Decay of magnetization

The pulse sequence for ICP experiments appears simple a 90° proton pulse is followed immediately by a spin lock radio-frequency (rf) field of strength B that is phase shifted by 90° relative to the first pulse. By a spin-lock field is meant a strong rf field B that is on resonance with the given nucleus it keeps magnetization in a spin-locked orientation parallel to the B direction where the decay of magnetization is governed by T p. At present the strong continuous B field is replaced by multipulse sequences that are well known from other spin-lock experiments such as TOCSY, ROESY etc. Simultaneously,... 

Figure 4 Exponential decay of magnetic field S in the surface layer of thickness 3. of a Type I superconducting slab cylinder in an applied magnetic field Sapp parallel to its surface (from Ref. 8, p. 135)...

Fig. 2 Plot of the results of a multiple-contact time experiment of neotame polymorphic forms A and G showing buildup and decay of magnetization as a function of contact time. (From Ref. l)...

Fig. 10.3.9 Spin diffusion in LDPE. (a) Spin-diffusion curves showing the decay of magnetization in the mobile chain segments as a function of distance across the sample. The symbols I and II mark the regions unaffected and affected by the electrical ageing process, respectively, (b) Representative magnetization decays from regions I and II. Their different shapes indicate different morphologies. Dots experimental values. Solid lines Simulations.

The black line shows the decay of magnetization due to the action of a gradient pulse. The grey line is an approximation, valid at long times, for the envelope of the decay. 

E9-10. Use the formula given in section 9.6.2 for the overall decay of magnetization during a gradient... 

To obtain information about the polymer, a material parameter imaging is used. Different properties can be utilized to provide image contrast without adding other substances. Such properties include the relaxation times Ti (relaxation time of longitudinal magnetization decay, spin-lattice relaxation) and T2 (relaxation time of transversal magnetization decay, spin-spin relaxation), as well as the chemical shift. Frequently, the decay of magnetization is measured. For liquids, a simple... 

A model first presented by Street and Woolley (1949) has been widely used to interpret measurements of the time decay of magnetization. This model presumes that reversal occurs by thermal activation over an energy barrier which has a broad distribution of barrier heights. Street and Woolley showed that this assumption leads to a time dependence of magnetization M t) given by... 

Transverse relaxation (also called spin-spin relaxation) is a process that describes the decay of magnetization in the x y plane. This corresponds to the relaxation time T 2. 

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