Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Influence of Defects on Photoconductivity and Photocatalytic Activity of
  Nitrogen-Doped Titania
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph