Not only in low-field nuclear magnetic resonance, Laplace inversion is a relevant and challenging topic. Considerable conceptual and technical progress has been made, especially for the inversion of data encoding two decay dimensions. Distortion of spectra by overfitting of even moderate noise is counteracted requiring a priori smooth spectra.
View Article and Find Full Text PDFDue to improved quantification capabilities and enhanced signal-to-noise ratio (SNR), phase-corrected real reconstruction in magnetic resonance imaging is superior to the common magnitude reconstruction, especially at low SNR. This requires the development of an automated phase-correction algorithm. Existing methods are not well suited for multiple unconnected regions of very low SNR.
View Article and Find Full Text PDFThe biofilm-forming fungus, Aureobasidium pullulans DSM 2404, was grown in a bead-packed reactor. Alterations within the reactor were analysed in several cross-sectional slices by magnetic resonance imaging (MRI) with flow contrast. For the first time, biofilm accumulation could be continuously elucidated without using any contrast agents, and the non-stationary flow through the fixed-bed reactor could be visualized.
View Article and Find Full Text PDFMagn Reson Imaging
February 2005
Applying MRI techniques to low-density fibrous filter media provides us with unique information about the initial structure and deposited mass within the same filter sample. This now enables us to obtain the necessary link between structure and deposition for validation and further enhancement of modeling filtration kinetics. However, additional work is needed before achieving a realistic understanding of filtration kinetics.
View Article and Find Full Text PDFAn approach is presented that allows NMR relaxation rates to be determined for a complex mixture, and it is applied to a dimethyl sulfoxide/water solution. This approach is novel for such systems, having only been used for simple systems such as atomic liquids or atomic ions in liquids until now. It involves use of a predetermined, quantum mechanical, multidimensional property surface in a simulation.
View Article and Find Full Text PDFJ Magn Reson
December 2003
Pulse sequences consisting of adiabatic pulses for total through-bond correlation spectroscopy (TOBSY) under magic-angle spinning (MAS) are introduced. Above a certain threshold, the polarization transfer achieved with these sequences is largely insensitive to the amplitude and homogeneity of the radiofrequency field employed. An experimental transfer efficiency of up to 76% was achieved in a two-spin system using the sequence WiW9(24)(1) at a MAS frequency of 26.
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