Primary surface

Initial U concentration. If uranium concentration has changed as a result of diagenetic reactions, one may, in principle detect this by comparison between uranium concentrations in modem corals and their fossil counterparts. Early work documenting and studying uranium concentrations in corals is extensive (e g., Barnes et al. 1956 Tatsumoto and Goldberg 1959 Veeh and Turekian 1968 Schroeder et al. 1970 Thompson and Livingston 1970 Gvirtzman et al 1973 Amiel et al. 1973 Swart 1980 Swart and Hubbard 1982 Cross and Cross 1983). This broad body of data shows that primary surface coral uranium concentrations lie between 1.5 and 4 ppm (see Fig. 1). Concentrations appear to be species dependent (Cross and Cross 1983). Furthermore, uranium concentrations vary within individual coral skeletons (Schroeder et al. 1970 Shen and Dunbar 1995 Min et al. 1995). 

Most major ore deposits that intersect the earth s surface have probably been identified. To satisfy the increasing demand for metals, buried deposits lacking primary surface expressions have become targets for exploration. Future discoveries of economic mineral deposits increasingly rely on the identification of subtle, secondary expressions of deeply buried metal bearing systems (Govett 1976 Kelly et al. 2006). 

The Langmuir-Hinshelwood reaction between adsorbed CO and O atoms is well established as the dominant reaction mechanism for conditions where CO is the primary surface species . This mechanism has been confirmed by numerous UHV studies of the coadsorption of the transient kinetic... 

This pentacoordinated surface intermediate undergoes rapid hydrogenolysis of the Sn-R bonds (Scheme 2.36). The primary surface complex [MsSnRs] is formed [121]. 

In an early version of this apparatus, the secondary surface is 2 cm away from the primary surface hence, sputtered neutrals, which may constitute the majority of the transferred particles, present a problem during materials transfer. Despite the pitfalls of this simple design, transfers of material have been made which show a dependence on secondary ion energy. For Ag sputtered on phenanthrol ine-Pt, a large [Ag+M]+ peak was seen for 300 eV Ag ions, while for 10 eV Ag ions the [Ag+M] + peak was much smaller. 

The next step in the experiment will be to incorporate mass analysis of material sputtered from the primary surface in order to reject neutrals and to be more selective in what is deposited on the secondary surface. It is hoped that catalytically useful materials, such as mass-selected small metal clusters, may eventually be deposited on surfaces. Furthermore, it may be possible to transfer reactive organic species (such as those in Table IV) to create new materials through control of the potential between the two surfaces. 

A promising aspect of RS for probing surface chemistry involves its ability to evaluate the molecular orientation of monolayer coverages via polarization measurements (146). The orientation of a surface active dye, Suminol Milling Brilliant Red BS, has been studied at a water-carbon tetrachloride interface (147). As the surface area per molecule was reduced the spectra showed a transition which was interpreted as a change from a mixture of orientations to one predominantly perpendicular with respect to the surface. A thorough theoretical analysis of the use of depolarization ratios for the prediction of primary surface orientations of adsorbed molecules has also been reported (148). Similar developments are occurring in IR spectrscopy and a determination of the molecular orientations in a series of polymers has been reported (149). 

McDonald C. Low-cost compact primary surface recuperator concept for microtur-bines. Appl Thermal Eng 2000 20 471-497. 

The characteristics of the primary surfaces and the derived surface for the solid-liquid equilibria and the solid-vapor equilibria are identical to those for the liquid-vapor equilibria with the exception that no critical phenomena have ever been observed in these two equilibria. Thus, a plane, tangent to the solid and liquid surfaces, may be rolled along these surfaces. The projections of the loci of the points of tangency are represented by the lines al and bs in Figure 5.5. If the points of tangency are connected by a straight line lying in the plane at any position of the plane, a ruled surface is derived... 

In summary, we refer to Figure 5.5, which may be considered as the projection of the entire equilibrium surface on the entropy-volume plane. All of the equilibrium states of the system when it exists in the single-phase fluid state lie in the area above the curves alevd. All of the equilibrium states of the system when it exists in the single-phase solid state lie in the area bounded by the lines bs and sc. These areas are the projections of the primary surfaces. The two-phase systems are represented by the shaded areas alsb, lev, and csvd. These areas are the projections of the derived surfaces for these states. Finally, the triangular area slv represents the projection of the tangent plane at the triple point, and represents all possible states of the system at the triple point. This area also is a projection of a derived surface. 

Primary surface information surface area, adsorption site concentration. 

Primary surface information electronic structure, surface structure. 

Primary surface information valence band structure, bonding. 

Primary surface information chemical environment, oxidation state. 

Primary surface information composition, oxidation state. 

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