Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Lateral Separation of Macromolecules and Polyelectrolytes in
  Microlithographic Arrays   A new approach to separation of a variety of microscopic and mesoscopic
objects in dilute solution is presented. The approach takes advantage of unique
properties of a specially designed separation device (sieve), which can be
readily built using already developed microlithographic techniques. Due to the
broken reflection symmetry in its design, the direction of motion of an object
in the sieve varies as a function of its self-diffusion constant, causing
separation transverse to its direction of motion. This gives the device some
significant and unique advantages over existing fractionation methods based on
centrifugation and electrophoresis.

30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex