Sökning: "low energy electron diffraction"

Visar resultat 36 - 40 av 109 avhandlingar innehållade orden low energy electron diffraction.

  1. 36. Precipitate stability in creep resistant 9-12% chromium steels

    Författare :Ardeshir Golpayegani; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; growth; precipitates; coarsening; atom probe field ion microscopy APFIM ; energy filtered TEM EFTEM ; 9-12% chromium steel;

    Sammanfattning : 9-12% chromium steels are used extensively in modern steam power plants at service temperatures up to 600°C. These materials are subjected to creep deformation during exposure which is the limiting factor in increasing the steam temperature and thus the thermal efficiency of the plants. LÄS MER

  2. 37. Scanning Tunnelling Microscopy Studies of Na Islands on Graphite, Impurity Interactions on Cu(111) and Low Temperature Structures of S/Cu(111)

    Författare :Erik Wahlström; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; photoelectron spectroscopy; Scanning tunnelling microscopy STM ; Na HOPG; scanning tunnelling spectroscopy STS ; metal quantum wells; surface impurity interaction; S Cu 111 ;

    Sammanfattning : A scanning tunnelling microscope (STM) can reveal the atomic order of a surface as well as details of its electronic structure. In the present work STM, in combination with core and valence photo-electron spectroscopy and low energy electron diffraction (LEED) was applied to three different systems: (i) simple metal quantum wells in the form of Na films and islands on highly oriented pyrolytic graphite (HOPG), (ii) low temperature S/Cu(111) structures discovered in the course of this work and (iii) impurities on Cu(111). LÄS MER

  3. 38. Surface structure and catalytic activity of Pd and Fe oxide surfaces and thin films

    Författare :Mikhail Shipilin; Synkrotronljusfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Surface X-ray diffraction SXRD ; Heterogeneous catalysis; Pd; PdO; Fe; FeO; Thin films; Fysicumarkivet A:2016:Shipilin;

    Sammanfattning : The present work is devoted to atomic scale structural studies of the surfaces of model heterogeneous catalysts relevant to oxidation reactions. A novel approach using high-energy surface X-ray diffraction combined with mass-spectrometry measurements is employed to perform in situ structural characterization of Pd(100) and Pd(553) single crystal surfaces acting as catalysts in the process of CO oxidation under semirealistic conditions. LÄS MER

  4. 39. Imaging Living Cells with an X-ray Laser

    Författare :Gijs van der Schot; Tomas Ekeberg; Janos Hajdu; Filipe Maia; Pierre Thibault; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Coherent diffractive X-ray imaging; flash X-ray imaging; lensless imaging; single particle imaging; cyanobacteria; phasing; image classification; substrate-free sample delivery; X-ray free-electron laser; XFEL; FEL; CDXI; CDI; CXI; FXI; Chemistry with specialization in Biophysics; Kemi med inriktning mot biofysik;

    Sammanfattning : Imaging living cells at a resolution higher than the resolution of optical microscopy is a significant challenge. Fluorescence microscopy can achieve a degree of super-resolution via labeling cellular components with a fluorescent dye. LÄS MER

  5. 40. Scanning tunneling microscopy and photoemission studies of Ag films on metal/semiconductor surfaces

    Författare :Samuel Starfelt; Hanmin Zhang; Lars Johansson; Anders Mikkelsen; Karlstads universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Quantum well states; thin films; semiconductor; STM; STS; ARPES; Physics; Fysik;

    Sammanfattning : The research presented in this thesis has been focused on the study of thin Ag films, grown on metal-reconstructed Si(111) and Ge(111) surfaces.The films have been grown at room temperature, and the morphologiesand electronic structures of the films have been investigated using scanning tunneling microscopy and spectroscopy (STM/STS), low-energy electron diffraction (LEED) and angle-resolved photoelectron spectroscopy(ARPES). LÄS MER