2,318 research outputs found

    Continuous production of glycerol by catalytic high pressure hydrogenolysis of sucrose

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    Several continuous reactor systems have been discussed for the catalytic high pressure hydrogenolysis of sucrose to glycerol. Theoretically and actually, continuous reactors lead to lower glycerol yields than in a batch process. Two continuous stirred tank reactors in cascade constitute a reasonable compromise. An economic evaluation of the sucrose route to glycerol in comparison with other synthetic glycerol processes based on allyl chloride and acrolein suggests that the sucrose process can be competitive if a sales potential is developed for the by-products propane-l,2-diol, ethylene glycol, and a mixture of higher polyhydric alcohols containing tetritol, pentitol, methyl fructoside, and hexitol

    Nd-complex-doped polymer channel waveguide laser

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    Laser operation at 1060 nm with slope efficiency of 0.95% and 440 ÎĽW output power for 2% outcoupling was demonstrated in Nd-complex-doped FDA/epoxy channel waveguides, in what to our knowledge is the first report of a rare-earth-ion-doped polymer waveguide laser. The threshold was 45 mW of absorbed pump power

    Epidemiology of dark leaf spot caused by Alternaria brassicicola in organic seed production of cauliflower

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    Dark leaf spot caused by Alternaria brassicicola is a seed-borne disease of Brassicae. Production of healthy seed is essential for the organic vegetable production. Literature on the epidemiology of the disease in organic seed production of Brassica was reviewed and an epidemiological field experiments was carried out. External and internal contamination of seeds with A. brassicicola increased steadily during their development. Colonisation of pod tissues as quantified by TaqMan-PCR increased exponentially. The developed knowledge can be used for optimizing cropping systems for organic seed production with lower risks for seed contamination by Alternaria spp. and to develop critical control points for disease management

    Continuous-wave Lasers in Polymer waveguides

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    Channel waveguides based on a polymer, 6-fluorinated-dianhydride/epoxy, which is actively doped with a rare-earth-ion-doped complex, Nd(thenoyltrifluoroacetone)3 1,10-phenanthroline, have been fabricated. Photoluminescence peaks at 880 nm, 1060 nm, and 1330 nm have been experimentally observed. By optimization of the fabrication\ud procedure of both, host material and optical structure, continuous-wave laser operation on both, the four-level and quasi-three-level transitions near 1060 nm and 880 nm, respectively, has been demonstrated in channel waveguides

    Ultrafast all-optical wavelength conversion in silicon waveguides using femtosecond pump-probe pulses

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    Experimental results on ultrafast all-optical wavelength conversion in silicon-on-insulator waveguides are presented. Red and blue shifts of 10nm have been observed in femtosecond pump-probe experiments. Alloptical switching and the importance of waveguide dispersion are discussed

    Anomalous response of superconducting titanium nitride resonators to terahertz radiation

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    We present an experimental study of KIDs fabricated of atomic layer deposited TiN films, and characterized at radiation frequencies of 350350~GHz. The responsivity to radiation is measured and found to increase with increasing radiation powers, opposite to what is expected from theory and observed for hybrid niobium titanium nitride / aluminium (NbTiN/Al) and all-aluminium (all-Al) KIDs. The noise is found to be independent of the level of the radiation power. The noise equivalent power (NEP) improves with higher radiation powers, also opposite to what is observed and well understood for hybrid NbTiN/Al and all-Al KIDs. We suggest that an inhomogeneous state of these disordered superconductors should be used to explain these observations

    Uniform non-stoichiometric titanium nitride thin films for improved kinetic inductance detector array

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    We describe the fabrication of homogeneous sub-stoichiometric titanium nitride films for microwave kinetic inductance detector (mKID) arrays. Using a 6 inch sputtering target and a homogeneous nitrogen inlet, the variation of the critical temperature over a 2 inch wafer was reduced to <25 %. Measurements of a 132-pixel mKID array from these films reveal a sensitivity of 16 kHz/pW in the 100 GHz band, comparable to the best aluminium mKIDs. We measured a noise equivalent power of NEP = 3.6e-15 W/Hz^(1/2). Finally, we describe possible routes to further improve the performance of these TiN mKID arrays.Comment: 7 pages, 4 figures, submitted to Journal of low temperature physics, Proceedings of LTD-1

    Continuous-wave lasing in a solid polymer

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    Channel waveguides with a Nd-complex-doped fluorinated polymer guiding core were fabricated. For the first time, continuous-wave lasing was demonstrated in a solid polymer. Lasers near 1060 nm and 878 nm were operated for 2 hours
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