Sökning: "Rietveld refinement"

Visar resultat 1 - 5 av 14 avhandlingar innehållade orden Rietveld refinement.

  1. 1. Crystal chemistry of Fe-Ti oxides in mafic rocks and metabasites: A study aimed at refinement of geological tools and interpretations

    Författare :Benyam Estifanos; Berggrundsgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Fe-Ti oxide; hercynite; siderite; stilpnomelane; olivine corona; Swedish Caledonides; hysteresis; PIXE; synchrotron XRD; Rietveld; microprobe; red corundum; palaeomagnetism; eclogite; plagioclase clouding; dolerite; pyroxene gneiss; Geology; physical geography; Geologi; fysisk geografi;

    Sammanfattning : This thesis consists of four subprojects: (A) ‘Clouding of plagioclase by Fe-Ti oxides’, (B) ‘Fe-Ti oxides during high-pressure metamorphism of mafic rocks’, (C) ‘Magnetic study of Fe-Ti oxides in mafic rocks and metabasites’, and (D) ‘Topotactic phase transitions in oxide minerals’. A) In southern Sweden dolerite dikes and gabbros with clouded plagioclase are common. LÄS MER

  2. 2. Acceptor-Doped BaZrO3 Perovskite: Synthesis, Structure and Proton Conductivity

    Författare :Istaq Ahmed; Chalmers University of Technology; []
    Nyckelord :Impedance spectroscopy; Perovskite; Neutron diffraction; Rietveld refinement; BaZrO3.; Proton conductor;

    Sammanfattning : Acceptor-doped perovskite oxides exhibit significant proton conductivity in hydrogen containing atmospheres. Therefore, they have potential for use as separator materials for various electrochemical devices including gas sensors, electrolysers and fuel cells. LÄS MER

  3. 3. The rational design of lithium insertion materials for battery applications

    Författare :Helena Berg; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; Chemistry; cathode materials; lithium manganese oxide; in situ neutron diffraction; Rietveld refinement; band-structure calculations; Kemi; Chemistry; Kemi; Inorganic Chemistry; oorganisk kemi;

    Sammanfattning : The transition-metal oxide spine1 LiMn2O4 is a promising cathode material for high-capacity lithium-ion batteries. Structure-property relationships pertaining to the electrochemical cycling behaviour of LiMn2O4 have been studied. LÄS MER

  4. 4. Proton conductivity in acceptor-doped lanthanide based pyrochlore oxides

    Författare :Karinh Eurenius; Göteborgs universitet; Göteborgs universitet; Gothenburg University; []
    Nyckelord :Pyrochlore; Rietveld refinement; Proton conductivity; Electrical impedance spectroscopy; Concentration Cell Electromotive Force Method.;

    Sammanfattning : A high interest in developing new materials for SOFC applications in the temperature range of approximately 200–500 C has been growing lately. The lower activation energies for proton (H+) mobility can give higher conductivity in this temperature range. LÄS MER

  5. 5. Structure and Phase Stability of CaC2 Polymorphs, Li2C2 and Lithium Intercalated Graphite : A Revisit with High Pressure Experiments and Metal Hydride–Graphite Reactions

    Författare :Sumit Konar; Ulrich Häussermann; Gunnar Svensson; Arnold Guloy; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; acetylide carbides; high pressure; Raman spectroscopy; powder X-ray diffraction; Rietveld refinement; materialkemi; Materials Chemistry;

    Sammanfattning : Alkali (A) and alkaline earth (AE) metals can form carbides and intercalated graphites with carbon. The carbides mostly represent acetylides which are salt-like compounds composed of C22− dumbbell anions and metal cations. Both the acetylide carbides and intercalated graphites are technologically important. LÄS MER