DOI: 10.1016/j.sab.2017.09.014

Authors
Fan, Z. W. ; Li, X. ; Lian, F. Q. ; Lin, W. R. ; Liu, Y. ; Mo, Z. Q. ; Nie, S. Z. ; Wang, P. ; Xiao, H. ; Zhang, H. B. ; Zhong, Q. X.

Keywords

LIBS instrument design; Liquid steel analysis; On-line process monitoring; Vacuum alloys production; Laser-induced breakdownspectroscopy;LIBS; STEEL

Abstract

Laser-induced breakdown spectroscopy (LIBS) utilizing an echelle spectrograph-ICCD system is employed for online analysis of elements concentration in a vacuum induction melting workshop. Active temperature stabilization of echelle spectrometer is implemented specially for industrial environment applications. The measurement precision is further improved by monitoring laser parameters, such as pulse energy, spatial and temporal profiles, in real time, and post-selecting laser pulses with specific pulse energies. Experimental results show that major components of nickel-based alloys are stable, and can be well detected. By using internal standard method, calibration curves for chromium and aluminum are obtained for quantitative determination, with determination coefficient (relative standard deviation) to be 0.9559 (<22%) and 0.9723 (<2.8%), respectively. (C) 2017 Elsevier B.V. All rights reserved.

DOI: 10.1117/12.2245276

Authors
Fan, Z. W. ; Juhasz, T. ; Kurtz, R. ; Li, X.

Keywords

laser induced breakdown spectroscopy (LIBS); Acoustic Radiation Force Elasticity Microscope(ARFEM); ultrasonic transducer; Femtosecond laser; corneal elasticity;STRENGTH

Abstract

The nonhomogeneous structure of the cornea suggests a unique spatial distribution of corneal elasticity. Non-invasive measurement of this distribution is critical to understanding how biomechanics control corneal stability and refraction. Femtosecond laser pulses induced optical breakdown and produced cavitation in the anterior and posterior cornea. A confocal ultrasonic transducer applied 6.5 ms acoustic radiation force-chirp bursts to the bubble at 1.5 MHz while monitoring bubble position using pulse-echoes at 20 MHz. The laser induced breakdown spectroscopy (LIBS) were measured in the anterior and posterior cornea to see whether the laser induced plasmas signals will show relationship to Young's modulus.