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Nuclear magnetic resonance (NMR) spectroscopy and NMR imaging require a sample to be positioned in a homogeneous magnetic field inside a strong magnet. The instrumentation is large, and the sample […]

Test samples of LDPE (low-density polyethylene) were electrically aged until PD (partial discharge) and electrical treeing occurred. Investigations on the spatial distribution of microscopic domain sizes in the lameliar morphology of the samples were carried out applying a novel method of proton NMR imaging which probes magnetization transfer by spin diffusion. Spatial changes of LDPE morphology are detected due to the appearance of PD.

Measures the residual dipolar couplings by hydrogen dipolar-encoded longitudinal magnetization, double and triple-quantum nuclear magnetic resonance (NMR) in cross-linked elastomers. Correlation with cross-link density; Reconversion of multiple quantum coherences.

The NMR spin-diffusion process-taking place in morphology represented by three different domains with arbitrary sizes and diffusivities is investigated. The effects of large changes in the size of the interface domain and the spin-diffusion coefficients of this domain on the spin-diffusion decay and build-up curves were analyzed by numerical simulations.

A novel scheme is presented for the measurement of two-dimensional stochastic magnetic resonance spectra. The excitation consists of a time-shifted sum of noise signals at the Larmor frequency. Longitudinal magnetization is detected in the audiofrequency regime so that excitation and response are well decoupled for accessing large bandwidths. Because noise excitation saves RF power, the method shows promise for applications in the spectroscopic detection of magnetic resonance signals from large objects. [ABSTRACT FROM AUTHOR]