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Title: | 主動非對稱粒子在二維膜上的運動 Motion of Active Swimmer in Two-Dimensional Film |
Authors: | Tzu-Chung Lin 林子鈞 |
Advisor: | 江宏仁(Hong-Ren Jiang) |
Keyword: | 主動粒子,二維肥皂膜,逆向分支, Janus particles,two dimensional soap film,inverse cascade, |
Publication Year : | 2014 |
Degree: | 碩士 |
Abstract: | 近年來,主動粒子的研究越來越多,其原因不外乎希望可以藉由控制主動粒子的運動,以達到其他的功能如輸送藥物或自組裝。在過去主動粒子的相關研究裡,大部分都在探討不同材料的主動粒子其運動的特性以及機制,主要的重點還是在討論單顆粒子在本體溶液中的運動行為,並沒有在二維系統中有太多的討論,我們希望可以藉由觀察主動粒子在二維膜上的運動特性,能使主動粒子在不同層面上有更多的應用。
在這個實驗中,我們設立了一個二維流體的系統,並將大量的3μm聚苯乙烯粒子以及非對稱粒子分別放入不同尺寸的肥皂膜中,利用不同的方式對粒子輸入能量(包含不同的雙氧水濃度以及雷射加熱強度),並利用PIV的方式來分析粒子所形成的流場,希望可以藉由此實驗,能將微觀尺度下粒子的單一運動與巨觀尺度粒子的聯合運動做一個連結。 我們觀察到非對稱粒子所形成的主動流場,除了在流場速度不同之外,流場形式也會由絮亂而變的較具整體性,我們藉著觀察單顆粒子在二維膜上的運動試圖解釋此現象,發現粒子在二維膜上的擾動會比在本體溶液中來的大,此擾動的能量將會儲存在流體中使得主動粒子會有聯合運動的產生,另外我們也發現在特定的條件之下,主動粒子所形成的二維流場會有逆向分支的情況發生,在部分線段會滿足k^(-5/3)定律。 In recent years, research of active particles has been widely developed , but most of research is focus on the motion of single particle in bulk solution, we hope we can improve applications of active particles by observing the motion of particles on two dimensional film. In this experiment, we construct a two-dimensional flow model. We use square soap film with different sizes, put both 3μm PS (polystyrene) particles and 3μm PS-Pt Janus particles into the soap film and inject energy into the system by different ways (including different hydrogen peroxide concentration and laser power). We use the PIV (Particle image velocimetry ) method to calculated the flow field .Hope we can establish a relation between macroscale and microscale behavior of Janus particles. For Janus particles in hydrogen peroxide soap film, the average velocity magnitude of the active flow are more higher than passive flow, the pattern of active flow will change from irregular to regular. We try to find a possible explanation from observe the motion of single Janus particles on the soap film, and we found that the fluctuation of Janus particles son soap film is much bigger than the fluctuation in bulk solution, and the fluctuation will cause the collective motion of Janus particles. We also calculate the power spectra compare with the inverse-cascade theory , and inverse-cascade spectra has be found in some situation which satisfy the k^(-5/3) law. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/58591 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 應用力學研究所 |
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ntu-103-1.pdf Restricted Access | 6.75 MB | Adobe PDF |
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