Random network

There are two classes of solids that are not crystalline, that is, p(r) is not periodic. The more familiar one is a glass, for which there are again two models, which may be called the random network and tlie random packing of hard spheres. An example of the first is silica glass or fiised quartz. It consists of tetrahedral SiO groups that are linked at their vertices by Si-O-Si bonds, but, unlike the various crystalline phases of Si02, there is no systematic relation between... 

The stmcture of vitreous siUca is a continuous random network of SiO tetrahedra, linked through the sharing of corners. It differs from crystalline sihca ia having a broader distribution of Si—O—Si bond angles and a more random distribution of one tetrahedron with respect to another (44). The density is 2.2 g/cm. ... 

For recombinant resilin, we found that data from the CD spectra (Figure 9.4), x-ray diffraction pattern (Figure 9.5), and NMR were consistent with resilin being an amorphous random network... 

Aaron, B.B. and Gosline, J.M., Elastin as a random-network elastomer A mechanical and optical analysis of single elastin fibers. Biopolymers, 20, 1247-1260, 1980. 

Electron microscopy and X-ray diffraction experiments conducted on resilin-containing insect cuticle provided further support for resilin existing in the rubbery state as a crosslinked random network of protein chains. No fine structure was revealed by the electron microscopy experiments and zero crystallinity could be detected from the X-ray diffraction experiments. Furthermore, the diffraction... 

Pajek http //vlado.fmf.uni-lj.si/pub/networks/pajek/ Network building software Random networks, shortest paths. Many options for network building 106... 

The two quantities p and pt are satisfactory for the quantitative description of any random network structure. Alternative quantities sometimes are used to advantage, however. Instead of pt, one may prefer to specify the number N of primary molecules... 

For anything as complex as a random network structure, this account unquestionably is an oversimplification. Experiments which will be... 

Wood and Hill consider that the role of fluoride in these glasses is uncertain. Phase-separation studies suggest that the structure of the glass might relate to the crystalline species formed, in which case a microcrystallite glass model is appropriate. But other evidence cited above on the structure-breaking role of fluoride is compatible with a random network model. 

Randomly - Crosslinked PDMS. The polydimethylsiloxane (PDMS) used to make random networks was obtained from General Electric. Membrane osmometry showed to be 430,000 g/g-mole. The polymer was mixed with various amounts of a free-radical crosslinking agent, dicumylperoxide (Di-Cup R, Hercules Chemical Co.). Samples were then pressed into sheets and crosslinking was effected by heating for 2 h at 150°C in a heated press. Mc values were calculated using equation 2, and are included in Table I. 

The first theory of the structure of glass to become widely accepted was that of Zachariasen (1932), called the random network theory [now commonly referred to as the continuous random network (CRN) theory]. This arose... 

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