In the previous study, modified classical homogeneous nucleation theory considering the free energy change in parent phase was developed, which revealed the presence of a minimum in nucleation curve (the curve of total free energy change versus nuclear radius) of binary solution. In the present study, using the modified theory, numerical calculations were performed for other various systems; liquid and solid solution systems with compound nuclei and mixed gas systems with liquid nuclei. The calculated results also proved the presence of a minimum in each nucleation curve of these various systems. The minimum in nucleation curves has been passed unnoticed by many researchers in various fields. Therefore, Kevin equation is misunderstood as it describes the maximum state. However, it should be the minimum state that Kelvin equation describes. The large difference between the critical radius size of water droplet calculated at the maximum point (17 A at 200% humidity) and the observed micron order size of water droplet in cloud and fog can be explained through considering that the micron order droplet should be in the minimum state. The contradiction comes from the misunderstanding that a nucleation curve has only a maximum. Therefore, it is essential to review the various nucleation phenomena on the standpoint of the presence of a minimum. The influence of the change of initial content, initial pressure, interfacial tension. and number of nuclei in I mol system to the behavior of nucleation curve was discussed. (c) 2007 Elsevier B.V. All rights reserved.