Core outer

There are also very reliable approximate methods for treating the outer core states without explicitly incorporating them in the valence shell. 

Various newer and more corrosion-resistant alloys are now available for use, including low nickel alloys, such as Inconel 800 (35% Ni, 20% Cr, 45% Fe). Low nickel alloys, in particular those with with less than 0.03% cobalt, are required to limit the development of a cobalt-induced, outer-core radiation field within the SG. 

Corrosion products include iron oxide (Fe203), ferrosoferric oxide (Fe304), nickel oxide (NiO), cobalt oxide (CoO), and complex Fe, Ni, and Co oxides. Cobalt in particular may present a problem (as cobalt59, a naturally occurring isotope), and when present as a contaminant in nickel alloys (such as Inconel 800), may enhance the development of an outer-core radiation field (see Section 7.4.1). 

Cobalt-induced, outer-core radiation field 266... 

To avoid confusion with the shells of the shell model of the nucleus we shall refer to the layers of spherons by special names the mantle for the surface layer, and the outer core and inner core for the two other layers of a three-layer nucleus. 

Thus for the neutron configuration ls22s2lp6ld103s22p62d10l/14lp18(lA 11/2)12 we assign Is2 to the inner core (2 neutrons), 2s2lp6ld10 to the outer core (18 neutrons), and the remainder (62 neutrons) to the mantle. 

The Assignment of Nucleons to Layers by Use of the Packing EquaMon.—Equation (1) has been applied in the assignment of neutrons to the mantle, outer core, inner core, and innermost core (for N very large), with the results shown in Figure 2. 

Fig. 2.—A diagram showing the ranges of values of the neutron number N in which successive uubsubshells of the mantle, outer core, and inner core are occupied by neutrons, as calculated with use of the packing equation. Observed values of spin and parity of odd N and odd Z nuclei are indicated by circles and squares.

Magic number Mantle Core or outer core Inner core... 

The close-packed-spheron theory8 incorporates some of the features of the shell model, the alpha-particle model, and the liquid-drop model. Nuclei are considered to be close-packed aggregates of spherons (helicons, tritons, and dineutrons), arranged in spherical or ellipsoidal layers, which are called the mantle, the outer core, and the inner core. The assignment of spherons, and hence nucleons, to the layers is made in a straightforward way on... 

The most stable core configuration for an inner core of one spheron is KM, with an outer core of nine spherons. For icosahedral packing the outer core contains 12 spherons. These structures, which we may take as defining the limits of stability for a one-spheron inner core, have been discussed in the preceding section. 

Nuclei with an inner core of three spherons would have oblate deformation, rather than prolate. The packing is somewhat less satisfactory than for one, two, or four spherons, except for ligancy 10 (18 spherons in the outer core), which corresponds to 42 core... 

Fig. 11. (Left) An outer core of 16 spherons surrounding an inner core of three, in a linear arrangement. (Right) The same core with a portion of the mantle of the elongated nucleus. (The difference in relative sizes of core and mantle spherons is exaggerated in this and some of the other figures.)...

In the region IV 140 the inner core is a trigonal bipyramid of five spherons, surrounded by an outer core of 18 to 24 spherons (Fig. 10). The deformation is prolate, and about as great as for the region 90 to 120, in agreement with experiment. 

These fissioning nuclei (such as 8tP°i2-211> formed by reaction of Bi209 and a deuteron) have a nearly spherical normal-state structure, resembling that of the doubly magic nucleus seP m208, with an outer core of 16 spherons and an inner core of 4 spherons, shown in Fig. 6. The nucleus is excited, with vibrational energy about 25 Mev (for bismuth bombard-... 

The close-packed-spheron theory of nuclear structure may be described as a refinement of the shell model and the liquid-drop model in which the geometric consequences of the effectively constant volumes of nucleons (aggregated into spherons) are taken into consideration. The spherons are assigned to concentric layers (mantle, outer core, inner core, innermost core) with use of a packing equation (Eq. I), and the assignment is related to the principal quantum number of the shell model. The theory has been applied in the discussion of the sequence of subsubshells, magic numbers, the proton-neutron ratio, prolate deformation of nuclei, and symmetric and asymmetric fission. 

These results take into account three possible processes in series mass transfer of fluid reactant A from bulk fluid to particle surface, diffusion of A through a reacted product layer to the unreacted (outer) core surface, and reaction with B at the core surface any one or two of these three processes may be rate-controlling. The SPM applies to particles of diminishing size, and is summarized similarly in equation 9.1-40 for a spherical particle. Because of the disappearance of the product into the fluid phase, the diffusion process present in the SCM does not occur in the SPM. 

An example of recovered distribution is shown in Figure B6.1.2. It concerns the distribution of lifetimes of 2,6-ANS solubilized in the outer core region of sodium dodecylsulfate micelles8 . In fact, the microheterogeneity of solubilized sites results in a distribution of lifetimes. 

Zaidi, T. S., Fleiszig, S. M., Preston, M. J., Goldberg, J. B., and Pier, G. B. (1996). Lipopoly-saccharide outer core is a ligand for corneal cell binding and ingestion of Pseudomonas aeruginosa. Invest. Ophthalmol. Vis. Sci. 37, 976-986. 

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