Sökning: "fotosyntes"

Visar resultat 11 - 15 av 55 avhandlingar innehållade ordet fotosyntes.

  1. 11. Mimicking Photosystem II with Manganese Model Complexes to Approach Artificial Photosynthesis

    Författare :Joakim Högblom; Biokemi och Strukturbiologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Metabolism; Hydrogen; EPR; Cobalt; Biokemi; metabolism; Biochemistry;

    Sammanfattning : The work in thesis aims for artificial photosyntesis, which could and will mimic natural photosynthesis, the process that uses light to create energy rich compounds from H2O and CO2. Water is oxidized in Photosystem II (PSII) by the Water Oxidizing Complex (WOC), which is a catalytic site on the lumenal side of the thylakoid membrane. LÄS MER

  3. 12. Excited State Processes in Solar Energy Materials

    Författare :Tomas Österman; Kemisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Solar cells; Conjugated polymers; Charge transfer state; Time-resolved spectroscopy; Fluorescence; Artificial Photosynthesis; Bis-tridentate ruthenium II -complexes; Density functional theory; Quantum chemistry.;

    Sammanfattning : This dissertation covers studies of excited state processes in two types of solar energy materials: alternating polyfluorene polymers and their blends with fullerenes in the active layer of plastic solar cells, and bis-tridentate RuII-polypyridyl complexes to be used as sensitizer in systems for artificial photosynthesis. The polymer:fullerene blends were studied by transient absorption and time-resolved fluorescence measurements in order to investigate the role of the charge transfer (CT) state in charge formation. LÄS MER

  4. 13. Monitoring climate and plant physiology using deuterium isotopomers of carbohydrates

    Författare :Angela Augusti; Jürgen Schleucher; Vaughan Hurry; Howard Griffiths; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Climate reconstruction; deuterium; elevated CO2; isotopomer; nuclear magnetic resonance; photorespiration; tree-ring cellulose.; Plant physiology; Växtfysiologi;

    Sammanfattning : Climate is changing and it is certain that this change is due to human activities. Atmospheric greenhouse gases have been rising in an unprecedented way during the last two centuries, although the land biosphere has dampened their increase by absorbing CO2 emitted by anthropogenic activities. LÄS MER

  5. 14. Towards Artificial Photosynthesis: Exploration of Efficient First-Row Transition Metal-Based Water Oxidation Catalysts

    Författare :Lizhou Fan; Licheng Sun; Thomas Wågberg; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Artificial photosynthesis; Water oxidation; Heterogeneous catalyst; Electrochemistry; Electronic structure; Kemi; Chemistry;

    Sammanfattning : Artificial photosynthesis provides a promising strategy for sustainable energy harvesting, yet its overall efficiency is limited by the water oxidation reaction. The subject of this thesis focuses on the exploration of highly efficient cost-effective heterogeneous catalysts for water oxidation, and the investigation of essential catalyst structure-activity relationships. LÄS MER

  7. 15. Stress responses of Arabidopsis plants with a varying level of non-photochemical quenching

    Författare :Hanna Johansson Jänkänpää; Stefan Jansson; Barbara Demmig-Adams; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Arabidopsis; NPQ; PsbS; photosynthesis; field experiment; metabolomics; Physiological Botany; fysiologisk botanik; molekylärbiologi; Molecular Biology;

    Sammanfattning : When light energy input exceeds the capacity for photosynthesis the plant need to dissipate the excess energy and this is done through non-photo-chemical quenching (NPQ). Photochemical quenching (photosynthesis), NPQ and fluorescence are three alternative faiths of excited chlorophylls. PsbS associates to photosystem II and is involved in NPQ. LÄS MER