SASLS by a peristaltic pump (EW-7553-70, Cole-Parmer Instrument Co., USA) with a Tygon tubing (Masterflex-06409-16, Cole-Parmer Instrument Co., USA) of I.D. 3.1 mm, and the sample was recycled back to the mixing vessel at a flow rate of 20 mL/min. The size of oxides formed at a constant mixing intensity was continuously measured for 30 min by use of the particle size analyzer, and fractal dimensions of those oxides were determined by SALLS [15].