完全轮廓法计算液体表面张力的改进

Full-profile fit pendent drop method for surface tension measurements

为了提高液体表面张力测量的准确性和稳定性,该文基于悬滴法中完全轮廓法计算原理,改进了二维寻优算法中变量初值的选取方法,并利用权重因子对变量误差函数进行了修正,减小了液滴轮廓偏离点对表面张力测量结果的影响。在温度为25℃,常压条件下,利用改进后的完全轮廓法对水和无水乙醇表面张力进行了测量,结果表明:改进后的完全轮廓法相比原完全轮廓法测量标准差减小了40%,充分证明改进后的完全轮廓法具有更好的测量重复性和稳定性。

The accuracy and stability of surface tension measurements are improved fitting the entire surface profile in the pendent drop method with an algorithm to determine the initial value for two-dimensional optimization. Moreover, the error function was modified by a weighting factor which reduced the influence of the droplet profile deviation point on the surface tension measurement. The full-profile fitting method was used to calculate the surface tension of water and ethanol at 25~C and atmosphere. The final results show the standard deviation was reduced by 40% compared with the previous method, which verifies the stability and repeatability of this full-profile fitting pendent drop method.