Segment clusters

Figure 2. From the left Bge cluster segments in form of two 48-rings (Fig. 2a), three 32-rings (Fig. 2b), four 24-rings (Fig. 2c) and six 16-rings (Fig. 2d) with the structures of (24, 24), (16,16), (12,12) and (8,8) armchair nanotubes, respectively.

Cha, S., McCleary, K. and Uysal, M. (1995) Travel motivations of Japanese overseas travelers A factor-cluster segmentation approach. Journal of Travel Research 34 (1), 33-39. 

The junctions of the cluster network have definite sizes (the length of the cluster segment is assumed to be equal to that of the polymer statistical segment [1]. 

In many cases, it is also helpful to have the path repel itself so that the transition pathway is self-avoiding. An acmal dynamic trajectory may oscillate about a minimum energy configuration prior to an activated transition. In the computed restrained, selfavoiding path, there will be no clusters of intermediates isolated in potential energy minima and no loops or redundant segments. The self-avoidance restraint reduces the wasted effort in the search for a characteristic reaction pathway. The constraints and restraints are essential components of the computational protocol. 

A helix bundle is a protein composed of a series of rodlike helical domains linked by flexible segments and inserted into a membrane to form a cluster of helices roughly parallel to one another and perpendicular to the plane of the membrane. 

We assume that polymer molecules consist of a large number of chain segments of equal length, joined by flexible links. Each link then occupies one site on the lattice. The solution has to be sufficiently concentrated that the occupied lattice sites are distributed at random, rather than having them clustered together in a non-random way. 

A more realistic model of this solution was developed in 1950 by Rory and Krigbaum, and assumes that the polymer consists of approximately spherical clusters of segments. These clusters have a maximum density of segments at their centre and this density decreases with distance from the centre in an approximately Gaussian distribution. 

The distances between compounds in Fig. 31.7 are not notably affected by the transformation in comparison with the previous Fig. 31.6. This biplot allows more easily to perceive the correlations between measurements. Three clusters are now put in evidence, namely (1) DMSO and DMF, (2) ethanol and propanol, (3) octanol, dioxane, THF and methylenedichloride. The line segments drawn from the origin have been added to emphasize these groupings. Unipolar axes could have been defined here in the same way as in Fig. 31.6. Bipolar axes on the column-standardized biplot, however, cannot be interpreted directly in terms of the original data in X. 

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