小中大【讨论帖】标准聚乙烯膜片
标签:聚乙烯 ars pl sta ta
Polystyrene samples mounted on a standard wheel must be replaced after five years from the date of issue.
Because card-mounted standards are handled regularly and, therefore, exposed to potential contamination, damage and degradation, they must be replaced after two years from the date of issue.
这段话是关于红外标准聚乙烯膜片的,提到了两种膜片,有谁见过第一种?拍个片片看看是什么东东?