Sökning: "new ag"

Visar resultat 1 - 5 av 86 avhandlingar innehållade orden new ag.

  1. 1. Surface Studies of Model Systems relevant for Pd and Ag Catalysts

    Författare :Natalia Martin; Synkrotronljusfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; High Pressure X-ray Photoelectron Spectroscopy; X-ray Photoelectron Spectroscopy; alumina; Ag; NiAl; Pd; catalysis; model system; Surface X-ray Diffraction; Low Energy Electron Diffraction; Scanning Tunneling Microscopy; Fysicumarkivet A:2014:Martin;

    Sammanfattning : This PhD thesis reports on investigations of the atomic scale structure of model catalysts relevant for the catalytic oxidation of CO and methane over Pd, and NOx reduction over silver-alumina, important reactions in automotive catalysts. By using complementary experimental techniques such as X-ray Photoelectron Spectroscopy, High Pressure X-ray Photoelectron Spectroscopy, Surface X-ray Diffraction, Low Energy Electron Diffraction, Infrared Spectroscopy, and Scanning Tunneling Microscopy, combined with theoretical calculations, the work presented in this thesis aims at an atomistic characterization of the active sites for silver-alumina and Pd model catalysts which may help to the design of new and improved catalysts. LÄS MER

  2. 2. Electronic structure and exchange interactions from ab initio theory : New perspectives and implementations

    Författare :Ramon Cardias Alves de Almeida; Olle Eriksson; Anders Bergman; Attila Szilva; R. B. Muniz; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ab initio; exchange interactions; non-collinear magnetism; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : In this thesis, the magnetic properties of several materials were investigated using first principle calculations. The ab initio method named real space linear muffin-tin orbitals atomic sphere approximation (RS-LMTO-ASA) was used to calculate the electronic structure and magnetic properties of bulk systems, surface and nanostructures adsorbed on surfaces. LÄS MER

  3. 3. Synthesis, Characterization, and Evaluation of Ag-based Electrical Contact Materials

    Författare :Fang Mao; Ulf Jansson; Mikael Olsson; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; electrical contact; bulk; coating; Ag-based alloys; Ag-based delafossite; AgI; graphene; graphene oxide; combinatorial material science; dc magnetron sputtering; friction; wear; hardness; contact resistance;

    Sammanfattning : Ag is a widely used electrical contact material due to its excellent electrical properties. The problems with Ag are that it is soft and has poor tribological properties (high friction and wear in Ag/Ag sliding contacts). LÄS MER

  4. 4. 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

  5. 5. Electrochemical detection of trace metals: from traditional techniques to new ultrathin membrane electrodes

    Författare :Kequan Xu; Gaston A. Crespo; Maria Cuartero; Tom Lindfors; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ion-selective electrodes; ion-stripping voltammetry; ultrathin membranes; interconnected ion-transfer and charge-transfer processes; trace metals; environmental waters; jonselektiva elektroder; jon-strippande voltammetri; ultratunna membran; sammankopplade jonöverförings- och laddningsöverförings-processer; spårmetaller; miljövatten; Kemi; Chemistry;

    Sammanfattning : Accurate detection of trace metals in environmental waters is an analytical challenge that is still open for the time being. The current state of the field reveals the predominance of the so-called hanging mercury drop electrode (HMDE) for multi-metal detection by means of anodic stripping voltammetry (ASV) readout. LÄS MER