Random bond model

In section C2.5.2 we considered a variational-type theory to treat the thennodynamics of the random hydrophobic-hydrophilic heteropolymer. Here we describe a limiting behaviour of the random bond model [30]. 

One can account the presence of non magnetic impurities introducing random interaction J. However, the corresponding random-bond model is conjectured to exhibit universal critical behavior identical to the site-diluted model K. Hukushima, J. Phys. Soc. Jap. 69 (2000) 631 P. E. Berche, C. Chatelain, B. Berche, W. Janke, Eur. Phys. J. B 38 (2004) 463. 

From tire above equation it follows tliat in tire mean-field limit replica symmetry is not broken. This makes tire GLO model conceptually simpler to interirret tlian tire random bond heteropolymer model discussed in tire appendix. 

We examined the role of vector percolation in the fracture of model nets at constant strain and subjected to random bond scission, as shown in Fig. 11 [1,2]. In this experiment, a metal net of modulus Eo containing No = 10" bonds was stressed and held at constant strain (ca. 2%) on a tensile tester. A computer randomly selected a bond, which was manually cut, and the relaxation of the net modulus was measured. The initial relaxation process as a function of the number of bonds cut N, could be well described by the effective medium theory (EMT) via... 

Fig. I I, The role of vector percolation in the fracture of model nets at constant strain and subjected to random bond scission.

A much more satisfactory random network model has been discussed by Alben and Boutron 82h They used a model, proposed by Polk 78> for Ge(as), scaled to fit the observed nearest neighbor 00 distance of H20(as), and with H atoms added to the OO bonds according to the Pauling ice rule that guarantees the presence of only H20 molecules 65>. In the Polk model the bond length is everywhere the same and the 000 angles are distributed with root mean square deviation of 7° about 109°. For the case of Ge(as), the observed and model radial distribution functions are in excellent agreement. 

The General Bond-Weighted Random Scission Model.485... 

THE GENERAL BOND-WEIGHTED RANDOM SCISSION MODEL 18.3.1 Overview... 

---