Sökning: "Laser cleaning"

Visar resultat 6 - 10 av 20 avhandlingar innehållade orden Laser cleaning.

  1. 6. The absorptance of metallic alloys to Nd:YAG and Nd:YLF laser light

    Författare :David Bergström; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Produktionsutveckling; Manufacturing Systems Engineering;

    Sammanfattning : In Laser Material Processing of metals, an understanding of the fundamental absorption mechanisms plays a vital role in determining the optimum processing parameters and conditions. The absorptance, which is the fraction of the incident laser light which is absorbed, depends on a number of different parameters. LÄS MER

  3. 7. Gallium arsenide based buried heterostructure laser diodes with aluminium-free semi-insulating materials regrowth

    Författare :Carlos Angulo Barrios; KTH; []
    Nyckelord :semiconductor lasers; in-plane lasers; VCSELs; GaAs; GaInP; semi-insulating materials; hydride vapour phase epitaxy; regrowth; buried heterostructure; leakage current; simulation;

    Sammanfattning : Semiconductor lasers based on gallium arsenide and relatedmaterials are widely used in applications such as opticalcommunication systems, sensing, compact disc players, distancemeasurement, etc. The performance of these lasers can beimproved using a buried heterostructure offering lateralcarrier and optical confinement. LÄS MER

  4. 8. Microstructure and properties of welds in the lean duplex stainless steel LDX 2101

    Författare :Elin M. Westin; John Ågren; Hannu Hänninen; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Duplex stainless steel; welding; HAZ; nitrogen; manganese; microstructure; austenite formation; phase balance; precipitates; element distribution; segregation; depletion; solidification; pitting corrosion resistance; solidification; element loss; evaporation; deposition; weld oxide; thermo-mechanical simulation; thermodynamic modelling; EPMA; XPS; post-weld cleaning; pickling; Metallurgical process and manufacturing engineering; Metallurgisk process- och produktionsteknik;

    Sammanfattning : Duplex stainless steels can be very attractive alternatives to austenitic grades due to their almost double strength at equal pitting corrosion resistance. When welding, the duplex alloys normally require addition of filler metal, while the commodity austenitic grades can often be welded autogenously. LÄS MER

  5. 9. Surface integrity on post processed alloy 718 after nonconventional machining

    Författare :Jonas Holmberg; Tomas Beno; Anders Wretland; Johan Berglund; Mikael Olsson; RISE; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Alloy 718; Non-conventional machining; post processing; surface integrity; Microstructure; Residual stress; Electron back scattering diffraction; Material removal rate; Manufacturing; Surface and Joining Technology; Bearbetnings-; yt- och fogningsteknik; Production Technology; Manufacturing and materials engineering;

    Sammanfattning : There is a strong industrial driving force to find alternative production technologies in order to make the production of aero engine components of superalloys even more efficient than it is today. Introducing new and nonconventional machining technologies allows taking a giant leap to increase the material removal rate and thereby drastically increase the productivity. LÄS MER

  7. 10. New innovative methods for non-intrusive optical diagnostics of high-voltage insulator materials

    Författare :Magnus Bengtsson; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Atom- och molekylärfysik; Atomic and molecular physics; akustik; optik; optics; acoustics; Electromagnetism; Microbiology; bacteriology; virology; mycology; Mikrobiologi; bakteriologi; virologi; mykologi; fluorescence; optical diagnostics; high-voltage insulation; remote sensing; polymeric insulators; lidar; biological contamination; Gases; fluid dynamics; plasmas; Gaser; fluiddynamik; plasma; Energy research; Energiforskning; Elektromagnetism;

    Sammanfattning : The purpose of this PhD thesis work has been to develop optical techniques that can help utility engineers for assessing the state of insulators in service and in a laboratory. The possibilities to use remote laser induced fluorescence for detection and imaging of biological growth such as algae and fungi have been investigated. LÄS MER