铝材灯饰零件对镀层光亮度和结合力有着比较高的要求，采用电镀加工方法废品率高。
The excellent brightness and cohesion of the plating layer are needed for aluminium lamp finishing parts.
本文提出一种新方法——密度矩和法，用底片上已知亮度恒星的PDS测微密度数据来同时决定底片特性曲线和星等零点。
A new method is suggested for determining the characteristic curve of a plate, as well as the magnitude zero point, using PDS microdensitometer data of stars of known brightness on the plate.
这颗星星因为亮度变化比一般星星的变化间隔时间要长。周期持续整整2天零20个小时零49分钟。
This star is known to vary in brightness over a regular time interval. The cycle lasts exactly 2 days, 20 hours and 49 minutes.
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