近年來微機電（MEMS）技術的蓬勃發展，將現代科技從巨觀之角度切入到微觀系統下來探討，並引發了微全分析系統（micro total analysis system）的研究，此系統具有體積小、檢測樣品少、反應時間快等優點。隨著檢測系統的簡化，在微小管道中以壓力驅動流體之微流體晶片則日趨重要。
在微流體晶片中，其尺度微小之關係使得流體在管道中有別於巨觀之流場特性，其中管道壁面效應為重要參數。在壁面效應的影響下造成流體阻力隨著表面積與體積比而改變，也就是流體阻力會因為管道之深寬比（aspect raio）不同使得微流場呈現不同之速度分佈特性。
本文中之理論探討是以Navier-Stokes Equation推導出適用於本研究之流阻公式，再以實驗來驗證此流阻公式在微觀流場之適用性。利用微影製程之二次光阻堆疊技術，建構出實驗設定之相同截面積（cross-section area）不同周邊長（perimeter）的尺寸參數，並且在實驗中建立一套系統來勾勒管道Z軸截面之速度分佈，以討論壁面效應對於流體阻力與流量變化之影響。
本研究中，用實驗驗證流阻公式在微管道中定性的可靠性，也證實了微管道中壁面效應對於流阻變化之影響。此結果加深我們對微流場特性的瞭解，並且做為未來利用流阻控制流量變化之一項依據。

Micro-Electro-Mechanical-System（MEMS）is developed rapidly in recent years, and it facilitates the study of micro total analysis system（μ-TAS）. The system offers several potential advantages. It needs very small volume of samples and reagents, produces little waste, and offers short reaction and analysis time. For simplifying the system, the pressure-driven microfluidic chip is important nowadays.
The properties of flows in microfluidic are different from that of the traditional fluid due to high surface to volume ratio. And the surface effect becomes an important parameter that will change the flow resistance in microchannels. In other words, aspect ratio in microchannels will affect the velocity distribution.
Analytically, we use Navier-Stokes Equation to derive the flow resistance formula and verify its suitability by experiment. In order to fabricate two sub-channels with different aspect ratio while maintaining the same cross-section area, we utilize photolithography fabrication process to coating photoresist twice on silicon wafer. We set up an experiment system to measure the velocity distribution along the Z-plane in microchannels, and the influence of surface effect on the flow resistance and flow rate in discussed.
This study has proved experimentally that the flow resistance formula is valid in microchannels. We also have verified surface effect on the change of flow resistance in microchannels.

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