一些食品来源于usda的食品与营养日常研究数据库(2)，被分类为开头为5,7,9的五个数字组成的标识。

Some foods are from the USDA's food and Nutrient Database for Dietary Studies 2, identified by a 5-digit number starting with 5, 7, or 9.

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这种由加拿大造币公司和锡克拜（SICPA）产品安全公司设计和生产的税票所具有的安全特征，与货币上印制的标识符十分类似。

The stamp, which was designed and produced by the Canadian Bank Note Company and SICPA Product Security, contains security features much like the identifiers stamped on money.

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本文研究了雷达目标识别过程中关于目标的编码、分类特征的提取与选择等问题。

A new method for extracting radar target pole features from its RCS is presented in this paper.

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