Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observation of a Transition from BCS to HTSC-like Superconductivity in
  Ba_{1-x}K_xBiO_3 Single Crystals   A study of temperature dependences of the upper critical field B_{c2}(T) and
surface impedance Z(T)=R(T)+iX(T) in Ba_{1-x}K_xBiO_3 single crystals that have
transition temperatures in the range 6 < T_c < 32 K (roughly 0.6>x>0.4) reveals
a transition from BCS to unusual type of superconductivity. B_{c2}(T) curves
corresponding to the crystals that have T_c>20 K have positive curvature (like
in some HTSC), and those of the crystals with T_c<15 K fall on the usual
Werthamer-Helfand-Hohenberg curve. R(T) and X(T) dependences of the crystals
with T_c~30 K and T_c~11 K are respectively linear (like in HTSC) and
exponential (BCS) in the temperature range T << T_c. The experimental results
are discussed in connection with the extended saddle point model by Abrikosov.

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The categories of this paper are: eess
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
37
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: econ
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: nlin
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The categories of this paper are: hep-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-alg