Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Schematic illustration of forces acting on a cell according to the potential function given by Eq. 1. The force on each cell surface has two components: one parallel and the other perpendicular to the surface. The angle θ defines the rectangular, up-, or downtrapezoidal shape. The mathematical expression of the parallel and the perpendicular components of forces are explicitly shown and illustrated in the text. To see this figure in color, go online.
