Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Calibration-free wavelength modulation spectroscopy based on even-order
  harmonics   This paper proposes a novel and rapid calibration-free wavelength modulation
spectroscopy algorithm based on even-order harmonics. The proposed algorithm,
analytically deduced from Voigt line-shape function, only involves simple
algebraic operations to describe the actual gas absorption spectra, thus
eliminating the time-consuming simulations and line-shape fitting procedures
adopted in traditional algorithms. Instead of acquiring the entirely scanned
absorption line-shape, the proposed technique only requires extraction of the
peak values of the harmonics. This characteristic significantly benefits gas
diagnosis at elevated pressure and/or temperature, in which the entirely
scanned absorption is very difficult to be obtained due to the broadened
line-shapes. The proposed algorithm is validated by both numerical simulation
and condition-controlled experiment, indicating millisecond-level calculation
of gas parameters with the relative error less than 4% in the experiments.

29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
2
The categories of this paper are: math
34
The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol