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Bells Corners, Canada

Schumann D.,Fibics Incorporated | Schumann D.,University of Western Ontario | Hesse R.,McGill University | Hesse R.,Ludwig Maximilians University of Munich | And 2 more authors.
Clays and Clay Minerals | Year: 2014

Ultrathin sections of reference 2:1 layer silicates treated with octadecylammonium cations were examined using high-resolution transmission electron microscopy (HRTEM) to establish the layer structure. Hitherto, few HRTEM ultrathin-section data existed on the expansion behavior of smectite-group minerals with different interlayer-charge values. Without such information, the expansion behavior of both low-charge and high-charge smectite minerals cannot be characterized and the structures observed in HRTEM images of clay-mineral mixtures cannot be interpreted reliably. Reference smectite-group minerals (Upton, Wyoming low-charge montmorillonite; Otay, California high-charge montmorillonite; a synthetic fluorohectorite; and a Jeanne d'Arc Basin offshore Newfoundland clay sample) with a range of layer charge values were examined. To prevent possible intrusion of epoxy resin into interlayers during embedding, the clay samples were first embedded in epoxy, sectioned with an ultra microtome, and then treated with octadecylammonium cations before examination using HRTEM. Lattice-fringe images showed that lower-charge (<0.38 eq/O10(OH)2) 2:1 layers had 13 – 14 Å spacings, whereas higher-charge (>0.38 eq/O10(OH)2) 2:1 layers had 21 and 45 Å spacings. These differently expanded silicate layers can occur within the same crystal and an alternation of these layer types can generate rectorite-like structures. For comparison, clay samples were also treated with octadecylammonium before epoxy embedding and sectioning and then examined with HRTEM. These samples mostly had highly expanded interlayers due to epoxy intrusion in the interlayer space. The reference clay minerals embedded in epoxy resin, sectioned, and treated with octadecylammonium cations were used to characterize smectite-group minerals in a natural clay sample from the Jeanne d'Arc Basin, Eastern Canada. Smectite-group minerals in this sample revealed similar structures in lattice-fringe images to those observed in the pure reference clay samples. Rectorite-like structures observed in lattice-fringe images were in fact smectite crystals with short, alternating sequences of low-charge and high-charge smectite layers rather than illite-smectite (I-S) phases with expanded smectite layers and non-expanded 10 Å illite layers. © 2014, Publishing Technology.

Fuchs S.,McGill University | Schumann D.,Fibics Incorporated | Schumann D.,University of Western Ontario | Williams-Jones A.E.,McGill University | Vali H.,McGill University
Chemical Geology | Year: 2015

Uranium and gold-bearing pyrobitumen from the Carbon Leader Reef in the Witwatersrand Basin, South Africa, was investigated by high-resolution transmission electron microscopy. This study provides evidence for the in-situ growth of uraninite and anatase nanocrystals in the pyrobitumen, implying mobilization and concentration of uranium and titanium by formerly mobile liquid hydrocarbons. Individual nanocrystals of uraninite and anatase are pervasively distributed and locally isolated within the pyrobitumen matrix. Crystallization of uraninite and anatase led to the formation of complex nanocrystal aggregates by oriented attachment, in which anatase generally provided nuclei for the growth of uraninite. Single nanocrystals of curite occur locally in channel ways within masses of uraninite nanocrystals, consistent with later auto-oxidation of uraninite and limited release of water during hydrocarbon maturation. On the basis of evidence for the migration of liquid hydrocarbons in the Witwatersrand Basin and the presence of abundant uraninite and anatase nanoparticles in pyrobitumen, a new model is proposed for the transport and concentration of uranium (and titanium) in the Carbon Leader Reef. According to this model, liquid hydrocarbons that were circulating in the Witwatersrand Basin dissolved detrital U-Ti-bearing minerals and transported the uranium and titanium until thermal degradation immobilized the hydrocarbons by solidifying them as pyrobitumen. The latter process involved the release of volatiles and the destruction of bonds that may have held the uranium and titanium in solution, thereby inducing the growth of individual uraninite and anatase nanocrystals and the formation of complex nanocrystal aggregates within the pyrobitumen. © 2014 Elsevier B.V.

Burke K.B.,University of Newcastle | Luber E.J.,University of Alberta | Luber E.J.,Canadian National Institute For Nanotechnology | Holmes N.P.,University of Newcastle | And 6 more authors.
Journal of Electron Spectroscopy and Related Phenomena | Year: 2012

We present a simple knife-edge measurement of the STXM synchrotron X-ray beam width. The knife edge was constructed by ion beam milling a metallic glass alloy consisting of 60% gold, 20% nickel and 20% hafnium and was determined to be well-defined to within 2 nm by TEM. An asymmetric beam profile of 120 nm FWHM in the vertical direction and 150 nm FWHM in the horizontal direction was determined and was observed to depart from the expected Airy function profile. © 2012 Elsevier B.V.

Thompson W.,Carl Zeiss GmbH | Stern L.,Carl Zeiss GmbH | Wu H.,Carl Zeiss GmbH | Ferranti D.,Carl Zeiss GmbH | And 5 more authors.
Conference Proceedings from the International Symposium for Testing and Failure Analysis | Year: 2012

Sub-nanometer focused inert gas ions derived from a Gas Field Ion Source (GFIS) contain properties that can improve the dimensional and conductivity characteristics of ion beam deposited platinum circuit edit wiring. The following paper, presents ion interaction simulations that help provide insight into the factors which determine the ultimate wire width, resistivity, and metal deposition rates. An experimental result that has aided in the understanding of the primary wire width limiting mechanism is also presented. Finally, a description of the ion beam and precursor properties used for the platinum deposition is provided, a long with a discussion of the wire resistivity measurement technique and challenges. To conclude, the prospects for GFIS ion induced dielectric and metal deposition for circuit edit and nanofabrication applications are discussed. Copyright © 2012 ASM International® All rights reserved.

Fibics Incorporated | Date: 2006-03-14

Computer hardware and software used for operating charged particle beam instruments.

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