This work studied the effect of additions of carbon dioxide to argon shielding gas on the weld shape and microstructure of ST14 steel in pulsed Nd: YAG laser welding. By additions of carbon dioxide up to 15%,the weld area and depth/width ratio decreases while rising of carbon dioxide up to 25% causes increasing of weld area and depth/width ratio. It is observed that the weld metal microstructur...

background and aims: although dental caries is a preventable disease, it is still common and remains a public health problem. one of the potentially effective preventive measures is laser irradiation. raman spectroscopy is a powerful technique for studying the microcrystalline structure of dental enamel. the study assessed the chemical alterations occurring in enamel irradiated with er:yag or n...

Single-crystal (SC) fibers have the potential of delivering extremely high laser energies. Sapphire fibers have been the most commonly studied SC fiber and the losses for sapphire fibers have been as low as 0.4 dB/m for a 300micron core-only fiber at 3 microns. In this study we report on the growth of SC yttrium aluminum garnet, Y3Al5O12 (YAG) fibers from undoped SC source rods using the Laser ...

introduction: the purpose of the present study was to determine the effect of 17% ethylene,di-amine, tetra-acetic acid (edta), 6% phosphoric acid and erbium: yttrium, aluminum, garnet (er:yag) laser in removing the smear layer by scanning electron microscopy. methods: in this study, 80 single-rooted human teeth were selected. instrumentation was done by use of hand files and step-back technique...

FTR-Raman Spectra of human dental enamel, both laser-irradiated and untreated, are reported. Spectra are compared with hydroxyapatite. It is evident that unlike the CO2 laser, the Nd/YAG laser does not induce any chemical change in dental enamel.