2,320 research outputs found

    Solid state television camera system Patent

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    Solid state television camera system consisting of monolithic semiconductor mosaic sensor and molecular digital readout system

    Rotating Boson Stars and Q-Balls

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    We consider axially symmetric, rotating boson stars. Their flat space limits represent spinning Q-balls. We discuss their properties and determine their domain of existence. Q-balls and boson stars are stationary solutions and exist only in a limited frequency range. The coupling to gravity gives rise to a spiral-like frequency dependence of the boson stars. We address the flat space limit and the limit of strong gravitational coupling. For comparison we also determine the properties of spherically symmetric Q-balls and boson stars.Comment: 22 pages, 18 figure

    One pot synthesis of a stable and cost effective silver particle free ink for inkjet printed flexible electronics

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    Silver particle free inks display immense superiority and potential over silver nanoparticle based inks in the aspect of synthesis, flexibility and low temperature processing, which has attracted considerable research interest as an alternative for fabricating conductive structures in recent years. Although recent research on silver particle free inks has led to beneficial results, there are still some drawbacks some of the inks are chemically unstable and hence are not suitable for industrial inkjet printing process, although they have good conductivity; while others are cheap in terms of raw material costs but are complicated to make due to the complex synthetic route or using hazardous procedures, or are not compatible with inkjet printing. Therefore, it will be advantageous to develop a stable, cheap and inkjet printable silver particle free ink using a simple synthetic procedure. Alcohols are favorable solvents for silver particle free inks that can provide the ink with essential fluid properties for inkjet printing. However, they have some negative effects on the ink performance due to their physicochemical properties, which should be avoided. In this work, a simple do it yourself silver particle free ink is presented, which shows high chemical stability, low cost and good printability. The ink is formulated via a simple silver oxalate precursor route in alcohols. The fluid property, thermal property, stability and electrical performance of the inks based on different alcohols were investigated and optimized to obtain the final ink for printing on glass and flexible polyimide substrates. The printed Ag features yielded a resistivity of 15.46 amp; 956; amp; 937; cm at a sintering temperature of 180 C, which is equivalent to 10 times bulk silver. Based on a comprehensive assessment, we can offer a low cost, easy to make, reliable and highly competitive ink for flexible printed electronic

    Repairing Socially Aggregated Ontologies Using Axiom Weakening

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    Ontologies represent principled, formalised descriptions of agents’ conceptualisations of a domain. For a community of agents, these descriptions may differ among agents. We propose an aggregative view of the integration of ontologies based on Judgement Aggregation (JA). Agents may vote on statements of the ontologies, and we aim at constructing a collective, integrated ontology, that reflects the individual conceptualisations as much as possible. As several results in JA show, many attractive and widely used aggregation procedures are prone to return inconsistent collective ontologies. We propose to solve the possible inconsistencies in the collective ontology by applying suitable weakenings of axioms that cause inconsistencies

    Averaged Solvent Embedding Potential Parameters for Multiscale Modeling of Molecular Properties

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    Published version available in J. Chem. Theory Comput., 2016, 12 (4), pp 1684–1695. We derive and validate averaged solvent parameters for embedding potentials to be used in polarizable embedding quantum mechanics/molecular mechanics (QM/MM) molecular property calculations of solutes in organic solvents. The parameters are solvent-specific atom-centered partial charges and isotropic polarizabilities averaged over a large number of geometries of solvent molecules. The use of averaged parameters reduces the computational cost to obtain the embedding potential, which can otherwise be a rate-limiting step in calculations involving large environments. The parameters are evaluated by analyzing the quality of the resulting molecular electrostatic potentials with respect to full QM potentials. We show that a combination of geometry-specific parameters for solvent molecules close to the QM region and averaged parameters for solvent molecules further away allows for efficient polarizable embedding multiscale modeling without compromising the accuracy. The results are promising for the de- velopment of general embedding parameters for biomolecules, where the reduction in computational cost can be considerable

    Characterising WIMPs at a future e+ee^+e^- Linear Collider

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    We investigate the prospects for detecting and measuring the parameters of WIMP dark matter in a model independent way at the International Linear Collider. The signal under study is direct WIMP pair production with associated initial state radiation e+eχχγe^+e^- \rightarrow \chi\chi\gamma. The analysis accounts for the beam energy spectrum of the ILC and the dominant machine induced backgrounds. The influence of the detector parameters are incorporated by full simulation and event reconstruction within the framework of the ILD detector concept. We show that by using polarised beams, the detection potential is significantly increased by reduction of the dominant SM background of radiative neutrino production e+eννγe^+e^- \rightarrow \nu\nu\gamma. The dominant sources of systematic uncertainty are the precision of the polarisation measurement and the shape of the beam energy spectrum. With an integrated luminosity of 500 fb the helicity structure of the interaction involved can be inferred, and the masses and cross-sections can be measured with a relative accuracy of the order of 1 %.Comment: 20 pages, 11 figure

    Large and Almost Maximal Neutrino Mixing within the Type II See-Saw Mechanism

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    Within the type II see-saw mechanism the light neutrino mass matrix is given by a sum of a direct (or triplet) mass term and the conventional (type I) see-saw term. Both versions of the see-saw mechanism explain naturally small neutrino masses, but the type II scenario offers interesting additional possibilities to explain large or almost maximal or vanishing mixings which are discussed in this paper. We first introduce ``type II enhancement'' of neutrino mixing, where moderate cancellations between the two terms can lead to large neutrino mixing even if all individual mass matrices and terms generate small mixing. However, nearly maximal or vanishing mixings are not naturally explained in this way, unless there is a certain initial structure (symmetry) which enforces certain elements of the matrices to be identical or related in a special way. We therefore assume that the leading structure of the neutrino mass matrix is the triplet term and corresponds to zero U_{e3} and maximal theta_{23}. Small but necessary corrections are generated by the conventional see-saw term. Then we assume that one of the two terms corresponds to an extreme mixing scenario, such as bimaximal or tri-bimaximal mixing. Deviations from this scheme are introduced by the second term. One can mimic Quark-Lepton Complementarity in this way. Finally, we note that the neutrino mass matrix for tri-bimaximal mixing can be -- depending on the mass hierarchy -- written as a sum of two terms with simple structure. Their origin could be the two terms of type II see-saw.Comment: 25 pages. Comments and references added, to appear in JHE

    Large area inkjet printed metal halide perovskite LEDs enabled by gas flow assisted drying and crystallization

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    We demonstrate the upscaling of inkjet printed metal halide perovskite light emitting diodes. To achieve this, the drying process, critical for controlling the crystallization of the perovskite layer, was optimized with an airblade like slit nozzle in a gas flow assisted vacuum drying step. This yields large, continuous perovskite layers in light emitting diodes with an active area up to 1600 mm
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