Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gravitational Annealing of Colloidal Crystals   A silica colloidal crystal obtained by centrifugation at 9 G for 2 days in
water was annealed by additional stronger centrifugation at 50 G for 5 days.
The number of the striations observed in the colloidal crystal under crossed
polarized light decreased at some parts in a growth container after additional
centrifugation, while the number alse increase at the other parts. The decrease
probably shows the shrinkage of the stacking disorders under high gravity,
while the increase probably shows the production of new stacking disorder.

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The categories of this paper are: gr-qc
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The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: supr-con
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The categories of this paper are: solv-int
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The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin