Jiping Huang's group (Department of physics, Fudan University) and Cheng-Wei Qiu's group (Department of Electrical and Computer Engineering, National University of Singapore) collaborated to complete this study published in National Science Review. They found a new mechanism to generate asymmetric temperature profiles without dynamic modulation. Specifically, graded thermal conductivities could induce the imitated advection in pure and passive conduction, which has a similar temperature field effect to the realistic advection. With the imitated advection, heat could spontaneously converge to the center like black holes.