Sökning: "Dispersion"

Visar resultat 1 - 5 av 804 avhandlingar innehållade ordet Dispersion.

  1. 1. Dispersion Engineering : Negative Refraction and Designed Surface Plasmons in Periodic Structures

    Författare :Zhichao Ruan; Min Qiu; Henri Benisty; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; photonic crystal; dispersion property; negative refraction; surface plasmon polariton; designed surface plasmon; negative index material; layer-KKR method; finite-difference time-domain method; plane wave method; subwavelength imaging; open cavity; enhanced transmission; slowing light; Photonics; Fotonik;

    Sammanfattning : The dispersion property of periodic structures is a hot research topic in the last decade. By exploiting dispersion properties, one can manipulate the propagation of electromagnetic waves, and produce effects that do not exist in conventional materials. LÄS MER

  2. 2. Changing population distribution in Sweden : long term trends and contemporary tendencies

    Författare :Johan Håkansson; Umeå universitet; []
    Nyckelord :SOCIAL SCIENCES; SAMHÄLLSVETENSKAP; SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Population distribution; redistribution; Sweden; geographical levels; concentration; dispersion; accessibility; migration; natural population change; age composition; Population Distribution; Concentration; Dispersion; Accessibility; Migration; Natural increase;

    Sammanfattning : The aim of the thesis is to describe and analyse the population redistribution in Sweden at different geographical levels from the beginning of the 19th century to the end of the 20th century. The analysis is approached in three different ways. First, the redistribution at different geographical levels is analysed (papers I and II). LÄS MER

  3. 3. Theoretical Investigation into Longitudinal Dispersion in Natural Rivers — A Scaling Dispersion Model

    Författare :Zhi-Qiang Deng; Avdelningen för Teknisk vattenresurslära; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; soil mechanics; Väg- och vattenbyggnadsteknik; Environmental technology; pollution control; Miljöteknik; kontroll av utsläpp; offshore technology; hydraulic engineering; Civil engineering; Scaling dispersion.; Parameter estimation; Numerical scheme; Dispersion coefficient; Natural river;

    Sammanfattning : Using a broad variety of scientific methods this dissertation systematically investigates the fundamental mechanisms underlying the dispersion processes in natural rivers and their mathematical descriptions in a geometrical framework. Emphasis is on the geometrical variations and irregularities of a natural river and their scales. LÄS MER

  4. 4. InP-based photonic crystals : Processing, Material properties and Dispersion effects

    Författare :Audrey Berrier; Srinivasan Anand; Alfred Forchel; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; Photonic crystals; indium phosphide; photonic bandgap; Bloch modes; slow light; dispersion; coupled cavity waveguides; chemically assisted ion beam etching; lag effect; cavities; optical losses; carrier transport; carrier lifetimes; negative refraction; photonic bandstructure; Physics; Fysik;

    Sammanfattning : Photonic crystals (PhCs) are periodic dielectric structures that exhibit a photonic bandgap, i.e., a range of wavelength for which light propagation is forbidden. The special band structure related dispersion properties offer a realm of novel functionalities and interesting physical phenomena. LÄS MER

  5. 5. First-principles calculations of long-range intermolecular dispersion forces

    Författare :Auayporn Jiemchooroj; Bo E. Sernelius; Irina Yakimenko; Linköpings universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; van der Waals forces; dispersion forces; intermolecular interactions; dispersion coefficients; polarizability; Physics; Fysik;

    Sammanfattning : This work presents first-principles calculations of long-range intermolecular dispersion energies between two atoms or molecules as expressed in terms of the C6 dipole-dipole dispersion coefficients. In a series of publications, it has been shown by us that the complex linear polarization propagator method provides accurate ab initio and first-principles density functional theory values of the C6 dispersion coefficients in comparison with those reported in the literature. LÄS MER