“…7) ρ(x) = (1 + η|x| 2 ) −l , with l > N 2 , η > 0, where, obviously, one can obtain the estimates that |∇ρ| ≤ C √ ηρ and |∆ρ| ≤ Cη ρ. Problem (1.1)-(1.2) has many relevant physical applications (e.g., see [28] for a summary), and its dynamics have been studied extensively by many authors; see [5,6,7,13,27,28] and the reference therein. The existence and smoothness of the global attractor for the case where the spacial domain is bounded have been achieved recently, e.g., see [6,7,27,28].…”