In nhãn s?n ph?m có r?t nhi?u ph??ng pháp ???c s? d?ng th?c t? trong ?ó in offset và in k? thu?t s? là ?ng d?ng ph? bi?n h?n. Chilly finger-An extended copper rod extending alongside The within of the electron column. When its reservoir is saved filled with liquid nitrogen, the rod attracts contaminants That may if not degrade the chamber's