Temperature dependent dielectric of aqueous NaCl solution at microwave frequency
温度相关的微波频率下氯化钠水溶液介电特性

Dielectric properties of aqueous NaCl solution, which are dependent on temperature (293-353 K), with a concentration in a range of 0.001-0.5 mol/L at microwave frequencies ranging from 200 MHz to 6.25 GHz are studied experimentally. The results indicate that imaginary part decreases with frequency increasing, and tetrahedral structure of H2O and hydrogen bond of aqueous NaCl solution is broken by high temperature, leading to the decreasing of real part of dielectric. The loss angle tangent in solution obviously decreases in a low frequency zone at 353 K compared with that in pure water. Temperature window effect that complex dielectric increases or decreases with temperature varying at 2.45 GHz and 5.8 GHz, thereby leading to the oscillation of dissipation power in microwave heating process and the nonequilibrium distribution of temperature is also confirmed.