonlinear optimization technique with bounds imposed on the estimated parameters. In the inversion, we apply different approaches of the effective medium theory using a published method referred to here as the generalized singular approxi-mation (GSA). The GSA method makes it possible to take into account the microstructure of shales. The resulting elasticity constants of the anisotropic (transversely isotropic) in situ clay composite are [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] (in GPa); and the density equals [Formula: see text]. The Thomsen parameters for the clay composite are [Formula: see text], [Formula: see text], and [Formula: see text]. The elasticity constants found for this clay composite can be used in the theoretical analysis of shales that have a similar composition of clay but with different mineral compositions. The inversion technique developed can be used for general shale water-clay composites when the mineral composition and orientation of the clay platelets are known.

Characterization of Plasma-Deposited Au/Fluoropolymer Nanocomposite Films for Nonlinear Optical Application

1998 ◽  
Vol 544 ◽  
Author(s):  
D. Dalacu ◽  
A. P. Brown ◽  
J. E. Klemberg-Sapieha ◽  
L. Martinu ◽  
M. R. Wertheimer ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Optical Model ◽  
Volume Fraction ◽  
Effective Medium Theory ◽  
Gold Nanoclusters ◽  
Nanocomposite Films ◽  
Microstructural Characteristics ◽  
Gold Target ◽  
Medium Theory

AbstractNanocomposite films consisting of gold nanoclusters embedded in a fluorocarbon matrix were prepared by simultaneous plasma polymerization of a fluorocarbon gas and magnetron sputtering of a gold target. The optical constants of the films were determined using variable angle spectroscopic ellipsometry (VASE). The Maxwell-Garnett (M-G) effective medium theory (EMT) was used to extract the microstructural characteristics (gold volume fraction, cluster size). The predictions of the M-G EMT were compared with the results from x-ray photoelectron spectroscopy. Angle-resolved measurements suggest the presence of a carbonaceous layer at the cluster surface. The presence of such a layer is discussed in the context of its influence on the validity of the optical model

scholarly journals OCTAVA: An open-source toolbox for quantitative analysis of optical coherence tomography angiography images

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261052
Author(s):  
Gavrielle R. Untracht ◽  
Rolando S. Matos ◽  
Nikolaos Dikaios ◽  
Mariam Bapir ◽  
Abdullah K. Durrani ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Quantitative Analysis ◽  
Open Source ◽  
Optical Coherence Tomography Angiography ◽  
Microvascular Disease ◽  
Maximum Intensity Projection ◽  
Optical Coherence ◽  
Definition Of ◽  
User Friendly

Optical coherence tomography angiography (OCTA) performs non-invasive visualization and characterization of microvasculature in research and clinical applications mainly in ophthalmology and dermatology. A wide variety of instruments, imaging protocols, processing methods and metrics have been used to describe the microvasculature, such that comparing different study outcomes is currently not feasible. With the goal of contributing to standardization of OCTA data analysis, we report a user-friendly, open-source toolbox, OCTAVA (OCTA Vascular Analyzer), to automate the pre-processing, segmentation, and quantitative analysis of en face OCTA maximum intensity projection images in a standardized workflow. We present each analysis step, including optimization of filtering and choice of segmentation algorithm, and definition of metrics. We perform quantitative analysis of OCTA images from different commercial and non-commercial instruments and samples and show OCTAVA can accurately and reproducibly determine metrics for characterization of microvasculature. Wide adoption could enable studies and aggregation of data on a scale sufficient to develop reliable microvascular biomarkers for early detection, and to guide treatment, of microvascular disease.

The application of effective-medium theory for the nondestructive characterization of ceramic composites

2007 ◽  
Vol 27 (2-3) ◽  
pp. 1071-1076 ◽  
Author(s):  
Vladimir B. Bregar ◽  
Darja Lisjak ◽  
Andrej Žnidaršič ◽  
Miha Drofenik
Keyword(s):  
Effective Medium Theory ◽  
Ceramic Composites ◽  
Effective Medium ◽  
Medium Theory ◽  
Nondestructive Characterization

Effective medium theory characterization of Au/Ag nanoalloy-porous alumina composites

1997 ◽  
Vol 9 (1-8) ◽  
pp. 571-574 ◽  
Author(s):  
G.L. Hornyak ◽  
C.J. Patrissi ◽  
E.B. Oberhauser ◽  
C.R. Martin ◽  
J-C Valmalette ◽  
...  
Keyword(s):  
Effective Medium Theory ◽  
Porous Alumina ◽  
Effective Medium ◽  
Medium Theory ◽  
Alumina Composites

Stress Path Dependent Hydromechanical Properties of Carbonates - Impact of Heterogeneities and use of Effective Medium Theory for Critical State Scaling

2009 ◽  
Author(s):  
Nicolas F. Gland ◽  
Jeremie Dautriat ◽  
Olga Vizika ◽  
Alexandre Dimanov ◽  
Jean L. Raphanel
Keyword(s):  
Critical State ◽  
Effective Medium Theory ◽  
Stress Path ◽  
Effective Medium ◽  
Medium Theory ◽  
Path Dependent
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