研制了悬滴法表面张力实验系统,温度测量范围为283.15~323.15 K ,温度测量误差不超过±0.5 K .采用轮廓拟合法对表面张力进行计算,在VC++环境下分别用坐标轮换法和Nelder‐Mead单纯形法进行了编程实现.利用正庚烷和乙醇对实验系统进行校验,结果表明:2种物质的表面张力实验值与文献值偏差在±0.2mN·m -1以内,坐标轮换法和Nelder‐Mead单纯形法的计算结果一致。
A surface tension experiment system using full‐profile fitting pendent drop method was built .The system could work at temperatures ranging from 283 .15 to 323 .15 K and its uncertainty of temperature measurement was better than ± 0 .5 K .The full‐profile fitting was implemented with co‐ordinate alternation method and Nelder‐Mead simplex method with VC+ + .The surface tensions of n‐heptane and ethanol were measured with this system .The deviations between experimental data and literature data were less than 0 .2 mN · m -1 ,which proved the reliability and stability of the system . Besides ,the analysis of experimental data suggested that both coordinate alternation method and Nelder‐Mead simplex method had good convergence and the latter was more computationally efficient .