Stepwise Filtering of the Internal Layers of Dendrimers by Transverse-Relaxation-Edited NMR

The characteristic distribution of transverse relaxation times (T2) within dendrimers (shorter values at the core than the periphery) can be exploited in T2-edited 1D and 2D NMR experiments for the stepwise filtering of internal nuclei according to their topology within the dendritic structure. The resulting filtered spectra, which can be conceived as corresponding to virtual hollow dendrimers, benefit from reduced signal overlap, thus facilitating signal assignment and characterization. The generality of the method as a powerful tool in structural and end-group analysis has been confirmed with various dendritic families and nuclei (1H, 13C, 31P)This work was financially supported by the Spanish Government (CTQ2009-10963, CTQ2012-34790, CTQ2009-14146-C02-02, CTQ2012-33436) and the Xunta de Galicia (10CSA209021PR and CN2011/037). L.F.P. thanks the Portuguese Foundation for Science and Technology (FCT MCTES) for a Ph.D. grant (SFRH/BD/37341/2007)S

A theoretical analysis of the impact of atmospheric parameters on the spectral, electrical and thermal performance of a concentrating III–V triple-junction solar cell

The spectral sensitivity of a concentrating triple junction (3J) solar cell has been investigated. The atmospheric parameters such as the air mass (AM), aerosol optical depth (AOD) and precipitable water (PW) change the distribution of the solar spectrum in a way that the spectral, electrical and thermal performance of a 3J solar cell is affected. In this paper, the influence of the spectral changes on the performance of each subcell and whole cell has been analysed. It has been shown that increasing the AM and AOD have a negative impact on the spectral and electrical performance of 3J solar cells while increasing the PW has a positive effect, although, to a lesser degree. A three-dimensional finite element analysis model is used to quantify the effect of each atmospheric parameter on the thermal performance for a range of heat transfer coefficients from the back-plate to the ambient air and also ambient temperature. It is shown that a heat transfer coefficient greater than 1300 W/(m(2) K) is required to keep the solar cell under 100 degrees C at all times. In order to get a more realistic assessment and also to investigate the effect of heat transfer coefficient on the annual energy yield, the methodology is applied for four US locations using data from a typical meteorological year (TMY3)

Kuvausryhmän hierarkia

En este trabajo se estudian procedimientos para la elección entre las soluciones eficientes del Problema de Programación Lineal con Objetivos Múltiples, cuando el decisor manifiesta preferencias sobre ciertas ordenaciones de las valoraciones de las funciones objetivo, utilizándose como criterio de valoración global funciones basadas en el k-ésimo valor del vector de los objetivos ordenado en cada punto. Se desarrollan procedimientos para generar ordenaciones compatibles con la información del decisor. Estos se incorporan en un proceso interactivo que proporciona una solución eficiente final con un mayor compromiso, a juicio del decisor, en las valoraciones de todos los objetivos