Foster K R, Schepps J L, Epstein B R
Bioelectromagnetics. 1982;3(1):29-43. doi: 10.1002/bem.2250030108.
We summarize the results of several of our recent studies on the dielectric properties of protein solutions, tissues, and nonionic microemulsions at microwave frequencies extending to 18 GHz. The data in all cases are analyzed using the Maxwell mixture theory to determine the dielectric properties of the suspending water and the amount and dielectric properties of the water hydration associated with the suspended phase. The dielectric data from the protein solutions and tissues are broadly consistent with the results of previous studies at UHF frequencies; they indicate hydration values in the range of 0.4-0.6 g water/g protein. There is evidence of a dielectric relaxation process occurring at low-GHz frequencies that can be attributed in part to dielectric relaxation of the "bound" water in the system. The remaining solvent water appears to have dielectric properties close to, if not precisely the same as, those of pure water. The average relaxation frequency of the suspending water in the microemulsions is reduced from that of pure water, evidently reflecting an average of that of the water of hydration (approximately 5-6 GHz) and that of pure water. This reduced average relaxation frequency implies an increased average viscosity of the water and (by Walden's rule) accounts for the unexpectedly low ionic conductivity of the preparations.
我们总结了近期几项关于蛋白质溶液、组织和非离子微乳液在高达18GHz微波频率下介电特性的研究结果。在所有情况下，均使用麦克斯韦混合理论对数据进行分析，以确定悬浮水的介电特性以及与悬浮相相关的水合水量和水合介电特性。蛋白质溶液和组织的介电数据与之前超高频频率下的研究结果大致一致；它们表明水合值在0.4 - 0.6克水/克蛋白质范围内。有证据表明在低GHz频率下发生了介电弛豫过程，这部分可归因于系统中“结合”水的介电弛豫。其余的溶剂水似乎具有与纯水相近（即便不完全相同）的介电特性。微乳液中悬浮水的平均弛豫频率低于纯水，这显然反映了水合水（约5 - 6GHz）和纯水弛豫频率的平均值。这种降低的平均弛豫频率意味着水的平均粘度增加，并且（根据瓦尔登规则）解释了制剂中离子电导率意外较低的原因。
