Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Intrinsic strength and failure behaviors of ultra-small single-walled
  carbon nanotubes   The intrinsic mechanical strength of single-walled carbon nanotubes (SWNTs)
within the diameter range of 0.3-0.8 nm has been studied based on ab initio
density functional theory calculations. In contrast to predicting "smaller is
stronger and more elastic" in nanomaterials, the strength of the SWNTs is
significantly reduced when decreasing the tube diameter. The results obtained
show that the Young`s modulus E significantly reduced in the ultra-small SWNTs
with the diameter less than 0.4 nm originates from their very large curvature
effect, while it is a constant of about 1.0 TPa, and independent of the
diameter and chiral index for the large tube. We find that the Poisson`s ratio,
ideal strength and ideal strain are dependent on the diameter and chiral index.
Furthermore, the relations between E and ideal strength indicate that
Griffith`s estimate of brittle fracture could break down in the smallest (2, 2)
nanotube, with the breaking strength of 15% of E. Our results provide important
insights into intrinsic mechanical behavior of ultra-small SWNTs under their
curvature effect.

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The categories of this paper are: atom-ph
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The categories of this paper are: eess
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The categories of this paper are: ao-sci
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The categories of this paper are: q-alg
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
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The categories of this paper are: nucl-th
3
The categories of this paper are: physics
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The categories of this paper are: nucl-ex
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The categories of this paper are: math-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: stat
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The categories of this paper are: supr-con
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The categories of this paper are: bayes-an
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The categories of this paper are: math
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The categories of this paper are: nlin