Above: A solid can have a fractal surface in three different ways.
In a surface fractal (above) only the surface (red) is fractal.
Below: In a mass fractal, the solid (black) and the surface are fractal.
In a pore fractal (below), the pore space (white) and the surface are
fractal.
Surface fractals and mass fractals have been known for a long time.
Scientists have now discovered the first case of a pore fractal. The
solid is carbon, and the fractal pore space forces molecules (blue circles)
to move along a fractal path. The fractal path amounts to motion in
a space with noninteger dimension. The molecules' continuous contact
with the wall makes them feel a very different environment than if they
were moving in the pore space of a surface fractal or mass fractal.
Reported by: Pfeifer
et al., Physical Review Letters, 18 March 2002.
Associated
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