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针对NaCl水溶液(0.001—0.5mol/L)介电特性,实验调查了频率(200—6.25GHz),温度(293—353K)、浓度相关复介电常数.结果表明:频率增大的过程中虚部呈逐渐减小的趋势,高温使离子扰动增大,破坏了溶液内部水分子四面体结构和氢键构象而使介电常数实部减小.与纯水相比,溶液的损耗角正切在高温353K低频区下降明显.同时发现2.45和5.8GHz的复介电常数随温度变化的温度窗效应,温度窗效应导致微波加热时耗散功率的振荡变化,温度分布不均匀现象在实验中得以证实.
Aiming at the dielectric properties of NaCl aqueous solution (0.001-0.5mol / L), the complex dielectric constant of frequency (200-6.25GHz), temperature (293-353K) and concentration were investigated.The results show that the process of increasing frequency Department of the trend of decreasing gradually, the high temperature causes the ion perturbation increases, undermines the tetrahedron structure and hydrogen bond conformation of the water molecules inside the solution and the real part of the dielectric constant decreases.With the pure water, the loss tangent of the solution is The low frequency region of 353K at high temperature dropped significantly.At the same time, the temperature window effect of the complex permittivity of 2.45 and 5.8 GHz with temperature was found, and the temperature window effect resulted in the oscillation variation of power dissipation during microwave heating. The uneven temperature distribution was confirmed in the experiment .