2 . the chosen nanometer cacoj particles have been tested and analyzed through advanced instruments . 1 ) the crystal structure and average size of the nanometer cacos particles have been tested by rotatory anode harrow x - ray diffractometer 2 、采用先进的仪器对所选择的纳米碳酸钙粒子进行了测定: ( 1 )使用旋转阳极靶多晶x射线衍射仪测定其晶体结构和平均粒径大小。