1,721,064 research outputs found
Distribution constant and thermodynamic properties of transfer of 1-Pentanol from acqueous to micellar phase (?G°T, ?V°T, ?H°T, ?S°T) from 25°C to 130°C at 2 and 19 Mpa
No full textExperimental characterization of metallic titanium-laser induced plasma by time and space resolved optical emission spectroscopy
No full textTime and space resolved optical emission spectroscopy has been successfully employed to investigate the evolution of the plasma produced by the interaction of UV laser beam with a metallic target of titanium at two different pressures (10-5 and 3.4 × 10-2 torr) and at distances up to 3 mm from the target. By time of flight measurements and Boltzmann plots both the dynamic and the kinetic aspects have been discussed. The quasi-equilibrium state of the laser-induced plasma has been established on the basis of the failure of Saha balance equation. The effect of three-body recombination on atomic titanium temporal distribution has been explained. Temporal evolution of electron number density, as determined by Stark effect, has been used for the estimation of the three-body recombination rate constant. © 2002 Elsevier Science B.V. All rights reserved
Preface to "A Selection of Papers Presented at the 5th Euro-Mediterranean Symposium on Laser Induced Breakdown Spectroscopy (EMSLIBS 2009)"
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A novel approach to elemental analysis by Laser Induced Breakdown Spectroscopy based on direct correlation between the electron impact excitation cross section and the optical emission intensity
No full textIn Laser Induced Plasma Spectroscopy (LIPS) or Laser Induced Breakdown Spectroscopy (LIBS) the relation between recombining electrons and optical emission intensity has been studied in hydrogen and different metals targets. The role played by the electron impact excitation cross section on the temporal trend of emission lines has addressed and a methodology for the evaluation of the excitation cross sections by optical emission spectroscopy has been tested on several species including H I, Fe I, Ni I, Co I and Ti II. In connection with the theory drawn in this paper, the results show a good agreement with respect to theoretical ones. These results allow the direct linking of the emission intensity to the electronic excitation binary collision. The latter does not depend on experimental conditions and can be applied for elemental analysis. The use of estimated cross sections forms the basis for a different calibration free approach. LIBS elemental analysis on iron meteorites (to be considered as ternary alloys) and on a set of copper based alloys demonstrates the promising use of this analytical approach
Laser Induced Plasma Spectroscopy by Air Spark Ablation
No full textIn this work, a diagnostic method for solid layer analysis based on LIBS (laser induced breakdown spectroscopy) has been proposed for minimizing the damage on the sample surface. In this method the focus of laser is placed some millimetres distance from the target surface so that an air spark is generated close to the target surface. The particles are removed from the target mainly by air plasma etching instead of direct laser-solid interaction. In this way, it is not necessary to expose the target surface to high laser energy so that the damage on the sample is really superficial. Here preliminary results on a hard alloy as 25CrMo4 and on a sintered TiO tablet are shown
A Bronze Age Pre-Historic DOLMEN: Laser Cleaning Techniques of Paintings and Graffiti (The BISCEGLIE DOLMEN case of study)
No full textThe effect of Oxygen Discharge on Pulsed Laser Deposition of Metallic Oxides
No full textIn this work final results on TiO2 film deposition by Plasma Assisted Pulsed Laser Deposition (PAPLD) with an rf biased substrate are presented. In previous work it has been shown that PAPLD is an improvement over conventional PLD for the elimination of particulates in high refractive index thin film deposition. This paper will give a comparison between conventional PLD and PAPLD on the stoichiometry, morphology, and optical properties of deposited TiO2 films. It will be demonstrated that oxygen rf discharge during the PLD process makes incorporation of oxygen into the depositing films extremely effective. This effect of the rf discharge allows operation of the PLD process at a lower oxygen background pressure while enhancing the deposition rate. Also, the production of a good quality TiO2 film by PAPLD using a pure metal titanium target will be shown
Thermodynamic Properties of Sodium n-Perfluoroalkanoates in Water and in Water+Cyclodestrins Mixtures
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