Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Surface nanobubbles: Seeing is believing   The existence of surface nanobubbles has been previously suggested using
various experimental techniques, including attenuated total reflection
spectroscopy, quartz crystal microbalance, neutron reflectometry, and x-ray
reflectivity, but all of these techniques provide a sole number to quantify the
existence of gas over (usually) hundreds of square microns. Thus `nanobubbles'
are indistinguishable from a `uniform gassy layer' between surface and liquid.
Atomic force microscopy, on the other hand, does show the existence of surface
nanobubbles, but the highly intrusive nature of the technique means that a
uniform gassy layer could break down into nanobubbles \textit{due to} the
motion of the microscope's probe. Here we demonstrate \textit{optical}
visualisation of surface nanobubbles, thus validating their individual
existence non-intrusively.

34
The categories of this paper are: chem-ph
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org