Calculation of the emission power distribution of microstructured OLEDs using the reciprocity theorem

S. Zhang, E.R. Martins, G.A. Turnbull and I.D.W. Samuel are grateful to the Scottish Universities Physics Alliance (SUPA) and the Engineering and Physical Sciences Research Council (EPSRC) for financial support.Integrating photonic microstructures into organic light-emitting diodes (OLEDs) has been a widely used strategy to improve their light out-coupling efficiency. However, there is still a need for optical modelling methods which quantitatively characterise the spatial emission pattern of microstructured OLEDs. In this paper, we demonstrate such rigorous calculation using the reciprocity theorem. The calculation of the emission intensity at each direction in the far field can be simplified into only two simple calculations of an incident plane wave propagating from the far field into a single cell of the periodic structure. The emission from microstructured OLED devices with three different grating periods was calculated as a test of the approach, and the calculated results were in good agreement with experiment. This optical modelling method is a useful calculation tool to investigate and control the spatial emission pattern of microstructured OLEDs.PostprintPeer reviewe

AVALIAÇÃO NUTRITIVA DE FENOS DA PASTAGEM NATURAL DO PARANÁ

Fenos de pastagem natural do Paraná colhidos durante o verão nos municípios de Ponta Grossa, Guarapuava e Tibagi, foram avaliados pela composição química, determinação dos coeficientes de digestibilidade e consumo voluntário com ovinos. Baseados na composição química, os valores encontrados foram semelhantes para os três fenos estudados. No entanto, o feno de Guarapuava apresentou valores mais elevados em FDN e lignina. Entre os coeficientes de digestibilidade, somente o da proteína bruta e do FDN não apresentaram diferença significativa entre os locais (P>0,05). Para a digestibilidade da matéria seca e energia bruta, o feno de Ponta Grossa mostrou-se superior ao de Tibagi. No consumo de matéria seca, proteína e energia digestíveis, não houve diferença significativa (P>0,05) entre locais, mas em relação a energia líquida de manutenção o feno de Ponta Grossa diferiu significativamente do feno de Tibagi (P0.05). As far as digestibility of the dry matter and gross energy are concerned, the hay of Ponta Grossa showed superior qualities when compared with the Tibagi one. No significant differences (P>0.05) were found between all the hays studied. However, in regard to liquid maintenance energy, the Ponta Grossa hay differed significantly from the Tibagi hay (

Quasi-stationary distributions for the Domany-Kinzel stochastic cellular automaton

We construct the {\it quasi-stationary} (QS) probability distribution for the Domany-Kinzel stochastic cellular automaton (DKCA), a discrete-time Markov process with an absorbing state. QS distributions are derived at both the one- and two-site levels. We characterize the distribuitions by their mean, and various moment ratios, and analyze the lifetime of the QS state, and the relaxation time to attain this state. Of particular interest are the scaling properties of the QS state along the critical line separating the active and absorbing phases. These exhibit a high degree of similarity to the contact process and the Malthus-Verhulst process (the closest continuous-time analogs of the DKCA), which extends to the scaling form of the QS distribution.Comment: 15 pages, 9 figures, submited to PR

Gravitational Collapse of Phantom Fluid in (2+1)-Dimensions

This investigation is devoted to the solutions of Einstein's field equations for a circularly symmetric anisotropic fluid, with kinematic self-similarity of the first kind, in $(2+1)$-dimensional spacetimes. In the case where the radial pressure vanishes, we show that there exists a solution of the equations that represents the gravitational collapse of an anisotropic fluid, and this collapse will eventually form a black hole, even when it is constituted by the phantom energy.Comment: 10 page

Manifestações Abdominais Do Linfoma Extranodal: Ensaio Iconográfico

In the appropriate clinical setting, certain aspects of extranodal abdominal lymphoma, as revealed by current cross-sectional imaging techniques, should be considered potentially diagnostic and can hasten the diagnosis. In addition, diagnostic imaging in the context of biopsy-proven lymphoma can accurately stage the disease for its appropriate treatment. The purpose of this article was to illustrate the various imaging aspects of extranodal lymphoma in the abdomen. © Colégio Brasileiro de Radiologia e Diagnóstico por Imagem.49639740

Modelling J/psi production and absorption in a microscopic nonequilibrium approach

Charmonium production and absorption in heavy ion collisions is studied with the Ultrarelativisitic Quantum Molecular Dynamics model. We compare the scenario of universal and time independent color-octet dissociation cross sections with one of distinct color-singlet J/psi, psi' and chi_c states, evolving from small, color transparent configurations to their asymptotic sizes. The measured J/psi production cross sections in pA and AB collisions at SPS energies are consistent with both - purely hadronic - scenarios. The predicted rapidity dependence of J/psi suppression can be used to discriminate between the two experimentally. The importance of interactions with secondary hadrons and the applicability of thermal reaction kinetics to J/psi absorption are investigated. We discuss the effect of nuclear stopping and the role of leading hadrons. The dependence of the psi' to J/psi ratio on the model assumptions and the possible influence of refeeding processes is also studied.Comment: 35 pages, 16 figure

Erratum: "Rotation, spectral variability, magnetic geometry and magnetosphere of the Of?p star CPD -28° 2561"

Este documento es una errata de "Rotation, spectral variability, magnetic geometry and magnetosphere of the Of?p star CPD -28° 2561" (ver documento relacionado).Instituto de Astrofísica de La Plat

BAs and boride III-V alloys

Boron arsenide, the typically-ignored member of the III-V arsenide series BAs-AlAs-GaAs-InAs is found to resemble silicon electronically: its Gamma conduction band minimum is p-like (Gamma_15), not s-like (Gamma_1c), it has an X_1c-like indirect band gap, and its bond charge is distributed almost equally on the two atoms in the unit cell, exhibiting nearly perfect covalency. The reasons for these are tracked down to the anomalously low atomic p orbital energy in the boron and to the unusually strong s-s repulsion in BAs relative to most other III-V compounds. We find unexpected valence band offsets of BAs with respect to GaAs and AlAs. The valence band maximum (VBM) of BAs is significantly higher than that of AlAs, despite the much smaller bond length of BAs, and the VBM of GaAs is only slightly higher than in BAs. These effects result from the unusually strong mixing of the cation and anion states at the VBM. For the BAs-GaAs alloys, we find (i) a relatively small (~3.5 eV) and composition-independent band gap bowing. This means that while addition of small amounts of nitrogen to GaAs lowers the gap, addition of small amounts of boron to GaAs raises the gap (ii) boron ``semi-localized'' states in the conduction band (similar to those in GaN-GaAs alloys), and (iii) bulk mixing enthalpies which are smaller than in GaN-GaAs alloys. The unique features of boride III-V alloys offer new opportunities in band gap engineering.Comment: 18 pages, 14 figures, 6 tables, 61 references. Accepted for publication in Phys. Rev. B. Scheduled to appear Oct. 15 200