Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Oscillations in Rapid Fracture   Experiments of pure tensile fracture in brittle gels reveal a new dynamic
oscillatory instability whose onset occurs at a critical velocity, Vc = 0.87
Cs, where Cs is the shear wave speed. Until Vc crack dynamics are well
described by linear elastic fracture mechanics (LEFM). These extreme speeds are
obtained by suppression of the micro-branching instability, which occurs when
sample thicknesses are made comparable to the minimum micro-branch width. The
wavelength of these sinusoidal oscillations is independent of the sample
dimensions, thereby suggesting that a new intrinsic scale exists that is
unrelated to LEFM.

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The categories of this paper are: mtrl-th
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The categories of this paper are: ao-sci
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The categories of this paper are: nlin
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The categories of this paper are: cmp-lg
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The categories of this paper are: physics
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The categories of this paper are: hep-ph
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The categories of this paper are: supr-con
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The categories of this paper are: patt-sol
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The categories of this paper are: nucl-ex
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The categories of this paper are: solv-int
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The categories of this paper are: atom-ph
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The categories of this paper are: funct-an
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The categories of this paper are: alg-geom
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The categories of this paper are: econ
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The categories of this paper are: dg-ga
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The categories of this paper are: quant-ph