By use of magnetic balance which is general physical experiment instrument, a simple and new method of measuring the charge-mass ratio of electron mass developed.
使用常用物理实验仪器磁天平，开发出用于近代物理实验测量电子荷质比的简易新方法。
2
An instrument with three wavelengths for measuring the extinction ratio of laser crystal is described.
介绍一种三波长的激光晶体消光比测试仪。
3
The instrument has two functions such as sample yarn winder and measuring reel. It also has the simple and compact structure and high performance price ratio which can reduce the test costs of users.