Selectively inverting

Figure 12 The C responses (bottom) obtained by selectively inverting H5 (bound to a car on 12), they lead to the cross-relaxation rates erH C6 and cl1. A reference carbon-13 spectrum is shown at the top.

Fig. 11.7 a Pulse sequence for rotational-resonance recoupling of homonuclear spin pairs, b The spinning frequency is matched to the isotropic chemical-shift difference, and one of the resonances is selectively inverted and the polarization exchange measured as a function of the mixing time, c The difference polarization as a function of the mixing can be evaluated to give the dipolar coupling constant. 

These initial slopes are readily evaluated since we can measure the signal corresponding to Igq (or Seq if S is a nuclear spin) and, since the relevant instrumental factor is identical to the one which prevails in the measurement of leq (or Seq). Moreover, initial conditions can be devised for determining separately one of the three relaxation parameters 7 (, or a. The simplest experiment consists of selectively inverting one of the two magnetizations. Consider first the selective inversion of I magnetization for which the following initial conditions hold 72(0) = —leg and S2(0) = Seq. This yields for the initial slopes... 

Subsequently, Uhrinova et al.29 reconsidered the problem using both proton-and carbon-detected experiments. For example, couplings of anomeric carbons were measured from the 13C satellites in proton NMR spectra. The critical factor in these methods is the suppression of signals from protons bound to, 2C atoms. In the pulse-sequence proposed, these protons were selectively inverted by a BIRD (Bilinear Rotation Decoupling) pulse,30 and the spin-echo method introduced by Bendall et al.31 was used. 

The experiment is very simple—one line of a multiplet is selectively inverted (by a selective 180° pulse of duration r) immediately before the usual non-selective read pulse is applied and the FID sampled. The Fourier transform then yields the whole spectrum with altered line intensities. Populations of the energy levels connected by the selectively irradiated line are changed (inverted) by the selective pulse, and this leads to changes in... 

After experimenting with inverted, noninverted, and dual-gate a-Si H TFT prepared with quasi-ohmic Ti-Al source-drain contacts, the author selected inverted TFTs with Ti-Al top contacts (see Fig. 6) for the active matrix. 

This technique has been recently used in a study of the photolysis of Cs with extremely encouraging results (4-7). A relatively broad band was found which selectively inverted the product populations in the 5D(3/2) and 6P(l/2) states to such an extent that even continuous laser action should be sustained by those products with adequate optical pumping at wavelengths within that band. In addition, the detail that was found was sufficient to locate three new repulsive states of Cs and to correlate them with their atomic limits ( ). Those results are reviewed here for comparison to new data obtained for the... 

Frequencies and intensities of the iines in the two-dimensional 7-spectrum of an AB spin system when both spins experience the same 180 non-selective inverting pulse (45)... 

ROESY-TOCSY experiment Selective inverse detection of C-H correlation Scalar heteronuclear recoupled interaction by multiple pulse Simulation program one Selectively inverted soft PICSY Singular value decomposition Tailored correlation spectroscopy Triple-resonance J cross-polarization Total correlation spectroscopy TOCSY-ROESY experiment TOCSY without NOESY... 

Figure 6.13. Elimination of parent H- C proton resonances through the BIRD-inversion recovery sequence. At the start of data collection no longitudinal proton magnetisation exists but this reappears during the acquisition period and subsequent recovery delay (RD) through spin relaxation. The BIRD element selectively inverts only those protons attached to carbon-12, which then continue to relax during the inversion recovery delay, r. With an appropriate choice of x, the magnetisation has no longitudinal component when the HMQC sequence starts, so does not contribute to the detected FID.

Figure 7.6. The proton-detected selective heteronuclear J-resolved spectrum of adenosine 73. The HI proton has been selectively inverted and the doublet splittings in f record its long-range couplings to C8 and C2 (reproduced with permission from reference [6]).

Select inverted bucket traps based on condensate flow rate, pressure differential, and safety factor. ... 

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