1,391 research outputs found

    Development of low temperature dielectric coatings for electrical conductors thirteenth quarterly report

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    Dielectric loss and connector problems at cryogenic temperatur

    Study made of dielectric properties of promising materials for cryogenic capacitors

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    Experimental investigations were conducted to determine dielectric properties of promising materials for cryogenic capacitors to be used in energy storage and pulse applications. The three classes of materials investigated were inorganic bonded ferroelectric materials, anodic coatings on metal foils, and polar low temperature liquids

    Evaluation of thin wall spacecraft electrical wiring. Volume I - Test methods and facilities Technical report no. 1

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    Test methods and facilities used in evaluating performance characteristics of thin wall spacecraft electric wiring under simulated spacecraft environment

    Cryogenic capacitor investigation Final report

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    Electrical and mechanical properties data on dielectrics to estimate parameters of cryogenic capacitor

    Evaluation of thin wall spacecraft electrical wiring. Volume II - Test results and facilities Technical report no. 1

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    Insulation resistance of spacecraft wiring against abrasion, radiation effects, oxygen environment, and extrusion lubricant

    Evaluation of thin wall spacecraft electrical wiring. Volume II - Summary and conclusions Final report

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    Performance characteristics environmentally determined for spacecraft, thin wall wiring - summary and conclusion

    Evaluation of thin wall spacecraft electrical wiring. Volume I - Test results Final report

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    Performance characteristics environmentally determined for spacecraft, thin wall wirin

    Test beam Characterizations of 3D Silicon Pixel detectors

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    3D silicon detectors are characterized by cylindrical electrodes perpendicular to the surface and penetrating into the bulk material in contrast to standard Si detectors with planar electrodes on its top and bottom. This geometry renders them particularly interesting to be used in environments where standard silicon detectors have limitations, such as for example the radiation environment expected in an LHC upgrade. For the first time, several 3D sensors were assembled as hybrid pixel detectors using the ATLAS-pixel front-end chip and readout electronics. Devices with different electrode configurations have been characterized in a 100 GeV pion beam at the CERN SPS. Here we report results on unirradiated devices with three 3D electrodes per 50 x 400 um2 pixel area. Full charge collection is obtained already with comparatively low bias voltages around 10 V. Spatial resolution with binary readout is obtained as expected from the cell dimensions. Efficiencies of 95.9% +- 0.1 % for tracks parallel to the electrodes and of 99.9% +- 0.1 % at 15 degrees are measured. The homogeneity of the efficiency over the pixel area and charge sharing are characterized.Comment: 5 pages, 7 figure

    The development and evaluation of an online application to assist in the extraction of data from graphs for use in systematic reviews

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    These are the data we generated in our evaluation of the graphical user interface. Please see our publication on Wellcome Open Research for information about the evaluations.These are the data we generated in our evaluation of the graphical user interface. Please see our publication on Wellcome Open Research for information about the evaluations

    BLUF Domain Function Does Not Require a Metastable Radical Intermediate State

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    BLUF (blue light using flavin) domain proteins are an important family of blue light-sensing proteins which control a wide variety of functions in cells. The primary light-activated step in the BLUF domain is not yet established. A number of experimental and theoretical studies points to a role for photoinduced electron transfer (PET) between a highly conserved tyrosine and the flavin chromophore to form a radical intermediate state. Here we investigate the role of PET in three different BLUF proteins, using ultrafast broadband transient infrared spectroscopy. We characterize and identify infrared active marker modes for excited and ground state species and use them to record photochemical dynamics in the proteins. We also generate mutants which unambiguously show PET and, through isotope labeling of the protein and the chromophore, are able to assign modes characteristic of both flavin and protein radical states. We find that these radical intermediates are not observed in two of the three BLUF domains studied, casting doubt on the importance of the formation of a population of radical intermediates in the BLUF photocycle. Further, unnatural amino acid mutagenesis is used to replace the conserved tyrosine with fluorotyrosines, thus modifying the driving force for the proposed electron transfer reaction; the rate changes observed are also not consistent with a PET mechanism. Thus, while intermediates of PET reactions can be observed in BLUF proteins they are not correlated with photoactivity, suggesting that radical intermediates are not central to their operation. Alternative nonradical pathways including a keto–enol tautomerization induced by electronic excitation of the flavin ring are considered
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