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GB/T18781-2002《养殖珍珠分级》标准是我国珍珠行业第一部国家标准,它不但使我国的养殖珍珠分级有了依据,而且为我国珍珠行业的发展指明了方向。在国家标准中珠层厚度检测主要采用比较法、直接测量法(仲裁法)、X射线照相法,对这三种方法,笔者认为在实际
GB / T18781-2002 “pearl breeding grading” standard is the first national standard of pearl industry in our country. It not only provides a basis for the grading of pearl in our country, but also points out the development of pearl industry in our country. In the national standard bead layer thickness testing mainly using the comparative method, direct measurement (arbitration), X-ray photography, the three methods, I believe that in practice