Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Diffusion controlled oriented growth of a nano porous material by the
  Kirkendall effect   Nanotubes and nanoporous materials are being made by solid state diffusion
utilizing the Kirkendall effect. Recently published manuscripts have shown that
the product phase grows with an oriented microstructure. Based on the
requirement of relative mobilities of the components to produce a good quality
nanoporous material, it is shown that the oriented microstructure will grow
invariably in most of the systems.

9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
6
The categories of this paper are: astro-ph
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph