Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Sonochemical Modification of the Superconducting Properties of MgB2   Ultrasonic irradiation of magnesium diboride slurries in decalin produces
material with significant inter-grain fusion. Sonication in the presence of
Fe(CO)5 produces magnetic Fe2O3 nanoparticles embedded in the MgB2 bulk. The
resulting superconductor-ferromagnet composite exhibits considerable
enhancement of the magnetic hysteresis, which implies an increase of vortex
pinning strength due to embedded magnetic nanoparticles.

9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn