Small-angle diffusion

Presence of small-angle diffusion dispersion speaks about the presence of submicrovoids (SMV) in the fibre. Rearranging SADD according to the data of Figure 1.5 in coordinates Ig I from (Figure 1.6.) by the procedure described in the work [131] there may be defined the... 

There again, one observes a small angle diffuse ring which arises from lateral interferences among ribbons. The position of this diffuse ring is inversely proportional to the average distance between ribbons which varies with the concentration. At low concentrations, this distance follows... 

Wang W, Murthy NS, Grubb DT. Central small-angle diffuse scattering from fibers is made of two components. J Polym Sci B 2012 50 797-804. 

Other techniques such as X-ray diffusion or small angle neutron diffusion are also used in attempts to describe the size and form of asphaltenes in crude oil. It is generally believed that asphaltenes have the approximate form of very flat ellipsoids whose thicknesses are on the order of one nanometer and diameters of several dozen nanometers. 

FIG. 33 X-Ray Diffraction Patterns of Ammonium Dodecane 1-Sulfonate. 2-D (a) and 3-D plots (b) of oriented samples. Both pictures show the presence of a nonordered smectic phase, since the diffuse, weak, wide-angle diffraction indicates only an average distance between the molecules and the sharp, intense small angle reflections a very well defined layer distance. The reflections are perpendicular to each other, so the structure should correspond to an orthogonal smectic A type. The pictures were obtained using an x-1000 area detector from Siemens. 

For small angles (QRe 1), the second and third terms in (24) are negligibly small and S(Q,t) describes the center-of-mass diffusion of the coil... 

Sliding diffusion Small angle X-ray scattering (SAXS) Topology... 

The simple water charmel models can explain the ionomer peak and the small-angle upturn in the scattering data of fhe unoriented samples as well as of the oriented films. Interestingly, the helical structure of backbone segments is responsible for fhe sfabilify of fhe long cylindrical charmels. The self-diffusion behavior of wafer and protons in Nation is well described by the water channel model. The existence of parallel wide channels af high wafer uptake favors large hydrodynamic confributions to electro-osmotic water transport and hydraulic permeation. 

Fig. 6.20 Small angle scattering intensity (triangles log I) and effective diffusion DgfKQ) obtained from g=A carbosiloxane dendrimers with perfluorinated end groups in perfluo-rohexane. The dashed line is a fit to the prediction of a model for shape fluctuations of micro-emulsion droplets, the resulting bending modulus was 0.5 k T. (Reprinted with permission from [308]. Copyright 2003 Springer Berlin Heidelberg New York)...

When layers of certain block copolymers of ethylene oxide and butylene oxide are contacted with water, there is an initial period when the position of the interface is proportional to tm, where m < 0.5 [32]. That is, initial swelling is not controlled by diffusion but instead by hydration and rearrangement of the long molecules to form the various phases. In the case of (EO)i6(BO)22 small-angle X-ray scattering did detect evidence of both reverse hexagonal and lamellar phases during this initial period, but it was not clear whether all the swollen block copolymer layer consisted of these phases or how the... 

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