• There are several distinct annealing stages.
• Elemental carbon exists in two well-defined crystalline allotropic forms.
• These compounds have clearly ( or sharply ) defined thermodynamic properties.
• These copolymers have a less pronounced ( or marked ) block structure.
• He has observed clear-cut changes of crystal habit.
• The excited state-producing step occurs in a separate, well-defined reaction.
• Well-marked differences have been discovered between ...