All the irradiation treatments were conducted in Guangdong
Radiation Technology Development Center with a Colbalt-60
source of gamma radiation (2.22 PBq). Reference standard and
routine dosimetry were done with the Fricke system (ASTM E1026-
13, 2002). This dosimetry systemwas calibrated in accordance with
the international standard ISO/ASTM 51261 (2002) and ASTM
E1026-13 (2002), and the uncertainty of the measured value was
calculated according to ISO/ASTM 51707 (2002