双光镜
- 网络bifocal lenses;univis
双光镜-
论熔合双光镜最小中心厚度的计算方法
Calculation of minimum central thickness of fused - bifocals
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偶尔有内斜视的孩子会需要双光镜来控制内斜。
Occasionally , children who have crossed eyes may need to have bifocals to help control the crossing .
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1977年我们继续对Sco-Oph区进行联合照相观测.使用北京天文台施密特镜和紫金山天文台及北京天文台的双筒拆光镜。
In 1977 , we continued our cooperative observations in the Sco-Oph region with the Schmidt telescope of the Beijing Observatory and the double astrographs of the Purple Mountain Observatory and the Beijing Observatory .