Magnetic susceptibility volume

A new rapid mid-infrared spectroscopic method called diffuse reflectance infrared Fourier transform spectra (DRIFTS), coupled with chemometrics, has been developed by Janik, Merry, and Skjemstad (1998) and routinely applied to rapidly screen and compare crime scene samples (Figure 1.1). Added to these rapid methods and techniques are the use of rapid mass and volume magnetic susceptibility methods, which should also always be used before moving to the more costly methods (Figure 1.1). Mineral magnetic techniques are a relatively recent development (post-1971) and have now become a very powerful and widely used research tool to characterize natural materials in landscapes (e.g., Thompson and Oldfield 1986). 

If M is the magnetization (magnetic dipole moment per unit volume, analogous to the dielectric polarization P) induced by the field H, the volume magnetic susceptibility x is defined by the equation... 

In general, two different solvent effects on NMR spectra can be distinguished (a) shifts due to a difference in the bulk volume magnetic susceptibility x of the solute and the solvent (b) shifts arising from intermolecular interactions between solute and solvent molecules. Since the bulk susceptibility effect depends on the shape of the sample and, therefore, is not of chemical interest, some form of correction for it is applied. For two... 

Magnetic susceptibility gram magnetic susceptibility is obtained by dividing the volume magnetic susceptibility... 

Coaxial tubing is also used in the determination of volume magnetic susceptibility (xv)2° 23 by NMR spectroscopy. Recently, we found an easier and more accurate method of xv determination.23 The chemical shifts of the sample in the outer cell are observed on a superconducting solenoid spectrometer (500 MHz) (<5t) and an electromagnetic spectrometer (100MHz) ( S2) by referring to the external standard signal from the inner cell. The difference between the chemical shifts, 6] — S2, is described as follows ... 

Here a mean volume magnetic susceptibility has been introduced X = M/H... 

Molar magnetic susceptibility Volume magnetic susceptibility Ti Constant of spin-lattice or longitudinal relaxation... 

The volume magnetic susceptibility of a suspension of packed deoxygenated herytrocytes is given in figure 1 as a function of the inverse of temperature. As it can be seen a Curie-law behavior is exhibited and the best fit line of the figure can be written as... 

Volume magnetic susceptibility of packed human red cells suspensions at room temperature. 

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