نتایج جستجو برای: nuclear magnetic resonancenmr
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Hole burning, which is attributed to optical pumping of nuclear-quadrupole levels, has been observed in the stoichiometric rare-earth compound, EuP5O14 . The long lifetime of these holes (-60 min) implies slow nuclear-spin flip-flop rates. The small magnetic moment of Eu3+ has prevented conventional magnetic-resonance measurements on Eu3+ compounds, but hole burning provides a sensitive method ...
iron overload is a clinical problem which can be prevented by using iron chelating agents. an alternative method of relieving iron overload is to reduce iron absorption from the intestine by administering specific iron chelating agents, which can bind iron to form nonabsorbable complexes. based on this strategy, a series of polymeric ligands containing the chelating moiety 3-hydroxypyridin-4-on...
Professor Jonathan Parr By submitting this essay, I attest that it is my own work, completed in accordance with University regulations.—Andrew Yang An Introduction to Nuclear Magnetic Resonance Spectroscopy by Andrew Yang Nuclear Magnetic Resonance Spectroscopy, or NMR Spectroscopy, is a powerful nondestructive research technique that uses the magnetic properties of nuclei to investigate the co...
SCOPE This review focuses on developments and applications in the field of nuclear magnetic resonance of solids appearing in the literature between October 1999 and October 2001. The review emphasizes uses of solid-state NMR spectroscopy to answer questions about problems in certain areas of chemistry and materials science. As time passes, the use of solid-state techniques to address problems i...
One of the most important reactions of the URCA that lead to the cooling of a neutron star, is neutron beta-decay ( ). In this research, the energy spectra and wave functions of massive fermions taking into account the Anomalous Magnetic Moment (AMM) in the presence of a strong changed magnetic field are calculated. For this purpose, the Dirac-Pauli equation for charged and neutral fermions is ...
Complexes of histidine with Co( 11) in aqueous solution have been examined by proton magnetic resonance spectroscopy. Coordinate interaction of histidine with paramagnetic Co( 11) produces large contact interaction shifts in the histidine proton resonance spectra. Four histidine-Co( 11) complexes have been distinguished : a weak 1: 1 histidine-Co(I1) complex a t low pH ( < 4 ) in which only the...
In 2001, Mauri and Pickard introduced the gauge including projected augmented wave (GIPAW) method that enabled for the first time the calculation of all-electron NMR parameters in solids, i.e. accounting for periodic boundary conditions. The GIPAW method roots in the plane wave pseudopotential formalism of the density functional theory (DFT), and avoids the use of the cluster approximation. Thi...
The drive to improve the sensitivity of nuclear magnetic resonance (NMR) to smaller and smaller sample volumes has led to the development of a variety of techniques distinct from conventional inductive detection. In this chapter, we focus on the technique of force-detected NMR as one of the most successful in yielding sensitivity improvements. We review the rationale for the technique, its basi...
Techniques for studying molecular structure, such as x-ray diffraction and nuclear magnetic resonance (NMR), often require the use of single crystals' or oriented samples. ' NMR, for example, is sensitive to interatomic distances and angles through spectral splittings caused by internucl. ear dipol. e-dipole couplings in high magnetic field. Where only polycrystalline powders or amorphous mater...
THEORY: The physics behind NMR/MRI signal production lies in the physics of spin. This section will cover enough aspects of spin to understand the generation of NMR signals. Although this initial spin discussion is inherently quantum mechanical in nature, we will later need to employ some simple principles from thermodynamics and classical dynamics to further describe the art of NMR. These topi...
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