187,010 research outputs found
Covariant density functional theory for decay of deformed proton emitters: A self-consistent approach
No full textAbstractProton radioactivity from deformed nuclei is described for the first time by a self-consistent calculation based on covariant relativistic density functionals derived from meson exchange and point coupling models. The calculation provides an important new test to these interactions at the limits of stability, since the mixing of different angular momenta in the single particle wave functions is probed
Eumelanin–PEDOT:PSS Complementing En Route to Mammalian-Pigment-Based Electrodes: Design and Fabrication of an ITO-Free Organic Light-Emitting Device
No full textThe growing interest toward biocompatible and bioinspired materials is boosting the investigation and the engineering of natural products as active components in electronic devices. The human pigment melanin, and particularly its subgroup composed by the eumelanins, the black-brown pigments derived from the oxidative polymerization of L-3,4-dihydroxyiphenylalanine (l-DOPA) via 5,6-dihydroxy-indole intermediates are increasingly emerging as valuable candidates for organic (bio)electronics applications. Capitalizing on a recently developed protocol to prepare high quality eumelanin coatings, this paper reports herein the design and the integration of standard commercial poly(3,4-ethylenedioxythiophene) with the poly(styrenesulfonate) (PEDOT:PSS) with eumelanin pigment. The new blend has made it possible to obtain a water stable quite transparent thin film, able to operate as an electrode for organic devices, complementing the PEDOT:PSS conductivity with the peculiar eumelanin properties, including adhesion, water stability, and ionic–electronic conductivity. As proof of concept, an unprecedented indium tin oxide-free organic light emitting diode implementing an eumelanin–PEDOT layer as the anode is fabricated and characterized. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei
Interlaboratory indoor ageing of roll-to-roll and spin coated organic photovoltaic devices: Testing the ISOS tests
No full textThe inter-comparability of ageing of organic photovoltaic (OPV) technologies in dark is addressed. Four primary factors that affect the reproducibility of the ageing rate determination and inter-comparison are discussed: production/encapsulation of the samples, current-voltage (IV) characterization, testing conditions for ageing and lifetime determination from a decay curve. Results of inter-laboratory ageing studies of roll-to-roll and spin coated samples with correspondingly flexible plastic packaging and glass stored in dark conditions among 7 laboratories are presented. ISOS test conditions, proposed recently as guiding protocols for testing OPV stability, are applied in the study. The reproducibility of the performance versus the production and encapsulation techniques is firstly studied. The results reveal a significant improvement in the reproducibility when going from manual spin coating to roll-to-roll production. Furthermore, the reproducibility of current-voltage (IV) measurement and preconditioning (light soaking treatments) are addressed. Additionally, the inter-comparison of the degradation rates of the samples aged under three different dark test conditions (ambient, dry/heat, damp heat) reported by different groups are analyzed revealing a reasonable agreement. Finally, a logarithmic diagram for OPV lifetime associated with common time units is proposed that allows conveniently categorizing and intercomparing the stability performance of different samples aged under different test conditions. © 2014 Elsevier Ltd. All rights reserved
Proton emission, gamma deformation, and the spin of the isomeric state of Ho-141
No full textAbstractThe nonadiabatic quasiparticle model for triaxial shapes is used to perform calculations for decay of 141Ho, the only known odd-Z even-N deformed nucleus for which fine structure in proton emission from both ground and isomeric states was observed. All experimental data corresponding to this unique case namely, the rotational spectra of parent and daughter nuclei, decay widths and branching ratios for ground and isomeric states, could be well explained with a strong triaxial deformation γ∼20°. The recent experimental observation of fine structure decay from the isomeric state, can be explained only with an assignment of I=3/2+ as the decaying state, in contradiction with the previous assignment, of I=1/2+, based on adiabatic calculations. This study reveals that proton emission measurements could be a precise tool to probe triaxial deformations and other structural properties of exotic nuclei beyond the proton drip-line
Nonadiabatic quasiparticle description of triaxially deformed proton emitters
No full textExact calculations are performed for proton emission from triaxial nuclei by extending the nonadiabatic
quasiparticle method to include the triaxial degree of freedom. We present for the first time a proper formalism
for triaxial proton emitters, which includes the treatment of the pairing residual interaction and the coupling with
the excited states of the daughter nucleus. The results for the nuclei 161Re and 185Bi are discussed. In contrast
to an earlier prediction, where this problem was addressed with approximate methods, a weak dependance on
triaxial deformation, especially in the nonadiabatic case, is found
Accuracy of global geoid height models in local area: Tests on Campania region (Italy)
No full textNowadays GPS technology permits to reach millimeter or sub-millimeter horizontal relative accuracy levels over very long distances (up to hundreds of kilometers). The vertical GPS accuracy is more difficult to obtain. In addition, because GPS heights are referred to ellipsoid, their transformation into orthometric heights requires the use of a geoid model that influences with its accuracy the quality of the results. Usually a local geoid model is characterized by a high level of accuracy, but often it has a fee. Global geoid models are free available and their accuracy is to test in the local area where they are to use so to evaluate their suitability for the user purposes. This paper is aimed to compare different Global Geoid Models testing their accuracy on Campania region (Italy). Particularly, models respectively named EGM84, EGM96 and EGM2008, are considered and tested on 18 points corresponding to GNSS Permanent Stations in Campania. For the best resulting model, the EGM2008, a solution to improve further its performance is adopted
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