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581.
Yannick Ledemi Danilo Manzani Sidney J.L. Ribeiro Younes Messaddeq 《Optical Materials》2011,33(12):1916-1920
Multicolor and white light emissions have been achieved in Yb3+, Tm3+ and Ho3+ triply doped heavy metal oxide glasses upon laser excitation at 980 nm. The red (660 nm), green (547 nm) and blue (478 nm) up conversion emissions of the rare earth (RE) ions triply doped TeO2–GeO2–Bi2O3–K2O glass (TGBK) have been investigated as a function of the RE concentration and excitation power of the 980 nm laser diode. The most appropriate combination of RE in the TGBK glass host (1.6 wt% Yb2O3, 0.6 wt% Tm2O3 and 0.1 wt% Ho2O3) has been determined with the purpose to tune the primary colors (RGB) respective emissions and generate white light emission by varying the pump power. The involved infrared to visible up conversion mechanisms mainly consist in a three-photon blue up conversion of Tm3+ ions and a two-photon green and red up conversions of Ho3+ ions. The resulting multicolor emissions have been described according to the CIE-1931 standards. 相似文献
582.
Sandra F. H. Correia Patrícia P. Lima Edison Pecoraro Sidney J. L. Ribeiro Paulo S. Andr Rute A. S. Ferreira Luís D. Carlos 《Progress in Photovoltaics: Research and Applications》2016,24(9):1178-1193
Luminescent solar concentrators (LSCs) are cost‐effective components easily integrated in photovoltaics (PV) that can enhance solar cells' performance and promote the integration of PV architectural elements into buildings, with unprecedented possibilities for energy harvesting in façade design, urban furnishings and wearable fabrics. The devices' performance is dominated by the concentration factor (F), which is higher in cylindrical LSCs compared with planar ones (with equivalent collection area and volume). The feasibility of fabricating long‐length LSCs has been essentially limited up to ten of centimetres with F < 1. We use a drawing optical fibre facility to easily scale up large‐area LSCs (length up to 2.5 m) based on bulk and hollow‐core plastic optical fibres (POFs). The active layers used to coat the bulk fibres or fill the hollow‐core ones are Rhodamine 6G‐ or Eu3+‐doped organic–inorganic hybrids. For bulk‐coated LSCs, light propagation occurs essentially at the POFs, whereas for hollow‐core device light is also guided within the hybrid. The lower POFs' attenuation (~0.1 m−1) enables light propagation in the total fibre length (2.5 m) for bulk‐coated LSCs with maximum optical conversion efficiency (ηopt) and F of 0.6% and 6.5, respectively. For hollow‐core LSCs, light propagation is confined to shorter distances (6–9 × 10−2 m) because of the hybrids' attenuation (1–15 m−1). The hollow‐core optimised device displays ηopt = 72.4% and F = 12.3. The F values are larger than the best ones reported in the literature for large‐area LSCs (F = 4.4), illustrating the potential of this approach for the development of lightweight flexible high‐performance waveguiding PV. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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We review some of the factors which should be considered in the electrical design of in-plant generation systems for industrial facilities. The subjects covered are electrical system arrangements, generator neutral grounding, protective relaying, and load control. 相似文献
585.
An improved mercury balance volumeter is described, which uses a commercially available balance for the determination of the volume of small test pieces. The volume is determined indirectly by using the sample weight and the force necessary to submerge the sample in a mercury reservoir. The accuracy, manipulation, and advantages of the method are discussed. 相似文献
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