[1] Yanbin Chen, Zhenglong Lei, Liqun Li et al.. Influence of shielding gas pressure on welding characteristics in CO2 laser-MIG hybrid welding process[J]. Chin. Opt. Lett., 2006, 4(1): 33～35

[2] K. Bockasten. Transformation of observed radiances into radial distribution of the emission plasma[J]. J. Opt. Soc. Am., 1961, 51(9): 943～947

[3] M. Kalal, K. A. Nugent. Abel inversion using fast Fourier transforms[J]. Appl. Opt., 1998, 27(10): 1956～1959

[4] L. M. Smith, D. R. Keefer, S. I. Sudharsanan. Abel inversion using transform techniques[J]. J. Quant. Spectrosc. Radiat. Transfer, 1998, 39(5): 367～373

[6] A. Savitzky, M. J. E. Golay. Smoothing and differentiation of data by simplified least squares procedures[J]. Anal. Chem., 1964, 36(8): 1627～1639

[7] J. I. Fernández Palop, J. Ballesteros, V. Colomer et al.. A new smoothing method for obtaining the electron energy distribution function in plasmas by the numerical differentiation of the Ⅰ-Ⅴ probe characteristic[J]. Rev. Sci. Instrum., 1995, 66(9): 4625～4636

[9] U. Engel, C. Prokisch, E. Voges et al.. Spatially resolved measurements and plasma tomography with respect to the rotational temperatures for a microwave plasma torch[J]. J. Anal. At. Spectrom., 1998, 13: 955～961

[10] F. Knemann, G. Kühn, J. Reiche et al.. Near-cathode region of a free-burning arc: a spectroscopic investigation[J]. J. Phys. D: Appl. Phys., 2004, 37(2): 171～179