Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the thermodynamic aspect of zinc oxide polymorphism. Calorimetric
  study of metastable rock salt ZnO   The enthalpies of dissolution of metastable rock salt and thermodynamically
stable wurtzite polymorphs of zinc oxide in aqueous H2SO4 have been measured in
direct calorimetric experiments at 303 K and 0.1 MPa and the obtained results
enabled determination of the standard enthalpy of the rock salt-to-wurtzite
phase transition in ZnO, {\Delta}trH = -11.7+/-0.3 kJ/mol.

22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
29
The categories of this paper are: funct-an
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph