Quasibinary approximation

Notice that this result shows that the so-called quasibinary approximation where the concentration is supposed to have the same value... 

In spite of the deviation from the mean-field type behavior, the coexistence curve of the blend B was well described by the Flory-Huggins theory under the quasibinary approximation with the interaction parameter x that was consistent with those estimated by the molecular weight dependence of cloud points. 

The first possibility is considered in the quasibinary system A—(Bi xCx) with limited solubility, but without intermediate phases. Analytical and numerical methods were used to find the solutions, which correspond to the case of a diffusion path going through the conode (at the interphase boundary, the concentrations jump between two edge points of the conode). At that the inter-diffusion in the couple A, solid solution (BC) was treated in the approximation of parabolic movement of the boundary. On the basis of diffusion equations for a and /3 phases and two equations for flux balance (for A and B components), one has... 

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