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<專題討論>2017/5/4(四)14:30綜合大樓2樓48218教室演講「Effects of polarization-charge shielding in microwave heating」( 朱國瑞 院士 / 臺灣大學物理系)

張貼者:2017年4月28日 上午12:35Dabby Lu   [ 已更新 2017年4月28日 上午12:38 ]

“Heating of dielectric objects by radio frequency (RF) and microwaves has long been a method widely employed in scientific research and industrial applications. However, RF and microwave heating is often susceptible to an excessive temperature spread due to uneven energy deposition. The current study elucidates an important physical reason for this difficulty and proposes an effective remedy. Non-spherical samples are placed in an anechoic chamber, where it is irradiated by a traveling microwave wave with 99% intensity uniformity. Polarization charges induced on the samples tend to partially cancel the incident electric field and hence reduce the heating rate. The polarization-charge shielded heating rate is shown to be highly dependent on the sample’s shape and its orientation relative to the wave electric field. For samples with a relatively high permittivity, the resultant uneven heating can become a major cause for the excessive temperature spread. It is also demonstrated that a circularly-polarized wave, with its rapidly rotating electric field, can effectively even out the heating rate and hence the temperature spread.”

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Dabby Lu,
2017年4月28日 上午12:35
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