Free induction decay , nuclear magnetic resonance

Nuclear Magnetic Resonance (NMR) Spectroscopy. Longitudinal and transverse relaxation times (Ti and T2) of 1H and 23Na in the water-polyelectrolytes systems were measured using a Nicolet FT-NMR, model NT-200WB. T2 was measured by the Meiboom-Gill variant of the Carr-Purcell method (5). However, in the case of very rapid relaxation, the free induction decay (FID) method was applied. The sample temperature was changed from 30 to —70°C with the assistance of the 1180 system. The accuracy of the temperature control was 0.5°C. 

Abbreviations BCC. body centered cubic DOS. density of states ESR. electron spin resonance HX.AI S, extended X-ray absorption fine structure F CC. face centered cubic (a crystal structure). FID, free induction decay FT, Fourier transform FWHM, full width at half maximum HCP, hexagonal close packed HOMO, highest occupied molecular orbital IR, Infrared or infrared spectroscopy LDOS, local density of states LUMO, lowest unoccupied molecular orbital MAS. magic angle spinning NMR. nuclear magnetic resonance PVP. poly(vinyl pyrrolidone) RF. Radiofrequency RT, room temperature SEDOR, spin echo double resonance Sf, sedor fraction SMSI, strong metal-support interaction TEM. transmission electron microscopy TOSS, total suppression of sidebands. 

Abbreviations NMR, nuclear magnetic resonance 2D-NMR, two-dimensional NMR HOHAHA, 2D-NMR homonuclear Hartman-Hahn spectroscopy NOE, nuclear Overhauser effect NOESY, 2D-NMR nuclear Overhauser effect spectroscopy rf, radio frequency FID, free induction decay CD, circular dichroism PF4, platelet factor-4 IL-8, interleukin-8 Gro-a, growth-related protein a. 

Fig. 2.3. Outline of a conventional one-dimensional nuclear magnetic resonance experiment, (a) A sample in a nuclear magnetic resonance tube (b) a magnet into which the sample is placed (c) the outline of a simple experiment (d) the free induction decay (FID), which is Fourier-transformed to a spectrum (e).

The modulation of the spin-echo envelope can be used to obtain information about the coupling constant J The spin-echo envelope is also influenced if chemical exchange between the two nuclei occurs . Returning now to our main objective, i.e. the application of Fourier methods in nuclear magnetic resonance, we realize that the pulse methods lead to a decaying free-induction signal or a... 

A nuclear magnetic resonance line is usually found to have one of two ideal lineshapes - Gaussian, or more often, Lorentzian. A Gaussian line is found when there is a random distribution of static fields within the sample. A Lorentzian line by contrast arises because the spin lifetime follows a first-order decay law. Weighting functions can be applied to a free-induction decay to generate... 

Tiwari PN and Gambhir PN (1995) Seed oil determination without weighing and drying the seeds by combined free induction decay and spin-echo nuclear magnetic resonance signals. Journal of the American Oil Chemists Society 72 1017-1020. 

List of Abbreviations NMR, nuclear magnetic resonance O.D.260> optical density at 260 nm at 25 °C NOESY, nuclear Overhauser effect spectroscopy DQF-COSY, double quantum filtered correlation spectroscopy KP, potassium phosphate Tm, UV-melting point ER, endoplasmic reticulum PAGE, polyacrylamide gel electrophoresis TSP, trisilylpropionic acid sodium salt fid, free induction decay ffh, fifty-four-homologue j57iAf, methionine-rich domain of fifty-four-homologue. 

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