Figure 1.
Drawing of a polymer network (not to scale). The shaded test chain can only move along the tube, because lateral displacements are prohibited by the topological constraints (indicated by the asterisks) imposed by some solid chains.
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.