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Visar resultat 1 - 5 av 207 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. NMR diffusion studies on lyotropic liquid crystalline systems

    Författare :Greger Orädd; Frank Volke; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Diffusion; pulsed field gradient; liquid crystalline systems; lipid lateral diffusion; cubic phases; peptide-lipid interactions; hydrophobic mismatch; permeability;

    Sammanfattning : The pulsed field gradient fourier transform nuclear magnetic resonance (PFG-FTNMR) method to measure translational diffusion coefficients in multicomponent systems has been applied to amphiphilic molecules forming liquid crystalline phases.By analyzing the concentration dependence of the diffusion coefficients of water and amphiphile in a micellar system of N,N-dimethyldodecy lamine oxide (DDAO) in water it was possible to conclude that the micelles formed were polydisperse in size and shape. LÄS MER

  3. 2. Microstructure and liquid mass transport control in nanocomposite materials

    Författare :Christoffer Abrahamsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; magnetic alignment; permeability; colloidal gels; microgels; bond water; clay; flow; microstructure; nanocomposites; poly N-isopropylacrylamide ; porous materials; liquid mass transport; diffusion; diffusion NMR; particle aggregation; phase behavior; silica;

    Sammanfattning : Some of the biggest problems currently facing the world are closely tied to unsolved technological challenges in the material sciences. Many materials have a porous microstructure that controls their overall properties. LÄS MER

  4. 3. Transport Coefficients during Drying of Solids containing Multicomponent Mixtures

    Författare :Rafael Gamero; Joaquín Martínez; Evangelos Tsotsas; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; capillary; conduction; convection; diffusion; evaporation; heat transfer; hydraulic conductivity; liquid film; liquid transport; mass transfer; Maxwell-Stefan diffusion coefficients; molar fluxes; phase equilibrium; temperature gradient; ternary mixture; thermodynamic factors; Chemical engineering; Kemiteknik;

    Sammanfattning : This study investigated the transport coefficients involved in mass and heat transfer during the drying of a porous solid partially saturated with multicomponent mixtures.  It included the coefficients governing liquid transport through the solid, the matrix of multicomponent diffusion coefficients in the liquid phase, and the effective thermal conductivity. LÄS MER

  5. 4. Developing novel diffusion MRI methods for comprehensive analysis of restricted and anisotropic self-diffusion system

    Författare :Hong Jiang; Fysikalisk kemi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; MRI; diffusion; tissue microstructure; heterogeneity; diffusion encoding; q-vector; ;

    Sammanfattning : Diffusion MRI is a non-invasive imaging technique used to study the microstructural properties of biological tissues by observing the self-diffusion of water molecules. Traditional diffusion MRI methods, based on the pulsed gradient spin-echo sequence, employ magnetic field gradients to encode information about translational motion. LÄS MER

  7. 5. Development of Novel Diffusion NMR Methods : Preclinical Applications in Colloidal Model Systems

    Författare :Stefanie Eriksson; Fysikalisk kemi; []
    Nyckelord :diffusion NMR; diffusion tensor; Microscopic anisotropy; q-MAS; exchange; liquid crystals; yeast cell suspensions;

    Sammanfattning : NMR is a powerful non-invasive technique utilizing radiofrequency and gradient pulses to manipulate the spinsof atomic nuclei. In particular, diffusion NMR uses strong magnetic field gradients to label the positions of spins allowing for the measurement of translational motion of molecules in liquids. LÄS MER