Sökning: "structure diffusion"

Visar resultat 6 - 10 av 537 avhandlingar innehållade orden structure diffusion.

1. 6. Electronic Structure Calculations of Point Defects in Semiconductors

   Författare :Andreas Höglund; Susanne Mirbt; Alison Mainwood; Uppsala universitet; []
   Nyckelord :Physics; electronic structure calculations; point defects; semiconductor; formation energy; equilibrium solubility limit; thermodynamic equilibrium concentration; transfer levels; negative-U; 110 surface; diffusion; activation energy; solar cells; Fysik;

   Sammanfattning : In this thesis point defects in semiconductors are studied by electronic structure calculations. Results are presented for the stability and equilibrium concentrations of native defects in GaP, InP, InAs, and InSb, for the entire range of doping conditions and stoichiometry. LÄS MER

3. 7. Small Molecule Diffusion in Spherulitic Polyethylene : Experimental Results and Simulations

   Författare :Alessandro Mattozzi; Ulf W. Gedde; Alan H. Windle; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; diffusion; polyethylene; poly ethylene-co-octene ; free volume; morphology; intermediate phase; spherulite; Monte Carlo simulation; Polymer chemistry; Polymerkemi;

   Sammanfattning : The diffusion of small-molecule penetrants in polyethylene is hindered by impenetrable crystals and by the segmental constraints imposed by the crystals on the penetrable phase. Liquid and vapour n-hexane sorption/desorption measurements were performed on metallocene catalyzed homogenous poly(ethylene-co-octene)s. LÄS MER

4. 8. On the determination of diffusion coefficients in bone

   Författare :Abdallah Shokry; Hållfasthetslära; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Kalman filter; Mathematical model; Spatially dependent diffusion; Diffusion in bone; Diffusion coefficient; Conductivity; Elastic modulus; Porous materials;

   Sammanfattning : Diffusion in bone is needed for bone remodeling and bone healing. Understanding the phenomenon is often important for comprehension bone diseases. Mathematical modeling of the diffusion processes is a required prerequisite in the study of this important physical process in living bone tissue. LÄS MER

5. 9. Geochronology of impact structures - constraining syn- and post-impact processes using the 40Ar/39Ar and U-Pb techniques

   Författare :Maria Herrmann; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Impact structure; Dating impact events; 40Ar 39Ar dating; U-Pb dating; Siljan impact structure; Mien impact structure; Hummeln impact structure; Puchezh-Katunki impact structure;

   Sammanfattning : The discovery, at the beginning of the 20th century, that elements can transform into other elements, due to the spontaneous decay of an instable to a stable atomic nuclei, gave rise to a powerful source for age information in many fields of earth science. For impact structures, it is crucial to establish well-defined and precise ages in order to understand how impact events affect the Earth’s geo and biosphere and also with regard to possible future events that can have devastating effects on our civilization. LÄS MER

7. 10. Diffusion of Water in Foods during Heating

   Författare :Karin Thorvaldsson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; diffusion; mass transfer; mass transport; porous; water; moisture; heat; food;

   Sammanfattning : The overall aim of this research was to improve the knowledge of diffusion of water in foods during heating, so that the final quality of foods after heat processing could be predicted and controlled. The work consisted of three main parts. The first part involved the development of a method to study the diffusion. LÄS MER