DC 欄位 值 語言 DC.contributor 物理學系 zh_TW DC.creator 吳冠廷 zh_TW DC.creator Kuan-Ting Wu en_US dc.date.accessioned 2017-1-19T07:39:07Z dc.date.available 2017-1-19T07:39:07Z dc.date.issued 2017 dc.identifier.uri http://ir.lib.ncu.edu.tw:88/thesis/view_etd.asp?URN=104222029 dc.contributor.department 物理學系 zh_TW DC.description 國立中央大學 zh_TW DC.description National Central University en_US dc.description.abstract 本研究專注於微小游泳粒子(細菌)在固定表面的聚集現象。浮游微生物在表面群聚並附著會形成生物薄膜，密切的影響著人類。常見於牙齒、杯壁和傷口等表面。且可能進一步在輸水管線內部、船殼表面造成生物淤積。雖然已經有許多清除的方法，現今的科學家投入更多的關注於微小游泳粒子與固定表面之間的交互作用，以預防生物薄膜的形成。 過去的研究發現，在低雷諾數的狀況下，會游泳的微小的細胞或細菌，如大腸桿菌、新月柄桿菌和精蟲，在黏著於表面之前都容易在固定表面附近徘徊、聚集。已經有許多的實驗證明其中有一些相同的物理機制能夠影響游泳粒子在表面附近的行為，並使其不易游離表面。其中包含微小游泳粒子與固定表面的遠場流體力學、近場流體力學和碰撞交互作用，以及粒子本身的旋轉布朗運動。希望藉由本次研究進一步了解各種交互作用所扮演的角色，以及其實質貢獻。 我們分別運用三種不同游泳模式的單鞭毛溶藻弧菌Vibrio. Alginolyticus，Pusher、Puller和bimodal，觀察細菌在表面的游泳軌跡，以及距離表面20μm以內的細菌分佈。此種細菌的游速可由溶液中的鈉離子濃度調整，利於操控細菌與表面的遠場流體力學交互作用強度。實驗結果顯示細菌在表面游泳時的傾角決定其徘徊於表面機率。而其傾角則取決於近、遠場流體力學交互作用之間的競爭或加成。最後，我們亦能了解野生細菌如何利用游泳模式的轉換在不同的環境下維持其在表面的聚集。 zh_TW dc.description.abstract Microbial processes including biofilm formation or bio-fouling are ubiquitous and influence human extensively from daily lives to various industrial systems. For decades, researchers studied the processes and strategies of bacteria accumulation on surfaces. Considering the initial stage of biofilm formation, before the cell adhesion, swimming cells were reported swim along the surface for a long time. To describe the phenomenon, models of different perspectives of physics had been established, including far and near field hydrodynamic, steric effects and diffusion. To reach a more complete picture for the cell-surface interaction, we manipulated the swimming characteristic of single polar-flagellated bacteria, Vibrio. Alginolyticus, with mutant strains at different swimming speed. Observing the steady-state bacteria distribution within 20μm from a surface, contributions of each mechanism can be evaluated. Our results show that surface accumulation of microswimmers depends on both swimming speed and swimming characteristic. Accumulation of pusher bacteria is reduced as the speed increases. In contrast, accumulation of puller bacteria increases strongly with the speed. None of a previous model can fully explain our observations. By a closer look, the contribution of each mechanisms are assigned. Finally, we show that a microswimmer in nature can accumulate near a surface by a run and reverse swimming characteristic. en_US DC.subject 細菌 zh_TW DC.subject 表面 zh_TW DC.subject 低雷諾數 zh_TW DC.subject 自我推進粒子 zh_TW DC.subject 生物薄膜 zh_TW DC.subject microswimmer en_US DC.subject surface en_US DC.subject accumulation en_US DC.subject entrapment en_US DC.subject low Reynolds number en_US DC.subject bio-film en_US DC.title 微小游泳粒子在固定表面的聚集現象 zh_TW dc.language.iso zh-TW zh-TW DC.title Accumulation of microswimmers near a no-slip surface en_US DC.type 博碩士論文 zh_TW DC.type thesis en_US DC.publisher National Central University en_US