桃果实电特性的频率变化

Influence of Frequency Signal on Electrical Property of Peach Fruits

以‘秦光2号’油桃为测试对象,研究果实电参数的频率特性。测定不同频率下桃果实14个电参数值,用SPSS软件分析并拟合果实的随频率变化的函数方程(相关性都达显著水平)。结果表明:除了品质因子(Q)随频率变化无规律,其余13个电参数都随频率呈有规律的变化(是电激励频率的函数),其中复阻抗(Z)、串联等效电阻(Rs)、并联等效电阻(Rp)、电抗(X)随电激励频率变化呈三次函数下降变化;串联等效电容(Cs)、并联等效电容(Cp)随频率变化规律相似,阻抗相角(θ)随频率呈U型变化,损耗系数(D)随频率呈W型变化;导纳(Y)、电纳(B)、串联等效电感(Ls)、并联等效电感(Lp)、电导(G),随电激励频率呈指数上升变化。

The purpose of this study was to examine the effect of frequency on electrical parameters of peach fruits. The electrical impedance properties of nectarine ＇Qinguang 2＇, including fourteen electrical parameters, were investigated using HIOKI 3532-50 LCR HiTester. Nonlinear curve fitting using SPSS resulted in the establishment of mathematical models which depict the quantitative relationships between these parameters and frequency. All these parameters with the exception of Q factor presented regular changes with increasing frequency while an inverse cubic correlation with frequency was observed on impedance （Z）, equivalent serial resistance （Rs）, equivalent parallel resistance （Rp） and reactance （X）. Equivalent serial capacity （Cs） showed a similar pattern to that of equivalent parallel capacity （Cp）.The change in impedance phase angle （0） with frequency was a U-shaped curve while a W-shaped curve was observed for loss coefficient （D）. Electrical excitation frequency admittance （Y）, susceptance （B）, equivalent series inductance （Ls）, parallel equivalent inductance （Lp） and conductance （G） presented an exponential increase with excitation frequency.