X-ray scattering patterns

Fig. 4. SmaH-angle x-ray scattering pattern from PVC plasticized with 20 parts per hundred resin of dioctyl phthalate (18).

Complementary information about the structure of the smectic phases is contained in the X-ray scattering patterns, as in studies of real mesogens. The intermolecular scattering patterns calculated (see Sect. 3) for GB(4,4, 20,0, 1,1)... 

Fig. 16. Time-resolved small-angle X-ray scattering patterns from polyethylene sheet recorded during stretch (12 mm/min, 32% stretch/min) in the horizontal direction. An exposure time for each pattern was 1 s. Intervals between exposures were 70 s. An X-ray wavelength was 0.155 nm...

Fig. 18. Time-resolved small-angle X-ray scattering patterns from polypropylene sheet under quick stretch in the horizontal direction. A speed of stretch was 233 mm/min (367 % stietch/min). An exposure time for each pattern was 0.1 s. Intervals between exposures were 0.2 s. An X-ray wavelength was 0.155 nm. A slight deformation of the symmetric SAXS pattern was already observed in the second patterns, suggesting some degree of orientation was brought about in quite an early stage. The SAXS patterns changed abruptly and drastically in the sixth pattern just when the sample began to yield (when the tension began to decrease).

The chemistry of the iron core is most interesting, in the light of the experiments mentioned above with respect to the hydrolytic polymers of Fe (III). The molecular structure of the iron core obtained from crystalline ferritin by treatment with concentrated sodium hydroxide has recently been investigated using low angle X-ray scattering patterns (44). These authors have proposed a structure quite similar to that of Green rust II ... 

Fig. 4.11 Small-angle X-ray scattering patterns from a face-centred cubic phase formed by a PEO127PPO48PEO127 (F108) Pluronic solution (35 wt% in water) at 30 °C during oscillatory shear at 10rad s 1 with a strain amplitude of 40% (Diat et al. 1996). The patterns correspond to (a) the (q qt) plane and (b) the (<7v,4V) plane. In (c) the pattern was recorded in the (qv,qt) plane but with the beam incident close to the outer rotor. It corresponds to one of the FCC twins giving the diffraction pattern in Fig. 4.12(b).

Fig. 4.17 Small-angle X-ray scattering patterns for 38wt% aqueous solutions of PE04oPB010 (a) BCC phase observed between 5 and 50°C (b) FCC structure between 50 and 75 °C (c) hexagonally-packed cylinder phase above 75 °C (Pople et al. 1997).

It is natural to ask whether the least-squares fits of (8) to the scattering curves for these 15 coals are merely exercises in curve fitting or whether the fact that quite good fits can be obtained, in many cases over the whole scattering curve at which data were recorded, means that the pore structure used in developing (8) really has some connection with the pore structure in the coals. This point is especially important because in principle, more than one sample can produce the same small-angle x-ray scattering pattern. 

Small-angle X-ray scattering patterns exhibit a weak single diffraction peak at ( =0.68 and 0.66nm" for SBAla and SBAlb respectively, characteristic of the wormlike stracture (Fig. 1) with a regular pore-pore distance [15], The corresponding d value was calculated to be 9.2 and 9.5 mn respectively. 

Fig. 45. Small-angle x-ray scattering pattern of oriented polyethylene (LDPE Ltipolen 1840 D) during four temperature cycles as recorded by a linear position sensitive detector. The detector was oriented parallel to the meridian of the small angle pattern...

Fig. 52. Selected wide angle X-ray scattering patterns during heating of polypropylene indicating the p- -transition (a) and the melting (b)...

Figure 16. Time-resolved SR X-ray scattering patterns of SLS (unit nm). At left is the temperature change with time.

The use of such small beams allows X-ray scattering patterns on single polymeric fibres with diameters down to a few microns to be collected in a few seconds. Thus scanning experiments across a fibre become feasible. It also allows study of individual spherulites or deformations near the edge of crack tips. Below are examples of work carried out on ID 13 at the ESRF. 

Interpretation of the WAXS patterns of native starch is often difficult because of the low crystallinity, small size, defects and the multiple orientations of the amylopectin crystallites (Waigh et al, 1997). Two main types of X-ray scattering patterns have been commonly observed (A and B). Potato starch has been shown to crystallize in a hexagonal unit cell in which the amylopectin molecules twist in a double helix (the B structure) (Lin Jana Shen, 1993). Between adjacent helices a channel is formed in which 36 water molecules can be located within the crystal unit cell. By means of heat treatment this structure can be transformed into a more compact monoclinic unit cell (the A structure) (Shogren, 1992). Amylose (the linear and minor component of starch) can be crystallized from solution in the A and B structures (Buledn etal, 1984), yielding X-ray diffraction patterns similar to those of amylopectin but with higher orientation. 

Figure 20. Calculated X-ray scattering patterns for various types and sizes of Pt nanocrystallites. Top left 3.5 nm (a) sphalerite (b) wurtzite (c) wurtzite with one stacking fault (d) experimental powder spectmm with ca. 3.5.nm avg. crystallites. Top right Experimental powder diffraction pattern of ca. 8.0 nm crystallites (dotted line) compared to (a) spherical and (b) prolate particles (solid line) Center (a) progression of habits of cuboctahedral shapes of nanocrystals, (b) change in shape as 111 faces increase and 100 decrease, (c) decahedron and icosahedron multiply twiimed forms. Bottom left to right three successive sizes of cuboctahedral nanociystallites three successive sizes of decahedral nanociystallites three successive sizes of icosahedral nanocrystallites. From Zanchet et al. (2000), used with permission of Wiley-VCH.

Figure 17. Small-angle X-ray scattering pattern of rod-coil molecule 13c. (Reprinted with permission from ref 67. Copyright 2000 American Chemical Society).

Figure 8.23 Low-angle X-ray scattering pattern of FDU-1 (indexed with Fm3m) and its TEM image. Reproduced with permission from [138], Copyright (2003) American Chemical Society...

Figure 3. Small-angle x-ray scattering patterns of polytrioxane. (A) Sample PTOX-80 by radiation initiation (B) Sample PTOX-20-1P by plasma initiation and (C) Sample PTOX-40P by plasma initiation.

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