Sökning: "relaxation parameters"

Visar resultat 1 - 5 av 168 avhandlingar innehållade orden relaxation parameters.

1. 1. Theory of water-proton spin relaxation in complex biological systems

   Författare :Zhiwei Chang; Biofysikalisk kemi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; spin relaxation theory; immobilized macromolecules; magnetic relaxation dispersion; integral longitudinal relaxation rate; stochastic Liouville equations; multi-spin systems; cross-mode relaxation; spectral density functions;

   Sammanfattning : In complex biological systems (e.g. gels, cross-linked proteins and biological tissues), the longitudinal spin relaxation of water protons is primarily induced by exchange-mediated orientational randomization (EMOR) of intra- and intermolecular magnetic dipole-dipole couplings. 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. Pushing diffusion MRI towards new dimensions

   Författare :Joao Martins; Fysikalisk kemi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NMR; MRI; diffusion; relaxation; multidimensional diffusion MRI; relaxation-diffusion correlations; Laplace NMR; porous media; tissue microstructure; heterogeneity; anisotropy;

   Sammanfattning : Diffusion-MRI techniques allow the non-invasive investigation of microstructural changes in living tissues. However, a detailed interpretation of the data is complicated by the fact that multiple microscopic environments with varying diffusion properties all contribute to the measured signal. LÄS MER

5. 4. Laboratory and stellar spectroscopy of the complex ions Fe+, Mo+, Th+ and U+

   Författare :Hampus Nilsson; Astronomi - Genomgår omorganisation; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; molybdenum; iron; thorium; uranium.; Atomic and molecular physics; Atom- och molekylärfysik; Astronomy; space research; cosmic chemistry; Astronomi; rymdvetenskap; kosmisk kemi; Condensed matter:electronic structure; electrical; spektroskopi; magnetisk resonans; supraledare; magnetiska och optiska ; egenskaper elektriska; Kondenserade materiens egenskaper:elektronstruktur; spectroscopy; relaxation; magnetic resonance; magnetic and optical properties; supraconductors; astrophysics; radiative lifetimes; oscillator strengths; term analysis; Fourier transform spectroscopy; branching fractions; Fysicumarkivet A:2002:Nilsson;

   Sammanfattning : The new generation of high resolution astronomical instruments such as the Hubble Space Telescope (HST) or the Very Large Telescope (VLT) has renewed the demand for accurate atomic parameters like wavelengths, oscillator strengths and line profiles accompanied by reliable uncertainty estimates. Fourier transform spectroscopy has proven to be a powerful tool when measuring these parameters. LÄS MER

7. 5. 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