Fig. 1. The phase portraits of system (8): (a) g < –g₀, (b) g = –g₀, (c) –g₀ < g < 0, (d) g = 0, (e) 0 < g < g₀, (f) g = g₀, (g) g > g₀.

Fig. 2. The profiles of traveling wave solutions of Eq. (2). (a) Kink wave solution (15), (b) singular wave solution (17), (c) periodic singular wave solution (19).

Fig. 3. The profiles of traveling wave solutions of Eq. (2). (a) Periodic wave solution (22), (b) solitary wave solution (24), (c) singular wave solution (29).