About the Authors

Heng Liu

liuheng@mail.dlut.edu.cn

Affiliation Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian, China

Xingyuan Wang

Affiliation Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian, China

Guozhen Tan

Affiliation Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian, China

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: LH. Performed the experiments: LH WX. Analyzed the data: LH TG. Contributed reagents/materials/analysis tools: LH. Wrote the paper: LH.