Sökning: "Gradients"

Visar resultat 11 - 15 av 597 avhandlingar innehållade ordet Gradients.

  1. 11. Modelling Band Gap Gradients and Cd-free Buffer Layers in Cu(In,Ga)Se2 Solar Cells

    Författare :Jonas Pettersson; Charlotte Platzer-Björkman; Marika Edoff; Marc Burgelman; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; CIGS; Thin film solar cells; Electrical modelling; Alternative buffer layers; Gallium gradients; Simulations; Electrical characterization; Metastabilities; Light-soaking; Hall measurements; Persistent photoconductivity; Teknisk fysik med inriktning mot elektronik; Engineering Science with specialization in Electronics;

    Sammanfattning : A deeper understanding of Cu(In,Ga)Se2 (CIGS) solar cells is important for the further improvement of these devices. This thesis is focused on the use of electrical modelling as a tool for pursuing this aim. Finished devices and individual layers are characterized and the acquired data are used as input in the simulations. LÄS MER

  3. 12. Development of Composition Gradients in Cemented Carbides

    Författare :Robert Frykholm; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; EPMA; DICTRA; functionally graded materials; gradient sintering; diffusion; APFIM; thermodynamic modelling; SEM; surface zones;

    Sammanfattning : This thesis concerns the formation of tough surface zones, depleted of cubic carbo-nitrides, in cemented carbides. Several materials with varied phase compositions, binder phase volume fraction, and carbon content have been investigated. LÄS MER

  4. 13. Population Differentiation in Solidago virgaurea along Altitudinal Gradients

    Författare :Anna Bergsten; Jon Ågren; Staffan Karlsson; Kari Lehtilä; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; population differentiation; altitudinal gradient; plant nutrient status; resorption efficiency; resorption proficiency; flowering phenology; countergradient variation; reproductive effort; flower production; cost of reproduction; Biology; Biologi; Other biology; Övrig biologi; Ecological Botany; Ekologisk botanik;

    Sammanfattning : Altitudinal gradients offer attractive opportunities for studies of population differentiation in response to environmental heterogeneity. In this thesis, I examined population differentiation along altitudinal gradients by combining common-garden experiments with field studies and experiments in alpine, subalpine and boreal populations of the perennial herb Solidago virgaurea. LÄS MER

  5. 14. Fate of riverine iron over estuarine salinity gradients

    Författare :Simon Herzog; Enhet akvatisk ekologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; iron Fe ; Organic matter; boreal rivers; XAS; DLS; Fe isotope;

    Sammanfattning : Rivers have traditionally not been considered important sources of bioavailable iron (Fe) to the marine waters, since most Fe is lost by salinity-induced aggregation and sedimentation during estuarine mixing. However, recent studies from boreal rivers found a remarkably high Fe stability, probably due to the interaction with organic matter. LÄS MER

  7. 15. Separation of cells and viruses in colloidal silica gradients

    Författare :Håkan Pertoft; Uppsala universitet; []
    Nyckelord :MEDICINE; MEDICIN;

    Sammanfattning : .... LÄS MER