研究了圆柱腔体共振频率的测量方法,测试了新建立的声速实验系统,结果显示圆柱共鸣腔具有较高的信噪比,共振频率的测量不确定度小于5×10^-6.采用Ar气(99.999%)标定了声速共鸣腔的有效长度,不确定度为1.8×10^-5。开展了303~333K下CO2的气相声速实验研究,实验结果表明,当实验工质具有较高的纯度(〉99.995%)时,气相声速的测量精度优于0.01%。
The measurement method of the frequency of a cylindrical resonator was investigated with a result of high signal-to-noise performance. Experimental study was conducted with the uncertainty of the resonance frequency reduced to 5 ×10^-6. Argon was used to calibrate the length and the radius of the cylinder with the uncertainty of 1.8×10^-5. Speed of sound for CO2 was measured from 303 to 333 K with a relative uncertainty of 0.01% when the purity of the substances better than 99.995%.