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81.
In droplet-based ("digital") microfluidics, liquid droplets in contact with dielectric surfaces are created, moved, merged and mixed by applying AC or DC potentials across electrodes patterned beneath the dielectric. We show for the first time that it is possible to manipulate droplets of organic solvents, ionic liquids, and aqueous surfactant solutions in air by these mechanisms using only modest voltages (<100 V) and frequencies (<10 kHz). The feasibility of moving any liquid can be predicted empirically from its frequency-dependent complex permittivity, epsilon*. The threshold for droplet actuation in air with our two-plate device configuration is /epsilon*/>8x10(-11). The mechanistic implications of these results are discussed, along with the greatly expanded range of applications for digital microfluidics that these results suggest are now feasible. 相似文献
82.
Anna Dall’Acqua Klaus Deckelnick Glen Wheeler 《Calculus of Variations and Partial Differential Equations》2013,48(3-4):293-313
In the class of surfaces with fixed boundary, critical points of the Willmore functional are naturally found to be those solutions of the Euler-Lagrange equation where the mean curvature on the boundary vanishes. We consider the case of symmetric surfaces of revolution in the setting where there are two families of stable solutions given by the catenoids. In this paper we demonstrate the existence of a third family of solutions which are unstable critical points of the Willmore functional, and which spatially lie between the upper and lower families of catenoids. Our method does not require any kind of smallness assumption, and allows us to derive some additional interesting qualitative properties of the solutions. 相似文献
83.
ABSTRACT. Let G be the group ?[t, t ?1] x ?. By studying the action of the braid group Bn on the set Gn , we obtain representations of Bn into a wreath product of the symmetric group and the general linear group over ?[t, t ?1]. This in particular recovers the Burau representation of the braid group. Furthermore, some quotients of the braid group are obtained by using the representations found. 相似文献
84.
85.
Kornauth Wilh Bersch A. Philips Christ. Kob und Co. Donner Louise H. Weller C. Schweitzer Ch. L. Penny Ed. van Melckebeke H. J. Wheeler B. Hartwell Knorr W. Büttner Barthé W. Jerwitz C. F. Parker Gust Christ Ferdinand Kryz J. Katz H. Göckel R. Jabota J. J. L. von Rijn F. Baum Joseph Nerking A. E. Taylor J. Gadamer C. Th. L. Hagemann und C. A. Neufeld 《Fresenius' Journal of Analytical Chemistry》1902,41(11):686-695
Ohne Zusammenfassung 相似文献
86.
Kornauth Wilh Bersch A. Philips Donner Dr. Louise H. Weller C. Schweitzer Ch. L. Penny Ed. van Melckebeke H. J. Wheeler B. Hartwell Knorr W. Büttner Barthé W. Jerwitz C. F. Parker Gust Christ Ferdinand Kryz J. Katz H. Göckel R. Jabota J. J. L. von Rijn F. Baum Joseph Nerking A. E. Taylor J. Gadamer C. Th. L. Hagemann C. A. Neufeld Christ. Kob und Co. 《Analytical and bioanalytical chemistry》1902,41(11):686-695
87.
88.
We solve a steady Darcy–Forchheimer flow in a bounded region by means of piecewise constant velocities and nonconforming piecewise
pressures. For the computation, we solve the nonlinearity by an alternating-directions algorithm and we decouple the computation
of the velocity from that of the pressure by a gradient algorithm. We prove a priori error estimates of the scheme and convergence
of the alternating-directions algorithm.
The first author was supported by the J. Tinsley Oden Faculty Fellowship, ICES, The University of Texas at Austin. 相似文献
89.
90.
Digital microfluidics for cell-based assays 总被引:1,自引:0,他引:1
We introduce a new method for implementing cell-based assays. The method is based on digital microfluidics (DMF) which is used to actuate nanolitre droplets of reagents and cells on a planar array of electrodes. We demonstrate that this method is advantageous for cell-based assays because of automated manipulation of multiple reagents in addition to reduced reagent use and analysis time. No adverse effects of actuation by DMF were observed in assays for cell viability, proliferation, and biochemistry. A cytotoxicity assay using Jurkat T-cells was performed using the new method, which had approximately 20 times higher sensitivity than a conventional well plate assay. These results suggest that DMF has great potential as a simple yet versatile analytical tool for implementing cell-based assays on the microscale. 相似文献