Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Elastic constants of borocarbides. New approach to acoustic Measurement
  technique   A new version of the phase method of determining the sound velocity is
proposed and implemented. It utilizes the ``Nonius'' measurement technique and
can give acceptable accuracy (~1%) in samples of submillimeter size.
Measurements of the sound velocity are made in single-crystal samples of the
borocarbides RNi2B2C (R = Y,Lu,Ho). The elastic constants and the Debye
temperature are calculated.

33
The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph