Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Reversed flow at low frequencies in a microfabricated AC electrokinetic
  pump   Microfluidic chips have been fabricated to study electrokinetic pumping
generated by a low voltage AC signal applied to an asymmetric electrode array.
A measurement procedure has been established and followed carefully resulting
in a high degree of reproducibility of the measurements. Depending on the ionic
concentration as well as the amplitude of the applied voltage, the observed
direction of the DC flow component is either forward or reverse. The impedance
spectrum has been thoroughly measured and analyzed in terms of an equivalent
circuit diagram. Our observations agree qualitatively, but not quantitatively,
with theoretical models published in the literature.

19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci