Sökning: "PIXE"
Visar resultat 11 - 15 av 17 avhandlingar innehållade ordet PIXE.
11. Chemical and Morphological Characterisation of Aerosol Particles in the Tropopause Region
Sammanfattning : The aim of this work was to study atmospheric aerosols, focusing on the chemical composition, the morphology and the origin of the aerosol in the upper troposphere and lowermost stratosphere. An aerosol sampler was developed for this purpose. A new method for quantitative analysis of the major components of the aerosol, i.e. LÄS MER
12. Volcanic Aerosols in the Upper Troposphere and Stratosphere – Aircraft- and Satellite-Based Observations
Sammanfattning : Volcanic eruptions are the largest source of variability in the stratospheric particle concentration as they inject SO2 that is subsequently converted into sulphate particles. No major perturbation of the stratospheric aerosol load has been observed since the large eruption of Pinatubo in 1991, but several moderate eruptions after 2000 have caused deviations from stratospheric background conditions. LÄS MER
13. Early Palaeozoic jawed polychaetes with focus on polychaetaspids and ramphoprionids from the Silurian of Gotland, Sweden
Sammanfattning : Jawed polychaete annelid worms were abundant and diverse in the early Palaeozoic seas and their jaws (scolecodonts) are common microfossils in sedimentary rocks of that age. Despite their abundance, relatively little work has been focused on these fossils. LÄS MER
14. Carbothermal synthesis of nano-structured metal, carbides and nitrides, using solution processed precursors; from precursor to product
Sammanfattning : This thesis describes how solution chemical based carbothermal syntheses can be used for the synthesis of nanostructured zirconium carbide and nitride nanophase powders as well as a nickel-metal coating on NbC for use as a sintering agent. The focus is on the development of novel synthesis routes using atomic or small nanoscale level mixing of the metal oxide and carbon source in the starting precursors, enabling the use of lower synthesis temperatures and non-agglomerated nanosized powders. LÄS MER
15. Low and High Energy Ion Beams in Nanotechnology
Sammanfattning : In this thesis, two ways of fabrication of nanometer-sized semiconductor features are presented. Low Energy Ion Implantation (LEII) has been used to create shallow (sub-50 nm) and laterally small (5 m m – 200 nm) features by 10 keV As+ doping of B background doped Si. LÄS MER
