– Quang h\u1ee3p l\u00e0 qu\u00e1 tr\u00ecnh s\u1eed d\u1ee5ng n\u0103ng l\u01b0\u1ee3ng \u00e1nh s\u00e1ng \u0111\u1ec3 t\u1ed5ng h\u1ee3p ch\u1ea5t h\u1eefu c\u01a1 t\u1eeb c\u00e1c nguy\u00ean li\u1ec7u v\u00f4 c\u01a1\n<\/p>\n\n\n\n
– Ph\u01b0\u01a1ng tr\u00ecnh t\u1ed5ng qu\u00e1t:\n<\/p>\n\n\n\n