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.
3D-printed helicoidal fibre cores (left) and design models (right) (a) Plain. (b) Ring. (c) Helix. (d) An optical image of a representative cylindrical specimen using the plain fibre core. The black scale bar represents 5 mm. (Online version in colour.)
