Search results for "electromagnetism"
showing 10 items of 276 documents
Estudio del tamaño de cristalito en porcelanas industriales.
2016
El objetivo de la presente tesis en el estudio mediante técnicas de difracción de rayos X, con el apoyo en microscopía electrónica, de la microestructura de la mullita que se desarrolla en porcelanas industriales de formulación triaxial (caolín, feldespato y cuarzo). La porcelana es un material de gran importancia en la industria debido a su uso en campos tecnológicamente muy diversos, tales como la cerámica ornamental, pavimento y revestimiento, aisladores eléctrico o piezas resistentes a agentes físicos y químicos tales como material de laboratorio o partes de motores. Pese a estas características tecnológicas la porcelana ha sido poco estudiada desde el punto de vista científico, si bien…
Relativistic Hydrodynamics and Spectral Evolution of GRB Jets
2017
En la presente tesis hemos estudiado los sistemas progenitores de las erupciones de rayos gamma (ERG, o GRBs por sus siglas en inglés --Gamma-Ray Bursts--) de larga duración mediante modelos numéricos de su evolución dinámica y emisión electromagnética. De todas las posibles clases de eventos, en particular nos centramos en aquellas que muestran una componente prominente de emisión térmica, la cual podría generarse por medio de la interacción de un chorro constituido por plasma relativista con el medio en el que se propaga. La parte central de esta tesis se ha dedicado al modelado de ERG a partir de dos clases diferentes de progenitores: ERG ultra largas dominadas en su espectro de emisión …
Novel architectures and materials for perovskite opto‐electronics
2018
Photovoltaic and light emitting devices based on perovskites have shown an impressive development in the last years. Despite the fast progress, many studies relied still on a trial and error approach in order to further boost device efficiencies. The aim of the thesis is therefore to get further inside into phenomena related to the fundamental photophysics on both perovskite solar cells and LEDs. The work has been structured in three parts: Perovskite‐Perovskite Homojunctions via Compositional Doping. One of the most important properties of semiconductors is the possibility to control their electronic properties via intentional doping. Nevertheless doping in perovskite remains nearly unexpl…
Applet de Física. Polarización lineal: Ley de Malus.
2012
Quan un feix de llum incideix sobre un conjunt de dos o més polaritzadors lineals la intensitat transmesa, que depèn de l'angle relatiu entre ells, es pot expressar mitjançant la llei de Malus. En aquesta simulació es pot veure l'efecte sobre la intensitat del feix incident de l'actuació d'un, dos i fins a tres polaritzadors lineals, dels quals podem seleccionar el seu nombre i variar l'orientació del seu eix de transmissió, comprovant d'aquesta manera el compliment de la llei de Malus. Cuando un haz de luz incide sobre un conjunto de dos o más polarizadores lineales la intensidad transmitida, que depende del ángulo relativo entre ellos, se puede expresar mediante la ley de Malus. En esta s…
Spectral rigidity and invariant distributions on Anosov surfaces
2014
This article considers inverse problems on closed Riemannian surfaces whose geodesic flow is Anosov. We prove spectral rigidity for any Anosov surface and injectivity of the geodesic ray transform on solenoidal 2-tensors. We also establish surjectivity results for the adjoint of the geodesic ray transform on solenoidal tensors. The surjectivity results are of independent interest and imply the existence of many geometric invariant distributions on the unit sphere bundle. In particular, we show that on any Anosov surface $(M,g)$, given a smooth function $f$ on $M$ there is a distribution in the Sobolev space $H^{-1}(SM)$ that is invariant under the geodesic flow and whose projection to $M$ i…
Fibrous Nanozyme Dressings with Catalase-Like Activity for H2O2 Reduction To Promote Wound Healing
2017
The concentrations of the redox pair hydrogen peroxide (H2O2) and oxygen (O2) can promote or decelerate the progression and duration of the wound healing process. Although H2O2 can reach critically high concentrations and prohibit healing, a sufficient O2 inflow to the wound is commonly desired. Herein, we describe the fabrication and use of a membrane that can contemptuously decrease H2O2 and increase O2 levels. Therefore, hematite nanozyme particles were integrated into electrospun and cross-linked poly(vinyl alcohol) membranes. Within the dual-compound membrane, the polymeric mesh provides a porous scaffold with high water permeability and the nanozymes act as a catalyst with catalase-li…
Efficient analysis of in-line waveguide filters and frequency-selective surfaces with stepped holes
2003
This paper presents a novel method for the analysis of large classes of microwave and mm-wave passive components, including in-line waveguide filters, single- and multi-layer frequency selective surfaces, and open-ended waveguide array antennas. This method is based on the segmentation technique, which permits us to reduce complex components to cascaded waveguide step discontinuities, which are separately characterized through their generalized impedance matrices, as calculated by the integral equation (IE) technique and the boundary integral-resonant mode expansion (BI-RME) method. Some examples demonstrate the flexibility and efficiency of the IE/BI-RME method, and its utility in investig…
Excitation of surface plasmon polaritons guided mode by Rhodamine B molecules doped in PMMA stripe
2010
In this letter we show the inclusion of Rhodamine B molecules (RhB) inside a dielectric-loaded surface plasmon waveguide enables for a precise determination of its optical characteristics. The principle relies on the coupling of the fluorescence emission of the dye to plasmonic waveguided modes allowed in of the structure. Using leakage radiation microscopy in real and reciprocal spaces, we measure the propagation constant of the mode and as well as their attenuation length.
Leakage radiation microscopy of surface plasmon coupled emission: investigation of gain-assisted propagation in an integrated plasmonic waveguide.
2010
International audience; Using a single-mode dielectric-loaded surface plasmon polariton waveguide doped with quantum dots, we were able to slightly increase the propagation length of the mode by stimulated emission of plasmon. We analyse the amplification phenomenon in the visible range by combining leakage radiation microscopy and surface plasmon coupled emission techniques.
Modeling propagation for high-power cylindrical microwave applicators
2001
In this letter, the dispersion characteristics and energy configurations of a cylindrical partially filled waveguide or lossy multilayered rod shielded by a metallic enclosure are presented for several modes. These parameters are obtained by a numerical simulation based on the residues theory. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 192–195, 2001.