Sökning: "bond water"

Visar resultat 1 - 5 av 204 avhandlingar innehållade orden bond water.

1. 1. Time-resolved Structural and Mechanistic Studies of Water Oxidation in Photosystem II : water here, water there, water everywhere

   Författare :Casper de Lichtenberg; Johannes Messinger; Wolfgang P. Schröder; Holger Dau; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Oxygenic Photosynthesis; Photosystem II; TR-MIMS; isotope exchange; EPR; EDNMR; water splitting; water oxidation;

   Sammanfattning : Oxygenic photosynthesis is undisputedly one of the most important chemical processes for human life on earth as it not only fills the atmosphere with the oxygen that we need to breathe, but also sustains the accumulation of biomass, which is not only used as nourishment but is also present in almost every aspect of our lives as building material, textiles in clothes and furniture, or even as living decorations to name a few.The photosynthetic water-splitting mechanism is catalyzed by a water:plastoquinone oxido-reductase by the name of photosystem II (PSII), which is embedded in the thylakoid membranes of plants, algae and cyanobacteria. LÄS MER

3. 2. Core Level Spectroscopy of Water and Ice

   Författare :Dennis Nordlund; Anders Nilsson; Martin Wolf; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; x-ray adsorption spectroscopy; photoemission spectroscopy; x-ray photoelectron spectroscopy; platinum; x-ray emission spectroscopy; density functional theory; hydrogen-bonded; H-bond; water; ice; electronic structure; excited state dynamics; proton dynamics; water adsorption; liquid water; Physics; Fysik;

   Sammanfattning : A core level spectroscopy study of ice and water is presented in this thesis. Combining a number of experiments and spectrum calculations based on density functional theory, changes in the local valence electronic structure are shown to be sensitive to the local H-bonding configurations. LÄS MER

4. 3. Probing unoccupied electronic states in aqueous solutions

   Författare :Lars-Åke Näslund; Anders Nilsson; Hendrik Bluhm; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; x-ray absorption; x-ray absorption spectroscopy; XAS; NEXAFS; water; liquid water; aqueous solution; hydrogen bond; hydrogen bond network; local geometry; Physics; Fysik;

   Sammanfattning : Water is one of the most common compounds on earth and is essential for all biological activities. Water has, however, been a mystery for many years due to the large number of unusual chemical and physical properties, e.g. decreased volume during melting and maximum density at 4 °C. LÄS MER

5. 4. Catalytic Water Production from First-Principles Calculations

   Författare :Gustav Karlberg; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; platinum; Monte Carlo; first-principles; hydroxyl; transition metals; density functional theory DFT ; Metropolis; oxygen; water; water production reaction; hydrogen;

   Sammanfattning : The main subject of this thesis is the catalytic water production reaction on metal surfaces. This reaction is of great current interest due to its importance in fuel cells, a clean and efficient way to convert chemical energy into electrical. LÄS MER

7. 5. Cellulose-water interaction: a spectroscopic study

   Författare :Erik L Lindh; István Furó; Lennart Salmén; Lisbeth G Thygesen; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; cellulose; water; hydrogen exchange; deuterium; NMR spectroscopy; FT-IR spectroscopy; Kemi; Chemistry;

   Sammanfattning : The human society of today has a significantly negative impact on the environment and needs to change its way of living towards a more sustainable path if to continue to live on a healthy planet. One path is believed to be an increased usage of naturally degradable and renewable raw materials and, therefore, attention has been focused on the highly abundant biopolymer cellulose. LÄS MER