Abstract：As an important part of density standards, liquid density standard plays a significant role in quantity transfer and traceability. In order to correct the influence of pressure, a method is proposed to measure the compressibilities of density standard liquids at low pressure. The relationship between the density of liquid and pressure is established by a calibration measuring which device of pure water and air standard density. Compressibilities of density standard liquids were measured by vibrating-tube densimeter calibrated. According to the result, the relative change is about 1×10-6 in the density of the liquid caused by the elevation of 100 m, which verified the necessity of the correction.
［1］Fujii K. Present state of the solid and liquid density standards ［J］. Metrologia, 2004, 41:S1-S15.
［2］Fujii K. Precision density measurements of solid materials by hydrostatic weighing ［J］. Measurement Science & Technology, 2006, 17(10):2551-2559.
［3］Bettin H, Toth H. Solid density determination by the pressure-of-flotation method ［J］. Measurement Science & Technology, 2006, 17(10):2567-2573.
［4］Fehlauer H, Wolf H. Density reference liquids certified by the Physikalisch-Technische Bundesanstalt ［J］. Measurement Science & Technology, 2006, 17(10):2588-2592.
［5］罗志勇, 杨丽峰, 陈允昌. 基于多光束干涉原理的相移算法研究［J］. 物理学报, 2005, 54(7): 3051-3057.
［6］罗志勇. 单晶硅球密度的绝对测量［J］. 计量学报, 2012, 33(5):428-431.
［7］王金涛, 刘子勇. 基于静力悬浮原理的单晶硅球间微量密度差异精密测量方法研究［J］. 物理学报, 2013, 62(3): 374-381.
［8］WANG J T, LIU Z Y, XU C H, et al. Measurement method of compressibility and thermal expansion coefficients for density standard liquid at 2329 kg/m3 based on hydrostatic suspension principle ［J］. Chinese Journal of Mechanical Engineering, 2014, 27(4):779-784.
［9］崔英伟, 孙坤, 刘振兴. 油液体积弹性模量的测量［J］. 液压气动与密封, 2012, 32(3):17-19.
［10］Pena M D, Tardajos G. Isothermal compressibilities of n-alkanes and benzene ［J］. Journal of Chemical Thermodynamics, 1978, 10(1): 19-24.
［11］Picard A, Davis R S, Glser M, et al. Revised formula for the density of moist air (CIPM-2007)［J］. Metrologia, 2008, 45(2):149-155.
［12］Sanmamed Y A, Dopazo-Paz A, González-Salgado D, et al. An accurate calibration method for high pressure vibrating tube densimeters in the density interval (700 to 1600) kg· m 3［J］. Journal of Chemical Thermodynamics, 2009, 41(9):1060-1068.
［13］YIN J, WU J, MENG X, et al. Compressed liquid density measurements of dimethyl ether with a vibrating tube densimeter ［J］. Journal of Chemical Thermodynamics. 2011, 43(9):1371-1374.
［14］Tanaka M, Girard G, Davis R, et al. Recommended table for the density of water between 0 °C and 40 °C based on recent experimental reports［J］. Metrologia, 2001, 38(4):301-309.
［15］文晓林, 何家骏. 二组分系统的压缩系数和热压力系数［J］. 物理化学学报, 1992, 8(6): 804-808.
［16］李之昊, 王金涛, 刘翔, 等. 基于Karl Fischer电位滴定原理的超微量液体容积精密测量方法［J］. 计量学报, 2017, 38(3): 296-299.
［17］Aicart E, Tardajos G, Pea M D. Isothermal compressibility of cyclohexane + n-tridecane and + n-pentadecane at 298.15, 308.15, 318.15, and 333.15 K［J］. Journal of Chemical Thermodynamics, 1981, 13(8):783-788.
［18］Fehlauer H, Wolf H. Density reference liquids certified by the Physikalisch-Technische Bundesanstalt［J］. Measurement Science & Technology, 2006, 17(10):2588-2592.
2018, Vol. 39 
