Sökning: "DFT"

Visar resultat 11 - 15 av 404 avhandlingar innehållade ordet DFT.

  1. 11. Density Functional Theory Calculations of Graphene based Humidity and Carbon Dioxide Sensors

    Författare :Karim Elgammal; Anna Delin; Biplab Sanyal; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; DFT; graphene; sensors; Quantum Espresso; ab-initio; Fysik; Physics;

    Sammanfattning : Graphene has many interesting physical properties which makes it useful for plenty of applications. In this work we investigate the possibility of using graphene as a carbon dioxide and humidity sensor. LÄS MER

  3. 12. Nonlocal Correlations in Density Functional Theory

    Författare :Henrik Rydberg; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; bonding; GGA; adhesion; graphene; DFT; exchange; adsorption; LDA; first principles; polarization; vdW; determinants; correlation; graphite; surface states; van der Waals; density-functional theory; physisorption; nonlocal; functional;

    Sammanfattning : In Density Functional Theory, the widely used local and semilocal approximations to the exchange-correlation energy, the local density approximation (LDA) and the generalized gradient approximations (GGAs), lack a physical description of truly nonlocal correlation effects, which are absolutely essential for a proper description of soft matter. A scheme is proposed that provides a basis for systematic improvements beyond LDA and GGA, including correlations at intermediate and long range, giving rise to bonds of pure van der Waals type as well as more intricate, intermediate-range correlation bonds. LÄS MER

  4. 13. Dynamics and Reactivity of Cu-species in Cu-CHA for NH3-SCR

    Författare :Joachim Bjerregaard; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Machine Learning Force Field; Diffusion; Cu-CHA; NH3-SCR; DFT; Sulfur Deactivation;

    Sammanfattning : Copper exchanged chabazite (Cu-CHA) is a state-of-the-art catalyst for deNOx via ammonia assisted selective catalytic reduction (NH3-SCR) in lean burn engines, owing to its good low-temperature activity, and high hydrothermal stability. One challenge for Cu-CHA is, however, the sensitivity to sulfur species, which are present in the exhaust gas. LÄS MER

  5. 14. 5-Aminolevulinic acid and derivatives thereof : properties, lipid permeability and enzymatic reactions

    Författare :Edvin Erdtman; Leif Eriksson; Tore Brinck; Örebro universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; 5-Aminolevulinic acid; tautomerization; PDT; DFT; MM; QM MM; Porphobilinogen synthase; Uroporphyrinogen III decarboxylase; membrane penetration; enzyme mechanism; Biophysical chemistry; Biofysikalisk kemi; Quantum chemistry; Kvantkemi; Theoretical chemistry; Teoretisk kemi; Fysikalisk kemi; Physical Chemistry; Biochemistry; Biokemi;

    Sammanfattning : 5-aminolevulinic acid (5-ALA) and derivatives thereof are widely usedprodrugs in treatment of pre-malignant skin diseases of the cancer treatmentmethod photodynamic therapy (PDT). The target molecule in 5-ALAPDTis protoporphyrin IX (PpIX), which is synthesized endogenously from5-ALA via the heme pathway in the cell. LÄS MER

  7. 15. Theoretical modelling of thin film growth in the B-N system

    Författare :Björn Mårlid; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemistry; Boron nitride; boron; theoretical modelling; DFT; surface processes; surfaces; thin films; growth ALD; Kemi; Chemistry; Kemi; Inorganic Chemistry; oorganisk kemi;

    Sammanfattning : In vapour phase deposition, the knowledge and control of homogeneous and heterogeneous reactions in connection to precursor design may lead to the deposition of the desired material; structure or phase. This thesis is a document attempting to increase the knowledge of film growth in the B-N system. LÄS MER