45,040 research outputs found

    A Taxonomic and Ecological Study of the Asilidae of Michigan

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    Seventy-two species of Asilidae have been recorded from Michigan. An additional seven which may occur are included. Keys to subfamilies, genera and species are given. Two subfamilies and twenty-five genera are represented. A discussion of specific identification, habitat, and distribution is given where possible. The Laphria canis complex, index complex, and aeatus complex are discussed. One new species, Laphria calvescenta is described. Laphria disparella has been raised from synonymy. Machimus virginicus was removed from Asilus sensu-latu and placed in the genus Machimus

    Exciton-polaron complexes in pulsed electrically-detected magnetic resonance

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    Several microscopic pathways have been proposed to explain the large magnetic effects observed in organic semiconductors, but identifying and characterising which microscopic process actually influences the overall magnetic field response is challenging. Pulsed electrically-detected magnetic resonance provides an ideal platform for this task as it intrinsically monitors the charge carriers of interest and provides dynamical information which is inaccessible through conventional magnetoconductance measurements. Here we develop a general time domain theory to describe the spin-dependent reaction of exciton-charge complexes following the coherent manipulation of paramagnetic centers through electron spin resonance. A general Hamiltonian is treated, and it is shown that the transition frequencies and resonance positions of the exciton-polaron complex can be used to estimate inter-species coupling. This work also provides a general formalism for analysing multi-pulse experiments which can be used to extract relaxation and transport rates

    Design of an inert fluid injection system, phase 3 Final report

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    Research, development, and design of velocity trim system for third stage of Delta launch vehicl

    Stability of shear flow with density gradient and viscosity

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    Stability of shear flow with density gradient and viscosit

    The Texas Heritage Museum at Hill College, Hillsboro, Texas

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    Using coherent dynamics to quantify spin-coupling within triplet-exciton/polaron complexes in organic diodes

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    Quantifying the spin-spin interactions which influence electronic transitions in organic semiconductors is crucial for understanding their magneto-optoelectronic properties. By combining a theoretical model for three spin interactions in the coherent regime with pulsed electrically detected magnetic resonance experiments on MEH-PPV diodes, we quantify the spin-coupling within complexes comprising three spin-half particles. We determine that these particles form triplet-exciton:polaron pairs, where the polaron:exciton exchange is over 5 orders of magnitude weaker (less than 170 MHz) than that within the exciton. This approach providing a direct spectroscopic approach for distinguishing between coupling regimens, such as strongly bound trions, which have been proposed to occur in organic devices.Comment: 5 pages, 4 figure

    Aircraft and satellite measurement of ocean wave directional spectra using scanning-beam microwave radars

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    A microwave radar technique for remotely measuring the vector wave number spectrum of the ocean surface is described. The technique, which employs short-pulse, noncoherent radars in a conical scan mode near vertical incidence, is shown to be suitable for both aircraft and satellite application, the technique was validated at 10 km aircraft altitude, where we have found excellent agreement between buoy and radar-inferred absolute wave height spectra

    MULTIPAC, a multiple pool processor and computer for a spacecraft central data system, phase 2 Final report

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    MULTIPAC, multiple pool processor and computer for deep space probe central data syste
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