Influence of Nb-doping on the structural and electrical properties of lanthanum molybdates, La5.4MoO11.1

Nowadays, hydrogen is receiving a great deal of attention as an energy carrier. Commonly, it is obtained by hydrocarbons reforming, such as natural gas, coal and biomass. However, the resulting hydrogen needs to be purified to remove by-products and impurities, increasing the production costs. An alternative for hydrogen production is proton-conducting ceramics, where hydrogen separation takes place via a chemical potential gradient across the membrane.1, 2 In this work, Nb-doped La6MoO12--based compounds have been investigated as part of a new family of materials very competitive as SOFC electrolyte and hydrogen separation membranes.3 These materials, La5.4Mo1-xNbxO11.1-x/2 (x = 0.05, 0.10, 0.15 y 0.20) were synthesized by the freeze-drying precursor method and calcination conditions have been optimized to obtain single phases. A complete characterization has been carried out using X-Ray powder diffraction and scanning and transmission electron microscopy. The total conductivity was determined by complex impedance spectroscopy at different atmospheres. Different polymorphs are obtained as a function of the cooling rate and the dopant amount. The samples cooled by quenching are cubic with a fluorite-type structure (Fm3 ̅m) and the ones cooled at 50 y 0.5 ºC•min-1 are rhombohedral (R1 and R2 polymorphs). For niobium contents higher than x = 0.10 the R1 polymorph is stabilised at cooling rates equal or inferior to 50 ºC•min-1. For all three series, the incorporation of niobium into La5.4MoO11.1 increases the conductivity, reaching the best values for x=0.10 and the sample obtained by quenching.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Tunable ring resonator filter for OFDM Transmission systems

A novel tunable filter is theoretically demonstrated. It is based on a ring resonator with an amplifier and a noise filter in the loop. This optoelectronic device has potential as a high-sensitivity receiver and as a tunable demultiplexer in OFDM transmission systems.Publicad

Multimode interference filter to solve degradation on coupler common-mode rejection

After quantifying degradation of a common mode rejection ratio (CMRR) 3dB-coupler due to excitation of TE01 mode, a novel compact circuit including multimode interference (MMI) coupler+bend+MMI+filter (CBF) is proposed. We show a CBF circuit has better CMRR at the expense of moderate loss. A complete tolerance analysis to main geometrical parameters has also been carried out.Publicad

La literatura emblemática, Goya y la avaricia

GOYA, A CABALLO ENTRE DOS EPOCAS, RECURRIO A LA EMBLEMATICA COMO FUENTE DE INSPIRACION EN ALGUNAS DE SUS OBRAS, A LAS QUE IMPRIMIO SU PERSONAL INTERPRETACION. CON ESTA ORIENTACION, ENTRE SUS PRINCIPALES FUENTES SE ENCUENTRAN LOS EMBLEMAS DE ALCIATO Y EL TEATRO MORAL DE VAENIUS. (A.B.C./ L.A.G.

" La familia de Carlos IV" de Goya: una interpretación desde la emblemática

La familia de Carlos IV podría encuadrarse, si tenemos en cuenta a Palomino, como un retrato historiado de asunto metafórico. Este pretendería mostrarla como una monarquía ilustrada que actúa con conocimiento y en base a la razón conforme a las ideas desarrolladas por la literatura regio-política española. Estaríamos así ante un espejo de monarquía ideal creado por la invención de Goya que, desgraciadamente, la terca realidad, se encargó de desmentir.The Family of Charles IV could be classified, according to Palomino, as a "historiado" portrait [which means that for its elaboration it is necessary to keep the same adjustment and restraint as in a story] of metaphorical matter, which would be trying to show the Royal Family as an enlightened monarchy that behaves with knowledge and following the commands of the reason, in accordance to the ideas developed by the Spanish regal political literature. If so, we would be looking at a mirror of ideal monarchy created by Goya's invention, that, unfortunately, the stubborn reality finally denied

Characterization of electrical crosstalk in 4T-APS arrays using TCAD simulations

TCAD simulations have been conducted on a CMOS image sensor in order to characterize the electrical component of the crosstalk between pixels through the study of the electric field distribution. The image sensor consists on a linear array of five pinned photodiodes (PPD) with their transmission gates, floating diffusion and reset transistors. The effect of the variations of the thickness of the epitaxial layer has been addressed as well. In fact, the depth of the boundary of the epitaxial layer affects quantum efficiency (QE) so a correlation with crosstalk has been identified.Ministerio de Economía y Competitividad TEC2015-66878-C3-1RJunta de Andalucía TIC 2012-2338Office of Naval Research (USA) N00014141035

A Generalized Regression Methodology for Bivariate Heteroscedastic Data

We present a methodology for reducing a straight line fitting regression problem to a Least Squares minimization one. This is accomplished through the definition of a measure on the data space that takes into account directional dependences of errors, and the use of polar descriptors for straight lines. This strategy improves the robustness by avoiding singularities and non-describable lines. The methodology is powerful enough to deal with non-normal bivariate heteroscedastic data error models, but can also supersede classical regression methods by making some particular assumptions. An implementation of the methodology for the normal bivariate case is developed and evaluated

Analysis of double-parallel amplified recirculating optical-delay lines

A novel method of analysis of double-parallel amplified recirculating optical-delay lines (DPAROD) is presented. The location of the maxima and the minima of the transfer function for this configuration is calculated and experimentally demonstrated. The influence of different parameters, such as the coupling coefficients, gains, lengths of the fiber loops and fractional losses of the directional couplers, on the shape of the transfer function are analyzed. Different measurements have been taken to verify this model. The potential application of these interconnected delay loops as filters is a reason for developing this method.Publicad

Improved estimation of Weibull Parameters considering unreliability uncertainties

We propose a linear regression method for estimating Weibull parameters from life tests. The method uses stochastic models of the unreliability at each failure instant. As a result, a heteroscedastic regression problem arises that is solved by weighted least squares minimization. The main feature of our method is an innovative s-normalization of the failure data models, to obtain analytic expressions of centers and weights for the regression. The method has been Monte Carlo contrasted with Benard?s approximation, and Maximum Likelihood Estimation; and it has the highest global scores for its robustness, and performance