Molecular mechanics cross term function

Sturz and DoUe measured the temperature dependent dipolar spin-lattice relaxation rates and cross-correlation rates between the dipolar and the chemical-shift anisotropy relaxation mechanisms for different nuclei in toluene. They found that the reorientation about the axis in the molecular plane is approximately 2 to 3 times slower than the one perpendicular to the C-2 axis. Suchanski et al measured spin-lattice relaxation times Ti and NOE factors of chemically non-equivalent carbons in meta-fluoroanihne. The analysis showed that the correlation function describing molecular dynamics could be well described in terms of an asymmetric distribution of correlation times predicted by the Cole-Davidson model. In a comprehensive simulation study of neat formic acid Minary et al found good agreement with NMR relaxation time experiments in the liquid phase. Iwahashi et al measured self-diffusion coefficients and spin-lattice relaxation times to study the dynamical conformation of n-saturated and unsaturated fatty acids. 

All these results taken together allow us to visualize a likely mechanism for the catalytic cycle as a rotation in terms ofthe ye-subunit domain within the [a p]3in F, as illustrated in Fig. 33. After many enzyme turnovers and the rotation ofthe ye subunit domain has stopped, 1/3 ofthe ye subunit domains are expected to end up at each of the three a p pairs, consistent with the finding of approximately equal amounts of a 8 y, a 8 and a 5 e in the cross-linked products. The functional roles of these three small subunits will be discussed in Section I V.C. 1. below on the basis of their molecular structures. 

The resulting mixture has a quite complicated structure (Table 37-2). Normally, the amounts of additives are given in terms of parts per hundred parts of rubber, phr. The rubber provides the elastomer with the required viscoelastic properties. Sulfur forms the cross-link bridges between molecular chains the cross-linking shifts the property spectrum from viscous towards elastic. Carbon black as filler fulfills two functions to cheapen the product as a classical filler, and to increase the mechanical strength as what is known as... 

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