Sökning: "periodic structure"

Visar resultat 16 - 20 av 165 avhandlingar innehållade orden periodic structure.

  1. 16. On the Structure and Dynamics of Polyelectrolyte Gel Systems and Gel-surfactant Complexes

    Författare :Per Johan Råsmark; Christer Elvingson; Johan Bergenholtz; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physical chemistry; polyelectrolyte gel; microgel; dynamic light scattering; Raman spectroscopy; periodic boundary conditions; percolation; hypersphere; Monte Carlo; Brownian dynamics; Fysikalisk kemi; Physical chemistry; Fysikalisk kemi;

    Sammanfattning : This thesis describes the results of experimental work on polyelectrolyte gels and their interaction with oppositely charged surfactants, and presents two new algorithms applicable to the simulation of colloid and polymer systems.The model systems investigated were crosslinked poly(acrylate) (PA) and poly(styrene sulphonate) (PSS), and the surfactant was dodecyl trimethylammonium bromide (DoTAB). LÄS MER

  3. 17. Sterically stabilised liposomes and related lipid aggregates : Fundamental studies on aggragate structure and stability

    Författare :Markus Johnsson; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; liposome; steric stabilisation; colloidal stability; cryo-TEM; drug delivery; Fysik; Physics; Fysik; Physical Chemistry; fysikalisk kemi;

    Sammanfattning : Various aspects of and approaches towards the steric stabilisation of liposomes have been investigated, mainly by use of fluorescence techniques and cryo-transmission electron microscopy (cryo-TEM). It is shown that PEG(2000)-lipids can be incorporated in the liposome membrane up to a critical concentration of 8-10 mol% without any observable structural perturbations. LÄS MER

  4. 18. Theory of Bonding and Structure of Materials

    Författare :Uno Yxklinten; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The main topic of this Thesis is total-energy calculations of metallic systems, with and without adsorbates or impurities. In this Effective-Medium Theory the expression for the total energy of a system of interacting atoms is divided into three terms. In this thesis all three terms have been re- investigated and improved. LÄS MER

  5. 19. The Multimodal Transfer Matrix Method : And its application to higher-symmetric periodic structures

    Författare :Pilar Castillo-Tapia; Oscar Quevedo-Teruel; Paolo Bacarelli; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : This thesis focuses on the understanding and computation of the dispersion properties of periodic structures possessing higher symmetries with the multimodal transfer matrix method (MMTMM). Periodic structures with higher symmetries are invariant after additional symmetry operations over the translation operation. LÄS MER

  7. 20. Optical Studies of Periodic Microstructures in Polar Materials

    Författare :Herman Högström; Carl Gustaf Ribbing; Clivia M. Sotomayor Torres; Uppsala universitet; []
    Nyckelord :Engineering physics; polaritonic; polar; photonic crystal; surface phonon polariton; multilayer; Reststrahlen; SiC; SiO2; Teknisk fysik;

    Sammanfattning : The optical properties of matter are determined by the coupling of the incident electromagnetic radiation to oscillators within the material. The oscillators can be electrons, ions or molecules. Close to a resonance the dielectric function exhibits strong dispersion and may be negative. LÄS MER