High-resolution electron microscopy observations

Flueli M, Buffat P A and Borel J P 1988 Real time observation by high resolution electron microscopy (HREM) of the coalescence of small gold particles in the electron beam Surf. Sc/. 202 343... 

High resolution electron microscopy has recently demonstrated the capability to directly resolve the atomic structure of surfaces on small particles and thin films. In this paper we briefly review experimental observations for gold (110) and (111) surfacest and analyse how these results when combined with theoretical and experimental morphological studies, influence the interpretation of geometrical catalytic effects and the transfer of bulk surface experimental data to heterogeneous catalysts. 

Electron diffraction performed with a parallel incident beam, i.e. Selected-Area Electron Diffraction is used to obtain good electron micrographs. The two-beam condition allows the observation of defects. SAED is also used in High-Resolution Electron Microscopy (HREM) to set a crystal to a zone axis so that the atomic columns are vertical in the microscope. SAED is very useful for the identification of phases and the... 

Lee SY, Jackson ML, Brown JL (1975a) Micaceous occlusions in kaolinite observed by ultrami-cotomy and high resolution electron microscopy. Clays Clay Miner 23 125-129 Lee SY, Jackson ML, Brown JL (1975b) Micaceous vermicuUte, glauconite and mixed-layered kaolinite-montmorillonite by ultramicotomy and high resolution electron microscopy Proc Soil Sci Soc Amer 39 793-800... 

Figure B.2 Symmetric large-angle (113)(TlO] tilt boundary in A1 viewed along the [110] tilt axis by high-resolution electron microscopy. The tilt angle is 50.48°. The inset shows a simulated image [4], Reprinted, by permission, from K.L. Merkle, L.J. Thompson, and F. Phillipp, Thermally activated step motion observed by high-resolution electron microscopy at a (113) symmetric tilt grain-boundary in aluminum," Philosophical Magazine Letters, vol. 82. pp. 589-597. Copyright (c) 2002 by Taylor and Francis Ltd., http //www.tandf.co.uk/journals.

K. L. Merkle, L. J. Thompson, and F. Phillipp. Thermally activated step motion observed by high-resolution electron microscopy at a (113) symmetric tilt grain-boundary in aluminium. Phil. Mag. Lett., 82 589-597, 2002. 

In 1995, Crespi et al. used high-resolution electron microscopy to investigate the structure of slightly silver-deficient Ag2 vV40, [58], During the discharge reaction, silver particles were observed on the outside of the needle-shaped SVO particles, which confirmed that the first step in the lithiation of this material was reduction of silver. The stacking of the vanadium oxide layers was also found to become random in this process. 

Although high resolution electron microscopy studies have identified mazzite overgrowths on ECR-1 (5.), similar mordenite overgrowths have not yet been observed. In no syntheses have mazzite and mordenite been observed to cocrystallize. 

In the PBS rods the phycobiliprotein hexamers can be identified by high-resolution electron microscopy as discs, subdivided into two halfs (a/3-trimers) of 30 A thickness [80,143]. Deeper insight into the molecular structure of the trimers and hexamers was achieved by X-ray crystallographic analyses of biliproteins. In the last century, strikingly coloured phycocyanin and phycoerythrin crystals had already been observed by Molish [144]. Recently, several C-phycocyanins [145-147], B-phycoerythrin [147,148] and phycoerythrocyanin [149] have been crystallized... 

The structure of the striated muscle and in particular the distribution of actin and myosin within the myofibril is well established today. This concerns not only the topography but the functional state as well and is the result of a whole series of admirable observations involving more recently high-resolution electron microscopy on ultrathin sections (see review by Huxley and Hanson, 1960). The striated muscle is composed of fibers consisting of giant multinucleated cells. These fibers contain the myofibrils in a longitudinal arrangement which is characterized by a transversal... 

Hardacre el al. (7 75, 174) investigated the properties, structure, and composition of cerium oxide films prepared by cerium deposition on Pt(lll), finding that the activity for CO oxidation is enhanced on Pt(lll) that is partially covered by ceria. It was suggested that new sites at the Pt-oxide interface become available for reaction. A remarkable observation is the high activity for CO oxidation when the Pt(lll) sample is fully encapsulated by ceria (Pt was undetectable by XPS and AES). It was proposed that an ultrathin, disordered ceria film becomes the active catalyst. It was also demonstrated by XPS and AES that Pt dramatically increases the reducibility of cerium oxide that is in intimate contact with Pt. This result suggests that intimate contact between the noble metal and oxide phases is indeed crucial to facile oxygen release from ceria. High-resolution electron microscopy demonstrated the presence of direct contact between ceria and noble metal for supported Pt-Rh catalysts (775). Hardacre et al. (173,174) related the catalytic activity of the ceria phase to partially reduced cerium oxide. 

O Reilly W (1984) Rock and Mineral Magnetism. Blackie, Glasgow, London O Reilly W, Baneqee SK (1965) Cation distribution in titanomagnetites. Phys Lett 17 237-238 Otsuka N, Sato H (1986) Observation of the Verwey transition in Fe304 by high-resolution electron microscopy. J Solid State Chem 61 212-222... 

The effect of grain size is not always observed experimentally. Table V reports some data about the alkylation of toluene with methanol as a function of the grain size of ZSM-5 and ZSM-11 zeolite samples. It clearly appears that, as expected, a higher selectivity to para-xylene is obtained when the grain size of the ZSM-5 zeolite increases. This does not seem to hold true for ZSM-11, samples prepared in our laboratory. However, a detailed high resolution electron microscopy (HREM) study of the morphology of the grains has shown (63) that ... 

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