Pulsed field gradient stimulated echo

Fig. 2. 500 MHz pulsed field gradient stimulated echo spectra of a mixture of choline chloride, acetone and TSP in D2O, obtained using the LED sequence as described in the text. A signal from an unidentified impurity is visible just to high field of the acetone resonance.

To determine permeability distributions, experiments are conducted whereby fluid is injected into saturated samples. A pulsed-field-gradient stimulated-echo technique is used to resolve the velocity field within the sample. An inverse problem is formulated and solved to determine the permeability distribution. 

Pulsed-field-gradient stimulated-echo experiments were used to determine the velocity distribution during flowing experiments. An inverse problem was formulated and solved to determine estimates of the permeability distribution. 

PSTE Pulsed field gradient stimulated echo ROE Rotating-frame NOE RTIL Room-temperature ionic liquid Tf2N Bis(trifluoromethylsulfonyl)amide TSIL Task-specific ionic liquid... 

In porous media, the molecules diffuse in restricted space with tortuous pathways and the apparent mobility reduces when the observation time increases. Thus, it is of interest to study the time evolution of the diffusion coefficient. In this circumstance, the pulsed field gradient stimulated echo (PFGSTE) is introduced as shown in Fig. 4 [7]. Here, the refocusing 180° RF pulse is replaced by two 90° RF pulses separated by a time interval A. 

Cotts, R.M., Hoch, M.J.R., Sun, T. and Markert, J.T. (1989) Pulsed field gradient stimulated echo methods for improved NMR diffusion measurements in heterogeneous systems. J. Magn. Reson., 83(2), 252-266. 

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