Fudan Univ, Dept Phys, Shanghai 200433, Peoples R China
; China Ctr Adv Sci & Technol, World Lab, Beijing 100080, Peoples R China
; Acad Sinica, Inst High Energy Phys, Beijing 100080, Peoples R China
It is found that the radius of a stable strangelet decreases as the temperature increases in a quark mass density-dependent model. To overcome this difficulty, we extend this model to a quark mass density- and temperature-dependent model in which the vacuum energy density at zero baryon density limit B depends on temperature. An ansatz which reads B = B-0 [1-a(T/T-c) + b(T/T-c)(2)] is introduced and the regions for the best choice of the parameters are studied.