Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Carbon Nanotube Based Bearing for Rotational Motions   We report the fabrication of a nanoelectromechanical system consisting of a
plate rotating around a multiwalled nanotube bearing. The motion is possible
thanks to the low intershell friction. Indeed, the nanotube has been engineered
so that the sliding happens between different shells. The plate rotation is
activated electrostatically with stator electrodes. The static friction force
is estimated at $\approx 2\cdot10^{-15}$ N/\AA$^2$.

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The categories of this paper are: mtrl-th
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The categories of this paper are: astro-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: stat
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The categories of this paper are: adap-org
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The categories of this paper are: eess
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The categories of this paper are: hep-ex
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The categories of this paper are: supr-con
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The categories of this paper are: comp-gas
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The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int
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The categories of this paper are: patt-sol
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The categories of this paper are: bayes-an
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The categories of this paper are: dg-ga
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The categories of this paper are: q-bio