Exact Solutions and hypothesis on Phase Transition in the   Polyelectrolite Model of DNA
  The two-dimensional generalization of the Polyelectolite model of DNA is proposed. It is reduced to the boundary problem for nonlinear completely integrable equation $\sh$-Gordon. In the linearisible version the exact solution is constructed and its asymptotic is found. The soliton solutions of nonlinear equation are calculated that allowed tells about the possibility of the structural phase transition in the considered system (DNA+polyelectrolite) on the temperature. 
E.Sh.Gutshabash