Sökning: "degree of polarization."

Visar resultat 6 - 10 av 56 avhandlingar innehållade orden degree of polarization..

  1. 6. Scanning Tunneling Microscopy Induced Luminescence Studies of Semiconductor Nanostructures

    Författare :Ulf Håkanson; Fasta tillståndets fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; transmission electron microscopy TEM ; III-V semiconductors; low-dimensional structures; nanostructures; single dot spectroscopy; Stranski-Krastanow; quantum dot QD ; Semiconductory physics; polarization; ordering; InP; GaInP; photon mapping; scanning tunneling microscopy STM ; scanning tunneling luminescence STL ; Halvledarfysik; Fysicumarkivet A:2003:Håkanson;

    Sammanfattning : This thesis treats scanning tunneling luminescence (STL) investigations of semiconductor nanostructures. The STL technique combines scanning tunneling microscopy (STM) with detection of photons, induced by the tunneling electrons. The high spatial resolution in STM and the local excitation allow for optical investigations on the nanometer-scale. LÄS MER

  3. 7. Magnetism and Structure of Thin 3d Transition Metal Films : XMCD and EXAFS using Polarized Soft X-Rays

    Författare :Anders Hahlin; Dimitri Arvanitis; Olof Karis; Claus Schneider; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; thin film; xmcd; exafs; anisotropy; coherence; circular polarization; magnetism; Fe; Co; Ag; Fysik; Physics; Fysik; Fysik; Physics;

    Sammanfattning : In this Thesis the magnetic and structural properties of thin epitaxial Fe, Co, and Ni films are discussed. Some of the in-situ prepared samples were used to characterize the degree of circular polarization of the newly installed beamline D1011 at MAX-lab. LÄS MER

  4. 8. Electrical Characterization of Partial Discharge Resistant Enamel Insulation

    Författare :Tuan Anh Hoang; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Enamel wire insulation; dipolar polarization; charge injection; charge transport; chromium oxide; dc conductivity; partial discharge; twisted pair.; dielectric permittivity;

    Sammanfattning : Adjustable speed drives for rotating machines have become increasingly popular as they provide possibilities of smooth and accurate process control as well as for energy savings. In such systems, due to the fact that the voltage applied at terminals of motor windings is no longer purely sinusoidal but characterized by a high content of harmonics, the appearing electrical and thermal stresses yield premature failures of the winding insulation, mainly because of an increased partial discharge (PD) activity. LÄS MER

  5. 9. Polarization-resolved photoluminescence spectroscopy of III-nitride quantum dots

    Författare :Supaluck Amloy; Fredrik Karlsson; Per-Olof Holtz; Jørn M. Hvam; Linköpings universitet; []
    Nyckelord :;

    Sammanfattning : In this thesis, results from studies on (In)GaN quantum dots (QDs) are presented, including investigations of the structural, optical and electronic properties. The experimental studies were performed on GaN and InGaN QDs grown by molecular beam epitaxy, taking advantage of the Stranki-Krastanov growth mode for the GaN QD samples and the composition segregation for the InGaN QD samples. LÄS MER

  7. 10. The Fate of Electronically Excited States : Ultrafast Electron and Energy Transfer in Solvated Donor-Acceptor Systems

    Författare :Staffan Wallin; Leif Hammarström; Jan Davidsson; Eric Vauthey; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physical chemistry; Electron transfer; Energy transfer; Anisotropy; Porphyrin; Ruthenium tris-bipyridine; Superexchange; Supramolecular; Donor-Acceptor; Charge transfer state; S2 state; Ultrafast; Fysikalisk kemi; Physical chemistry; Fysikalisk kemi;

    Sammanfattning : Processes where a molecule absorbs visible light and then disposes of the excess energy via electron/energy transfer reactions have an important role both in nature (e.g. in photosynthesis) and in many technical applications (e.g. LÄS MER