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1
Feltham, David John. "Trace element studies by proton microprobe analysis." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.258766.
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Harris, A. W. "Laser microprobe mass spectrometry - quantitative inorganic analysis." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233975.
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This thesis is concerned with the application of Laser Microprobe Mass Spectrometry (LAMMS) to the microanalysis of inorganic materials and in particular to the quantification of such analyses. The investigation consists both of an assessment of the capabilities of a LAMMS instrument, the Cambridge Mass Spectrometry LIMA 2A, and an attempt to correlate experimental results with theoretical predictions. The principles of the operation of a LAMMS instrument are discussed and a description of the LIMA 2A instrument is presented. A survey of the literature concerned with the interaction of a high-powered laser with a solid specimen to produce a plasma, the basis of the LAMMS technique, is included. Particular emphasis is given to the description of this interaction in terms of a model based on a local thermodynamic equilibrium (LTE) in the plasma. This model is applied to the conditions estimated to be produced in the LIMA instrument to make simple predictions of expected results. A discussion of the possible methods for converting LAMMS data into a quantitative analysis is given, along with a brief description of the statistical techniques used for data handling. Several model materials, principally chosen for their well-defined composition and known lateral homogeneity, are used in this work. These are single-crystal silicon, a binary copper-nickel alloy and three III-V semiconductors drawn from the Ga-In-As system. The effect of the instrument itself is investigated, with a view to establishing its contribution to the errors observed in the data. This is followed by an investigation of the variation of both the absolute and relative ion signals produced. The variations in the relative ion signals are then compared with the predictions of the LTE model in an attempt to establish its validity. This comparison is also used to estimate the conditions produced in the laser-induced plasma and their variation with specimen chemistry and laser power density. The general conclusions of the investigation are drawn together in a discussion of the preferred methods for the quantification of LAMMS data and the expected error in the resulting analysis. It is shown that, provided appropriate methods are used, the LAMMS technique can provide quantitative analyses with precisions of about 5-20%.
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Mulware, Stephen Juma. "Analysis of Biological Materials Using a Nuclear Microprobe." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc700099/.
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The use of nuclear microprobe techniques including: Particle induced x-ray emission (PIXE) and Rutherford backscattering spectrometry (RBS) for elemental analysis and quantitative elemental imaging of biological samples is especially useful in biological and biomedical research because of its high sensitivity for physiologically important trace elements or toxic heavy metals. The nuclear microprobe of the Ion Beam Modification and Analysis Laboratory (IBMAL) has been used to study the enhancement in metal uptake of two different plants. The roots of corn (Zea mays) have been analyzed to study the enhancement of iron uptake by adding Fe (II) or Fe (III) of different concentrations to the germinating medium of the seeds. The Fe uptake enhancement effect produced by lacing the germinating medium with carbon nanotubes has also been investigated. The aim of this investigation is to ensure not only high crop yield but also Fe-rich food products especially from calcareous soil which covers 30% of world’s agricultural land. The result will help reduce iron deficiency anemia, which has been identified as the leading nutritional disorder especially in developing countries by the World Health Organization. For the second plant, Mexican marigold (Tagetes erecta), the effect of an arbuscular mycorrhizal fungi (Glomus intraradices) for the improvement of lead-phytoremediation of lead contaminated soil has been investigated. Phytoremediation provides an environmentally safe technique of removing toxic heavy metals (like lead), which can find their way into human food, from lands contaminated by human activities like mining or by natural disasters like earthquakes. The roots of Mexican marigold have been analyzed to study the role of arbuscular mycorrhizal fungi in enhancement of lead uptake from the contaminated rhizosphere.
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Mars, Johan Andre. "The application of nuclear microprobe analysis in materials science." Thesis, Peninsula Technikon, 2003. http://hdl.handle.net/20.500.11838/1513.
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Thesis (DTech (Science))--Peninsula Technikon, Cape Town, 2003.The impetus for the refinement and renewal of daily-used products has spurred international interest in investigating the small in homogeneities that might exist in these products. This interest has become an important part in the design philosophy, which is based on structural information gained by the analysis of these products. It is this drive that initiated the study to investigate the simultaneous use of novel nuclear analytical techniques such as micro proton induced X-ray emission( u-PlXE), micro proton induced gamma-ray emission (u-PlGE) and micro proton backscattering (u-RBS) to achieved a broader and yet deeper insight into the fine structure of products. The fundamental underlying physical principles of these techniques are discussed to gain in-depth knowledge on how to them to obtain the desired information. Also determined was the degree of accuracy that could be attained in the application of this knowledge. These principles were evaluated in conjunction with the instrumentation with which the applicability of these techniques could then be further extended. More so is the use of sophisticated software that facilitated the use of both physical and instrumental parameters. After describing the necessary implements to achieve this further know-how, products of industrial origin were investigated to determine in homogeneities that existed in those products and compared those theoretical values. The first application was made to ceramic-based sorption electrodes to be used in the purification of wastewater.
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Mutchler, Scott R. "Oxygen stable isotopic analysis of calcite by Raman microprobe spectrometry." Thesis, This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-05092009-040655/.
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Li, Jia Zheng. "A comparison of the performance of a low voltage microprobe for two thermal field emitters." Full text open access at:, 1986. http://content.ohsu.edu/u?/etd,98.
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Summerour, Jamie Maddox. "Tritium doped polyaniline as a β-irradiation source". Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/26962.
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Manuel, Jack Elliot. "Design, Construction, and Application of an Electrostatic Quadrupole Doublet for Heavy Ion Nuclear Microprobe Research." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1062819/.
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A nuclear microprobe, typically consisting of 2 - 4 quadrupole magnetic lenses and apertures serving as objective and a collimating divergence slits, focuses MeV ions to approximately 1 x 1 μm for modification and analysis of materials. Although far less utilized, electrostatic quadrupole fields similarly afford strong focusing of ions and have the added benefit of doing so independent of ion mass. Instead, electrostatic quadrupole focusing exhibits energy dependence on focusing ions. A heavy ion microprobe could extend the spatial resolution of conventional microprobe techniques to masses untenable by quadrupole magnetic fields. An electrostatic quadrupole doublet focusing system has been designed and constructed using several non-conventional methods and materials for a wide range of microprobe applications. The system was modeled using the software package "Propagate Rays and Aberrations by Matrices" which quantifies system specific parameters such as demagnification and intrinsic aberrations. Direct experimental verification was obtained for several of the parameters associated with the system. Details of the project and with specific applications of the system are presented.
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Verhoef, Bastiaan Abram Willem. "Elemental analysis of ischemic and reperfused rat heart tissue using the proton microprobe." Maastricht : Maastricht : Universiteit Maastricht ; University Library, Maastricht University [Host], 1997. http://arno.unimaas.nl/show.cgi?fid=5932.
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Enami, Masaki, Takenori Kato, 正樹 榎並 та 丈典 加藤. "CHIMEの現状と利用(2012年度)". 名古屋大学年代測定資料研究センター, 2013. http://hdl.handle.net/2237/20114.
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Freebody, Nicola. "The use of Raman microprobe spectroscopy in the analysis of electrically aged polymeric insulators." Thesis, University of Southampton, 2012. https://eprints.soton.ac.uk/346963/.
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Due to its applications in high voltage insulation, a thorough understanding of the chemical reactions that occur during electrical ageing in polymers is needed. A confocal Raman microscope has a potential lateral resolution of ~1μm along both the lateral and optic axes and is able to characterise the localised chemical composition of a material; for this reason, it has been applied in the study of electrical ageing in solid dielectrics. Due to inaccurate assumptions about the optical processes involved in confocal Raman microprobe spectroscopy (CRMS), however, the exact characterisation of the processes and chemicals involved has previously proven to be difficult. The objective of this study is to apply the technique of Raman microprobe spectroscopy in the analysis of the chemical structures of electrically aged polymers. It was found that, with the application of immersion oil and by using a refined version of a model of CRMS which is based on a photon scattering approach; CRMS is a valuable tool in the study of polymers. More accurate results can be obtained, however, by revealing the feature in question to the surface and applying non confocal Raman microprobe spectroscopy (RMS). CRMS was applied to a variety of polymeric samples containing electrically aged voids and electrical trees. Results showed that within the electrically aged voids, chemical signatures similar to those previously found in electrical trees in PE can be found. Finally, a variety of polymeric insulators was subjected to spark ageing and corona discharge. The by-products of these ageing mechanisms were then characterized using RMS in an attempt to reproduce in bulk the chemical compounds formed in electrical treeing. The resulting Raman spectra indicated that the same by-products as those formed in voids and trees are indeed formed. Where possible all results were compared to comparative data obtained using Fourier transform infra red (FTIR) spectroscopy and scanning electron microscopy (SEM) and discussed in relation to previously published work.
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Kerckhove, Diane G. de. "The design, implementation and applications of a beam rocking system for a nuclear microprobe." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326002.
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King, Jason Peters King. "An investigation of spin-valves and related films by TEM." Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301949.
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Reinert, Tilo. "Focussed MeV-Ion Micro- and Nano-Beams in the Life Sciences." Doctoral thesis, Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-197802.
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This work presents the development of a sub-micron nuclear microprobe for applications in the life sciences. It includes quantitative trace element analysis with sub-micron spatial resolution, 2D- and 3D-microscopy of density distributions and the targeted irradiation of living cells with counted single ions. The analytical methods base on particle induced X-ray emission spectrometry (PIXE), Rutherford backscattering spectrometry (RBS), scanning transmission ion microscopy (STIM) and STIM-tomography. The specific development of the existing nuclear microprobe LIPSION led to an improved performance of the capabilities for trace element analysis. For sub-micron analysis the spatial resolution could be improved to 300 nm at a sensitivity of about 1 µg/g for metal ions in biological matrices; for a resolution of 1 µm the sensitivity was improved to 200 ng/g (3 µmol/l). This habilitation thesis comprises a short general introduction including the motivation to utilize focussed high energy ion beams, an overview on the applications and actual research fields. The introduction is followed by the basic principles of the equipments and analytical methods. An estimation of the limits of resolution for element analytical and single ion techniques is given for the Leipzig system. Thereafter, selected studies from different research areas are presented. The first presented application is a study from environmental air pollution research. It is demonstrated that the microscopic elemental analysis of single aerosol particles can be used to assess the contributions from different sources. A further example is the analysis of the distribution of nanoparticles in skin cross-sections for a risk assessment of the applications of nanosized physical UV-filters in cosmetic products. The risk assessment is followed by the micro-analysis of trace elements, especially of bound metal ions, in brain sections on the cellular and sub-cellular level. After this the application of focussed MeV ion beams in low dose radiobiological research is presented. Finally, the analysis of 3D-density distributions by proton micro-tomography is demonstrated. A summary concludes on the applications and gives an outlook to further applications and methodological developments. The appendix comprises the relevant publications of the authorDie vorliegende Arbeit etabliert für Anwendungen in den Lebenswissenschaften den Einsatz hochfokussierter MeV-Ionenstrahlen für nuklear-mikroskopische Methoden der quantitativen Spurenelementanalyse, der 2D- und 3D-Dichtemikroskopie sowie für die gezielte Bestrahlung einzelner lebender Zellen für radiobiologische Experimente. Zur Anwendung kamen die Methoden ortsaufgelöste Protonen induzierte Röntgenfluoreszenzanalyse (particle induced X-ray emission - PIXE), Spektrometrie rückgestreuter Ionen (Rutherford backscattering spectrometry - RBS) und Rastertransmissionsionenmikroskopie (scanning transmission ion microscopy - STIM). Durch eine gezielte Weiterentwicklung des bestehenden Ionenstrahlmikroskops, der Hochenergie Ionennanosonde LIPSION, konnte die Ortsauflösung für Spurenelementanalyse auf unter 300 nm verbessert werden, beziehungsweise die Sensitivität für Metallionen in biologischen Proben auf unter 200 ng/g (3 µmol/l) bei einer Ortsauflösung von 1 µm verbessert werden. Die Habilitationsschrift umfasst eine kurze allgemeine Einleitung einschließlich der Motivation für den Einsatz fokussierter MeV-Ionenstrahlen sowie einen Überblick über die Anwendungsgebiete und aktuellen Forschungsschwerpunkte. Danach werden kurz die Grundlagen der Technik und Methoden vorgestellt, gefolgt von einer Abschätzung der Auflösungsgrenzen für Elementanalysen und Einzelionentechniken. Danach werden ausgewählte Anwendungen aus verschiedenen Forschungsgebieten vorgestellt. Das erstes Beispiel ist aus der Umweltforschung. Es wird dargestellt, wie mittels ortsaufgelöster Elementspektroskopie eine Abschätzung der Feinstaubbelastung nach Beiträgen einzelner Verursacherquellen erfolgen kann. Dann folgt als Beispiel eine ortsaufgelöste Analyse der Verteilung von Nanopartikeln aus Sonnencremes in Hautquerschnitten zur Risikoabschätzung der Anwendungen von Nanotechnologie in kosmetischen Produkten. Desweiteren werden Studien der Spurenelementverteilung, speziell der von gebundenen Metallionen, in Hirnschnitten auf zellulärer und subzellulärer Ebene erläutert. Das anschließende Beispiel erläutert die Anwendung niedriger Energiedosen in der Radiobiologie anhand des Beschusses einzelner lebender Zellen mit abgezählten einzelnen Ionen. Als letztes Beispiel wird die Anwendung hochfokussierter Ionenstrahlen für die Mikrotomographie gezeigt. Abschließend folgt eine zusammenfassende Bewertung der vorgestellten Anwendungen mit einem Ausblick auf weitere Anwendungen und methodische Entwicklungen. Der Arbeit sind die relevanten Veröffentlichungen mit Beteiligung des Autors als Anhang beigefügt
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Joseph, Michael L. "A Geochemical Analysis of Fulgurites: from the inner glass to the outer crust." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4093.
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Cloud-to-ground lightning strikes produce natural glasses on the surface of the Earth, called fulgurites. These natural glasses are tubular in shape with a central void surrounded by an inner glass, and the inner glass is surrounded by an outer crust or toasted region. Previous studies report different kinds of melts existing in several different types of fulgurites; however, little to no chemical data has been collected that tracks chemical variations from the inner glass to the outer crust of a fulgurite. This study uses microprobe and laser ablation inductively coupled plasma mass spectrometer analytical techniques to collect transects of chemical composition from the inner glass to the outer crust of eleven fulgurites. Five of the eleven fulgurite samples show a well-mixed, volatile-depleted inner glass, enclosed in a poorly mixed volatile enriched outer melt, suggesting that these fulgurites formed from the vaporization and condensation of materials on the inner fulgurite wall. The remaining six fulgurites show poorly mixed melts in both the inner glass and outer crust regions, and most likely originated as lightning-produced melting phenomena. These data suggest that certain enigmatic natural glasses, such as Edeowie, Dakhleh and other unknown desert glasses, may be lightning-produced, in contrast to the meteorite burst or impact related origins that have commonly been propounded.
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Yu, Chak Chung Andrew. "Electron microscopy studies of magnetic tunnel junctions." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302402.
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Reinert, Tilo. "Ionenstrahluntersuchungen am Gelenkknorpel." Doctoral thesis, Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-197688.
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Knorpel ist ein kompliziertes System aus einem kollagenen Netzwerk, gefüllt mit wasserbindenden Makromolekülen (Proteoglykanen) und darin eingebetteten Zellen. Störungen in den komplexen Wechselbeziehungen können zur Gefährdung der strukturellen Integrität des Knorpels führen. Die hochauflösende Magnetresonanztomographie (NMR-Mikroskopie) kann über die Analyse der Signalintensität interne Knorpelstrukturen darstellen (hypo- und hyperintense Zonen).
Mit Hilfe ionenmikroskopischer Analysemethoden (PIXE, RBS, ERDA) wurden im Knorpel (femorale und tibiale Kondyle des Hausschweins) im Querschnitt die zweidimensionalen Verteilungen der Knorpelelemente (H, C, N, O, P, S, Cl, K und Ca) aufgenommen sowie die Konzentrationen in ausgewählten Zonen bestimmt. Ergänzend wurde mit STIM die Dichteverteilung im Knorpel untersucht. Es gelang auch mit STIM, erstmalig kollagene Fasern in ihrer, bis auf den Wasserentzug natürlichen, Umgebung im Knorpel und damit unverändert in ihrer Anordnung sichtbar zu machen (keine chemische Demaskierung nötig).
Die Ergebnisse wurden mit NMR- und polarisationsmikroskopischen Untersuchungen verglichen und in ihrem Zusammenhang mit den histologischen Knorpelzonen diskutiert. In den NMR-hypointensen Zonen fanden sich eine erhöhte Chlorkonzentration und punktförmige Calciumanreicherungen. Diese Zonen waren (im gefriergetrockneten Zustand) durch eine, bis zu einem Faktor vier höhere Dichte gekennzeichnet, die im maximalen Gehalt der Matrixelemente, H, C, N, O, (höchste Kollagendichte) begründet liegt. Im tibialen Knorpel konnten in der NMR-hypointensen Zone radial verlaufende einzelne Kollagenfasern nachgewiesen werden. Im femoralen Knorpel wurden in dieser Zone keine Einzelfasern nachgewiesen. Es deutete sich eine tubuläre Anordnung der Kollagenfasern an. In der hypertrophen Zone zeigten sich hohe Konzentrationen an Phosphor (Zellorganellen), Schwefel (Proteoglykane), Kalium (alkalisches Milieu) und Calcium (Vorstufe der Kalzifizierung). Die Chlorkonzentration hatte dort ihr Minimum. In dieser Zone verlaufen die Kollagenfasern radial und münden senkrecht in den Kalkknorpel. In der Tangentialfaserschicht wurde eine erhöhte Konzentration an Calcium und Phosphor beobachtet (Einlagerung von Calciumphosphaten). In dieser Zone wurden tangential verlaufende Kollagenfasern und ihr Übergang zur stärkeren Vernetzung mit teilweise arkadenförmiger Überstruktur sichtbar gemacht.
Zur genaueren Aufklärung der dreidimensionalen Anordnung der Kollagenen Strukturen wurden erste Experimente zur STIM-Tomographie durchgeführt.
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Fearn, Sarah. "A SIMS based bevel-image technique for the analysis of semiconductor materials." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312125.
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Smith, Richard W. "A study of small molecule ingress into planar and cylindrical materials using ion beam analysis." Thesis, University of Surrey, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390579.
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Lafuente, B., R. T. Downs, M. J. Origlieri, K. J. Domanik, R. B. Gibbs, and M. S. Rumsey. "New data on hemihedrite from Arizona." MINERALOGICAL SOC, 2017. http://hdl.handle.net/10150/626454.
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Hemihedrite from the Florence Lead-Silver mine in Pinal County, Arizona, USA was first described and assigned the ideal chemical formula Pb10Zn(CrO4)(6)(SiO4)(2)F-2, based upon a variety of chemical and crystal-structure analyses. The primary methods used to determine the fluorine content for hemihedrite were colorimetry, which resulted in values of F that were too high and inconsistent with the structural data, and infrared (IR) spectroscopic analysis that failed to detect OH or H2O. Our reinvestigation using electron microprobe analysis of the type material, and additional samples from the type locality, the Rat Tail claim, Arizona, and Nevada, reveals the absence of fluorine, while the presence of OH is confirmed by Raman spectroscopy. These findings suggest that the colorimetric determination of fluorine in the original description of hemihedrite probably misidentified F due to the interferences from PO4 and SO4, both found in our chemical analyses. As a consequence of these results, the study presented here proposes a redefinition of the chemical composition of hemihedrite to the ideal chemical formula Pb10Zn(CrO4)(6)(SiO4)(2)(OH)(2). Hemihedrite is isotypic with iranite with substitution of Zn for Cu, and raygrantite with substitution of Cr for S. Structural data from a sample from the Rat Tail claim, Arizona, indicate that hemihedrite is triclinic in space group P (1) over bar, a = 9.4891(7), b = 11.4242(8), c = 10.8155(7) angstrom, alpha = 120.368(2)degrees, ss = 92.017(3)degrees, gamma = 55.857(2)degrees, V = 784.88(9) angstrom(3), Z = 1, consistent with previous investigations. The structure was refined from single-crystal X-ray diffraction data to R-1 = 0.022 for 5705 unique observed reflections, and the ideal chemical formula Pb10Zn(CrO4)(6)(SiO4)(2)(OH)(2) was assumed during the refinement. Electron microprobe analyses of this sample yielded the empirical chemical formula Pb-10.05(Zn0.91Mg0.02)(Sigma) (= 0.93) (Cr5.98S0.01P0.01)(Sigma = 6.00) Si1.97O34 H-2.16 based on 34 O atoms and six (Cr + S + P) per unit cell.
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Gauthiez, Putallaz Laure. "Tracing fluids during medium to ultra-high pressure metamorphism: insights by combined in situ oxygen isotopes and trace element analysis." Phd thesis, Canberra, ACT : The Australian National University, 2017. http://hdl.handle.net/1885/157028.
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Fluids are an essential component of tectonic and metamorphic processes such as subduction and crustal anatexis. Fluids are elusive to trace as they commonly escape high-pressure rocks. This study uses oxygen isotopes to identify fluid influxes in metamorphic rocks and tie them to geologic events, measuring δ18O in situ by ion microprobe in garnet, zircon, apatite, monazite and lawsonite. New method developments are presented for δ18O analyses by Sensitive High Resolution Ion MicroProbe: (i) in apatite, a precision of 0.2‰ (1σ) is achieved; diffusion modelling shows that apatite is expected to preserve oxygen isotope signatures from 400-450°C and below; (ii) a matrix correction scheme is derived for monazite oxygen isotope measurement, allowing a precision of 0.35‰ (1σ); (iii) rutile oxygen isotope measurements yield major orientation effects. Fluid pulses generated by prograde dehydration reactions are investigated in the ultra-high-pressure Dora Maira whiteschists, Italy. Rare-earth-element abundances indicate prograde monazite and zircon growth (pre-garnet 34.5±0.7 Ma, 6.4‰ and syn-garnet at 34.9±0.4 Ma, 6.2 to 6.7‰), which are linked to dehydration reactions using thermodynamic modelling. This allows drawing a P-T-time-fluid path that implies that (i) prograde subduction from 25 to 45 kbar occurred within a couple of My (minimum burial rate of 2 cm/yr); (ii) high-pressure fluids were of internal origin and metasomatism likely have occurred at a rifting phase before subduction. Four phases of fluid circulations are identified in the high-pressure low-temperature lawsonite eclogites and blueschists of the Tavşanlı zone, Turkey. The Halilbağı unit is an oceanic complex containing various sediments and serpentinite together with 222±5 Ma MORB and 123±3 Ma OIB lithologies (zircon U-Pb, whole-rock major and trace elements). The sequence was thoroughly altered and mechanically mixed at the seafloor and in the accretionary prism, leading to overall high whole-rock δ18O of 11.0-17.0‰ for metabasites. Garnet, apatite and lawsonite are zoned in δ18O in samples across the unit, with contrasts of 7‰ in a MORB eclogite (garnet core: 6.3‰, rim: 13‰) and 3‰ in an impure quartzite (apatite core: 19.5‰, rim: 17‰). Petrographic and trace element evidence allow identifying localised prograde-peak fluid influx, and homogenisation of oxygen isotopes and Sr/Pb at the start of retrogression by pervasive fluid circulation across the unit. Heavy δ18O signatures (WR: 11.8 to 13.6‰) were measured in Eoarchaean metasediments from the Isua supracrustal belt, Greenland. The sources of the sediments were mantle-derived boninites (mafic component) and andesites (felsic component, detrital/volcanic zircons dated at 3709 Ma,δ18O 5.3‰). Three garnet growth zones record high δ18O (9 to 10‰), in equilibrium with the whole-rock. Rare-earth-element and petrographic evidence allow identifying a higher-pressure signature in the high- δ18O garnet, which can be linked to a 3690-3660 Ma tectonic event. The elevated δ18O signature in the metasediments thus originated from surficial processes (e.g. weathering) before 3690Ma. Melting of such heavy-δ18O amphibolite-facies sediments could represent a source for early Archean high-δ18O magmas and zircons. The combination of oxygen isotope and trace element microanalysis in zoned minerals proves a powerful tool for uncovering multistage minor and major fluid infiltration events in metamorphic rocks.
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Rowan, Fraser S. "A study of the effects of oxygen environment on the stoichiometry, phase assemblage and stability of BiSCCO 2212 and 2201 using EPMA." Thesis, University of Aberdeen, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369139.
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A method of performing accurate oxygen analysis on cuprate based superconducting materials was established using electron probe micro analysis (EPMA). A range of YBa2Cu3Oδ ceramics with varying oxygen concentration were used to test the method. Using YBCO as a reference material, a suitable standard for oxygen analysis of Bi2Sr2CaCu2Oδ (BiSCCO-2212) materials was obtained. This standard was used to perform full elemental analysis of a range of BiSCCO-2212 crystals, post annealed in pO2's between 10-5-2atm. When the average Cu valence of each crystal was calculated and plotted as a function of the critical temperature (Tc) for each crystal, it was shown that BiSCCO-2212 materials conformed to the 'universal' trend illustrated by most other HTS and did not exhibit anomalous behaviour as had been previously believed. The phase assemblage and superconducting properties of BiSCCO-2212 Ag-clad multifilamental wires, prepared using the powder-in-tube (PIT) method by BICC, were studied as a function of a time/temperature profile. pO2 of the processing atmosphere was found to be the predominant factor in determining the stoichiometry of the 2212 phase within wires. The phase assemblage is not simply a function of pO2 as previously believed and can be controlled, in part, by the post annealing temperature. Homogenisation of the phase assemblage in BiSCCO-2212 Ag-clad wires can be achieved by prolonged heating (96hrs) at an appropriate temperature. An investigation into the 10K superconducting BiSCCO phase has shown the Sr-rich solid solution to extend towards the ideal stoichiometry of 2:2:1 (Bi:Sr:Cu) with increasing pO2. Using a combination of high pO2 (60atm) to achieve the appropriate Bi:Sr stoichiometry followed by post annealing in N2 to adjust the oxygen content, it was possible to prepare single-phase ceramics of stoichiometry Bi2.11(2)Sr1.90(2)Cu0.99(2)Oδ with a Tc=10.5K(5).
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Devès, Guillaume. "Analyse chimique quantitative à haute résolution spatiale par microsonde et nanosonde nucléaires." Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14084/document.
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Etudier le rôle des éléments traces à l’échelle cellulaire requiert des outils analytiques de pointe. Nous avons développé une nouvelle méthodologie précise de la répartition des éléments chimiques cellulaires à partir d’une combinaison des méthodes d’analyse par faisceaux d’ions PIXE, RBS et STIM. Cette méthodologie s’appuie fortement sur le développement d’un logiciel (Paparamborde) pour le traitement quantitatif des expériences STIM. La validité de cette méthode ainsi que ses limites sont discutées. La méthode STIM-PIXE-RBS permet de quantifier la composition en éléments traces (µg/g) avec une incertitude de mesure évaluée à 19,8% dans des compartiments cellulaires de masse inférieure à 0,1 ng.Une des limites de la méthode réside dans le faible nombre d’échantillons analysables en raison à la fois du temps minimum nécessaire pour réaliser une acquisition et de l’accès limité aux plateformes d’analyse par faisceaux d’ions. C’est pourquoi nous avons également développé une base de données pour la capitalisation des compositions chimiques cellulaires (BDC4). Cette base de données s’inscrit dans la logique de l’utilisation de la composition chimique cellulaire comme un traceur de l’activité biologique, et doit permettre à terme de définir des compositions chimiques de référence pour les différents types cellulaires analysés.L’application de la méthodologie STIM-PIXE-RBS à l’étude de la toxicologie nucléaire du cobalt permet d’illustrer son intérêt en pratique. En particulier, l’analyse STIM s’avère indispensable dans le cas d’échantillons présentant une perte de masse organique au cours de l’analyse PIXE-RBSThe study of the role of trace elements at cellular level requires the use of state-of-the-art analytical tools that could achieve enough sensitivity and spatial resolution. We developed a new methodology for the accurate quantification of chemical element distribution in single cells based on a combination of ion beam analysis techniques STIM, PIXE and RBS. The quantification procedure relies on the development of a STIM data analysis software (Paparamborde). Validity of this methodology and limits are discussed here. The method allows the quantification of trace elements (µg/g) with a 19.8 % uncertainty in cellular compartments with mass below 0.1 ng.The main limit of the method lies in the poor number of samples that can be analyzed, due to long irradiation times required and limited access to ion beam analysis facilities. This is the reason why we developed a database for cellular chemical composition capitalization (BDC4). BDC4 has been designed in order to use cellular chemical composition as a tracer for biological activities and is expected to provide in the future reference chemical compositions for any cellular type or compartment.Application of the STIM-PIXE-RBS methodology to the study of nuclear toxicology of cobalt compounds is presented here showing that STIM analysis is absolutely needed when organic mass loss appears during PIXE-RBS irradiation
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Heiner, Brandon D. "Multi-Scale Neotectonic Study of the Clear Lake Fault Zone in the Sevier Desert Basin (Central Utah)." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/3840.
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A multi-scale high-resolution geophysical and geological study was conducted in the Sevier Desert, central Utah, found within the Colorado Plateau-Basin and Range Transition Zone. The region is marked by with Quaternary volcanics and faulting as young as 660 yr B.P., with many fault scarps thought to have the potential for 7+ magnitude earthquakes. Three locations within the Sevier Desert which represent three different tectonic expressions of possible faulting at the surface were selected. These include a location found within surface sedimentation, a location with surface sedimentation and sub-surface basalts and a location with basalts, at the surface with very limited sedimentation. A suite of geophysical data were obtained including the use of P-wave, SH-wave, ground-penetrating radar (GPR). Auger holes, microprobe glass analysis, and mapping information were also completed in order to constrain and gain a more complete understanding of the sub-surface structure. These data were used to determine if there are sub-surface expressions of the possible surface scarps and if all the faults within the fault zone have the same structural style. The possible surface fault expressions were found to be connected to sub-surface fault expressions but with differing results within both sediments and basalts. Our data show that a multi-scale approach is needed to obtain a complete view of tectonic activity. The area faulting in the Sevier Desert penetrates at depth involving multiple complex styles that include some faulting that cuts recent lava flows and some that do not. The evidence also indicates that in at least some area faulting was episodic and others may be single events having implications on level of activity and hazard.
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Höglund, Anny. "Towards a Tephrochronology for the Lakselv Peat Sequence in Finnmark County, Northern Norway." Thesis, Stockholms universitet, Institutionen för naturgeografi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-145154.
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To provide an increased breadth in the knowledge of tephra dispersal, this pilot study examines a peat core from Lakselv in Finnmark County in northern Norway. Peat samples are exposed to burning, HCl, density separation and polarized light microscopy. One sample from a depth of 37.5-40 cm was analysed using an electron microprobe analyser (EMPA). At least two tephra horizons were identified, one at a depth of 12.5-17.5 cm and one at 37.5-40 cm. The lower horizon shows a chemical composition similar to eruptives from Jan Mayen and São Miguel, Azores while the origin of the upper horizon is unknown as no geochemical analysis was performed for that depth.
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Kartouni, Abdelkarim. "Caractérisation analytique des premiers stades de l'oxydation du cuivre par méthodes non destructives." Rouen, 1993. http://www.theses.fr/1993ROUES059.
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L'association des méthodes optiques permet d'identifier les différentes espèces présentes dans les couches d'oxydes développées sur le cuivre depuis des épaisseurs de quelques nanomètres jusqu'à plusieurs micromètres. Les oxydes suivants: l'oxyde précurseur de Cu2O, de formule CuxO, Cu2O, Cu3O2 et CuO ont été caractérisés en spectroscopie UV-Vis-PIR en réflexion diffuse. Les défauts dans les oxydes cuivreux peuvent être identifiés par la spectroscopie de photoluminescence. Les premiers stades de l'oxydation du cuivre font intervenir un processus rapide suivant les réactions: 2Cu+1/2 O2Cu2O-3Cu2O+1/2 O2|2Cu3O2. Ainsi, à basse température (423° K) et pour les temps les plus longs, c'est l'oxyde Cu3O2 qui se forme. Dans le domaine de température 473-573° K, les résultats d'analyse démontrent clairement qu'il y a un changement périodique de la composition de la couche dans les premières étapes de l'oxydation. Les micrographies de ces couches, révèlent en extrême surface, un mélange de CuO et d'oxydes de cuivre (i). Pour les températures supérieures à 673° K, la couche a une structure multicouche CuO|Cu3O2|Cu2O|Cu
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Pampaloni, Francesco. "Force sensing and surface analysis with optically trapped microprobes." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965117421.
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SANTOS, CARLOS A. X. "Estudo do compósito 3Y-TZP/Sisub(2)Nsub(2)O obtido por sinterização sem pressão." reponame:Repositório Institucional do IPEN, 2006. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11430.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Lussier, Aaron J. "Zonation in tourmaline from granitic pegmatites & the occurrence of tetrahedrally coordinated aluminum and boron in tourmaline." Mineralogical Society of Great Britan and Ireland, 2008. http://hdl.handle.net/1993/5043.
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[1] Four specimens of zoned tourmaline from granitic pegmatites are characterised in detail, each having unusual compositional and/or morphologic features: (1) a crystal from Black Rapids Glacier, Alaska, showing a central pink zone of elbaite mantled by a thin rim of green liddicoatite; (2) a large (~25 cm) slab of Madagascar liddicoatite cut along (001) showing complex patterns of oscillatory zoning; and (3) a wheatsheaf and (4) a mushroom elbaite from Mogok, Myanmar, both showing extensive bifurcation of fibrous crystals originating from a central core crystal, and showing pronounced discontinuous colour zoning. Crystal chemistry and crystal structure of these samples are characterised by SREF, EMPA, and 11B and 27Al MAS NMR and Mössbauer spectroscopies. For each sample, compositional change, as a function of crystal growth, is characterised by EMPA traverses, and the total chemical variation is reduced to a series of linear substitution mechanisms. Of particular interest are substitutions accommodating the variation in [4]B: (1) TB + YAl ↔ TSi + Y(Fe, Mn)2+, where transition metals are present, and (2) TB2 + YAl ↔ TSi2 + YLi, where transition metals are absent. Integration of all data sets delineates constraints on melt evolution and crystal growth mechanisms.
[2] Uncertainty has surrounded the occurrence of [4]Al and [4]B at the T-site in tourmaline, because B is difficult to quantify by EMPA and Al is typically assigned to the octahedral Y- and Z-sites. Although both [4]Al and [4]B have been shown to occur in natural tourmalines, it is not currently known how common these substituents are. Using 11B and 27Al MAS NMR spectroscopy, the presence of [4]B and [4]Al is determined in fifty inclusion-free tourmalines of low transition-metal content with compositions corresponding to five different species. Chemical shifts of [4]B and [3]B in 11B spectra, and [4]Al and [6]Al in 27Al spectra, are well-resolved, allowing detection of very small (< ~0.1 apfu) amounts of T-site constituents. Results show that contents of 0.0 < [4]B, [4]Al < 0.5 apfu are common in tourmalines containing low amounts of paramagnetic species, and that all combinations of Si, Al and B occur in natural tourmalines.
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SANTOS, ROBINSON A. dos. "Estudo da influência de impurezas e da qualidade das superfícies em cristais de brometo de tálio para aplicação como um detector de radiação." reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/26818.
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Neste trabalho, cristais de TlBr foram crescidos e purificados pelo método de Bridgman Repetido, a partir de sais comerciais de TlBr, e caracterizados para serem usados como detectores de radiação à temperatura ambiente. Para avaliar a eficiência de purificação, estudos da diminuição da concentração de impurezas foram feitos após cada crescimento, analisando as impurezas traço por Espectrometria de Massas com Plasma (ICP-MS). Um decréscimo significativo da concentração de impurezas em função do número de purificações foi observado. Os cristais crescidos apresentaram boa qualidade cristalina de acordo com os resultados de análise por Difração de Raios X (DRX), boa qualidade morfológica e estequiometria adequada de acordo com os resultados de análise por MEV(SE) e MEV(EDS). Um modelo matemático definido por equações diferenciais foi desenvolvido para avaliar as concentrações de impurezas no cristal de TlBr e suas segregações em função do número de crescimentos pelo método de Bridgman. Este modelo pode ser usado para calcular o coeficiente de migração das impurezas e mostrou ser útil para prever o número necessário de repetições de crescimento Bridgman para atingir nível de pureza adequado para assegurar a qualidade do cristal como detector de radiação. Os coeficientes se segregação obtidos são parâmetros importantes para análise microestrutural e análise de transporte de cargas nos cristais detectores. Para avaliar os cristais a serem usados como detectores de radiação, medidas de suas resistividades e resposta à incidência de radiação gama das fontes de 241Am (59,5keV) e 133Ba (81 keV) foram realizadas. Essa resposta foi dependente da pureza do cristal. Os detectores apresentaram um avanço significativo na eficiência de coleta de cargas em função da pureza.
Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Bridges, Robert Leamon. "An Active Study of a Roller Coaster Project in Asia." Digital Commons @ East Tennessee State University, 2010. https://dc.etsu.edu/etd/1670.
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A roller coaster manufacturer became aware that improperly heat treated track couplings were sent to a construction site for assembly. Concerns were that suspect couplings might not meet the engineering specifications and could be vulnerable to sudden failure. A testing company in Oak Ridge, TN that specializes in in-situ and laboratory mechanical testing was contacted by the manufacturer for help in this endeavor. The construction company elected to enlist a local testing firm to perform field tests on the components instead of the company in Oak Ridge. The test methods used are incapable of providing quantitative results that could be measured to the engineering specifications, making it unlikely to identify anything but the worst material conditions. This study is an example that the need for accurate analysis is very important. The manufacturer reported that 60 couplings were replaced, but it is presently unknown how many should have been replaced.
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El, Farsy Abderzak. "Détermination des fonctions de distribution des flux des espèces neutres et ionisées en procédé HiPIMS et corrélations avec les couches minces de type TiN déposées." Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0085.
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La thèse s’inscrit dans la problématique du dépôt de couches minces en procédés de pulvérisation réactive cathodique magnétron continu basse puissance (R-DC) et pulsé haute puissance (R-HiPIMS). Le mode réactif consiste à ajouter, dans l’argon, un gaz réactif tels que l’oxygène ou l’azote. Les oxydes et les nitrures ont de très nombreuses applications industrielles. Néanmoins, les exigences des nouvelles applications nécessitent de mieux comprendre, contrôler et maîtriser les processus fondamentaux gouvernant le transport de la matière pour optimiser ces procédés plasmas. L’objectif principal de cette thèse est d’étudier le transport des atomes pulvérisés de titane (Ti) en mélange Ar/N2 et d’établir des corrélations avec les propriétés des dépôts de type TiN. La fluorescence induite par diode laser (résolue en temps dans le cas du procédé HiPIMS) a été développée pour mesurer les fonctions de distribution en vitesse des atomes neutres Ti à l’état fondamental en fonction de la pression, de la distance par rapport à la cible et du mélange gazeux. Le degré de liberté supplémentaire qu'offre la dimension temporelle du plasma HiPIMS a permis de caractériser leur cinétique de transport en ayant la possibilité de séparer les temps caractéristiques des différents processus, et de mettre en évidence trois populations d’atomes (énergétique, quasi-thermalisée et thermalisée). Les fonctions de distribution en énergie des ions Ti+ ont été mesurées par spectrométrie de masse et des hypothèses sont proposées pour pouvoir expliquer les quatre populations identifiées. Enfin, les couches minces déposées ont été analysées par MEB, DRX et microsonde de CastaingThe growth of thin layers in reactive-direct current magnetron sputtering (R-DC) and reactive-high power impulse magnetron sputtering (R-HiPIMS) processes is the general framework of this PhD. Reactive processes consist in the addition, in argon gas, of a reactive gas such as oxygen or nitrogen, and allow the deposition of oxides and nitrides which have many industrial applications. Nevertheless, the high level of expectations regarding new applications requires a better understanding, controlling, mastering of basic processes governing atoms transport in the view of process optimization. The main goal of this PhD is to study the transport of sputtered titanium atoms (Ti) in Ar/N2 gas mixture and to establish correlations with TiN film properties. Tunable diode laser induced fluorescence technique (time resolved in the case of HiPIMS process) has been developed in order to measure velocity distribution functions of neutral Ti atoms at the ground state, function of the pressure, the distance from the target and the gas mixture. In HiPIMS, the additional degree of freedom, given by time dimension, allowed to characterize their kinetic of transport while at the same time providing the possibility to separate characteristic time scales of different processes. Three atoms populations have been highlighted (energetic, quasi-thermalized and thermalized ones). Energy distribution functions of Ti+ ions have been measured using mass spectrometry and four populations have been observed and explained. Finally, deposited thin films have been analyzed by means of SEM, XRD and electron microprobe methods
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El, Farsy Abderzak. "Détermination des fonctions de distribution des flux des espèces neutres et ionisées en procédé HiPIMS et corrélations avec les couches minces de type TiN déposées." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0085.
Full textAbstract:
La thèse s’inscrit dans la problématique du dépôt de couches minces en procédés de pulvérisation réactive cathodique magnétron continu basse puissance (R-DC) et pulsé haute puissance (R-HiPIMS). Le mode réactif consiste à ajouter, dans l’argon, un gaz réactif tels que l’oxygène ou l’azote. Les oxydes et les nitrures ont de très nombreuses applications industrielles. Néanmoins, les exigences des nouvelles applications nécessitent de mieux comprendre, contrôler et maîtriser les processus fondamentaux gouvernant le transport de la matière pour optimiser ces procédés plasmas. L’objectif principal de cette thèse est d’étudier le transport des atomes pulvérisés de titane (Ti) en mélange Ar/N2 et d’établir des corrélations avec les propriétés des dépôts de type TiN. La fluorescence induite par diode laser (résolue en temps dans le cas du procédé HiPIMS) a été développée pour mesurer les fonctions de distribution en vitesse des atomes neutres Ti à l’état fondamental en fonction de la pression, de la distance par rapport à la cible et du mélange gazeux. Le degré de liberté supplémentaire qu'offre la dimension temporelle du plasma HiPIMS a permis de caractériser leur cinétique de transport en ayant la possibilité de séparer les temps caractéristiques des différents processus, et de mettre en évidence trois populations d’atomes (énergétique, quasi-thermalisée et thermalisée). Les fonctions de distribution en énergie des ions Ti+ ont été mesurées par spectrométrie de masse et des hypothèses sont proposées pour pouvoir expliquer les quatre populations identifiées. Enfin, les couches minces déposées ont été analysées par MEB, DRX et microsonde de CastaingThe growth of thin layers in reactive-direct current magnetron sputtering (R-DC) and reactive-high power impulse magnetron sputtering (R-HiPIMS) processes is the general framework of this PhD. Reactive processes consist in the addition, in argon gas, of a reactive gas such as oxygen or nitrogen, and allow the deposition of oxides and nitrides which have many industrial applications. Nevertheless, the high level of expectations regarding new applications requires a better understanding, controlling, mastering of basic processes governing atoms transport in the view of process optimization. The main goal of this PhD is to study the transport of sputtered titanium atoms (Ti) in Ar/N2 gas mixture and to establish correlations with TiN film properties. Tunable diode laser induced fluorescence technique (time resolved in the case of HiPIMS process) has been developed in order to measure velocity distribution functions of neutral Ti atoms at the ground state, function of the pressure, the distance from the target and the gas mixture. In HiPIMS, the additional degree of freedom, given by time dimension, allowed to characterize their kinetic of transport while at the same time providing the possibility to separate characteristic time scales of different processes. Three atoms populations have been highlighted (energetic, quasi-thermalized and thermalized ones). Energy distribution functions of Ti+ ions have been measured using mass spectrometry and four populations have been observed and explained. Finally, deposited thin films have been analyzed by means of SEM, XRD and electron microprobe methods
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Auclair, Gilles. "Processus de métallogénèse dans les amas sulfurés océaniques : Contribution à l'étude du comportement des éléments chalcophiles dans les processus hydrothermaux." Brest, 1988. http://www.theses.fr/1988BRES2001.
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Etude des parametres d'analyse de se, as, co, cd et ag dans les sulfures cpy, py, sp, iss, po conduisant a une amelioration du rapport signal-bruit et des precisions d'analyse. Analyse des sulfures par fluorescence x suivie d'analyse a la microsonde permettant de comprendre le comportement des elements trace au cours du processus de maturation d'un depot hydrothermal. On montre que les parageneses rencontrees different selon la situation du depot, la temperature. L'etude des conditions physico-chimiques de depot montre que les fluides peuvent subir une evolution et un remelange en toutes proportions lors de leur remontee a travers la croute oceanique. On replace les episodes hydrothermaux dans les cycles volcano-tectoniques et on propose une explication des variabilites mineralogiques et geochimiques des differents depots
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Amri, Noureddine. "Etude métallurgique des systèmes Fe-Nd, Fe-Dy et Fe-Nd-Dy : existence et stabilité de phases." Rouen, 1993. http://www.theses.fr/1993ROUES041.
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La formation de la phase métastable A1 dans les alliages Fe-Nd solidifiés de différentes façons est étudiée. Sa composition chimique estimée grâce à la microsonde électronique est très riche en fer (65 à 70% at. Fer). Son domaine d'existence, sa fraction volumique ainsi que sa cinétique de transformation en Nd2Fe1#7, sont fortement liés à la vitesse de solidification et à la composition de l'alliage. La substitution de l'Al au Fe dans la phase Nd5Fe1#7 se fait d'une manière indirecte à travers la réaction péritectoïde de la phase Nd2Fe1#7 (avec l'aluminium en substitution au fer). La phase nommée a#2 (Nd5Fe1#7 avec Al en substitution) est totalement différente de la phase (phase stable dans le ternaire Fe-Nd-Al). L'influence de la substitution de l'Al dans les phases A1 et Nd2Fe1#7 est également étudiée. Dans l'alliage ternaire Fe-Nd-Dy, la phase A1 est complètement supprimée. La phase Nd5Fe1#7 accepte du dysprosium en substitution au Nd mais en faible quantité, car au-delà d'un certain taux de Dy dans la phase, elle est déstabilisée au bénéfice de la phase de laves pseudo-binaire Fe2 (Nd, Gy) parfaitement stable
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Gautier, Eric. "Etude des propriétés structurales et physiques de la famille d'oxycarbonates supraconducteurs (Cu,C)Ba2Ca(n-1)CunOy." Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE10281.
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Parmi les nouveaux materiaux supraconducteurs a hautes temperatures critiques (tc) decouverts ces dernieres annees, les cuprocarbonates de formule generale (cu,c)ba#2ca#n#-#1cu#no#y presentent l'avantage d'avoir des tc tres elevees (jusqu'a 120 k) sans contenir de cations toxiques tels que bi, ti, ou hg. L'une de leurs caracteristiques est d'etre synthetises sous haute pression (8 gpa) et a haute temperature (1200c). La synthese des composes a ete optimisee, d'une part grace a un meilleur controle de la quantite de carbone, d'autre part a la prise en compte du taux d'oxydation du precurseur. Les substitutions cationiques (ca, >y et c, >n) ont ensuite ete etudiees ainsi que le role de la stoechiometrie en oxygene. Ceci a ete couple a l'etude des proprietes physiques par mesure de susceptibilite magnetique alternative et de resistivite sous pression. Le caractere surdope des echantillons apres synthese a pu etre mis en evidence. Les reductions ont permis d'atteindre le dopage optimal pour lequel tc=120k dans le terme (cu,c)ba#2ca#2cu#3o#y. La structure de ces composes suit le schema general des cuprates supraconducteurs avec des plans conducteurs (plan cuo#2) et des reservoirs de charges. La presence d'impuretes non identifiees n'a pas permis de determiner la structure en details a partir de donnees de diffraction des rayons x ou des neutrons. Il semble cependant que les plans cuo#2 externes soient un peu ondules du fait de la presence alternee de cu et c dans le reservoir de charges (plan de base). L'utilisation de techniques locales telles que la microscopie electronique couplee a l'analyse par spectroscopie eels ont permis de mettre en evidence la presence de groupement co#3 formant un arrangement alterne avec les atomes de cuivre dans le plan de base, l'existence d'un atome d'oxygene mobile entre deux atomes de cuivre dans ce meme plan, lui conferant un environnement plan carre comme dans yba#2cu#3o#7. Differents types de defauts tels qu'intercroissances de differents membres de la serie, absence locale de carbone sont apparus. Enfin, une determination structurale a l'echelle d'un cristallite (1 m) a ete abordee en utilisant les intensites mesurees sur les cliches de diffraction electronique, a l'aide d'une approche de type patterson.
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Sircombe, Keith Nicholas. "Detrital mineral SHRIMP geochronology and provenance analysis of sediments in Eastern Australia." Phd thesis, 1997. http://hdl.handle.net/1885/145909.
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Chan, Ho-yin. "Polycrystalline CVD diamond probes for use in in vivo and in vitro neural studies." Diss., 2008. http://proquest.umi.com/pqdweb?did=1680063551&sid=1&Fmt=2&clientId=3552&RQT=309&VName=PQD.
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Thesis (Ph. D.)--Michigan State University. Electrical Engineering, 2008.Title from PDF t.p. (Proquest, viewed on Aug. 17, 2009) Includes bibliographical references (p. 120-135). Also issued in print.
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Cross, Andrew Joseph. "SHRIMP U-Pb xenotime geochronology and its application to dating mineralisation, sediment deposition and metamorphism." Phd thesis, 2009. http://hdl.handle.net/1885/109400.
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Diagenetic and hydrothermal xenotime typically occurs in rocks as tiny crystals (≤20
μm), either individually or as outgrowths on a zircon substrate. Currently only large
radius ion microprobes such as the SHRIMP or Cameca 1270/1280 have the high
sensitivity and spatial resolution necessary to analyse these crystals for U-Th-Pb
isotopes. However, such analyses are prone to significant matrix effects (ME) related
to the large natural range of U (0 to ~9 wt%) and REE (ΣREE: -12 to 22 wt%)
abundances in xenotime. Consequently, the ²⁰⁶PbP²³⁸U calibration procedure for
xenotime differs significantly from that employed for SIMS dating of zircon.
Contrasts in U, and to a lesser extent IREE, contents between the primary calibration
standard and unknown xenotime can result in SHRIMP 2⁰6Pb/218U-2⁰8Pb/232Th ME of
up to -20%. The matrix correction technique developed requires the concurrent
analysis of three xenotime standards with a range of U and IREE concentrations on a
session-by-session basis. The ²⁰⁶rb/²³⁸U-²⁰⁸Pb/²³²Th ME is monitored by the analysis
of two secondary standards, a high ΣREE xenotime (BS l) and a high U xenotime
(Z6413). Additionally, the chemical composition of each spot is determined by
EPMA (WDS) prior to SHRIMP analysis. Each spot is corrected for ME by defining a
series of simultaneous equations that relate the fractional ²⁰⁶Pb/²³⁸U-²⁰⁸ Pb/²³²Th
ME of the secondary standards to their U and ΣREE concentration contrasts with the
primary calibration standard (MG1). On average, every 1 wt% contrast in U between
the primary calibration standard and the unknown results in a ~11.9% difference in
the ²⁰⁶Pb/²³⁸U and ²⁰⁸Pb/²³²Th ratios, whereas a 1wt% contrast in REE results in a
difference in the ²⁰⁶Pb/²³⁸U and ²⁰⁸Pb/²³²Th ratios of ~0.9%.
SHRIMP RG was used for these experiments because the analyses on that instrument
are not prone to the molecular interferences or 'scattered ions' that affect the ²⁰⁴Pb
peak when xenotime is analysed on SHRIMP II. Matrix uncorrected ²⁰⁶Pb/²³⁸ U ratios
were determined from the raw ²⁰⁶Pb/²7°(UO₂⁺) ratios as suggested for zircon analyses
by Stem & Amelin (2003). Additionally, matrix uncorrected ²⁰⁸Pb/²³²Th ratios were
determined from the raw ²⁰⁸Pb/²⁴⁸ (ThO⁺) ratios, however, this calibration appears to
only be effective for xenotime with >~1000 ppm Th.The technique developed is broadly similar to the SHRIMP xenotime U-Th-Pb
correction procedure proposed by Fletcher et al. (2004). Whereas Fletcher and others
related SHRIMP xenotime ²⁰⁶Pb/²³⁸U-²⁰⁸Pb/²³²Tu ME to contrasts in U, Th and
ΣREE, 1his study indicates 1hat the effect of Th on 1he ²⁰⁶Pb/²³⁸U-²⁰⁸ Pb/²³ Tu ME is
minor to insignificant. It appears likely that for xenotime, it is the matrix sensitivity of
the emission of the Pb+ secondary ions, not U or Th species that is the principal cause
of the ²⁰⁶Pb/²³⁸U-²⁰⁸Pb/²³²Th ME. Using the new matrix correction procedures
developed here, it is possible to measure ²⁰⁶ Pb/²³⁸U and ²⁸Pb/²³²Th ages of
Phanerozoic xenotime with an accuracy and precision of about 2% (95% confidence).
Three application studies of SHRIMP U-Pb xenotime geochronology using the
matrix correction procedures developed were undertaken as a part of this study as
well as a SHRIMP U-Pb detrital zircon study of the principal sedimentary units
within the Tanami Basin, central Australia.
SHRIMP U-Pb analyses of xenotime that occurs as outgrowths on detrital zircon
from a sample of quartzite from the Serra da Mesa Group, central Brazil, has the same
Neoproterozoic age within error to that of SHRIMP U·-Pb monazite analyses from
the same sample, both giving ²⁰⁶Pb/²³⁸U ages of ~570 Ma. This latest Neoproterozoic
age may be related to metamorphism associated with the final stages of the Brasiliano
Orogeny. Further U-Pb studies are required on oilier rocks from this region to
establish its regional extent. The identical SHRIMP ²⁰⁶Pb/²³⁸U ages for both monazite
and xenotime in this study lend strong support to the matrix correction protocols
developed.
SHRIMP U-Pb analyses of hydrothermal xenotime from the Callie and Coyote Au
deposits in the Tanami region has demonstrated that they formed between ~1.81 and
~1.80 Ga. The -1.81 Ga age for the Callie deposit contrasts with the results from an
earlier 40 Ar/39 Ar study of hydrothermal biotite from the Callie deposit by Fraser
(2002), which suggested that mineralisation occurred at ~ 1.72 Ga. Mineralisation
between ~1.81 and ~1.80 Ga occurring in the Tanami region is coincident with the
~1.81 to ~1.79 Ga Stafford event which was a period of widespread magmatism
across much of the North Australia Craton in which Scrimgeour (2006) suggested was linked to a long-lived north-dipping subduction system active at the south-east margin
of the craton.
A preliminary isotopic dating investigation of the Molyhil scheelite-molybdenite
skarn deposit in the north-eastern Arunta region, central Australia has determined that
it formed from fluids associated with the crystallisation of the Marshall Granite
during the ~1. 73 to ~1. 72 Ga Strangways Oregeny. Rhenium-Osmium dating of ore
stage molybdenite has an age of 1720.7 ± 5.9 Ma which is also coincident wifh skarn related
hornblende which has an ⁴⁰Ar/⁴⁰Ar age between ~1.72 and ~1.73 Ga (G.
Fraser, unpublished data; Geoscience Australia). Importantly for this study is that one
of the xenotime grains has a concordant SHRIMP U-Pb ²⁰⁷Pb²⁰⁶Pb age of 1714 ± 26
Ma which is well within error of the ages determined by the other two isotopic
methods adding further support to the SHRIMP U-Pb analytical protocols and
²⁰6Pb/²38U matrix correction techniques developed during this PhD. Younger
xenotime components from the Molyhil sample investigated have SHRIMP ²⁰⁶ Pb/²³⁸U
ages of ~760 Ma and ~650 Ma and probably crystallised in response to far-field
tectonothermal events.
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Reinert, Tilo. "Focussed MeV-Ion Micro- and Nano-Beams in the Life Sciences: Selected Applications." Doctoral thesis, 2008. https://ul.qucosa.de/id/qucosa%3A14510.
Full textAbstract:
This work presents the development of a sub-micron nuclear microprobe for applications in the life sciences. It includes quantitative trace element analysis with sub-micron spatial resolution, 2D- and 3D-microscopy of density distributions and the targeted irradiation of living cells with counted single ions. The analytical methods base on particle induced X-ray emission spectrometry (PIXE), Rutherford backscattering spectrometry (RBS), scanning transmission ion microscopy (STIM) and STIM-tomography. The specific development of the existing nuclear microprobe LIPSION led to an improved performance of the capabilities for trace element analysis. For sub-micron analysis the spatial resolution could be improved to 300 nm at a sensitivity of about 1 µg/g for
metal ions in biological matrices; for a resolution of 1 µm the sensitivity was improved to 200 ng/g (3 µmol/l).
This habilitation thesis comprises a short general introduction including the motivation to utilize focussed high energy ion beams, an overview on the applications and actual research fields. The introduction is followed by the basic principles of the equipments and analytical methods. An estimation of the limits of resolution for element analytical and single ion techniques is given for the Leipzig system. Thereafter, selected studies from different research areas are presented. The first presented application is a study from environmental air pollution research. It is demonstrated that the microscopic elemental analysis of single aerosol particles can be used to assess the contributions from different sources. A further example is the analysis of the distribution of nanoparticles in skin cross-sections for a risk assessment of the applications of nanosized physical UV-filters in cosmetic products. The risk assessment is followed by the micro-analysis of trace elements, especially of bound metal ions, in brain sections on the cellular and sub-cellular level. After this the application of focussed MeV ion beams in low dose radiobiological research is presented. Finally, the analysis of 3D-density distributions by proton micro-tomography is demonstrated. A summary concludes on the applications and gives an outlook to further applications and methodological developments. The appendix comprises the relevant publications of the author.Die vorliegende Arbeit etabliert für Anwendungen in den Lebenswissenschaften den Einsatz hochfokussierter MeV-Ionenstrahlen für nuklear-mikroskopische Methoden der quantitativen Spurenelementanalyse, der 2D- und 3D-Dichtemikroskopie sowie für die gezielte Bestrahlung einzelner lebender Zellen für radiobiologische Experimente. Zur Anwendung kamen die Methoden ortsaufgelöste Protonen induzierte Röntgenfluoreszenzanalyse (particle induced X-ray emission - PIXE), Spektrometrie rückgestreuter Ionen (Rutherford backscattering spectrometry - RBS) und Rastertransmissionsionenmikroskopie (scanning transmission ion microscopy - STIM). Durch eine gezielte Weiterentwicklung des bestehenden Ionenstrahlmikroskops, der Hochenergie Ionennanosonde LIPSION, konnte die Ortsauflösung für Spurenelementanalyse auf unter 300 nm verbessert werden, beziehungsweise die Sensitivität für Metallionen in biologischen Proben auf unter 200 ng/g (3 µmol/l) bei einer Ortsauflösung von 1 µm verbessert werden. Die Habilitationsschrift umfasst eine kurze allgemeine Einleitung einschließlich der Motivation für den Einsatz fokussierter MeV-Ionenstrahlen sowie einen Überblick über die Anwendungsgebiete und aktuellen Forschungsschwerpunkte. Danach werden kurz die Grundlagen der Technik und Methoden vorgestellt, gefolgt von einer Abschätzung der Auflösungsgrenzen für Elementanalysen und Einzelionentechniken. Danach werden ausgewählte Anwendungen aus verschiedenen Forschungsgebieten vorgestellt. Das erstes Beispiel ist aus der Umweltforschung. Es wird dargestellt, wie mittels ortsaufgelöster Elementspektroskopie eine Abschätzung der Feinstaubbelastung nach Beiträgen einzelner Verursacherquellen erfolgen kann. Dann folgt als Beispiel eine ortsaufgelöste Analyse der Verteilung von Nanopartikeln aus Sonnencremes in Hautquerschnitten zur Risikoabschätzung der Anwendungen von Nanotechnologie in kosmetischen Produkten. Desweiteren werden Studien der Spurenelementverteilung, speziell der von gebundenen Metallionen, in Hirnschnitten auf zellulärer und subzellulärer Ebene erläutert. Das anschließende Beispiel erläutert die Anwendung niedriger Energiedosen in der Radiobiologie anhand des Beschusses einzelner lebender Zellen mit abgezählten einzelnen Ionen. Als letztes Beispiel wird die Anwendung hochfokussierter Ionenstrahlen für die Mikrotomographie gezeigt. Abschließend folgt eine zusammenfassende Bewertung der vorgestellten Anwendungen mit einem Ausblick auf weitere Anwendungen und methodische Entwicklungen. Der Arbeit sind die relevanten Veröffentlichungen mit Beteiligung des Autors als Anhang beigefügt.
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Koteas, George Christopher. "Analysis of the gouldsboro pluton and the fehr granite: Understanding the scales of magmatic processes and partial melt generation from the deep to shallow crust." 2010. https://scholarworks.umass.edu/dissertations/AAI3427548.
Full textAbstract:
The heterogeneity of the continental crust has a first order control on the dynamics of plate tectonic processes and the compositions of the Earth in both time and space. Heterogeneity can be characterized at a variety of scales and in a multitude of tectonic environments, but it is the links between seemingly disparate tectonic settings and crustal levels that are critical in understanding construction of the continents. The focus of this dissertation work is to apply microtextural, microgeochemical, whole rock geochemical and traditional petrographic techniques to study features in both deep and shallow crustal igneous rocks. The goal of these efforts is to better understand the roles that magmatic processes, mafic-felsic magma interaction, and partial melting have on the evolution of continental crust. Two principal field areas were selected, the Gouldsboro pluton in coastal Maine and the Fehr granite in northern Saskatchewan, Canada, because they each represent end-members of the processes involved with the generation, modification, transport, and emplacement of magmas that build continental crust. Evidence for bimodal magmatism preserved in the Silurian age Gouldsboro pluton has led to a refined model for the construction of shallow crustal magma chambers. Research efforts focused on the Neoarchean Fehr granite and Paleoproterozoic Chipman dike swarm have contributed to the current understanding of the links between high temperature metamorphism (migmitization) and the production of new felsic magmas as well as the rheological and chemical influences of mafic-felsic magma interaction in the deep crust. The results of these combined field and laboratory efforts have demonstrated the important role of mafic-felsic magma interaction on the strength and composition of both deep and shallow continental crust and have contributed to the current understanding of the complex links between deep crustal heterogeneity and bimodal magmatism at shallow crustal levels.
42
Reinert, Tilo. "Ionenstrahluntersuchungen am Gelenkknorpel: Energiedispersive Röntgenspektrometrie, Rückstreuspektrometrie und Transmissionsionenmikroskopie (PIXE, RBS, STIM)." Doctoral thesis, 2001. https://ul.qucosa.de/id/qucosa%3A14506.
Full textAbstract:
Knorpel ist ein kompliziertes System aus einem kollagenen Netzwerk, gefüllt mit wasserbindenden Makromolekülen (Proteoglykanen) und darin eingebetteten Zellen. Störungen in den komplexen Wechselbeziehungen können zur Gefährdung der strukturellen Integrität des Knorpels führen. Die hochauflösende Magnetresonanztomographie (NMR-Mikroskopie) kann über die Analyse der Signalintensität interne Knorpelstrukturen darstellen (hypo- und hyperintense Zonen).
Mit Hilfe ionenmikroskopischer Analysemethoden (PIXE, RBS, ERDA) wurden im Knorpel (femorale und tibiale Kondyle des Hausschweins) im Querschnitt die zweidimensionalen Verteilungen der Knorpelelemente (H, C, N, O, P, S, Cl, K und Ca) aufgenommen sowie die Konzentrationen in ausgewählten Zonen bestimmt. Ergänzend wurde mit STIM die Dichteverteilung im Knorpel untersucht. Es gelang auch mit STIM, erstmalig kollagene Fasern in ihrer, bis auf den Wasserentzug natürlichen, Umgebung im Knorpel und damit unverändert in ihrer Anordnung sichtbar zu machen (keine chemische Demaskierung nötig).
Die Ergebnisse wurden mit NMR- und polarisationsmikroskopischen Untersuchungen verglichen und in ihrem Zusammenhang mit den histologischen Knorpelzonen diskutiert. In den NMR-hypointensen Zonen fanden sich eine erhöhte Chlorkonzentration und punktförmige Calciumanreicherungen. Diese Zonen waren (im gefriergetrockneten Zustand) durch eine, bis zu einem Faktor vier höhere Dichte gekennzeichnet, die im maximalen Gehalt der Matrixelemente, H, C, N, O, (höchste Kollagendichte) begründet liegt. Im tibialen Knorpel konnten in der NMR-hypointensen Zone radial verlaufende einzelne Kollagenfasern nachgewiesen werden. Im femoralen Knorpel wurden in dieser Zone keine Einzelfasern nachgewiesen. Es deutete sich eine tubuläre Anordnung der Kollagenfasern an. In der hypertrophen Zone zeigten sich hohe Konzentrationen an Phosphor (Zellorganellen), Schwefel (Proteoglykane), Kalium (alkalisches Milieu) und Calcium (Vorstufe der Kalzifizierung). Die Chlorkonzentration hatte dort ihr Minimum. In dieser Zone verlaufen die Kollagenfasern radial und münden senkrecht in den Kalkknorpel. In der Tangentialfaserschicht wurde eine erhöhte Konzentration an Calcium und Phosphor beobachtet (Einlagerung von Calciumphosphaten). In dieser Zone wurden tangential verlaufende Kollagenfasern und ihr Übergang zur stärkeren Vernetzung mit teilweise arkadenförmiger Überstruktur sichtbar gemacht.
Zur genaueren Aufklärung der dreidimensionalen Anordnung der Kollagenen Strukturen wurden erste Experimente zur STIM-Tomographie durchgeführt.
43
Elsenheimer, Donald William. "Development and application of laser microprobe techniques for oxygen isotope analysis of silicates and, fluid/rock interaction during and after granulite-facies metamorphism, Highland Southwestern Complex, Sri Lanka." 1992. http://catalog.hathitrust.org/api/volumes/oclc/28654261.html.
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Crowe, Douglas Edward. "Geochemistry of volcanogenic massive sulfide and high-grade Au granite-hosted ore deposits, southern Alaska ; and, Development and application of laser microprobe techniques for analysis of sulfur, carbon and oxygen isotope ratios." 1990. http://catalog.hathitrust.org/api/volumes/oclc/23277076.html.
Full textAbstract:
Thesis (Ph. D.)--University of Wisconsin--Madison, 1990.Typescript. Four plates on folded leaves in pocket. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
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Mphela, Nthabiseng. "Fundamental studies of the electrochemical and flotation behaviour of pyrrhotite." Diss., 2010. http://hdl.handle.net/2263/27256.
Full textAbstract:
Extensive research has shown that electrochemistry is one of the factors that govern the flotation of sulfide minerals. Flotation is often adversely affected by uncontrolled oxidation, which is also an electrochemical process. The interest in pyrrhotite recovery arose after observing that there is a substantial loss of PGM due to the depression of pyrrhotite and the subsequent loss of any PGMs associated with it. The first part of this study focuses on the influence of chemical composition and crystal structure on the electrochemical behaviour of pyrrhotite in a 0.05 M Na2B4O7 solution. Rest potential and polarisation resistance measurements, as well as anodic polarisation diagrams, showed that the magnetic 4C type pyrrhotite is anodically more reactive than the non-magnetic 6C type pyrrhotite. It was also shown in cathodic polarisation diagrams that the non-magnetic 6C type pyrrhotite is a better substrate for oxygen reduction and is less susceptible to oxidation. ToF-SIMS showed the formation of an oxide layer on the pyrrhotite surface after oxidation. In the second part of this work, the influence of galvanic interactions on the electrochemical behaviour of pyrrhotite in contact with pentlandite was investigated. It was observed that, under oxygen-saturated conditions, as the amount of pentlandite increases, the reactivity towards oxidation of the mixed mineral system is reduced. Impedance measurements showed a decrease in capacitance values, indicating the formation of a continuous oxide layer on the surface and an increase in oxide layer thickness with decreasing pentlandite content. Anodic polarisation diagrams showed that under oxygen-deficient conditions and in the low potential region, pentlandite behaves as an inert material and does not have an influence on the oxidation behaviour of pyrrhotite. Hence, the anodic activities of the different magnetic 4C type pyrrhotites from Sudbury Gertrude, Phoenix and Russia were compared. It was shown that the oxidation reactivity decreased in the following order: Sudbury Gertrude magnetic 4C pyrrhotite > Phoenix magnetic 4C pyrrhotite > Russian magnetic 4C pyrrhotite; it also varied according to location. In the transpassive region, higher anodic currents were observed on the mixed samples because both pentlandite and pyrrhotite reacts. The reactivity increased in the order: pure pyrrhotite (Russia) < medium-pentlandite (Sudbury Gertrude) < high-pentlandite (Phoenix). In the presence of potassium ethyl xanthate, there was no change in the initial anodic reactivities of the different pyrrhotites. The anodic polarisation diagrams of the pure and mixed samples showed a reduction in the maximum anodic peak current, suggesting the presence of xanthate on the surface, which hinders oxidation of the mineral surface. In addition, the influence of cleaning of oxidised pyrrhotite with gaseous carbon dioxide was studied, using electrochemical and microflotation measurements. Electrochemical measurements indicated that CO2 treatment resulted in depassivation of the oxidised surfaces; this was supported by ToF-SIMS measurements that demonstrated a reduction in the oxide layer thickness after CO2 treatment. Anodic polarisation diagrams showed a higher anodic peak current, indicating that the surface is more reactive. Gaseous carbon dioxide conditioning of oxidised pyrrhotite resulted in improved flotation response of pyrrhotite with the aid of copper activation and higher air flow rate. CopyrightDissertation (MEng)--University of Pretoria, 2010.
Materials Science and Metallurgical Engineering
unrestricted
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Pampaloni, Francesco [Verfasser]. "Force sensing and surface analysis with optically trapped microprobes / vorgelegt von Francesco Pampaloni." 2002. http://d-nb.info/965117421/34.
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HONG, DUAN-YOU, and 洪端佑. "Laser microprode and resonance ionization mass spectrometry for the analysis of constituents, isotopes and trace elements in solids." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/92429085639719529842.
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Matjie, Ratale Henry. "Sintering and slagging of mineral matter in South African coals during the coal gasification process." Thesis, 2008. http://upetd.up.ac.za/thesis/available/etd-11112008-125913.
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