竹材介电性质研究

Study on Dielectric Properties of Bamboo Culm

研究了毛竹不同部位、竹龄、纹理、含水率和测试频率对介电常数和介质损耗角的影响。结果表明:在纤维饱和点以下,介电常数随着含水率的增大而增加缓慢,在纤维饱和点附近,介电常数随着含水率的增加而急剧增加,高于纤维饱和点后,介电常数和含水率成近似线性关系;纵向介电常数大于径向和弦向介电常数,径向介电常数和弦向介电常数间差异不显著;频率低于6 kHz时,介电常数随着着频率的增大减小明显,频率高于6 kHz后,介电常数随着频率的增加变化缓慢;竹龄、部位因素对竹材介电性能的影响规律不显著。

Determination was conducted on dielectric constant and loss of bamboo （Phyllostachys heterocycla cv. pebescens） culm. The result demonstrated that dielectric constant increased slowly with the moisture content below fiber saturation point （FSP）, increased sharply with the moisture content around the FSP, and when above the FSP, it had a linear relation with the moisture content. Dielectric constant of grain direction was higher than that of other two directions. It decreased obviously with the increase of frequency, but changed slowly when it above 6 kHz. Culm age, different part of culm had no evident effect on dielectric constant.