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.
(A) Positive forward (B) Positive reverse (C) Negative forward (D) Negative reverse. Size of scale bar is 100 μm. Detailed dimension of the structure is displayed in magnified pictures on the right of each image.
