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.
CTF profiles as a function of spatial frequency. The output of SPIDER command TF L is in red. The blue curve, which preserves low spatial frequencies, will be used. Note that beyond 0.02 Å−1 the two profiles are the same, appearing as a purple line.
