Loose clusters

As two particles approach in a liquid their charge fields may interact and form two minima as depicted in Figure 6.8. If the particles approach to a distance Li, known as the primary minimum they aggregate to form a configuration with minimum energy - and rapid coagulation is said to take place. On the other hand, if the particles remain separated at a distance L2, the secondary minimum, loose clusters form which do not touch. This is known as slow coagulation and is the more easily reversed. 

Additional types of k C-k E chelating ylide complexes merit mentioning here, in addition to the species already presented, and some of them are shown in Scheme 24. The first is formed by ylides containing a pyridine functionality as substituent of the ylidic carbon. This type of ligand has allowed the S3mthesis of many loose clusters (82) of Cu, Ag, and Au which show weak metal( / °)-metal( / °) interactions. These facts have prompted the definition of a new phenomenon numismophilicity) to account for these weak interactions, uniquely shared by the three coinage metals [164]. Nitrogen and sulfur keto-stabilized ylides have been reacted with Pt and... 

In the case of diffusion-controlled A + B —> 0 reaction distinctive spatial distributions of reactants observed in computer simulations (e.g., [21]) are qualitatively the same as were presented earlier in Figs 1.20 and 1.21. Quite similar aggregation of similar particles into loose clusters occurs in agreement with a distinctive block-structure characterized by the diffusion length Id = f Dt shown in Fig. 2.8. When the reaction is controlled by the particle diffusion, these clusters (domains) are less pronounced since diffusion is known to smooth nonuniform particle distribution created in a course of reaction. 

As medium, a 4.5% aqueous malt extract solution having a pH of 5.4 is employed. One liter of this solution is sterilised in a 2-liter Erlenmeyer flask for 20 minutes at 110° C., and then inoculated with about 5 X10 (to the) 8 th) conidia of a 20-day old agar culture of the new strain and incubated for 3 days at 23° C. on a rotating shaking machine. A compact culture of fine mycelium flakes is formed. The flakes consist of loose clusters of hyphae and have a diameter of 2-4 mm. No alkaloids can be detected. 

There is ample experimental evidence that identically charged polymers in the presence of ordinary univalent counterions have a tendency to form loose clusters in solution [65-70], and we have asked whether the attractive polyion-polyion potential discussed in Sec. Ill can stabilize a finite-sized cluster of parallel rodlike polyions without leading to precipitation [71,72]. The theoretical problem is complicated by a failure of pairwise additivity the work of assembling N polyions is not equal to the work of assembling the N(N — l)/2 polyion pairs, each in isolation from the other N 2 polyions. To be sure, the Debye-Htickel interaction term for a cluster (the generalization of Eq. 5 above) takes the form of a pairwise sum over polyions,... 

Ray J, Manning GS. The formation of loose clusters in polyelectrolyte solutions, submitted. 

To aggregate or coalesce into small lumps or loose clusters or into a flocculent mass or deposit. 

To AGGREGATE or COALESCE into small LUMPS or loose CLUSTERS or into a FLOCCULENT mass or DEPOSIT. 

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