Copyright © 2011 Yige Zhao et al. This is an open access article distributed under the
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We study the existence of positive solutions for the boundary value problem of nonlinear fractional differential equations , , , where is a real number, is the Riemann-Liouville fractional derivative, is a positive parameter, and is continuous. By the properties of the Green function and Guo-Krasnosel'skii fixed point theorem on cones, the eigenvalue intervals of the nonlinear fractional differential equation boundary value problem are considered, some sufficient conditions for the nonexistence and existence of at least one or two positive solutions for the boundary value problem are established. As an application, some examples are presented to illustrate the main results.