Normalized solutions for a fourth-order Schrödinger equation with a positive second-order dispersion coefficient

In this paper, we study normalized solutions to a fourth-order Schrödinger equation with positive second-order dispersion coefficient in the mass supercritical regime. Unlike well-studied case where term is zero or negative, geometrical structure of corresponding energy functional changes dramatically and makes solution set richer. Under suitable control mass, find at least two radial solutions, ground state an excited state, together some asymptotic properties. It worth pointing out that considered repulsive case, compactness analysis related Palais-Smale sequences becomes more challenging. This forces implementation refined estimates Lagrange multiplier level obtain solutions.