差示扫描量热基线漂移补偿算法设计

Design of baseline drift compensation algorithms of differential scanning calorimetry

差示扫描量热分析是测量材料热物性的重要方法,根据其测量原理,传感器上样品与参比端差式输出的基线漂移将严重降低测量精度和范围.在仪器实际制造过程中,由于加工工艺水平和材料纯度等因素的影响,基线漂移不可避免,因此必须对其进行补偿.我们利用FIR等波纹逼近的方法对基线信号进行低通滤波去除带外杂波,并基于热流传感器的数学模型提出了一种扣除热流传感器中样品端与参比端热阻和热容不平衡影响的基线漂移补偿算法.实验表明,该算法可将基线的漂移量由-99.03～0.42μW降低到-1.32～1.25μW,证明了算法的有效性.

Differential scanning calorimetry is an important method of material＇s thermal properties test.The baseline drift of the heat-flux sensors between the sample and the reference endpoints will seriously deteriorate the accuracy and the range of measurement.Since the drift was inevitable in actual manufacturing processes because of the effects of the processing techniques and the purity of the materials,it was necessary to compensate.An algorithm based on the mathematical model of the heat flow sensors by using a low-pass equal-ripple FIR filter to smooth out the out-of-band noises and to reduce the impact of the unbalanced resistances and capacities between the sample and reference endpoints was proposed for the compensation of the baseline drift.The test results showed that it can effectively reduce the baseline drift from-99.03～0.42 μW to less than-1.32～1.25μW.