在频率50Hz~1MHz内,采用平行极板法研究从不同高度跌落并贮藏3d时红地球葡萄的介电参数变化规律。从同一高度跌落后,随加载频率增加红地球葡萄的复阻抗的模和并联等效电容值呈减小趋势,电导值呈增大趋势,损耗因子呈先减小后增大、品质因数呈先增大后减小趋势,且在25kHz时损耗因子和品质因数存在极值。在80~200 cm的跌落高度内,随跌落高度的增加红地球葡萄复阻抗的模和品质因数呈先增大后减小的趋势,电导、并联等效电容和损耗因子呈先减小后增大的趋势,且120 cm跌落时其复阻抗的模和品质因数最大,电导、并联等效电容和损耗因子最小。综合分析可知,通过葡萄介电参数的变化可反映其所受到的机械损伤程度,且其介电特性与电场频率有很强的相关性。

The changes of dielectric parameters of the grapes which were fallen from different heights and then stored for 3 days were studied by parallel plate capacitor in the rang of 50HZ-1MHZ.At the same fallen height,with the increase of electric conductance,the complex impedance module and equivalent capacitance decrease,electric conductance increase,the loss factor decreased first and then increased,quality factor increased first and then decreased with the frequency increased,and the loss factors and the quality factors were at extreme values at 25kHz.In the fallen range of 80 ~ 200cm,the grapes complex impedance module and quality factor increase first and then decrease and were at the maximum in 120cm,electric conductance,equivalent capacitance and loss factor decreased first and then increased and were at the minimum in 120cm.Overall,the mechanical damages of the grapes can be observed by dielectric parameters changes,and highly correlation between dielectric parameters and electric frequency was exist.