This can automatically check vision, optometry and axial length measurement without the participation of professionals.
这可以自动检查视力、验光和轴长测量,无需专业人员参与。
可汗学院Khan Academy Middle school physics - NGSS初中物理
I just used three examples of length measurements with three different units, inches, feet, and meters.
我刚刚使用了三个不同单位的长度测量示例:英寸、英尺和米。
英语百科
Length measurement
Length measurement is implemented in practice in many ways. The most commonly used approaches are the transit-time methods and the interferometer methods based upon the speed of light. For objects such as crystals and diffraction gratings, diffraction is used with X-rays and electron beams. Measurement techniques for three-dimensional structures very small in every dimension use specialized instruments such as ion microscopy coupled with intensive computer modeling.