摘要
本文主旨是研究液珠於加熱盤上之振盪行為與物理現象，探討液珠體積、液珠振盪模式與頻率及液珠內部流場之關係，分析重力、浮力、表面張力、黏滯度等物理因子對於液珠振盪模態之影響，並依據研究結果提出簡易的「液珠熱能階振盪理論」。由於熱懸浮液珠底層的氣液界面具有類似蓮葉複合表面微結構之特性，因此本文亦探討了濱海植物表面複合微結構之疏水特性，希望作為仿生研發之參考。
本文藉由高速攝影機觀測並歸納液珠在受熱狀態下之振盪模式與輪廓變化，並以無因次化分析法整理出各種力效應的影響。在液珠振盪且呈現動態平衡的情形，根據泰勒不穩定理論和邊界層理論可以知道底層氣膜提供初始振盪的波動能量，振盪時黏滯力和重力兩者分別為(R,θ)方向和Z方向的主導力，對於振盪頻率及模態的影響很大。本文也使用粒子影像測速儀(PIV)量測液珠振盪時的速度場、渦度和流線，深入探討加熱盤上液珠之振盪行為與液珠內部流場關係。
為探討蓮葉效應的複合表面結構，本文量測黃瑾、馬鞍藤、海桐、林投、蔓荊和月桃等濱海植物葉片表面的接觸角，藉由SEM影像觀察到葉片表面結構有「革質」、和「星狀結構」，這些葉面皆屬疏水性質，具有自清及保護作用，未來可考慮解析結構及材質機能。

Abstract
The goal of this thesis is to investigate the oscillation behavior and physical mechanisms associated with a droplet placed on a heated plate. The correlations between volume, oscillation mode and frequency, and interior flow-fields of the droplet are revealed. The impacts of gravity, buoyant force, surface tension, and viscosity on the oscillation mode of the droplet are analyzed. A simplified theorem of “thermal-quantum oscillation of a droplet” is proposed. Due to the structural analogy of the vapor-liquid interface underneath the suspended droplet and the micro surface-structure of lotus leaves, this thesis studies as well the hydrophobic characteristics of the composite micro surface-structure of strand plants, so as to provide a reference for biomimetic applications.
Experimental analysis and observations were carried out to characterize the oscillation modes and deformation of the heated droplet. Dimensional analysis is employed to dissect the extent of impact of various forces acting on the droplet.
It is found that, on the bases of both the Taylor instability theory and the boundary layer theory, the energy for initializing the oscillation of the droplet sources from the gas-film within the vapor-liquid interface underneath the droplet. Viscous force and gravity force are respectively the dominant forces for the (R,θ) and Z- directions. In addition, the interior flow-fields of the oscillating droplet are quantitatively visualized by Particle Image Velocimetry, rendering the fluid velocities and vorticity. The correlations between the interior flow-fields and oscillation modes of the droplet are discussed.
In order to explore the lotus effect of composite surface structure of strand plants, the contact angle intrinsic to the leaves of (Hibiscus tiliaceus, Dracaena angustifolia, Ipomoea pes-caprae, Vitex rotundifolia L. f., Scaevola sericea, and Alpinia zerumbet) are measured. Employing SEM, “stellate trichome” and “leathery structure” are recognizable on the surface of those strand plants. It is discovered that the surface of those measured leaves of strand plants are almost hydrophobic, possessing the capabilities of self-clean and protection. Future studies may focus on physical properties of structures of those strand plants.

Adachi, K., and Takaki, R., “Vibration of a flattened drop I. Observation,” Journal of the Physical Society of Japan, vol. 53, pp.4184-4191, 1984.
Barthlott, W. and Neinhuis, C., “Purity of the sacred lotus, or escape from contamination inbiological surfaces,” Planta, vol. 202, pp. 1-8, 1997.
Berenson, P.J., “Film-boiling heat transfer from a horizontal surface,” J. Heat Transfer, vol.83, pp.351-358, 1961.
Bleiker, G. and Specht E., “Film evaporation of drops of different shape above a horizontal plate,” International Journal of Thermal Sciences, vol. 46, pp. 835-841, 2007.
Bojarevics, V., and Pericleous, K., “Droplet oscillations in high gradient static magnetic field,” Microgravity Science Technology, vol. 21, pp. 119-122, 2009.
Cassie, A. B. D. and Baxter, S., “Wettability of porous surfaces,” Transactions of the Faraday Society, vol. 40, pp. 546-551, 1944.
Chaves, H., Kubitzek, A. M., and Obermeier, F., “Dynamic processes occurring during the spreading of thin liquid films produced by drop impact on hot walls,” International Journal of Heat and Fluid Flow, vol. 20, pp.470-476, 1999.
Chen, J. H., Yang, J. T., Huang, K. J., Yu, C. S., and Hu, Y. C., “Droplet manipulation over a hydrophobic surface with roughness patterns,” ASME Heat Transfer/Fluid Engineering Summer Conference, Charlotte, N.C., July 11-15, 2004.
Cossali, G. E., Marengo, M., and Santini, M., “Thermally induced secondary drop atomization by single drop impact onto heated surfaces,” International Journal of Heat and Fluid Flow, vol. 29, pp. 167-177, 2008.
Extrand, C. W., “Model for contact angles and hysteresis on rough and ultraphobic surfaces,” Langmuir, vol. 18, pp. 7991-7999, 2002.
Jansson, T. R. N., Haspang, M. P., Jensen, K. H., Hersen, P., and Bohr, T., “Polygons on a rotating fluid surface,” Physical Review Letters, vol. 96, pp.174502, 2006.
John, N. A. Lott, A Scanning Electron Microscope：Study of Green Plants, Mosby, Saint Louis, 1976.
Johnson, R. E. and Dettre, R. H., “Contact angle hysteresis: contact angle measurements on rough surfaces,” Advances in Chemistry Series, pp. 112-144, 1963.
Jung, M. O., Sung, H. K., and Kwan, H. K., “Shape oscillation of a drop in ac electrowetting,” Langmuir, vol. 24, pp. 8379-8386, 2008.
Lai, M. F., Lee, C. P., Liao, C. N., and Wei, Z. H., “Oscillation spectrums and beat phenomenon of a water droplet driven by electrowetting,” Applied Physics Letters, vol. 94, 154102, 2009.
Lamb, H., Hydrodynamics, Dover.
Lin, D. Y.T., Westwater J.W.,” Effect of metal thermal properties on boiling curves obtained by the quenching Method,” Proceeding of 7th International Heat Transfer Conference, Munich, vol. 4, pp. 155-160.
Lord Rayleigh, “On the capillary phenomena of jets,” Proceedings of the Royal Society of London, vol.29, pp.71-97, 1879.
Miraghaie, R., Sterling, J. D., and Nadim A., “Shape oscillation and internal mixing in sessile liquid drops using electrowetting-on-dielectric (EWOD),” Nano Science and Technology Institue-Nanotech, vol. 2, pp. 610-613, 2006.
Okada, M., and Okada, M., “Observation of the shape of a water drop on an oscillating Teflon plate,” Experimental Fluids, vol. 41, pp. 789-802, 2006.
Perez, M., Brechet, Y., Salvo, L., Papoular, M., and Suery, M., “Oscillation of liquid drops under gravity: influence of shape on the resonance frenquency,” Europhysics Letter, vol. 47, pp.189-195, 1999.
Sakurai, A., Shiotsu, M., and Hata, K., “A General correlation for pool film boiling heat transfer from a horizontal cylinder to subcooled liquid,” Part1: A Theoretical Pool Film Boiling Heat Transfer Model Including Radiation Contribution and Its Analytical Solution,” Journal of Heat Transfer, vol. 112, pp. 430-440, 1990.
Takaki, R., and Adachi, K., “Vibration of a flattened drop II. Normal mode analysis,” Journal of the Physical Society of Japan, vol. 54, pp.2462-2469, 1985.
Takaki, R., Katsu, A., and Arai Y., “Vibration of a flattened drop III. Mechanism of mode transition,” Journal of the Physical Society of Japan, vol. 58, pp. 129-139, 1988.
Wenzel, R. N., “Resistance of solid surfaces to wetting by water,” Industrial and Engineering Chemistry, Vol. 28, pp. 988-994, 1936.
Yang, J. T., Chen, J. H., Huang, K. J., and Yeh, J. A., “Droplet manipulation over a hydrophobic surface with roughened pattern,” IEEE/ASME Journal of Microelectromechanical Systems, vol. 15, June, pp. 697-707, 2006.
Yao, S.C. and Henry, R.E., “ An Investigation of the minimum film boiling temperature on horizontal surfaces,” Journal of Heat Transfer, Trans. ASME, vol. 100, pp. 260-267, 1978.
Yoshiyasu, N., Adachi, K., and Takaki, R., “Effect of ambient temperature on the self-induced vibration of boiling drop,” Journal of the Physical Society of Japan, vol. 62, pp.2314-2323, 1993.
Yoshiyasu, N., Matsuda, K., and Takaki, R., “Self-induced vibration of a water drop placed on an oscillation plate,” Journal of the Physical Society of Japan, vol. 65, pp. 2068-2071, 1996.
Zuber, N., “On the Stability of Boiling Heat Transfer,” Trans. ASME, vol. 80, pp. 711-720, 1958.
李瑞宗, 植物地圖：台灣低海拔植物生態,國立自然科學博物館, pp. 38-40,96, 台中, 2000.
許慶文, 竹塹的海濱植物,新竹市立文化中心, pp. 10-14,34-36,43,60-63,72-73,88- 89, 136-51, 新竹,1998.
廖玉琬,植物生理學, 啟英文化事業有限公司, pp. 540-49,556-59, 台北, 1999.