Thanh toán linh ho?t: Thanh toán ti?n m?t tr?c ti?p khi nh?n tem ho?c thanh toán tr??c qua tài kho?n.Cold finger-An extended copper rod extending alongside the inside of your electron column. When its reservoir is retained crammed with liquid nitrogen, the rod draws in contaminants That may usually degrade the chamber's vacuum.– T?o s? c?nh t