Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The effect of {11}^B substitution on the superconductivity in MgCNi3   The crystal structure of boron doped superconducting
MgC_{1-x}{11}^B_{x}Ni_{3}, studied by powder neutron diffraction, is reported.
The solubility limit of boron is determined to be approximately x=0.16. The
unit cell expands from a = 3.81089(2) to 3.81966(2) Angstroms as x increases
from x=0 to x=0.155. Boron ({11}^B) doping decreases Tc with increasing x: from
7.09K (x=0) to 6.44K (x=0.155).

35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas