Thermodynamics with density and temperature dependent particle masses and properties of bulk strange quark matter and strangelets

Thermodynamic formulas for investigating systems with density- and/or temperature-dependent particle masses are generally derived from the fundamental derivation equality of thermodynamics. Various problems in the previous treatments are discussed and modified. Properties of strange quark matter in bulk and strangelets at both zero and finite temperature are then calculated based on the new thermodynamic formulas with a new quark mass scaling, which indicates that low-mass strangelets near {beta} equilibrium are multiquark states with an antistrange quark, such as the pentaquark (u{sup 2}d{sup 2}s) for baryon number 1 and the octaquark (u{sup 4}d{sup 3}s) for dibaryon, etc.