This paper studies the establishment of four-mirror circle feedback system and the principle of controllingcontrast changes of the image pattern by this system.
本文讨论了建立四反射镜环形反馈系统的有关问题，探讨了利用环形反馈系统控制图象对比度变化的原理。
2
In contrast, China's impressive success in controlling malaria has at least one historical reason.
相比之下，中国在疟疾控制方面取得的重大成就至少有一点历史原因。
3
The scanning converter supplies two communicative ways:RS-422 and RS-232. Through these ways the main controlling system controls the brightness, contrast, saturation of output pictures.