Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Wave focusing using symmetry matching in axisymmetric acoustic gradient
  index lenses   The symmetry matching between the source and the lens results of fundamental
interest for lensing applications. In this work we have modeled an axisymmetric
gradient index (GRIN) lens made of rigid toroidal scatterers embedded in air
considering this symmetry matching with radially symmetric sources. The sound
amplification obtained in the focal spot of the reported lens (8.24 dB
experimentally) shows the efficiency of the axisymmetric lenses with respect to
the previous Cartesian acoustic GRIN lenses. The axisymmetric design opens new
possibilities in lensing applications in different branches of science and
technology.

31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
5
The categories of this paper are: gr-qc
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th