349453.fig.002a
(a)
349453.fig.002b
(b)
349453.fig.002c
(c)
349453.fig.002d
(d)
Figure 2: MDFS data: (a) oscillation amplitude of the externally driven cantilever showing approach (blue) and retraction (red); (b) the force-distance curve for the undriven cantilever at the same scan setting in (a); (c) waterfall plot acquired simultaneously with the force curve presented in (b); (d) plot of frequency of maximum amplitude (green) and scanner displacement (black) versus time.