Oxygen atoms concentration profile

The second is concerned with the need to have a complete and sensible chemical mechanism, valid over a wide range of temperature. Even a relatively simple combustion system will involve dozens of reactions, so that a well established reaction rate data base is essential. It is equivalently essential that the results be verified by comparison with detailed experimental data--such as that provided by laser probes. For example, in a study of the ozone decomposition flame (20). it was found that certain alternative but wrong choices of key input parameters were not discernible if flame speed were used as the sole predicted result for verification however, these choices did produce considerable differences in the profiles of the transient oxygen atom concentration and the temperature. 

Kinetic curves on the change of ozone and oxygen atom concentrations are presented in Figure 3.5, while Figmes 3.6 and Figures 3.7 illustrate the calculation data for the time profiles of contributions of individual steps in relative units for the 1 and h functionals. 

FIG. 5 Local concentration profiles around a hydroxyl group in poly(vinyl alcohol) of heavy atoms in a (1 1) water/ethanol mixture A = OW water oxygen, A = OE ethanol oxygen, A = CE ethanol carbon. The local atomic fractions are defined as = a( )/ ZIb where a( ) is average number of atoms... 

In principle, one can take the interpretation further and calculate what oxygen concentration profile fits the measurements of the O/Ag ratio best. In fact, Baschenko et al. [39] did this and concluded that the subsurface oxygen resides mainly in the third and fourth atomic layer below the surface. Although the result appears plausible, it should be noted that such calculations are only permitted when the surface satisfies the requirements of lateral homogeneity and absence of roughness discussed above. As the O/Ag experiments were done with polycrystalline foils, one might wonder whether too detailed an analysis is warranted. Anyhow, the work forms a nice illustration of what angle-dependent XPS can achieve on catalytically relevant adsorbate systems. 

Depth profiles are usually presented as atomic concentrations versus sputter time, assuming we know the rate at which the sample sputters. A typical depth profile is shown in Figure 25. It is interesting to see that at the surface there is carbon, silicon dioxide and some molybdenum. As soon as the surface layer is sputtered off (300 A), the oxygen and carbon impurities drop to constant and small values. For this CVD film, the molybdenum silicide came out to be very silicon rich. We can also see that the stoichiometry of the silicide changed with position (depth) in the film. 

The formation of a rare earth metal oxide on the metal surface, impedes the cathodic reduction of oxygen and thus cathodic inhibition is achieved by the addition of a rare earth metal salt to a system. The surface atom concentration ratio, [Ce/Ce + M], where M is Fe, Al or Zn, is a function of cerium oxide film thickness determined by AES depth profiles as shown in Fig. 12.2. 

Fig. 26. (a) Translational temperature profiles along the 36° line of sight as a function of altitude, (b) Atomic oxygen concentration profiles along the 36° line of sight as a function of altitude. 

Fig. 1(a) shows concentration profiles of the components in the as-deposited and anodized film fabricated by magnetron sputtering of the composed target with the 25 % Ti inset area. The average content of Ti atoms in the as-deposited film was 27 %. They were uniformly distributed over the film thickness. Oxygen on top of the film relates to the native oxide. Similar results have been obtained for alloy films with another content of Ti. The difference between percentage of the Ti inset area and concentration of Ti atoms in deposited films was less than 10 %. 

The evaluation of structural properties such as orientation angles and layer thicknesses requires an appropriate definition of the water surface. In Figure 23.3 the average concentration profiles in the z-direction for water oxygen atoms, and the C , and... 

Before discussing these aspects we have to clarify the state of BP on the surface of the positive electrode material. We measured the depth profile of thecobalt positive electrode after 200 cycles by Auger electron spectroscopy (AES), as shown in Fig. 19.18. Thickness of the electroconductive membrane (ECM) film is estimated by the AES depth profiles atomic concentration of cobalt and oxygen. It reaches 90% with and without BP addition as shown in Fig. 19.18. The observed ECM film thicknesses are as follow in the basic electrolyte, the ECM film thickness was 45 A in the functional electrolyte containing 1% of BP, the ECM film thickness was 68 A in the functional electrolyte having 2% of BP, the ECM film thickness was 214 A. These results clearly show that the ECM film thickness on the positive electrode increased with the amount of BP. Based on these results, the cycle life of the basic electrolyte cell should be better, but the cells with the functional electrolyte containing the small amount of BP (the film thickness of 68 A) afford the best results. 

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