Sökning: "Carbon"
Visar resultat 6 - 10 av 3431 avhandlingar innehållade ordet Carbon.
6. Lowcoordinated Silicon and Hypercoordinated Carbon : Structure and Stability of Silicon Analogs of Alkenes and Carbon Analogs of Silicates
Sammanfattning : Quantum chemical studies on lowcoordinated group 14-16 compounds have been performed. This thesis focuses particularly on silenes influenced by reverse Siδ-=Cδ+ bond polarization. Hypercoordinated carbon compounds are also studied. LÄS MER
7. Carbon-based magnetic nanomaterials
Sammanfattning : Magnetism of carbon-based materials is a challenging area for both fundamental research and possible applications. We present studies of low-dimensional carbon-based magnetic systems (fullerene-diluted molecular magnets, carbon nanotubes, graphite fluoride, and nanoporous carbon) by means of SQUID magnetometer, X-ray diffraction and vibrational spectroscopy, the latter techniques used as complementary instruments to find a correlation between the magnetic behaviour and the structure of the samples. LÄS MER
8. Chemistry of Carbon Nanostructures : Functionalization of Carbon Nanotubes and Synthesis of Organometallic Fullerene Derivatives
Sammanfattning : This thesis is based on two main parts. The first part concerns purification and functionalization of carbon nanotubes (papers I-III), and the second part is related to the synthesis of organometallic fullerene derivatives (papers IV-VII): Two oxidative methods involving aqueous nitric acid were compared with respect to their capability to introduce carboxylic groups into single walled carbon nanotubes, and several literature methods for esterification and amidation of these groups have been evaluated with focus on efficiency and reproducibility in forming covalently functionalized products soluble in organic media. LÄS MER
9. Beyond carbon-limitation : A re-evaluation of the ecological role of photorespiration and direct oxygen photoreduction in seagrasses
Sammanfattning : Seagrasses living in shallow coastal waters are regularly subjected to changes in environmental conditions including the two essential factors for photosynthesis: dissolved inorganic carbon (DIC) and irradiance. This thesis focuses on the photosynthetic responses of seagrasses to carbon limitation induced by community metabolism and/or high light intensities. LÄS MER
10. Permafrost carbon in a changing Arctic : On periglacial landscape dynamics, organic matter characteristics, and the stability of a globally significant carbon pool
Sammanfattning : Organic matter (OM) in arctic permafrost ground contains about twice as much carbon (C) as is currently present in the atmosphere. Climate change is particularly strong in the Arctic, and could cause a considerable part of the OM in permafrost to thaw out, decompose, and be released as greenhouse gases; further enhancing global warming. LÄS MER
