Sökning: "first-principle calculations"
Visar resultat 11 - 15 av 39 avhandlingar innehållade orden first-principle calculations.
11. Understanding Physical Reality via Virtual Experiments
Sammanfattning : In this thesis I have studied some problems of condensed matter at high pressures and temperatures by means of numerical simulations based on Density Functional Theory (DFT).The stability of MgCO3 and CaCO3 carbonates at the Earth's mantle conditions may play an important role in the global carbon cycle through the subduction of the oceanic crust. LÄS MER
12. Chemical Transformation of Inorganic Species in Thermochemical Conversion of Waste-Derived Fuels - The Role of Oxygen Carriers
Sammanfattning : Waste-derived fuels are used increasingly in heat and power production systems in Sweden. Thermal conversion of waste-derived and biomass fuels offers the possibility of achieving carbon dioxide-neutral or even negative emissions. To limit global warming, it is essential to integrate these systems with carbon capture and storage. LÄS MER
13. Helium in CERMET fuel - binding energies and diffusion
Sammanfattning : This thesis presents a first principle approach to model helium diffusionand retention in molybdenum. Results from electron structure calculations within the framework of density functional theory are used to assess parameters in a rate theory model. LÄS MER
14. Formation stability and electronic structure of surfaces and interfaces from first principles
Sammanfattning : This thesis deals with two closely interwoven aspects of first-principle(density functional theory) materials modeling:(1)~prediction of atomic structure & chemical composition,and (2)~prediction of electronic properties.In the first part, we focus on atomic structure (AS) and chemical composition (CC) of surface and interface systems. LÄS MER
15. Metastable YAlN and ScAlN thin films : growth and characterization
Sammanfattning : ScxAl1-xN and YxAl1-xN thin films were deposited in a ultra high vacuum system using reactive magnetron co-sputtering from elemental Al, Sc and Y targets in Ar/N2. Their mechanical, electrical, optical, and piezoelectrical properties were investigated with the help of transmission electron microscopy, xray diffraction, ellipsometry, I-V and C-V measurements, and two different techniques for piezoelectric characterization: piezoresponse force microscopy and double beam interferometry. LÄS MER