Acknowledgements

This work was supported by the Starting fund at Zhejiang University, National Natural Science Foundation of China (No. 61401307), Hebei Province Foundation of Returned oversea scholars (CL201707), Hebei Province Project of Science and Technology R & D (11213565), and Hebei Province Natural Science Foundation (No. E2016202341). The authors would like to thank Yaru Xue, Shaohuan Zu, and Wei Chen for helpful comments and suggestions on the topic of noise attenuation.