Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A robust platform cooled by superconducting electronic refrigerators   A biased tunnel junction between a superconductor and a normal metal can cool
the latter electrode. Based on a recently developed cooler with high power and
superior performance, we have successfully integrated it with a dielectric
silicon nitride membrane, and cooled phonons from 305 mK down to 200 mK.
Without perforation and covered under a thin alumina layer, the membrane is
rigorously transformed into a cooling platform that is robust and versatile for
multiple practical purposes. We discuss our results and possibilities to
further improve the device.

6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
24
The categories of this paper are: dg-ga
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
23
The categories of this paper are: solv-int