Sökning: "Spectral stability"

Visar resultat 6 - 10 av 87 avhandlingar innehållade orden Spectral stability.

  1. 6. The Dirac Operator; From Numerics to the Theory of G-convergence

    Författare :Hasan Almanasreh; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Dirac operator; spuriousity; cubic Hermitian; stability parameter; G-convergence; ¡-convergence; spectral measure; quadratic form; stability parameter;

    Sammanfattning : We consider two main issues concerning the Dirac operator, the first is widely known as the appearance of spurious eigenvalues within the spectrum. The second is the study of the asymptotic behavior of the eigenvalues for a family of Dirac operators with oscillatory potential added to the Coulomb-Dirac Hamiltonian. LÄS MER

  3. 7. Electrolyte-Based Dynamics: Fundamental Studies for Stable Liquid Dye-Sensitized Solar Cells

    Författare :Jiajia Gao; Lars Kloo; Elizabeth Gibson; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Dye-sensitized solar cells; Stability; Electrolyte; Cobalt redox couples; Additives; Kemi; Chemistry;

    Sammanfattning : The long-term outdoor durability of dye-sensitized solar cells (DSSCs) is still a challenging issue for the large-scale commercial application of this promising photovoltaic technique. In order to study the degradation mechanism of DSSCs, ageing tests under selected accelerating conditions were carried out. LÄS MER

  4. 8. High order summation-by-parts methods in time and space

    Författare :Tomas Lundquist; Jan Nordström; Peter Eliasson; David A. Kopriva; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; summation-by-parts; time integration; stiff problems; weak initial conditions; high order methods; simultaneous-approximation-term; finite difference; discontinuous Galerkin; spectral methods; conservation; energy stability; complex geometries; non-conforming grid interfaces; interpolation;

    Sammanfattning : This thesis develops the methodology for solving initial boundary value problems with the use of summation-by-parts discretizations. The combination of high orders of accuracy and a systematic approach to construct provably stable boundary and interface procedures makes this methodology especially suitable for scientific computations with high demands on efficiency and robustness. LÄS MER

  5. 9. Color Tuning for Perovskite Light-Emitting Diodes

    Författare :Hongling Yu; Feng Gao; Xiaoke Liu; Olle Inganäs; Fengling Zhang; Maksym V. Kovalenko; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Perovskite light-emitting diodes; Color tuning; Pure and mixed halide; Spectral stability; White emission;

    Sammanfattning : Metal halide perovskites (MHPs) are recognized as promising semiconductor materials for a variety of optical and electrical device applications due to their cost-effective and outstanding optoelectronic properties. As one of the most significant applications, perovskite light-emitting diodes (PeLEDs) hold promise for future lighting and display technologies, attributed to their high photoluminescence quantum yield (PLQY), high color purity, and tunable emission color. LÄS MER

  7. 10. Dynamics in Blue Emitting Metal Halide Perovskites for Light Emitting Diodes

    Författare :Max Karlsson; Feng Gao; Tze Chien Sum; Barry P. Rand; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Perovskites; Light-emitting diodes; Stability; Efficiency;

    Sammanfattning : Lighting comprises a large part of the global electricity consumption as of today, and the use of lighting in illumination and displays is only projected to grow. It is therefore imperative to meet this energy demand, not only by means of greener energy production, but also with materials that are both more efficient to fabricate as well as to use. LÄS MER