Reflection cross section

We prepared aluminium oxide films by radio frequency (r.f) magnetron sputtering fi om an aluminium oxide target in a dedicated vacuum chamber. To study the growth and structure of these films deposited on silicon oxide and films of DIP we used X-ray reflectivity, cross-sectional transmission electron microscopy (TEM) and atomic force microscopy (AFM) in contact mode. For further details on the preparation of the aluminium oxide films we refer to Refs. [112, 113]. 

Figure 1. Total Internal Reflection. Cross section of the end of an optical fiber. Refractive index of the core is nj, and refractive index of either the cladding (hatched) or aqueous media is n2- Light reflecting at angles less than 0c under go total internal reflection.

The concept of the reflection cross section of thermal neutrons dp as a microscopic parameter for the characterization of the reflection property of substances has been introduced (Csikai and Buczko 1999). The relation between 77, dp, and the surface density of atoms is given by... 

Figure 4-61. Different measuring heads for different modes of reflectance (cross section), a) 45°/45° regular reflectance b) 30°/30° regular reflectance c) 0°/45° diffuse reflectance d) 30°/30° integral reflectance. BP black plastic WP white plastic FC fiber cable SP sample port.

In this paper, discontinuities in cylindrical specimens were studied by ultrasonic reflection tomography. The aim was threefold. First, to localize discontinuities from circular C-scan images. Second, to reconstruct quantitative cross-sectional images from circular B-scan profiles (i.e., reflection tomograms). Finally, to obtain three-dimensional information (i.e., discontinuity location, dimension and type) by stacking these reflection tomograms in multiple planes, in the third dimension. 

The lines of primary interest ia an xps spectmm ate those reflecting photoelectrons from cote electron energy levels of the surface atoms. These ate labeled ia Figure 8 for the Ag 3, 3p, and 3t7 electrons. The sensitivity of xps toward certain elements, and hence the surface sensitivity attainable for these elements, is dependent upon intrinsic properties of the photoelectron lines observed. The parameter governing the relative iatensities of these cote level peaks is the photoionization cross-section, (. This parameter describes the relative efficiency of the photoionization process for each cote electron as a function of element atomic number. Obviously, the photoionization efficiency is not the same for electrons from the same cote level of all elements. This difference results ia variable surface sensitivity for elements even though the same cote level electrons may be monitored. 

Laser stimulation of a silver surface results in a reflected signal over a million times stronger than that of other metals. Called laser-enhanced Raman spectroscopy, this procedure is useful in catalysis. The large neutron cross section of silver (see Fig. 2), makes this element useful as a thermal neutron flux monitor for reactor surveillance programs (see Nuclearreactors). 

Boron [7440-42-8] B, is unique in that it is the only nonmetal in Group 13 (IIIA) of the Periodic Table. Boron, at wt 10.81, at no. 5, has more similarity to carbon and siUcon than to the other elements in Group 13. There are two stable boron isotopes, B and B, which are naturally present at 19.10—20.31% and 79.69—80.90%, respectively. The range of the isotopic abundancies reflects a variabiUty in naturally occurring deposits such as high B ore from Turkey and low °B ore from California. Other boron isotopes, B, B, and B, have half-Hves of less than a second. The B isotope has a very high cross-section for absorption of thermal neutrons, 3.835 x 10 (3835 bams). This neutron absorption produces alpha particles. 

Fig. 5. A 90° polished cross section of a production white titania enamel, with the microstructure showing the interface between steel and direct-on enamel as observed by reflected light micrography at 3500 x magnification using Nomarski Interface Contrast (oil immersion). A is a steel substrate B, complex interface phases including an iron—nickel alloy C, iron titanate crystals D, glassy matrix E, anatase, Ti02, crystals and F, quart2 particle.

The next step is to consider tire cross-sections of the absorption of radiation by the diatomic halogen molecules in order to decide if the relative effects result from the efficiency of the radiation photon-molecule interactions. These are reflected in the dissociation cross-sections of tlrese interactions. 

It should be noted that low-loss spectra are basically connected to optical properties of materials. This is because for small scattering angles the energy-differential cross-section dfj/dF, in other words the intensity of the EEL spectrum measured, is directly proportional to Im -l/ (E,q) [2.171]. Here e = ei + iez is the complex dielectric function, E the energy loss, and q the momentum vector. Owing to the comparison to optics (jqj = 0) the above quoted proportionality is fulfilled if the spectrum has been recorded with a reasonably small collection aperture. When Im -l/ is gathered its real part can be determined, by the Kramers-Kronig transformation, and subsequently such optical quantities as refraction index, absorption coefficient, and reflectivity. 

The properties of mesophase pitch-based carbon fibers can vary significantly with fiber texture. Inspection of the cross-section of a circular mesophase fiber usually shows that the graphitic structure converges toward the center of the fiber. This radial texture develops when flow is fully developed during extrusion through the spinnerette. Endo [48] has shown that this texture of mesophase pitch-based carbon fibers is a direct reflection of their underlying molecular structure. 

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