X-ray scattering angle

Fig. 6. A plot of the characteristic peak positions (dashed line) in a solution X-ray scattering experiment (Q = 4w sin d/l, where d is half the X-ray scattering angle and 1 is 1.38 A, the wavelength of the X-rays) used to monitor the change in Na V particle size as a function of pH. The spherically averaged particle radius is shown by the solid line. The plot illustrates the highly cooperative pH dependence of the transition (Canady et al, 2001).

The x-rays of oriented smectic polymers are usually characterized by the presence of a series of distinct layered reflections with small x-ray scattering angles (Fig, 6.10). This arrangement of the side branches is predominantly perpendicular with respect to the plane of the smectic layer in which the main chains of the macromolecules lie. 

However, a shift in various peaks present in the XRD diflractograms (refer Fig. 6.35) from lower to higher X-ray scattering angle (i.e., inversely proportional to d-spacing of a mineral) is an indication of a novel mineralogical phase transition, which has not been reported earlier from conventional fusion followed by hydrothermal method. 

The structure of microemulsions have been studied by a variety of experimental means. Scattering experiments yield the droplet size or persistence length (3-6 nm) for nonspherical phases. Small-angle neutron scattering (SANS) [123] and x-ray scattering [124] experiments are appropriate however, the isotopic substitution of D2O for H2O... 

Brumberger H (ed) 1967 Small-Angle X-ray Scattering (New York Gordon and Breach)... 

Cakmak M, Teitge A, Zachman FI G and White J L 1993 On-line small-angle and wide-angle x-ray scattering studies on melt-spinning poly(vinylidene fluoride) tape using synchrotron radiation J. Polym. Sc/. 31 371- 81... 

Figure C2.17.12. Exciton energy shift witli particle size. The lowest exciton energy is measured by optical absorjDtion for a number of different CdSe nanocrystal samples, and plotted against tire mean nanocrystal radius. The mean particle radii have been detennined using eitlier small-angle x-ray scattering (open circles) or TEM (squares). The solid curve is tire predicted exciton energy from tire Bms fonnula.

Mattoussi H efa/1996 Characterization of CdSe nanocrystalline dispersions by small angle x-ray scattering J. Chem. Phys. 105 9890... 

O. Kiathy, in O. Glatter, O. Kiathy, eds., Small-Angle X-Ray Scattering, Academic Press, Inc., New York, 1982. 

Characterization. When siHca gel is used as an adsorbent, the pore stmcture determines the gel adsorption capacity. Pores are characterized by specific surface area, specific pore volume (total volume of pores per gram of solid), average pore diameter, pore size distribution, and the degree to which entrance to larger pores is restricted by smaller pores. These parameters are derived from measuring vapor adsorption isotherms, mercury intmsion, low angle x-ray scattering, electron microscopy, gas permeabiHty, ion or molecule exclusion, or the volume of imbibed Hquid (1). 

Copolymers of vinyUdene chloride and methyl acrylate have been studied by x-ray techniques (75). For example, the long period (lamellar thickness) for an 8.5 wt % methyl acrylate copolymer was found to be 9.2 nm by smaH-angle x-ray scattering. The unit cell is monoclinic, with a = 0.686 and c = 1.247 nm by wide-angle x-ray scattering. 

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

Cazorla-Amords, D., dc Lecea, C. S. M., Alcaniz-Monge, J., Gardner, M., North, A. and Dore, J., Characterization of activated carbon fibers by small-angle x-ray scattering. Carbon, 1998, 36(3), 309 312. 

Section 2 of this chapter describes the characterization of carbonaceous materials by powder X-ray diffraction, small-angle-X-ray scattering (SAXS), measurements of surface area, and by the carbon-hydrogen-nitrogen (CHN) test, a chemical analysis of composition. In this section, we also describe the electrochemical methods used to study carbonaceous materials. 

There are many ways to eharaeterize the strueture and properties of carbonaceous materials. Among these methods, powder X-ray diffraetion, small angle X-ray scattering, the BET surfaee area measurement, and the CHN test are most useful and are deseribed briefly here. To study lithium insertion in carbonaeeous materials, the eleetroehemieal lithium/earbon eoin eell is the most eonvenient test vehicle. 

Small-angle X-ray scattering (SAXS) [19] has been widely used to investigate the inhomogeneous electron density in materials [20]. In carbonaceous materials, porosity is commonly encountered. The pores form and provide escape routes for gases produced during the pyrolysis process. 

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