Sökning: "relaxation times"

Visar resultat 1 - 5 av 110 avhandlingar innehållade orden relaxation times.

  1. 1. The response of model food webs to species loss : secondary extinctions and relaxation times

    Författare :Charlotte Borrvall; Richard Law; Linköpings universitet; []
    Nyckelord :;

    Sammanfattning : Current destruction and fragmentation of natural habitats is predicted to cause great future losses in biodiversity (Pimm et al. 1995; Hughes et al. 1997; Sala et al. 2000). LÄS MER

  3. 2. Zero-Field Splitting in Gd(III) complexes : Towards a molecular understanding of paramagnetic relaxation

    Författare :Shehryar Khan; Michael Odelius; Arnold Maliniak; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Zero-Field Splitting; Relaxation; Quantum Chemistry; Molecular Dynamics; Gd III ; kemisk fysik; Chemical Physics;

    Sammanfattning : The prime objectives of contrast agents in Magnetic Resonance Imaging(MRI) is to accelerate the relaxation rate of the solvent water protons in the surrounding tissue. Paramagnetic relaxation originates from dipole-dipole interactions between the nuclear spins and the fluctuating magnetic field induced by unpaired electrons. LÄS MER

  4. 3. Mass Transport Properties in Supramolecular Systems Studied by Diffusion and Relaxation NMR

    Författare :Patrik Jarvoll Dae; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NMR; T2; diffusion; hydrogel; exchange dynamics; T1; magnetic susceptibility; organosilica nanoparticles; microstructure; relaxation; supramolecular systems;

    Sammanfattning : This thesis shows how diffusion and relaxation NMR can be applied in various aspects to study mass transport in supramolecular systems. Information about these systems can be obtained, either by direct measurement of the molecules that are incorporated in a supramolecular structure, or via probe molecules, which indirectly gives information about the system. LÄS MER

  5. 4. Analysis of NMR Spin-lattice Relaxation Dispersion on Complex Systems

    Författare :Yang Huang; Per-Olof Westlund; Arnold Maliniak; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NMRD; relaxation theory; hydration; MD; FFC; PrxV; OEC complex; ZSM-5; BMIM [PF6; ]; fysikalisk kemi; Physical Chemistry;

    Sammanfattning : This thesis focus on the analysis of spin-lattice NMRD relaxation profilesmeasured in various complex systems such as proteins, zeolites and ionicliquids. Proton, deuterium and fluoride T1-NMRD relaxation profiles wereobtained from a fast-field cycling (FFC) instrument. LÄS MER

  7. 5. Contrast-Enhanced Magnetic Resonance Angiography - Development and optimization of techniques for paramagnetic and hyperpolarized contrast media

    Författare :Jonas Svensson; Malmö Medicinsk strålningsfysik; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; egenskaper elektriska; Kondenserade materiens egenskaper:elektronstruktur; spectroscopy; relaxation; Angiography; Magnetic resonance; Contrast-enhanced; Hyperpolarized; Condensed matter:electronic structure; 13C; supraconductors; electrical; magnetic and optical properties; magnetiska och optiska ; supraledare; magnetisk resonans; spektroskopi;

    Sammanfattning : Contrast-enhanced magnetic resonance angiography (CE-MRA) is a diagnostic method for imaging of vascular structures based on nuclear magnetic resonance. Vascular enhancement is achieved by injection of a contrast medium (CM). LÄS MER