Coupling optimization

Another approach is to intentionally select a very small coupling optimization such that integer multiples of that coupling will be in phase and read out at the end of the experiment with maximal intensity. The author (GEM) and a co-worker reported this approach using a 1.75 Hz optimization in the acquisition of proton double quantum coherence of strychnine (1) many years ago with some degree of success. 

Kim et al. (2009,2011) proposed a structural optimization considering processing parameters in the case of compression molding process. While the conventional structural design and analysis has been based on the assumption of isotropic properties in the final part, they integrated the structural analysis with the simulation of fiber orientation and separation into the optimization scheme. This structure-process coupled optimization is useful to further improve the product quality compared to the conventional separate structural design and process optimization procedures. 

Triantafyllou, C., and Smith, R., The Design and Optimization of Fully Thermally Coupled Distillation Columns, Trans. IChemE, Part A, 70 118, 1992. 

For special applications such as air coupled testing a special programmable transmitter board was developed. This transmitter generates rectangular and burst signals, which increase the acoustical power in an optimized frequency range, and provides a superior signal-to-noise ratio. 

The key for optimally extracting infonnation from these higher order Raman experiments is to use two time dimensions. This is completely analogous to standard two-dimensional NMR [136] or two-dimensional 4WM echoes. As in NMR, tire extra dimension gives infonnation on coherence transfer and the coupling between Raman modes (as opposed to spins in NMR). 

NOE-difFerence spectroscopy is particularly valuable for distinguishing stereoisomers, for it relies solely on intemuclear distances, and thus avoids any problems of ambiguity or absence associated with couplings. With smallish molecules, it is best carried out in the above 1D maimer, because 2 s are necessary for tire transmission of the NOE. The transmission process becomes more efficient with large molecules and is almost optimal for proteins. However, problems can occur with molecules of intemiediate size [3f]. A 2D version of the NOE-difference experiment exists, called NOESY. 

Microwaves from the waveguide are coupled into the resonator by means of a small coupling hole in the cavity wall, called the iris. An adjustable dielectric screw (usually machined from Teflon) with a metal tip adjacent to the iris pennits optimal impedance matching of the cavity to the waveguide for a variety of samples with different dielectric properties. With an appropriate iris setting the energy transmission into the cavity is a maximum and simultaneously reflections are minimized. The optimal adjustment of the iris screw depends on the nature of the sample and is found empirically. 

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