Chain formation

The structure formation in an ER fluid was simulated [99]. The characteristic parameter is the ratio of the Brownian force to the dipolar force. Over a wide range of this ratio there is rapid chain formation followed by aggregation of chains into thick columns with a body-centered tetragonal structure observed. Above a threshold of the intensity of an external ahgn-ing field, condensation of the particles happens [100]. This effect has also been studied for MR fluids [101]. The rheological behavior of ER fluids [102] depends on the structure formed chainlike, shear-string, or liquid. Coexistence in dipolar fluids in a field [103], for a Stockmayer fluid in an applied field [104], and the structure of soft-sphere dipolar fluids were investigated [105], and ferroelectric phases were found [106]. An island of vapor-liquid coexistence was found for dipolar hard spherocylinders [107]. It exists between a phase where the particles form chains of dipoles in a nose-to-tail... 

Polymer and chain formation is another property of chalcogen-nitrogen compounds that distinguishes them from their oxygen analogues. In addition to the unique, superconducting poly(sulfur nitride) (SN) (1.24) (Section 14.2), a variety of poly(thiazyl) chains such as RS5N4R (1.25) (Section 14.3) have been characterized. Interest in these chains stems from their possible use as models for the behaviour of (SN) and as components in molecular materials, e.g., as molecular wires. 

For relatively long chains, average value of interaction energies of solvent molecules surrounding the chain is independent of the chain length. One more additional component of free energy of chain formation occurs because the distance between solvent molecules is defined... 

Free energy of chain formation on the surface after degradation is ... 

In S polymerization, thermal initiation will be a source of extra chains. Additional chain formation processes will cause the molecular weight to be lower than anticipated by cq. 7. Sometimes conventional thermal initiators are added with similar effect (see also eq. 12). A pre-tailing molecular weight distribution may result. 

G.7.2.2.2. Ternary Borides with Boron-Boron Chain Formation. 

Ternary Borides with Boron-Boron Chain Formation. 

C13-0111. Ethylene oxide forms a polyether by ring opening followed by chain formation. 

Ic. Cross-Linking of Polymer Chains.—Formation of chemical bonds between linear polymer molecules, commonly referred to as cross-linking, also may lead to the formation of infinite networks. Vulcanization of rubber is the most prominent example of a process of this sort. Through the action of sulfur, accelerators, and other ingredients present in the vulcanization recipe, sulfide cross-linkages are created by a mechanism not fully understood (see Chap. XI). Vulcanized rubbers, being typical network structures, are insoluble in all solvents which do not disrupt the chemical structure, and they do not undergo appreciable plastic, or viscous, flow. 

First steps to extended-peptide chain formation... 

The mechanism of action of rifaximin depends on the inhibition of DNA-dependent RNA polymerase of the target microorganisms, leading to the suppression of initiation of chain formation in RNA synthesis. 

We have presented a new system for formation of hydrocarbons from coordinated carbon monoxide. By preparing and reducing possible intermediates we have shown that an insertion step is important in the chain formation and suggest a scheme involving... 

Pahlow, M., Riebesell, U. and Wolf-Gladrow, D. A. (1997). Impact of cell shape and chain formation on nutrient acquisition by marine diatoms, Limnol. Oceanogr., 42, 1660-1672. 

The neutral polymer radicals which are produced also often undergo further reactions, which can result in chemical changes in the polymer. These reactions may include crosslinking or scission of polymer chains, formation of small molecule products, changes in the stereochemistry of the polymer chains, changes in the crystallinity of the polymer or a variety of other chemical and physical processes. 

The difference in behaviour has been attributed to the preferred formation, by cadmium(II) and mercury(II), of [MX2]oo chains in which pairs of chloride anions link metal centres to give a square planar MX/ arrangement, the octahedral coordination sphere then being completed by two monodentate bu molecules [MX2]oo chain formation does not occur for copper(II) and zinc(II) and so the anions only occupy two of the six available co-ordination sites allowing bu to act as a bidentate chelating ligand. 

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