Limit to the linear range

The effect of midplane stretching is incorporated into the model by including the nonlinear term in the expression for radial strain in (2.2), 

The requirement that the potential energy must be stationary under variations in k, and ei at equilibrium leads to a nonlinear relationship between curvature and mismatch strain which is too involved to warrant presentation here in its most general form. However, there are two useful 

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The upper limit to the linear range was 5000 ngml, hut at concentrations >1000 ngml carry-over from the autosampler was observed. This could be reduced by extensive washing. 

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