“…This topic has received a great 1 Email address :3425linran@sohu.com 2 Corresponding author. Email address :fwliu@xmu.edu.cn,f.liu@qut.edu.au deal of attention in the last decade [7,15,[22][23][24], especially in the fields of viscoelastic materials [1,10,11,27], electrochemical processes [8], dielectric polarization [28], colored noise [29], anomalous diffusion, signal processing [21], control theory [24], advection and dispersion of solutes in natural porous or fractured media [2,3] and chaos [20]. Djrbasjan et al [6] considered the Cauchy problem with multi-term fractional derivatives, and proved the Cauchy problem has a unique solution.…”