Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measuring thermal conductivity in extreme conditions: sub-Kelvin
  temperatures and high (27 T) magnetic fields   We present a one-heater-two-thermometer set-up for measuring thermal
conductivity and electric resistivity of a bulk sample at low temperatures down
to 0.1 K and in magnetic fields up to 27 Tesla. The design overcomes the
difficulties emerging in the context of large water-cooled resistive magnets.

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The categories of this paper are: astro-ph
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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: dg-ga
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The categories of this paper are: q-alg
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The categories of this paper are: hep-th
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-lat
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The categories of this paper are: math
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The categories of this paper are: atom-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: eess
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The categories of this paper are: gr-qc
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The categories of this paper are: q-fin
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The categories of this paper are: adap-org