Nuclear magnetization decay

Measurement, in time domain, of the rate of nuclear magnetization decay towards equilibrium following the excitation by... 

Nuclide HalFlife Natural Nuclear Magnetic Decay Decay... 

Figure 2.29. Dependence of -IgTj on Tgof oligomer components, taken from summarized nuclear magnetization decay curves, measured for single phase systems of cis-polyisoprene otioxyethylene-a, ffl-dimetacrylate (1) and tetramethylene- , -dimetacrylate (3), butadiene-nilrile copolymer with tetramethylene-a, -dimetacrylate (2) and cis-polybutadiene with a, -dimetaciylate-bis-(trioxyethylene)-adipinate (4).

The authors of book [277] proposed an original method of analysis of the nuclear magnetization decay curves taking into account their non-exponential form and dependence on diffusion time. This method explained some characteristics of oligomer and polydisperse polymer self-diffusion earlier, all the experimental results were contradictory [277-281], and they were beyond the existing self-diffusion theories [32,250],... 

Nuclear magnetic Decay of a pulse Large Difficult None time at known position Change in nuclear spin solutions Good works when... 

There is, in addition, another generally different time required to specify the radiofrequency behavior of the nuclear spin system. This time is called the transverse relaxation time and is the time constant for the exponential decay of the transverse (x and y) components of nuclear magnetization M- and M ... 

Nuclear Magnetic Resonance (NMR) Spectroscopy. Longitudinal and transverse relaxation times (Ti and T2) of 1H and 23Na in the water-polyelectrolytes systems were measured using a Nicolet FT-NMR, model NT-200WB. T2 was measured by the Meiboom-Gill variant of the Carr-Purcell method (5). However, in the case of very rapid relaxation, the free induction decay (FID) method was applied. The sample temperature was changed from 30 to —70°C with the assistance of the 1180 system. The accuracy of the temperature control was 0.5°C. 

Nuclear magnetic resonance studies of methane hydrate dissociation suggest that intrinsic kinetics is not likely to play a dominant role in the dissociation process (Gupta et al., 2006). Methane hydrate dissociation was shown to progress in the absence of an intermediate state (or activated state), with no preferential decay of large to small cavities. Similar measurements have been performed for Xe hydrate dissociation (Moudrakovski et al., 2001b). 

This discussion of acetone is closed without going into detail concerning the various radical reactions at room temperature. Many of them must occur and the overall mechanism is believed to be well understood. Any mechanism which necessarily involves so many steps probably never could be proved to be correct in its entirety. The points we wish to emphasize are mainly that dissociation can occur in more than one way, sometimes from one electronic state and sometimes from another. The relative importances of the various steps are difficult to determine but studies of emission decay, of intermediate concentrations by flash photolysis, and of the yields of all of the products by modern methods such as chromatography and nuclear magnetic resonance permit reasonable mechanisms to be proposed. 

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