Standard practice for making and using precracked double beam stress corrosion specimens 裂缝前双束应力腐蚀样品的制作和使用标准实施规范
Design of dynamic focusing circuit for testing system of projection cathode ray tube with double beams 双束投影管测试台中动态聚焦电路的研制
Test method for measurement of thickness of transparent or opaque coatings by double - beam - interference microscope technique 用双束干涉显微技术测量透明涂层或不透明涂层厚度的试验方法