Quasi-elastic electron scattering

Recently, a four-laboratory cooperative study has led to a comparison of the determination of particle size distribution by electron microscopy, quasi-elastic light scattering and wide angle light scattering (20). 

Among bile salts, sodium cholate (NaC) and sodium deoxycholate (NaDC) have been extensively studied by a variety of physical techniques. A few prominent techniques include nuclear magnetic resonance [68], electron spin resonance [69], small angle X-ray scattering [70], and quasi-elastic light scattering [71]. 

This review article is concerned with the structure, bonding, and dynamic processes of water molecules in crystalline solid hydrates. The most important experimental techniques in this field are structural analyses by both X-ray and neutron diffraction as well as infrared and Raman spectroscopic measurements. However, nuclear magnetic resonance, inelastic and quasi elastic neutron scattering, and certain less frequently used techniques, such as nuclear quadrupole resonance, electron paramagnetic resonance, and conductivity and permittivity measurements, are also relevant to solid hydrate research. 

Schematic models for the expanded structure of bile acid-phosphatidylcholine mixed micelles are shown in Fig. 2B. The original model was proposed by Small in 1967 (S36). In this model the mixed micelle consisted of a phospholipid bilayer disk surrounded on its perimeter by bile acid molecules, which were oriented with their hydrophilic surhices in contact with aqueous solvent and their hydrophobic sur ces interacting with the hydrocarbon chains of the phosphohpid molecules. This model has recently been revised, based on further studies of mixed micelles using quasi-elastic light scattering spectroscopy (M20). In a new model for the molecular structure of bile acid-phospholipid mixed micelles. Mazer et al. (M20) propose a mixed disk, in which bile acids are found not only on the perimeter of phospholipid bilayers, but also incorporated within their interior in high concentrations (Fig. 2B). The size of these mixed micelles was estimated to be as high as 200 to 400 A in radius in some solutions, and disk-shaped particles in this size range were observed by transmission electron microscopy (M20). Micellar aggregates similar in size and structure to those found in model bile solutions have been demonstrated in dog bile (M22).

In the particular case of a bimodal particle size distribution where the second size is very small, detection can be difficult This is illustrated by the data in Table 12.13, which shows that the bimodal characteristic was measured by transmission electron microscopy (TEM), capillary hydrodynamic fractionation (FlowSizer), and by SFFF, but not by quasi-elastic light scattering (NICOMP 270 or Brookhaven B 1-90). While QELS (or PCS) instruments are capable of... 

Radioactive tracers were utilized by Bueche (1962) to measure self diSusion coefficients for polymer systems above their glass-transition temperature, Tg. Price et al. (1978) described a novel approach that used scanning electron microscopy (SEM) and dispersive energy X-ray fluorescence analysis to measure the interdiffusion (D Kh cmVsec) of compatible polymer/polymer systems. Quasi-elastic light scattering (QELS) is an unusual technique due to its ability to measure both the mutual and self diffusion coefficients. Patterson et al. (1981) and Amis s. (1983) have demonstrated the apphcahon of this technique to polymeric gels. 

Spectroscopic methods for hydration of ions were reviewed for structural aspects and dynamic aspects of ionic hydration by Ohtaki and Radnai (150). They discussed X-ray diffraction, neutron diffraction, electron diffraction, small-angle X-ray (SAXS) and neutron-scattering (SANS), quasi-elastic neutron-scattering (QENS) methods, extended X-ray absorption fine structure (EXAFS), X-ray absorption near-edge structure (XANES) spectroscopies, nuclear magnetic resonance (NMR), Mdssbauer, infrared (IR), Raman, and Raleigh-Brillouin spectroscopies. The clay interlayer molecular modeling where clay surface is interfaced with aqueous solution also includes ions that are also solvated by interlayer water. 

The divergence of the central-peak in Pr3Tl at T was investigated in detail by quasi-elastic neutron scattering (Als-Nielsen et al. 1977). The interesting result is that the data can not be explained within the frame work of the Effective Interaction Models. However, the inclusion of the dynamics of the conduction electrons (see section 5.1.5) leads to the required results (Becker et al. 1977). This gives support to the model described in section 5.1.5. 

In this study we have investigated the structural and interaction parameters of ternary water/octane/CiaEs system by means of SAXS. Phase behavior of this system was studied by Kahlweit et al. [9]. This system shows interesting phase behavior (Fig. 1). One can study the structures of low-temperature microemulsion (LTM) phase, middle-temperature lamellar (MTL) phase and high-temperature microemulsion (HTM) phase by changing temperature only, provided that the sample contains approximately more than 12 wt% of surfactant at equal volume fraction of water and oil. Bodet et al. have clarified the structural evolution of this system by means of pulsed-field gradient spin-echo NMR, quasi-elastic light scattering and freeze-fracture transmission electron microscopy [10]. Local structure of the bilayer and monolayer of the same system was also studied by Strey et al. [11]. Recently, we have studied the mechanism of the phase transition [12]. 

Influence of Temporary Electron Trapping on Quasi-Elastic Scattering and Phonon Creation... 

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