Polymer translocation in a double-force arrangement S. T. T. Ollila, K. F. Luo, T. Ala-Nissila and S. -C. Ying Eur. Phys. J. E, 28 4 (2009) 385-393 Published online: 27 March 2009 DOI: 10.1140/epje/i2008-10429-9