Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Electroluminescence on-off ratio control of n-i-n GaAs/AlGaAs-based
  resonant tunneling structures
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn