ELECTROMAGNETIC WAVES

Author: GOMEZ GOMEZ ALVARO.
Year: 2004.
University: CANTABRIA [www.unican.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: In this paper an analysis of the electromagnetic structures in three dimensions (3D) formed by different rectangular waveguides partially filled with half biisótropo. The analysis is done in the first place, obtaining the electromagnetic field in a uniform rectangular guide in the direction of propagation of energy (z direction) through the method of coupled modes (MMA). It was formulated and discussed in depth three formulations of the MMA: two calls FormulacioneS EH and the third formulation called EB. The second part gets widespread scattering matrix (MSG) that characterizes a 3D, using the adaptive mode (MAM).

Author: AMAT GENÍS ALBERTO.
Year: 2004.
University: ROVIRA I VIRGILI [www.urv.cat].
Place of defense: FACULTAT DE MEDICINA I CIÈNCIES DE LA SALUT.
Place of preparation: FACULTAT DE MEDICINA I CIÈNCIES DE LA SALUT.

Summary: ATP is a key molecule in cellular metabolism. In this thesis, it was examined the effects of visible (635 and 655 nm) and near-infrared (810 and 830 nm) light on ATP in solution. It was also examined the biochemical behavior of light-exposed ATP in the luciferine-luciferase and in the hexokinase reactions. In both cases, when irradiated ATP was added the reactions occurred faster and the kinetic parameters were altered. Changes in both reactions were wavelength and dose dependant. When ATP was excited with UV photons, it fluoresced. This fluorescence decreased when Mg2+ was added, probably because the ion binds the phosphates, which are the part of the molecule responsible for light emission. Irradiating the ATP-Mg2+ solution with 655 nm and 830 nm light increased the fluorescence resulting from a displacement of charges in the phosphor-oxygen bond that repels Mg2+. The refraction of light in an ATP solution was observed by the Michelson interferometer and by directly measuring the refractive index. The refractive index changed after red and near-infrared light interaction due to a change in the electrical permittivity of the medium. The same effect was obtained when the solution was exposed to an electrical field, so both light and electrical interaction may share the same mechanism. Since ATP in water is transparent to visible and near-infrared light, and is therefore not a chromophore for those wavelengths, the conclusion is that the observed light interaction with ATP is due to the electromagnetic disturbance produced by the light, which leads to a polarization of the dielectric molecule that is ATP. This interaction of visible and near-infrared electromagnetic energy with ATP offers new perspectives for explaining light interaction at subcellular level.

Author: TORÍO GÓMEZ PABLO.
Year: 2004.
University: VIGO [www.uvigo.es].
Place of defense: ETS INGENIEROS DE TELECOMUNICACIONE.
Place of preparation: ETS INGENIEROS DE TELECOMUNICACIÓN.

Summary: The topic for this Doctoral thesis focuses on the impulsive noise. Both in its characterization, as in the development of methods that puedean minimize its impact on communications in general, and more specifically, on receipt of the digital terrestrial television signal, DVB-T (Digital Video Broadcasting- Terrestrial), based in OFDM (Orthogonal Frequency Division Multiplexing). Bearing in mind that the terrestrial TV signal is transmitted with linear polarization, is studied with particular attention is how impulsive noise that appears simultaneously on the polarization horinzontal and vertical, and how is the impulsive noise appearing simultaneously and vertical polarization and how this fact can be used to reduce its harmful effects. This study has been developed in the following main stages. A) Construction of a measurement system noise impulsive, with the possibility of being able to record two channels simultaneously, which will be used to record polirizaciones horizontal and vertical at the same time. B) Campaign measures, the study of data and presentation of results. C) Development of a method for detection of impulsive noise, with implementation to improve tracking systems are in sync signal reception DVB-T. E) Development of a method for removing impulsive noise, for receiving signals DVB-T, based on the correlation of the horizontal and vertical polarization observed in the campaign for action. The Doctoral thesis presents a study of impulsive noise in radio channels, based on the statement of the results of an extensive campaign of measures and their possterior theoretical analysis. The main contributions to the state of art are particularly apparent three: 1. The observation that the extent of impulsive noise follows a log-normal distribution statistics around. 2. The demonstration of the existence of correlation between the horizontal and vertical polarization of impulsive noise. 3. The creation of new methods to detect and suppress impulsive noise, with specific application to the European standard for digital terrestrial television DVB-T.