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.
Force gradient (a), damping factor (b) and dissipative force (inset) as a function of the excitation frequency. Excitation frequencies: Blue = 1.13 kHz, Red = 5.13 kHz, Green = 7.13 kHz, Black = 11.13 kHz. The error bars are shifted upward for clarity.
