Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Zinc Sulphide Overlayer Two-Dimensional Photonic Crystal for Enhanced
  Extraction of Light from a Micro Cavity Light-Emitting Diode
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ