PFGSE pulsed field gradient spin echo

Abbreviations D, self-diffusion coefficient ge, gradient-echo IR, inversion recovery IRFT, inversion recovery fourier transform MRS, magnetic resonance spectroscopy PD, proton density PFGSE, pulsed field gradient spin echo se, spin-echo. 

PFGSE pulsed-field-gradient spin-echo... 

We finish this section by comparing our results with NMR and incoherent neutron scattering experiments on water dynamics. Self-diffusion constants on the millisecond time scale have been measured by NMR with the pulsed field gradient spin echo (PFGSE) method. Applying this technique to oriented egg phosphatidylcholine bilayers, Wassail [68] demonstrated that the water motion was highly anisotropic, with diffusion in the plane of the bilayers hundreds of times greater than out of the plane. The anisotropy of... 

The Pulsed Field Gradient Spin Echo (PFGSE)... 

We saw in Chapter 8 how a selective 180° pulse can be placed between two gradients of the same sign and duration to give a pulsed field gradient spin echo (PFGSE) that not only selects the desired coherence but also destroys any other coherences. First, we use a hard 90° pulse to create coherence on all spins, and then the first gradient twists the coherence into a helix (Fig. 8.21). The selective 180° pulse reverses the direction of twist in... 

The pulsed (field) gradient-spin echo (PFGSE or PGSE) experiment is used to measure translational diffusion constants [29] (which must not be confused with spin diffusion). It is based on the two-pulse spin-echo experiment (Fig. 12 Sec.II.E.l), with the addition of two field-gradient periods to create a spatial frame of reference in the x and y dimensions. The first gradient is applied between the two pulses the second, between the 180°... 

From such a background, the structure and dynamics of the main chain and side chains of LC polymers have been sophisticatedly characterized by solid-state NMR and pulse field-gradient spin-echo (PFGSE) NMR to understand an important role for formation of the thermotropic liquid crystals [21-25], Details of these works will be introduced. 

PBpT-012 in the nematic LC phase at 160°C is mechanically stretched to obtain highly-oriented fibers by cooling at room temperature. The nature of the channels with a diameter of about 3 nm in polyester fibers may be expected as one of materials with separation function. The nature of the inside of the fibers has been clarified through the observation of the diffusion coefficients of probe small-size molecules, methane and ethane, in direction parallel and perpendicular to the long channel by means of pulse field-gradient spin-echo(PFGSE) H NMR spectroscopy [34, 35],... 

Figure 7-36. Spin echo H NMR spectra of PG-18 in the thermotropic LC phase at 80°C as a function of field-gradient pulse length d by PFGSE NMR...

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