Home About us Contact
|
Home About us Contact | ||
|
|
||
Optical Emission Spectroscopy (optical + emission_spectroscopy)
Selected AbstractsTailoring surface properties of cellulose acetate membranes by low-pressure plasma processingJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Chun Huang Abstract The aim of this study was to tailor the surface properties of cellulose acetate membranes using low-pressure plasma processing. Argon (Ar) plasma and Difluoromethane (CH2F2) plasma were used to control the surface wettabilities of cellulose acetate membranes. Optical emission spectroscopy was used to examine the various chemical species of low-pressure plasma processing. In this investigation, the plasma-treated surfaces were analyzed by X-ray photoelectron spectroscopy, while changes in morphology and surface roughness were determined with confocal laser scanning microscopy. Ar plasma activation resulted in hydrophilic surface. CH2F2 plasma deposited hydrophobic layer onto the cellulose acetate membrane because of strong fluorination of the top layer. The results reveal low-pressure plasma processing is an effective method to control the surface properties of cellulose acetate membranes. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Correlation of Optical Emission and Ion Flux with GaN Etch Rate in Inductively Coupled Ar/Cl2 Plasma EtchingPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2003S.A. Rizvi Abstract The etching of GaN was investigated in an Ar/Cl2 inductively coupled plasma. Optical emission spectroscopy and an ion flux probe were used to obtain insight into the etch mechanisms during processing. Langmuir probe measurements were also used to determine the basic Ar/Cl2 plasma characteristics. Etch rates of ,500 nm/min were obtained at relatively low Cl2 fractions of ,50%. The dominant emission species observed were Ga (at 294 nm) and up to six GaCl peaks between 320 and 345 nm. Plasma characterisation and ion flux indicate etch mechanisms that depend strongly on atomic chlorine but with increasing power and at low Cl2, the significance of ion-based processes cannot be ruled out. [source] Plasma-Induced Direct-Grafting on Polytetrafluoroethylene Films by Quasi-Glow Discharge at Atmospheric PressurePLASMA PROCESSES AND POLYMERS, Issue 12 2009Jun Wan Abstract Structurally well-defined poly(acrylic acid)s have been direct-grafted on polytetrafluoroethylene (PTFE) films by a quasi-glow discharge (QGD) using argon and acrylic acid. X-ray photoelectron spectroscopy (XPS) and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy provided obvious evidence for a high retention of the carboxylic acid group on PTFE surface, up to 77.5% of all carboxylic acid functional group. Optical emission spectroscopy (OES) indicated that polymerization proceeds predominantly via an opening of the CC bonds. The modified PTFE films were found to exhibit low water contact angle values and good ageing behavior. The mechanisms of plasma-induced direct-graft polymerization of acrylic acid on PTFE films were discussed combining with the real-time electrical and optical diagnostics of the QGD plasma. [source] Emission Intensity Enhancement of DC Arc Plasma Induced by External Oscillating Magnetic FieldCONTRIBUTIONS TO PLASMA PHYSICS, Issue 10 2007M. M. Stoiljkovi Abstract Direct current (dc) arc plasma with continuous aerosol supply was coupled with an external oscillatingmagnetic field of a few tens of mT and a frequency of up to 1 kHz. Such configuration was used to alter the plasma-related radiative properties. The magnetic field was oriented perpendicularly to the electric field in the plasma and forced the arc column to oscillate as a whole with respect to the surrounding atmosphere. The magnitude of the appliedmagnetic.eld controls the amplitude of the oscillatory motion. Several parameters that can contribute to the radiative properties of the plasma were investigated (arc current, composition of aerosol introduced into the plasma, amplitude and frequency of the magnetic field applied). Spectral emission from different zones of the plasma column was measured by optical emission spectroscopy (OES). In comparison to steady-state plasma, the applied magnetic field induces an intensity enhancement of emission of the most analytes considered. The intensity enhancement is strongly affected by the amplitude and frequency of plasma column oscillations, i.e. by plasma column velocity. Also, intensity enhancement depends on the plasma zone observed. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Experimental Study and Modelling of Formation and Decay of Active Species in an Oxygen DischargeCONTRIBUTIONS TO PLASMA PHYSICS, Issue 1 2005A.-M. Diamy Abstract A microwave (2.45 GHz) oxygen discharge (3 hPa, 150 W, 50 mL.min,1) is studied by optical emission spectroscopy of O(5P) (line 777.4 nm) and of the atmospheric system of O2(head-line 759.4 nm). Calibration of the spectral response of the optical setup is used to determine the concentrations of O(5P) and O2(b). The concentration of the O(5P) atoms is in the range 108,109 cm,3 and the concentration of the O2(b) molecules is in the range 1014 , 2 × 1014 cm,3 along the discharge tube. An attempt is made to simulate the experimental results by using coupling the Boltzmann equation, homogeneous energy transfer V-V and V-T, heterogeneous reactions on the walls (energy transfer and recombination of atoms) and a kinetic scheme (electronic transfer and chemical reactions). The Boltzmann equation includes momentum transfer, inelastic and superelastic processes and e-e collisions. V-V and V-T transfer equations are obtained from the SSH theory and the kinetic scheme includes 65 reactions with 17 species [electrons e, ions O, and O2,, fundamental electronic neutral species O(3P), O2, O2(X,v), O3 and excited neutral species O2(a), O2(b), O2(A), O(1D), O(1S), O(5P), O(4d 5Do), O(5s 5So), O(3d 5Do) and O(4s 5So)]. A fair agreement between experimental results and modelling is obtained with the following set of fitting values: , heterogeneous deactivation coefficient for O2(b) , = 2.6 × 10,2; , rate constant of reaction [O(1D) + O(3P) , 2 O(3P)] k34 = 1.4 × 10,11 cm3.s,1; , electron concentration in the range 1010 , 1011 cm,3. Modelling shows that the recombination coefficient for oxygen atoms on the silica wall (range 1.4 × 10,3 , 0.2 × 10,3) is of the same order as the values obtained in a previous paper and that the ratio ([O] / 2 [O2]initial) is about 33,50%. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Void formation in the Cu layer during thermal treatment of SiNx/Cu/Ta73Si27/SiO2/Si systemsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 1-2 2005R. Hübner Abstract The thermal stability of a SiNx passivation layer and its influence on the annealing behavior of an amorphous Ta73Si27 diffusion barrier deposited between copper and SiO2 were analyzed by X-ray diffraction, glow discharge optical emission spectroscopy, Auger electron spectroscopy, scanning electron microscopy, and transmission electron microscopy. During heat treatment at a temperature Tan = 500 °C, diffusion of Cu atoms out of the Cu metallization into the SiNx passivation occurs. The Cu diffusion intensifies with increasing annealing temperature and annealing time and seems to be a necessary precondition for a defect formation process observed within the Cu metallization. Depending on the chemical composition of the SiNx/Cu interface, voids in the ,m-range can be formed within the Cu film. Compared to an unpassivated sample, heat treatment leads to a reduced diffusion of Ta atoms from the barrier through the copper into the SiNx/Cu interface. The barrier crystallization process into Ta5Si3 occurring during annealing at Tan = 600 °C is principally not affected by the presence of a SiNx passivation. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Bauxite manufacturing residues from Gardanne (France) and Portovesme (Italy) exert different patterns of pollution and toxicity to sea urchin embryosENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2002Giovanni Pagano Abstract This study was designed to investigate the composition and toxicity of solid residues from bauxite manufacturing plants. Soil and dust samples were collected in the proximity of two bauxite plants (Gardanne, France, and Portovesme, Italy). Samples were analyzed for their content of some selected inorganic contaminants by means of inductively coupled plasma optical emission spectroscopy (ICP-OES) either following acid digestion procedures or by seawater release of soluble components. Toxicity was tested by sea urchin bioassays to evaluate a set of toxicity endpoints including acute embryotoxicity, developmental defects, changes in sperm fertilization success, transmissible damage from sperm to the offspring, and cytogenetic abnormalities. Inorganic analysis showed two distinct sets of inorganic contaminants in Gardanne versus Portovesme, including Al, Cr, Cu, Fe, Mn, Pb, Ti, and Zn; sample composition (seawater-soluble cotaminants) and toxicity showed a noteworthy association. The most severe toxicity to embryogenesis and to sperm fertilization success was exerted by some Portovesme samples (0.03,0.5% w/v), with a significant association between toxicity and dose-related seawater release of Zn, Pb, and Mn. Seawater extraction of a toxic dust sample (G20) from the Gardanne factory showed increasing seawater release of Al, Fe, and Mn; the G20 sample, at the level of 0.5%, affected both developing sea urchin embryos and sperm (offspring quality). Soil samples around the Gardanne factory showed the highest frequency of toxic soil sites eastward from the factory. The present data point to solid deposition from bauxite plants as a potential subject of environmental health concern. The results suggest that extraction methods for evaluating the toxicity of complex mixtures should be based on the environmental availability of mixture components. The differences in sample toxicity among the tested sites, however, suggest possible site-to-site variability in geochemical and/or technological parameters. [source] Bronze Age painted plaster in Mycenaean Greece: a pilot study on the testing and application of micro-Raman spectroscopyJOURNAL OF RAMAN SPECTROSCOPY, Issue 8-9 2004Ann Brysbaert Abstract Since the first discoveries of Minoan and Mycenaean painted plaster around the end of the 19th and early 20th centuries, iconographic and, to a lesser extent, technological studies have gone hand in hand in order to understand how these prehistoric societies were able to produce some of the earliest and most significant works of art in Bronze Age Europe and the eastern Mediterranean. These paintings claim to be among the first to be executed in the buon fresco technique. Past technological studies employed wet chemical methods, x-ray diffraction (XRD), optical emission spectroscopy and a range of microscopic techniques based on cross-sections of samples in order to investigate these fragmentary paintings. Most of these methods required destructive sampling and this is now, rightly so, very much restricted. Consequently, other non-micro-destructive approaches are being tested at present. Micro-Raman spectroscopy (MRS) has proven more than once its potential for non-destructive analysis of works of art and in archaeology in the recent past. Its application to this early fragmentary material is presented here for the first time. Interesting results were the identification of both organic (indigo) and non-crystalline materials (limonite), which complements the knowledge obtained from traditionally used techniques. Although not without problems (high fluorescence prevented identification of Egyptian Blue), non-destructive MRS yielded results comparable to XRD and provided the first identification of indigo blue on this medium, and can hence be considered very useful in future sample-reducing strategies considering these scarce materials. Copyright © 2004 John Wiley & Sons, Ltd. [source] Optical Emission Spectroscopy Analysis of Ar/N2 Plasma in Reactive Magnetron SputteringPLASMA PROCESSES AND POLYMERS, Issue S1 2009Angélique Bousquet Abstract The ternary silicon carbide-nitride SiCxNy presents very promising properties: hardness, low chemical reactivity, and resistance to oxidation. This material can be deposited by various processes, but reactive magnetron sputtering is one of the most versatile. In this paper, we investigated by optical emission spectroscopy an argon-nitrogen plasma used with a silicon carbide target to deposit SiCxNy films. First, we observed the physical aspect of the discharge is modified not only with the injected atmosphere but also with target surface state, which highly influences the N2 dissociation rate. Then, we followed two species coming from target sputtering: CN and Si. This study confirms the target nitriding up to a certain N2 fraction. Finally, the OES information was related to the deposited film composition. [source] A STUDY OF GLASS TESSERAE FROM MOSAICS IN THE MONASTERIES OF DAPHNI AND HOSIOS LOUKAS (GREECE)ARCHAEOMETRY, Issue 5 2010R. ARLETTI In this work 51 glass mosaic tesserae from decorations of the two Greek monasteries of Daphni and Hosios Loukas were analysed by inductively coupled plasma optical emission spectroscopy, electron microprobe analysis and X-ray powder diffraction. On the basis of the chemical analyses, after discrimination between the tesserae of the original decorations and those from other periods, it was possible to outline the distinctive traits of Byzantine mosaic tesserae. In both the monasteries, the original mosaics were decorated with tesserae produced with plant ash based glass, either of the typical composition or a mixture with natron type glass. The samples from the Hosios Loukas decorations show a more homogeneous composition compared with those from Daphni. The major differences among the original samples are due to the presence of opacifiers and colourants. [source] A SCIENTIFIC INVESTIGATION ON THE PROVENANCE AND TECHNOLOGY OF A BLACK-FIGURE AMPHORA ATTRIBUTED TO THE PRIAM GROUP*ARCHAEOMETRY, Issue 1 2006P. MIRTI The restoration of a Greek black-figure amphora provided an opportunity to study the provenance and production technology of the vase. The composition of the ceramic body, determined by inductively coupled plasma optical emission spectroscopy (ICP,OES), matches that of Attic products. Investigation by X-ray diffraction and reflectance spectroscopy suggests a maximum firing temperature around 900°C and a body re-oxidation temperature around 800°C, respectively. The morphology and composition of black, red and dark red surface areas were studied by scanning electron microscopy and X-ray energy-dispersive analysis; the black areas show the features of a typical well-vitrified black gloss, while the red areas were most probably obtained by simple burnishing of the body; the dark red additions, on the other hand, are the likely result of a partial re-oxidation of a clay,ochre mixture. [source] Plasma Characterization of Oxygen-Tetramethylsilane Mixtures for the Plasma-Enhanced CVD of SiOxCyHz Thin Films,CHEMICAL VAPOR DEPOSITION, Issue 12 2006Á. Yanguas-Gil Abstract The plasma-enhanced (PE)CVD of SiOxCyHz thin films from O2/Ar/tetramethylsilane (TMS) mixtures, in a low-pressure microwave electron cyclotron resonant (ECR) plasma reactor, has been studied. The discharge has been analyzed by mass spectrometry (MS) and optical emission spectroscopy (OES) for varying amounts of oxygen in the gas mixture both in the presence and in the absence of argon. The films obtained have been characterized by Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). It is found that the electron impact of the TMS molecules and their dissociative ionization play an important role in the deposition process. Si(OH)x(CH3)3,x species, produced by reactions between the Si(CH3)4 molecule and Si(CH3)3+ ion fragments with O and O2, have been identified as important reaction intermediates. Such species form in different proportions depending on the O2/TMS ratio in the gas mixture. It is proposed that their incorporation onto the surface of the growing films accounts for the wide range of compositions achieved (ranging from SiO2 to almost Si:C:H) and the high concentration of Si-C bonds experimentally detected in the SiOxCyHz thin films. [source] Characterization of Silver Trimethylacetate Complexes with Tertiary Phosphines as CVD Precursors of Thin Silver Films,CHEMICAL VAPOR DEPOSITION, Issue 1 2005P. Piszczek Abstract AgI complexes [Ag(O2CtBu)(PMe3)] (1) and [Ag(O2CtBu)(PEt3)] (2) were used as CVD precursors. Silver films between 30,nm and 100,nm were deposited from the above compounds using hot-wall and cold-wall CVD techniques on Si(111) and Si(100) substrates in the temperature range 180-220,°C, under the reactor pressure 1,3,mbar. Metallic films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), glow discharge optical emission spectroscopy (GDOES), scanning electron microscopy (SEM), and conductivity measurements. [source] | |||||||||||||