Helfrich 1973 elastic-membrane bending energy density (kappa/2)(c1+c2-c0)^2 + kappa_bar c1 c2; basis of vesicle shape + membrane-undulation spectroscopy.
Helfrich 1973 elastic-membrane bending energy density (kappa/2)(c1+c2-c0)^2 + kappa_bar c1 c2; basis of vesicle shape + membrane-undulation spectroscopy.