Physical department, Hebei University, Baoding, China, 071002
College of Electronic and Informational Engineering, Hebei University, Baoding, China, 071002
College of Electronic and Informational Engineering, Hebei University, Baoding, China, 071002
College of Electronic and Informational Engineering, Hebei University, Baoding, China, 071002
Physical department, Hebei University, Baoding, China, 071002
Physical department, Hebei University, Baoding, China, 071002
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