[1] Yonsei Univ, Dept Mat Sci & Engn, Seoul 03722, South Korea
[2] Stanford Univ, Ctr Turbulence Res, Stanford, CA 94305 USA
[3] Pohang Univ Sci & Technol, Dept Mech Engn, Pohang 37673, South Korea
[4] Ecole Polytech Fed Lausanne, Soft Transducers Lab LMTS, Neuchatel, Switzerland
[5] Cascade Technol Inc, Palo Alto, CA 94303 USA
[6] Stanford Univ, Inst Computat & Math Engn, Stanford, CA 94305 USA
[7] Univ Glasgow, James Watt Sch Engn, Glasgow City G12 8LT, Scotland
[8] Univ Cambridge, Dept Mat Sci & Met, 27 Charles Babbage Rd, Cambridge CB3 0FS, England