當氣體流經具有微米特徵尺寸的微流道時，即使其出口條件為一大氣壓，也將會因為流體分子與固體邊界的動量交換不完全而形成滑移流，為了研究切線動量修正係數與滑移流之間的關係，往往需要藉由量測微流道出口的質量流率來反推算出切線動量修正係數，但是流經微流道所產生的質量流率是相當小的，市售的流量計並無法精確的量測到如此小的流率，因此建構一個精確的量測系統是必須，在本實驗中，建構一個雙槽累積系統來做為量測微小流率的系統，其具有的優點為即使在一大氣壓的條件下也能準確量測到極小的流率所造成的 $130$ 帕斯卡大小的差壓，以及抑制量測系統對環境溫度的靈敏性。

微流道通常是藉由微機電製程所製造的，所以在製程選擇的差異以及晶片受汙染程度的大小，甚至儀器的優劣往往使得微流道內的表面粗糙度大相逕庭，而表面粗糙度卻是影響切線動量係數的重要參數之一，在 Arkilic 的實驗之中，雖然利用製程的選擇上製作出表面粗糙度僅 $0.75$ 奈米的光滑微流道，並研究氣體於其內所產生的滑移流現象，但是若是在不同的表面粗糙度下，必定會產生不同的結果，但是表面粗糙度是在製程的過程當中必然會產生的結果，故我們利用微機電製程在微流道內建構人工表面粗糙度，使得主要的表面粗糙度是經由人為所控制的，隨後再使用經過重新設計以避免漏電流產生的陽極鍵結系統對微流道晶片進行氣密封裝，以利後續量測實驗的進行。

至今，雙槽累積量測系統已建構完成，並已完成初步的測試，希望將來能藉由實驗中所建構的雙槽累積系統在相同的壓力條件作用下，量測具有不同表面粗糙度的流道所產生出來的質量流率，並反推算出其切線動量係數，以幫助我們更進一步的了解切線動量修正係數與表面粗糙度之間的關連性。

Due to the insufficient momentum exchange between the gas molecules and solid boundary, slip flow phenomenon may be observed when gas flows through microchannels with characteristic length scale of a few microns even at atmospheric pressure. Experimentally, the tangential momentum accommodation coefficient characterizing the slip flow has to be inferred from the macroscopic relationship between the mass flow rate and the pressure difference at the two ends of microchannel. This minute mass flow rate, however, can not be measured by commercially available flow meters. Consequently, construction of an accurate flow rate measurement system is essential to the study of slip flow phenomena in the microchannels. In this work, a dual-tank accumulation system capable of measuring mass flow rate at 10-7 mole/s was constructed. Sensitivity of the system to the ambient temperature fluctuation is suppressed and minute mass flowrate can be determined accurately even under atmospheric pressure.

In Arkilic's work, the tangential momentum accommodation coefficient of a smooth channel (surface roughness less than 0.75 nm) has been studied. However, surface conditions of the microchannels produced by microfabrication techniques are hardly smooth and these channels are usually built with some irregular structures for particular functions. Consequently, it will be interesting to investigate the slip flows in microchannels with some artificial roughness/structures. In this work, microchannels with prescribed artificial roughness were also constructed and hermetically sealed by the anodic bonding technology for the purpose of testing the constructed system.

Currently, the dual-tank accumulation system has been successfully constructed and tested. This system will be used to characterize the tangential momentum accommodation coefficients of microchannels with embedded artificial roughness in the near future. Hopefully, this will help us understand the slip flow phenomena in more realistic microchannels clearly.

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