Near neighbours

Jarvis R A and E A Patrick 1973. Clustering Using a Similarity Measure Based on Shared Near Neighbours. IEEE Transactions in Computers C-22 1025-1034. 

Figure 8.38 Curve fitting of Mo extended X-ray absorption fine structure (EXAFS) for Mo(SC6H4NH)3, taking into account (a) sulphur and (b) sulphur and nitrogen atoms as near neighbours. (Reproduced, with permission, trom Winnick, H. and Doniach, S. (Eds), Synchrotron Radiation Research, p. 436, Plenum, New York, 1980)...

Figure 8.24 Schcmaiic diagram of the layer structure of CuCN.NH showing the tridentate CN groups each Cu is also bonded to 1 NH molecule at 207 pm. Note also the unusual 5-coordination of Cu including one near neighbour Cu at 242 pm (13 pm closer than Cu-Cu in the metal). The lines in the diagram delineate the geometry and do not represent pairs of electrons.

The denser packing of the molecular chains results in stronger interactions between segments and their near neighbours by means of van der Waals forces which are responsible for the rigidity of glassy polymers just as in the solidification of high polymers [56]. The important features of van der Waals forces are [57, 111] ... 

Jarvis RA, Patrick EA. Clustering using a similarity measure based on shared near neighbours. IEEE Trans Comput 1973 C-22 1025-34. 

Figure 3.30. Analysis of the cP4-AuCu3 type structure. Coordination and interatomic (reduced) distances. The total number (n) of near-neighbour atoms around Au and Cu are plotted as a function of their reduced distances from the reference atom. The symbols of the surrounding atoms are indicated. Notice the similarity between the two histograms.

Reduced dimensional parameters (strain parameters and near-neighbours diagrams) By comparing the space-filling theoretical curves and the actual values of intermetallic phases it has been observed that an incompressible sphere model of the atom gives only a rough description when discussing metallic structures. 

Figure 4.24. Near-neighbour diagrams for binary phases calculated according to Pearson (1972) for a few structural types. The lines calculated for the different interatomic contacts are shown. The numbers of contacts X-Y, Y-X, X-X, etc. are indicated. The experimental values determined for the various compounds are contained, for each structure type, within the hatched fields, (a) XY3 compounds belonging to the cP4-AuCu3 structural type (b) XY2 Taves phases of the cF24-Cu2Mg type (c) XY compounds of the cF8-ZnS structural type. Notice the importance of the high coordination contacts in the more metallic phases, whereas in the ZnS-type compounds the role of the chemical bond factor is clearly relevant.

In a normal tetrahedral structure every atom has 4 near neighbours at the vertices of a surrounding tetrahedron. The shape of such a tetrahedron will determine regular and distorted tetrahedral structures. 

The operator s first point of contact is the customer. After providing proof of identity, essential questions must be asked such as what are the arrangements with stewards, security and emergency services Are the police and near neighbours aware of the display Where is the nearest telephone and emergency exit Are there any first-aid or other facilities ... 

Equation (1.47) can be generalized to the 2D case of an (n x m) lattice. The expression then becomes, again only valid for near-neighbour interactions but without cyclic boundary conditions ... 

According to this proposal, the high selectivity of TS-1 should be ascribed to the fact that H2O2 can be decomposed into H2O and O2 only when two or more Ti(IV) are in near-neighbour positions, a very unlikely possibility in TS-1. This results in a low decomposition rate of H2O2 which favours the transfer of peroxidic oxygen to the organic compounds. 

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