1,460 research outputs found

    Perspectives on organic light-emitting diodes for display applications

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    Herein, we describe a number of key issues that concern the commercialization of organic light-emitting diodes for display applications. We will firstly outline the historical and market contexts that show the potential for organic electronics as a viable display technology. Next, we will discuss the chemical structures for a range of both small-molecular and polymer organic semiconducting compounds, and how the electronic properties are governed thereof. Also we will briefly discuss various common film deposition and device fabrication strategies. Then, we will describe two factors that are highly relevant for commercially viable organic light-emitting diodes, namely charge balance, and device degradation. Finally, we will outline some methods for achieving the high-volume throughput of organic electronics via well-established technologies that are used in the printing industr

    K-Ar age determinations of some Miocene-Pliocene basalts in Israel: their significance to the tectonics of the Rift Valley

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    Thirty samples of Upper Tertiary basalts intruding marine and continental sequences were by the K-Ar method. Four volcanic phases are recorded: (a) 24.8±1.5 Ma of the Raqabat e Na'ame dike in Central Sinai; (b) 20.4±0.7 Ma of basalt intrusions in Central Sinai and the Arava. Some of these are offset by E-W to NE-SW dextral faults of the Central Sinai - Negev Shear Zone; (c) 14.5±0.3 to 4.9±1.3 Ma of basalt flows in the Eastern Galilee and the Coastal Plain; (d) 2.7±0.6 Ma of ‘En Yahav dike. These results contribute to the correlation between Tertiary continental formations from different areas, and put limits on the age of tectonic events, such as folding in the Syrian arc, faulting in the Central Sinai - Negev Shear Zone and shearing along the Jordan Rif

    Canonical Expansion of PT-Symmetric Operators and Perturbation Theory

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    Let HH be any \PT symmetric Schr\"odinger operator of the type 2Δ+(x12+...+xd2)+igW(x1,...,xd) -\hbar^2\Delta+(x_1^2+...+x_d^2)+igW(x_1,...,x_d) on L2(Rd)L^2(\R^d), where WW is any odd homogeneous polynomial and gRg\in\R. It is proved that H\P H is self-adjoint and that its eigenvalues coincide (up to a sign) with the singular values of HH, i.e. the eigenvalues of HH\sqrt{H^\ast H}. Moreover we explicitly construct the canonical expansion of HH and determine the singular values μj\mu_j of HH through the Borel summability of their divergent perturbation theory. The singular values yield estimates of the location of the eigenvalues \l_j of HH by Weyl's inequalities.Comment: 20 page

    Zircon dissolution in a ductile shear zone, Monte Rosa granite gneiss, northern Italy

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    The sizes, distributions and shapes of zircon grains within variably deformed granite gneiss from the western Alps have been studied. Zircon shows numerous indicators of a metamorphic response in both the host gneiss and a 5 cm wide continuous ductile shear zone, within which the zircon grain sizes range from <1 µm to >50 µm. However, the very fine grain sizes are virtually absent from grain boundaries. Within this zone, zircons consistently have more rounded and embayed margins, which are interpreted as evidence of dissolution in response to fluid influx during shearing. Zircons are preferentially located near metamorphic muscovite in both the host gneiss and the shear zone and tend to show the poorest crystal shape, indicating that fluids linked to the formation and presence of muscovite may enhance both the crystallization of zircon and its subsequent dissolution. Larger zircon crystals typically show a brittle response to deformation when adjacent to phyllosilicates, with fractures consistently perpendicular to the (001) mica cleavage. The variety of metamorphic behaviour observed for zircon indicates that it may be highly reactive in sub-solidus mid-crustal metamorphic environments

    Amaranthus asplundii Thell. var. australis Hunz.

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    Quebrada del Churqui, camino La Viña-AmblayopublishedVersio

    Assessing the potential of social media for estimating recreational use of urban and peri-urban forests

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    Acknowledgements The research for this paper was financially supported through the Swiss Federal Office for the Environment (FOEN). The views and opinions expressed in this paper are those of the authors, and do not necessarily represent the policies or official positions of the FOEN or the institutions they work for. We thank Rahul Deb Das for his assistance in data collection and processing. We gratefully acknowledge the comments and feedback of two anonymous reviewers.Peer reviewedPublisher PD

    Dioscorea haumanii Xifreda

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    Urundel, arroyo NipanpublishedVersio

    Amaranthus asplundii Thell. var. australis Hunz.

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    Quebrada del Churqui, camino La Viña-AmblayopublishedVersio

    Amaranthus kloosianus Hunz.

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    La Ramadita (a ± 25 km de la ciudad de La Rioja)publishedVersio
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