Gradient Generation from Devices

Fig. 5 Illustration of NIST Gradient UV-Ozone device for generating surface energy libraries on substrates functionalized with hydrophobic SAM species. The sample stage accelerates the specimen blue) beneath a slit-source of UV light. (Reproduced with permission from [12])...

The outlet from the mixing chamber of the gradient generator may be led into a device such as that of Caton and Goldstein (1971), ( 8.3.4.1), or by way of a manifold into the tubes individually. Mirault and Scherrer, on the assumption that the polymerisation velocity is proportional to the acrylamide concentration on the one hand, and that of TEMED and persulfate on the other, arranged that both the latter components were added at a concentration inversely proportional to that of the acrylamide (e.g. for 10 ml of 2% acrylamide 50 pi each of 10% TEMED and 10% persulfate were added, but for 10 ml of 6% acrylamide 16.7 p only of each). The gels were prepared at room temperature but the acrylamide... 

Fig. 3 Schematic of the mobile-phase gradient generation device based on electro-osmotic mixing of two liquids. (Reprinted with permission from C. Yan, R. Dadoo, R. N. Zare,...

Fig. 13.3 Design of microfluidic system for combinatorial electrochemical synthesis of conductive polymers. The device is composed of a gradient generator and a parallel electrochemical synthesis reactor. Two different species A and B were injected into the system from the top. Reprinted with permission from Xiang and La Van39 (copyright 2006 The Institute of Electrical and Electronics Engineers, Inc.)...

Schematic of the integrated microfluidic device, which consists of eight uniform structure units, and each unit is connected by a common reservoir in the center of device, (b) Magnified section of the singie structure unit containing an upstream concentration gradient generator (CGG) and downstream paraiiei ceii cuiture chambers, (c) Representative composite images from muitiparametric...

Knudsen pump The thermal gradients in microfluidic devices are used to pump fluid in a certain direction. A gas at low pressures is transferred from a cold chamber to a hot one due to the thermal gradients which generates slip velocity in the flow opposite to the direction of the tangential heat flux (Gad-el-Hakk, 1999). Knudsen pumps are useful at especially high Knudsen numbers deflned in the sidebar. 

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