Exchange experiments solid state

Knagge K, Smith JR, Smith LJ, Buriak J, Raftery D (2006) Analysis of porosity in porous silicon using hyperpolarized 129Xe two-dimensional exchange experiments. Solid State Nucl Magn Reson 29 85-89... 

FBgh-resolution 2D NMR pulse sequences can be based on information transfer via homonuclear or heteronuclear scalar coupling, dipolar relaxation or chemical exchange while solid-state 2D NMR experiments normally use dipolar coupling in place of scalar coupling. There are three basic modes of spectral... 

Adlerhas investigated the behaviour of LSC porous electrodes by AC impedance spectroscopy and has found that the oxygen reduction reaction is limited by surface chemical exchange and solid state diffusion, contrary to the commonly accepted view that the electrode reactions are charge transfer limited. Furthermore he has also found that the reduction reaction extends over several micrometres and under certain conditions may approach the thickness of the electrode. Isotope exchange measurements on dense LSC deposited on a Ceo.9Cao.iOi,9 electrolyte were performed by Kawada et These experiments showed that the... 

The following set of suggested experiments describes the preparation of solid-state and liquid ion-exchange ion-selective electrodes, as well as potentiometric biosensors. 

As a consequence of restricted internal mobility in molecules in the crystalline state, nuclei in different conformation environments, but identical in other respects, can produce different signals in 13C cross polarization, magic angle spinning (CPMAS) solid-state NMR. This analysis is not necessarily limited to crystalline regions, since signals of different conformations are resolved if the exchange is slow with respect to the time scale of the NMR experiment. 

Using the OPENCORE NMR spectrometer, standard solid-state NMR experiments have been demonstrated in Ref. 2. They include 1H-13C CPMAS with TPPM decoupling, 13C-15N dipolar recoupling under MAS, 1H FSLG, 13C-13C 2D exchange, and so on. Here we show two more examples, where the spectrometer was used to implement standard pulse sequences, but in somewhat demanding circumstances in terms of sensitivity. 

In addition to X-ray crystallographic studies, two-dimensional NMR solution experiments (i.e., COSY, 1D-NOE, and NOESY, discussed in Sections 3.5.9 and 3.5.10) have been carried out on many lanthanide(III), Ln(ffl), chelate complexes to confirm that the structure of the MRI imaging agent, used in aqueous solution, will correspond to the solid-state X-ray crystallographic structure. Two-dimensional exchange spectroscopy (2D-EXSY) has been applied to lanthanide chelates to study the dynamics of conformational equilibria (how acetate arms chelate and how... 

During the flight of droplets in the spray, the forced convective and radiative heat exchanges with the atomization gas lead to a rapid heat extraction from the droplets. A droplet undergoing cooling and phase change may experience three states (a) fully liquid, (b) semisolid, and (c) fully solid. If the Biot number of a droplet in all three states is smaller than 0.1, the lumped parameter model 1561 can be used for the calculation of droplet temperature. Otherwise, the distributed parameter model 1541 should be used. 

For the most part, exchange experiments in the solid state use either chemical shift anisotropy (for spin4) or quadrupole coupling (for spin > i) under static conditions, i.e. no sample spinning, to generate frequencies uj and 102 that depend on molecular orientation. The projections onto the two spectral frequency axes are then the corresponding powder patterns resulting from the... 

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