淮山药黏液稳定性与黏弹响应的关系

研究了淮山药黏液稳定性与黏弹响应的关系,发现在测试频率范围内,储能模量(G)始终大于损耗模量(G″),且均随频率变化不大,呈现出较强的网络结构特征,黏液性质对频率不敏感。黏液的表观黏度(a)与剪切速率(■)的关系可用Carreau模型较好地拟合,增大,黏液发生剪切变稀现象,表明黏液性质对剪切速率的变化较敏感;黏液的增比黏度(ηsp)与浓度(c)的关系为ηsp∝c3.01±0.12,黏液处于亚浓缠结区域。此外,盐度对黏液的黏弹响应影响较大,盐度增加,蛋白质分子间的静电排斥作用被屏蔽,分子间缠结增强,黏液的储能模量、损耗模量以及复数黏度(η*)逐渐上升,对黏液稳定性有一定影响。

Calculation of Random Response Spectral Moments of Elastic-viscoelastic Combined Systems

In random vibration analysis, the importance of spectral moments of the response stems from their relevance to system performance prediction. Usually,spectral moments are obtained by the frequency domain method. In present paper, the random response spectral moments of elastic-viscoelastic combined systems are calculated by complex modal analysis in the time domain. The analytical form results are obtained for random response spectral moments of an elastic-viscoelastic combined system to a stationary white noise excitation. The method presented is simple and easy to apply. It is hoped that this study would pave a way for the analysis of reliability of elastic-viscoelastic combined systems subjected to random excitations.