Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Mass Density of Individual Cobalt Nanowires   The mass density of nanowires is determined using in-situ resonance frequency
experiments combined with quasi-static nanotensile tests. Our results reveal a
mass density of 7.36 g/cm3 on average which is below the theoretical density of
bulk cobalt. Also the density of electrodeposited cobalt nanowires is found to
decrease with the aspect ratio. The results are discussed in terms of the
measurement accuracy and the microstructure of the nanowires.

31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ