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主旨 第二週碩博專討演講公告(3/14)
公告日期 2019-03-10
公告內容

碩博專題演講公告

題  目:Non-Fourier Thermal Conduction
講  者:張之威
現  職:台大凝態中心 副研究員

學  歷:UC Berkeley 博士

摘  要:

Fourier’s law of thermal conduction is perhaps the last empirical law of physics whose foundation is still not clear to us. Starting from 1930s’, many people have tried to derive Fourier’s law from statistical mechanics but the criteria of the Fourier’s law still remain unknown. In this seminar, I will present our experimental works starting to shred lights on the phenomena of non-Fourier thermal conduction in SiGe nanowires and in carbon nanotubes. For SiGe nanowires, we discover unprecedented robust ballistic thermal conduction persisting over 8.3 micrometers at room temperature, leading to non-conventional contact thermal resistance and non-additive thermal resistance in series. For ultralong carbon nanotubes, we find that their thermal conductivities increase with their lengths without signs of saturation and reach an unprecedented high value at room temperature for millimeter-long nanotubes. Our results suggest that the overlooked contributions of low frequency phonons are the possible origins for these unusual phenomena.

  1. K. Hsiao, et al, "Observation of room temperature ballistic thermal conduction persisting over 8.3μm in SiGe nanowires". Nature Nanotech. 8, 534 (2013).

V. Lee, et al, "Divergent and ultrahigh thermal conductivity in millimeter-long nanotubes", Phys. Rev. Lett. 118, 135901 (2017).

 

時  間:民國 108 年 3 月 14 日 下午 3:10

地  點:成功大學成功校區測量系一樓經緯廳

 

歡迎參加!!

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最後修改時間 2019-03-10 19:01:38