Sökning: "Astrid Pundt"

Hittade 3 avhandlingar innehållade orden Astrid Pundt.

1. 1. The interaction of hydrogen with metallic glass

   Författare :Johan Bylin; Gunnar K. Pálsson; Ralph H. Scheicher; Gabriella Andersson; Astrid Pundt; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; metallic glass; hydrogen; thin film; density functional theory; stochastic quenching; molecular dynamics; x-ray diffraction; pair distribution function; neutron reflectometry; volume expansion; elastic hydrogen-hydrogen interaction; dipole force tensor; electronic structure; optical conductivity; resistivity; optical transmission; x-ray photoelectron spectroscopy; thermodynamic driving force; Gibbs free energy; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Sammanfattning : Combining theoretical ab initio calculations with high-purity thin film sample synthesis and in situ measurements is a compelling way to bridge the gap in our understanding concerning hydrogen in metallic glasses, which is the primary work of this dissertation thesis. The main emphasis has been on how hydrogen affects the structure of metallic glasses, and how those changes influence not only the electronic properties of the amorphous metals but also their thermal stability. LÄS MER

3. 2. Synthesis and Characterisation of Potential Hydrogen Storage Materials

   Författare :Emil Johansson; Björgvin Hjörvarsson; Astrid Pundt; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Hydrogen; adsorption; absorption; thermodynamics; thin films; carbon nanostructures; Fysik; Physics; Fysik;

   Sammanfattning : The dissociative and non-dissociative hydrogen uptake in carbon nanostructures and metallic films were investigated by measurements and analysis of solubility isotherms. The total, non-dissociative, uptake for multi-walled nano-barrels and amorphous nanoporous carbon was determined to be 6.2 and 4.2 wt. LÄS MER

4. 3. Thermodynamics of Hydrogen in Confined Lattice

   Författare :Xin Xiao; Hjörvarsson Björgvin; Max Wolff; Astrid Pundt; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; thermodynamics hydrogen superlattice;

   Sammanfattning : Three of the most important questions concerning hydrogen storage in metals are how much hydrogen can be absorbed, how fast it can be absorbed (or released) and finally how strongly the hydrogen is bonded. In transition metals hydrogen occupies interstitial sites and the absorption as well as desorption of hydrogen can be fast. LÄS MER