Sökning: "light emitting diodes"

Visar resultat 6 - 10 av 50 uppsatser innehållade orden light emitting diodes.

1. 6. Impact of different light sources on the responses of moth

   Magister-uppsats, Högskolan i Halmstad

   Författare :Yanhe Zhou; [2021]
   Nyckelord :Artificial light at night ALAN ; Greater wax moth; Light Attraction; light emitting diodes; LED; Galleria mellonella;

   Sammanfattning : In recent decades, the negative effects of artificial light at night on natural ecosystems have attracted the attention of ecologists. Studies have shown that artificial light at night leads to a considerable reduction in insects and has a worrying impact on terrestrial ecosystems, including nocturnal insects (e.g. Lepidoptera) such as moths. LÄS MER

3. 7. Short wavelength UV–LED photoinitiated radical polymerization of acrylate–based coating systems—A comparison with conventional UV curing.

   Uppsats för yrkesexamina på avancerad nivå, Uppsala universitet/Strukturkemi

   Författare :Olof Torfgård; [2021]
   Nyckelord :UV; LED; UVC; UVB; UVA; paint; acrylate; curing; Sherwin–Williams; ATR-FTIR; spectroradiometer; photoinitiator; the mercury arc lamp;

   Sammanfattning : The present work was performed at Sherwin–Williams Sweden group AB with the objective of comparing short-wavelength light emitting diodes (UVB/UVC) with the conventional mercury arc lamp as a curing method of acrylate-based, UV-paint undergoing free-radical polymerization when exposed to UV-radiation. Due to environmental and health risks, mercury-doped radiation sources will be phased out in the near future, according to the United Nations Minamata convention, hence new alternatives are needed. LÄS MER

4. 8. Compensating the Changing Reactive Power in the Medium-Voltage Grid in Stockholm

   Master-uppsats, KTH/Skolan för elektroteknik och datavetenskap (EECS)

   Författare :Gabriel Nylander; [2020]
   Nyckelord :;

   Sammanfattning : A decline in inductive reactive power has been noted by several DNOs around Europe for the last decade. Why this is happening is unknown. One of the DNOs is the Swedish DNO Ellevio AB that has seen large decreases in demand of inductive reactive power from their primary substations. LÄS MER

5. 9. Black-box optimization of simulated light extraction efficiency from quantum dots in pyramidal gallium nitride structures

   Master-uppsats, Linköpings universitet/Matematiska institutionen

   Författare :Karl-Johan Olofsson; [2019]
   Nyckelord :Black-box optimization; Radial basis functions; Gallium nitride; light extraction efficiency; FDTD; surrogate functions; semiconductors; global optimization;

   Sammanfattning : Microsized hexagonal gallium nitride pyramids show promise as next generation Light Emitting Diodes (LEDs) due to certain quantum properties within the pyramids. One metric for evaluating the efficiency of a LED device is by studying its Light Extraction Efficiency (LEE). LÄS MER

7. 10. Microscopy techniques for studying polymer-polymer blends

   Uppsats för yrkesexamina på avancerad nivå, Umeå universitet/Institutionen för fysik

   Författare :Sandra Mattsson; [2019]
   Nyckelord :CLEM; correlative light and electron microscopy; correlative microscopy; fluorescence microscopy; scanning electron microscopy; phase contrast microscopy; polymer blend; morphology; super yellow; PEO; poly ethylene oxide ; CLEM; korrelativ ljus- och elektronmikroskopi; korrelativ mikroskopi; fluorescensmikroskopi; svepelektronmikroskopi; faskontrastsmikroskopi; polymerblandning; morfologi; super yellow; PEO; poly etylenoxid ;

   Sammanfattning : Semiconductors are used in many electronic applications, for example diodes, solar cells and transistors. Typically, semiconductors are inorganic materials, such as silicon and gallium arsenide, but lately more research and development has been devoted to organic semiconductors, for example semiconducting polymers. LÄS MER