Atomic fraction 18

An estimate of AR ia alloys can be made usiug the empirical expression (12) of equation 10 where the average alloy reduced energy, is defined by equation 11, where C (i = 1, 2,... , n) is the elemental atomic fraction of the /th element, and is the elemental reduced energy defined iu equation 3. Using this formulation, the projected range straggling iu compounds can be calculated to within 20%. 

Prove this result to yourself. Notice that, for the first time in these notes, we have not given a parallel result for atomic (or mol) fraction. You cannot have an atom fraction of a phase because a phase (as distinct from a pure element, or a chemical compound of a speeifie composition) does not have an atomic weight. Its composition can vary within the limits given by the phase diagram. 

The easiest way to obtain the concentration m of the isotope A is to use a reference sample ( standard ), that contains the isotope A with a known atomic fraction/ for comparison. Knowing the NRA yield of the standard Yst and its stopping cross-section gt, the atomic fraction m in the sample can easily be evaluated from the yield Ya of the sample for the same projectile energy, taking the different stopping cross-sections into account ... 

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... 

Calculations. The atoms of incorporated lsO is calculated from mass spectral data. When the ratio of the peak heights at mass-to-charge ratio (m/e) 44, 46 and 48 for CO2 is X-.Y-.Z, assuming that the height of each peak is strictly proportional to the number of CO2 molecules, the atom fraction of l80 in CO2, C, is given by ... 

VARIATION OF FIRST-ORDER RATE COEFFICIENTS WITH ATOM FRACTION OF... 

As we have already stated, Ny so that the atomic fraction of vacancies is ... 

Figure 1.70. Ag content (atomic fraction of Ag) of electrum from the Te-type and Se-type deposits (Shikazono et al., 1990). rr. number of analyses.

It is important to stress that nitrogen incorporation in a-C H films always result, at least above a certain level, in a strong decrease in the tetrahedrally bonded carbon atom fraction. Raman spectroscopy also gives support to this observation, because the increase in the size of graphitic clusters only can proceed with also increasing sp fraction. 

Expressing the concentrations of the components of a solution in terms of mole fractions or atom fractions is adequate only in some limiting cases of solution behaviour. A more... 

If the atom fraction of deuterium in each separated coal product, given in Table I, is defined as Fy, the atom fraction of protium in the same coal product is therefore 1-Fy. The total amount of protium and deuterium in a given product fraction y is normalized to unity according to Equation 3,... 

It was assumed that the nickel crystallites are rapidly enveloped in a skin of a copper-rich alloy, from which diffusion towards the center of each crystallite then takes place. If xx and x2 are the atomic fractions of copper in the two equilibrium phases and x is the atomic fraction of copper in the alloy film under consideration, then the crystallites in the annealed film may have a variety of forms. Solid solutions occur at either end of the composition range but the values of Xi and x2 at 200°C are <0.1 and 0.8. Hence, over much of the composition range (i.e., where x lies between X and xi), the Cu-Ni films should consist of crystallites with a kernel which is almost pure nickel (composition xi) enveloped in a skin of a copper-rich alloy (composition x2). Eventually, when x is only slightly larger than Xi, the alloy skin does not completely surround the nickel crystallites small patches of alloy (x2) and almost pure nickel ( ci) are both exposed. 

All binary alloy compositions listed in this chapter will be written as atomic fractions. For convenience, we will define the symbol a/o as 100% N, where N is the atomic fraction of an element in the alloy. For example, an alloy containing 20% atomic fraction aluminum will be referred to as 20 a/o Al. 

Fig. 10. Atomic fraction of aluminum in the Ag-Al alloy, I x, as a function of potential based on the sampled-current voltammograms in Figure 9. The Ag(I) concentrations were ( ) 5.0, (A) 10.0, ( ) 15.0, (T) 20.0, and ( ) 25.0 mmol L-1. Adapted from Zhu et al. [89] by permission of The Electrochemical Society.

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