Laser-ultrasonic characterization of a zinc layer on a steel substrate using surface accoustic waves

Laser-ultrasonics and acoustic modeling were used to characterize the Lame coefficients (\u3bb, \u3bc) density (\u3c1) and thickness (h) of a zinc layer on a steel substrate. This characterization is based on fitting the measured velocity dispersion curve of surface acoustic waves (SAW) on a dispersion curve calculated using the conjugates gradients algorithm. The velocity dispersion curve of the Rayleigh wave was calculated in the frequency range of 1\u2013200 MHz and measurements were achieved from 5 to 50 MHz.Peer reviewed: YesNRC publication: Ye

Effect of chlorogenic acid on antioxidant activity of Flos Lonicerae extracts*

Flos Lonicerae is a medically useful traditional Chinese medicine herb. However, little is known about the antioxidant properties of Flos Lonicerae extracts. Here the antioxidant capacity of water, methanolic and ethanolic extracts prepared from Flos Lonicerae to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and reduce Fe3+ to Fe2+ is examined. Chlorogenic acid, a major component of Flos Lonicerae, is identified and further purified from 70% ethanolic extract with high performance liquid chromatography (HPLC) and its antioxidant capacity is characterized. The total phenolic compounds and chlorogenic acid contents in Flos Lonicerae are determined. The present results demonstrate that the Flos Lonicerae extracts exhibit antioxidant activity and chlorogenic acid is a major contributor to this activity