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) Surface 1 Exposure 4 (SEM BE 600×), (b) Surface 1 Exposure 7 (SEM BSE 600×), (c) Surface 1 Exposure 8 (SEM BSE 600×), (d) Cross-section 1 Exposure 4 (SEM BSE 600×), (e) Cross-section 1 Exposure 7 (SEM BSE 600×), and (f) Cross-section 1 Exposure 8 (SEM BSE 600×).
