Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Empirical Formulae of Electrical and Thermal Conductivities of Elemental
  Metals at Room Temperature Ranges   We propose empirical formulae of the electrical conductivity sigma and
thermal conductivity for elemental metals such as Na, Cu or Fe at room
temperature ranges. Assuming the relaxation time is given by the Planck
constant divided by pai and further divided by the thermal energy kT for all
metals, we propose that sigma is given by the Drude form with the number
density of atoms instead of the electron number density, and further divided by
a single free integer parameter G. If we adopt that G is the sum of outer
electron numbers in electron configuration such as G=1 for Cu(4s^{1}),G=1+2=3
for In(5s^{2}4p^{1}) and G=5 for Nb(3d^{4}4s^{1}), the `absolute values' of
sigma and a similar one for the thermal conductivity agree with experiments
within ~20% for the majority of metals even including semimetals.

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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
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The categories of this paper are: solv-int
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The categories of this paper are: eess
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The categories of this paper are: atom-ph
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The categories of this paper are: physics
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
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The categories of this paper are: mtrl-th
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The categories of this paper are: econ
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The categories of this paper are: supr-con
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The categories of this paper are: adap-org
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-ph