Nelson Stuart O
U.S. Department of Agriculture, Agricultural Research Service, Richard B. Russell Agricultural Research Center, Athens, Georgia 30604-5677, USA.
J Microw Power Electromagn Energy. 2004;39(2):75-85. doi: 10.1080/08327823.2004.11688510.
A brief account of interest in dielectric properties of agricultural materials is presented, and some examples of dielectric spectroscopy applied to agricultural problems are discussed. Included are wide frequency range (250 Hz to 12 GHz) permittivity, or dielectric properties, measurements on adult rice weevils and hard red winter wheat, for the purpose of assessing selective dielectric heating of the insects, and broadband (200 MHz to 20 GHz) permittivity measurements on tissues of fresh fruits and vegetables. Similar measurements are shown for tree-ripened peaches, which were obtained to assess possibilities for a permittivity-based maturity index. Broadband (10 MHz to 1.8 GHz) permittivity measurements are shown for several fruits and vegetables as a function of temperature from 5 to 95 degrees C. Measurements over the same frequency range and similar temperature ranges are presented for two other food products, whey protein gel and apple juice. A few comments are offered on likely future dielectric spectroscopy applications in agriculture.
本文简要介绍了对农产品介电特性的研究兴趣，并讨论了一些将介电谱应用于农业问题的实例。其中包括对成年米象和硬红冬小麦在宽频率范围（250赫兹至12吉赫兹）的介电常数或介电特性测量，目的是评估昆虫的选择性介电加热，以及对新鲜水果和蔬菜组织的宽带（200兆赫兹至20吉赫兹）介电常数测量。还展示了对树上成熟桃子的类似测量结果，这些测量是为了评估基于介电常数的成熟度指标的可能性。展示了几种水果和蔬菜在5至95摄氏度温度范围内，宽带（10兆赫兹至1.8吉赫兹）介电常数随温度变化的测量结果。还给出了另外两种食品——乳清蛋白凝胶和苹果汁在相同频率范围和类似温度范围内的测量结果。最后对未来介电谱在农业中的可能应用作了一些评论。
