Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A molecular dynamics study on the equilibrium magnetization properties
  and structure of ferrofluids   We investigate in detail the initial susceptibility, magnetization curves,
and microstructure of ferrofluids in various concentration and particle dipole
moment ranges by means of molecular dynamics simulations. We use the Ewald
summation for the long-range dipolar interactions, take explicitly into account
the translational and rotational degrees of freedom, coupled to a Langevin
thermostat. When the dipolar interaction energy is comparable with the thermal
energy, the simulation results on the magnetization properties agree with the
theoretical predictions very well. For stronger dipolar couplings, however, we
find systematic deviations from the theoretical curves. We analyze in detail
the observed microstructure of the fluids under different conditions. The
formation of clusters is found to enhance the magnetization at weak fields and
thus leads to a larger initial susceptibility. The influence of the particle
aggregation is isolated by studying ferro-solids, which consist of magnetic
dipoles frozen in at random locations but which are free to rotate. Due to the
artificial suppression of clusters in ferro-solids the observed susceptibility
is considerably lowered when compared to ferrofluids.

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The categories of this paper are: q-bio
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The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
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The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
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The categories of this paper are: hep-ph
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The categories of this paper are: cs
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int
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The categories of this paper are: funct-an