1,419 research outputs found

    Dopant for sodium niobate capacitor dielectric

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    Sodium niobate dielectric doped with barium titanate has potential application in integrated circuits with high packing densities and voltage levels below 5 to 8 volts

    AstroGrid-D: Enhancing Astronomic Science with Grid Technology

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    We present AstroGrid-D, a project bringing together astronomers and experts in Grid technology to enhance astronomic science in many aspects. First, by sharing currently dispersed resources, scientists can calculate their models in more detail. Second, by developing new mechanisms to efficiently access and process existing datasets, scientific problems can be investigated that were until now impossible to solve. Third, by adopting Grid technology large instruments such as robotic telescopes and complex scientific workflows from data aquisition to analysis can be managed in an integrated manner. In this paper, we present prominent astronomic use cases, discuss requirements on a Grid middleware and present our approach to extend/augment existing middleware to facilitate the improvements mentioned above

    In situ measurements of ship tracks

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    It has long been known that cloud droplet concentrations are strongly influenced by cloud condensation nuclei (CCN) and that anthropogenic sources of pollution can affect CCN concentrations. More recently it has been suggested that CCN may play an important role in climate through their effect on cloud albedo. A interesting example of the effect of anthropogenic CCN on cloud albedo is the so-called 'ship track' phenomenon. Ship tracks were first observed in satellite imagery when the ship's emissions were evidently needed for the formation of a visible cloud. However, they appear more frequently in satellite imagery as modifications to existing stratus and stratocumulus clouds. The tracks are seen most clearly in satellite imagery by comparing the radiance at 3.7 microns with that at 0.63 and 11 microns. To account for the observed change in radiance, droplet concentrations must be high, and the mean size of the droplets small, in ship tracks. Researchers describe what they believe to be the first in situ measurements in what appears to have been a ship track

    Graph Based Disambiguation of Named Entities using Linked Data

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    Identifying entities such as people, organizations, songs, or places in natural language texts is needful for semantic search, machine translation, and information extraction. A key challenge is the ambiguity of entity names, requiring robust methods to disambiguate names to the entities registered in a knowledge base. Several approaches aim to tackle this problem, they still achieve poor accuracy. We address this drawback by presenting a novel knowledge-base-agnostic approach for named entity disambiguation. Our approach includes the HITS algorithm combined with label expansion strategies and string similarity measure like the n-gram similarity. Based on this combination, we can efficiently detect the correct URIs for a given set of named entities within an input text

    Measurements of the light-absorbing material inside cloud droplets and its effect on cloud albedo

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    Most of the measurements of light-absorbing aerosol particles made previously have been in non-cloudy air and therefore provide no insight into aerosol effects on cloud properties. Here, researchers describe an experiment designed to measure light absorption exclusively due to substances inside cloud droplets, compare the results to related light absorption measurements, and evaluate possible effects on the albedo of clouds. The results of this study validate those of Twomey and Cocks and show that the measured levels of light-absorbing material are negligible for the radiative properties of realistic clouds. For the measured clouds, which appear to have been moderately polluted, the amount of elemental carbon (EC) present was insufficient to affect albedo. Much higher contaminant levels or much larger droplets than those measured would be necessary to significantly alter the radiative properties. The effect of the concentrations of EC actually measured on the albedo of snow, however, would be much more pronounced since, in contrast to clouds, snowpacks are usually optically semi-infinite and have large particle sizes
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