【作者】 郭文川； 吴晓玲； 朱新华； 王绍金；

【Author】 Guo Wenchuan1,Wu Xiaoling1,Zhu Xinhua1,Wang Shaojin1,2(1.College of Mechanical and Electronic Engineering,Northwest A&F University,Yangling,Shaanxi 712100,China 2.Washington State University,Department of Biological Systems Engineering,Pullman,WA,USA,99164-6120)

【机构】 西北农林科技大学机械与电子工程学院； Washington State University,Department of Biological Systems Engineering,Pullman,WA；

【摘要】 用同轴探头和网络分析仪测量了20～60℃和10～4500MHz下板栗和栗实像甲的介电特性。研究结果表明,二者的相对介电常数ε’随着频率的增大而减小。频率小于3000MHz时,板栗的介质损耗因数ε’’随频率的增大而减小,大于3000MHz时有轻微的增大。栗实像甲的ε’’随频率的增大而减小,在1000MHz达到最小值。频率小于此拐点时,ε’’随温度的增大而增大,而在拐点以上随温度减小。板栗和栗实像甲的ε’和ε’’都随着温度的增大而增大,穿透深度随着频率或温度的增大而减小。低频下较大的介质损耗因数差异和足够的穿透深度,使得利用100MHz以下的射频能进行介电加热灭杀栗实像甲成为可能。更多还原

【Abstract】 The dielectric properties of chestnut and chestnut weevil at five temperatures between 20 oC and 60 oC over the frequency range from 10 to 4500 MHz were measured with an open-ended coaxial-line probe and network analyzer.The dielectric constants ε ’ of both materials decreased with increasing frequency.The ε ’’ of chestnut decreased with increasing frequency below about 3000 MHz,and had a slight increase above 3000 MHz.The ε ’’of chestnut weevil decreased with increasing frequency to a minimum value at about 1000 MHz.Below the turn point,the value of ε ’’ increased with increasing temperature,and decreased with temperature above that point.The ε ’ and ε ’’of chestnut and ε ’ of chestnut weevil increased with increasing temperature.The penetration depth decreased with the increase of either frequency or temperature.Dielectric heating below 100 MHz might provide practical applications in controlling chestnut weevil due to potential differential heating and sufficient penetration depth.The study offers useful information on dielectric properties of chestnut and chestnut weevil in developing thermal treatments for postharvest disinfestation based on electromagnetic energy.更多还原