Shielding function

The theoretical understanding of xenon chemical shifts was placed on a firm footing by the work of Jameson and co-workers, who were able to reproduce the chemical shifts for xenon clusters of different size in NaA and AgA zeolites remarkably well [13-17]. However, the procedure is not trivial, as it requires a knowledge of the structure, the shielding functions for all possible Xe-framework atom pairs, the Xe-framework atom potential functions, and a calculation over the accessible dynamic states of the xenon atoms in the cage. To work back from chemical shifts to pore size clearly is not trivial, so the establishment of some general shift - size correlations still is extremely useful. 

Some water models use a shielding function, S r), that changes the contribution to E,- from the charge at 26,30,31,37... 

The shielding function differs from 1 only at small distances and accounts for the fact that at small separations the electric field will be modified by the spatial extent of the electron cloud. For larger molecules, the interactions from atoms that are directly bonded to atom i and are separated by two bonds or less (termed 1-2 and 1-3 bonded interactions) do not typically contribute to... 

Dendrimers - Molecular Trees Dendrimers have systematic branching structures and they are built in a stepwise manner. Supermolecules from this family can be used to shield functional groups and to collect energy. 

In Eq 7.25 ( ) is the maximum packing volume fraction. Thus, the magnitude of the shielding function My) depends on the reduced volume fraction, = ( ) / ( ). At low concentration, —> 0, the shielding factor vanishes and Einstein s relation is recovered. However, at high concentration, —> 1, the shielding function and relative viscosity both... 

Individual shields function autonomously (e.g., respond to a trigger) to detect, diagnose, and decontaminate... 

With this failure, the block elements in the core column above could drop a short distance and became jammed on the damaged post. The functions of the post would continue to be met since the core column flow would be maintained and it would be possible to insert reactivity control material. Safe shutdown of the reactor would not be affected, nor would the flow mixing or shielding functions of the posts. 

PRODUCTION UNIT One protective shield FUNCTION Protect engine, guide air REQUIREMENT High toughness-to-weight ratio FUNCTIONAL UNIT Car-km... 

The installation of such valves in the core cooling injection system, in addition to the benefits associated to the leak proof characteristics, ensures, during normal operation, a pressure shielding function on the upstream check valves. Therefore, these valves do not remain forced in the closed position for long... 

Before leaving the subject of shielding, it should be mentioned that the water in the process tube has a shielding function. 

In Eq. 7.25, 4>ni is the maximum packing volume fraction. Thus, the magnitude of the shielding function X(y) depends on the reduced volume fraction,

[Pg.743]

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