微波防治蟲害之新穎途徑與物理通則探討

Studies on a novel approach and physics of microwave insect pest control

蔡有方(Yu-Fang Tsai)

指導教授 ： 柯俊成 ； 朱國瑞

國立臺灣大學/生物資源暨農學院/昆蟲學研究所/博士(2019年)

https://doi.org/10.6342/NTU201903712

摘要

昆蟲危害會對儲物的品質和數量造成很嚴重的影響。利用極端的溫度殺死害蟲是最常見的物理防治法，而介電加熱到昆蟲的致死溫度是其中最快速的方式。雖經過往昔數十年研究，目前的技術仍亟待改進，我們乃對此議題進行更深入的物理通則探討，並提出一創新途徑。我們建立一套24 GHz加熱系統，此頻率遠高於往昔研究所使用之頻率，但仍屬科學、工業及醫療之使用頻段。微波源為千瓦級連續波分布作用震盪器，可穩定輸出可調整的微波。我們建立的微波暗室加熱系統也能應用於其他需要均勻加熱、可控制且能解析的微波研究。我們比較27 MHz、2.45 GHz、24 GHz發現，數據的準確度與電場均勻度呈正相關，與加熱時間呈負相關，顯示使用24 GHz高頻微波加熱並將樣本置於微波暗室內最能夠均勻且快速加熱。我們也研究在均勻電場下，微波加熱時產生不同溫度分布的內在成因。在均勻電場下，加熱的物體溫度具有25.2% 的差異，其最主要原因為極化電荷的屏蔽效應造成，單此效應即佔前述25.2% 中的18.2%。我們發現另加熱物體的形狀和介電損耗分別對不均勻溫度具有3.4% 和3.6%的加成。我們也以24 GHz達成差溫加熱，並研究害蟲與寄主差溫加熱效應中的科學議題。我們認為24 GHz高頻微波，以圓極化波加熱均勻且快速，具有極高的應用潛力。

關鍵字

微波加熱 ； 害蟲防治 ； 24 GHz ； 圓極化波 ； 差溫加熱

並列摘要

Insect pest infestation can cause severe quantity and quality losses to stored-agricultural products. Control insect pests with extreme temperatures are the mainstream physical treatments, dielectric heating insect to the lethal temperature is the fastest approach amongst all. For more demanding applications, current techniques need to be refined, which in turn requires a deeper understanding of the scientific issues involved, and a novel, fundamentally different approach. We built a microwave applicator for uniform irradiation of small samples at the relatively high, and rarely exploited, ISM frequency of 24 GHz. The radiation source is a 1 kW CW EIO with stable and variable output power. This type of applicator may also be a suitable tool for microwave-assisted research for which irradiation uniformity, controllability, and in situ diagnostics are desired. Among the comparison with 27 MHz, 2.45 GHz, and 24 GHz, the accuracy of data increases with more uniform field distribution and shorter heating time. suggests an anechoic chamber and circularly-polarized, 24-GHz microwave heats most fast and uniform. We also studied the inherent causes of percentage temperature spread in microwave heating. The percentage temperature spread due to all causes is measured to be at a high value of 25.2%, the dominant contribution is identified to be the polarization-charge shielding, which accounts for a percentage spread of ~18.2% relative to the overall value of 25.2%. Two other causes, sample shape and dielectric loss variations, each contribute to a percentage spread of ~3.4% and ~3.6%. We also demonstrate and study the scientific issues in differential heating. We suggest that high frequency such as 24-GHz heating with circularly-polarized wave shows great promising.

並列關鍵字

microwave heating ； insect control ； 24 GHz ； circular polarized wave ； differential heating

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