Sökning: "Crystallites"

Visar resultat 21 - 25 av 43 avhandlingar innehållade ordet Crystallites.

  1. 21. Nanostructured materials for gas sensing applications

    Författare :Kristina Buchholt; Per Eklund; Lars Hultman; Anita Lloyd Spetz; Harry L. Tuller; Linköpings universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP;

    Sammanfattning : In this Thesis I have investigated the use of nanostructured films as sensing and contact layers for field effect gas sensors in order to achieve high sensitivity, selectivity, and long term stability of the devices in corrosive environments at elevated temperatures. Electrochemically synthesized Pd and Au nanoparticles deposited as sensing layers on capacitive field effect devices were found to give a significant response to NOx with small, or no responses to H2, NH3, and C3H6. LÄS MER

  3. 22. Sintering of nickel catalysts in the presence of NH3/H2

    Författare :Johan Lif; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; stabilisation; hydrogen; nickel; ammonia; alumina; sintering; DFT calculation; catalyst deactivation;

    Sammanfattning : Supported metal catalysts are used in many important industrial processes, where amination of alcohols is one example. The exposure of the supported metal catalyst to reaction conditions results usually to a decrease in catalytic activity, by for instance thermal degradation. LÄS MER

  4. 23. Preparation, structure and properties of Hg, Tl-containing high-temperature superconductors

    Författare :Martin Valldor; Stephen Berger; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; oorganisk kemi; Inorganic Chemistry;

    Sammanfattning : Powder samples with the general composition (Tl,Hg)2(Ba,Sr)2(Sr,Ca)Cu2O8-d, abbreviated 2212, were synthesised by solid-state reaction of metal oxides in closed silica ampoules. Depending on the relative amounts of Ba, Sr, and Ca, the superconducting transition temperature, Tc, varied significantly (45-100 K). LÄS MER

  5. 24. Structure formation at solid/liquid interfaces : Understanding self-assembly and environmental challenges

    Författare :Shirin Nouhi; Adrian R. Rennie; Vassilios Kapaklis; Maja S. Hellsing; Ann Terry; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Solid liquid interface; neutron scattering; colloidal particles; self-assembly; perfluoroalkyl substance; Moringa seed proteins; adsorption; lamellar disorder; thermal fluctuations.;

    Sammanfattning : The work described in the present dissertation has explored the structure of particles and molecules at solid/liquid interfaces, aiming to understand the physics of self-organizing systems and use this knowledge to address some environmental issues. Surface-sensitive neutron scattering techniques, such as reflectometry and grazing incidence small angle scattering, have been used as the primary tool to investigate structures in proximity to an interface. LÄS MER

  7. 25. Effects of grinding variables on structural changes and energy conversion during mechanical activation using line profile analysis (LPA)

    Författare :Parviz Pourghahramani; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mineralteknik; Mineral Processing;

    Sammanfattning : The mechanical treatment of solids is one of the most common and widely used operations with which man has been concerned from the very beginnings of history of civilization. At the present, mechanical activation has a wide range of application potential. LÄS MER