school of mathematics and statistics;
hefei normal university;
Hefei 230601;
P.R.China;
school of mathematical science;
university of science and technology of china;
Hefei 230026;
P.R.China;
Parabolic; equation; Li-Yau; type; Harnack; differential; inequality; local; Hamilton; typegradient; estimate; fast; diffusion; equation; Porous; media; equation;