Water in oil microemulsions : transient electric birefringence response

The structure of water in oil microemulsions has been investigated using transient electric birefringence. At low water concentrations, transient coalescence of droplets is observed. At higher water concentrations, the Kerr signal probes density fluctuations. A fast negative response is attributed to the relaxation of interfacial layers. Further work is under way to make these preliminary results more quantitative.Nous avons étudié la structure de microémulsions eau dans huile au moyen de la biréfringence électrique transitoire. A faible concentration, on observe l'association des gouttelettes, à concentration moyenne des fluctuations de densité dans le système. Une composante négative, rapide, est attribuée aux fluctuations des interfaces. Une étude plus complète suivra ces résultats préliminaires

Near infrared up-conversion in organic photovoltaic devices using an efficient Yb3+:Ho3+ Co-doped Ln2BaZnO5 (Ln = Y, Gd) phosphor

The first detailed study that combines the use of a new generation of high-efficiency Yb3+:Ho3+ co-doped Y2BaZnO5 near-infrared up-converting phosphors with organic photovoltaic devices is reported. We show that it is possible to obtain a Jsc of 16 µA / cm2 under 986 nm illumination (~390 mW / cm2 corresponding to ~37 suns) leading to an up-conversion external quantum efficiency (UC EQE) of 0.0052%. Through modification of the organic photovoltaic devices to incorporate transparent electrodes we show that UC EQE could be increased to 0.031 %, matching that achieved in amorphous-Si:H PV cells. Accounting for the full spectral range that may be absorbed by the phosphor(~870–1030 nm) yields an up-conversion power conversion efficiency (UC PCE) of 0.073% which again could be improved to 0.45% using transparent electrodes. This technique for utilizing the near-infrared spectral region may therefore offer a potential route to improving the performance of organic photovoltaic devices as research into discovering high-efficiency up-converting phosphors continues to provide improved materials

Sequential Proximal Optimizing Technique in Provisional Bifurcation Stenting With Everolimus-Eluting Bioresorbable Vascular Scaffold: Fractal Coronary Bifurcation Bench for Comparative Test Between Absorb and XIENCE Xpedition.

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