Nuclear magnetic resonance continuous wave

For the pressure studies, two phase" compact ion behavior is observed with an inflection point between 7 and 11 atms. For the aqueous solution studies, the hydraulic permeability K and the g-ratio are hardly effected by solute type (within experimental error). The solute diffusive permeability however, varies with solute type in good qualitative agreement with free energy parameters, infrared overtone shifts, and spin echo and continuous wave nuclear magnetic resonance spectroscopy results from the literature. 

NMR nuclear magnetic resonance, pulsed or continuous-wave (CW). 

The nuclear magnetic resonance phenomenon was first observed through a continuous wave experiment [2-6]. Resonance between the two Mj levels of an / = V2 nucleus (without loss of generality) in a magnetic field Bo can be achieved by applying a magnetic field rotating with a frequency (see Eqs. (1.12) and (1.16)) such that... 

Another method (ASTM D-4808) covers the determination of the hydrogen content of petroleum products, including vacuum residua, using a continuous-wave, low-resolution nuclear magnetic resonance spectrometer. Again, sample solubility is a criterion that will not apply to coal but will apply to coal extracts. More recent work has shown that proton magnetic resonance can be applied to solid samples and has opened a new era in coal analysis by this technique (de la Rosa et al., 1993 Jurkiewicz et al 1993). 

The first experimental observation of electron spin resonance was made on an iron compound by Zavoisky in Russia in 1944. A year later Purcell and Bloch and their collaborators observed independently nuclear magnetic resonance in condensed matter. While the celebrated Purcell and Bloch discoveries have sparked an explosive wave of research on nuclear magnetic resonance throughout the world, little activity on electron spin resonance followed immediately after the first success. In fact, even Zavoisky did not continue working in the field of ESR, and the development of the technique was almost exclusively left to the physicists in the decade after the war. Indeed, the potential diversity of applications of ESR to chemistry could hardly have been foreseen in the earlier days. 

CW = continuous-wave CW-NQR = continuous wave NQR DFT = density fiuictional theory EFG = electric field gradient IR = infrared NMR = nuclear magnetic resonance NQR = nuclear quadmpole resonance OSSE = octahedral site stabilization energy PAC = perturbed angular correlation pulse-FT = pulse-fourier transform TMED = tetramethylethylenediamine. 

A2. Alderman, D. W., Improvement of signal-to-noise ratio in continuous-wave nuclear magnetic resonance at liquid-helium temperature by using a metal oxide semiconductor field-effect-transistor radio-frequency amplifier. Rev. Set. Instrum. 41, 192-197 (1970). 

Cr(V)) The polarisation of the protons is measured by continuous-wave nuclear magnetic resonance (NMR), calibrated by measurments of the NMR signal in thermal equilibrium with the helium bath around 1 K. 

R317 L. A. Colnago, R. B. V. Azeredo, A. Marchi Netto, F. D. Andrade and T. Venancio, Rapid Analyses of Oil and Fat Content in Agri-Food Products Using Continuous Wave Free Precession Time Domain Nuclear Magnetic Resonance , Magn. Reson. Chem., 2011, 49(S1), SI 13. 

International Standard Organization ISO 5511-1992. Oilseeds—Determination of Oil Content—Method using Continuous-Wave Low-Resolution Nuclear Magnetic Resonance Spectrometry (Rapid method). Re-approved in 1997. 

The advances in the field of Fourier transform infrared (FT-IR) spectrometry in the past 20 years have been quite remarkable. FT-IR spectrometers are installed in just about every analytical chemistry laboratory in the developed world. Actually, we sometimes wonder why so many people still refer to these instruments as FT-IR spectrometers, or more colloquially simply as FTIRs, rather than simply as infrared spectrometers, since almost all mid-infrared spectra are measured with these instruments. We note that scientists who use nuclear magnetic resonance, the other technique that has been revolutionized by the introduction of Fourier transform techniques, no longer talk about FT-NMR, as continuous-wave instruments (e.g., grating monochromators) are a distant memory. Nonetheless, practitioners of infrared spectrometry seem to want to recall the era of grating monochromators, even though the vast majority has never seen one ... 

In contrast to nuclear magnetic resonance (NMR) methods, NQR can operate without a strong external DC magnetic field. This technique is known as pure NQR , or direct NQR detection, and has many advantages for some applications, such as identification of specific compounds and remote NQR. In turn, direct NQR detection techniques can be subdivided into two main areas oscillator-detector methods [continuous wave (CW) and superregenera-tive techniques] and pulsed methods. At present the pulse method is the most widely used direct NQR method. The use of various multipulse sequences permits a considerable increase in the sensitivity, and a decrease in the duration of the experiment. 

Nuclear Magnetic Resonance Spectrometer —A low-resolution continuous-wave instrument capable of measuring a nuclear magnetic resonance of hydrogen atoms, and fitted with ... 

A test specimen is compared in a continuous wave, low-resolution nuclear magnetic resonance (NMR) spectrometer with a reference standard sample. The spectrometer... 

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