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Polarization can be used to filter out unwanted signals, such as jamming. If a jammer and receiver do not have the same polarization, the jamming signal will incur a loss that reduces its effectiveness. The four basic polarizations are linear horizontal, linear vertical, right-hand circular, and left-hand circular.
Cross-polarization (CP), originally published as proton-enhanced nuclear induction spectroscopy (PENIS) [1] [2] is a solid-state nuclear magnetic resonance (ssNMR) technique to transfer nuclear magnetization from different types of nuclei via heteronuclear dipolar interactions.
Insensitive nuclei enhancement by polarization transfer (INEPT) is a signal enhancement method used in NMR spectroscopy. It involves the transfer of nuclear spin polarization from spins with large Boltzmann population differences to nuclear spins of interest with lower Boltzmann population differences. [ 1 ]
Nuclear Overhauser Effect Spectroscopy (NOESY) is a 2D NMR spectroscopic method used to identify nuclear spins undergoing cross-relaxation and to measure their cross-relaxation rates. Since 1 H dipole-dipole couplings provide the primary means of cross-relaxation for organic molecules in solution, spins undergoing cross-relaxation are those ...
The term is mainly used in coordination chemistry. The template effects emphasizes the pre-organization provided by the coordination sphere, although the coordination modifies the electronic properties (acidity, electrophilicity, etc.) of ligands. [1] An early example is the dialkylation of a nickel dithiolate: [2]
Magic-angle spinning: The sample (blue) is rotating with high frequency inside the main magnetic field (B 0). The axis of rotation is tilted by the magic angle θ m with respect to the direction of B 0. In solid-state NMR spectroscopy, magic-angle spinning (MAS) is a technique routinely used to produce better resolution NMR spectra.
The jamming phase diagram relates the jamming transition to inverse density, stress and temperature. [2] The density at which systems jam is determined by many factors, including the shape of their components, the deformability of the particles, frictional interparticle forces, and the degree of dispersity of the system. The overall shape of ...
One consequence of this natural polarization of molecules is that 1,3- and 1,5- heteroatom substituted carbon skeletons are extremely easy to synthesize (Aldol reaction, Claisen condensation, Michael reaction, Claisen rearrangement, Diels-Alder reaction), whereas 1,2-, 1,4-, and 1,6- heteroatom substitution patterns are more difficult to access ...