Zhongyou Liu

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Instead of the traditional heating method, the cavity length of an internal-mirror He-Ne laser is controlled by air cooling which is implemented by a mini cooling fan. The responsive property of the cooling fan and the thermal expansion of the internal-mirror laser tube are investigated. According to these investigations, a controlling system is designed to(More)
A direct phase coherent determination of the absolute frequency of the a15 component in the R(12) 26-0 and b10 component in the R(106) 28-0 transitions in I2 at 543 nm has been made at the International Bureau of Weights and Measures. Lasers from the Czech Metrology Institute (Czech Republic), the National Institute of Metrology (China), the Centro Nacional(More)
A new type of calculable capacitor was initially built at the National Institute of Metrology, China, in cooperation with the National Measurement Institute, Australia. The capacitor realized the SI unit of capacitance at 1 pF, with an uncertainty of 20 parts in 109. A simplified operational approach was used that avoids the complex substitution measuring(More)
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