Sökning: "density of states"

Visar resultat 16 - 20 av 391 avhandlingar innehållade orden density of states.

  1. 16. 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

  3. 17. Doping and Density of States Engineering for Organic Thermoelectrics

    Författare :Guangzheng Zuo; Martijn Kemerink; Ergang Wang; Mariano Campoy-Quiles; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Thermoelectric materials can turn temperature differences directly into electricity. To use this to harvest e.g. waste heat with an efficiency that approaches the Carnot efficiency requires a figure of merit ZT larger than 1. LÄS MER

  4. 18. Estimation of risk in the field of osteoporosis

    Författare :Helena Johansson; Göteborgs universitet; []
    Nyckelord :osteoporosis; fracture; bone mineral density; ; clinical risk factors; FRAX; Poisson model; 10 year probability; mortality; vitamin D; adiponectin;

    Sammanfattning : Introduction: Osteoporosis has been recognised as an established and well-defined disease that affects more than 75 million people in the United States, Europe and Japan. Osteoporosis has been operationally defined by the WHO on the basis of bone mineral density (BMD) assessment. LÄS MER

  5. 19. Low temperature specific heat determinations and calculations of the density of states at the Fermi level

    Författare :Mats Larsson; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP;

    Sammanfattning : .... LÄS MER

  7. 20. Topological states of matter in low dimensions

    Författare :Christian Spånslätt; Eddy Ardonne; Thors Hans Hansson; Karsten Flensberg; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; teoretisk fysik; Theoretical Physics;

    Sammanfattning : A central theme in condensed matter physics is the classification and characterization of states of matter. In the recent decades, it has become evident that there exists a large class of quantum mechanical systems that must be classified according to properties deeply rooted in the mathematical field of topology, rather than in terms of which symmetries they break. LÄS MER