Sökning: "hydrogen isotopes"

Visar resultat 1 - 5 av 22 avhandlingar innehållade orden hydrogen isotopes.

  1. 1. Adsorption of Molecular Hydrogen on Cu, Pd and Ni Surfaces

    Författare :Krister Svensson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; electron energy loss spectroscopy; nickel; molecular chemisorption; hydrogen; palladium; physisorption; photodesorption; copper;

    Sammanfattning : This thesis is devoted to spectroscopic studies of molecular hydrogen adsorbed on metal surfaces. Hydrogen is the simplest molecule available and is a very valuable model adsorbate. From a spectroscopic point of view there are also three easily accessible molecular isotopes, H2, HD and D2, with widely different masses. LÄS MER

  3. 2. Paleoclimate and seasonality on Sumatra during the Late Glacial and Holocene : Insights from biomarkers and climate model simulations

    Författare :Lars Petter Hällberg; Malin Kylander; Frederik Schenk; Rienk Smittenberg; David Naafs; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Holocene; Late Glacial; biomarkers; organic geochemistry; climate model; hydrogen isotopes; stable isotopes; paleoclimate; alkanes; GDGT; brGDGT; H-GDGT; bacterial community shifts; paleothermometry; precipitation reconstruction; peat; geokemi; Geochemistry;

    Sammanfattning : Deep atmospheric convection in the Indo-Pacific Warm Pool (IPWP) is a key driver of the Hadley and Walker Circulations that modulate the Asian-Australian monsoons and the El Niño Southern Oscillation (ENSO). Temperature and rainfall seasonality, i.e. LÄS MER

  4. 3. A combined carbon and hydrogen isotope approach to reconstruct the SE Asian paleomonsoon : Impacts on the Angkor Civilization and links to paleolimnology

    Författare :Kweku Kyei Afrifa Yamoah; Rienk Smittenberg; Sarah Feakins; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Holocene; summer monsoon; biomarkers; hydrogen isotopes; lake sediment; peat; Thailand; geokemi; Geochemistry;

    Sammanfattning : Changes in monsoon patterns not only affect ecosystems and societies but also the global climate system in terms of heat energy and humidity transfer from the equator to higher latitudes. However, understanding the mechanisms that drive monsoon variability on longer timescales remains a challenge, partly due to sparse paleoenvironmental and paleoclimatic data. LÄS MER

  5. 4. 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

  7. 5. Hydrogen Impurities and Dislocations in Transition Metals

    Författare :Björn von Sydow; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Motion of impurities and dislocations is essential for many material properties of metals. In the present thesis we have made use of different atomistic simulation techniques to study the behavior of hydrogen and edge dislocations in transition metals. We have carried out molecular-dynamics (MD) simulations for hydrogen diffusion in niobium. LÄS MER