In situ measurement of the fractal dimensionality of ultrafine aerosol particles

Schmidt-Ott, A.
March 1988
Applied Physics Letters;3/21/1988, Vol. 52 Issue 12, p954
Academic Journal
The fractal dimension df of gas phase agglomerated particles is measured in situ for the first time. This is done by comparing aerodynamic radii R0 and Rc1 before and after tempering. By tempering, agglomerates are collapsed into close-packed clusters of df=3. It is shown that the equation M∼Rdf0 , where M is the agglomerate mass, holds almost down to R0=Rc1 =Rm (monomer radius), making df a very useful quantity for aerosol characterization. The measurement yields df[bar_over_tilde:_approx._equal_to]2.18 for Ag agglomerates with Rm[bar_over_tilde:_approx._equal_to]7.5 nm. df is predicted to be material dependent.


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