Sökning: "Defekter och diffusion"

Visar resultat 1 - 5 av 8 avhandlingar innehållade orden Defekter och diffusion.

  1. 1. Insights into Materials Properties from Ab Initio Theory : Diffusion, Adsorption, Catalysis & Structure

    Författare :Andreas Blomqvist; Rajeev Ahuja; Christopher Wolverton; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Density functional theory; Molecular dynamics; Diffusion; Catalysis; Adsorption; Random structure search; Hydrogen-storage materials; Phase-change materials; Defects and diffusion; Defekter och diffusion; Surfaces and interfaces; Ytor och mellanytor; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : In this thesis, density functional theory (DFT) calculations and DFT based ab initio molecular dynamics simulations have been employed in order to gain insights into materials properties like diffusion, adsorption, catalysis, and structure. In transition metals, absorbed hydrogen atoms self-trap due to localization of metal d-electrons. LÄS MER

  3. 2. Simulation of relaxation processes in complex condensed matter systems : Algorithmic and physical aspets

    Författare :Tomas Oppelstrup; Mikhail Dzugutov; Göran Wahnström; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Condensed matter physics; Kondenserade materiens fysik; Numerical analysis; Numerisk analys; Materials science; Teknisk materialvetenskap; Defects and diffusion; Defekter och diffusion;

    Sammanfattning : This thesis summarizes interrelated simulation studies of three different physical phenomena. The three topics are: simulation of work hardening of materials using dislocation dynamics, investigation of anomalous diffusion in supercooled liquids using molecular dynamics,and kinetic Monte-Carlo simulation of annealing of radiation damaged materials. LÄS MER

  4. 3. Light Scattering Effects in Transparent Wood Biocomposites

    Författare :Hui Chen; Lars Berglund; Ilya Sychugov; Max Yan; Mikael Sjödahl; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Transparent wood; cellulose; biocomposite; light transmission; anisotropic scattering; Rayleigh scattering; photon budget; photon diffusion theory; light-transparent wood interaction; Transparent trä; cellulosa; biokomposit; ljustransmission; anisotropisk spridning; Rayleigh-spridning; fotonbudget; fotondiffusionsteori; ljus-transparent trä interaktion; Fiber- och polymervetenskap; Fibre and Polymer Science;

    Sammanfattning : Transparent wood (TW) shows interesting optical properties and offers a sustainable alternative to petroleum-based polymer glasses. The influence of the TW internal structure (e.g. LÄS MER

  5. 4. Materials Reliability in PEM Fuel Cells

    Författare :Live Mølmen; Peter Leisner; Ulf Jansson; Jönköping University; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fuel cell; PEMFC; Bipolar plate; Catalyst; Electrodeposition; Corrosion; Stainless steel; Accelerated stress tests; bränsleceller; PEM; bipolära plattor; katalysator; elektroplätering; korrosion; accelererad testning;

    Sammanfattning : As part of the global work towards reducing CO2 emissions, all vehicles needs to be electrified, or fueled by green fuels. Batteries have already revolutionised the car market, but fuel cells are believed to be a key energy conversion system to be able to electrify also heavy duty vehicles. LÄS MER

  7. 5. Atomistic modelling of functional solid oxides for industrial applications : Density Functional Theory, hybrid functional and GW-based studies

    Författare :Cecilia Århammar; Rajeev Ahuja; Steven Louie; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; density functional theory; oxides; GW; Condensed matter physics; Kondenserade materiens fysik; Magnetism; Magnetism; Defects and diffusion; Defekter och diffusion;

    Sammanfattning : In this Thesis a set of functional solid oxides for industrial applications have been addressed by first principles and thermodynamical modelling. More specificially, measurable quantities such as Gibbs free energy, geometry and electronic structure have been calculated and compared when possible with experimental data. LÄS MER