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2. Many thousands of designs have been created since a profile bust of Queen Victoria was adopted for the Penny Black in 1840.

答案: Since the Penny Black, the world's first adhesive postage st...
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什么是干法刻蚀?干法刻蚀相比于湿法腐蚀的优点有哪些?

答案: 干法刻蚀(Dry Etching)是一种使用气体或等离子体来去除材料的微细加工技术,它在半导体制造、微电子、微机电系统(...
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