The accurate modeling of frequency-dispersive materials is a challenging task, especially when a scheme with a transient nature is utilized, as it is the case of the finite-difference time-domain method. In this work, a novel implementation for the modeling of graphene-oriented dispersive materials via the piecewise linear recursive convolution scheme, is introduced, while the time-varying conductivity feature is, additionally, launched. The proposed algorithm is employed to design a reduced graphene-oxide antenna operating at 6 GHz.
View Article and Find Full Text PDFA novel type of dual concentric core photonic crystal fiber (PCF) is proposed and theoretically analyzed, aiming at the design of tunable dispersive fiber elements for polarization-mode-dispersion (PMD) compensation. The adjustment of the fiber's geometrical birefringence through the proper selection of structural parameters leads to very high values of differential group-delay (DGD). Moreover, the value of DGD can be dynamically tuned by infiltrating the outer core capillaries of the PCF with an optical liquid, which allows for the thermal control of its refractive index.
View Article and Find Full Text PDFComput Methods Biomech Biomed Engin
April 2011
Both the forward and inverse problems of electrocardiography rely on the precise modelling of the anatomic and electrical properties of the thoracic tissues. This, in turn, requires good knowledge of the electrical anisotropy as well as conductivity inhomogeneity of the heart, lungs and the rest of the thorax. Cardiac electrical anisotropy is related to its microstructure (fibre length, density and orientation).
View Article and Find Full Text PDFJ Opt Soc Am A Opt Image Sci Vis
October 2009
We introduce and develop a new explicit vector beam propagation method, based on the iterated Crank-Nicolson scheme, which is an established numerical method in the area of computational relativity. The proposed approach results in a fast and robust method, characterized by simplicity, efficiency, and versatility. It is free of limitations inherent in implicit beam propagation methods, which are associated with poor convergence or uneconomical use of memory in the solution of large sparse linear systems, and thus it can tackle problems of considerable size and complexity.
View Article and Find Full Text PDFIn cardiac transplantation has been recognized some "abnormalities" in recipient ECG. We investigated the influence of heart geometrical position within the chest cavity as well as somatometric parameters on body surface torso potentials. Two control patients with different Body Mass Index (BMI) were undergone a chest MRI scan.
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