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By the method of ray tracing , the glass beads retroreflective array flim has been studied in detail. 用光路分析的方法，詳細研究了玻璃微珠逆反射列陣膜的光學特性。
An abacus is essentially an array of beads threaded on string or held in grooves, with each row representing a different digit. 算盤實質(zhì)上是一串穿在線或者擺在凹槽里的珠子，每一列代表不同的數(shù)位。