Sökning: "generalized gradient approximation"

Visar resultat 11 - 15 av 15 avhandlingar innehållade orden generalized gradient approximation.

  1. 11. Density functional calculations of optical spectra and narrow band systems

    Författare :Anna Delin; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Fysik; Physics; Fysik; Fysik; Physics;

    Sammanfattning : A calculational method, based on density functionaltheory, has been used to calculate optica spectra for a wide range of systems,as well as ground-state properties of some narrow-band systems. A systematic study of the trends in the optical properties of the 4Brefractory metal compounds has been performed. LÄS MER

  3. 12. First Principle Studies of Functional Materials : Spintronics, Hydrogen Storage and Cutting Tools

    Författare :Fredrik Silvearv; Ahuja Rajeev; Ali Zaoui; Uppsala universitet; []
    Nyckelord :spintronics; hydrogen storage; coating materials; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : The properties of functional materials have been studied with density functional theory. The first type of materials that have been investigated is the so called diluted magnetic semiconductors. It is a new class of materials that could offer enhanced functionality by making use of spin in addition to the charge of the electron. LÄS MER

  4. 13. Theory of Bonding and Structure of Materials

    Författare :Uno Yxklinten; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The main topic of this Thesis is total-energy calculations of metallic systems, with and without adsorbates or impurities. In this Effective-Medium Theory the expression for the total energy of a system of interacting atoms is divided into three terms. In this thesis all three terms have been re- investigated and improved. LÄS MER

  5. 14. Tree-based machine learning methods with non-life insurance applications

    Författare :Henning Zakrisson; Mathias Lindholm; Filip Lindskog; Julien Trufin; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; matematisk statistik; Mathematical Statistics;

    Sammanfattning : Non-life insurance is a field which has been data-driven for a long time, with the statistical framework behind modern-day actuarial sciences laid out at the beginning of the 20th century. Problems regarding the estimation and prediction of risk are relevant to the insurance industry specifically, but also for society as a whole. LÄS MER

  7. 15. Ab initio study of transition metal carbides and actinide compounds

    Författare :Weiwei Sun; Pavel Korzhavyi; Igor Di Marco; Börje Johansson; Leon Petit; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Computational material science; material physics; Materials Science and Engineering; Teknisk materialvetenskap;

    Sammanfattning : Two classes of materials are investigated using ab intio methods based on density functional theory. The structural properties, electronic structure and thermodynamic properties of binary and ternary transition metal carbides are discussed in details. In addition, two actinide compounds will be presented. LÄS MER