This paper highlights the influence of contact line (pinning) forces on the mobility of dry bubblesin microchannels. Bubbles moving at velocities less than the dewetting velocity of liquid on thesurface are essentially dry, meaning that there is no thin liquid film around the bubbles. For these“dry” bubbles, contact line forces and a possible capillary pressure gradient induced by pinningact on the bubbles and resist motion. Without sufficient driving force (e.g. external pressure) adry bubble is brought to stagnation. For the first time, a bipartite theoretical model that estimatesthe required pressure difference across the length of stagnant bubbles with concave and convexback interfaces to overcome the contact line forces and stimulate motion is proposed. To validateour theory, the pressure required to move a single dry bubble in square microchannels exhibitingcontact angle hysteresis has been measured. The working fluid was deionized water. Theexperiments have been conducted on coated glass channels with different surfacehydrophilicities that resulted in concave and convex back interfaces for the bubbles. Theexperimental results were in agreement with the model’s predictions for square channels. Thepredictions of the concave and convex back models were within 19% and 27% of theexperimental measurements, respectively.
聚乙烯(PE)管道具有优异的化学稳定性,无毒,室温下耐盐酸、氟酸、磷酸、甲酸、胺类、氢氧化钾、氢氧化钠等各种化学物质。聚乙烯管道柔而韧且轻便,并且耐磨损性强,被广泛应用于生活中的各个领域如石油、化工、供水、排水、天然气等领域。一、热老化用途热老化试验主要用于评估 PE 塑料管道在高温环境下的性能变化,包括材料的热稳定性、老化速率、机械性能等方面。通过对样品进行长时间的高温暴露,可以模拟实际使用环境中的热应力对管道材料的影响。
Bio-Monolith Protein A 色谱柱经过微小修饰减少了堵塞,极少或没有出现宿主细胞蛋白的非特异性结合。这些色谱柱表现出极小的残留和出色的使用寿命,即使在进样 750 次细胞培养上清液原液后,峰形也几乎没有变差。这为快速、准确地测定抗体滴度水平提供了出色的工具,适用于一次筛选数百个样品。