Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Drift effects and the average features of cosmic ray density gradient in
  CIRs during successive two solar minimum periods
28
The categories of this paper are: alg-geom
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
4
The categories of this paper are: cond-mat
30
The categories of this paper are: q-alg