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Sample records for high-resolution transmission electron

  1. Structure Identification in High-Resolution Transmission Electron Microscopic Images

    DEFF Research Database (Denmark)

    Vestergaard, Jacob Schack; Kling, Jens; Dahl, Anders Bjorholm

    2014-01-01

    A connection between microscopic structure and macroscopic properties is expected for almost all material systems. High-resolution transmission electron microscopy is a technique offering insight into the atomic structure, but the analysis of large image series can be time consuming. The present ...

  2. High-resolution imaging in the scanning transmission electron microscope

    International Nuclear Information System (INIS)

    Pennycook, S.J.; Jesson, D.E.

    1992-03-01

    The high-resolution imaging of crystalline materials in the scanning transmission electron microscopy (STEM) is reviewed with particular emphasis on the conditions under which an incoherent image can be obtained. It is shown that a high-angle annular detector can be used to break the coherence of the imaging process, in the transverse plane through the geometry of the detector, or in three dimensions if multiphonon diffuse scattering is detected. In the latter case, each atom can be treated as a highly independent source of high-angle scattering. The most effective fast electron states are therefore tightly bound s-type Bloch states. Furthermore, they add constructively for each incident angle in the coherent STEM probe, so that s states are responsible for practically the entire image contrast. Dynamical effects are largely removed, and almost perfect incoherent imaging is achieved. s states are relatively insensitive to neighboring strings, so that incoherent imaging is maintained for superlattice and interfaces, and supercell calculations are unnecessary. With an optimum probe profile, the incoherent image represents a direct image of the crystal projection, with compositional sensitivity built in through the strong dependence of the scattering cross sections on atomic number Z

  3. Observations of silicon carbide by high resolution transmission electron microscopy

    International Nuclear Information System (INIS)

    Smith, D.J.; Jepps, N.W.; Page, T.F.

    1978-01-01

    High resolution transmission electron microscopy techniques, principally involving direct lattice imaging, have been used as part of a study of the crystallography and phase transformation mechanics of silicon carbide polytypes. In particular, the 3C (cubic) and 6H (hexagonal) polytypes have been examined together with partially transformed structural mixtures. Although direct observation of two-dimensional atomic structures was not possible at an operating voltage of 100 kV, considerable microstructural information has been obtained by careful choice of the experimental conditions. In particular, tilted beam observations of the 0.25 nm lattice fringes have been made in the 3C polytype for two different brace 111 brace plane arrays in order to study the dimensions and coherency of finely-twinned regions together with brace 0006 brace and brace 1 0 bar1 2 brace lattice images in the 6H polytype which allow the detailed stacking operations to be resolved. Lower resolution lattice images formed with axial illumination have also been used to study the nature of the 3C → 6H transformation and results are presented showing that the transformation interface may originate with fine twinning of the 3C structure followed by growth of the resultant 6H regions. Observations have been made of the detailed stepped structure of this interface together with the stacking fault distribution in the resultant 6H material. (author)

  4. Computer simulation of high resolution transmission electron micrographs: theory and analysis

    International Nuclear Information System (INIS)

    Kilaas, R.

    1985-03-01

    Computer simulation of electron micrographs is an invaluable aid in their proper interpretation and in defining optimum conditions for obtaining images experimentally. Since modern instruments are capable of atomic resolution, simulation techniques employing high precision are required. This thesis makes contributions to four specific areas of this field. First, the validity of a new method for simulating high resolution electron microscope images has been critically examined. Second, three different methods for computing scattering amplitudes in High Resolution Transmission Electron Microscopy (HRTEM) have been investigated as to their ability to include upper Laue layer (ULL) interaction. Third, a new method for computing scattering amplitudes in high resolution transmission electron microscopy has been examined. Fourth, the effect of a surface layer of amorphous silicon dioxide on images of crystalline silicon has been investigated for a range of crystal thicknesses varying from zero to 2 1/2 times that of the surface layer

  5. Gas-phase synthesis of magnesium nanoparticles : A high-resolution transmission electron microscopy study

    NARCIS (Netherlands)

    Kooi, B.J.; Palasantzas, G.; de Hosson, J.T.M.

    2006-01-01

    Magnesium nanoparticles with size above 10 nm, prepared by gas-phase syntheses, were investigated by high-resolution transmission electron microscopy. The dominant particle shape is a hexagonal prism terminated by Mg(0002) and Mg{1010} facets. Oxidation of Mg yields a MgO shell (similar to 3 nm

  6. Gas-phase synthesis of magnesium nanoparticles: A high-resolution transmission electron microscopy study

    International Nuclear Information System (INIS)

    Kooi, B. J.; Palasantzas, G.; De Hosson, J. Th. M.

    2006-01-01

    Magnesium nanoparticles with size above 10 nm, prepared by gas-phase syntheses, were investigated by high-resolution transmission electron microscopy. The dominant particle shape is a hexagonal prism terminated by Mg(0002) and Mg(1010) facets. Oxidation of Mg yields a MgO shell (∼3 nm thick), which has an orientation relation with the Mg. Inhomogeneous facet oxidation influences their growth kinetics resulting in a relatively broad size and shape distribution. Faceted voids between Mg and MgO shells indicate a fast outward diffusion of Mg and vacancy rearrangement into voids. The faceting of polar (220) planes is assisted by electron irradiation

  7. High-resolution transmission electron microscopy and energetics of flattened carbon nonoshells

    International Nuclear Information System (INIS)

    Bourgeois, L.N.; Bursill, L.A.

    1998-01-01

    When examined under a high-resolution transmission electron microscope, carbon soot produced alongside buckytubes in an arc-discharge is found to contain a small percentage of flattened carbon shells. These objects are shown to be small graphite flakes which eliminated their dangling bonds by terminating their edges with highly curved junctions. Ideal models for these structures are presented, and their energy estimated. The calculations show that the establishment of highly curved junctions is energetically favourable for a graphite flake in an inert atmosphere. Flattened shells also appear more stable than their 'inflated' counterparts (fullerene 'onions' and buckytubes) when the shell dimensions obey specific criteria.(authors)

  8. A graphene oxide-carbon nanotube grid for high-resolution transmission electron microscopy of nanomaterials

    International Nuclear Information System (INIS)

    Zhang Lina; Zhang Haoxu; Zhou Ruifeng; Chen Zhuo; Li Qunqing; Fan Shoushan; Jiang Kaili; Ge Guanglu; Liu Renxiao

    2011-01-01

    A novel grid for use in transmission electron microscopy is developed. The supporting film of the grid is composed of thin graphene oxide films overlying a super-aligned carbon nanotube network. The composite film combines the advantages of graphene oxide and carbon nanotube networks and has the following properties: it is ultra-thin, it has a large flat and smooth effective supporting area with a homogeneous amorphous appearance, high stability, and good conductivity. The graphene oxide-carbon nanotube grid has a distinct advantage when characterizing the fine structure of a mass of nanomaterials over conventional amorphous carbon grids. Clear high-resolution transmission electron microscopy images of various nanomaterials are obtained easily using the new grids.

  9. Practical Approaches to Mitigation of Specimen Charging in High-Resolution Transmission Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Young-Min Kim

    2010-09-01

    Full Text Available Specimen charging that is associated with the electron bombardment on the sample is a practical hindrance to high-resolution transmission electron microscopy (HRTEM analysis because it causes a severe loss of resolution in either diffraction or image data. Conductive thin film deposition on an insulating specimen has been proposed as an effective approach to the mitigation of the specimen charging; however, this method is generally not useful in HRTEM imaging of materials because the deposited film induces another artifact in the HRTEM image contrast. In this study, we propose practical methods to mitigate the specimen charging that takes place during the HRTEM of materials. For bulk-type specimens prepared by either an ion-thinning or focused-ion beam (FIB process, a plasma cleaning treatment is significantly effective in eliminating the charging phenomenon. In the case of low-dimensional nanomaterials such as nanowires and nanoparticles, the plasma cleaning is not feasible; however, the charging effect can be effectively eliminated by adjusting the electron illumination condition. The proposed methods facilitate a decrease in the buildup of specimen charging, thereby enhancing the quality of high-resolution images significantly.

  10. On the optical stability of high-resolution transmission electron microscopes

    International Nuclear Information System (INIS)

    Barthel, J.; Thust, A.

    2013-01-01

    In the recent two decades the technique of high-resolution transmission electron microscopy experienced an unprecedented progress through the introduction of hardware aberration correctors and by the improvement of the achievable resolution to the sub-Ångström level. The important aspect that aberration correction at a given resolution requires also a well defined amount of optical stability has received little attention so far. Therefore we investigate the qualification of a variety of high-resolution electron microscopes to maintain an aberration corrected optical state in terms of an optical lifetime. We develop a comprehensive statistical framework for the estimation of the optical lifetime and find remarkably low values between tens of seconds and a couple of minutes. Probability curves are introduced, which inform the operator about the chance to work still in the fully aberration corrected state. - Highlights: • We investigate the temporal stability of optical aberrations in HRTEM. • We develop a statistical framework for the estimation of optical lifetimes. • We introduce plots showing the success probability for aberration-free work. • Optical lifetimes in sub-Ångström electron microscopy are surprisingly low. • The success of aberration correction depends strongly on the optical stability

  11. High resolution Transmission Electron Microscopy characterization of a milled oxide dispersion strengthened steel powder

    Energy Technology Data Exchange (ETDEWEB)

    Loyer-Prost, M., E-mail: marie.loyer-prost@cea.fr [DEN-Service de Recherches de Métallurgie Physique, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette (France); Merot, J.-S. [Laboratoire d’Etudes des Microstructures – UMR 104, CNRS/ONERA, BP72-29, Avenue de la Division Leclerc, 92 322, Châtillon (France); Ribis, J. [DEN-Service de Recherches de Métallurgie Appliquée, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette (France); Le Bouar, Y. [Laboratoire d’Etudes des Microstructures – UMR 104, CNRS/ONERA, BP72-29, Avenue de la Division Leclerc, 92 322, Châtillon (France); Chaffron, L. [DEN-Service de Recherches de Métallurgie Appliquée, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette (France); Legendre, F. [DEN-Service de la Corrosion et du Comportement des Matériaux dans leur Environnement, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette (France)

    2016-10-15

    Oxide Dispersion Strengthened (ODS) steels are promising materials for generation IV fuel claddings as their dense nano-oxide dispersion provides good creep and irradiation resistance. Even if they have been studied for years, the formation mechanism of these nano-oxides is still unclear. Here we report for the first time a High Resolution Transmission Electron Microscopy and Energy Filtered Transmission Electron Microscopy characterization of an ODS milled powder. It provides clear evidence of the presence of small crystalline nanoclusters (NCs) enriched in titanium directly after milling. Small NCs (<5 nm) have a crystalline structure and seem partly coherent with the matrix. They have an interplanar spacing close to the (011) {sub bcc} iron structure. They coexist with larger crystalline spherical precipitates of 15–20 nm in size. Their crystalline structure may be metastable as they are not consistent with any Y-Ti-O or Ti-O structure. Such detailed observations in the as-milled grain powder confirm a mechanism of Y, Ti, O dissolution in the ferritic matrix followed by a NC precipitation during the mechanical alloying process of ODS materials. - Highlights: • We observed an ODS ball-milled powder by high resolution transmission microscopy. • The ODS ball-milled powder exhibits a lamellar microstructure. • Small crystalline nanoclusters were detected in the milled ODS powder. • The nanoclusters in the ODS milled powder are enriched in titanium. • Larger NCs of 15–20 nm in size are, at least, partly coherent with the matrix.

  12. Nano features of Al/Au ultrasonic bond interface observed by high resolution transmission electron microscopy

    International Nuclear Information System (INIS)

    Ji Hongjun; Li Mingyu; Kim, Jong-Myung; Kim, Dae-Won; Wang Chunqing

    2008-01-01

    Nano-scale interfacial details of ultrasonic AlSi1 wire wedge bonding to a Au/Ni/Cu pad were investigated using high resolution transmission electron microscopy (HRTEM). The intermetallic phase Au 8 Al 3 formed locally due to diffusion and reaction activated by ultrasound at the Al/Au bond interface. Multilayer sub-interfaces roughly parallel to the wire/pad interface were observed among this phase, and interdiffusional features near the Au pad resembled interference patterns, alternately dark and bright bars. Solid-state diffusion theory cannot be used to explain why such a thick compound formed within milliseconds at room temperature. The major formation of metallurgical bonds was attributed to ultrasonic cyclic vibration

  13. High Resolution Transmission Electron Microscope Observation of Zero-Strain Deformation Twinning Mechanisms in Ag

    Science.gov (United States)

    Liu, L.; Wang, J.; Gong, S. K.; Mao, S. X.

    2011-04-01

    We have observed a new deformation-twinning mechanism using the high resolution transmission electron microscope in polycrystalline Ag films, zero-strain twinning via nucleation, and the migration of a Σ3{112} incoherent twin boundary (ITB). This twinning mechanism produces a near zero macroscopic strain because the net Burgers vectors either equal zero or are equivalent to a Shockley partial dislocation. This observation provides new insight into the understanding of deformation twinning and confirms a previous hypothesis: detwinning could be accomplished via the nucleation and migration of Σ3{112} ITBs. The zero-strain twinning mechanism may be unique to low staking fault energy metals with implications for their deformation behavior.

  14. High resolution transmission electron microscopic study of nanoporous carbon consisting of curved single graphite sheets

    International Nuclear Information System (INIS)

    Bourgeois, L.N.; Bursill, L.A.

    1997-01-01

    A high resolution transmission electron microscopic study of a nanoporous carbon rich in curved graphite monolayers is presented. Observations of very thin regions. including the effect of tilting the specimen with respect to the electron beam, are reported. The initiation of single sheet material on an oriented graphite substrate is also observed. When combined with image simulations and independent measurements of the density (1.37g cm -3 ) and sp 3 /sp 2 +sp 2 bonding fraction (0.16), these observations suggest that this material is a two phase mixture containing a relatively low density aggregation of essentially capped single shells like squat nanotubes and polyhedra, plus a relatively dense 'amorphous' carbon structure which may be described using a random-Schwarzite model. Some negatively-curved sheets were also identified in the low density phase. Finally, some discussion is offered regarding the growth mechanisms responsible for this nanoporous carbon and its relationship with the structures of amorphous carbons across a broad range of densities, porosities and sp 3 /sp 2 +sp 3 bonding fractions

  15. An improved image alignment procedure for high-resolution transmission electron microscopy.

    Science.gov (United States)

    Lin, Fang; Liu, Yan; Zhong, Xiaoyan; Chen, Jianghua

    2010-06-01

    Image alignment is essential for image processing methods such as through-focus exit-wavefunction reconstruction and image averaging in high-resolution transmission electron microscopy. Relative image displacements exist in any experimentally recorded image series due to the specimen drifts and image shifts, hence image alignment for correcting the image displacements has to be done prior to any further image processing. The image displacement between two successive images is determined by the correlation function of the two relatively shifted images. Here it is shown that more accurate image alignment can be achieved by using an appropriate aperture to filter the high-frequency components of the images being aligned, especially for a crystalline specimen with little non-periodic information. For the image series of crystalline specimens with little amorphous, the radius of the filter aperture should be as small as possible, so long as it covers the innermost lattice reflections. Testing with an experimental through-focus series of Si[110] images, the accuracies of image alignment with different correlation functions are compared with respect to the error functions in through-focus exit-wavefunction reconstruction based on the maximum-likelihood method. Testing with image averaging over noisy experimental images from graphene and carbon-nanotube samples, clear and sharp crystal lattice fringes are recovered after applying optimal image alignment. Copyright 2010 Elsevier Ltd. All rights reserved.

  16. Linear versus non-linear structural information limit in high-resolution transmission electron microscopy

    International Nuclear Information System (INIS)

    Van Aert, S.; Chen, J.H.; Van Dyck, D.

    2010-01-01

    A widely used performance criterion in high-resolution transmission electron microscopy (HRTEM) is the information limit. It corresponds to the inverse of the maximum spatial object frequency that is linearly transmitted with sufficient intensity from the exit plane of the object to the image plane and is limited due to partial temporal coherence. In practice, the information limit is often measured from a diffractogram or from Young's fringes assuming a weak phase object scattering beyond the inverse of the information limit. However, for an aberration corrected electron microscope, with an information limit in the sub-angstrom range, weak phase objects are no longer applicable since they do not scatter sufficiently in this range. Therefore, one relies on more strongly scattering objects such as crystals of heavy atoms observed along a low index zone axis. In that case, dynamical scattering becomes important such that the non-linear and linear interaction may be equally important. The non-linear interaction may then set the experimental cut-off frequency observed in a diffractogram. The goal of this paper is to quantify both the linear and the non-linear information transfer in terms of closed form analytical expressions. Whereas the cut-off frequency set by the linear transfer can be directly related with the attainable resolution, information from the non-linear transfer can only be extracted using quantitative, model-based methods. In contrast to the historic definition of the information limit depending on microscope parameters only, the expressions derived in this paper explicitly incorporate their dependence on the structure parameters as well. In order to emphasize this dependence and to distinguish from the usual information limit, the expressions derived for the inverse cut-off frequencies will be referred to as the linear and non-linear structural information limit. The present findings confirm the well-known result that partial temporal coherence has

  17. High resolution transmission electron microscopy studies of {sigma} phase in Ni-based single crystal superalloys

    Energy Technology Data Exchange (ETDEWEB)

    Sun Fei [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Zhang Jianxin, E-mail: jianxin@sdu.edu.cn [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Liu Pan [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China); Feng Qiang [National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Han Xiaodong; Mao Shengcheng [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China)

    2012-09-25

    Graphical abstract: (a) TEM micrograph of {sigma} phase; (b) HRTEM image of {sigma}/{gamma} interface corresponding to the area of the white frame in (a); (c) an enlarged image of area from the white frame in (b). The combination of {sigma}/{gamma} interface appears very well, and a two-atomic-layer step is shown on the {sigma}/{gamma} interface. In addition, {sigma} phase has the orientation relationship of [0 0 1]{sub {gamma}}//[1 1 2{sup Macron }]{sub {sigma}}, (2{sup Macron} 2 0){sub {gamma}}//(1{sup Macron} 1 0){sub {sigma}}, (2{sup Macron }2{sup Macron} 0){sub {gamma}}//(1 1 1){sub {sigma}}; [0 1 1]{sub {gamma}}//[1 1 0]{sub {sigma}}, (1 1{sup Macron} 1){sub {gamma}}//(0 0 1{sup Macron }){sub {sigma}} with the {gamma} phase. Highlights: Black-Right-Pointing-Pointer Elemental characteristic of {sigma} phase is studied by HAADF techniques and EDS analysis. Black-Right-Pointing-Pointer Interfacial characteristics of {sigma}/{gamma} interface are revealed by HRTEM. Black-Right-Pointing-Pointer An atomic structural {sigma}/{gamma} interface with a two-atomic-layer step has been proposed. - Abstract: By means of high resolution transmission electron microscopy (HRTEM) and high-angle annular dark-field image technique (HAADF), morphological of plate-shaped {sigma} phase and interfacial characteristics between plate-shaped {sigma} phase and {gamma} phase in Ni-based single crystal superalloys have been studied. On the basis of HRTEM observations, an atomic structural interface between {sigma} phase and {gamma} phase with a step has been proposed. {sigma} Phase has the relationship of [0 0 1]{sub {gamma}}//[1 1 2{sup Macron }]{sub {sigma}}, (2{sup Macron} 2 0){sub {gamma}}//(1{sup Macron} 1 0){sub {sigma},} (2{sup Macron }2{sup Macron} 0){sub {gamma}}//(1 1 1){sub {sigma}}; [0 1 1]{sub {gamma}}//[1 1 0]{sub {sigma}}, (1 1{sup Macron} 1){sub {gamma}}//(0 0 1{sup Macron }){sub {sigma}} with the {gamma} phase. The compositional characteristics of the {sigma} phase which

  18. High resolution transmission electron microscopy and microdiffraction for radiation damage analysis

    International Nuclear Information System (INIS)

    Sinclair, R.

    1982-01-01

    High resolution TEM techniques have developed to quite a sophisticated level over the past few years. In addition TEM instruments with a scanning capability have become available commercially which permit in particular the formation of a small electron probe at the specimen. Thus direct resolution and microdiffraction investigations of thin specimens are now possible, neither of which have been employed to any great extent in the analysis of radiation damage. Some recent advances which are thought to be relevant to this specific area of research are highlighted

  19. High-resolution transmission electron microscopy of grain-refining particles in amorphous aluminum alloys

    International Nuclear Information System (INIS)

    Schumacher, P.; Greer, A.L.

    1996-01-01

    The nucleation mechanism of Al-Ti-B grain refiners is studied in an Al-based amorphous alloy. The ability to limit growth of α-Al in the amorphous alloy permits the microscopical observation of nucleation events on boride particles. Earlier studies of this kind are extended by using high-resolution electron microscopy. This shows that the efficient nucleation α-Al depends on the TiB 2 particles being coated with a thin layer of Al 3 Ti, which can form only when there is some excess titanium in the melt. The aluminide layer, stabilized by adsorption effects, can be as little as a few monolayers thick, and is coherent with the boride. The nature of this layer, and its importance for the nucleation mechanism are discussed. The fading of the grain refinement action is also considered

  20. Method and apparatus for a high-resolution three dimensional confocal scanning transmission electron microscope

    Science.gov (United States)

    de Jonge, Niels [Oak Ridge, TN

    2010-08-17

    A confocal scanning transmission electron microscope which includes an electron illumination device providing an incident electron beam propagating in a direction defining a propagation axis, and a precision specimen scanning stage positioned along the propagation axis and movable in at least one direction transverse to the propagation axis. The precision specimen scanning stage is configured for positioning a specimen relative to the incident electron beam. A projector lens receives a transmitted electron beam transmitted through at least part of the specimen and focuses this transmitted beam onto an image plane, where the transmitted beam results from the specimen being illuminated by the incident electron beam. A detection system is placed approximately in the image plane.

  1. Understanding the structure of nanocatalysts with high resolution scanning/transmission electron microscopy

    International Nuclear Information System (INIS)

    Francis, L D; Rivas, J; José-Yacamán, M

    2014-01-01

    Nanomaterials including nanoparticles, nanowires and nanotubes play an important role in heterogeneous catalysis. Thanks to the rapid improvement of the electron microscopic techniques and with the advent of aberration corrected electron microscopy as well as theoretical methodologies, the potential effects induced by nanocatalysts are better understood than before by unravelling their atomic structure. A brief introduction to advanced electron microscopic techniques namely aberration corrected scanning transmission electron microscopy (Cs-STEM) is presented and subsequently two examples of nanocatalysts are considered in the present review. The first example will focus on the study of bimetallic/core-shell nanoalloys. In heterogeneous catalysis, catalysts containing two or more metals might show significantly different catalytic properties compared to the parent metals and thus are widely utilized in several catalytic reactions. Atom-by-atom insights of the nanoalloy based catalysts ex: Au-Pd will be described in the present review using a combination of advanced electron microscopic and spectroscopic techniques. A related example on the understanding of bimetallic clusters by HAADF-STEM will also be presented in addition to nanoparticles. In the second case understanding the structure of transition metal chalcogenide based nanocatalysts by HRTEM and aberration corrected STEM, for the case of MoS 2 will be discussed. MoS 2 -based catalysts serve as model catalysts and are employed in the hydrodesulphurisations (HDS) reactions in the removal of sulphur from gasoline and related petrochemical products. They have been studied in various forms including nanowires, nanotubes and nanoplates. Their structure, atomic insights and as a consequence elucidation of their corresponding catalytic activity are thus important

  2. Transformations of gold nanoparticles investigated using variable temperature high-resolution transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Young, N.P. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Huis, M.A. van; Zandbergen, H.W. [Kavli Institute of Nanoscience, Delft University of Technolgy, Lorentzweg 1, NL-2628CJ, Delft, The Netherlands. (Netherlands); Xu, H. [Department of Geology and Geophysics, and Materials Science Program, University of Wisconsin-Madison, Madison, WI (United States); Kirkland, A.I., E-mail: angus.kirkland@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom)

    2010-04-15

    Recently designed advanced in-situ specimen holders for transmission electron microscopy (TEM) have been used in studies of gold nanoparticles. We report results of variable temperature TEM experiments in which structural transformations have been correlated with specimen temperature, allowing general trends to be identified. Transformation to a decahedral morphology for particles in the size range 5-12 nm was observed for the majority of particles regardless of their initial structure. Following in-situ annealing, decahedra were found to be stable at room temperature, confirming this as the equilibrium morphology, in agreement with recently calculated phase diagrams. Other transitions at low temperature in addition to surface roughening have also been observed and correlated with the same nanoscale phase diagram. Investigations of gold particles at high temperature have revealed evidence for co-existing solid and liquid phases. Overall, these results are important in a more precise understanding of the structure and action of catalytic gold nanoparticles and in the experimental verification of theoretical calculations.

  3. In situ electrical probing and bias-mediated manipulation of dielectric nanotubes in a high-resolution transmission electron microscope

    International Nuclear Information System (INIS)

    Golberg, D.; Mitome, M.; Kurashima, K.; Zhi, C.Y.; Tang, C.C.; Bando, Y.; Lourie, O.

    2006-01-01

    Boron nitride nanotubes filled with magnesium oxides [MgO, MgO 2 ] and/or hydroxide [Mg(OH) 2 ] are electrically probed and delicately manipulated inside a 300 kV JEOL-3000F high-resolution transmission analytical electron microscope equipped with a side-entry 'Nanofactory Instruments' piezoholder. At a low bias the nanotubes demonstrate truly insulating behavior. At a high bias of ±30 V they show reversible breakdown current of several dozens of nA. Under 300 kV electron beam irradiation the nanotubes are positively charged that allows us to perform on-demand manipulation with them through tuning of polarity and/or value of a bias voltage on a gold counterelectrode from -140 to +140 V, owing to the prominent electrostatic nanotube-electrode interactions

  4. High-resolution visualization of Pseudomonas aeruginosa PAO1 biofilms by freeze-substitution transmission electron microscopy.

    Science.gov (United States)

    Hunter, Ryan C; Beveridge, Terry J

    2005-11-01

    High-pressure freeze-substitution and transmission electron microscopy have been used for high-resolution imaging of the natural structure of a gram-negative biofilm. Unlike more conventional embedding techniques, this method confirms many of the observations seen by confocal microscopy but with finer structural detail. It further reveals that there is a structural complexity to biofilms at both the cellular and extracellular matrix levels that has not been seen before. Different domains of healthy and lysed cells exist randomly dispersed within a single biofilm as well as different structural organizations of exopolymers. Particulate matter is suspended within this network of fibers and appears to be an integral part of the exopolymeric substance (EPS). O-side chains extending from the outer membrane are integrated into EPS polymers so as to form a continuum. Together, the results support the concept of physical microenvironments within biofilms and show a complexity that was hitherto unknown.

  5. Quantitative High Resolution Transmission Electron Microscopy (HRTEM): a novel approach towards application oriented basic research

    International Nuclear Information System (INIS)

    Kisielowski, Christian; Weber, Eicke R.; Liliental-Weber, Zuzanna

    1996-01-01

    This paper reviews recent developments of microscopic methods that base on a quantitative analysis of electron micrographs to access subsurface systems at the atomic scale. It focuses on non-equilibrium diffusion processes that are observed in nano structured MBE grown materials if a low growth temperature was used and on local deviations from a stoichiometric composition of materials. As examples we investigate Ga As/Al As and Si/Ge Si heterostructures and Ga N single crystals. The purpose of the research is twofold. On the one hand it helps understanding physical processes at the atomic scale. On the other hand we can use the results to link basic physical knowledge with the performance of semiconductor devices made from nano structured materials. (author). 28 refs., 15 figs

  6. In situ high-resolution transmission electron microscopy synthesis observation of nanostructured carbon coated LiFePO 4

    Science.gov (United States)

    Trudeau, M. L.; Laul, D.; Veillette, R.; Serventi, A. M.; Mauger, A.; Julien, C. M.; Zaghib, K.

    In situ high-resolution transmission electron microscopy (HRTEM) studies of the structural transformations that occur during the synthesis of carbon-coated LiFePO 4 (C-LiFePO 4) and heat treatment to elevated temperatures were conducted in two different electron microscopes. Both microscopes have sample holders that are capable of heating up to 1500 °C, with one working under high vacuum and the other capable of operating with the sample surrounded by a low gaseous environment. The C-LiFePO 4 samples were prepared using three different compositions of precursor materials with Fe(0), Fe(II) or Fe(III), a Li-containing salt and a polyethylene- block-poly(ethylene glycol)-50% ethylene oxide or lactose. The in situ TEM studies suggest that low-cost Fe(0) and a low-cost carbon-containing compound such as lactose are very attractive precursors for mass production of C-LiFePO 4, and that 700 °C is the optimum synthesis temperature. At temperatures higher than 800 °C, LiFePO 4 has a tendency to decompose. The same in situ measurements have been made on particles without carbon coat. The results show that the homogeneous deposit of the carbon deposit at 700 °C is the result of the annealing that cures the disorder of the surface layer of bare LiFePO 4. Electrochemical tests supported the conclusion that the C-LiFePO 4 derived from Fe(0) is the most attractive for mass production.

  7. Investigation of the martensitic phase transformations in CoFe single crystals using high-resolution transmission electron microscopy

    International Nuclear Information System (INIS)

    Waitz, T.

    1999-06-01

    In CoFe crystals containing 0.85, 1.5, 5.75 and 6.0at.% Fe the thermally induced martensitic phase transformations between the close packed lattices face centered cubic (fcc), double hexagonal close packed (dhcp) and hexagonal close packed (hcp) were studied. Transmission electron microscopy methods were applied including in-situ experiments; both high-resolution transmission electron microscopy (HRTEM) images and lattice fringe images were used to analyze the transformations at an atomic scale. Based on the results of both the transformations in the bulk and the in-situ transformations it is concluded that the phase transitions occur by the formation of lamellae on the close packed habit planes. The lamellae have a minimum thickness of 10 to 15 close packed planes; therefore transformation models that are based on random overlap of stacking faults can be excluded. The glissile transformation fronts of the lamellae contain transformation dislocations (partials) that are correlated on an atomic scale. In the HRTEM images partials that are only about 0.2 nm apart were resolved and analyzed in detail by circuits that are similar to Burgers circuits. Two attracting partials on adjacent close packed planes are the structural units of the transformation fronts; they are dipoles and paired partials (with a total Burgers vector of a single partial) in the case of the transformations hcp dhcp and fcc dhcp, respectively. Different arrangements of the partials at the transformation fronts lead to two different modes A and B of the phase transition. These two modes seem to be competitive processes that can be favored by different parameters of the material (as chemical composition and microstructure). Partials of mode A transformations have the same Burgers vectors; therefore the partials repel each other causing long range internal stresses and large transformation shear strains that can lead to a surface relief. Whereas, partials of mode B transformations have different

  8. High resolution transmission electron microscopy study on the development of nanostructured precipitates in Al-Cu obtained by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Villalba, L.S., E-mail: luzgomez@geo.ucm.es [Materials Science and Engineering Department, Universidad Carlos III de Madrid, Leganes, Madrid (Spain); Instituto de Geociencias-(CSIC-UCM), Madrid (Spain); Delgado, M.L.; Ruiz-Navas, E.M. [Materials Science and Engineering Department, Universidad Carlos III de Madrid, Leganes, Madrid (Spain)

    2012-01-16

    Highlights: Black-Right-Pointing-Pointer Development of defect structures and nanoprecipitates after 10 h of mechanical alloying in Al-Cu system. Black-Right-Pointing-Pointer Defects act as nucleation sites of the {epsilon}Al{sub 2}Cu{sub 3} phase. Black-Right-Pointing-Pointer Incoherent and semicoherent precipitates are identified by TEM-HRTEM. Black-Right-Pointing-Pointer Moire patterns are associated to the {epsilon}Al{sub 2}Cu{sub 3} phase. - Abstract: Aluminum alloy 2014 is used to obtain nanostructured powders via mechanical alloying. The evolution of the diffusion processes is observed by the development of defect structures and nanoprecipitates after 10 h of milling. The characterization includes analytical and high resolution transmission electron microscopy. Dislocations associated with different Al/Cu ratio affect the material. These defects act as nucleation sites where precipitates of the {epsilon}Al{sub 2}Cu{sub 3} hexagonal phase have been identified. Moire fringes show the interference of {l_brace}1 1 1{r_brace}{sub Al} with {l_brace}10{sup -}10{r_brace}{sub {epsilon}Al{sub 2Cu{sub 3}}} glide planes and locally small shifts of 1/3{l_brace}1 1 1{r_brace}{sub Al} and 1/3{l_brace}10{sup -}10{r_brace}{sub {epsilon}Al{sub 2Cu{sub 3}}}. Changes in the Al/Cu ratio lead to the formation of other solid solutions identified in the Cu rich area and could correspond to transition phases.

  9. Neutron irradiation damage of nuclear graphite studied by high-resolution transmission electron microscopy and Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Krishna, R. [Dalton Cumbrian Facility, Dalton Nuclear Institute, The University of Manchester, Westlakes Science & Technology Park, Moor Row, Whitehaven, Cumbria, CA24 3HA (United Kingdom); Jones, A.N., E-mail: Abbie.Jones@manchester.ac.uk [Nuclear Graphite Research Group, School of MACE, The University of Manchester, Manchester, M13 9PL (United Kingdom); McDermott, L.; Marsden, B.J. [Nuclear Graphite Research Group, School of MACE, The University of Manchester, Manchester, M13 9PL (United Kingdom)

    2015-12-15

    Nuclear graphite components are produced from polycrystalline artificial graphite manufacture from a binder and filler coke with approximately 20% porosity. During the operational lifetime, nuclear graphite moderator components are subjected to fast neutron irradiation which contributes to the change of material and physical properties such as thermal expansion co-efficient, young's modulus and dimensional change. These changes are directly driven by irradiation-induced changes to the crystal structure as reflected through the bulk microstructure. It is therefore of critical importance that these irradiation changes and there implication on component property changes are fully understood. This work examines a range of irradiated graphite samples removed from the British Experimental Pile Zero (BEPO) reactor; a low temperature, low fluence, air-cooled Materials Test Reactor which operated in the UK. Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM) have been employed to characterise the effect of increased irradiation fluence on graphite microstructure and understand low temperature irradiation damage processes. HRTEM confirms the structural damage of the crystal lattice caused by irradiation attributed to a high number of defects generation with the accumulation of dislocation interactions at nano-scale range. Irradiation-induced crystal defects, lattice parameters and crystallite size compared to virgin nuclear graphite are characterised using selected area diffraction (SAD) patterns in TEM and Raman Spectroscopy. The consolidated ‘D’peak in the Raman spectra confirms the formation of in-plane point defects and reflected as disordered regions in the lattice. The reduced intensity and broadened peaks of ‘G’ and ‘D’ in the Raman and HRTEM results confirm the appearance of turbulence and disordering of the basal planes whilst maintaining their coherent layered graphite structure. - Highlights: • Irradiated graphite

  10. Neutron irradiation damage of nuclear graphite studied by high-resolution transmission electron microscopy and Raman spectroscopy

    International Nuclear Information System (INIS)

    Krishna, R.; Jones, A.N.; McDermott, L.; Marsden, B.J.

    2015-01-01

    Nuclear graphite components are produced from polycrystalline artificial graphite manufacture from a binder and filler coke with approximately 20% porosity. During the operational lifetime, nuclear graphite moderator components are subjected to fast neutron irradiation which contributes to the change of material and physical properties such as thermal expansion co-efficient, young's modulus and dimensional change. These changes are directly driven by irradiation-induced changes to the crystal structure as reflected through the bulk microstructure. It is therefore of critical importance that these irradiation changes and there implication on component property changes are fully understood. This work examines a range of irradiated graphite samples removed from the British Experimental Pile Zero (BEPO) reactor; a low temperature, low fluence, air-cooled Materials Test Reactor which operated in the UK. Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM) have been employed to characterise the effect of increased irradiation fluence on graphite microstructure and understand low temperature irradiation damage processes. HRTEM confirms the structural damage of the crystal lattice caused by irradiation attributed to a high number of defects generation with the accumulation of dislocation interactions at nano-scale range. Irradiation-induced crystal defects, lattice parameters and crystallite size compared to virgin nuclear graphite are characterised using selected area diffraction (SAD) patterns in TEM and Raman Spectroscopy. The consolidated ‘D’peak in the Raman spectra confirms the formation of in-plane point defects and reflected as disordered regions in the lattice. The reduced intensity and broadened peaks of ‘G’ and ‘D’ in the Raman and HRTEM results confirm the appearance of turbulence and disordering of the basal planes whilst maintaining their coherent layered graphite structure. - Highlights: • Irradiated graphite exhibits

  11. High-resolution electron microscopy

    CERN Document Server

    Spence, John C H

    2013-01-01

    This new fourth edition of the standard text on atomic-resolution transmission electron microscopy (TEM) retains previous material on the fundamentals of electron optics and aberration correction, linear imaging theory (including wave aberrations to fifth order) with partial coherence, and multiple-scattering theory. Also preserved are updated earlier sections on practical methods, with detailed step-by-step accounts of the procedures needed to obtain the highest quality images of atoms and molecules using a modern TEM or STEM electron microscope. Applications sections have been updated - these include the semiconductor industry, superconductor research, solid state chemistry and nanoscience, and metallurgy, mineralogy, condensed matter physics, materials science and material on cryo-electron microscopy for structural biology. New or expanded sections have been added on electron holography, aberration correction, field-emission guns, imaging filters, super-resolution methods, Ptychography, Ronchigrams, tomogr...

  12. Piezoelectric properties of PbTiO(3) thin films characterized with piezoresponse force and high resolution transmission electron microscopy

    NARCIS (Netherlands)

    Morelli, A.; Venkatesan, Sriram; Kooi, B. J.; Palasantzas, G.; De Hosson, J. Th. M.

    2009-01-01

    In this paper we investigate the piezoelectric properties of PbTiO(3) thin films grown by pulsed laser deposition with piezoresponse force microscopy and transmission electron microscopy. The as-grown films exhibit an upward polarization, inhomogeneous distribution of piezoelectric characteristics

  13. Specific, sensitive, high-resolution detection of protein molecules in eukaryotic cells using metal-tagging transmission electron microscopy

    Science.gov (United States)

    Risco, Cristina; Sanmartín-Conesa, Eva; Tzeng, Wen-Pin; Frey, Teryl K.; Seybold, Volker; de Groot, Raoul J.

    2012-01-01

    Summary More than any other methodology, transmission electron microscopy (TEM) has contributed to our understanding of the architecture and organization of cells. With current detection limits approaching atomic resolution, it will ultimately become possible to ultrastructurally image intracellular macromolecular assemblies in situ. Presently, however, methods to unambiguously identify proteins within the crowded environment of the cell’s interior are lagging behind. We describe a novel approach, metal-tagging TEM (METTEM) that allows detection of intracellular proteins in mammalian cells with high specificity, exceptional sensitivity and at molecular scale resolution. In live cells treated with gold salts, proteins bearing a small metal-binding tag will form 1-nm gold nanoclusters, readily detectable in electron micrographs. The applicability and strength of METTEM is demonstrated by a study of Rubella virus replicase and capsid proteins, which revealed virus-induced cell structures not seen before. PMID:22579245

  14. Improved methods for high resolution electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, J.R.

    1987-04-01

    Existing methods of making support films for high resolution transmission electron microscopy are investigated and novel methods are developed. Existing methods of fabricating fenestrated, metal reinforced specimen supports (microgrids) are evaluated for their potential to reduce beam induced movement of monolamellar crystals of C/sub 44/H/sub 90/ paraffin supported on thin carbon films. Improved methods of producing hydrophobic carbon films by vacuum evaporation, and improved methods of depositing well ordered monolamellar paraffin crystals on carbon films are developed. A novel technique for vacuum evaporation of metals is described which is used to reinforce microgrids. A technique is also developed to bond thin carbon films to microgrids with a polymer bonding agent. Unique biochemical methods are described to accomplish site specific covalent modification of membrane proteins. Protocols are given which covalently convert the carboxy terminus of papain cleaved bacteriorhodopsin to a free thiol. 53 refs., 19 figs., 1 tab.

  15. Electron diffraction and high-resolution transmission electron microscopy of the high temperature crystal structures of GexSb2Te3+x (x=1,2,3) phase change material

    NARCIS (Netherlands)

    Kooi, B.J.; de Hosson, J.T.M.

    2002-01-01

    The crystal structures of GeSb2Te4, Ge2Sb2Te5, and Ge3Sb2Te6 were determined using electron diffraction and high-resolution transmission electron microscopy. The structure determined for the former two crystals deviates from the ones proposed in the literature. These crystal structures were

  16. Crystal structure and defects of Zr4Co4Si7( V-phase) investigated by high resolution transmission electron microscope

    International Nuclear Information System (INIS)

    Mao, J.F.; Ye, H.Q.; Ning, X.G.; He, L.L.; Yang, D.Z.

    1997-01-01

    The results of high resolution transmission electron microscope (HRTEM) observation and image simulation show that Zr 4 Co 4 Si 7 possesses the same structure type of Zr 4 Co 4 Ge 7 . Adding of Fe or Ni into the Zr 4 Co 4 Si 7 compound, except that the dimensions changed slightly, does not change the lattice type and coordination in the crystal structure, maintaining the V-phase structure. Also, twins with coherent boundaries and with partially coherent at interfaces are observed. The image conditions of Zr 4 Co 4 Si 7 and the structure differences between Zr 4 Co 4 Si 7 and tetrahedral close-packed phases are also discussed. copyright 1997 Materials Research Society

  17. Opto-mechano-electrical tripling in ZnO nanowires probed by photocurrent spectroscopy in a high-resolution transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, C.; Golberg, D., E-mail: xuzhi@iphy.ac.cn, E-mail: golberg.dmitri@nims.go.jp [International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki 3050044 (Japan); Graduate School of Pure and Applied Sciences, University of Tsukuba, Tennodai 1, Tsukuba, Ibaraki 3058577 (Japan); Xu, Z., E-mail: xuzhi@iphy.ac.cn, E-mail: golberg.dmitri@nims.go.jp [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Kvashnin, D. G. [National University of Science and Technology, MISIS, Leninskiy Prospect 4, Moscow 119049 (Russian Federation); Tang, D.-M.; Xue, Y. M.; Bando, Y. [International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki 3050044 (Japan); Sorokin, P. B. [National University of Science and Technology, MISIS, Leninskiy Prospect 4, Moscow 119049 (Russian Federation); Moscow Institute of Physics and Technology, Institutsky Lane 9, Dolgoprudny 141700 (Russian Federation)

    2015-08-31

    Photocurrent spectroscopy of individual free-standing ZnO nanowires inside a high-resolution transmission electron microscope (TEM) is reported. By using specially designed optical in situ TEM system capable of scanning tunneling microscopy probing paired with light illumination, opto-mechano-electrical tripling phenomenon in ZnO nanowires is demonstrated. Splitting of photocurrent spectra at around 3.3 eV under in situ TEM bending of ZnO nanowires directly corresponds to nanowire deformation and appearance of expanded and compressed nanowire sides. Theoretical simulation of a bent ZnO nanowire has an excellent agreement with the experimental data. The splitting effect could be explained by a change in the valence band structure of ZnO nanowires due to a lattice strain. The strain-induced splitting provides important clues for future flexible piezo-phototronics.

  18. Restoring defect structures in 3C-SiC/Si (001) from spherical aberration-corrected high-resolution transmission electron microscope images by means of deconvolution processing.

    Science.gov (United States)

    Wen, C; Wan, W; Li, F H; Tang, D

    2015-04-01

    The [110] cross-sectional samples of 3C-SiC/Si (001) were observed with a spherical aberration-corrected 300 kV high-resolution transmission electron microscope. Two images taken not close to the Scherzer focus condition and not representing the projected structures intuitively were utilized for performing the deconvolution. The principle and procedure of image deconvolution and atomic sort recognition are summarized. The defect structure restoration together with the recognition of Si and C atoms from the experimental images has been illustrated. The structure maps of an intrinsic stacking fault in the area of SiC, and of Lomer and 60° shuffle dislocations at the interface have been obtained at atomic level. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. High resolution transmission imaging without lenses

    International Nuclear Information System (INIS)

    Rodenburg, J M; Hurst, A C; Maiden, A

    2010-01-01

    The whole history of transmission imaging has been dominated by the lens, whether used in visible-light optics, electron optics or X-ray optics. Lenses can be thought of as a very efficient method of processing a wave front scattered from an object into an image of that object. An alternative approach is to undertake this image-formation process using a computational technique. The crudest scattering experiment is to simply record the intensity of a diffraction pattern. Recent progress in so-called diffractive imaging has shown that it is possible to recover the phase of a scattered wavefield from its diffraction pattern alone, as long as the object (or the illumination on the object) is of finite extent. In this paper we present results from a very efficient phase retrieval method which can image infinitely large fields of view. It may have important applications in improving resolution in electron microscopy, or at least allowing low specification microscopes to achieve resolution comparable to state-of-the-art machines.

  20. Structural characterization and gas reactions of small metal particles by high resolution in-situ TEM (Transmission Electron Microscopy) and TED (Transmission Electron Diffraction)

    Science.gov (United States)

    Heinemann, K.

    1987-01-01

    The detection and size analysis of small metal particles supported on amorphous substrates becomes increasingly difficult when the particle size approaches that of the phase contrast background structures of the support. An approach of digital image analysis, involving Fourier transformation of the original image, filtering, and image reconstruction was studied with respect to the likelihood of unambiguously detecting particles of less than 1 nm diameter on amorphous substrates from a single electron micrograph.

  1. Structural Characterization and Gas Reactions of Small Metal Particles by High Resolution In-situ TEM and TED. [Transmission Electron Microscopy and Transmission Electron Diffraction

    Science.gov (United States)

    Heinemann, K.

    1985-01-01

    A commercial electron microscope with flat-plate upper pole piece configuration of the objective lens and top entry specimen introduction was modified to obtain 5 x 10 to the minus 10th power mbar pressure at the site of the specimen while maintaining the convenience of a specimen airlock system that allows operation in the 10 to the 10th power mbar range within 15 minutes after specimen change. The specimen chamber contains three wire evaporation sources, a specimen heater, and facilities for oxygen or hydrogen plasma treatment to clean as-introduced specimens. Evacuation is achieved by dural differential pumping, with fine entrance and exit apertures for the electron beam. With the microscope operating at .000001 mbar, the first differential pumping stage features a high-speed cryopump operating in a stainless steel chamber that can be mildly baked and reaches 1 x 10 to the minus 8th power mbar. The second stage, containing the evaporation sources and a custom ionization gauge within 10 cm from the specimen, is a rigorously uncompromised all-metal uhv-system that is bakable to above 200 C throughout and is pumped with an 80-liter ion pump. Design operating pressures and image quality (resolution of metal particles smaller than 1 nm in size) was achieved.

  2. Zeolites - a high resolution electron microscopy study

    International Nuclear Information System (INIS)

    Alfredsson, V.

    1994-10-01

    High resolution transmission electron microscopy (HRTEM) has been used to investigate a number of zeolites (EMT, FAU, LTL, MFI and MOR) and a member of the mesoporous M41S family. The electron optical artefact, manifested as a dark spot in the projected centre of the large zeolite channels, caused by insufficient transfer of certain reflections in the objective lens has been explained. The artefact severely hinders observation of materials confined in the zeolite channels and cavities. It is shown how to circumvent the artefact problem and how to image confined materials in spite of disturbance caused by the artefact. Image processing by means of a Wiener filter has been applied for removal of the artefact. The detailed surface structure of FAU has been investigated. Comparison of experimental micrographs with images simulated using different surface models indicates that the surface can be terminated in different ways depending on synthesis methods. The dealuminated form of FAU (USY) is covered by an amorphous region. Platinum incorporated in FAU has a preponderance to aggregate in the (111) twin planes, probably due to a local difference in cage structure with more spacious cages. It is shown that platinum is intra-zeolitic as opposed to being located on the external surface of the zeolite crystal. This could be deduced from tomography of ultra-thin sections among observations. HRTEM studies of the mesoporous MCM-41 show that the pores have a hexagonal shape and also supports the mechanistic model proposed which involves a cooperative formation of a mesophase including the silicate species as well as the surfactant. 66 refs, 24 figs

  3. X-ray diffraction and high resolution transmission electron microscopy characterization of intermetallics formed in Fe/Ti nanometer-scale multilayers during thermal annealing

    International Nuclear Information System (INIS)

    Wu, Z.L.; Peng, T.X.; Cao, B.S.; Lei, M.K.

    2009-01-01

    Intermetallics formation in the Fe/Ti nanometer-scale multilayers magnetron-sputtering deposited on Si(100) substrate during thermal annealing at 623-873 K was investigated by using small and wide angle X-ray diffraction and cross-sectional high-resolution transmission electron microscopy. The Fe/Ti nanometer-scale multilayers were constructed with bilayer thickness of 16.2 nm and the sublayer thickness ratio of 1:1. At the annealing temperature of 623 K, intermetallics FeTi were formed by nucleation at the triple joins of α-Fe(Ti)/α-Ti interface and α-Ti grain boundary with an orientational correlation of FeTi(110)//α-Ti(100) and FeTi[001]//α-Ti[001] to adjacent α-Ti grains. The lateral growth of intermetallics FeTi which is dependent on the diffusion path of Ti led to a coalescence into an intermetallic layer. With an increase in the annealing temperature, intermetallics Fe 2 Ti were formed between the intermetallics FeTi and the excess Fe due to the limitation of Fe and Ti atomic concentrations, resulting in the coexistence of intermetallics FeTi and Fe 2 Ti. It was found that the low energy interface as well as the dominant diffusion path constrained the nucleation and growth of intermetallics during interfacial reaction in the nanometer-scale metallic multilayers.

  4. High-resolution transmission electron microscopy studies of graphite materials prepared by high-temperature treatment of unburned carbon concentrates from combustion fly ashes

    Energy Technology Data Exchange (ETDEWEB)

    Miguel Cabielles; Jean-Nol Rouzaud; Ana B. Garcia [Instituto Nacional del Carbn (INCAR), Oviedo (Spain)

    2009-01-15

    High-resolution transmission electron microscopy (HRTEM) has been used in this work to study the microstructural (structure and microtexture) changes occurring during the high-temperature treatment of the unburned carbon concentrates from coal combustion fly ashes. Emphasis was placed on two aspects: (i) the development of graphitic carbon structures and (ii) the disordered carbon forms remaining in the graphitized samples. In addition, by coupling HRTEM with energy-dispersive spectroscopy, the transformations with the temperature of the inorganic matter (mainly iron- and silicon-based phases) of the unburned carbon concentrates were evidenced. The HRTEM results were compared to the averaged structural order of the materials as evaluated by X-ray diffraction (XRD) and Raman spectroscopy. As indicated by XRD and Raman parameters, more-ordered materials were obtained from the unburned carbon concentrates with higher mineral/inorganic matter, thus inferring the catalytic effect of some of their components. However, the average character of the information provided by these instrumental techniques seems to be inconclusive in discriminating between carbon structures with different degrees of order (stricto sensu graphite, graphitic, turbostratic, etc.) in a given graphitized unburned carbon. Unlike XRD and Raman, HRTEM is a useful tool for imaging directly the profile of the polyaromatic layers (graphene planes), thus allowing the sample heterogeneity to be looked at, specifically the presence of disordered carbon phases. 49 refs., 9 figs., 3 tabs.

  5. High-resolution electron microscopy of advanced materials

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, T.E.; Kung, H.H.; Sickafus, K.E.; Gray, G.T. III; Field, R.D.; Smith, J.F. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.

    1997-11-01

    This final report chronicles a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The High-Resolution Electron Microscopy Facility has doubled in size and tripled in quality since the beginning of the three-year period. The facility now includes a field-emission scanning electron microscope, a 100 kV field-emission scanning transmission electron microscope (FE-STEM), a 300 kV field-emission high-resolution transmission electron microscope (FE-HRTEM), and a 300 kV analytical transmission electron microscope. A new orientation imaging microscope is being installed. X-ray energy dispersive spectrometers for chemical analysis are available on all four microscopes; parallel electron energy loss spectrometers are operational on the FE-STEM and FE-HRTEM. These systems enable evaluation of local atomic bonding, as well as chemical composition in nanometer-scale regions. The FE-HRTEM has a point-to-point resolution of 1.6 {angstrom}, but the resolution can be pushed to its information limit of 1 {angstrom} by computer reconstruction of a focal series of images. HRTEM has been used to image the atomic structure of defects such as dislocations, grain boundaries, and interfaces in a variety of materials from superconductors and ferroelectrics to structural ceramics and intermetallics.

  6. High resolution low dose transmission electron microscopy real-time imaging and manipulation of nano-scale objects in the electron beam

    Science.gov (United States)

    Brown, Jr., R. Malcolm; Barnes, Zack [Austin, TX; Sawatari, Chie [Shizuoka, JP; Kondo, Tetsuo [Kukuoka, JP

    2008-02-26

    The present invention includes a method, apparatus and system for nanofabrication in which one or more target molecules are identified for manipulation with an electron beam and the one or more target molecules are manipulated with the electron beam to produce new useful materials.

  7. In Situ High-Resolution Transmission Electron Microscopy (TEM) Observation of Sn Nanoparticles on SnO2 Nanotubes Under Lithiation.

    Science.gov (United States)

    Cheong, Jun Young; Chang, Joon Ha; Kim, Sung Joo; Kim, Chanhoon; Seo, Hyeon Kook; Shin, Jae Won; Yuk, Jong Min; Lee, Jeong Yong; Kim, Il-Doo

    2017-12-01

    We trace Sn nanoparticles (NPs) produced from SnO2 nanotubes (NTs) during lithiation initialized by high energy e-beam irradiation. The growth dynamics of Sn NPs is visualized in liquid electrolytes by graphene liquid cell transmission electron microscopy. The observation reveals that Sn NPs grow on the surface of SnO2 NTs via coalescence and the final shape of agglomerated NPs is governed by surface energy of the Sn NPs and the interfacial energy between Sn NPs and SnO2 NTs. Our result will likely benefit more rational material design of the ideal interface for facile ion insertion.

  8. The extraction of gold nanoparticles from oat and wheat biomasses using sodium citrate and cetyltrimethylammonium bromide, studied by x-ray absorption spectroscopy, high-resolution transmission electron microscopy, and UV-visible spectroscopy.

    Science.gov (United States)

    Armendariz, Veronica; Parsons, Jason G; Lopez, Martha L; Peralta-Videa, Jose R; Jose-Yacaman, Miguel; Gardea-Torresdey, Jorge L

    2009-03-11

    Gold (Au) nanoparticles can be produced through the interaction of Au(III) ions with oat and wheat biomasses. This paper describes a procedure to recover gold nanoparticles from oat and wheat biomasses using cetyltrimethylammonium bromide or sodium citrate. Extracts were analyzed using UV-visible spectroscopy, high-resolution transmission electron microscopy (HRTEM), and x-ray absorption spectroscopy. The HRTEM data demonstrated that smaller nanoparticles are extracted first, followed by larger nanoparticles. In the fourth extraction, coating of chelating agents is visible on the extracted nanoparticles.

  9. The extraction of gold nanoparticles from oat and wheat biomasses using sodium citrate and cetyltrimethylammonium bromide, studied by x-ray absorption spectroscopy, high-resolution transmission electron microscopy, and UV-visible spectroscopy

    International Nuclear Information System (INIS)

    Armendariz, Veronica; Parsons, Jason G; Lopez, Martha L; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge L; Jose-Yacaman, Miguel

    2009-01-01

    Gold (Au) nanoparticles can be produced through the interaction of Au(III) ions with oat and wheat biomasses. This paper describes a procedure to recover gold nanoparticles from oat and wheat biomasses using cetyltrimethylammonium bromide or sodium citrate. Extracts were analyzed using UV-visible spectroscopy, high-resolution transmission electron microscopy (HRTEM), and x-ray absorption spectroscopy. The HRTEM data demonstrated that smaller nanoparticles are extracted first, followed by larger nanoparticles. In the fourth extraction, coating of chelating agents is visible on the extracted nanoparticles.

  10. High Resolution Electron Microscopy in Materials Science

    International Nuclear Information System (INIS)

    Amelinckx, S.

    1986-01-01

    This paper illustrates different operating modes of the electron microscope and shows the image formation in an ideal microscope. Diffraction contrast is used in the study of crystal defects, such as dislocations and planar interfaces. Methods are surveyed which give at least a rudimentary image of the lattice and therefore make use of at least two interfering beams. Special attention is given to images which also carry structural information and therefore imply the use of many beams. The underlying theory is discussed as are the theories of Van Dyck, Spence and Cowley. These are illustrated by means of a number of recent case studies

  11. A high-resolution analytical scanning transmission electron microscopy study of the early stages of spinodal decomposition in binary Fe–Cr

    International Nuclear Information System (INIS)

    Westraadt, J.E.; Olivier, E.J.; Neethling, J.H.; Hedström, P.; Odqvist, J.; Xu, X.; Steuwer, A.

    2015-01-01

    Spinodal decomposition (SD) is an important phenomenon in materials science and engineering. For example, it is considered to be responsible for the 475 °C embrittlement of stainless steels comprising the bcc (ferrite) or bct (martensite) phases. Structural characterization of the evolving minute nano-scale concentration fluctuations during SD in the Fe–Cr system is, however, a notable challenge, and has mainly been considered accessible via atom probe tomography (APT) and small-angle neutron scattering. The standard tool for nanostructure characterization, viz. transmission electron microscopy (TEM), has only been successfully applied to late stages of SD when embrittlement is already severe. However, we here demonstrate that the structural evolution in the early stages of SD in binary Fe–Cr, and alloys based on the binary, are accessible via analytical scanning TEM. An Fe–36 wt% Cr alloy aged at 500 °C for 1, 10 and 100 h is investigated using an aberration-corrected microscope and it is found that highly coherent and interconnected Cr-rich regions develop. The wavelength of decomposition is rather insensitive to the sample thickness and it is quantified to 2, 3 and 6 nm after ageing for 1, 10 and 100 h, which is in reasonable agreement with prior APT analysis. The concentration amplitude is more sensitive to the sample thickness and acquisition parameters but the TEM analysis is in good agreement with APT analysis for the longest ageing time. These findings open up for combinatorial TEM studies where both local crystallography and chemistry is required. - Highlights: • STEM-EELS analysis was successfully applied to resolve early stage SD in Fe–Cr. • Compositional wavelength measured with STEM-EELS compares well to previous ATP studies. • Compositional amplitude measured with STEM-EELS is a function of experimental parameters. • STEM-EELS allows for combinatorial studies of SD using complementary techniques.

  12. A high-resolution analytical scanning transmission electron microscopy study of the early stages of spinodal decomposition in binary Fe–Cr

    Energy Technology Data Exchange (ETDEWEB)

    Westraadt, J.E., E-mail: johan.westraadt@nmmu.ac.za [Centre for High Resolution TEM, Nelson Mandela Metropolitan University, University Way, Port Elizabeth 6031 (South Africa); Olivier, E.J.; Neethling, J.H. [Centre for High Resolution TEM, Nelson Mandela Metropolitan University, University Way, Port Elizabeth 6031 (South Africa); Hedström, P.; Odqvist, J.; Xu, X. [Dept. Materials Science and Engineering, KTH Royal Institute of Technology, Brinellvägen 23, 10044 Stockholm (Sweden); Steuwer, A. [Nelson Mandela Metropolitan University, Gardham Av., Port Elizabeth 6031 (South Africa)

    2015-11-15

    Spinodal decomposition (SD) is an important phenomenon in materials science and engineering. For example, it is considered to be responsible for the 475 °C embrittlement of stainless steels comprising the bcc (ferrite) or bct (martensite) phases. Structural characterization of the evolving minute nano-scale concentration fluctuations during SD in the Fe–Cr system is, however, a notable challenge, and has mainly been considered accessible via atom probe tomography (APT) and small-angle neutron scattering. The standard tool for nanostructure characterization, viz. transmission electron microscopy (TEM), has only been successfully applied to late stages of SD when embrittlement is already severe. However, we here demonstrate that the structural evolution in the early stages of SD in binary Fe–Cr, and alloys based on the binary, are accessible via analytical scanning TEM. An Fe–36 wt% Cr alloy aged at 500 °C for 1, 10 and 100 h is investigated using an aberration-corrected microscope and it is found that highly coherent and interconnected Cr-rich regions develop. The wavelength of decomposition is rather insensitive to the sample thickness and it is quantified to 2, 3 and 6 nm after ageing for 1, 10 and 100 h, which is in reasonable agreement with prior APT analysis. The concentration amplitude is more sensitive to the sample thickness and acquisition parameters but the TEM analysis is in good agreement with APT analysis for the longest ageing time. These findings open up for combinatorial TEM studies where both local crystallography and chemistry is required. - Highlights: • STEM-EELS analysis was successfully applied to resolve early stage SD in Fe–Cr. • Compositional wavelength measured with STEM-EELS compares well to previous ATP studies. • Compositional amplitude measured with STEM-EELS is a function of experimental parameters. • STEM-EELS allows for combinatorial studies of SD using complementary techniques.

  13. Human enamel structure studied by high resolution electron microscopy

    International Nuclear Information System (INIS)

    Wen, S.L.

    1989-01-01

    Human enamel structural features are characterized by high resolution electron microscopy. The human enamel consists of polycrystals with a structure similar to Ca10(PO4)6(OH)2. This article describes the structural features of human enamel crystal at atomic and nanometer level. Besides the structural description, a great number of high resolution images are included. Research into the carious process in human enamel is very important for human beings. This article firstly describes the initiation of caries in enamel crystal at atomic and unit-cell level and secondly describes the further steps of caries with structural and chemical demineralization. The demineralization in fact, is the origin of caries in human enamel. The remineralization of carious areas in human enamel has drawn more and more attention as its potential application is realized. This process has been revealed by high resolution electron microscopy in detail in this article. On the other hand, the radiation effects on the structure of human enamel are also characterized by high resolution electron microscopy. In order to reveal this phenomenon clearly, a great number of electron micrographs have been shown, and a physical mechanism is proposed. 26 references

  14. Amorphous-like interfacial layer between a high-Tc superconducting Tl-1223 film and a Ag substrate examined by high-voltage high-resolution transmission electron microscopy

    International Nuclear Information System (INIS)

    Kim, Bongjun; Kim, Hyuntak; Nagai, Takuro; Matsui, Yoshio; Horiuchi, Shigeo; Jeong, Daeyeong; Deinhofer, Christian; Gritzner, Gerhard; Kim, Youngmin; Kim, Younjoong

    2006-01-01

    The thin amorphous-like layer, formed at the interface between a high-T c superconducting (Tl 0.5 , Pb 0.5 )(Sr 0.8 , Ba 0.2 )Ca 2 Cu 3 O y (Tl-1223) film and a Ag substrate during heating at 910 .deg. C, has been examined by using high-voltage high-resolution transmission electron microscopy. The interfacial layer is less than 10 nm in thickness. It contacts the (001) plane of Tl-1223 and the (113) or (133) planes of Ag in most cases. Its composition is similar to that of Tl-1223, except for the inclusion of a substantial amount of Ag. Its formation proceeds by diffusion of Ag into Tl-1223, during which a structure change first occurs at the layer of CuO 2 + Ca planes. The Tl(Pb)O + the Sr(Ba)O layers are then destroyed to cause the total structure to become amorphous-like. Furthermore, we have found that it is formed under an irradiation of highly energetic electrons.

  15. Amorphous-like interfacial layer between a high-T{sub c} superconducting Tl-1223 film and a Ag substrate examined by high-voltage high-resolution transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bongjun; Kim, Hyuntak [Electronics and Tele-Communications Research Institute, Daejeon (Korea, Republic of); Nagai, Takuro; Matsui, Yoshio [National Institute for Materials Science, Tsukuba, Ibaraki (Japan); Horiuchi, Shigeo; Jeong, Daeyeong [Electrotechnology Research Institute, Changwon (Korea, Republic of); Deinhofer, Christian; Gritzner, Gerhard [Johannes Kepler University, Linz (Austria); Kim, Youngmin; Kim, Younjoong [Electron Microscopy Team, Korea Basic Science Institute, Daejeon (Korea, Republic of)

    2006-05-15

    The thin amorphous-like layer, formed at the interface between a high-T{sub c} superconducting (Tl{sub 0.5}, Pb{sub 0.5})(Sr{sub 0.8}, Ba{sub 0.2})Ca{sub 2}Cu{sub 3}O{sub y} (Tl-1223) film and a Ag substrate during heating at 910 .deg. C, has been examined by using high-voltage high-resolution transmission electron microscopy. The interfacial layer is less than 10 nm in thickness. It contacts the (001) plane of Tl-1223 and the (113) or (133) planes of Ag in most cases. Its composition is similar to that of Tl-1223, except for the inclusion of a substantial amount of Ag. Its formation proceeds by diffusion of Ag into Tl-1223, during which a structure change first occurs at the layer of CuO{sub 2} + Ca planes. The Tl(Pb)O + the Sr(Ba)O layers are then destroyed to cause the total structure to become amorphous-like. Furthermore, we have found that it is formed under an irradiation of highly energetic electrons.

  16. High-resolution observation by double-biprism electron holography

    International Nuclear Information System (INIS)

    Harada, Ken; Tonomura, Akira; Matsuda, Tsuyoshi; Akashi, Tetsuya; Togawa, Yoshihiko

    2004-01-01

    High-resolution electron holography has been achieved by using a double-biprism interferometer implemented on a 1 MV field emission electron microscope. The interferometer was installed behind the first magnifying lens to narrow carrier fringes and thus enabled complete separation of sideband Fourier spectrum from center band in reconstruction process. Holograms of Au fine particles and single-crystalline thin films with the finest fringe spacing of 4.2 pm were recorded and reconstructed. The overall holography system including the reconstruction process performed well for holograms in which carrier fringes had a spacing of around 10 pm. High-resolution lattice images of the amplitude and phase were clearly reconstructed without mixing of the center band and sideband information. Additionally, entire holograms were recorded without Fresnel fringes normally generated by the filament electrode of the biprism, and the holograms were thus reconstructed without the artifacts caused by Fresnel fringes

  17. Precision crystal alignment for high-resolution electron microscope imaging

    International Nuclear Information System (INIS)

    Wood, G.J.; Beeching, M.J.

    1990-01-01

    One of the more difficult tasks involved in obtaining quality high-resolution electron micrographs is the precise alignment of a specimen into the required zone. The current accepted procedure, which involves changing to diffraction mode and searching for symmetric point diffraction pattern, is insensitive to small amounts of misalignment and at best qualitative. On-line analysis of the fourier space representation of the image, both for determining and correcting crystal tilt, is investigated. 8 refs., 42 figs

  18. Environmental high resolution electron microscopy and applications to chemical science

    OpenAIRE

    Boyes, Edward; Gai, Pratibha

    2017-01-01

    An environmental cell high resolution electron microscope (EHREM) has been developed for in situ studies of dynamic chemical reactions on the atomic scale. It allows access to metastable intermediate phases of catalysts and to sequences of reversible microstructural and chemical development associated with the activation, deactivation and poisoning of a catalyst. Materials transported through air can be restored or recreated and samples damaged, e.g. by dehydration, by the usual vacuum enviro...

  19. High-Resolution Electronics: Spontaneous Patterning of High-Resolution Electronics via Parallel Vacuum Ultraviolet (Adv. Mater. 31/2016).

    Science.gov (United States)

    Liu, Xuying; Kanehara, Masayuki; Liu, Chuan; Sakamoto, Kenji; Yasuda, Takeshi; Takeya, Jun; Minari, Takeo

    2016-08-01

    On page 6568, T. Minari and co-workers describe spontaneous patterning based on the parallel vacuum ultraviolet (PVUV) technique, enabling the homogeneous integration of complex, high-resolution electronic circuits, even on large-scale, flexible, transparent substrates. Irradiation of PVUV to the hydrophobic polymer surface precisely renders the selected surface into highly wettable regions with sharply defined boundaries, which spontaneously guides a metal nanoparticle ink into a series of circuit lines and gaps with the widths down to a resolution of 1 μm. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. High-resolution electron microscopy and its applications.

    Science.gov (United States)

    Li, F H

    1987-12-01

    A review of research on high-resolution electron microscopy (HREM) carried out at the Institute of Physics, the Chinese Academy of Sciences, is presented. Apart from the direct observation of crystal and quasicrystal defects for some alloys, oxides, minerals, etc., and the structure determination for some minute crystals, an approximate image-contrast theory named pseudo-weak-phase object approximation (PWPOA), which shows the image contrast change with crystal thickness, is described. Within the framework of PWPOA, the image contrast of lithium ions in the crystal of R-Li2Ti3O7 has been observed. The usefulness of diffraction analysis techniques such as the direct method and Patterson method in HREM is discussed. Image deconvolution and resolution enhancement for weak-phase objects by use of the direct method are illustrated. In addition, preliminary results of image restoration for thick crystals are given.

  1. Polystyrene negative resist for high-resolution electron beam lithography

    Directory of Open Access Journals (Sweden)

    Ma Siqi

    2011-01-01

    Full Text Available Abstract We studied the exposure behavior of low molecular weight polystyrene as a negative tone electron beam lithography (EBL resist, with the goal of finding the ultimate achievable resolution. It demonstrated fairly well-defined patterning of a 20-nm period line array and a 15-nm period dot array, which are the densest patterns ever achieved using organic EBL resists. Such dense patterns can be achieved both at 20 and 5 keV beam energies using different developers. In addition to its ultra-high resolution capability, polystyrene is a simple and low-cost resist with easy process control and practically unlimited shelf life. It is also considerably more resistant to dry etching than PMMA. With a low sensitivity, it would find applications where negative resist is desired and throughput is not a major concern.

  2. Refinement procedure for the image alignment in high-resolution electron tomography

    International Nuclear Information System (INIS)

    Houben, L.; Bar Sadan, M.

    2011-01-01

    High-resolution electron tomography from a tilt series of transmission electron microscopy images requires an accurate image alignment procedure in order to maximise the resolution of the tomogram. This is the case in particular for ultra-high resolution where even very small misalignments between individual images can dramatically reduce the fidelity of the resultant reconstruction. A tomographic-reconstruction based and marker-free method is proposed, which uses an iterative optimisation of the tomogram resolution. The method utilises a search algorithm that maximises the contrast in tomogram sub-volumes. Unlike conventional cross-correlation analysis it provides the required correlation over a large tilt angle separation and guarantees a consistent alignment of images for the full range of object tilt angles. An assessment based on experimental reconstructions shows that the marker-free procedure is competitive to the reference of marker-based procedures at lower resolution and yields sub-pixel accuracy even for simulated high-resolution data. -- Highlights: → Alignment procedure for electron tomography based on iterative tomogram contrast optimisation. → Marker-free, independent of object, little user interaction. → Accuracy competitive with fiducial marker methods and suited for high-resolution tomography.

  3. High resolution transmission spectroscopy as a diagnostic for Jovian exoplanet atmospheres: constraints from theoretical models

    Energy Technology Data Exchange (ETDEWEB)

    Kempton, Eliza M.-R. [Department of Physics, Grinnell College, Grinnell, IA 50112 (United States); Perna, Rosalba [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States); Heng, Kevin, E-mail: kemptone@grinnell.edu [University of Bern, Center for Space and Habitability, Sidlerstrasse 5, CH-3012 Bern (Switzerland)

    2014-11-01

    We present high resolution transmission spectra of giant planet atmospheres from a coupled three-dimensional (3D) atmospheric dynamics and transmission spectrum model that includes Doppler shifts which arise from winds and planetary motion. We model Jovian planets covering more than two orders of magnitude in incident flux, corresponding to planets with 0.9-55 day orbital periods around solar-type stars. The results of our 3D dynamical models reveal certain aspects of high resolution transmission spectra that are not present in simple one-dimensional (1D) models. We find that the hottest planets experience strong substellar to anti-stellar (SSAS) winds, resulting in transmission spectra with net blueshifts of up to 3 km s{sup –1}, whereas less irradiated planets show almost no net Doppler shifts. We find only minor differences between transmission spectra for atmospheres with temperature inversions and those without. Compared to 1D models, peak line strengths are significantly reduced for the hottest atmospheres owing to Doppler broadening from a combination of rotation (which is faster for close-in planets under the assumption of tidal locking) and atmospheric winds. Finally, high resolution transmission spectra may be useful in studying the atmospheres of exoplanets with optically thick clouds since line cores for very strong transitions should remain optically thick to very high altitude. High resolution transmission spectra are an excellent observational test for the validity of 3D atmospheric dynamics models, because they provide a direct probe of wind structures and heat circulation. Ground-based exoplanet spectroscopy is currently on the verge of being able to verify some of our modeling predictions, most notably the dependence of SSAS winds on insolation. We caution that interpretation of high resolution transmission spectra based on 1D atmospheric models may be inadequate, as 3D atmospheric motions can produce a noticeable effect on the absorption

  4. Modelling high-resolution electron microscopy based on core-loss spectroscopy

    International Nuclear Information System (INIS)

    Allen, L.J.; Findlay, S.D.; Oxley, M.P.; Witte, C.; Zaluzec, N.J.

    2006-01-01

    There are a number of factors affecting the formation of images based on core-loss spectroscopy in high-resolution electron microscopy. We demonstrate unambiguously the need to use a full nonlocal description of the effective core-loss interaction for experimental results obtained from high angular resolution electron channelling electron spectroscopy. The implications of this model are investigated for atomic resolution scanning transmission electron microscopy. Simulations are used to demonstrate that core-loss spectroscopy images formed using fine probes proposed for future microscopes can result in images that do not correspond visually with the structure that has led to their formation. In this context, we also examine the effect of varying detector geometries. The importance of the contribution to core-loss spectroscopy images by dechannelled or diffusely scattered electrons is reiterated here

  5. A high resolution electron microscopy investigation of curvature in multilayer graphite sheets

    International Nuclear Information System (INIS)

    Wang Zhenxia; Hu Jun; Wang Wenmin; Yu Guoqing

    1998-01-01

    Here the authors report a carbon sample generated by ultrasonic wave high oriented pyrolytic graphite (HOPG) in ethanol, water or ethanol-water mixed solution. High resolution transmission electron microscopy (HRTEM) revealed many multilayer graphite sheets with a total curved angle that is multiples of θ 0 (= 30 degree C). Close examination of the micrographs showed that the curvature is accomplished by bending the lattice planes. A possible explanation for the curvature in multilayer graphite sheets is discussed based on the conformation of graphite symmetry axes and the formation of sp 3 -like line defects in the sp 2 graphitic network

  6. Refinement procedure for the image alignment in high-resolution electron tomography.

    Science.gov (United States)

    Houben, L; Bar Sadan, M

    2011-01-01

    High-resolution electron tomography from a tilt series of transmission electron microscopy images requires an accurate image alignment procedure in order to maximise the resolution of the tomogram. This is the case in particular for ultra-high resolution where even very small misalignments between individual images can dramatically reduce the fidelity of the resultant reconstruction. A tomographic-reconstruction based and marker-free method is proposed, which uses an iterative optimisation of the tomogram resolution. The method utilises a search algorithm that maximises the contrast in tomogram sub-volumes. Unlike conventional cross-correlation analysis it provides the required correlation over a large tilt angle separation and guarantees a consistent alignment of images for the full range of object tilt angles. An assessment based on experimental reconstructions shows that the marker-free procedure is competitive to the reference of marker-based procedures at lower resolution and yields sub-pixel accuracy even for simulated high-resolution data. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Electron-optical design parameters for a high-resolution electron monochromator

    International Nuclear Information System (INIS)

    Tanaka, H.; Huebner, R.H.

    1976-01-01

    Detailed design parameters of a new, high-resolution electron monochromator are presented. The design utilizes a hemispherical filter as the energy-dispersing element and combines both cylindrical and aperture electrostatic lenses to accelerate, decelerate, transport, and focus the electron beam from the cathode to the interaction region

  8. Characterisation of nanoparticles by means of high-resolution SEM/EDS in transmission mode

    International Nuclear Information System (INIS)

    Hodoroaba, V-D; Rades, S; Mielke, J; Ortel, E; Salge, T; Schmidt, R

    2016-01-01

    Advances in scanning electron microscopy (SEM) enable the high-resolution imaging of single nanoparticles (NPs) with sizes well below 10 nm. The SEM analysis in transmission mode (T-SEM) of NPs on thin film supports has many benefits when compared to the analysis of NPs on bulk substrates. The enhanced material (mass - thickness) contrast of the T-SEM imaging mode is well suited for in-depth and, particularly valuable, to very accurate, traceable, lateral dimensional measurements of NPs. Compared to samples prepared on bulk substrates, T-SEM with energy dispersive X-ray spectroscopy (EDS) achieves a drastically improved spatial resolution of the emitted X-rays. The poor signal-to-noise ratio of the X-ray spectra emitted by a single nanoparticle (NP) can be improved by the use of high-sensitivity (high collection solid angle) silicon drift (SDD), energy-dispersive X-ray spectrometers (EDS). The EDS spectral imaging of a single NP with a spatial resolution below 10 nm has become possible. This is demonstrated by means of various examples of nanostructures. Advanced data processing of T-SEM/EDS results sets the stage for the automated classification of NPs by feature analysis. This method combines the detection of morphological structures of interest by image processing of T-SEM micrographs with the chemical classification by EDS. (paper)

  9. Investigations and characterization of the microstructure of special ceramic materials using the high-resolution electron microscope

    International Nuclear Information System (INIS)

    Kirn, M.

    1979-01-01

    The possibilities to characterize phases and microstructures by direct lattice imaging are indicated in the following work. Ceramic materials are particularly suitable for this as these exhibit a high mechanical stability in the investigation in the transmission electron microscope. First of all the fundamentals of the high-resolution electron microscopy are introduced and the various resulting possibilities to characterize microstructures are presented. A report then follows on experimental observations on undisturbed crystals of special ceramics on a Si 3 N 4 basis. Furthermore, it is shown that the high-resolution electron microscope provides valuable contributions to the determination of structure, in particular of twin variants. Finally, revealing information on the structure of the interfaces was obtained with the help of high-resolution electron microscopy. (orig./IHOE) [de

  10. Electron beam fabrication and characterization of high-resolution magnetic force microscopy tips

    Science.gov (United States)

    Rührig, M.; Porthun, S.; Lodder, J. C.; McVitie, S.; Heyderman, L. J.; Johnston, A. B.; Chapman, J. N.

    1996-03-01

    The stray field, magnetic microstructure, and switching behavior of high-resolution electron beam fabricated thin film tips for magnetic force microscopy (MFM) are investigated with different imaging modes in a transmission electron microscope (TEM). As the tiny smooth carbon needles covered with a thermally evaporated magnetic thin film are transparent to the electron energies used in these TEMs it is possible to observe both the external stray field emanating from the tips as well as their internal domain structure. The experiments confirm the basic features of electron beam fabricated thin film tips concluded from various MFM observations using these tips. Only a weak but highly concentrated stray field is observed emanating from the immediate apex region of the tip, consistent with their capability for high resolution. It also supports the negligible perturbation of the magnetization sample due to the tip stray field observed in MFM experiments. Investigation of the magnetization distributions within the tips, as well as preliminary magnetizing experiments, confirm a preferred single domain state of the high aspect ratio tips. To exclude artefacts of the observation techniques both nonmagnetic tips and those supporting different magnetization states are used for comparison.

  11. Wide-range high-resolution transmission electron microscopy reveals morphological and distributional changes of endomembrane compartments during log to stationary transition of growth phase in tobacco BY-2 cells.

    Science.gov (United States)

    Toyooka, Kiminori; Sato, Mayuko; Kutsuna, Natsumaro; Higaki, Takumi; Sawaki, Fumie; Wakazaki, Mayumi; Goto, Yumi; Hasezawa, Seiichiro; Nagata, Noriko; Matsuoka, Ken

    2014-09-01

    Rapid growth of plant cells by cell division and expansion requires an endomembrane trafficking system. The endomembrane compartments, such as the Golgi stacks, endosome and vesicles, are important in the synthesis and trafficking of cell wall materials during cell elongation. However, changes in the morphology, distribution and number of these compartments during the different stages of cell proliferation and differentiation have not yet been clarified. In this study, we examined these changes at the ultrastructural level in tobacco Bright yellow 2 (BY-2) cells during the log and stationary phases of growth. We analyzed images of the BY-2 cells prepared by the high-pressure freezing/freeze substitution technique with the aid of an auto-acquisition transmission electron microscope system. We quantified the distribution of secretory and endosomal compartments in longitudinal sections of whole cells by using wide-range gigapixel-class images obtained by merging thousands of transmission electron micrographs. During the log phase, all Golgi stacks were composed of several thick cisternae. Approximately 20 vesicle clusters (VCs), including the trans-Golgi network and secretory vesicle cluster, were observed throughout the cell. In the stationary-phase cells, Golgi stacks were thin with small cisternae, and only a few VCs were observed. Nearly the same number of multivesicular body and small high-density vesicles were observed in both the stationary and log phases. Results from electron microscopy and live fluorescence imaging indicate that the morphology and distribution of secretory-related compartments dramatically change when cells transition from log to stationary phases of growth. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  12. Dose-dependent high-resolution electron ptychography

    International Nuclear Information System (INIS)

    D'Alfonso, A. J.; Allen, L. J.; Sawada, H.; Kirkland, A. I.

    2016-01-01

    Recent reports of electron ptychography at atomic resolution have ushered in a new era of coherent diffractive imaging in the context of electron microscopy. We report and discuss electron ptychography under variable electron dose conditions, exploring the prospects of an approach which has considerable potential for imaging where low dose is needed

  13. Evidence of sharp and diffuse domain walls in BiFeO3 by means of unit-cell-wise strain and polarization maps obtained with high resolution scanning transmission electron microscopy.

    Science.gov (United States)

    Lubk, A; Rossell, M D; Seidel, J; He, Q; Yang, S Y; Chu, Y H; Ramesh, R; Hÿtch, M J; Snoeck, E

    2012-07-27

    Domain walls (DWs) substantially influence a large number of applications involving ferroelectric materials due to their limited mobility when shifted during polarization switching. The discovery of greatly enhanced conduction at BiFeO(3) DWs has highlighted yet another role of DWs as a local material state with unique properties. However, the lack of precise information on the local atomic structure is still hampering microscopical understanding of DW properties. Here, we examine the atomic structure of BiFeO(3) 109° DWs with pm precision by a combination of high-angle annular dark-field scanning transmission electron microscopy and a dedicated structural analysis. By measuring simultaneously local polarization and strain, we provide direct experimental proof for the straight DW structure predicted by ab initio calculations as well as the recently proposed theory of diffuse DWs, thus resolving a long-standing discrepancy between experimentally measured and theoretically predicted DW mobilities.

  14. High resolution electron microscopy and electron diffraction of YBa2Cu3O(7-x)

    International Nuclear Information System (INIS)

    Krakow, W.; Shaw, T.M.

    1988-01-01

    Experimental high resolution electron micrographs and computer simulation experiments have been used to evaluate the visibility of the atomic constituents of YBa 2 Cu 3 O(7-x). In practice, the detection of oxygen has not been possible in contradiction to that predicted by modelling of perfect crystalline material. Preliminary computer experiments of the electron diffraction patterns when oxygen vacancies are introduced on the Cu-O sheets separating Ba layers show the diffuse streaks characteristic of short range ordering. 7 references

  15. High resolution electron attachment to molecules of atmospheric relevance

    International Nuclear Information System (INIS)

    Senn, G.

    2000-10-01

    This Ph.D. thesis is divided into three parts. The first is an introduction into the field of electron attachment. In the second part the experimental apparatus is described, and in the third part the results are presented. In the present thesis molecules were chosen for our investigations that are not only of academic interest but that also play an important role for applications or even the life on this planet. All the molecules studied in this work are of atmospheric relevance. NO, and OClO, are involved in the ozone depletion of the stratosphere. The D-layer of the ionosphere is an upper boundary of the ozone layer, therefore the interaction of the electrons from the D-layer with O 3 might play an important role for the chemistry in that part of the atmosphere. Especially the interaction of slow electrons (that will be present in the D-layer in large numbers) with ozone was emphasized in the present study. The production of O - and O 2 - by dissociative electron attachment to ozone was measured for incident electron energies between 0 and 10eV. A previously unobserved sharp structure was discovered in the formation of O - ions for electrons with zero kinetic energy. This additional cross section peak has important consequences for the role of ozone in the anion formation process in the ionosphere. Since OClO is a night time reservoir for chlorine atoms (Cl) and chlorine monoxide (ClO) both of which play a critical role in the depletion of the stratospheric ozone, we have studied negative ion formation following electron impact (0-10eV) to OClO. Despite its atmospheric relevance the mechanism of dissociative electron attachment (DEA) to NO is still a matter of controversy. DEA was studied at high energy resolution and with a kinetic-energy analysis of the O - fragment in two independent crossed electron-molecular-beam experiments. The DEA cross section exhibits a vertical onset near 7.45eV that corresponds to the energy threshold of the DEA channel O - ( 2 P

  16. High Resolution Separations and Improved Ion Production and Transmission in Metabolomics

    Energy Technology Data Exchange (ETDEWEB)

    Metz, Thomas O.; Page, Jason S.; Baker, Erin Shammel; Tang, Keqi; Ding, Jie; Shen, Yufeng; Smith, Richard D.

    2008-03-31

    The goal of metabolomics experiments is the detection and quantitation of as many sample components as reasonably possible in order to identify “features” that can be used to characterize the samples under study. When utilizing electrospray ionization to produce ions for analysis by mass spectrometry (MS), it is imperative that metabolome sample constituents be efficiently separated prior to ion production, in order to minimize the phenomenon of ionization suppression. Similarly, optimization of the MS inlet can lead to increased measurement sensitivity. This review will focus on the role of high resolution liquid chromatography (LC) separations in conjunction with improved ion production and transmission for LC-MS-based metabolomics.

  17. High resolution electron microscopy study of as-prepared and annealed tungsten-carbon multilayers

    International Nuclear Information System (INIS)

    Nguyen, T.D.; Gronsky, R.; Kortright, J.B.

    1988-12-01

    A series of sputtered tungsten-carbon multilayer structures with periods ranging from 2 to 12 nm in the as-prepared state and after annealing at 500/degree/C for 4 hours has been studied with high resolution transmission electron microscopy. The evolution with annealing of the microstructure of these multilayers depends on their period. As-prepared structures appear predominantly amorphous from TEM imaging and diffraction. Annealing results in crystallization of the W-rich layers into WC in the larger period samples, and less complete or no crystallization in the smaller period samples. X-ray scattering reveals that annealing expands the period in a systematic way. The layers remain remarkably well-defined after annealing under these conditions. 12 refs., 4 figs., 1 tab

  18. Electron Temperatures in W51 Complex from High Resolution, Low ...

    Indian Academy of Sciences (India)

    2001-03-09

    Mar 9, 2001 ... kinematics and local thermodynamic equilibrium (LTE) electron temperature (Te) of this region. H109α RRL observations by Wilsonet al.(1970) with a resolution of 4 and by Pankonin et al. (1979) with a resolution of 2.6 show that Te ∼ 6000 K in G49.5-0.4. Lower frequency observations for H137β and ...

  19. High-resolution electron microscopy of detonation nanodiamond

    International Nuclear Information System (INIS)

    Iakoubovskii, K; Mitsuishi, K; Furuya, K

    2008-01-01

    The structure of individual nanodiamond grains produced by the detonation of carbon-based explosives has been studied with a high-vacuum aberration-corrected electron microscope. Many grains show a well-resolved cubic diamond lattice with negligible contamination, thereby demonstrating that the non-diamond shell, universally observed on nanodiamond particles, could be intrinsic to the preparation process rather than to the nanosized diamond itself. The strength of the adhesion between the nanodiamond grains, and the possibility of their patterning with sub-nanometer precision, are also demonstrated

  20. High-resolution electron microscopy of detonation nanodiamond

    Energy Technology Data Exchange (ETDEWEB)

    Iakoubovskii, K; Mitsuishi, K [Quantum Dot Research Center, National Institute for Materials Science, 3-13 Sakura, Tsukuba 305-0005 (Japan); Furuya, K [High Voltage Microscopy Station, National Institute for Materials Science, 3-13 Sakura, Tsukuba 305-0005 (Japan)], E-mail: Iakoubovskii.Konstantin@nims.go.jp

    2008-04-16

    The structure of individual nanodiamond grains produced by the detonation of carbon-based explosives has been studied with a high-vacuum aberration-corrected electron microscope. Many grains show a well-resolved cubic diamond lattice with negligible contamination, thereby demonstrating that the non-diamond shell, universally observed on nanodiamond particles, could be intrinsic to the preparation process rather than to the nanosized diamond itself. The strength of the adhesion between the nanodiamond grains, and the possibility of their patterning with sub-nanometer precision, are also demonstrated.

  1. Construction of a high resolution electron beam profile monitor

    International Nuclear Information System (INIS)

    Norem, J.; Dawson, J.; Haberichter, W.; Novak, W.; Reed, L.; Yang, X.F.

    1993-01-01

    Bremsstrahlung from an electron beam on a heavy target can be used to image the beam profile using collimators and slits. The limiting resolution using this system is determined by Fresnel diffraction, and is ∼ √(λd/2), where λ is the photon wavelength and d is determined by the linear dimensions of the system. For linear colliders this resolution could be a few nm. The highest resolution requires detectors which see only high energy, (small λ), photons, and this is accomplished by converting photons to pairs, and detecting Cherenkov light in a nearly forward angle with a CCD detector or streak camera. Tests are planned at the Argonne APS and SLAC FFTB

  2. High-Resolution Measurements of Low-Energy Conversion Electrons

    CERN Multimedia

    Gizon, A; Putaux, J

    2002-01-01

    Measurements of low-energy internal conversion electrons have been performed with high energy resolution in some N = 105 odd and odd-odd nuclei using a semi-circular spectrograph associated to a specific tape transport system. These experiments aimed to answer the following questions~: \\begin{itemize} \\item Do M3 isomeric transitions exist in $^{183}$Pt and $^{181}$Os, isotones of $^{184}$Au~? \\item Are the neutron configurations proposed to describe the isomeric and ground states of $^{184}$Au right or wrong~? \\item Does it exist an isomeric state in $^{182}$Ir, isotone of $^{181}$Os, $^{183}$Pt and $^{184}$Au~? \\item What are the spin and parity values of the excited states of $^{182}$Ir~? \\end{itemize} In $^{183}$Pt, the 35.0 keV M3 isomeric transition has been clearly observed and the reduced transition probability has been determined. The deduced hindrance factor is close to that observed in the neighbouring odd-odd $^{184}$Au nucleus. This confirms the neutron configurations previously proposed for the ...

  3. Method for local temperature measurement in a nanoreactor for in situ high-resolution electron microscopy.

    Science.gov (United States)

    Vendelbo, S B; Kooyman, P J; Creemer, J F; Morana, B; Mele, L; Dona, P; Nelissen, B J; Helveg, S

    2013-10-01

    In situ high-resolution transmission electron microscopy (TEM) of solids under reactive gas conditions can be facilitated by microelectromechanical system devices called nanoreactors. These nanoreactors are windowed cells containing nanoliter volumes of gas at ambient pressures and elevated temperatures. However, due to the high spatial confinement of the reaction environment, traditional methods for measuring process parameters, such as the local temperature, are difficult to apply. To address this issue, we devise an electron energy loss spectroscopy (EELS) method that probes the local temperature of the reaction volume under inspection by the electron beam. The local gas density, as measured using quantitative EELS, is combined with the inherent relation between gas density and temperature, as described by the ideal gas law, to obtain the local temperature. Using this method we determined the temperature gradient in a nanoreactor in situ, while the average, global temperature was monitored by a traditional measurement of the electrical resistivity of the heater. The local gas temperatures had a maximum of 56 °C deviation from the global heater values under the applied conditions. The local temperatures, obtained with the proposed method, are in good agreement with predictions from an analytical model. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. High-Resolution Light Transmission Spectroscopy of Nanoparticles in Real Time

    Science.gov (United States)

    Tanner, Carol; Sun, Nan; Deatsch, Alison; Li, Frank; Ruggiero, Steven

    2017-04-01

    As implemented here, Light Transmission Spectroscopy (LTS) is a high-resolution real-time technique for eliminating spectral noise and systematic effects in wide band spectroscopic measurements of nanoparticles. In this work, we combine LTS with spectral inversion for the purpose of characterizing the size, shape, and number of nanoparticles in solution. The apparatus employs a wide-band multi-wavelength light source and grating spectrometers coupled to CCD detectors. The light source ranges from 210 to 2000 nm, and the wavelength dependent light detection system ranges from 200 to 1100 nm with model the total extinction cross-section, and spectral inversion is employed to obtain quantitative particle size distributions. Discussed are the precision, accuracy, resolution, and sensitivity of our results. The technique is quite versatile and can be applied to spectroscopic investigations where wideband, accurate, low-noise, real-time spectra are desired. University of Notre Dame Office of Research, College of Science, Department of Physics, and USDA.

  5. High-resolution EELS investigation of the electronic structure of ilmenites

    NARCIS (Netherlands)

    Radtke, G.; Lazar, S.; Botton, G.A.

    2006-01-01

    The electronic structure of a series of compounds belonging to the ilmenite family is investigated using high resolution electron energy loss spectroscopy (EELS). The energy loss near edge structure (ELNES) of the O-K, Ti-L23 and transition metal L23 edges have been recorded in MnTiO3, FeTiO3,

  6. Atom-counting in High Resolution Electron Microscopy:TEM or STEM - That's the question.

    Science.gov (United States)

    Gonnissen, J; De Backer, A; den Dekker, A J; Sijbers, J; Van Aert, S

    2017-03-01

    In this work, a recently developed quantitative approach based on the principles of detection theory is used in order to determine the possibilities and limitations of High Resolution Scanning Transmission Electron Microscopy (HR STEM) and HR TEM for atom-counting. So far, HR STEM has been shown to be an appropriate imaging mode to count the number of atoms in a projected atomic column. Recently, it has been demonstrated that HR TEM, when using negative spherical aberration imaging, is suitable for atom-counting as well. The capabilities of both imaging techniques are investigated and compared using the probability of error as a criterion. It is shown that for the same incoming electron dose, HR STEM outperforms HR TEM under common practice standards, i.e. when the decision is based on the probability function of the peak intensities in HR TEM and of the scattering cross-sections in HR STEM. If the atom-counting decision is based on the joint probability function of the image pixel values, the dependence of all image pixel intensities as a function of thickness should be known accurately. Under this assumption, the probability of error may decrease significantly for atom-counting in HR TEM and may, in theory, become lower as compared to HR STEM under the predicted optimal experimental settings. However, the commonly used standard for atom-counting in HR STEM leads to a high performance and has been shown to work in practice. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. High-resolution whole-brain diffusion MRI at 7T using radiofrequency parallel transmission.

    Science.gov (United States)

    Wu, Xiaoping; Auerbach, Edward J; Vu, An T; Moeller, Steen; Lenglet, Christophe; Schmitter, Sebastian; Van de Moortele, Pierre-François; Yacoub, Essa; Uğurbil, Kâmil

    2018-03-30

    Investigating the utility of RF parallel transmission (pTx) for Human Connectome Project (HCP)-style whole-brain diffusion MRI (dMRI) data at 7 Tesla (7T). Healthy subjects were scanned in pTx and single-transmit (1Tx) modes. Multiband (MB), single-spoke pTx pulses were designed to image sagittal slices. HCP-style dMRI data (i.e., 1.05-mm resolutions, MB2, b-values = 1000/2000 s/mm 2 , 286 images and 40-min scan) and data with higher accelerations (MB3 and MB4) were acquired with pTx. pTx significantly improved flip-angle detected signal uniformity across the brain, yielding ∼19% increase in temporal SNR (tSNR) averaged over the brain relative to 1Tx. This allowed significantly enhanced estimation of multiple fiber orientations (with ∼21% decrease in dispersion) in HCP-style 7T dMRI datasets. Additionally, pTx pulses achieved substantially lower power deposition, permitting higher accelerations, enabling collection of the same data in 2/3 and 1/2 the scan time or of more data in the same scan time. pTx provides a solution to two major limitations for slice-accelerated high-resolution whole-brain dMRI at 7T; it improves flip-angle uniformity, and enables higher slice acceleration relative to current state-of-the-art. As such, pTx provides significant advantages for rapid acquisition of high-quality, high-resolution truly whole-brain dMRI data. © 2018 International Society for Magnetic Resonance in Medicine.

  8. Neutron widths for 236U from high resolution transmission measurements at a 100M flightpath

    International Nuclear Information System (INIS)

    Carraro, G.; Brusegan, A.

    1975-01-01

    A series of neutron transmission measurements has been performed on 236 U aiming at a determination of the resonance parameters and their statistical properties. The analysis range covered neutron energies from 40eV to 4.1 keV. The experiments were carried out at about 100 m flightpath of the 80 MeV electron linear accelerator of CBNM using a 10 B slab-NaI detector and 2 236 U-oxyde samples on loan from the USAEC. A table displays the details of 6 experimental runs, 3 of which were arranged in such a way that the effect of the 235 U and 238 U impurities in the sample on the transmission was automatically compensated

  9. Transmission electron microscope studies of extraterrestrial materials

    Science.gov (United States)

    Keller, Lindsay P.

    1995-01-01

    Transmission Electron Microscopy, X-Ray spectrometry and electron-energy-loss spectroscopy are used to analyse carbon in interplanetary dust particles. Optical micrographs are shown depicting cross sections of the dust particles embedded in sulphur. Selected-area electron diffraction patterns are shown. Transmission Electron Microscope specimens of lunar soil were prepared using two methods: ion-milling and ultramicrotomy. A combination of high resolution TEM imaging and electron diffraction is used to characterize the opaque assemblages. The opaque assemblages analyzed in this study are dominated by ilmenite with lesser rutile and spinel exsolutions, and traces of Fe metal.

  10. An ASIC implementation of digital front-end electronics for a high resolution PET scanner

    International Nuclear Information System (INIS)

    Newport, D.F.; Young, J.W.

    1993-01-01

    AN Application Specific Integrated Circuit (ASIC) has been designed and fabricated which implements many of the current functions found in the digital front-end electronics for a high resolution Positron Emission Tomography (PET) scanner. The ASIC performs crystal selection, energy qualification, time correction, and event counting functions for block technology high resolution PET scanners. Digitized x and y position, event energy, and time information are used by the ASIC to determine block crystal number, qualify the event based on energy, and correct the event time. In addition, event counting and block dead time calculations are performed for system dead time corrections. A loadable sequencer for controlling the analog front-end electronics is also implemented. The ASIC is implemented in a 37,000 gate, 1.0 micron CMOS gate-array and is capable of handling 4 million events/second while reducing parts count, cost, and power consumption over current board-level designs

  11. Transmission electron microscopy of amyloid fibrils.

    Science.gov (United States)

    Gras, Sally L; Waddington, Lynne J; Goldie, Kenneth N

    2011-01-01

    Transmission Electron Microscopy of negatively stained and cryo-prepared specimens allows amyloid fibrils to be visualised at high resolution in a dried or a hydrated state, and is an essential method for characterising the morphology of fibrils and pre-fibrillar species. We outline the key steps involved in the preparation and observation of samples using negative staining and cryo-electron preservation. We also discuss methods to measure fibril characteristics, such as fibril width, from electron micrographs.

  12. High-resolution electron-beam patternable nanocomposite containing metal nanoparticles for plasmonics

    International Nuclear Information System (INIS)

    Abargues, R; Marques-Hueso, J; Canet-Ferrer, J; Pedrueza, E; Valdes, J L; Jimenez, E; MartInez-Pastor, J P

    2008-01-01

    Polymer nanocomposites containing noble metal nanoparticles are promising materials for plasmonic applications. In this paper, we report on a high-resolution negative-tone nanocomposite resist based on poly(vinyl alcohol) where silver nanoparticles and nanopatterns are simultaneously generated by electron-beam lithography. Our results indicate nanostructures with a relatively high concentration of nanoparticles and, consequently, an electromagnetic coupling among the nanoparticles. Therefore, the patternable nanocomposite described in this work may be a suitable material for future plasmonic circuitry

  13. Transmission and selection of macrolide resistant Mycoplasma genitalium infections detected by rapid high resolution melt analysis.

    Directory of Open Access Journals (Sweden)

    Jimmy Twin

    Full Text Available BACKGROUND: Mycoplasma genitalium (MG causes urethritis, cervicitis and pelvic inflammatory disease. The MG treatment failure rate using 1 g azithromycin at an Australian Sexual Health clinic in 2007-9 was 31% (95%CI 23-40%. We developed a rapid high resolution melt analysis (HRMA assay targeting resistance mutations in the MG 23S rRNA gene, and validated it against DNA sequencing by examining pre- and post-treatment archived samples from MG-infected patients. METHODOLOGY/PRINCIPAL FINDINGS: Available MG-positive pre-treatment (n = 82 and post-treatment samples from individuals with clinical treatment failure (n = 20 were screened for 23S rRNA gene mutations. Sixteen (20% pre-treatment samples possessed resistance mutations (A2058G, A2059G, A2059C, which were significantly more common in patients with symptomatic azithromycin-treatment failure (12/26; 44% than in those clinically cured (4/56; 7%, p<0.001. All 20 patients experiencing azithromycin-failure had detectable mutations in their post-treatment samples. In 9 of these cases, the same mutational types were present in both pre- and post-treatment samples indicating transmitted resistance, whilst in 11 of these cases (55%, mutations were absent in pre-treatment samples indicating likely selection of resistant isolates have occurred. HRMA was able to detect all mutational changes determined in this study by DNA sequencing. An additional HRMA assay incorporating an unlabelled probe was also developed to detect type 4 single-nucleotide polymorphisms found in other populations, with a slightly lower sensitivity of 90%. CONCLUSIONS/SIGNIFICANCE: Treatment failure is associated with the detection of macrolide resistance mutations, which appear to be almost equally due to selection of resistant isolates following exposure to 1 g azithromycin and pre-existing transmitted resistance. The application of a rapid molecular assay to detect resistance at the time of initial detection of infection allows

  14. Determination of the resonance parameters for 232Th from high resolution transmission and capture measurements at GELINA

    International Nuclear Information System (INIS)

    Brusegan, A.; Schillebeeckx, P.; Lobo, G.; Borella, A.; Volev, K.; Janeva, N.

    2003-01-01

    To deduce the resonance parameters for 232 Th in the resolved resonance region, high resolution transmission and capture measurements are being performed. The measurements are performed at the Time-Of-Flight facility GELINA. A comparison of experimental data resulting from capture (top) and transmission (bottom) are shown. The transmission measurements are performed at a 50 m flight path. The neutron are detected with a 0.25' thick lithium glass (NE912) placed in an Al sphere and viewed by a 5' EMI KQB photomultiplier orthogonal to the neutron beam axis. The injection of a stabilised light pulse in the detector during the measurements provided an efficient tool to control to better than 1% the gain of the entire electronics. The experimental set-up includes a sample-changer, placed at 23 m from the neutron source, which is driven by the acquisition system. The determination of the flight path length, was based on transmission of the 6.673 eV resonance of 238 U. We summarise, for the different energy regions of interest, the scheduled measurement conditions: the operation frequency of the accelerator and the target thickness. A simultaneous analysis of the data using REFIT will result in the resonance parameters from 0 to 4 keV. We show the result of a resonance shape analysis for the resonances at 21.8 and 23.5 eV. The resulting resonance parameters are important for the energy calibration and normalisation of the capture measurements in both the resolved and unresolved resonance region. The capture measurements are completed and were performed at a 60 m flight path. The sample consisted of a metallic natural thorium disc of 8 cm diameter and 1.0 mm thick, corresponding to a thickness of 3.176 10 -3 at/b. The neutron flux was measured with an ionisation chamber loaded with three back-to-back layers of about 40 μg/cm 2 10 B. The gamma rays, originating from the 232 Th(n,γ) reaction, were detected by four C 6 D 6 -based liquid scintillators (NE230) placed

  15. High resolution electron microscopy of a small crack at the superficial layer of enamel.

    Science.gov (United States)

    Hayashi, Y

    1994-12-01

    A small enamel crack was investigated using a high resolution electron microscope. The inside of the crack was filled with aggregates of irregularly oriented plate-like crystals. Amorphous mineral deposits were observed among these aggregates at a low magnification. Selected area electron diffractions indicated that the plate-like crystals consisted of hydroxyapatite (OH-AP), and that the amorphous mineral deposits were a mixture of OH-AP and whitlockite. These findings indicate that this crack may have been formed by occlusal and/or masticatory stress, and that a natural occlusion might occur through mineral deposition at the small crack such as in this case.

  16. Exploring semiconductor quantum dots and wires by high resolution electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Molina, S I [Departamento de Ciencia de los Materiales e Ing Metalurgica y Q. Inorganica, F. de Ciencias, Universidad de Cadiz, Campus Rio San Pedro. 11510 Puerto Real (Cadiz) (Spain); Galindo, P L [Departamento de Lenguajes y Sistemas Informaticos, CASEM, Universidad de Cadiz, Campus Rio San Pedro. 11510 Puerto Real (Cadiz) (Spain); Gonzalez, L; Ripalda, J M [Instituto de Microelectronica de Madrid (CNM, CSIC), Isaac Newton 8, 28760 Tres Cantos, Madrid (Spain); Varela, M; Pennycook, S J, E-mail: sergio.molina@uca.e [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge TN 37831 (United States)

    2010-02-01

    We review in this communication our contribution to the structural characterisation of semiconductor quantum dots and wires by high resolution electron microscopy, both in phase-contrast and Z-contrast modes. We show how these techniques contribute to predict the preferential sites of nucleation of these nanostructures, and also determine the compositional distribution in 1D and 0D nanostructures. The results presented here were produced in the framework of the European Network of Excellence entitled {sup S}elf-Assembled semiconductor Nanostructures for new Devices in photonics and Electronics (SANDiE){sup .}

  17. Carbon K-shell excitation in small molecules by high-resolution electron impact

    International Nuclear Information System (INIS)

    Tronc, M.; King, G.C.; Read, F.H.

    1979-01-01

    The excitation of 1s carbon electrons has been observed in C0, CH 4 , CF4, C0 2 , COS, C 2 H 2 and C 2 H 4 by means of the electron energy-loss technique with high resolution (70 meV in the 300 eV excitation energy range) and at an incident electron energy of 1.5 keV. The energies, widths and vibrational structures of excited states corresponding to the promotion of 1s carbon electrons to unoccupied valence and Rydberg orbitals have been obtained. The validity of the equivalent-core model, and the role of resonances caused by potential barriers, are discussed. (author)

  18. High-resolution compact Johann crystal spectrometer with the Livermore electron beam ion trap

    International Nuclear Information System (INIS)

    Robbins, D.L.; Chen, H.; Beiersdorfer, P.; Faenov, A.Ya.; Pikuz, T.A.; May, M.J.; Dunn, J.; Smith, A.J.

    2004-01-01

    A compact high-resolution (λ/Δλ≅10 000) spherically bent crystal spectrometer in the Johann geometry was recently installed and tested on the Lawrence Livermore National Laboratory SuperEBIT electron beam ion trap. The curvature of the mica (002) crystal grating allows for higher collection efficiency compared to the flat and cylindrically bent crystal spectrometers commonly used on the Livermore electron beam ion traps. The spectrometer's Johann configuration enables orientation of its dispersion plane to be parallel to the electron beam propagation. Used in concert with a crystal spectrometer, whose dispersion plane is perpendicular to the electron beam propagation, the polarization of x-ray emission lines can be measured

  19. Magnetic lens apparatus for a low-voltage high-resolution electron microscope

    Science.gov (United States)

    Crewe, Albert V.

    1996-01-01

    A lens apparatus in which a beam of charged particles of low accelerating voltage is brought to a focus by a magnetic field, the lens being situated behind the target position. The lens comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. The lens apparatus comprises the sole focusing lens for high-resolution imaging in a low-voltage scanning electron microscope.

  20. High resolution and high voltage electron microscopy at the University of California, Berkeley

    International Nuclear Information System (INIS)

    Thomas, G.; Westmacott, K.H.

    1978-01-01

    Recent applications of high-resolution and high-voltage techniques at Berkely are described, using 100-kV TEMs and a standard 650-keV HVEM: grain boundary precipitation in Al--Zn, lattice imaging of grain boundaries in ceramics, steels, phase transitions and magnetic properties of ferrites, lattice defects, precipitation in Al--Si and behavior of interstitial dislocations under electron irradiation, effect of oxide films on loop formation in Al--Mg, and polytypism in magnesium Sialon. 13 refs. 12 figs

  1. Applications of molecules as high-resolution, high-sensitivity threshold electron detectors

    International Nuclear Information System (INIS)

    Chutjian, A.

    1991-01-01

    The goal of the work under the contract entitled ''Applications of Molecules as High-Resolution, High-Sensitivity Threshold Electron Detectors'' (DoE IAA No. DE-AI01-83ER13093 Mod. A006) was to explore the electron attachment properties of a variety of molecules at electron energies not accessible by other experimental techniques. As a result of this work, not only was a large body of basic data measured on attachment cross sections and rate constants; but also extensive theoretical calculations were carried out to verify the underlying phenomenon of s-wave attachment. Important outgrowths of this week were also realized in other areas of research. The basic data have applications in fields such as combustion, soot reduction, rocket-exhaust modification, threshold photoelectron spectroscopy, and trace species detection

  2. Characterisation of phases in nanostructured, multilayered titanium alloys by analytical and high-resolution electron microscopy.

    Science.gov (United States)

    Czyrska-Filemonowicz, A; Buffat, P A

    2009-01-01

    Surface processing of a Ti-6Al-4V alloy led to a complex multilayered microstructure containing several phases of the Ni-Ti-P-Al-O system, which improves the mechanical and tribological surface properties. The microstructure, chemical and phase compositions of the hard layer formed on the surface were investigated by LM, XRD, SEM as well as analytical/high-resolution TEM, STEM, EDS, electron diffraction and FIB. Phase identification based on electron diffraction, HRTEM and EDS microanalysis revealed the presence of several binary and ternary phases in the system Ti-Ni-P, sometimes with partial substitution of Ti by Al. However some phases, mainly nanoparticles, still remain not identified satisfactorily. Electron microscopy techniques used for identification of phases present in surface multilayers and some practical limits to their routine application are reminded here.

  3. Development of a high-resolution electron-beam profile monitor using Fresnel zone plates

    International Nuclear Information System (INIS)

    Nakamura, Norio; Sakai, Hiroshi; Muto, Toshiya; Hayano, Hitoshi

    2004-01-01

    We present a high-resolution and real-time beam profile monitor using Fresnel zone plates (FZPs) developed in the KEK-ATF damping ring. The monitor system has an X-ray imaging optics with two FZPs. In this monitor, the synchrotron radiation from the electron beam at the bending magnet is monochromatized by a crystal monochromator and the transverse electron beam image is twenty-times magnified by the two FZPs and detected on an X-ray CCD camera. The expected spatial resolution for the selected photon energy of 3.235 keV is less than 1 μm. With the beam profile monitor, we succeeded in obtaining a clear electron-beam image and measuring the extremely small beam size less than 10 μm. It is greatly expected that the beam profile monitor will be used in high-brilliance light sources and low-emittance accelerators. (author)

  4. Electron beam fabrication and characterization of high- resolution magnetic force microscopy tips

    NARCIS (Netherlands)

    Ruhrig, M.; Rührig, M.; Porthun, S.; Porthun, S.; Lodder, J.C.; Mc vitie, S.; Heyderman, L.J.; Johnston, A.B.; Chapman, J.N.

    1996-01-01

    The stray field, magnetic microstructure, and switching behavior of high‐resolution electron beam fabricated thin film tips for magnetic force microscopy (MFM) are investigated with different imaging modes in a transmission electron microscope (TEM). As the tiny smooth carbon needles covered with a

  5. Ultrastable gold substrates: Properties of a support for high-resolution electron cryomicroscopy of biological specimens

    Science.gov (United States)

    Russo, Christopher J.; Passmore, Lori A.

    2016-01-01

    Electron cryomicroscopy (cryo-EM) allows structure determination of a wide range of biological molecules and specimens. All-gold supports improve cryo-EM images by reducing radiation-induced motion and image blurring. Here we compare the mechanical and electrical properties of all-gold supports to amorphous carbon foils. Gold supports are more conductive, and have suspended foils that are not compressed by differential contraction when cooled to liquid nitrogen temperatures. These measurements show how the choice of support material and geometry can reduce specimen movement by more than an order of magnitude during low-dose imaging. We provide methods for fabrication of all-gold supports and preparation of vitrified specimens. We also analyse illumination geometry for optimal collection of high resolution, low-dose data. Together, the support structures and methods herein can improve the resolution and quality of images from any electron cryomicroscope. PMID:26592474

  6. An extended model of electrons: experimental evidence from high-resolution scanning tunneling microscopy

    International Nuclear Information System (INIS)

    Hofer, Werner A

    2012-01-01

    In a recent paper we introduced a model of extended electrons, which is fully compatible with quantum mechanics in the formulation of Schrödinger. However, it contradicts the current interpretation of electrons as point-particles. Here, we show by a statistical analysis of high-resolution scanning tunneling microscopy (STM) experiments, that the interpretation of electrons as point particles and, consequently, the interpretation of the density of electron charge as a statistical quantity will lead to a conflict with the Heisenberg uncertainty principle. Given the precision in these experiments we find that the uncertainty principle would be violated by close to two orders of magnitude, if this interpretation were correct. We are thus forced to conclude that the density of electron charge is a physically real, i.e. in principle precisely measurable quantity, as derived in a recent paper. Experimental evidence to the contrary, in particular high-energy scattering experiments, is briefly discussed. The finding is expected to have wide implications in condensed matter physics, chemistry, and biology, scientific disciplines which are based on the properties and interactions of electrons.

  7. THE HIGH-RESOLUTION EXTREME-ULTRAVIOLET SPECTRUM OF N{sub 2} BY ELECTRON IMPACT

    Energy Technology Data Exchange (ETDEWEB)

    Heays, A. N. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Ajello, J. M.; Aguilar, A. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Lewis, B. R.; Gibson, S. T., E-mail: heays@strw.leidenuniv.nl [Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia)

    2014-04-01

    We have analyzed high-resolution (FWHM = 0.2 Å) extreme-ultraviolet (EUV, 800-1350 Å) laboratory emission spectra of molecular nitrogen excited by an electron impact at 20 and 100 eV under (mostly) optically thin, single-scattering experimental conditions. A total of 491 emission features were observed from N{sub 2} electronic-vibrational transitions and atomic N I and N II multiplets and their emission cross sections were measured. Molecular emission was observed at vibrationally excited ground-state levels as high as v'' = 17, from the a {sup 1}Π {sub g} , b {sup 1}Π {sub u} , and b'{sup 1}Σ {sub u} {sup +} excited valence states and the Rydberg series c'{sub n} {sub +1} {sup 1}Σ {sub u} {sup +}, c{sub n} {sup 1}Π {sub u} , and o{sub n} {sup 1}Π {sub u} for n between 3 and 9. The frequently blended molecular emission bands were disentangled with the aid of a sophisticated and predictive quantum-mechanical model of excited states that includes the strong coupling between valence and Rydberg electronic states and the effects of predissociation. Improved model parameters describing electronic transition moments were obtained from the experiment and allowed for a reliable prediction of the vibrationally summed electronic emission cross section, including an extrapolation to unobserved emission bands and those that are optically thick in the experimental spectra. Vibrationally dependent electronic excitation functions were inferred from a comparison of emission features following 20 and 100 eV electron-impact collisional excitation. The electron-impact-induced fluorescence measurements are compared with Cassini Ultraviolet Imaging Spectrograph observations of emissions from Titan's upper atmosphere.

  8. High resolution electron backscatter diffraction (EBSD) data from calcite biominerals in recent gastropod shells.

    Science.gov (United States)

    Pérez-Huerta, Alberto; Dauphin, Yannicke; Cuif, Jean Pierre; Cusack, Maggie

    2011-04-01

    Electron backscatter diffraction (EBSD) is a microscopy technique that reveals in situ crystallographic information. Currently, it is widely used for the characterization of geological materials and in studies of biomineralization. Here, we analyze high resolution EBSD data from biogenic calcite in two mollusk taxa, Concholepas and Haliotis, previously used in the understanding of complex biomineralization and paleoenvironmental studies. Results indicate that Concholepas has less ordered prisms than in Haliotis, and that in Concholepas the level of order is not homogenous in different areas of the shell. Overall, the usefulness of data integration obtained from diffraction intensity and crystallographic orientation maps, and corresponding pole figures, is discussed as well as its application to similar studies. © 2010 Elsevier Ltd. All rights reserved.

  9. Structure and chemistry of epitaxial ceria thin films on yttria-stabilized zirconia substrates, studied by high resolution electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sinclair, Robert, E-mail: bobsinc@stanford.edu [Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305 (United States); Lee, Sang Chul, E-mail: sclee99@stanford.edu [Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305 (United States); Shi, Yezhou; Chueh, William C. [Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305 (United States); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States)

    2017-05-15

    We have applied aberration-corrected transmission electron microscopy (TEM) imaging and electron energy loss spectroscopy (EELS) to study the structure and chemistry of epitaxial ceria thin films, grown by pulsed laser deposition onto (001) yttria-stabilized zirconia (YSZ) substrates. There are few observable defects apart from the expected mismatch interfacial dislocations and so the films would be expected to have good potential for applications. Under high electron beam dose rate (above about 6000 e{sup -}/Å{sup 2}s) domains of an ordered structure appear and these are interpreted as being created by oxygen vacancy ordering. The ordered structure does not appear at lower lose rates (ca. 2600 e{sup -}/Å{sup 2}s) and can be removed by imaging under 1 mbar oxygen gas in an environmental TEM. EELS confirms that there is both oxygen deficiency and the associated increase in Ce{sup 3+} versus Ce{sup 4+} cations in the ordered domains. In situ high resolution TEM recordings show the formation of the ordered domains as well as atomic migration along the ceria thin film (001) surface. - Highlights: • The local structure and chemistry of ceria can be studied by TEM combined with EELS. • At lower electron, there are no observable changes in the ceria thin films. • At higher dose rates, an ordered phase is created due to oxygen vacancy ordering. • In situ HRTEM shows the oxygen vacancy ordering and the movement of surface atoms.

  10. Minimal exposure technique in the Cambridge University 600kV high resolution electron microscope

    International Nuclear Information System (INIS)

    Fryer, J.R.; Cleaver, J.R.A.; Smith, D.J.

    1980-01-01

    Radiation damage due to the incident electron beam imposes a fundamental limitation on the information obtainable by electron microscopy about organic materials; it is desirable therefore that exposure of the specimen to the electron beam should be restricted to the actual period during which the image is being recorded. A description is given of methods employed in the observation of the organic aromatic hydrocarbons quaterrylene, ovalene and coronene with the Cambridge University 600kV high resolution electron microscope (HREM). In particular, the condenser-objective mode of operation of this microscope lends itself to the use of an area-defining aperture below the second condenser lens conjugate with the specimen. Furthermore, operation at the higher accelerating voltage of this instrument could be anticipated to reduce the rate of damage, depending on the dominant beam-specimen interaction, whilst the increased width of the first broad band of the contrast transfer function of this microscope at the optimum defocus may overcome the reported resolution limitation of current 100kV microscopes for the observation of related materials. (author)

  11. Ponderomotive phase plate for transmission electron microscopes

    Science.gov (United States)

    Reed, Bryan W [Livermore, CA

    2012-07-10

    A ponderomotive phase plate system and method for controllably producing highly tunable phase contrast transfer functions in a transmission electron microscope (TEM) for high resolution and biological phase contrast imaging. The system and method includes a laser source and a beam transport system to produce a focused laser crossover as a phase plate, so that a ponderomotive potential of the focused laser crossover produces a scattering-angle-dependent phase shift in the electrons of the post-sample electron beam corresponding to a desired phase contrast transfer function.

  12. High resolution surface scanning of Thick-GEM for single photo-electron detection

    International Nuclear Information System (INIS)

    Hamar, G.; Varga, D.

    2012-01-01

    An optical system for high resolution scanning of TGEM UV photon detection systems is introduced. The structure exploits the combination of a single Au-coated TGEM under study, and an asymmetric MWPC (Close Cathode Chamber) as post-amplification stage. A pulsed UV LED source with emission down to 240 nm has been focused to a spot of 0.07 mm on the TGEM surface, and single photo-electron charge spectra has been recorded over selected two dimensional regions. This way, the TGEM gain (order of 10–100) and TGEM photo-electron detection efficiency is clearly separated, unlike in case of continuous illumination. The surface structure connected to the TGEM photon detection is well observable, including inefficiencies in the holes and at the symmetry points between holes. The detection efficiency as well as the gas gain are fluctuating from hole to hole. The gain is constant in the hexagon around any hole, pointing to the fact that the gain depends on hole geometry, and less on the position where the electron enters. The detection probability map strongly changes with the field strength above the TGEM surface, in relation to the change of the actual surface field configuration. The results can be confronted with position-dependent simulations of TGEM electron transfer and gas multiplication. -- Highlights: ► First demonstration of Thick GEM surface scanning with single photo-electrons. ► Resolution of 0.1 mm is sufficient to identify structures connected to TGEM surface field structure. ► Gain and detection efficiency and separately measurable. ► Detection efficiency is high in a ring around the holes, and gain is constant in the hexagonal collection regions.

  13. High resolution surface scanning of Thick-GEM for single photo-electron detection

    Energy Technology Data Exchange (ETDEWEB)

    Hamar, G., E-mail: hamar.gergo@wigner.mta.hu [Wigner Research Centre for Physics, Budapest (Hungary); Varga, D., E-mail: vdezso@mail.cern.ch [Eoetvoes Lorand University, Budapest (Hungary)

    2012-12-01

    An optical system for high resolution scanning of TGEM UV photon detection systems is introduced. The structure exploits the combination of a single Au-coated TGEM under study, and an asymmetric MWPC (Close Cathode Chamber) as post-amplification stage. A pulsed UV LED source with emission down to 240 nm has been focused to a spot of 0.07 mm on the TGEM surface, and single photo-electron charge spectra has been recorded over selected two dimensional regions. This way, the TGEM gain (order of 10-100) and TGEM photo-electron detection efficiency is clearly separated, unlike in case of continuous illumination. The surface structure connected to the TGEM photon detection is well observable, including inefficiencies in the holes and at the symmetry points between holes. The detection efficiency as well as the gas gain are fluctuating from hole to hole. The gain is constant in the hexagon around any hole, pointing to the fact that the gain depends on hole geometry, and less on the position where the electron enters. The detection probability map strongly changes with the field strength above the TGEM surface, in relation to the change of the actual surface field configuration. The results can be confronted with position-dependent simulations of TGEM electron transfer and gas multiplication. -- Highlights: Black-Right-Pointing-Pointer First demonstration of Thick GEM surface scanning with single photo-electrons. Black-Right-Pointing-Pointer Resolution of 0.1 mm is sufficient to identify structures connected to TGEM surface field structure. Black-Right-Pointing-Pointer Gain and detection efficiency and separately measurable. Black-Right-Pointing-Pointer Detection efficiency is high in a ring around the holes, and gain is constant in the hexagonal collection regions.

  14. Through-the-wall high-resolution imaging of a human and experimental characterization of the transmission of wall materials

    Science.gov (United States)

    Nilsson, S.; Jänis, A.; Gustafsson, M.; Kjellgren, J.; Sume, Ain

    2008-10-01

    This paper describes the research efforts made at the Swedish Defence Research Agency (FOI) concerning through-the-wall imaging radar, as well as fundamental characterization of various wall materials. These activities are a part of two FOI-projects concerning security sensors in the aspects of Military Operations in Urban Terrain (MOUT) and Homeland Defence. Through-the-wall high resolution imaging of a human between 28-40 GHz has been performed at FOI. The UWB radar that was used is normally a member of the instrumentation of the FOI outdoor RCS test range Lilla Gåra. The armed test person was standing behind different kinds of walls. The radar images were generated by stepping the turntable in azimuth and elevation. The angular resolution in the near-field was improved by refocusing the parabolic antennas, which in combination with the large bandwidth (12 GHz) gave extremely high resolution radar images. A 3D visualization of the person even exposed the handgun tucked into one hip pocket. A qualitative comparison between the experimental results and simulation results (physical optics-based method) will also be presented. The second part of this paper describes results from activities at FOI concerning material characterization in the 2-110 GHz region. The transmission of building, packing and clothing materials has been experimentally determined. The wide-band measurements in free space were carried out with a scalar network analyzer. In this paper results from these characterizations will be presented. Furthermore, an experimental investigation will be reported of how the transmission properties for some moisted materials change as a function of water content and frequency. We will also show experimental results of how the transmission properties of a pine panel are affected when the surface is coated with a thin surface layer of water.

  15. High resolution electron microscope study of the omega transformation in Zr--Nb alloys

    International Nuclear Information System (INIS)

    Chang, A.L.J.; Sass, S.L.; Krakow, W.

    1976-01-01

    High resolution direct lattice imaging and dark field electron microscopy were used to examine the omega phase transformation in Zr--Nb alloys. Direct lattice imaging demonstrated the existence of subvariants within an omega variant. The existence of an ordered sequence of subvariants, which is the basic premise of recent diffuse intensity calculations which seek to explain diffuse diffraction observations in high Nb content alloys, could not be checked because of the small size of the omega regions. In the low Nb content alloys dark field electron microscopy was used to show that the ω phase consists of large domains (100 to 200 A dia) the interior of which contains features that are 3 to 6 A dia. As the Nb content is increased the omega domains decrease in size until only 3 to 5 A images are observed in alloys containing 15 wt. percent Nb or more. The isolated images are present over the range of composition from 8 to 30 wt. percent Nb. Time sequence dark field micrographs show that these small images change with time. The diffuse ω reflections are believed due in part to the existence of a (111) linear detect, consisting of groups of (111) rows of atoms which are displaced from bcc to ω positions for short periods of time

  16. High resolution beam profiling of X-ray free electron laser radiation by polymer imprint development.

    Science.gov (United States)

    Rösner, Benedikt; Döring, Florian; Ribič, Primož R; Gauthier, David; Principi, Emiliano; Masciovecchio, Claudio; Zangrando, Marco; Vila-Comamala, Joan; De Ninno, Giovanni; David, Christian

    2017-11-27

    High resolution metrology of beam profiles is presently a major challenge at X-ray free electron lasers. We demonstrate a characterization method based on beam imprints in poly (methyl methacrylate). By immersing the imprints formed at 47.8 eV into organic solvents, the regions exposed to the beam are removed similar to resist development in grayscale lithography. This allows for extending the sensitivity of the method by more than an order of magnitude compared to the established analysis of imprints created solely by ablation. Applying the Beer-Lambert law for absorption, the intensity distribution in a micron-sized focus can be reconstructed from one single shot with a high dynamic range, exceeding 10 3 . The procedure described here allows for beam characterization at free electron lasers revealing even faint beam tails, which are not accessible when using ablation imprint methods. We demonstrate the greatly extended dynamic range on developed imprints taken in focus of conventional Fresnel zone plates and spiral zone plates producing beams with a topological charge.

  17. High-resolution x-ray scattering studies of charge ordering in highly correlated electron systems

    International Nuclear Information System (INIS)

    Ghazi, M.E.

    2002-01-01

    Many important properties of transition metal oxides such as, copper oxide high-temperature superconductivity and colossal magnetoresistance (CMR) in manganites are due to strong electron-electron interactions, and hence these systems are called highly correlated systems. These materials are characterised by the coexistence of different kinds of order, including charge, orbital, and magnetic moment. This thesis contains high-resolution X-ray scattering studies of charge ordering in such systems namely the high-T C copper oxides isostructural system, La 2-x Sr x NiO 4 with various Sr concentrations (x = 0.33 - 0.2), and the CMR manganite system, Nd 1/2 Sr 1/2 MnO 3 . It also includes a review of charge ordering in a large variety of transition metal oxides, such as ferrates, vanadates, cobaltates, nickelates, manganites, and cuprates systems, which have been reported to date in the scientific literature. Using high-resolution synchrotron X-ray scattering, it has been demonstrated that the charge stripes exist in a series of single crystals of La 2-x Sr x NiO 4 with Sr concentrations (x = 0.33 - 0.2) at low temperatures. Satellite reflections due to the charge ordering were found with the wavevector (2ε, 0, 1) below the charge ordering transition temperature, T CO , where 2ε is the amount of separation from the corresponding Bragg peak. The charge stripes are shown to be two-dimensional in nature both by measurements of their correlation lengths and by measurement of the critical exponents of the charge stripe melting transition with an anomaly at x = 0.25. The results show by decreasing the hole concentration from the x = 0.33 to 0.2, the well-correlated charge stripes change to a glassy state at x = 0.25. The electronic transition into the charge stripe phase is second-order without any corresponding structural transition. Above the second-order transition critical scattering was observed due to fluctuations into the charge stripe phase. In a single-crystal of Nd

  18. Monochromated scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Rechberger, W.; Kothleitner, G.; Hofer, F.

    2006-01-01

    Full text: Electron energy-loss spectroscopy (EELS) has developed into an established technique for chemical and structural analysis of thin specimens in the (scanning) transmission electron microscope (S)TEM. The energy resolution in EELS is largely limited by the stability of the high voltage supply, by the resolution of the spectrometer and by the energy spread of the source. To overcome this limitation a Wien filter monochromator was recently introduced with commercially available STEMs, offering the advantage to better resolve EELS fine structures, which contain valuable bonding information. The method of atomic resolution Z-contrast imaging within an STEM, utilizing a high-angle annular dark-field (HAADF) detector can perfectly complement the excellent energy resolution, since EELS spectra can be collected simultaneously. In combination with a monochromator microscope not only high spatial resolution images can be recorded but also high energy resolution EELS spectra are attainable. In this work we investigated the STEM performance of a 200 kV monochromated Tecnai F20 with a high resolution Gatan Imaging Filter (HR-GIF). (author)

  19. Structural investigation of the amorphous/crystalline interface by means of quantitative high-resolution transmission electron microscopy on the systems a-Si/c-Si and a-Ge/c-Si; Strukturelle Untersuchung der amorph/kristallinen Grenzflaeche mittels quantitativer hochaufloesender Transmissionselektronenmikroskopie an den Systemen a-Si/c-Si und a-Ge/c-Si

    Energy Technology Data Exchange (ETDEWEB)

    Thiel, K.

    2006-11-02

    In this Thesis the interfaces between covalently bonded crystalline and amorphous materials were studied with regard to the induced ordering in the amorphous material in the interfacial region by means of high-resolution transmission electron microscopy (HREM). The interface between amorphous germanium and crystalline silicon and the interface between amorphous and crystalline silicon served as material system. In order to quantify the influence of the crystalline order on the amorphous material, the HREM images were periodically averaged along the interface. The intensity components, which are correlated with the period of the lattice image, could thus be separated from the statistical intensity fluctuations, which are characteristic for images of amorphous materials. Since amorphous materials can only be described meaningful by statistical distribution functions, for the induced order a three-dimensional distribution function {rho}{sub 3D}(r) was taken as a basis, which describes the probability to find an atom in the amorphous material, if r=0 is the position of an atom in the crystal. Its two-dimensional projection, {rho}, can be determined using iterative image matching techniques on averaged experimental and simulated interface images. For the analyzed material systems {rho} exhibits lateral ordering as well as a pronounced layering in the vicinity of the interface. In the case of the a-Si/c-Si sample the mean orientation of bonds was 70.5 , as is in the case of the undistorted diamond lattice, while for the a-Ge/c-Si sample 65 resulted. The standard deviation for the distribution of the deviations from the mean bond angle yields for the a-Ge/c-Si sample in the first atomic layer a value of 11.3 and for the a-Si/c-Si sample 1.9 . These results suggest the conclusion, that the differences in these values are to be interpreted as the reaction of the amorphous material to the volume misfit. Although for both material systems 1.4 nm was calculated for the width

  20. High-resolution electron microscopic evidence for the filamentous structure of the cyst wall in Giardia muris and Giardia duodenalis.

    Science.gov (United States)

    Erlandsen, S L; Bemrick, W J; Pawley, J

    1989-10-01

    High-resolution morphological studies of the cyst wall of Giardia spp. were performed using low-voltage scanning electron microscopy (LVSEM) and transmission electron microscopy (TEM). The cyst wall was composed of membranous and filamentous layers. The membranous layer consisted of an inner and an outer cyst membrane separated by a thin layer of cytoplasm. The filamentous layer contained individual filaments that ranged from 7 to 20 nm in diameter when measured by LVSEM, formed a dense meshwork with branches or interconnections, and were occasionally arranged on the surface in whorled patterns. Cysts of Giardia muris from mice, Giardia duodenalis from dogs, pigs, voles, beavers, muskrats, and humans, and Giardia psittaci from a bird (parakeet), possessed an essentially identical wall composed of filaments. Inducement of excystation in viable Giardia cysts produced a dramatic increase in the interfilament spacing over an entire cyst, but none was observed in heat-killed or chemically fixed control cysts. These results demonstrated that the cyst wall of Giardia spp. was composed of a complex arrangement of filaments, presumably formed during the process of encystment.

  1. Calibration of high-resolution electronic autocollimators with demanded low uncertainties using single reading head angle encoders

    International Nuclear Information System (INIS)

    Yandayan, Tanfer; Akgoz, S Asli; Asar, Muharrem

    2014-01-01

    Calibration of high-resolution electronic autocollimators is carried out in TUBITAK UME using an angle comparator to ensure direct traceability to the SI unit of plane angle, radian (rad). The device is a specially designed air-bearing rotary table fitted with a commercially available angular encoder utilizing a single reading head. It is shown that high-resolution electronic autocollimators in the large measurement range (e.g. ±1000 arcsec) can be calibrated with an expanded uncertainty of 0.035 arcsec (k = 2) in conventional dimensional laboratory conditions, applying good measurement strategy for single reading head angle encoders and taking simple but smart precautions. Description of the angle comparator is presented with various test results derived using different high-precision autocollimators, and a detailed uncertainty budget is given for the calibration of a high-resolution electronic autocollimator. (paper)

  2. The effect of pattern overlap on the accuracy of high resolution electron backscatter diffraction measurements

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Vivian, E-mail: v.tong13@imperial.ac.uk [Department of Materials, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom); Jiang, Jun [Department of Materials, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom); Wilkinson, Angus J. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Britton, T. Ben [Department of Materials, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom)

    2015-08-15

    High resolution, cross-correlation-based, electron backscatter diffraction (EBSD) measures the variation of elastic strains and lattice rotations from a reference state. Regions near grain boundaries are often of interest but overlap of patterns from the two grains could reduce accuracy of the cross-correlation analysis. To explore this concern, patterns from the interior of two grains have been mixed to simulate the interaction volume crossing a grain boundary so that the effect on the accuracy of the cross correlation results can be tested. It was found that the accuracy of HR-EBSD strain measurements performed in a FEG-SEM on zirconium remains good until the incident beam is less than 18 nm from a grain boundary. A simulated microstructure was used to measure how often pattern overlap occurs at any given EBSD step size, and a simple relation was found linking the probability of overlap with step size. - Highlights: • Pattern overlap occurs at grain boundaries and reduces HR-EBSD accuracy. • A test is devised to measure the accuracy of HR-EBSD in the presence of overlap. • High pass filters can sometimes, but not generally, improve HR-EBSD measurements. • Accuracy of HR-EBSD remains high until the reference pattern intensity is <72%. • 9% of points near a grain boundary will have significant error for 200nm step size in Zircaloy-4.

  3. Micaceous occlusions in kaolinite observed by ultramicrotomy and high resolution electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S Y [Univ. of Wisconsin, Madison; Jackson, M L; Brown, J L

    1975-01-01

    The layer structure of kaolinite from Twiggs, Georgia, and fire-clay type kaolinite (Frantex B, from France, particle size separates 2 0.2 ..mu..m was studied by high resolution electron microscopy after embedment in Spurr low-viscosity Epoxy media and thin sectioning normal to the (001) planes by an ultramicrotome. Images of the (001) planes (viewed edge-on) of both kaolinites were spaced at 7 A and generally aligned in parallel, with occasional bending into more widely spaced images of about 10 A interval. Some of the 10 A images converged to 7 A at one or both ends, forming ellipse-shaped islands 80 to 130 A thick and 300 to 500 A long. The island areas and interleaved 10 A layers between 7 A layers may represent a residue of incomplete weathering of mica to kaolinite. The proportions of micaceous occlusions were too small and the layer sequences too irregular to be detected by X-ray diffraction. The lateral continuity of the layers through the 7-10-7 A sequence in a kaolinite particle would partially interrupt or prevent expansion in dimethyl sulfoxide (DMSO) and other kaolinite intercalating media. Discrete mica particles were also observed with parallel images at 10 A, as impurities in both kaolinites. The small K content of the chemical analyses of the kaolinite samples is accounted for as interlayer K, not only in discrete mica particles but also in the micaceous occlusions.

  4. A high resolution electron microscopy investigation of curvature in carbon nanotubes

    Science.gov (United States)

    Weldon, D. N.; Blau, W. J.; Zandbergen, H. W.

    1995-07-01

    Evidence for heptagon inclusion in multi-walled carbon nanotubes was sought in arc-produced carbon deposits. Transmission electron microscopy revealed many curved nanotubes although their relative abundance was low. Close examination of the micrographs in the regions of expected heptagon inclusion shows that the curvature is accomplished by folding or fracture of the lattice planes. This observed phenomenon contradicts the theoretical modelling studies which predict stable structures with negative curvature accomplished by heptagon/pentagon pairs. A possible explanation for curvature in single-walled tubes is presented based on a molecular mechanics geometry optimisation study of spa inclusion in a graphite sheet.

  5. Direct observations of the MOF (UiO-66) structure by transmission electron microscopy

    KAUST Repository

    Zhu, Liangkui; Zhang, Daliang; Xue, Ming; Li, Huan; Qiu, Shilun

    2013-01-01

    As a demonstration of ab initio structure characterizations of nano metal organic framework (MOF) crystals by high resolution transmission electron microscopy (HRTEM) and electron diffraction tomography methods, a Zr-MOF (UiO-66) structure

  6. Fluorescence photooxidation with eosin: a method for high resolution immunolocalization and in situ hybridization detection for light and electron microscopy

    Science.gov (United States)

    1994-01-01

    A simple method is described for high-resolution light and electron microscopic immunolocalization of proteins in cells and tissues by immunofluorescence and subsequent photooxidation of diaminobenzidine tetrahydrochloride into an insoluble osmiophilic polymer. By using eosin as the fluorescent marker, a substantial improvement in sensitivity is achieved in the photooxidation process over other conventional fluorescent compounds. The technique allows for precise correlative immunolocalization studies on the same sample using fluorescence, transmitted light and electron microscopy. Furthermore, because eosin is smaller in size than other conventional markers, this method results in improved penetration of labeling reagents compared to gold or enzyme based procedures. The improved penetration allows for three-dimensional immunolocalization using high voltage electron microscopy. Fluorescence photooxidation can also be used for high resolution light and electron microscopic localization of specific nucleic acid sequences by in situ hybridization utilizing biotinylated probes followed by an eosin-streptavidin conjugate. PMID:7519623

  7. Novel method of simultaneous multiple immunogold localization on resin sections in high resolution scanning electron microscopy

    Czech Academy of Sciences Publication Activity Database

    Nebesářová, Jana; Wandrol, P.; Vancová, Marie

    2016-01-01

    Roč. 12, č. 1 (2016), s. 105-517 ISSN 1549-9634 R&D Projects: GA TA ČR(CZ) TE01020118 Institutional support: RVO:60077344 Keywords : multiple immunolabeling * gold nanoparticles * high resolution SEM * STEM imaging * BSE imaging Subject RIV: EA - Cell Biology Impact factor: 5.720, year: 2016

  8. Dense sampled transmission matrix for high resolution angular spectrum imaging through turbid media via compressed sensing (Conference Presentation)

    Science.gov (United States)

    Jang, Hwanchol; Yoon, Changhyeong; Choi, Wonshik; Eom, Tae Joong; Lee, Heung-No

    2016-03-01

    We provide an approach to improve the quality of image reconstruction in wide-field imaging through turbid media (WITM). In WITM, a calibration stage which measures the transmission matrix (TM), the set of responses of turbid medium to a set of plane waves with different incident angles, is preceded to the image recovery. Then, the TM is used for estimation of object image in image recovery stage. In this work, we aim to estimate highly resolved angular spectrum and use it for high quality image reconstruction. To this end, we propose to perform a dense sampling for TM measurement in calibration stage with finer incident angle spacing. In conventional approaches, incident angle spacing is made to be large enough so that the columns in TM are out of memory effect of turbid media. Otherwise, the columns in TM are correlated and the inversion becomes difficult. We employ compressed sensing (CS) for a successful high resolution angular spectrum recovery with dense sampled TM. CS is a relatively new information acquisition and reconstruction framework and has shown to provide superb performance in ill-conditioned inverse problems. We observe that the image quality metrics such as contrast-to-noise ratio and mean squared error are improved and the perceptual image quality is improved with reduced speckle noise in the reconstructed image. This results shows that the WITM performance can be improved only by executing dense sampling in the calibration stage and with an efficient signal reconstruction framework without elaborating the overall optical imaging systems.

  9. Segmentation methodology for automated classification and differentiation of soft tissues in multiband images of high-resolution ultrasonic transmission tomography.

    Science.gov (United States)

    Jeong, Jeong-Won; Shin, Dae C; Do, Synho; Marmarelis, Vasilis Z

    2006-08-01

    This paper presents a novel segmentation methodology for automated classification and differentiation of soft tissues using multiband data obtained with the newly developed system of high-resolution ultrasonic transmission tomography (HUTT) for imaging biological organs. This methodology extends and combines two existing approaches: the L-level set active contour (AC) segmentation approach and the agglomerative hierarchical kappa-means approach for unsupervised clustering (UC). To prevent the trapping of the current iterative minimization AC algorithm in a local minimum, we introduce a multiresolution approach that applies the level set functions at successively increasing resolutions of the image data. The resulting AC clusters are subsequently rearranged by the UC algorithm that seeks the optimal set of clusters yielding the minimum within-cluster distances in the feature space. The presented results from Monte Carlo simulations and experimental animal-tissue data demonstrate that the proposed methodology outperforms other existing methods without depending on heuristic parameters and provides a reliable means for soft tissue differentiation in HUTT images.

  10. Coma-free alignment of high resolution electron microscopes with the aid of optical diffractograms

    International Nuclear Information System (INIS)

    Zemlin, F.; Weiss, K.; Schiske, P.; Kunath, W.; Herrmann, K.-H.

    1978-01-01

    Alignment by means of current commutating and defocusing of the objective does not yield the desired rotational symmetry of the imaging pencils. This was found while aligning a transmission electron microscope with a single field condenser objective. A series of optical diffractograms of micrographs taken under the same tilted illumination yet under various azimuths have been arranged in a tableau, wherein strong asymmetry is exhibited. Quantitative evaluation yields the most important asymmetric aberration to be the axial coma, which becomes critical when a resolution better than 5 A 0 is obtained. The tableau also allows an assessment of the three-fold astigmatism. A procedure has been developed which aligns the microscope onto the coma-free and dispersion-free pencil axis and does not rely on current communication. The procedure demands equal appearance of astigmatic carbon film images produced under the same tilt yet diametrical azimuth. (Auth.)

  11. Bio-camouflage of anatase nanoparticles explored by in situ high-resolution electron microscopy.

    Science.gov (United States)

    Ribeiro, Ana R; Mukherjee, Arijita; Hu, Xuan; Shafien, Shayan; Ghodsi, Reza; He, Kun; Gemini-Piperni, Sara; Wang, Canhui; Klie, Robert F; Shokuhfar, Tolou; Shahbazian-Yassar, Reza; Borojevic, Radovan; Rocha, Luis A; Granjeiro, José M

    2017-08-03

    While titanium is the metal of choice for most prosthetics and inner body devices due to its superior biocompatibility, the discovery of Ti-containing species in the adjacent tissue as a result of wear and corrosion has been associated with autoimmune diseases and premature implant failures. Here, we utilize the in situ liquid cell transmission electron microscopy (TEM) in a liquid flow holder and graphene liquid cells (GLCs) to investigate, for the first time, the in situ nano-bio interactions between titanium dioxide nanoparticles and biological medium. This imaging and spectroscopy methodology showed the process of formation of an ionic and proteic bio-camouflage surrounding Ti dioxide (anatase) nanoparticles that facilitates their internalization by bone cells. The in situ understanding of the mechanisms of the formation of the bio-camouflage of anatase nanoparticles may contribute to the definition of strategies aimed at the manipulation of these NPs for bone regenerative purposes.

  12. High-resolution monochromated electron energy-loss spectroscopy of organic photovoltaic materials.

    Science.gov (United States)

    Alexander, Jessica A; Scheltens, Frank J; Drummy, Lawrence F; Durstock, Michael F; Hage, Fredrik S; Ramasse, Quentin M; McComb, David W

    2017-09-01

    Advances in electron monochromator technology are providing opportunities for high energy resolution (10 - 200meV) electron energy-loss spectroscopy (EELS) to be performed in the scanning transmission electron microscope (STEM). The energy-loss near-edge structure in core-loss spectroscopy is often limited by core-hole lifetimes rather than the energy spread of the incident illumination. However, in the valence-loss region, the reduced width of the zero loss peak makes it possible to resolve clearly and unambiguously spectral features at very low energy-losses (photovoltaics (OPVs): poly(3-hexlythiophene) (P3HT), [6,6] phenyl-C 61 butyric acid methyl ester (PCBM), copper phthalocyanine (CuPc), and fullerene (C 60 ). Data was collected on two different monochromated instruments - a Nion UltraSTEM 100 MC 'HERMES' and a FEI Titan 3 60-300 Image-Corrected S/TEM - using energy resolutions (as defined by the zero loss peak full-width at half-maximum) of 35meV and 175meV, respectively. The data was acquired to allow deconvolution of plural scattering, and Kramers-Kronig analysis was utilized to extract the complex dielectric functions. The real and imaginary parts of the complex dielectric functions obtained from the two instruments were compared to evaluate if the enhanced resolution in the Nion provides new opto-electronic information for these organic materials. The differences between the spectra are discussed, and the implications for STEM-EELS studies of advanced materials are considered. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Neuroanatomy from Mesoscopic to Nanoscopic Scales: An Improved Method for the Observation of Semithin Sections by High-Resolution Scanning Electron Microscopy.

    Science.gov (United States)

    Rodríguez, José-Rodrigo; Turégano-López, Marta; DeFelipe, Javier; Merchán-Pérez, Angel

    2018-01-01

    Semithin sections are commonly used to examine large areas of tissue with an optical microscope, in order to locate and trim the regions that will later be studied with the electron microscope. Ideally, the observation of semithin sections would be from mesoscopic to nanoscopic scales directly, instead of using light microscopy and then electron microscopy (EM). Here we propose a method that makes it possible to obtain high-resolution scanning EM images of large areas of the brain in the millimeter to nanometer range. Since our method is compatible with light microscopy, it is also feasible to generate hybrid light and electron microscopic maps. Additionally, the same tissue blocks that have been used to obtain semithin sections can later be used, if necessary, for transmission EM, or for focused ion beam milling and scanning electron microscopy (FIB-SEM).

  14. High-resolution electron microscope image analysis approach for superconductor YBa2Cu3O7-x

    International Nuclear Information System (INIS)

    Xu, J.; Lu, F.; Jia, C.; Hua, Z.

    1991-01-01

    In this paper, an HREM (High-resolution electron microscope) image analysis approach has been developed. The image filtering, segmentation and particles extraction based on gray-scale mathematical morphological operations, are performed on the original HREM image. The final image is a pseudocolor image, with the background removed, relatively uniform brightness, filtered slanting elongation, regular shape for every kind of particle, and particle boundaries that no longer touch each other so that the superconducting material structure can be shown clearly

  15. High-resolution patterning of graphene by screen printing with a silicon stencil for highly flexible printed electronics.

    Science.gov (United States)

    Hyun, Woo Jin; Secor, Ethan B; Hersam, Mark C; Frisbie, C Daniel; Francis, Lorraine F

    2015-01-07

    High-resolution screen printing of pristine graphene is introduced for the rapid fabrication of conductive lines on flexible substrates. Well-defined silicon stencils and viscosity-controlled inks facilitate the preparation of high-quality graphene patterns as narrow as 40 μm. This strategy provides an efficient method to produce highly flexible graphene electrodes for printed electronics. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. High resolution electron microscopy studies of interfaces between Al2O3 substrates and MBE grown Nb films

    International Nuclear Information System (INIS)

    Mayer, J.; Ruhle, M.; Dura, J.; Flynn, C.P.

    1991-01-01

    This paper reports on single crystal niobium films grown by Molecular Beam Epitaxy (MBE) on (001) S sapphire substrates. Cross-sectional specimens with thickness of 2 O 3 interface could be investigated by high resolution electron microscopy (HREM). The orientation relationship between the metal film and the ceramic substrate was verified by selected area diffraction: (111) Nb parallel (0001) S and [1 bar 10] Nb parallel [2 bar 1 bar 10] S . The atomistic structure of the interface was identified by HREM

  17. One- and two-phonon mixed-symmetry states in 94Mo in high-resolution electron and proton scattering

    International Nuclear Information System (INIS)

    Fujita, H.; Botha, N.T.; Burda, O.; Carter, J.; Fearick, R.W.; Foertsch, S.V.; Fransen, C.; Kuhar, M.; Lenhardt, A.; Neumann-Cosel, P. von; Neveling, R.; Pietralla, N.; Ponomarev, V.Yu.; Richter, A.; Scholten, O.; Sideras-Haddad, E.; Smit, F.D.; Wambach, J.

    2007-01-01

    High-resolution inelastic electron scattering experiments at the S-DALINAC and proton scattering experiments at iThemba LABS permit a thorough test of the nature of proposed one- and two-phonon symmetric and mixed-symmetric 2 + states of the nucleus 94 Mo. The combined analysis reveals the one-phonon content of the mixed-symmetry state and its isovector character suggested by microscopic calculations. The purity of two-phonon 2 + states is extracted

  18. High resolution electron microscopy of the triply incommensurate phase of 2H-TaSe2

    Science.gov (United States)

    Onozuka, Takashi; Otsuka, Nobuo; Sato, Hiroshi

    1986-09-01

    The triply incommensurate phase of 2H-TaSe2 obtained by cooling from the normal phase was investigated by transmission electron microscopy between 87 and 113 K with the resolution of 3 Å, one order of magnitude better than earlier experiments. Moirélike patterns observed in this phase were confirmed to be interference fringes due to the first- and second-order diffraction beams (with small separation and possibly with higher-order diffraction beams) from the incommensurate structure and were not due to the dark-field diffraction contrast of domains of the commensurate structure as interpreted earlier. Lattice fringes (~9 Å) of this modulated phase do not show any discontinuity across the boundaries of regions of different contrasts of the moirélike fringes which is expected from domain boundaries. Instead, a periodic change in the spacing of the lattice fringes (phase-slip region) expected from the superposition of split superlattice spots in forming the lattice image is observed. This is what is believed to be the first direct observation of the existence of the phase-slip region which is also expected from the discommensuration theory. A series of observations presented here thus shows that the triply incommensurate phase is intrinsically incommensurate and suggests the need for a modification of interpretations of this phase in terms of the double honeycomb discommensuration model.

  19. Investigation of thin films, heterostructures and devices of ceramic superconductors by means of high-resolution electron microscopy

    International Nuclear Information System (INIS)

    Jia Chunlin.

    1993-08-01

    In this thesis a systematic study of the microstructure of YBa 2 Cu 3 O 7 thin films is presented by means of high-resolution electron microscopy (HREM). Most of the efforts are focused on the characterization of heterostructures of superconducting YBa 2 Cu 3 O 7 and non-superconducting PrBa 2 Cu 3 O 7 and on YBa 2 Cu 3 O 7 films deposited on step-edge substrates. These specially designed structures exhibit a great potential for the electronic application of high-Tc superconductors and for the investigation of the basic electric properties of the YBa 2 Cu 3 O 7 superconductor. (orig.) [de

  20. High-resolution, high-throughput imaging with a multibeam scanning electron microscope.

    Science.gov (United States)

    Eberle, A L; Mikula, S; Schalek, R; Lichtman, J; Knothe Tate, M L; Zeidler, D

    2015-08-01

    Electron-electron interactions and detector bandwidth limit the maximal imaging speed of single-beam scanning electron microscopes. We use multiple electron beams in a single column and detect secondary electrons in parallel to increase the imaging speed by close to two orders of magnitude and demonstrate imaging for a variety of samples ranging from biological brain tissue to semiconductor wafers. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  1. Electron-impact-induced K plus M shell ionization in solid targets of medium-Z elements studied by means of high-resolution x-ray spectroscopy

    International Nuclear Information System (INIS)

    Ludziejewski, T.; Rymuza, P.; Sujkowski, Z.; Borchert, G.; Dousse, J.; Rheme, C.; Polasik, M.

    1996-01-01

    The Kβ 2 x-ray spectra of zirconium, niobium, molybdenum, and palladium bombarded by 150 and 300 keV electrons were measured with a high-resolution transmission curved crystal spectrometer. Multiconfiguration Dirac-Fock calculations were used for the decomposition of the experimental spectra into the Kβ 2 M 0 (diagram) and Kβ 2 M 1 (satellite) components. The probabilities of energy dependent (direct Coulomb and two-step) processes were estimated from the differences in the satellite line yields for electrons and photons. The satellite yields are found to be considerably enhanced in comparison with those for the proton-induced ionization recently measured and analyzed in the same way [T. Ludziejewski et al., Phys. Rev. A 52, 2791 (1995)]. This result indicates the importance of multielectron effects in the K plus M shell ionization by energetic projectiles. copyright 1996 The American Physical Society

  2. Effects of display resolution and size on primary diagnosis of chest images using a high-resolution electronic work station

    International Nuclear Information System (INIS)

    Fuhrman, C.R.; Cooperstein, L.A.; Herron, J.; Good, W.F.; Good, B.; Gur, D.; Maitz, G.; Tabor, E.; Hoy, R.J.

    1987-01-01

    To evaluate the acceptability of electronically displayed planar images, the authors have a high-resolution work station. This system utilizes a high-resolution film digitizer (100-micro resolution) interfaced to a mainframe computer and two high-resolution (2,048 X 2,048) display devices (Azuray). In a clinically simulated multiobserver blind study (19 cases and five observers) a prodetermined series of reading sessions is stored on magnetic disk and is transferred to the displays while the preceding set of images is being reviewed. Images can be linearly processed on the fly into 2,000 X 2,000 full resolution, 1,000 X 1,000 minified display, or 1,000 X 1,000 interpolated for full-size display. Results of the study indicate that radiologists accept but do not like significant minification (more than X2), and they rate 2,000 X 2,000 images as having better diagnostic quality than 1,000 X 1,000 images

  3. Crystal interface and high-resolution electron microscopy—the best partner

    Directory of Open Access Journals (Sweden)

    H Ichinose

    2000-01-01

    Full Text Available Several contributions of HRTEM on the interface science are reviewed in chronological order. The first contribution of HRTEM is the observation of gold (113Σ°11 boundary, giving experimental proof of the CSL model. An observation of the asymmetric (112Σ°3 boundary follows. A SiC grain boundary is effectively assessed not by the density of CSL point but the number of dangling bonds in the boundary. A ZnO/Pd interface provides an example that a misfit dislocation does not necessarily accommodate the lattice mismatch. Segregated interface shows characteristic HRTEM image contrast, suggesting change in atomic bonding. An atomic height step in the semiconductor hetero interface is observed by the Chemical Lattice Image technique. In the diamond grain boundary a dangling bond may not elevate the boundary energy, being contradictory of the least dangling bond rule. Super-high resolution of the HVHRTEM enable us to determine atomic species in the grain boundary. Combined use of HRTEM and EELSE allows us to discuss the correlation between atomic structure and nature of the corresponding interface. It is not exaggeration to say that modern interface science does not exist witout HRTEM. On the other hand, many complicated interfaces found by HRTEM remained as unaswered questions. An innovative structural model is requested to appear on the scene.

  4. High-resolution electron collision spectroscopy with multicharged ions in merged beams

    Energy Technology Data Exchange (ETDEWEB)

    Lestinsky, M.

    2007-04-18

    The Heidelberg ion storage ring Tsr is currently the only ring equipped with two independent devices for the collinear merging of a cold electron beam with stored ions. This greatly improves the potential of electron-ion collision experiments, as the ion beam can be cooled with one electron beam, while the other one is used as a dedicated target for energy-resolved electron collision processes, such as recombination. The work describes the implementation of this system for rst electron collision spectroscopy experiments. A detection system has been realized including an ion detector and specroscopic beam-control software and instrumentation. Moreover, in order to improve the spectroscopic resolution systematical studies of intrinsic relaxation processes in the electron beam have been carried out. These include the dependence on the electron beam density, the magnetic guiding eld strength, and the acceleration geometry. The recombination measurements on low-lying resonances in lithiumlike Sc{sup 18+} yield a high-precision measurement of the 2s-2p{sub 3/2} transition energy in this system. Operation of the two-electron-beam setup at high collision energy ({approx}1000 eV) is established using resonances of hydrogenlike Mg{sup 11+}, while the unique possibility of modifying the beam-merging geometry con rms its importance for the electron-ion recombination rate at lowest relative energy, as demonstrated on F{sup 6+}. (orig.)

  5. High-resolution electron collision spectroscopy with multicharged ions in merged beams

    International Nuclear Information System (INIS)

    Lestinsky, M.

    2007-01-01

    The Heidelberg ion storage ring Tsr is currently the only ring equipped with two independent devices for the collinear merging of a cold electron beam with stored ions. This greatly improves the potential of electron-ion collision experiments, as the ion beam can be cooled with one electron beam, while the other one is used as a dedicated target for energy-resolved electron collision processes, such as recombination. The work describes the implementation of this system for rst electron collision spectroscopy experiments. A detection system has been realized including an ion detector and specroscopic beam-control software and instrumentation. Moreover, in order to improve the spectroscopic resolution systematical studies of intrinsic relaxation processes in the electron beam have been carried out. These include the dependence on the electron beam density, the magnetic guiding eld strength, and the acceleration geometry. The recombination measurements on low-lying resonances in lithiumlike Sc 18+ yield a high-precision measurement of the 2s-2p 3/2 transition energy in this system. Operation of the two-electron-beam setup at high collision energy (∼1000 eV) is established using resonances of hydrogenlike Mg 11+ , while the unique possibility of modifying the beam-merging geometry con rms its importance for the electron-ion recombination rate at lowest relative energy, as demonstrated on F 6+ . (orig.)

  6. Quantitative analysis of localized stresses in irradiated stainless steels using high resolution electron backscatter diffraction and molecular dynamics modeling

    International Nuclear Information System (INIS)

    Johnson, D.C.; Kuhr, B.; Farkas, D.; Was, G.S.

    2016-01-01

    Quantitative measurements of stress near dislocation channel–grain boundary (DC–GB) interaction sites were made using high resolution electron backscatter diffraction (HREBSD) and have been compared with molecular dynamics (MD) simulations. Tensile stress normal to the grain boundary was significantly elevated at discontinuous DC–GB intersections with peak magnitudes roughly an order of magnitude greater than at sites where slip transfer occurred. These results constitute the first measurement of stress amplification at DC–GB intersections and provide support to the theory that high normal stress at the grain boundary may be a key driver for the initiation of irradiation assisted stress corrosion cracks.

  7. High resolution electron energy loss spectroscopy of clean and hydrogen covered Si(001) surfaces: first principles calculations.

    Science.gov (United States)

    Patterson, C H

    2012-09-07

    Surface phonons, conductivities, and loss functions are calculated for reconstructed (2×1), p(2×2) and c(4×2) clean Si(001) surfaces, and (2×1) H and D covered Si(001) surfaces. Surface conductivities perpendicular to the surface are significantly smaller than conductivities parallel to the surface. The surface loss function is compared to high resolution electron energy loss measurements. There is good agreement between calculated loss functions and experiment for H and D covered surfaces. However, agreement between experimental data from different groups and between theory and experiment is poor for clean Si(001) surfaces. Formalisms for calculating electron energy loss spectra are reviewed and the mechanism of electron energy losses to surface vibrations is discussed.

  8. Impact of measuring electron tracks in high-resolution scientific charge-coupled devices within Compton imaging systems

    International Nuclear Information System (INIS)

    Chivers, D.H.; Coffer, A.; Plimley, B.; Vetter, K.

    2011-01-01

    We have implemented benchmarked models to determine the gain in sensitivity of electron-tracking based Compton imaging relative to conventional Compton imaging by the use of high-resolution scientific charge-coupled devices (CCD). These models are based on the recently demonstrated ability of electron-tracking based Compton imaging by using fully depleted scientific CCDs. Here we evaluate the gain in sensitivity by employing Monte Carlo simulations in combination with advanced charge transport models to calculate two-dimensional charge distributions corresponding to experimentally obtained tracks. In order to reconstruct the angle of the incident γ-ray, a trajectory determination algorithm was used on each track and integrated into a back-projection routine utilizing a geodesic-vertex ray tracing technique. Analysis was performed for incident γ-ray energies of 662 keV and results show an increase in sensitivity consistent with tracking of the Compton electron to approximately ±30 o .

  9. High-Resolution of Electron Microscopy of Montmorillonite and Montmorillonite/Epoxy Nanocomposites

    National Research Council Canada - National Science Library

    Drummy, Lawrence F; Farmer, Karen; Tan, Ashley; Farmer, B. L; Vaia, Richard A; Koerner, Hilmar

    2005-01-01

    .... These procedures involve careful control of the microscope's objective lens defocus to maximize contrast from features of certain size, as well as limiting the total dose of electrons received by the sample...

  10. Transmission electron microscopy physics of image formation and microanalysis

    CERN Document Server

    Reimer, Ludwig

    1997-01-01

    Transmission Electron Microscopy presents the theory of image and contrast formation, and the analytical modes in transmission electron microscopy. The principles of particle and wave optics of electrons are described. Electron-specimen interactions are discussed for evaluating the theory of scattering and phase contrast. Also discussed are the kinematical and dynamical theories of electron diffraction and their applications for crystal-structure analysis and imaging of lattices and their defects. X-ray micronanalysis and electron energy-loss spectroscopy are treated as analytical methods. Specimen damage and contamination by electron irradiation limits the resolution for biological and some inorganic specimens. This fourth edition includes discussion of recent progress, especially in the area of Schottky emission guns, convergent-beam electron diffraction, electron tomography, holography and the high resolution of crystal lattices.

  11. A low cost high resolution pattern generator for electron-beam lithography

    International Nuclear Information System (INIS)

    Pennelli, G.; D'Angelo, F.; Piotto, M.; Barillaro, G.; Pellegrini, B.

    2003-01-01

    A simple, very low cost pattern generator for electron-beam lithography is presented. When it is applied to a scanning electron microscope, the system allows a high precision positioning of the beam for lithography of very small structures. Patterns are generated by a suitable software implemented on a personal computer, by using very simple functions, allowing an easy development of new writing strategies for a great adaptability to different user necessities. Hardware solutions, as optocouplers and battery supply, have been implemented for reduction of noise and disturbs on the voltages controlling the positioning of the beam

  12. Electron beam excitation assisted optical microscope with ultra-high resolution.

    Science.gov (United States)

    Inami, Wataru; Nakajima, Kentaro; Miyakawa, Atsuo; Kawata, Yoshimasa

    2010-06-07

    We propose electron beam excitation assisted optical microscope, and demonstrated its resolution higher than 50 nm. In the microscope, a light source in a few nanometers size is excited by focused electron beam in a luminescent film. The microscope makes it possible to observe dynamic behavior of living biological specimens in various surroundings, such as air or liquids. Scan speed of the nanometric light source is faster than that in conventional near-field scanning optical microscopes. The microscope enables to observe optical constants such as absorption, refractive index, polarization, and their dynamic behavior on a nanometric scale. The microscope opens new microscopy applications in nano-technology and nano-science.

  13. Inner shell excitation in atoms and molecules by high resolution electron impact

    International Nuclear Information System (INIS)

    King, G.C.

    1986-01-01

    In this work an inner-shell spin-forbidden transition in N 2 and a parity-forbidden transition in Ar were studied. These transitions were observed by using incident electron energies as low as 1.15 times the excitation energy of the inner-shell states. (Auth.)

  14. Efficient creation of electron vortex beams for high resolution STEM imaging.

    Science.gov (United States)

    Béché, A; Juchtmans, R; Verbeeck, J

    2017-07-01

    The recent discovery of electron vortex beams carrying quantised angular momentum in the TEM has led to an active field of research, exploring a variety of potential applications including the possibility of mapping magnetic states at the atomic scale. A prerequisite for this is the availability of atomic sized electron vortex beams at high beam current and mode purity. In this paper we present recent progress showing that by making use of the Aharonov-Bohm effect near the tip of a long single domain ferromagnetic Nickel needle, a very efficient aperture for the production of electron vortex beams can be realised. The aperture transmits more than 99% of all electrons and provides a vortex mode purity of up to 92%. Placing this aperture in the condenser plane of a state of the art Cs corrected microscope allows us to demonstrate atomic resolution HAADF STEM images with spatial resolution better than 1 Angström, in agreement with theoretical expectations and only slightly inferior to the performance of a non-vortex probe on the same instrument. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. [A high resolution projection electron spectrometers]: Final report 1978-1987

    International Nuclear Information System (INIS)

    1988-01-01

    The main emphasis of the work has been to study inner shell ionization processes. The signatures have been K x-rays or K Auger transitions. We have worked with semiconductor or Bragg x-ray spectrometers. Toward the end of the contract we concentrated on projectile electron spectroscopy. These topics and other atomic physics projects are described briefly in this progress report

  16. High-Resolution Two-Dimensional Optical Spectroscopy of Electron Spins

    Directory of Open Access Journals (Sweden)

    M. Salewski

    2017-08-01

    Full Text Available Multidimensional coherent optical spectroscopy is one of the most powerful tools for investigating complex quantum mechanical systems. While it was conceived decades ago in magnetic resonance spectroscopy using microwaves and radio waves, it has recently been extended into the visible and UV spectral range. However, resolving MHz energy splittings with ultrashort laser pulses still remains a challenge. Here, we analyze two-dimensional Fourier spectra for resonant optical excitation of resident electrons to localized trions or donor-bound excitons in semiconductor nanostructures subject to a transverse magnetic field. Particular attention is devoted to Raman coherence spectra, which allow one to accurately evaluate tiny splittings of the electron ground state and to determine the relaxation times in the electron spin ensemble. A stimulated steplike Raman process induced by a sequence of two laser pulses creates a coherent superposition of the ground-state doublet which can be retrieved only optically because of selective excitation of the same subensemble with a third pulse. This provides the unique opportunity to distinguish between different complexes that are closely spaced in energy in an ensemble. The related experimental demonstration is based on photon-echo measurements in an n-type CdTe/(Cd,MgTe quantum-well structure detected by a heterodyne technique. The difference in the sub-μeV range between the Zeeman splittings of donor-bound electrons and electrons localized at potential fluctuations can be resolved even though the homogeneous linewidth of the optical transitions is larger by 2 orders of magnitude.

  17. Core polarisation and configuration mixing in 58Ni studied by high resolution electron scattering

    International Nuclear Information System (INIS)

    Blok, H.

    1986-01-01

    The nucleus 58 Ni is studied by inelastic electron-scattering. This nucleus has two valence neutrons outside a closed 58 Ni core which implies that no valence protons contribute to the transitions and thus, besides configuration mixing of the valence neutrons, proton-core polarization can be studied in detail. From inelastic electron-scattering data one obtains the charge- and current-transition densities by determining the Fourier-Bessel transform of the cross sections measured over a wide range of linear momenta transferred to the nucleus. The results of an analysis of the excitation of two 0 ++ states at low-momentum transfer are presented. These transitions are particularly interesting for studying core-polarization contributions. (Auth.)

  18. Low-energy magnetic dipole response in 56Fe from high-resolution electron scattering

    International Nuclear Information System (INIS)

    Fearick, R.W.; Hartung, G.; Langanke, K.; Martinez-Pinedo, G.; Neumann-Cosel, P. von; Richter, A.

    2003-01-01

    The 56 Fe(e, e') reaction has been studied for excitation energies up to about 8 MeV and momentum transfers q≅0.4-0.55 fm -1 at the Darmstadt electron linear accelerator (DALINAC) with kinematics emphasizing M1 transitions. Additional data have been taken for q≅0.8-1.7 fm -1 at the electron accelerator NIKHEF, Amsterdam. A PWBA analysis allows spin and parity determination of the excited states. For M1 excitations, transition strengths are derived with a DWBA analysis using shell-model form factors. The resulting B(M1) strength distribution is compared to shell-model calculations employing different effective interactions. The form factor of the prominent low-lying M1 transition at 3.449 MeV demonstrates its dominant orbital nature. It represents a major part of the scissors mode in 56 Fe

  19. High resolution electron exit wave reconstruction from a diffraction pattern using Gaussian basis decomposition

    International Nuclear Information System (INIS)

    Borisenko, Konstantin B; Kirkland, Angus I

    2014-01-01

    We describe an algorithm to reconstruct the electron exit wave of a weak-phase object from single diffraction pattern. The algorithm uses analytic formulations describing the diffraction intensities through a representation of the object exit wave in a Gaussian basis. The reconstruction is achieved by solving an overdetermined system of non-linear equations using an easily parallelisable global multi-start search with Levenberg-Marquard optimisation and analytic derivatives

  20. High-resolution broadband terahertz spectroscopy via electronic heterodyne detection of photonically generated terahertz frequency comb.

    Science.gov (United States)

    Pavelyev, D G; Skryl, A S; Bakunov, M I

    2014-10-01

    We report an alternative approach to the terahertz frequency-comb spectroscopy (TFCS) based on nonlinear mixing of a photonically generated terahertz pulse train with a continuous wave signal from an electronic synthesizer. A superlattice is used as a nonlinear mixer. Unlike the standard TFCS technique, this approach does not require a complex double-laser system but retains the advantages of TFCS-high spectral resolution and wide bandwidth.

  1. High resolution electron scattering facility at the Darmstadt Linear Accelerator (DALINAC). Pt. 4

    International Nuclear Information System (INIS)

    Foh, J.; Frey, R.; Schneider, R.; Schuell, D.; Schwierczinski, A.; Theissen, H.; Titze, O.

    1977-11-01

    The computer system installed for the electron scattering facility and its usage is described. For on-line control a dedicated system of two tightly coupled computers (PDP 11/20, H116) is used wheras a PDP 11/45 is provided for all other data processing work resulting from the experiments. Special interfaces, graphic terminals, system software and a complete set of application programs have been developed. (orig.) [de

  2. Development of an Apparatus for High-Resolution Auger Photoelectron Coincidence Spectroscopy (APECS) and Electron Ion Coincidence (EICO) Spectroscopy

    Science.gov (United States)

    Kakiuchi, Takuhiro; Hashimoto, Shogo; Fujita, Narihiko; Mase, Kazuhiko; Tanaka, Masatoshi; Okusawa, Makoto

    We have developed an electron electron ion coincidence (EEICO) apparatus for high-resolution Auger photoelectron coincidence spectroscopy (APECS) and electron ion coincidence (EICO) spectroscopy. It consists of a coaxially symmetric mirror electron energy analyzer (ASMA), a miniature double-pass cylindrical mirror electron energy analyzer (DP-CMA), a miniature time-of-flight ion mass spectrometer (TOF-MS), a magnetic shield, an xyz stage, a tilt-adjustment mechanism, and a conflat flange with an outer diameter of 203 mm. A sample surface was irradiated by synchrotron radiation, and emitted electrons were energy-analyzed and detected by the ASMA and the DP-CMA, while desorbed ions were mass-analyzed and detected by the TOF-MS. The performance of the new EEICO analyzer was evaluated by measuring Si 2p photoelectron spectra of clean Si(001)-2×1 and Si(111)-7×7, and by measuring Si-L23VV-Si-2p Auger photoelectron coincidence spectra (Si-L23VV-Si-2p APECS) of clean Si(001)-2×1.

  3. Recent Developments of an Opto-Electronic THz Spectrometer for High-Resolution Spectroscopy

    Directory of Open Access Journals (Sweden)

    Guillaume Ducournau

    2009-11-01

    Full Text Available A review is provided of sources and detectors that can be employed in the THz range before the description of an opto-electronic source of monochromatic THz radiation. The realized spectrometer has been applied to gas phase spectroscopy. Air-broadening coefficients of HCN are determined and the insensitivity of this technique to aerosols is demonstrated by the analysis of cigarette smoke. A multiple pass sample cell has been used to obtain a sensitivity improvement allowing transitions of the volatile organic compounds to be observed. A solution to the frequency metrology is presented and promises to yield accurate molecular line center measurements.

  4. Recent Developments of an Opto-Electronic THz Spectrometer for High-Resolution Spectroscopy.

    Science.gov (United States)

    Hindle, Francis; Yang, Chun; Mouret, Gael; Cuisset, Arnaud; Bocquet, Robin; Lampin, Jean-François; Blary, Karine; Peytavit, Emilien; Akalin, Tahsin; Ducournau, Guillaume

    2009-01-01

    A review is provided of sources and detectors that can be employed in the THz range before the description of an opto-electronic source of monochromatic THz radiation. The realized spectrometer has been applied to gas phase spectroscopy. Air-broadening coefficients of HCN are determined and the insensitivity of this technique to aerosols is demonstrated by the analysis of cigarette smoke. A multiple pass sample cell has been used to obtain a sensitivity improvement allowing transitions of the volatile organic compounds to be observed. A solution to the frequency metrology is presented and promises to yield accurate molecular line center measurements.

  5. Recent Developments of an Opto-Electronic THz Spectrometer for High-Resolution Spectroscopy

    Science.gov (United States)

    Hindle, Francis; Yang, Chun; Mouret, Gael; Cuisset, Arnaud; Bocquet, Robin; Lampin, Jean-François; Blary, Karine; Peytavit, Emilien; Akalin, Tahsin; Ducournau, Guillaume

    2009-01-01

    A review is provided of sources and detectors that can be employed in the THz range before the description of an opto-electronic source of monochromatic THz radiation. The realized spectrometer has been applied to gas phase spectroscopy. Air-broadening coefficients of HCN are determined and the insensitivity of this technique to aerosols is demonstrated by the analysis of cigarette smoke. A multiple pass sample cell has been used to obtain a sensitivity improvement allowing transitions of the volatile organic compounds to be observed. A solution to the frequency metrology is presented and promises to yield accurate molecular line center measurements. PMID:22291552

  6. High-Resolution Electron-Impact Study of the Far-Ultraviolet Emission Spectrum of Molecular Hydrogen

    Science.gov (United States)

    Liu, Xian-Ming; Ahmed, Syed M.; Multari, Rosalie A.; James, Geoffrey K.; Ajello, Joseph M.

    1995-01-01

    The emission spectrum of molecular hydrogen produced by electron-impact excitation at 100 eV has been measured in the wavelength range 1140-1690 A. High-resolution, optically thin spectra (delta(lambda) = 0.136 A) of the far-ultraviolet (FUV) Lyman and Werner band systems have been obtained with a newly constructed 3 m spectrometer. Synthetic spectral intensities based on the transition probabilities calculated by Abgrall et al. are in very good agreement with experimentally observed intensities. Previous modeling that utilized Allison & Daigarno band transition probabilities with Hoenl-London factors breaks down when the transition moment has significant J dependence or when ro-vibrational coupling is significant. Ro-vibrational perturbation between upsilon = 14 of the B(sup 1)Sigma(sup +, sub u) state and upsilon = 3 of the C(sup 1)Pi(sub u) state and the rotational dependence of the transition moment in the bands of the Lyman system are examined. Complete high-resolution experimental reference FUV spectra, together with the model synthetic spectra based on the Abgrall transition probabilities, are presented. An improved calibration standard is obtained, and an accurate calibration of the 3 m spectrometer has been achieved.

  7. Preservation of high resolution protein structure by cryo-electron microscopy of vitreous sections

    International Nuclear Information System (INIS)

    Sader, Kasim; Studer, Daniel; Zuber, Benoit; Gnaegi, Helmut; Trinick, John

    2009-01-01

    We have quantitated the degree of structural preservation in cryo-sections of a vitrified biological specimen. Previous studies have used sections of periodic specimens to assess the resolution present, but preservation before sectioning was not assessed and so the damage due particularly to cutting was not clear. In this study large single crystals of lysozyme were vitrified and from these X-ray diffraction patterns extending to better than 2.1 A were obtained. The crystals were high pressure frozen in 30% dextran, and cryo-sectioned using a diamond knife. In the best case, preservation to a resolution of 7.9 A was shown by electron diffraction, the first observation of sub-nanometre structural preservation in a vitreous section.

  8. High-resolution analytical imaging and electron holography of magnetite particles in amyloid cores of Alzheimer’s disease

    Science.gov (United States)

    Plascencia-Villa, Germán; Ponce, Arturo; Collingwood, Joanna F.; Arellano-Jiménez, M. Josefina; Zhu, Xiongwei; Rogers, Jack T.; Betancourt, Israel; José-Yacamán, Miguel; Perry, George

    2016-01-01

    Abnormal accumulation of brain metals is a key feature of Alzheimer’s disease (AD). Formation of amyloid-β plaque cores (APC) is related to interactions with biometals, especially Fe, Cu and Zn, but their particular structural associations and roles remain unclear. Using an integrative set of advanced transmission electron microscopy (TEM) techniques, including spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM), nano-beam electron diffraction, electron holography and analytical spectroscopy techniques (EDX and EELS), we demonstrate that Fe in APC is present as iron oxide (Fe3O4) magnetite nanoparticles. Here we show that Fe was accumulated primarily as nanostructured particles within APC, whereas Cu and Zn were distributed through the amyloid fibers. Remarkably, these highly organized crystalline magnetite nanostructures directly bound into fibrillar Aβ showed characteristic superparamagnetic responses with saturated magnetization with circular contours, as observed for the first time by off-axis electron holography of nanometer scale particles. PMID:27121137

  9. The digital structural analysis of cadmium selenide crystals by a method of ion beam thinning for high resolution electron microscopy

    International Nuclear Information System (INIS)

    Kanaya, Koichi; Baba, Norio; Naka, Michiaki; Kitagawa, Yukihisa; Suzuki, Kunio

    1986-01-01

    A digital processing method using a scanning densitometer system for structural analysis of electron micrographs was successfully applied to a study of cadmium selenide crystals, which were prepared by an argon-ion beam thinning method. Based on Fourier techniques for structural analysis from a computer-generated diffractogram, it was demonstrated that when cadmium selenide crystals were sufficiently thin to display the higher order diffraction spots at a high resolution approaching the atomic level, they constitute an alternative hexagonal lattice of imperfect wurtzite phase from a superposition of individual harmonic images by the enhanced scattering amplitude and corrected phase. From the structural analysis data, a Fourier synthetic lattice image was reconstructed, representing the precise location and three-dimensional arrangement of each of the atoms in the unit cell. Extensively enhanced lattice defect images of dislocations and stacking faults were also derived and shown graphically. (author)

  10. Superstructure of the superconductor BI2Sr2CaCu2O8 by high resolution electron microscopy

    International Nuclear Information System (INIS)

    Hewat, E.A.

    1988-01-01

    The superstructure of the high Tc superconducting oxide BI 2S r 2C aCu 2 0 8 has been studied by high resolution electron microscopy. Waves of distortion along the b-axis give an incommensurate superlattice slightly larger or smaller than 5√2a p (a p = perovskite unit cell). The building blocks along the b-axis are 4, 5 and 6 times √2a p /2. The incommensurate superlattice is composed of approximately periodic combinations of these building blocks. The symmetry of three major projections are P gm (or possibly P gg ), C mm and C mm for the ideal superlattice with b=5√ 2a p . These projections correspond to the space groups Pcnn and Pmnn respectively

  11. High-resolution electron microscopy on incommensurate long-period superstructures of hexagonal-close-packed Cu-Sb alloy

    International Nuclear Information System (INIS)

    Onozuka, T.; Kakehashi, S.; Takahashi, T.; Hirabayashi, M.

    1989-01-01

    Hexagonal incommensurate long-period superstructures of the Cu-Sb alloys containing 18-20 at.% Sb have been investigated by means of superstructure imaging using a high-resolution electron microscope. Honeycomb-type distributions of hexagonal domains consisting of the commensurate superstructure of type 7a 0 -2H are observed. The incommensurabilities of superstructure can be interpreted well with a hexagonal model composed of the 7a 0 -2H domains surrounded by domain walls which contain higher Sb content than the domain interior. The observed image contrast is reproduced well with multislice computer simulations based on the structure models proposed for the 7a 0 -2H domain and the domain wall. (orig.)

  12. High-resolution electron microscopy on incommensurate long-period superstructures of hexagonal-close-packed Cu-Sb alloy

    Energy Technology Data Exchange (ETDEWEB)

    Onozuka, T.; Kakehashi, S.; Takahashi, T.; Hirabayashi, M. (Tohoku Univ., Sendai (Japan). Inst. for Materials Research)

    1989-06-01

    Hexagonal incommensurate long-period superstructures of the Cu-Sb alloys containing 18-20 at.% Sb have been investigated by means of superstructure imaging using a high-resolution electron microscope. Honeycomb-type distributions of hexagonal domains consisting of the commensurate superstructure of type 7a{sub 0}-2H are observed. The incommensurabilities of superstructure can be interpreted well with a hexagonal model composed of the 7a{sub 0}-2H domains surrounded by domain walls which contain higher Sb content than the domain interior. The observed image contrast is reproduced well with multislice computer simulations based on the structure models proposed for the 7a{sub 0}-2H domain and the domain wall. (orig.).

  13. Phonon spectrum of single-crystalline FeSe probed by high-resolution electron energy-loss spectroscopy

    Science.gov (United States)

    Zakeri, Khalil; Engelhardt, Tobias; Le Tacon, Matthieu; Wolf, Thomas

    2018-06-01

    Utilizing high-resolution electron energy-loss spectroscopy (HREELS) we measure the phonon frequencies of β-FeSe(001), cleaved under ultra-high vacuum conditions. At the zone center (Γ bar-point) three prominent loss features are observed at loss energies of about ≃ 20.5 and 25.6 and 40 meV. Based on the scattering selection rules we assign the observed loss features to the A1g, B1g, and A2u phonon modes of β-FeSe(001). The experimentally measured phonon frequencies do not agree with the results of density functional based calculations in which a nonmagnetic, a checkerboard or a strip antiferromagnetic order is assumed for β-FeSe(001). Our measurements suggest that, similar to the other Fe-based materials, magnetism has a profound impact on the lattice dynamics of β-FeSe(001).

  14. Hard x-ray monochromator with milli-electron volt bandwidth for high-resolution diffraction studies of diamond crystals

    Energy Technology Data Exchange (ETDEWEB)

    Stoupin, Stanislav; Shvyd' ko, Yuri; Shu Deming; Khachatryan, Ruben; Xiao, Xianghui; DeCarlo, Francesco; Goetze, Kurt; Roberts, Timothy; Roehrig, Christian; Deriy, Alexey [Advanced Photon Source, Argonne National Laboratory, Illinois 60439 (United States)

    2012-02-15

    We report on design and performance of a high-resolution x-ray monochromator with a spectral bandwidth of {Delta}E{sub X}{approx_equal} 1.5 meV, which operates at x-ray energies in the vicinity of the backscattering (Bragg) energy E{sub H} = 13.903 keV of the (008) reflection in diamond. The monochromator is utilized for high-energy-resolution diffraction characterization of diamond crystals as elements of advanced x-ray crystal optics for synchrotrons and x-ray free-electron lasers. The monochromator and the related controls are made portable such that they can be installed and operated at any appropriate synchrotron beamline equipped with a pre-monochromator.

  15. Combining scanning tunneling microscopy and synchrotron radiation for high-resolution imaging and spectroscopy with chemical, electronic, and magnetic contrast

    International Nuclear Information System (INIS)

    Cummings, M.L.; Chien, T.Y.; Preissner, C.; Madhavan, V.; Diesing, D.; Bode, M.; Freeland, J.W.; Rose, V.

    2012-01-01

    The combination of high-brilliance synchrotron radiation with scanning tunneling microscopy opens the path to high-resolution imaging with chemical, electronic, and magnetic contrast. Here, the design and experimental results of an in-situ synchrotron enhanced x-ray scanning tunneling microscope (SXSTM) system are presented. The system is designed to allow monochromatic synchrotron radiation to enter the chamber, illuminating the sample with x-ray radiation, while an insulator-coated tip (metallic tip apex open for tunneling, electron collection) is scanned over the surface. A unique feature of the SXSTM is the STM mount assembly, designed with a two free-flex pivot, providing an angular degree of freedom for the alignment of the tip and sample with respect to the incoming x-ray beam. The system designed successfully demonstrates the ability to resolve atomic-scale corrugations. In addition, experiments with synchrotron x-ray radiation validate the SXSTM system as an accurate analysis technique for the study of local magnetic and chemical properties on sample surfaces. The SXSTM system's capabilities have the potential to broaden and deepen the general understanding of surface phenomena by adding elemental contrast to the high-resolution of STM. -- Highlights: ► Synchrotron enhanced x-ray scanning tunneling microscope (SXSTM) system designed. ► Unique STM mount design allows angular DOF for tip alignment with x-ray beam. ► System demonstrates ability to resolve atomic corrugations on HOPG. ► Studies show chemical sensitivity with STM tip from photocurrent and tunneling. ► Results show system's ability to study local magnetic (XMCD) properties on Fe films.

  16. Transmission electron microscopy of bone

    NARCIS (Netherlands)

    Everts, Vincent; Niehof, Anneke; Tigchelaar-Gutter, Wikky; Beertsen, Wouter

    2012-01-01

    This chapter describes procedures to process mineralized tissues obtained from different sources for transmission electron microscopy (TEM). Methods for fixation, resin embedding, staining of semi-thin sections and ultrathin sections are presented. In addition, attention will be paid to processing

  17. Structural evolution of a deformed Σ=9 (122) grain boundary in silicon. A high resolution electron microscopy study

    International Nuclear Information System (INIS)

    Putaux, Jean-Luc

    1991-01-01

    This research thesis addresses the study by high resolution electron microscopy of the evolution of a silicon bi-crystal under deformation at different temperatures. The author notably studied the structural evolution of the boundary as well as that of grains at the vicinity of the boundary. Two observation scales have been used: the evolution of sub-structures of dislocations induced by deformation in grains and in boundary, and the structure of all defects at an atomic scale. After a presentation of experimental tools (the necessary perfect quality of the electronic optics is outlined), the author recalls some descriptive aspects of grain boundaries (geometric network concepts to describe coinciding networks, concepts of delimiting boundaries and of structural unit to describe grain boundary atomic structure), recalls the characteristics of the studied bi-crystal, and the conditions under which it is deformed. He presents the structures of all perfectly coinciding boundaries, describes defects obtained by deformation at the vicinity of the boundary, describes the entry of dissociated dislocations into the boundaries, and discusses the characterization of boundary dislocations (the notion of Burgers vector is put into question again), and the atomic mechanism of displacement of dislocations in boundaries [fr

  18. High-resolution electron-energy-loss spectroscopy studies of clean and hydrogen-covered tungsten (100) surfaces

    International Nuclear Information System (INIS)

    Woods, J.P.

    1986-01-01

    High-resolution (10-meV FWHM) low-energy (≤ 100eV) electrons are scattered from the tungsten (100) surface. Electron-energy-loss spectroscopy (EELS) selection rules are utilized to identify vibrational modes of the surface tungsten atoms. A 36-meV mode is measured on the c(2 X 2) thermally reconstructed surface and is modeled as an overtone of the 18-meV mode at M in the surface Brillouin zone. The superstructure of the reconstructed surface allows this mode to be observed in specular scattering. The surface tungsten atoms return to their bulk lateral positions with saturated hydrogen (β 1 phase) adsorption; and a 26-meV mode identified is due to the perpendicular vibration of the surface tungsten layers. The clean-room temperature surface does not display either low-energy vibrations and the surface is modeled as disordered. The three β 1 phase hydrogen vibrations are observed and a new vibration at 118 meV is identified. The 118-meV cross section displays characteristics of a parallel mode, but calculations show this assignment to be erroneous. There are two hydrogen atoms for each surface tungsten atom in the β 1 phase, and lattice-dynamical calculations show that the 118-meV mode is due to a hydrogen-zone edge vibration. The predicted breakdown of the parallel hydrogen vibration selection rule was not observed

  19. High resolution electron microscopy and electron diffraction of YBa/sub 2/Cu/sub 3/O/sub 7-x/

    International Nuclear Information System (INIS)

    Krakow, W.; Shaw, T.M.

    1988-01-01

    Experimental high resolution electron micrographs and computer simulation experiments have been used to evaluate the visibility of the atomic constituents of YBa/sub 2/Cu/sub 3/O/sub 7-x/. In practice, the detection of oxygen has not been possible in contradiction to that predicted by modelling of perfect crystalline material. Preliminary computer experiments of the electron diffraction patterns when oxygen vacancies are introduced on the Cu-O sheets separating Ba layers show the diffuse streaks characteristic of short range ordering

  20. The neural elements in the lining of the ventricular-subventricular zone: making an old story new by high-resolution scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Carlos Alexandre Dos Santos Haemmerle

    2015-10-01

    Full Text Available The classical description of the neural elements that compose the lining of brain ventricles introduces us to the single layer of ependymal cells. However, new findings, especially in the lateral ventricle - the major niche for the generation of new neurons in the adult brain - have provided information about additional cell elements that influence the organization of this part of the ventricular system and produce important contributions to neurogenesis. To complement the cell neurochemistry findings, we present a three-dimensional in situ description that demonstrates the anatomical details of the different types of ciliated cells and the innervation of these elements. After processing adult rat brains for ultrastructural analysis by high-resolution scanning electron microscopy and transmission electron microscopy, we observed a heterogeneous pattern of cilia distribution at the different poles of the lateral ventricle surface. Furthermore, we describe the particular three-dimensional aspects of the ciliated cells of the lateral ventricle, in addition the fiber bundles and varicose axons surrounding these cells. Therefore, we provide a unique ultrastructural description of the three-dimensional in situ organization of the lateral ventricle surface, highlighting its innervation, to corroborate the available neurochemical and functional findings regarding the factors that regulate this neurogenic niche.

  1. Optimal thickness of a monocrystal line object in atomic plane visualization on its image in a high-resolution electron microscope

    International Nuclear Information System (INIS)

    Grishina, T.A.; Sviridova, V.Yu.

    1983-01-01

    Theoretical and experimental investigation of the influence of the FCC-lattice crystal (gold, nickel) thickness on conditions of visulization of atomic plane projections (APP) on the crystal image in a transmission high-resolution electron microscope (THREM) is reported. Results of electron diffraction theory are used for theoretical investigation. Calculation analysis of the influence of the monocrystal thickness and orientation on conitions of visualization of APP and atomic columns in monocrystal images formed in THREM in multibeam regimes with inclined and axial illumination is conducted. It is shown that, to visualize the atomic column projections in a crystal image formed in the multibeam regime with axial illumination, optimal are the thicknesses from 0.1 xisub(min) to 0.25 xisub(min) and at some object orientations also the thicknesses from 0.8 xisub(min) to 0.9 xisub(min), where xisub(min) is the extinction length minimum for the given orientation. It is shown that, to realize the ultimate resolutions in multibeam regimes both with inclined and axial illumination the optimal thickness of the object is 0.63 xisub(min). Satisfactory coincidence of theoretical and experimental data is obtained

  2. High resolution imaging of boron carbide microstructures

    International Nuclear Information System (INIS)

    MacKinnon, I.D.R.; Aselage, T.; Van Deusen, S.B.

    1986-01-01

    Two samples of boron carbide have been examined using high resolution transmission electron microscopy (HRTEM). A hot-pressed B 13 C 2 sample shows a high density of variable width twins normal to (10*1). Subtle shifts or offsets of lattice fringes along the twin plane and normal to approx.(10*5) were also observed. A B 4 C powder showed little evidence of stacking disorder in crystalline regions

  3. High resolution inelastic electron scattering on 90Zr at low momentum transfer and strong fragmentation of the magnetic quadrupole strength

    International Nuclear Information System (INIS)

    Meuer, D.; Frey, R.; Hoffmann, D.H.H.; Richter, A.; Spamer, E.; Titze, O.; Knuepfer, W.

    1980-01-01

    High-resolution (FWHM approx. 30 keV) inelastic electron scattering on 90 Zr at low momentum transfer (0.20 -1 ) has been used to study magnetic transitions at excitation energies Esub(x) = 8-10 MeV. The experimental data were analyzed in the distorted-wave Born approximation (DWBA) with wave functions calculated in the random phase approximation (RPA). Three Jsup(π) = 1 + states have been identified Esub(x) = 8.233, 9.000 and 9.371 MeV. There is some indication of further very fragmented dipole strength and the upper limit for the total M1 strength in the investigated energy region is ΣB(M1)up 2 sub(K). It is much smaller than any theoretical prediction. Furthermore, a large number of 2 - states has been observed, with the center of gravity located at Esub(x) approx. 9 MeV. These states carry a total strength of ΣB(M2)up = 1000 μ 2 sub(K) x fm 2 . Their strong fragmentation is in qualitative agreement with theoretical calculations, but the deduced strength is much smaller than theoretically predicted. In addition the distributions of spacings and radiative widths of the 2 - states are consistent with a Wigner and a Porter-Thomas distribution, respectively. (orig.)

  4. High-resolution electron-microscopic studies of the polymorphs in Ag2±δSe films

    International Nuclear Information System (INIS)

    Okabe, Toshio; Ura, Katsuhiko

    1994-01-01

    The polymorphs that appear in the low-temperature phase of silver selenide have been studied by high-resolution electron microscopy. The specimen films are intentionally prepared with excess silver or selenium over stoichiometric composition by flash evaporation, as-depositing carbon films on both sides of the specimen films to protect them from selenium sublimation and to maintain the composition throughout the heat treatment. It is shown that four different types of low-temperature phase exist: tetragonal (a = 6.98, c = 4.96 A) for a metastable phase only formed with a small grain size of less than 50 nm; face-centred cubic (a = 10.9 A) for a non-stoichiometric phase with excess silver; monoclinic (a = 7.05, b = 8.17, c = 4.34 A, α = 101.0 ) for a non-stoichiometric phase with excess selenium; and orthorhombic (a = 7.05, b 7.82, c = 4.34 A) for the stoichiometric stable phase. The topotactic relations between the orthorhombic and monoclinic types are found to be fully coherent, having the same a and c lattice parameters. (orig.)

  5. Automated analysis of heterogeneous carbon nanostructures by high-resolution electron microscopy and on-line image processing

    International Nuclear Information System (INIS)

    Toth, P.; Farrer, J.K.; Palotas, A.B.; Lighty, J.S.; Eddings, E.G.

    2013-01-01

    High-resolution electron microscopy is an efficient tool for characterizing heterogeneous nanostructures; however, currently the analysis is a laborious and time-consuming manual process. In order to be able to accurately and robustly quantify heterostructures, one must obtain a statistically high number of micrographs showing images of the appropriate sub-structures. The second step of analysis is usually the application of digital image processing techniques in order to extract meaningful structural descriptors from the acquired images. In this paper it will be shown that by applying on-line image processing and basic machine vision algorithms, it is possible to fully automate the image acquisition step; therefore, the number of acquired images in a given time can be increased drastically without the need for additional human labor. The proposed automation technique works by computing fields of structural descriptors in situ and thus outputs sets of the desired structural descriptors in real-time. The merits of the method are demonstrated by using combustion-generated black carbon samples. - Highlights: ► The HRTEM analysis of heterogeneous nanostructures is a tedious manual process. ► Automatic HRTEM image acquisition and analysis can improve data quantity and quality. ► We propose a method based on on-line image analysis for the automation of HRTEM image acquisition. ► The proposed method is demonstrated using HRTEM images of soot particles

  6. High-resolution electron microscopy study of Ni81Fe19 film with Co33Cr67 buffer layer

    International Nuclear Information System (INIS)

    Xu, Q.Y.; Wang, Z.M.; Shen, F.; Du, Y.W.; Zhang, Z.

    2003-01-01

    The anisotropic magnetoresistance (AMR) in permalloy Ni 81 Fe 19 film deposited on a 1.2 nm Co 33 Cr 67 buffer layer was significantly enhanced. The high-resolution electron microscopy was used to study the microstructure of Ni 81 Fe 19 film with and without Co 33 Cr 67 buffer layer. It was found that Co 33 Cr 67 buffer layer can induce good (1 1 1) texture, while without Co 33 Cr 67 buffer layer, Ni 81 Fe 19 film show randomly oriented grain structure. The Δρ/ρ enhancement is attributed to the decrease in the resistivity ρ of the Ni 81 Fe 19 film due to the formation of the large (1 1 1) textured grains in Ni 81 Fe 19 film with Co 33 Cr 67 buffer layer. However, the surface roughness of substrate may limit the (1 1 1) textured grain size and induce additional grain boundaries in Ni 81 Fe 19 film with Co 33 Cr 67 buffer layer, limit the enhancement of the AMR effect

  7. High-resolution electron microscopy study of electron-irradiation-induced crystalline-to-amorphous transition in α-SiC single crystals

    International Nuclear Information System (INIS)

    Inui, H.; Mori, H.; Sakata, T.

    1992-01-01

    An electron-irradiation-induced crystalline-to-amorphous (CA) transition in α-SiC has been studied by high-resolution electron microscopy (HREM). The irradiation-produced damage structure was examined as a function of dose of electrons by taking high-resolution maps extending from the unirradiated crystalline region to the completely amorphized region. In the intermediate region between those two regions, that is in the CA transition region, the damage structure was essentially a mixture of crystalline and amorphous phases. The volume fraction of the amorphous phase was found to increase with increasing dose of electrons and no discrete crystalline-amorphous interface was observed in the CA transition region. These facts indicate the heterogeneous and gradual nature of the CA transition. In the transition region close to the unirradiated crystalline region, a sort of fragmentation of the crystal lattice was observed to occur, crystallites with slightly different orientations with respect to the parent crystal were formed owing to the strain around the dispersed local amorphous regions. In the transition region close to the amorphized region, these crystallites were reduced in size and were embedded in an amorphous matrix. This damage structure is the result of the increased volume fraction of the amorphous phase. In the completely amorphized region, no lattice fringes were recognized in the HREM images. The atomistic process of the CA transition is discussed on the basis of the present results and those from previous studies. (Author)

  8. Direct observations of the MOF (UiO-66) structure by transmission electron microscopy

    KAUST Repository

    Zhu, Liangkui

    2013-01-01

    As a demonstration of ab initio structure characterizations of nano metal organic framework (MOF) crystals by high resolution transmission electron microscopy (HRTEM) and electron diffraction tomography methods, a Zr-MOF (UiO-66) structure was determined and further confirmed by Rietveld refinements of powder X-ray diffraction. HRTEM gave direct imaging of the channels. © 2013 The Royal Society of Chemistry.

  9. High-resolution electron spectroscopy of lanthanide (Ce, Pr, and Nd) complexes of cyclooctatetraene: the role of 4f electrons.

    Science.gov (United States)

    Kumari, Sudesh; Roudjane, Mourad; Hewage, Dilrukshi; Liu, Yang; Yang, Dong-Sheng

    2013-04-28

    Cerium, praseodymium, and neodymium complexes of 1,3,5,7-cyclooctatetraene (COT) complexes were produced in a laser-vaporization metal cluster source and studied by pulsed-field ionization zero electron kinetic energy spectroscopy and quantum chemical calculations. The computations included the second-order Møller-Plesset perturbation theory, the coupled cluster method with single, double, and perturbative triple excitations, and the state-average complete active space self-consistent field method. The spectrum of each complex exhibits multiple band systems and is assigned to ionization of several low-energy electronic states of the neutral complex. This observation is different from previous studies of M(COT) (M = Sc, Y, La, and Gd), for which a single band system was observed. The presence of the multiple low-energy electronic states is caused by the splitting of the partially filled lanthanide 4f orbitals in the ligand field, and the number of the low-energy states increases rapidly with increasing number of the metal 4f electrons. On the other hand, the 4f electrons have a small effect on the geometries and vibrational frequencies of these lanthanide complexes.

  10. Electronic excitation of furfural as probed by high-resolution vacuum ultraviolet spectroscopy, electron energy loss spectroscopy, and ab initio calculations

    Science.gov (United States)

    Ferreira da Silva, F.; Lange, E.; Limão-Vieira, P.; Jones, N. C.; Hoffmann, S. V.; Hubin-Franskin, M.-J.; Delwiche, J.; Brunger, M. J.; Neves, R. F. C.; Lopes, M. C. A.; de Oliveira, E. M.; da Costa, R. F.; Varella, M. T. do N.; Bettega, M. H. F.; Blanco, F.; García, G.; Lima, M. A. P.; Jones, D. B.

    2015-10-01

    The electronic spectroscopy of isolated furfural (2-furaldehyde) in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 3.5-10.8 eV energy-range, with absolute cross section measurements derived. Electron energy loss spectra are also measured over a range of kinematical conditions. Those energy loss spectra are used to derive differential cross sections and in turn generalised oscillator strengths. These experiments are supported by ab initio calculations in order to assign the excited states of the neutral molecule. The good agreement between the theoretical results and the measurements allows us to provide the first quantitative assignment of the electronic state spectroscopy of furfural over an extended energy range.

  11. Electronic excitation of furfural as probed by high-resolution vacuum ultraviolet spectroscopy, electron energy loss spectroscopy, and ab initio calculations

    International Nuclear Information System (INIS)

    Ferreira da Silva, F.; Lange, E.; Limão-Vieira, P.; Jones, N. C.; Hoffmann, S. V.; Hubin-Franskin, M.-J.; Delwiche, J.; Brunger, M. J.

    2015-01-01

    The electronic spectroscopy of isolated furfural (2-furaldehyde) in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 3.5–10.8 eV energy-range, with absolute cross section measurements derived. Electron energy loss spectra are also measured over a range of kinematical conditions. Those energy loss spectra are used to derive differential cross sections and in turn generalised oscillator strengths. These experiments are supported by ab initio calculations in order to assign the excited states of the neutral molecule. The good agreement between the theoretical results and the measurements allows us to provide the first quantitative assignment of the electronic state spectroscopy of furfural over an extended energy range

  12. Electronic excitation of furfural as probed by high-resolution vacuum ultraviolet spectroscopy, electron energy loss spectroscopy, and ab initio calculations

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira da Silva, F.; Lange, E. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Limão-Vieira, P., E-mail: plimaovieira@fct.unl.pt, E-mail: michael.brunger@flinders.edu.au, E-mail: maplima@ifi.unicamp.br [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Jones, N. C.; Hoffmann, S. V. [ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade, DK-8000 Århus C (Denmark); Hubin-Franskin, M.-J.; Delwiche, J. [Départment de Chimie, Institut de Chimie-Bât. B6C, Université de Liège, B-4000 Liège 1 (Belgium); Brunger, M. J., E-mail: plimaovieira@fct.unl.pt, E-mail: michael.brunger@flinders.edu.au, E-mail: maplima@ifi.unicamp.br [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); and others

    2015-10-14

    The electronic spectroscopy of isolated furfural (2-furaldehyde) in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 3.5–10.8 eV energy-range, with absolute cross section measurements derived. Electron energy loss spectra are also measured over a range of kinematical conditions. Those energy loss spectra are used to derive differential cross sections and in turn generalised oscillator strengths. These experiments are supported by ab initio calculations in order to assign the excited states of the neutral molecule. The good agreement between the theoretical results and the measurements allows us to provide the first quantitative assignment of the electronic state spectroscopy of furfural over an extended energy range.

  13. Inner-Shell Excitations of 2p Electrons of Argon Investigated by Fast Electron Impact with High Resolution

    International Nuclear Information System (INIS)

    Ren Lin-Mao; Wang You-Yan; Li Dong-Dong; Yuan Zhen-Sheng; Zhu Lin-Fan

    2011-01-01

    Electron energy loss spectra of inner-shell excitations of 2p electrons of argon are measured at an incident electron energy of 2500 eV and scattering angles of 0° and 4°. The dipole-forbidden transitions of 2p −1 3/2 4p and 2p −1 3/2 5p are observed in the measured spectra and assigned based on the calculations of the Cowan code. The positions and line widths for the excitations of 2p −1 3/2 nl and 2p −1 1/2 nl (n ≤ 5) of argon are determined. The present results show that the line widths of the electric quadrupole transitions of 2p −1 3/2 4p[5/2 + 3/2] 2 and the electric monopole one of 2p −1 3/2 4p[1/2] 0 are less than those of the dipole-allowed transitions. (atomic and molecular physics)

  14. Calibration of the OHREX high-resolution imaging crystal spectrometer at the Livermore electron beam ion traps

    Energy Technology Data Exchange (ETDEWEB)

    Hell, N. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Dr. Remeis-Sternwarte and ECAP, Universität Erlangen-Nürnberg, Bamberg 96049 (Germany); Beiersdorfer, P.; Magee, E. W.; Brown, G. V. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2016-11-15

    We report the calibration of the Orion High-Resolution X-ray (OHREX) imaging crystal spectrometer at the EBIT-I electron beam ion trap at Livermore. Two such instruments, dubbed OHREX-1 and OHREX-2, are fielded for plasma diagnostics at the Orion laser facility in the United Kingdom. The OHREX spectrometer can simultaneously house two spherically bent crystals with a radius of curvature of r = 67.2 cm. The focusing properties of the spectrometer allow both for larger distance to the source due to the increase in collected light and for observation of extended sources. OHREX is designed to cover a 2.5°–3° spectral range at Bragg angles around 51.3°. The typically high resolving powers at these large Bragg angles are ideally suited for line shape diagnostics. For instance, the nominal resolving power of the instrument (>10 000) is much higher than the effective resolving power associated with the Doppler broadening due to the temperature of the trapped ions in EBIT-I. The effective resolving power is only around 3000 at typical EBIT-I conditions, which nevertheless is sufficient to set up and test the instrument’s spectral characteristics. We have calibrated the spectral range for a number of crystals using well known reference lines in the first and second order and derived the ion temperatures from these lines. We have also made use of the 50 μm size of the EBIT-I source width to characterize the spatial focusing of the spectrometer.

  15. Transmission environmental scanning electron microscope with scintillation gaseous detection device

    International Nuclear Information System (INIS)

    Danilatos, Gerasimos; Kollia, Mary; Dracopoulos, Vassileios

    2015-01-01

    A transmission environmental scanning electron microscope with use of a scintillation gaseous detection device has been implemented. This corresponds to a transmission scanning electron microscope but with addition of a gaseous environment acting both as environmental and detection medium. A commercial type of low vacuum machine has been employed together with appropriate modifications to the detection configuration. This involves controlled screening of various emitted signals in conjunction with a scintillation gaseous detection device already provided with the machine for regular surface imaging. Dark field and bright field imaging has been obtained along with other detection conditions. With a progressive series of modifications and tests, the theory and practice of a novel type of microscopy is briefly shown now ushering further significant improvements and developments in electron microscopy as a whole. - Highlights: • Novel scanning transmission electron microscopy (STEM) with an environmental scanning electron microscope (ESEM) called TESEM. • Use of the gaseous detection device (GDD) in scintillation mode that allows high resolution bright and dark field imaging in the TESEM. • Novel approach towards a unification of both vacuum and environmental conditions in both bulk/surface and transmission mode of electron microscopy

  16. Transmission electron microscopy investigation of Bi-2223/Ag tapes

    DEFF Research Database (Denmark)

    Andersen, L.G.; Bals, S.; Tendeloo, G. Van

    2001-01-01

    during the tape processing, (3) a study of the grain boundaries on an atomic scale, including intergrowth investigations. Tapes with different process parameters have been compared with respect to the microstructure. A fully processed tape has on the average 50% thicker Bi-2223 grains than a tape after......The microstructure of (Bi,Pb)(2)Sr2Ca2CuOx (Bi-2223) tapes has been investigated by means of transmission electron microscopy (TEM) and high-resolution TEM. The emphasis has been placed on: (1) an examination of the grain morphology and size, (2) grain and colony boundary angles, which are formed...

  17. Evaluation of gas chromatography – electron ionization – full scan high resolution Orbitrap mass spectrometry for pesticide residue analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mol, Hans G.J., E-mail: hans.mol@wur.nl; Tienstra, Marc; Zomer, Paul

    2016-09-07

    Gas chromatography with electron ionization and full scan high resolution mass spectrometry with an Orbitrap mass analyzer (GC-EI-full scan Orbitrap HRMS) was evaluated for residue analysis. Pesticides in fruit and vegetables were taken as an example application. The relevant aspects for GC-MS based residue analysis, including the resolving power (15,000 to 120,000 FWHM at m/z 200), scan rate, dynamic range, selectivity, sensitivity, analyte identification, and utility of existing EI-libraries, are assessed and discussed in detail. The optimum acquisition conditions in full scan mode (m/z 50–500) were a resolving power of 60,000 and an automatic-gain-control target value of 3E6. These conditions provided (i) an optimum mass accuracy: within 2 ppm over a wide concentration range, with/without matrix, enabling the use of ±5 ppm mass extraction windows (ii) adequate scan speed: minimum 12 scans/peak, (iii) an intra-scan dynamic range sufficient to achieve LOD/LOQs ≤0.5 pg in fruit/vegetable matrices (corresponding to ≤0.5 μg kg{sup −1}) for most pesticides. EI-Orbitrap spectra were consistent over a very wide concentration range (5 orders) with good match values against NIST (EI-quadrupole) spectra. The applicability for quantitative residue analysis was verified by validation of 54 pesticides in three matrices (tomato, leek, orange) at 10 and 50 μg/kg. The method involved a QuEChERS-based extraction with a solvent switch into iso-octane, and 1 μL hot splitless injection into the GC-HRMS system. A recovery between 70 and 120% and a repeatability RSD <10% was obtained in most cases. Linearity was demonstrated for the range ≤5–250 μg kg{sup −1}. The pesticides could be identified according to the applicable EU criteria for GC-HRMS (SANTE/11945/2015). GC-EI-full scan Orbitrap HRMS was found to be highly suited for quantitative pesticide residue analysis. The potential of qualitative screening to extend the scope makes it an attractive

  18. Evaluation of gas chromatography – electron ionization – full scan high resolution Orbitrap mass spectrometry for pesticide residue analysis

    International Nuclear Information System (INIS)

    Mol, Hans G.J.; Tienstra, Marc; Zomer, Paul

    2016-01-01

    Gas chromatography with electron ionization and full scan high resolution mass spectrometry with an Orbitrap mass analyzer (GC-EI-full scan Orbitrap HRMS) was evaluated for residue analysis. Pesticides in fruit and vegetables were taken as an example application. The relevant aspects for GC-MS based residue analysis, including the resolving power (15,000 to 120,000 FWHM at m/z 200), scan rate, dynamic range, selectivity, sensitivity, analyte identification, and utility of existing EI-libraries, are assessed and discussed in detail. The optimum acquisition conditions in full scan mode (m/z 50–500) were a resolving power of 60,000 and an automatic-gain-control target value of 3E6. These conditions provided (i) an optimum mass accuracy: within 2 ppm over a wide concentration range, with/without matrix, enabling the use of ±5 ppm mass extraction windows (ii) adequate scan speed: minimum 12 scans/peak, (iii) an intra-scan dynamic range sufficient to achieve LOD/LOQs ≤0.5 pg in fruit/vegetable matrices (corresponding to ≤0.5 μg kg"−"1) for most pesticides. EI-Orbitrap spectra were consistent over a very wide concentration range (5 orders) with good match values against NIST (EI-quadrupole) spectra. The applicability for quantitative residue analysis was verified by validation of 54 pesticides in three matrices (tomato, leek, orange) at 10 and 50 μg/kg. The method involved a QuEChERS-based extraction with a solvent switch into iso-octane, and 1 μL hot splitless injection into the GC-HRMS system. A recovery between 70 and 120% and a repeatability RSD <10% was obtained in most cases. Linearity was demonstrated for the range ≤5–250 μg kg"−"1. The pesticides could be identified according to the applicable EU criteria for GC-HRMS (SANTE/11945/2015). GC-EI-full scan Orbitrap HRMS was found to be highly suited for quantitative pesticide residue analysis. The potential of qualitative screening to extend the scope makes it an attractive alternative to

  19. High Resolution Typing by Whole Genome Mapping Enables Discrimination of LA-MRSA (CC398) Strains and Identification of Transmission Events

    Science.gov (United States)

    Bosch, Thijs; Verkade, Erwin; van Luit, Martijn; Pot, Bruno; Vauterin, Paul; Burggrave, Ronald; Savelkoul, Paul; Kluytmans, Jan; Schouls, Leo

    2013-01-01

    After its emergence in 2003, a livestock-associated (LA-)MRSA clade (CC398) has caused an impressive increase in the number of isolates submitted for the Dutch national MRSA surveillance and now comprises 40% of all isolates. The currently used molecular typing techniques have limited discriminatory power for this MRSA clade, which hampers studies on the origin and transmission routes. Recently, a new molecular analysis technique named whole genome mapping was introduced. This method creates high-resolution, ordered whole genome restriction maps that may have potential for strain typing. In this study, we assessed and validated the capability of whole genome mapping to differentiate LA-MRSA isolates. Multiple validation experiments showed that whole genome mapping produced highly reproducible results. Assessment of the technique on two well-documented MRSA outbreaks showed that whole genome mapping was able to confirm one outbreak, but revealed major differences between the maps of a second, indicating that not all isolates belonged to this outbreak. Whole genome mapping of LA-MRSA isolates that were epidemiologically unlinked provided a much higher discriminatory power than spa-typing or MLVA. In contrast, maps created from LA-MRSA isolates obtained during a proven LA-MRSA outbreak were nearly indistinguishable showing that transmission of LA-MRSA can be detected by whole genome mapping. Finally, whole genome maps of LA-MRSA isolates originating from two unrelated veterinarians and their household members showed that veterinarians may carry and transmit different LA-MRSA strains at the same time. No such conclusions could be drawn based spa-typing and MLVA. Although PFGE seems to be suitable for molecular typing of LA-MRSA, WGM provides a much higher discriminatory power. Furthermore, whole genome mapping can provide a comparison with other maps within 2 days after the bacterial culture is received, making it suitable to investigate transmission events and

  20. Transmission electron microscopy: direct observation of crystal structure in refractory ceramics.

    Science.gov (United States)

    Shaw, T M; Thomas, G

    1978-11-10

    Using high-resolution multibeam interference techniques in the transmission electron microscope, images have been obtained that make possible a real-space structure analysis of a beryllium-silicon-nitrogen compound. The results illustrate the usefulness of lattice imaging in the analysis of local crystal structure in these technologically promising ceramic materials.

  1. Medical high-resolution image sharing and electronic whiteboard system: A pure-web-based system for accessing and discussing lossless original images in telemedicine.

    Science.gov (United States)

    Qiao, Liang; Li, Ying; Chen, Xin; Yang, Sheng; Gao, Peng; Liu, Hongjun; Feng, Zhengquan; Nian, Yongjian; Qiu, Mingguo

    2015-09-01

    There are various medical image sharing and electronic whiteboard systems available for diagnosis and discussion purposes. However, most of these systems ask clients to install special software tools or web plug-ins to support whiteboard discussion, special medical image format, and customized decoding algorithm of data transmission of HRIs (high-resolution images). This limits the accessibility of the software running on different devices and operating systems. In this paper, we propose a solution based on pure web pages for medical HRIs lossless sharing and e-whiteboard discussion, and have set up a medical HRI sharing and e-whiteboard system, which has four-layered design: (1) HRIs access layer: we improved an tile-pyramid model named unbalanced ratio pyramid structure (URPS), to rapidly share lossless HRIs and to adapt to the reading habits of users; (2) format conversion layer: we designed a format conversion engine (FCE) on server side to real time convert and cache DICOM tiles which clients requesting with window-level parameters, to make browsers compatible and keep response efficiency to server-client; (3) business logic layer: we built a XML behavior relationship storage structure to store and share users' behavior, to keep real time co-browsing and discussion between clients; (4) web-user-interface layer: AJAX technology and Raphael toolkit were used to combine HTML and JavaScript to build client RIA (rich Internet application), to meet clients' desktop-like interaction on any pure webpage. This system can be used to quickly browse lossless HRIs, and support discussing and co-browsing smoothly on any web browser in a diversified network environment. The proposal methods can provide a way to share HRIs safely, and may be used in the field of regional health, telemedicine and remote education at a low cost. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. A novel high-resolution multilocus sequence typing of Giardia intestinalis Assemblage A isolates reveals zoonotic transmission, clonal outbreaks and recombination.

    Science.gov (United States)

    Ankarklev, Johan; Lebbad, Marianne; Einarsson, Elin; Franzén, Oscar; Ahola, Harri; Troell, Karin; Svärd, Staffan G

    2018-06-01

    Molecular epidemiology and genotyping studies of the parasitic protozoan Giardia intestinalis have proven difficult due to multiple factors, such as low discriminatory power in the commonly used genotyping loci, which has hampered molecular analyses of outbreak sources, zoonotic transmission and virulence types. Here we have focused on assemblage A Giardia and developed a high-resolution assemblage-specific multilocus sequence typing (MLST) method. Analyses of sequenced G. intestinalis assemblage A genomes from different sub-assemblages identified a set of six genetic loci with high genetic variability. DNA samples from both humans (n = 44) and animals (n = 18) that harbored Giardia assemblage A infections, were PCR amplified (557-700 bp products) and sequenced at the six novel genetic loci. Bioinformatic analyses showed five to ten-fold higher levels of polymorphic sites than what was previously found among assemblage A samples using the classic genotyping loci. Phylogenetically, a division of two major clusters in assemblage A became apparent, separating samples of human and animal origin. A subset of human samples (n = 9) from a documented Giardia outbreak in a Swedish day-care center, showed full complementarity at nine genetic loci (the six new and the standard BG, TPI and GDH loci), strongly suggesting one source of infection. Furthermore, three samples of human origin displayed MLST profiles that were phylogenetically more closely related to MLST profiles from animal derived samples, suggesting zoonotic transmission. These new genotyping loci enabled us to detect events of recombination between different assemblage A isolates but also between assemblage A and E isolates. In summary, we present a novel and expanded MLST strategy with significantly improved sensitivity for molecular analyses of virulence types, zoonotic potential and source tracking for assemblage A Giardia. Copyright © 2018. Published by Elsevier B.V.

  3. High-Resolution Electron Energy Loss Studies of Oxygen, Hydrogen, Nitrogen, Nitric Oxide, and Nitrous Oxide Adsorption on Germanium Surfaces.

    Science.gov (United States)

    Entringer, Anthony G.

    The first high resolution electron energy loss spectroscopy (HREELS) studies of the oxidation and nitridation of germanium surfaces are reported. Both single crystal Ge(111) and disordered surfaces were studied. Surfaces were exposed to H, O_2, NO, N _2O, and N, after cleaning in ultra-high vacuum. The Ge surfaces were found to be non-reactive to molecular hydrogen (H_2) at room temperature. Exposure to atomic hydrogen (H) resulted hydrogen adsorption as demonstrated by the presence of Ge-H vibrational modes. The HREEL spectrum of the native oxide of Ge characteristic of nu -GeO_2 was obtained by heating the oxide to 200^circC. Three peaks were observed at 33, 62, and 106 meV for molecular oxygen (O_2) adsorbed on clean Ge(111) at room temperature. These peaks are indicative of dissociative bonding and a dominant Ge-O-Ge bridge structure. Subsequent hydrogen exposure resulted in a shift of the Ge-H stretch from its isolated value of 247 meV to 267 meV, indicative of a dominant +3 oxidation state. A high density of dangling bonds and defects and deeper oxygen penetration at the amorphous Ge surface result in a dilute bridge structure with a predominant +1 oxidation state for similar exposures. Molecules of N_2O decompose at the surfaces to desorbed N_2 molecules and chemisorbed oxygen atoms. In contrast, both oxygen and nitrogen are detected at the surfaces following exposure to NO molecules. Both NO and N_2O appear to dissociate and bond at the top surface layer. Molecular nitrogen (N_2) does not react with the Ge surfaces, however, a precursor Ge nitride is observed at room temperature following exposure to nitrogen atoms and ions. Removal of oxygen by heating of the NO-exposed surface to 550^circC enabled the identification of the Ge-N vibrational modes. These modes show a structure similar to that of germanium nitride. This spectrum is also identical to that of the N-exposed surface heated to 550^circC. Surface phonon modes of the narrow-gap semiconducting

  4. High resolution STEM of quantum dots and quantum wires

    DEFF Research Database (Denmark)

    Kadkhodazadeh, Shima

    2013-01-01

    This article reviews the application of high resolution scanning transmission electron microscopy (STEM) to semiconductor quantum dots (QDs) and quantum wires (QWRs). Different imaging and analytical techniques in STEM are introduced and key examples of their application to QDs and QWRs...

  5. High resolution, high speed ultrahigh vacuum microscopy

    International Nuclear Information System (INIS)

    Poppa, Helmut

    2004-01-01

    The history and future of transmission electron microscopy (TEM) is discussed as it refers to the eventual development of instruments and techniques applicable to the real time in situ investigation of surface processes with high resolution. To reach this objective, it was necessary to transform conventional high resolution instruments so that an ultrahigh vacuum (UHV) environment at the sample site was created, that access to the sample by various in situ sample modification procedures was provided, and that in situ sample exchanges with other integrated surface analytical systems became possible. Furthermore, high resolution image acquisition systems had to be developed to take advantage of the high speed imaging capabilities of projection imaging microscopes. These changes to conventional electron microscopy and its uses were slowly realized in a few international laboratories over a period of almost 40 years by a relatively small number of researchers crucially interested in advancing the state of the art of electron microscopy and its applications to diverse areas of interest; often concentrating on the nucleation, growth, and properties of thin films on well defined material surfaces. A part of this review is dedicated to the recognition of the major contributions to surface and thin film science by these pioneers. Finally, some of the important current developments in aberration corrected electron optics and eventual adaptations to in situ UHV microscopy are discussed. As a result of all the path breaking developments that have led to today's highly sophisticated UHV-TEM systems, integrated fundamental studies are now possible that combine many traditional surface science approaches. Combined investigations to date have involved in situ and ex situ surface microscopies such as scanning tunneling microscopy/atomic force microscopy, scanning Auger microscopy, and photoemission electron microscopy, and area-integrating techniques such as x-ray photoelectron

  6. New developments in transmission electron microscopy for nanotechnology

    International Nuclear Information System (INIS)

    Wang, Z.L.

    2003-01-01

    High-resolution transmission electron microscopy (HRTEM) is one of the most powerful tools used for characterizing nanomaterials, and it is indispensable for nanotechnology. This paper reviews some of the most recent developments in electron microscopy techniques for characterizing nanomaterials. The review covers the following areas: in-situ microscopy for studying dynamic shape transformation of nanocrystals; in-situ nanoscale property measurements on the mechanical, electrical and field emission properties of nanotubes/nanowires; environmental microscopy for direct observation of surface reactions; aberration-free angstrom-resolution imaging of light elements (such as oxygen and lithium); high-angle annular-dark-field scanning transmission electron microscopy (STEM); imaging of atom clusters with atomic resolution chemical information; electron holography of magnetic materials; and high-spatial resolution electron energy-loss spectroscopy (EELS) for nanoscale electronic and chemical analysis. It is demonstrated that the picometer-scale science provided by HRTEM is the foundation of nanometer-scale technology. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  7. Transmission Electron Microscopy Physics of Image Formation

    CERN Document Server

    Kohl, Helmut

    2008-01-01

    Transmission Electron Microscopy: Physics of Image Formation presents the theory of image and contrast formation, and the analytical modes in transmission electron microscopy. The principles of particle and wave optics of electrons are described. Electron-specimen interactions are discussed for evaluating the theory of scattering and phase contrast. Also discussed are the kinematical and dynamical theories of electron diffraction and their applications for crystal-structure analysis and imaging of lattices and their defects. X-ray microanalysis and electron energy-loss spectroscopy are treated as analytical methods. Specimen damage and contamination by electron irradiation limits the resolution for biological and some inorganic specimens. This fifth edition includes discussion of recent progress, especially in the area of aberration correction and energy filtering; moreover, the topics introduced in the fourth edition have been updated. Transmission Electron Microscopy: Physics of Image Formation is written f...

  8. Design and construction of a high-stability, low-noise power supply for use with high-resolution electron energy loss spectrometers

    International Nuclear Information System (INIS)

    Katz, J.E.; Davies, P.W.; Crowell, J.E.; Somorjai, G.A.

    1982-01-01

    The design and construction of a high-stability, low-noise power supply which provides potentials for the lens and analyzer elements of a 127 0 Ehrhardt-type high-resolution electron energy loss spectrometer (HREELS) is described. The supply incorporates a filament emission-control circuit and facilities for measuring electron beam current at each spectrometer element, thus facilitating optimal tuning of the spectrometer. Spectra obtained using this supply are shown to have a four-fold improvement in signal-to-noise ratio and a higher resolution of the vibrational loss features when compared with spectra taken using a previously existing supply based on passive potential divider networks

  9. High-resolution inelastic electron scattering on 208Pb at 50 and 63.5 MeV and fragmentation of the magnetic quadrupole strength

    International Nuclear Information System (INIS)

    Knuepfer, W.; Frey, R.; Richter, A.; Schwierczinski, A.; Spamer, E.; Titze, O.

    1977-12-01

    High-resolution inelastic electron scattering (FWHM approximately equal to 33 keV) with 50 MeV and 63.5 MeV electrons on 208 Pb has been used to study magnetic excitations between Esub(x) = 6 MeV and 8 MeV. Angular distributions were analyzed in terms of the DWBA with RPA wave functions. Eight Isup(π) = 2- states carrying a total strength ΣB(M2) = 8500 μ 2 sub(K) fm 2 have been found. The strong fragmentation is in qualitative agreement with theoretical predictions. (orig.) [de

  10. Transmission electron microscope CCD camera

    Science.gov (United States)

    Downing, Kenneth H.

    1999-01-01

    In order to improve the performance of a CCD camera on a high voltage electron microscope, an electron decelerator is inserted between the microscope column and the CCD. This arrangement optimizes the interaction of the electron beam with the scintillator of the CCD camera while retaining optimization of the microscope optics and of the interaction of the beam with the specimen. Changing the electron beam energy between the specimen and camera allows both to be optimized.

  11. Transmission electron microscopy physics of image formation and microanalysis

    CERN Document Server

    Reimer, Ludwig

    1984-01-01

    The aim of this book is to outline the physics of image formation, electron­ specimen interactions and image interpretation in transmission electron mic­ roscopy. The book evolved from lectures delivered at the University of Munster and is a revised version of the first part of my earlier book Elek­ tronenmikroskopische Untersuchungs- und Priiparationsmethoden, omitting the part which describes specimen-preparation methods. In the introductory chapter, the different types of electron microscope are compared, the various electron-specimen interactions and their applications are summarized and the most important aspects of high-resolution, analytical and high-voltage electron microscopy are discussed. The optics of electron lenses is discussed in Chapter 2 in order to bring out electron-lens properties that are important for an understanding of the function of an electron microscope. In Chapter 3, the wave optics of elec­ trons and the phase shifts by electrostatic and magnetic fields are introduced; Fresne...

  12. Characterization of strained semiconductor structures using transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Oezdoel, Vasfi Burak

    2011-08-15

    Today's state-of-the-art semiconductor electronic devices utilize the charge transport within very small volumes of the active device regions. The structural, chemical and optical material properties in these small dimensions can critically affect the performance of these devices. The present thesis is focused on the nanometer scale characterization of the strain state in semiconductor structures using transmission electron microscopy (TEM). Although high-resolution TEM has shown to provide the required accuracy at the nanometer scale, optimization of imaging conditions is necessary for accurate strain measurements. An alternative HRTEM method based on strain mapping on complex-valued exit face wave functions is developed to reduce the artifacts arising from objective lens aberrations. However, a much larger field of view is crucial for mapping strain in the active regions of complex structures like latest generation metal-oxide-semiconductor field-effect transistors (MOSFETs). To overcome this, a complementary approach based on electron holography is proposed. The technique relies on the reconstruction of the phase shifts in the diffracted electron beams from a focal series of dark-field images using recently developed exit-face wave function reconstruction algorithm. Combining high spatial resolution, better than 1 nm, with a field of view of about 1 {mu}m in each dimension, simultaneous strain measurements on the array of MOSFETs are possible. Owing to the much lower electron doses used in holography experiments when compared to conventional quantitative methods, the proposed approach allows to map compositional distribution in electron beam sensitive materials such as InGaN heterostructures without alteration of the original morphology and chemical composition. Moreover, dark-field holography experiments can be performed on thicker specimens than the ones required for high-resolution TEM, which in turn reduces the thin foil relaxation. (orig.)

  13. Atomic-resolution transmission electron microscopy of electron beam–sensitive crystalline materials

    Science.gov (United States)

    Zhang, Daliang; Zhu, Yihan; Liu, Lingmei; Ying, Xiangrong; Hsiung, Chia-En; Sougrat, Rachid; Li, Kun; Han, Yu

    2018-02-01

    High-resolution imaging of electron beam–sensitive materials is one of the most difficult applications of transmission electron microscopy (TEM). The challenges are manifold, including the acquisition of images with extremely low beam doses, the time-constrained search for crystal zone axes, the precise image alignment, and the accurate determination of the defocus value. We develop a suite of methods to fulfill these requirements and acquire atomic-resolution TEM images of several metal organic frameworks that are generally recognized as highly sensitive to electron beams. The high image resolution allows us to identify individual metal atomic columns, various types of surface termination, and benzene rings in the organic linkers. We also apply our methods to other electron beam–sensitive materials, including the organic-inorganic hybrid perovskite CH3NH3PbBr3.

  14. Atomic-resolution transmission electron microscopy of electron beam–sensitive crystalline materials

    KAUST Repository

    Zhang, Daliang

    2018-01-18

    High-resolution imaging of electron beam-sensitive materials is one of the most difficult applications of transmission electron microscopy (TEM). The challenges are manifold, including the acquisition of images with extremely low beam doses, the time-constrained search for crystal zone axes, the precise image alignment, and the accurate determination of the defocus value. We develop a suite of methods to fulfill these requirements and acquire atomic-resolution TEM images of several metal organic frameworks that are generally recognized as highly sensitive to electron beams. The high image resolution allows us to identify individual metal atomic columns, various types of surface termination, and benzene rings in the organic linkers. We also apply our methods to other electron beam–sensitive materials, including the organic-inorganic hybrid perovskite CH3NH3PbBr3.

  15. Quantitative measurement of mean inner potential and specimen thickness from high-resolution off-axis electron holograms of ultra-thin layered WSe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, Florian, E-mail: f.winkler@fz-juelich.de [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, D-52425 Jülich (Germany); Peter Grünberg Institute 5 (PGI-5), Forschungszentrum Jülich, D-52425 Jülich (Germany); Tavabi, Amir H. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, D-52425 Jülich (Germany); Peter Grünberg Institute 5 (PGI-5), Forschungszentrum Jülich, D-52425 Jülich (Germany); Barthel, Juri [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, D-52425 Jülich (Germany); Gemeinschaftslabor für Elektronenmikroskopie (GFE), RWTH Aachen University, D-52074 Aachen (Germany); Duchamp, Martial [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, D-52425 Jülich (Germany); Peter Grünberg Institute 5 (PGI-5), Forschungszentrum Jülich, D-52425 Jülich (Germany); Yucelen, Emrah [FEI Company, Achtseweg Noord 5, Eindhoven 5600 KA (Netherlands); Borghardt, Sven; Kardynal, Beata E. [Peter Grünberg Institute 9 (PGI-9), Forschungszentrum Jülich, D-52425 Jülich (Germany); and others

    2017-07-15

    The phase and amplitude of the electron wavefunction that has passed through ultra-thin flakes of WSe{sub 2} is measured from high-resolution off-axis electron holograms. Both the experimental measurements and corresponding computer simulations are used to show that, as a result of dynamical diffraction, the spatially averaged phase does not increase linearly with specimen thickness close to an [001] zone axis orientation even when the specimen has a thickness of only a few layers. It is then not possible to infer the local specimen thickness of the WSe{sub 2} from either the phase or the amplitude alone. Instead, we show that the combined analysis of phase and amplitude from experimental measurements and simulations allows an accurate determination of the local specimen thickness. The relationship between phase and projected potential is shown to be approximately linear for extremely thin specimens that are tilted by several degrees in certain directions from the [001] zone axis. A knowledge of the specimen thickness then allows the electrostatic potential to be determined from the measured phase. By using this combined approach, we determine a value for the mean inner potential of WSe{sub 2} of 18.9±0.8 V, which is 12% lower than the value calculated from neutral atom scattering factors. - Highlights: • Quantitative analysis of high resolution electron holograms of WSe{sub 2}. • Local specimen thickness determination and estimation of tilt angle. • Mean inner potential evaluation of WSe2 avoiding dynamical diffraction.

  16. All-inkjet-printed flexible electronics fabrication on a polymer substrate by low-temperature high-resolution selective laser sintering of metal nanoparticles

    International Nuclear Information System (INIS)

    Ko, Seung H; Pan Heng; Grigoropoulos, Costas P; Luscombe, Christine K; Frechet, Jean M J; Poulikakos, Dimos

    2007-01-01

    All-printed electronics is the key technology to ultra-low-cost, large-area electronics. As a critical step in this direction, we demonstrate that laser sintering of inkjet-printed metal nanoparticles enables low-temperature metal deposition as well as high-resolution patterning to overcome the resolution limitation of the current inkjet direct writing processes. To demonstrate this process combined with the implementation of air-stable carboxylate-functionalized polythiophenes, high-resolution organic transistors were fabricated in ambient pressure and room temperature without utilizing any photolithographic steps or requiring a vacuum deposition process. Local thermal control of the laser sintering process could minimize the heat-affected zone and the thermal damage to the substrate and further enhance the resolution of the process. This local nanoparticle deposition and energy coupling enable an environmentally friendly and cost-effective process as well as a low-temperature manufacturing sequence to realize large-area, flexible electronics on polymer substrates

  17. Development of AMS high resolution injector system

    International Nuclear Information System (INIS)

    Bao Yiwen; Guan Xialing; Hu Yueming

    2008-01-01

    The Beijing HI-13 tandem accelerator AMS high resolution injector system was developed. The high resolution energy achromatic system consists of an electrostatic analyzer and a magnetic analyzer, which mass resolution can reach 600 and transmission is better than 80%. (authors)

  18. A silicon microstrip detector in a magnetic spectrometer for high-resolution electron scattering experiments at the S-DALINAC

    International Nuclear Information System (INIS)

    Lenhardt, A.W.; Bonnes, U.; Burda, O.; Neumann-Cosel, P. von; Platz, M.; Richter, A.; Watzlawik, S.

    2006-01-01

    A silicon microstrip detector was developed as focal plane detector of the 169.7 deg. magic angle double-focussing spectrometer at the superconducting Darmstadt electron linear accelerator (S-DALINAC). It allows experiments with minimum ionizing electrons at data rates up to 100 kHz, utilizing the maximum resolution of the spectrometer achievable in dispersion-matching mode

  19. Design of a transmission electron positron microscope

    International Nuclear Information System (INIS)

    Doyama, Masao; Inoue, M.; Kogure, Y.; Hayashi, Y.; Yoshii, T.; Kurihara, T.; Tsuno, K.

    2003-01-01

    This paper reports the plans and design of positron-electron microscopes being built at KEK (High Energy Accelerator Research Organization), Tsukuba, Japan. A used electron microscope is altered. The kinetic energies of positrons produced by accelerators or by nuclear decays are not a unique value but show a spread over in a wide range. Positron beam is guided to a transmission electron microscope (JEM100SX). Positrons are moderated by a tungsten foil, are accelerated and are focused on a nickel sheet. The monochromatic focused beam is injected into an electron microscope. The focusing and aberration of positrons are the same as electrons in a magnetic system which are used in commercial electron microscopes. Imaging plates are used to record positron images for the transmission electron microscope. (author)

  20. Intense energetic electron flux enhancements in Mercury's magnetosphere: An integrated view with high-resolution observations from MESSENGER.

    Science.gov (United States)

    Baker, Daniel N; Dewey, Ryan M; Lawrence, David J; Goldsten, John O; Peplowski, Patrick N; Korth, Haje; Slavin, James A; Krimigis, Stamatios M; Anderson, Brian J; Ho, George C; McNutt, Ralph L; Raines, Jim M; Schriver, David; Solomon, Sean C

    2016-03-01

    The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission to Mercury has provided a wealth of new data about energetic particle phenomena. With observations from MESSENGER's Energetic Particle Spectrometer, as well as data arising from energetic electrons recorded by the X-Ray Spectrometer and Gamma-Ray and Neutron Spectrometer (GRNS) instruments, recent work greatly extends our record of the acceleration, transport, and loss of energetic electrons at Mercury. The combined data sets include measurements from a few keV up to several hundred keV in electron kinetic energy and have permitted relatively good spatial and temporal resolution for many events. We focus here on the detailed nature of energetic electron bursts measured by the GRNS system, and we place these events in the context of solar wind and magnetospheric forcing at Mercury. Our examination of data at high temporal resolution (10 ms) during the period March 2013 through October 2014 supports strongly the view that energetic electrons are accelerated in the near-tail region of Mercury's magnetosphere and are subsequently "injected" onto closed magnetic field lines on the planetary nightside. The electrons populate the plasma sheet and drift rapidly eastward toward the dawn and prenoon sectors, at times executing multiple complete drifts around the planet to form "quasi-trapped" populations.

  1. Visualization of bacterial polysaccharides by scanning transmission electron microscopy.

    Science.gov (United States)

    Wolanski, B S; McAleer, W J; Hilleman, M R

    1983-04-01

    Highly purified capsular polysaccharides of Neisseria meningitidis groups A, B, and C have been visualized by high resolution Scanning Transmission Electron Microscopy (STEM). Spheroidal macromolecules approximately 200 A in diameter are characteristic of the Meningococcus A and C polysaccharides whereas filaments that are 400-600 A in length are found in Meningococcus B polysaccharide preparations. Filaments are occasionally found associated with the spheroidal Meningococcus A and C polysaccharides and it is proposed that these structures are composed of a long (1-4 microns) filament or filaments that are arranged in spheroidal molecules or micelles of high molecular weight. The Meningococcus B polysaccharide, by contrast, is a short flexuous filament or strand of relatively low molecular weight. A relationship between morphology and antigenicity is proposed.

  2. Helium ion microscopy and ultra-high-resolution scanning electron microscopy analysis of membrane-extracted cells reveals novel characteristics of the cytoskeleton of Giardia intestinalis.

    Science.gov (United States)

    Gadelha, Ana Paula Rocha; Benchimol, Marlene; de Souza, Wanderley

    2015-06-01

    Giardia intestinalis presents a complex microtubular cytoskeleton formed by specialized structures, such as the adhesive disk, four pairs of flagella, the funis and the median body. The ultrastructural organization of the Giardia cytoskeleton has been analyzed using different microscopic techniques, including high-resolution scanning electron microscopy. Recent advances in scanning microscopy technology have opened a new venue for the characterization of cellular structures and include scanning probe microscopy techniques such as ultra-high-resolution scanning electron microscopy (UHRSEM) and helium ion microscopy (HIM). Here, we studied the organization of the cytoskeleton of G. intestinalis trophozoites using UHRSEM and HIM in membrane-extracted cells. The results revealed a number of new cytoskeletal elements associated with the lateral crest and the dorsal surface of the parasite. The fine structure of the banded collar was also observed. The marginal plates were seen linked to a network of filaments, which were continuous with filaments parallel to the main cell axis. Cytoplasmic filaments that supported the internal structures were seen by the first time. Using anti-actin antibody, we observed a labeling in these filamentous structures. Taken together, these data revealed new surface characteristics of the cytoskeleton of G. intestinalis and may contribute to an improved understanding of the structural organization of trophozoites. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Structural Fingerprinting of Nanocrystals in the Transmission Electron Microscope

    Science.gov (United States)

    Rouvimov, Sergei; Plachinda, Pavel; Moeck, Peter

    2010-03-01

    Three novel strategies for the structurally identification of nanocrystals in a transmission electron microscope are presented. Either a single high-resolution transmission electron microscopy image [1] or a single precession electron diffractogram (PED) [2] may be employed. PEDs from fine-grained crystal powders may also be utilized. Automation of the former two strategies is in progress and shall lead to statistically significant results on ensembles of nanocrystals. Open-access databases such as the Crystallography Open Database which provides more than 81,500 crystal structure data sets [3] or its mainly inorganic and educational subsets [4] may be utilized. [1] http://www.scientificjournals.org/journals 2007/j/of/dissertation.htm [2] P. Moeck and S. Rouvimov, in: {Drugs and the Pharmaceutical Sciences}, Vol. 191, 2009, 270-313 [3] http://cod.ibt.lt, http://www.crystallography.net, http://cod.ensicaen.fr, http://nanocrystallography.org, http://nanocrystallography.net, http://journals.iucr.org/j/issues/2009/04/00/kk5039/kk5039.pdf [4] http://nanocrystallography.research.pdx.edu/CIF-searchable

  4. Transmission Electron Microscopy of Itokawa Regolith Grains

    Science.gov (United States)

    Keller, Lindsay P.; Berger, E. L.

    2013-01-01

    Introduction: In a remarkable engineering achievement, the JAXA space agency successfully recovered the Hayabusa space-craft in June 2010, following a non-optimal encounter and sur-face sampling mission to asteroid 25143 Itokawa. These are the first direct samples ever obtained and returned from the surface of an asteroid. The Hayabusa samples thus present a special op-portunity to directly investigate the evolution of asteroidal sur-faces, from the development of the regolith to the study of the effects of space weathering. Here we report on our preliminary TEM measurements on two Itokawa samples. Methods: We were allocated particles RA-QD02-0125 and RA-QD02-0211. Both particles were embedded in low viscosity epoxy and thin sections were prepared using ultramicrotomy. High resolution images and electron diffraction data were ob-tained using a JEOL 2500SE 200 kV field-emission scanning-transmission electron microscope. Quantitative maps and anal-yses were obtained using a Thermo thin-window energy-dispersive x-ray (EDX) spectrometer. Results: Both particles are olivine-rich (Fo70) with µm-sized inclusions of FeS and have microstructurally complex rims. Par-ticle RA-QD02-0125 is rounded and has numerous sub-µm grains attached to its surface including FeS, albite, olivine, and rare melt droplets. Solar flare tracks have not been observed, but the particle is surrounded by a continuous 50 nm thick, stuctur-ally disordered rim that is compositionally similar to the core of the grain. One of the surface adhering grains is pyrrhotite show-ing a S-depleted rim (8-10 nm thick) with nanophase Fe metal grains (<5 nm) decorating the outermost surface. The pyrrhotite displays a complex superstructure in its core that is absent in the S-depleted rim. Particle RA-QD02-0211 contains solar flare particle tracks (2x109 cm-2) and shows a structurally disordered rim 100 nm thick. The track density corresponds to a surface exposure of 103-104 years based on the track production rate

  5. High Resolution Elevation Contours

    Data.gov (United States)

    Minnesota Department of Natural Resources — This dataset contains contours generated from high resolution data sources such as LiDAR. Generally speaking this data is 2 foot or less contour interval.

  6. High resolution scanning electron microscopy of rabbit corneal endothelium to show effects of UV-visible irradiation in the presence of chlorpromazine

    International Nuclear Information System (INIS)

    Lea, P.J.; Hollenberg, M.J.; Menon, I.A.; Temkin, R.J.; Persad, S.D.; Basu, P.K.

    1989-01-01

    The ultrastructure of rabbit cornea endothelial cells was examined by scanning electron microscopy (SEM) in freeze-cleaved corneas using a Hitachi S-570 scanning electron microscope in the high resolution mode (HRSEM). In order to study phototoxic effects in vitro, rabbit corneas (experimental) were cultured as organ culture in the presence of 5 micrograms/ml chlorpromazine (CPZ) and irradiated. For comparison, control 1 corneas were not irradiated but incubated in the dark without CPZ in the medium; control 2 corneas were also kept in the dark but in the presence of CPZ; control 3 corneas were irradiated with no CPZ in the medium. Cellular damage was not seen in the three types of control corneas, but in the experimental corneas the endothelial cells showed extensive disruption of the cell membrane and some deterioration of the intracellular components. Our study confirmed that HRSEM is a satisfactory new technique for visualizing damage of the intracellular organelles of corneal endothelium

  7. High resolution scanning electron microscopy of rabbit corneal endothelium to show effects of UV-visible irradiation in the presence of chlorpromazine

    Energy Technology Data Exchange (ETDEWEB)

    Lea, P.J.; Hollenberg, M.J.; Menon, I.A.; Temkin, R.J.; Persad, S.D.; Basu, P.K. (Univ. of Toronto, Ontario (Canada))

    1989-01-01

    The ultrastructure of rabbit cornea endothelial cells was examined by scanning electron microscopy (SEM) in freeze-cleaved corneas using a Hitachi S-570 scanning electron microscope in the high resolution mode (HRSEM). In order to study phototoxic effects in vitro, rabbit corneas (experimental) were cultured as organ culture in the presence of 5 micrograms/ml chlorpromazine (CPZ) and irradiated. For comparison, control 1 corneas were not irradiated but incubated in the dark without CPZ in the medium; control 2 corneas were also kept in the dark but in the presence of CPZ; control 3 corneas were irradiated with no CPZ in the medium. Cellular damage was not seen in the three types of control corneas, but in the experimental corneas the endothelial cells showed extensive disruption of the cell membrane and some deterioration of the intracellular components. Our study confirmed that HRSEM is a satisfactory new technique for visualizing damage of the intracellular organelles of corneal endothelium.

  8. High-resolution energetic particle measurements at 6.6 R/sub E/ 1. Electron micropulsations

    International Nuclear Information System (INIS)

    Higbie, P.R.; Belian, R.D.; Baker, D.N.

    1978-01-01

    The three papers dealing with data from satellites 1976--059A which we present in this issue represent the first publication of data from the new series of charged particle analyzer (CPA) instruments designed to measure energetic particle fluxes at geosynchronous altitudes. This first report presents new results on electron micropulsation phenomena and includes a concise description of the instrument. We often observe highly periodic modulations which persist for times as long as 2 hours in the spin-averaged counting rate data. These flux oscillations occur most frequently in the 30- to 300-keV electron data but are occasionally seen in higher-energy electron or low-energy proton data. The pitch angle distributions of the observed modulated fluxes may be either 'cigar-shaped' or 'pancake-shaped.' Oscillations at different energies are in phase, although the gross counting rate may be changing in an energy-time dispersive manner. The occurrence distribution of these modulations in local time suggests that they are related to Pc 5 geomagnetic micropulsations observed at ground stations

  9. Dysprosium disilicide nanostructures on silicon(001) studied by scanning tunneling microscopy and transmission electron microscopy

    International Nuclear Information System (INIS)

    Ye Gangfeng; Nogami, Jun; Crimp, Martin A.

    2006-01-01

    The microstructure of self-assembled dysprosium silicide nanostructures on silicon(001) has been studied by scanning tunneling microscopy and transmission electron microscopy. The studies focused on nanostructures that involve multiple atomic layers of the silicide. Cross-sectional high resolution transmission electron microscopy images and fast Fourier transform analysis showed that both hexagonal and orthorhombic/tetragonal silicide phases were present. Both the magnitude and the anisotropy of lattice mismatch between the silicide and the substrate play roles in the morphology and epitaxial growth of the nanostructures formed

  10. Study of the structure of the particles of channel black of phase-contrasting electron microscopy of high resolution

    Energy Technology Data Exchange (ETDEWEB)

    Varlakov, V.P.; Fialkov, A.S.; Smirnov, B.N.

    1981-01-01

    The structure of channel black, DG-100, in the initial and graphitized states has been studied by phase-contrasting electron microscopy with a direct resolution of the carbon layers. An individual carbon layer is the main structural element of carbon black. The structure of channel black in the graphitized state looks like a hollow closed polyhedron made up of bundles of continuous carbon layers which can bend and become deformed to a great extent, testifying to the polymeric nature of the structure of channel black. The authors give an interpretation of the roentgen values of the 'dimensions of crystallites' in channel black.

  11. Direct observation and analysis of york-shell materials using low-voltage high-resolution scanning electron microscopy: Nanometal-particles encapsulated in metal-oxide, carbon, and polymer

    Directory of Open Access Journals (Sweden)

    Shunsuke Asahina

    2014-11-01

    Full Text Available Nanometal particles show characteristic features in chemical and physical properties depending on their sizes and shapes. For keeping and further enhancing their features, the particles should be protected from coalescence or degradation. One approach is to encapsulate the nanometal particles inside pores with chemically inert or functional materials, such as carbon, polymer, and metal oxides, which contain mesopores to allow permeation of only chemicals not the nanometal particles. Recently developed low-voltage high-resolution scanning electron microscopy was applied to the study of structural, chemical, and electron state of both nanometal particles and encapsulating materials in york-shell materials of Au@C, Ru/Pt@C, Au@TiO2, and Pt@Polymer. Progresses in the following categories were shown for the york-shell materials: (i resolution of topographic image contrast by secondary electrons, of atomic-number contrast by back-scattered electrons, and of elemental mapping by X-ray energy dispersive spectroscopy; (ii sample preparation for observing internal structures; and (iii X-ray spectroscopy such as soft X-ray emission spectroscopy. Transmission electron microscopy was also used for characterization of Au@C.

  12. Direct observation and analysis of yolk-shell materials using low-voltage high-resolution scanning electron microscopy: Nanometal-particles encapsulated in metal-oxide, carbon, and polymer

    Energy Technology Data Exchange (ETDEWEB)

    Asahina, Shunsuke; Suga, Mitsuo; Takahashi, Hideyuki [JEOL Ltd., SM Business Unit, Tokyo (Japan); Young Jeong, Hu [Graduate School of EEWS, WCU/BK21+, KAIST, Daejeon 305-701 (Korea, Republic of); Galeano, Carolina; Schüth, Ferdi [Department of Heterogeneous Catalysis, Max-Planck-Institut für Kohlenforschung, Mülheim (Germany); Terasaki, Osamu, E-mail: terasaki@mmk.su.se, E-mail: terasaki@kaist.ac.kr [Graduate School of EEWS, WCU/BK21+, KAIST, Daejeon 305-701 (Korea, Republic of); Department of Materials and Environmental Chemistry, Berzelii Centre EXSELENT on Porous Materials, Stockholm University, SE-10691 Stockholm (Sweden)

    2014-11-01

    Nanometal particles show characteristic features in chemical and physical properties depending on their sizes and shapes. For keeping and further enhancing their features, the particles should be protected from coalescence or degradation. One approach is to encapsulate the nanometal particles inside pores with chemically inert or functional materials, such as carbon, polymer, and metal oxides, which contain mesopores to allow permeation of only chemicals not the nanometal particles. Recently developed low-voltage high-resolution scanning electron microscopy was applied to the study of structural, chemical, and electron state of both nanometal particles and encapsulating materials in yolk-shell materials of Au@C, Ru/Pt@C, Au@TiO{sub 2}, and Pt@Polymer. Progresses in the following categories were shown for the yolk-shell materials: (i) resolution of topographic image contrast by secondary electrons, of atomic-number contrast by back-scattered electrons, and of elemental mapping by X-ray energy dispersive spectroscopy; (ii) sample preparation for observing internal structures; and (iii) X-ray spectroscopy such as soft X-ray emission spectroscopy. Transmission electron microscopy was also used for characterization of Au@C.

  13. High-resolution mapping of 1D and 2D dose distributions using X-band electron paramagnetic resonance imaging

    International Nuclear Information System (INIS)

    Kolbun, N.; Lund, E.; Adolfsson, E.; Gustafsson, H.

    2014-01-01

    Electron paramagnetic resonance imaging (EPRI) was performed to visualise 2D dose distributions of homogeneously irradiated potassium dithionate tablets and to demonstrate determination of 1D dose profiles along the height of the tablets. Mathematical correction was applied for each relative dose profile in order to take into account the inhomogeneous response of the resonator using X-band EPRI. The dose profiles are presented with the spatial resolution of 0.6 mm from the acquired 2D images; this value is limited by pixel size, and 1D dose profiles from 1D imaging with spatial resolution of 0.3 mm limited by the intrinsic line-width of potassium dithionate. In this paper, dose profiles from 2D reconstructed electron paramagnetic resonance (EPR) images using the Xepr software package by Bruker are focussed. The conclusion is that using potassium dithionate, the resolution 0.3 mm is sufficient for mapping steep dose gradients if the dosemeters are covering only ±2 mm around the centre of the resonator. (authors)

  14. Quantitative transmission electron microscopy at atomic resolution

    International Nuclear Information System (INIS)

    Allen, L J; D'Alfonso, A J; Forbes, B D; Findlay, S D; LeBeau, J M; Stemmer, S

    2012-01-01

    In scanning transmission electron microscopy (STEM) it is possible to operate the microscope in bright-field mode under conditions which, by the quantum mechanical principle of reciprocity, are equivalent to those in conventional transmission electron microscopy (CTEM). The results of such an experiment will be presented which are in excellent quantitative agreement with theory for specimens up to 25 nm thick. This is at variance with the large contrast mismatch (typically between two and five) noted in equivalent CTEM experiments. The implications of this will be discussed.

  15. Optimization of the detector and associated electronics used for high-resolution liquid-scintillation alpha spectroscopy

    International Nuclear Information System (INIS)

    Thorngate, J.H.; Christian, D.J.

    1977-01-01

    The performance of various reflector geometries, light coupling liquids, photomultiplier tubes, preamplifiers and linear amplifiers were compared and the configuration found that optimized the combination of pulse-height resolution and pulse-shape discrimination. The best combination used a hemispherical reflector, filled with distilled water, coupled to an 8575 photomultiplier tube, the output of which was conditioned by a special integrating preamplifier and a double-delay-line linear amplifier. Careful choice of the scintillator, sample preparation procedures, and electronic apparatus can produce liquid-scintillation alpha spectroscopy with a pulse-height resolution of 300 keV, or less, and, by using pulse-shape discrimination, background levels as low as 0.01 counts/min. (author)

  16. High resolution electron back-scatter diffraction analysis of thermally and mechanically induced strains near carbide inclusions in a superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Karamched, Phani S., E-mail: phani.karamched@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Wilkinson, Angus J. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom)

    2011-01-15

    Cross-correlation-based analysis of electron back-scatter diffraction (EBSD) patterns has been used to obtain high angular resolution maps of lattice rotations and elastic strains near carbides in a directionally solidified superalloy MAR-M-002. Lattice curvatures were determined from the EBSD measurements and used to estimate the distribution of geometrically necessary dislocations (GNDs) induced by the deformation. Significant strains were induced by thermal treatment due to the lower thermal expansion coefficient of the carbide inclusions compared to that of the matrix. In addition to elastic strains the mismatch was sufficient to have induced localized plastic deformation in the matrix leading to a GND density of 3 x 10{sup 13} m{sup -2} in regions around the carbide. Three-point bending was then used to impose strain levels within the range {+-}12% across the height of the bend bar. EBSD lattice curvature measurements were then made at both carbide-containing and carbide-free regions at different heights across the bar. The average GND density increases with the magnitude of the imposed strain (both in tension and compression), and is markedly higher near the carbides particles. The higher GND densities near the carbides (order of 10{sup 14} m{sup -2}) are generated by the large strain gradients produced around the plastically rigid inclusion during mechanical deformation with some minor contribution from the pre-existing residual deformation caused by the thermal mismatch between carbide and nickel matrix.

  17. High resolution solar observations

    International Nuclear Information System (INIS)

    Title, A.

    1985-01-01

    Currently there is a world-wide effort to develop optical technology required for large diffraction limited telescopes that must operate with high optical fluxes. These developments can be used to significantly improve high resolution solar telescopes both on the ground and in space. When looking at the problem of high resolution observations it is essential to keep in mind that a diffraction limited telescope is an interferometer. Even a 30 cm aperture telescope, which is small for high resolution observations, is a big interferometer. Meter class and above diffraction limited telescopes can be expected to be very unforgiving of inattention to details. Unfortunately, even when an earth based telescope has perfect optics there are still problems with the quality of its optical path. The optical path includes not only the interior of the telescope, but also the immediate interface between the telescope and the atmosphere, and finally the atmosphere itself

  18. High-resolution electron spectroscopy of the 1s23lnl' Be-like series in oxygen and neon. Test of theoretical data: II. Experimental results

    International Nuclear Information System (INIS)

    Bordenave-Montesquieu, A; Moretto-Capelle, P; Bordenave-Montesquieu, D

    2003-01-01

    A complete and accurate experimental test of theoretical spectroscopic data sets (state positions, lifetimes) available for the n=3-5 terms of the 1s 2 3lnl' Rydberg series of oxygen and neon ions is presented in a series of two papers. This result was achieved by fitting our high-resolution electron spectra with post-collisional lineshapes calculated with the help of these spectroscopic data. In this second paper we apply the fitting procedure described in the preceding companion paper (I) to the analysis of high-resolution electron spectra measured in O 6+ (1s 2 ) + He, H 2 and Ne 8+ (1s 2 ) + He collisional systems at 10 qkeV collision energy (q is the ion charge). Singlet states alone are found to be excited in oxygen; they also explain most of the neon lines; in the latter case a possible contribution of triplet states is discussed. Many 1s 2 3lnl' 1 L transitions are identified for the first time. A quantitative comparison between measured and calculated positions clearly points to the best theoretical data currently available. Finally, a first identification of some 4l4l' 1 L transitions observed in the neon spectrum is also proposed. From this huge spectroscopic work, we extract the first experimental partial branching ratios for autoionization into the 1s 2 2l ionization continua for a large number of 1s 2 3lnl' 1 L states, which are compared with the total ones calculated by other authors; we deduce that populations of |M L vertical bar = 0 and 1 magnetic sublevels are nearly identical. The double-capture process is also briefly characterized by comparing relative populations of many n=3-5 states; it is found that the same states are populated in O 6+ +H 2 and Ne 8+ +He collisional systems with the same relative populations

  19. Imaging of soft and hard materials using a Boersch phase plate in a transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Alloyeau, D., E-mail: alloyeau.damien@gmail.com [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, One Cyclotron Road, MS/72, Berkeley, CA 94720 (United States); Hsieh, W.K. [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, One Cyclotron Road, MS/72, Berkeley, CA 94720 (United States); Anderson, E.H.; Hilken, L. [Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley CA 94720 (United States); Benner, G. [Carl Zeiss NTS GmbH, Oberkochen 73447 (Germany); Meng, X. [Electrical Engineering and Computer Sciences, UC Berkeley, Berkeley, CA 94720-1770 (United States); Chen, F.R. [Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan (China); Kisielowski, C. [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, One Cyclotron Road, MS/72, Berkeley, CA 94720 (United States)

    2010-04-15

    Using two levels of electron beam lithography, vapor phase deposition techniques, and FIB etching, we have fabricated an electrostatic Boersch phase plate for contrast enhancement of weak phase objects in a transmission electron microscope. The phase plate has suitable dimensions for the imaging of small biological samples without compromising the high-resolution capabilities of the microscope. A micro-structured electrode allows for phase tuning of the unscattered electron beam, which enables the recording of contrast enhanced in-focus images and in-line holograms. We have demonstrated experimentally that our phase plate improves the contrast of carbon nanotubes while maintaining high-resolution imaging performance, which is demonstrated for the case of an AlGaAs heterostructure. The development opens a new way to study interfaces between soft and hard materials.

  20. Transmission Electron Microscope Measures Lattice Parameters

    Science.gov (United States)

    Pike, William T.

    1996-01-01

    Convergent-beam microdiffraction (CBM) in thermionic-emission transmission electron microscope (TEM) is technique for measuring lattice parameters of nanometer-sized specimens of crystalline materials. Lattice parameters determined by use of CBM accurate to within few parts in thousand. Technique developed especially for use in quantifying lattice parameters, and thus strains, in epitaxial mismatched-crystal-lattice multilayer structures in multiple-quantum-well and other advanced semiconductor electronic devices. Ability to determine strains in indivdual layers contributes to understanding of novel electronic behaviors of devices.

  1. Isotope analysis in the transmission electron microscope.

    Science.gov (United States)

    Susi, Toma; Hofer, Christoph; Argentero, Giacomo; Leuthner, Gregor T; Pennycook, Timothy J; Mangler, Clemens; Meyer, Jannik C; Kotakoski, Jani

    2016-10-10

    The Ångström-sized probe of the scanning transmission electron microscope can visualize and collect spectra from single atoms. This can unambiguously resolve the chemical structure of materials, but not their isotopic composition. Here we differentiate between two isotopes of the same element by quantifying how likely the energetic imaging electrons are to eject atoms. First, we measure the displacement probability in graphene grown from either 12 C or 13 C and describe the process using a quantum mechanical model of lattice vibrations coupled with density functional theory simulations. We then test our spatial resolution in a mixed sample by ejecting individual atoms from nanoscale areas spanning an interface region that is far from atomically sharp, mapping the isotope concentration with a precision better than 20%. Although we use a scanning instrument, our method may be applicable to any atomic resolution transmission electron microscope and to other low-dimensional materials.

  2. Iterative reconstruction of magnetic induction using Lorentz transmission electron tomography

    International Nuclear Information System (INIS)

    Phatak, C.; Gürsoy, D.

    2015-01-01

    Intense ongoing research on complex nanomagnetic structures requires a fundamental understanding of the 3D magnetization and the stray fields around the nano-objects. 3D visualization of such fields offers the best way to achieve this. Lorentz transmission electron microscopy provides a suitable combination of high resolution and ability to quantitatively visualize the magnetization vectors using phase retrieval methods. In this paper, we present a formalism to represent the magnetic phase shift of electrons as a Radon transform of the magnetic induction of the sample. Using this formalism, we then present the application of common tomographic methods particularly the iterative methods, to reconstruct the 3D components of the vector field. We present an analysis of the effect of missing wedge and the limited angular sampling as well as reconstruction of complex 3D magnetization in a nanowire using simulations. - Highlights: • We present a formalism to represent electron-optical magnetic phase shift as a Radon transform of the 3D magnetic induction of the nano-object. • We have analyzed four different tomographic reconstruction methods for vectorial data reconstruction. • Reconstruction methods were tested for varying experimental limitations such as limited tilt range and limited angular sampling. • The analysis showed that Gridrec and SIRT methods performed better with lower errors than other reconstruction methods

  3. Test Particle Simulations of Electron Injection by the Bursty Bulk Flows (BBFs) using High Resolution Lyon-Feddor-Mobarry (LFM) Code

    Science.gov (United States)

    Eshetu, W. W.; Lyon, J.; Wiltberger, M. J.; Hudson, M. K.

    2017-12-01

    Test particle simulations of electron injection by the bursty bulk flows (BBFs) have been done using a test particle tracer code [1], and the output fields of the Lyon-Feddor-Mobarry global magnetohydro- dynamics (MHD) code[2]. The MHD code was run with high resolu- tion (oct resolution), and with specified solar wind conditions so as to reproduce the observed qualitative picture of the BBFs [3]. Test par- ticles were injected so that they interact with earthward propagating BBFs. The result of the simulation shows that electrons are pushed ahead of the BBFs and accelerated into the inner magnetosphere. Once electrons are in the inner magnetosphere they are further energized by drift resonance with the azimuthal electric field. In addition pitch angle scattering of electrons resulting in the violation conservation of the first adiabatic invariant has been observed. The violation of the first adiabatic invariant occurs as electrons cross a weak magnetic field region with a strong gradient of the field perturbed by the BBFs. References 1. Kress, B. T., Hudson,M. K., Looper, M. D. , Albert, J., Lyon, J. G., and Goodrich, C. C. (2007), Global MHD test particle simulations of ¿ 10 MeV radiation belt electrons during storm sudden commencement, J. Geophys. Res., 112, A09215, doi:10.1029/2006JA012218. Lyon,J. G., Fedder, J. A., and Mobarry, C.M., The Lyon- Fedder-Mobarry (LFM) Global MHD Magnetospheric Simulation Code (2004), J. Atm. And Solar-Terrestrial Phys., 66, Issue 15-16, 1333- 1350,doi:10.1016/j.jastp. Wiltberger, Merkin, M., Lyon, J. G., and Ohtani, S. (2015), High-resolution global magnetohydrodynamic simulation of bursty bulk flows, J. Geophys. Res. Space Physics, 120, 45554566, doi:10.1002/2015JA021080.

  4. High-resolution energetic particle measurements at 6.6R/sub E/ 3. Low-energy electron anisotropies and short-term substorm predictions

    International Nuclear Information System (INIS)

    Baker, D.N.; Higbie, P.R.; Hones, E.W. Jr.; Belian, R.D.

    1978-01-01

    Multiple detectors giving nearly complete 4π coverage of particle pitch angle distributions have provided high resolution measurements (in energy and time) of 30- to 300-keV electrons. Data from a spacecraft (1976-059A) in geostationary orbit show a remarkably consistent sequence of variations of the electron anisotropy before and during magnetospheric substorms. For periods typically 1--2 hours prior to the onset of substorms, electron distributions, peaked along the direction of the local magnetic field, are observed in the premidnight sector. These cigarlike anisotropies are accompanied by a local taillike magnetic field which may develop further during the event. At substorm onset an abrupt transition usually occurs from the cigar-shaped distributions to pancake-shaped distributions. This anisotropy sequence may be due to the buildup and subsequent release of stresses in the magnetotail; the cigar phase may also be due to associated processes at the dayside magnetopause causing a loss of 90 0 pitch angle particles. The present observations, based on approx.100 events, appear to provide a predictive tool for assessing the probability of occurrence of a substorm

  5. High Resolution Higher Energy X-ray Microscope for Mesoscopic Materials

    International Nuclear Information System (INIS)

    Snigireva, I; Snigirev, A

    2013-01-01

    We developed a novel X-ray microscopy technique to study mesoscopically structured materials, employing compound refractive lenses. The easily seen advantage of lens-based methodology is the possibility to retrieve high resolution diffraction pattern and real-space images in the same experimental setup. Methodologically the proposed approach is similar to the studies of crystals by high resolution transmission electron microscopy. The proposed microscope was applied for studying of mesoscopic materials such as natural and synthetic opals, inverted photonic crystals

  6. Elemental mapping in scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Allen, L J; D'Alfonso, A J; Lugg, N R; Findlay, S D; LeBeau, J M; Stemmer, S

    2010-01-01

    We discuss atomic resolution chemical mapping in scanning transmission electron microscopy (STEM) based on core-loss electron energy loss spectroscopy (EELS) and also on energy dispersive X-ray (EDX) imaging. Chemical mapping using EELS can yield counterintuitive results which, however, can be understood using first principles calculations. Experimental chemical maps based on EDX bear out the thesis that such maps are always likely to be directly interpretable. This can be explained in terms of the local nature of the effective optical potential for ionization under those imaging conditions. This is followed by an excursion into the complementary technique of elemental mapping using energy-filtered transmission electron microscopy (EFTEM) in a conventional transmission electron microscope. We will then consider the widely used technique of Z-contrast or high-angle annular dark field (HAADF) imaging, which is based on phonon excitation, where it has recently been shown that intensity variations can be placed on an absolute scale by normalizing the measured intensities to the incident beam. Results, showing excellent agreement between theory and experiment to within a few percent, are shown for Z-contrast imaging from a sample of PbWO 4 .

  7. Transmission Electron Microscopy of Minerals and Rocks

    Science.gov (United States)

    McLaren, Alex C.

    1991-04-01

    Of the many techniques that have been applied to the study of crystal defects, none has contributed more to our understanding of their nature and influence on the physical and chemical properties of crystalline materials than transmission electron microscopy (TEM). TEM is now used extensively by an increasing number of earth scientists for direct observation of defect microstructures in minerals and rocks. Transmission Electron Microscopy of Rocks and Minerals is an introduction to the principles of the technique and is the only book to date on the subject written specifically for geologists and mineralogists. The first part of the book deals with the essential physics of the transmission electron microscope and presents the basic theoretical background required for the interpretation of images and electron diffraction patterns. The final chapters are concerned with specific applications of TEM in mineralogy and deal with such topics as planar defects, intergrowths, radiation-induced defects, dislocations and deformation-induced microstructures. The examples cover a wide range of rock-forming minerals from crustal rocks to those in the lower mantle, and also take into account the role of defects in important mineralogical and geological processes.

  8. Probing the electronic structure and Au–C chemical bonding in AuC2− and AuC2 using high-resolution photoelectron spectroscopy

    International Nuclear Information System (INIS)

    León, Iker; Yang, Zheng; Wang, Lai-Sheng

    2014-01-01

    We report photoelectron spectroscopy (PES) and high-resolution PE imaging of AuC 2 − at a wide range of photon energies. The ground state of AuC 2 − is found to be linear (C ∞v , 1 Σ + ) with a …8π 4 4δ 4 17σ 2 9π 4 18σ 2 valence configuration. Detachments from all the five valence orbitals of the ground state of AuC 2 − are observed at 193 nm. High-resolution PE images are obtained in the energy range from 830 to 330 nm, revealing complicated vibronic structures from electron detachment of the 18σ, 9π, and 17σ orbitals. Detachment from the 18σ orbital results in the 2 Σ + ground state of neutral AuC 2 , which, however, is bent due to strong vibronic coupling with the nearby 2 Π state from detachment of a 9π electron. The 2 Σ + – 2 Π vibronic and spin-orbit coupling results in complicated vibronic structures for the 2 Σ + and 2 Π 3/2 states with extensive bending excitations. The electron affinity of AuC 2 is measured accurately to be 3.2192(7) eV with a ground state bending frequency of 195(6) cm −1 . The first excited state ( 2 A′) of AuC 2 , corresponding to the 2 Π 3/2 state at the linear geometry, is only 0.0021 eV above the ground state ( 2 A′) and has a bending frequency of 207(6) cm −1 . The 2 Π 1/2 state, 0.2291 eV above the ground state, is linear with little geometry change relative to the anion ground state. The detachment of the 17σ orbital also results in complicated vibronic structures, suggesting again a bent state due to possible vibronic coupling with the lower 2 Π state. The spectrum at 193 nm shows the presence of a minor species with less than 2% intensity relative to the ground state of AuC 2 − . High-resolution data of the minor species reveal several vibrational progressions in the Au–C stretching mode, which are assigned to be from the metastable 3 Π 2,1,0 spin-orbit excited states of AuC 2 − to the 2 Π 3/2,1/2 spin-orbit states of neutral AuC 2 . The spin-orbit splittings of the 3 Π and 2

  9. High resolution data acquisition

    Science.gov (United States)

    Thornton, Glenn W.; Fuller, Kenneth R.

    1993-01-01

    A high resolution event interval timing system measures short time intervals such as occur in high energy physics or laser ranging. Timing is provided from a clock (38) pulse train (37) and analog circuitry (44) for generating a triangular wave (46) synchronously with the pulse train (37). The triangular wave (46) has an amplitude and slope functionally related to the time elapsed during each clock pulse in the train. A converter (18, 32) forms a first digital value of the amplitude and slope of the triangle wave at the start of the event interval and a second digital value of the amplitude and slope of the triangle wave at the end of the event interval. A counter (26) counts the clock pulse train (37) during the interval to form a gross event interval time. A computer (52) then combines the gross event interval time and the first and second digital values to output a high resolution value for the event interval.

  10. ANL high resolution injector

    International Nuclear Information System (INIS)

    Minehara, E.; Kutschera, W.; Hartog, P.D.; Billquist, P.

    1985-01-01

    The ANL (Argonne National Laboratory) high-resolution injector has been installed to obtain higher mass resolution and higher preacceleration, and to utilize effectively the full mass range of ATLAS (Argonne Tandem Linac Accelerator System). Preliminary results of the first beam test are reported briefly. The design and performance, in particular a high-mass-resolution magnet with aberration compensation, are discussed. 7 refs., 5 figs., 2 tabs

  11. Ultra high resolution tomography

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, W.S.

    1994-11-15

    Recent work and results on ultra high resolution three dimensional imaging with soft x-rays will be presented. This work is aimed at determining microscopic three dimensional structure of biological and material specimens. Three dimensional reconstructed images of a microscopic test object will be presented; the reconstruction has a resolution on the order of 1000 A in all three dimensions. Preliminary work with biological samples will also be shown, and the experimental and numerical methods used will be discussed.

  12. High resolution (transformers.

    Science.gov (United States)

    Garcia-Souto, Jose A; Lamela-Rivera, Horacio

    2006-10-16

    A novel fiber-optic interferometric sensor is presented for vibrations measurements and analysis. In this approach, it is shown applied to the vibrations of electrical structures within power transformers. A main feature of the sensor is that an unambiguous optical phase measurement is performed using the direct detection of the interferometer output, without external modulation, for a more compact and stable implementation. High resolution of the interferometric measurement is obtained with this technique (transformers are also highlighted.

  13. Correlating Fluorescence and High-Resolution Scanning Electron Microscopy (HRSEM) for the study of GABAA receptor clustering induced by inhibitory synaptic plasticity

    KAUST Repository

    Orlando, Marta; Ravasenga, Tiziana; Petrini, Enrica Maria; Falqui, Andrea; Marotta, Roberto; Barberis, Andrea

    2017-01-01

    Both excitatory and inhibitory synaptic contacts display activity dependent dynamic changes in their efficacy that are globally termed synaptic plasticity. Although the molecular mechanisms underlying glutamatergic synaptic plasticity have been extensively investigated and described, those responsible for inhibitory synaptic plasticity are only beginning to be unveiled. In this framework, the ultrastructural changes of the inhibitory synapses during plasticity have been poorly investigated. Here we combined confocal fluorescence microscopy (CFM) with high resolution scanning electron microscopy (HRSEM) to characterize the fine structural rearrangements of post-synaptic GABAA Receptors (GABAARs) at the nanometric scale during the induction of inhibitory long-term potentiation (iLTP). Additional electron tomography (ET) experiments on immunolabelled hippocampal neurons allowed the visualization of synaptic contacts and confirmed the reorganization of post-synaptic GABAAR clusters in response to chemical iLTP inducing protocol. Altogether, these approaches revealed that, following the induction of inhibitory synaptic potentiation, GABAAR clusters increase in size and number at the post-synaptic membrane with no other major structural changes of the pre- and post-synaptic elements.

  14. Correlating Fluorescence and High-Resolution Scanning Electron Microscopy (HRSEM) for the study of GABAA receptor clustering induced by inhibitory synaptic plasticity

    KAUST Repository

    Orlando, Marta

    2017-10-17

    Both excitatory and inhibitory synaptic contacts display activity dependent dynamic changes in their efficacy that are globally termed synaptic plasticity. Although the molecular mechanisms underlying glutamatergic synaptic plasticity have been extensively investigated and described, those responsible for inhibitory synaptic plasticity are only beginning to be unveiled. In this framework, the ultrastructural changes of the inhibitory synapses during plasticity have been poorly investigated. Here we combined confocal fluorescence microscopy (CFM) with high resolution scanning electron microscopy (HRSEM) to characterize the fine structural rearrangements of post-synaptic GABAA Receptors (GABAARs) at the nanometric scale during the induction of inhibitory long-term potentiation (iLTP). Additional electron tomography (ET) experiments on immunolabelled hippocampal neurons allowed the visualization of synaptic contacts and confirmed the reorganization of post-synaptic GABAAR clusters in response to chemical iLTP inducing protocol. Altogether, these approaches revealed that, following the induction of inhibitory synaptic potentiation, GABAAR clusters increase in size and number at the post-synaptic membrane with no other major structural changes of the pre- and post-synaptic elements.

  15. Quantitative measurement of mean inner potential and specimen thickness from high-resolution off-axis electron holograms of ultra-thin layered WSe2.

    Science.gov (United States)

    Winkler, Florian; Tavabi, Amir H; Barthel, Juri; Duchamp, Martial; Yucelen, Emrah; Borghardt, Sven; Kardynal, Beata E; Dunin-Borkowski, Rafal E

    2017-07-01

    The phase and amplitude of the electron wavefunction that has passed through ultra-thin flakes of WSe 2 is measured from high-resolution off-axis electron holograms. Both the experimental measurements and corresponding computer simulations are used to show that, as a result of dynamical diffraction, the spatially averaged phase does not increase linearly with specimen thickness close to an [001] zone axis orientation even when the specimen has a thickness of only a few layers. It is then not possible to infer the local specimen thickness of the WSe 2 from either the phase or the amplitude alone. Instead, we show that the combined analysis of phase and amplitude from experimental measurements and simulations allows an accurate determination of the local specimen thickness. The relationship between phase and projected potential is shown to be approximately linear for extremely thin specimens that are tilted by several degrees in certain directions from the [001] zone axis. A knowledge of the specimen thickness then allows the electrostatic potential to be determined from the measured phase. By using this combined approach, we determine a value for the mean inner potential of WSe 2 of 18.9±0.8V, which is 12% lower than the value calculated from neutral atom scattering factors. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  16. Correlating Fluorescence and High-Resolution Scanning Electron Microscopy (HRSEM) for the study of GABAA receptor clustering induced by inhibitory synaptic plasticity.

    Science.gov (United States)

    Orlando, Marta; Ravasenga, Tiziana; Petrini, Enrica Maria; Falqui, Andrea; Marotta, Roberto; Barberis, Andrea

    2017-10-23

    Both excitatory and inhibitory synaptic contacts display activity dependent dynamic changes in their efficacy that are globally termed synaptic plasticity. Although the molecular mechanisms underlying glutamatergic synaptic plasticity have been extensively investigated and described, those responsible for inhibitory synaptic plasticity are only beginning to be unveiled. In this framework, the ultrastructural changes of the inhibitory synapses during plasticity have been poorly investigated. Here we combined confocal fluorescence microscopy (CFM) with high resolution scanning electron microscopy (HRSEM) to characterize the fine structural rearrangements of post-synaptic GABA A Receptors (GABA A Rs) at the nanometric scale during the induction of inhibitory long-term potentiation (iLTP). Additional electron tomography (ET) experiments on immunolabelled hippocampal neurons allowed the visualization of synaptic contacts and confirmed the reorganization of post-synaptic GABA A R clusters in response to chemical iLTP inducing protocol. Altogether, these approaches revealed that, following the induction of inhibitory synaptic potentiation, GABA A R clusters increase in size and number at the post-synaptic membrane with no other major structural changes of the pre- and post-synaptic elements.

  17. Transmission electron microscopy in micro-nanoelectronics

    CERN Document Server

    Claverie, Alain

    2013-01-01

    Today, the availability of bright and highly coherent electron sources and sensitive detectors has radically changed the type and quality of the information which can be obtained by transmission electron microscopy (TEM). TEMs are now present in large numbers not only in academia, but also in industrial research centers and fabs.This book presents in a simple and practical way the new quantitative techniques based on TEM which have recently been invented or developed to address most of the main challenging issues scientists and process engineers have to face to develop or optimize sem

  18. Transmission Electron Microscopy and Diffractometry of Materials

    CERN Document Server

    Fultz, Brent

    2013-01-01

    This book explains concepts of transmission electron microscopy (TEM) and x-ray diffractometry (XRD) that are important for the characterization of materials. The fourth edition adds important new techniques of TEM such as electron tomography, nanobeam diffraction, and geometric phase analysis. A new chapter on neutron scattering completes the trio of x-ray, electron and neutron diffraction. All chapters were updated and revised for clarity. The book explains the fundamentals of how waves and wavefunctions interact with atoms in solids, and the similarities and differences of using x-rays, electrons, or neutrons for diffraction measurements. Diffraction effects of crystalline order, defects, and disorder in materials are explained in detail. Both practical and theoretical issues are covered. The book can be used in an introductory-level or advanced-level course, since sections are identified by difficulty. Each chapter includes a set of problems to illustrate principles, and the extensive Appendix includes la...

  19. Transmission/Scanning Transmission Electron Microscopy | Materials Science

    Science.gov (United States)

    crystallographic structure of a material. Amplitude-contrast images yield information about the chemistry and microstructure of a material and its defects. Phase-contrast imaging or high-resolution (HR) TEM imaging gives information about the microstructure of a material and its defects at an atomic resolution. With scanning

  20. Thin dielectric film thickness determination by advanced transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Diebold, A.C.; Foran, B.; Kisielowski, C.; Muller, D.; Pennycook, S.; Principe, E.; Stemmer, S.

    2003-09-01

    High Resolution Transmission Electron Microscopy (HR-TEM) has been used as the ultimate method of thickness measurement for thin films. The appearance of phase contrast interference patterns in HR-TEM images has long been confused as the appearance of a crystal lattice by non-specialists. Relatively easy to interpret crystal lattice images are now directly observed with the introduction of annular dark field detectors for scanning TEM (STEM). With the recent development of reliable lattice image processing software that creates crystal structure images from phase contrast data, HR-TEM can also provide crystal lattice images. The resolution of both methods was steadily improved reaching now into the sub Angstrom region. Improvements in electron lens and image analysis software are increasing the spatial resolution of both methods. Optimum resolution for STEM requires that the probe beam be highly localized. In STEM, beam localization is enhanced by selection of the correct aperture. When STEM measurement is done using a highly localized probe beam, HR-TEM and STEM measurement of the thickness of silicon oxynitride films agree within experimental error. In this paper, the optimum conditions for HR-TEM and STEM measurement are discussed along with a method for repeatable film thickness determination. The impact of sample thickness is also discussed. The key result in this paper is the proposal of a reproducible method for film thickness determination.

  1. Amyloid Structure and Assembly: Insights from Scanning Transmission Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Goldsbury, C.; Wall, J.; Baxa, U.; Simon, M. N.; Steven, A. C.; Engel, A.; Aebi, U.; Muller, S. A.

    2011-01-01

    Amyloid fibrils are filamentous protein aggregates implicated in several common diseases such as Alzheimer's disease and type II diabetes. Similar structures are also the molecular principle of the infectious spongiform encephalopathies such as Creutzfeldt-Jakob disease in humans, scrapie in sheep, and of the so-called yeast prions, inherited non-chromosomal elements found in yeast and fungi. Scanning transmission electron microscopy (STEM) is often used to delineate the assembly mechanism and structural properties of amyloid aggregates. In this review we consider specifically contributions and limitations of STEM for the investigation of amyloid assembly pathways, fibril polymorphisms and structural models of amyloid fibrils. This type of microscopy provides the only method to directly measure the mass-per-length (MPL) of individual filaments. Made on both in vitro assembled and ex vivo samples, STEM mass measurements have illuminated the hierarchical relationships between amyloid fibrils and revealed that polymorphic fibrils and various globular oligomers can assemble simultaneously from a single polypeptide. The MPLs also impose strong constraints on possible packing schemes, assisting in molecular model building when combined with high-resolution methods like solid-state nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR).

  2. High-resolution electron microscopy studies of the precipitation of copper under neutron irradiation in an Fe-1.3WT% Cu alloy

    International Nuclear Information System (INIS)

    Nicol, A. C.

    1998-01-01

    We have studied by electron microscopy the copper-rich precipitates in an Fe-1.3wt%Cu model alloy irradiated with neutrons to doses of 8.61 x 10 -3 dpa and 6.3 x 10 -2 dpa at a temperature of ∼270 C. In the lower dose material a majority (ca. 60%)of the precipitates visible in high-resolution electron microscopy were timed 9R precipitates of size ∼2-4 nm, while ca. 40% were untwinned. In the higher dose material, a majority (ca. 75%) of visible precipitates were untwinned although many still seemed to have a 9R structure. The average angle α between the herring-bone fringes in the twin variants was measured as 125 degree, not the 129 degree characteristic of precipitates in thermally-aged and electron-irradiated material immediately after the bcc->9R martensitic transformation. We argue that these results imply that the bcc->9R transformation of small (<4 nm) precipitates under neutron irradiation takes place at the irradiation temperature of 270 C rather than after subsequent cooling. Preliminary measurements showed that precipitate sizes did not depend strongly on dose, with a mean diameter of 3.4 ± 0.7 nm for the lower dose material, and 3.0 ± 0.5 nm for the higher dose material. This result agrees with the previous assumption that the lack of coarsening in precipitates formed under neutron irradiation is a consequence of the partial dissolution of larger precipitates by high-energy cascades

  3. Characterization of a direct detection device imaging camera for transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Milazzo, Anna-Clare, E-mail: amilazzo@ncmir.ucsd.edu [University of California at San Diego, 9500 Gilman Dr., La Jolla, CA 92093 (United States); Moldovan, Grigore [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Lanman, Jason [Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037 (United States); Jin, Liang; Bouwer, James C. [University of California at San Diego, 9500 Gilman Dr., La Jolla, CA 92093 (United States); Klienfelder, Stuart [University of California at Irvine, Irvine, CA 92697 (United States); Peltier, Steven T.; Ellisman, Mark H. [University of California at San Diego, 9500 Gilman Dr., La Jolla, CA 92093 (United States); Kirkland, Angus I. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Xuong, Nguyen-Huu [University of California at San Diego, 9500 Gilman Dr., La Jolla, CA 92093 (United States)

    2010-06-15

    The complete characterization of a novel direct detection device (DDD) camera for transmission electron microscopy is reported, for the first time at primary electron energies of 120 and 200 keV. Unlike a standard charge coupled device (CCD) camera, this device does not require a scintillator. The DDD transfers signal up to 65 lines/mm providing the basis for a high-performance platform for a new generation of wide field-of-view high-resolution cameras. An image of a thin section of virus particles is presented to illustrate the substantially improved performance of this sensor over current indirectly coupled CCD cameras.

  4. Characterization of a direct detection device imaging camera for transmission electron microscopy

    International Nuclear Information System (INIS)

    Milazzo, Anna-Clare; Moldovan, Grigore; Lanman, Jason; Jin, Liang; Bouwer, James C.; Klienfelder, Stuart; Peltier, Steven T.; Ellisman, Mark H.; Kirkland, Angus I.; Xuong, Nguyen-Huu

    2010-01-01

    The complete characterization of a novel direct detection device (DDD) camera for transmission electron microscopy is reported, for the first time at primary electron energies of 120 and 200 keV. Unlike a standard charge coupled device (CCD) camera, this device does not require a scintillator. The DDD transfers signal up to 65 lines/mm providing the basis for a high-performance platform for a new generation of wide field-of-view high-resolution cameras. An image of a thin section of virus particles is presented to illustrate the substantially improved performance of this sensor over current indirectly coupled CCD cameras.

  5. In situ investigation of ion-induced dewetting of a thin iron-oxide film on silicon by high resolution scanning electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Amirthapandian, S. [Institut fuer Halbleiteroptik und Funktionelle Grenzflaechen, Universitaet Stuttgart, 70569 Stuttgart (Germany); Material Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Schuchart, F.; Garmatter, D.; Bolse, W. [Institut fuer Halbleiteroptik und Funktionelle Grenzflaechen, Universitaet Stuttgart, 70569 Stuttgart (Germany)

    2012-11-15

    Using our new in situ high resolution scanning electron microscope, which is integrated into the UNILAC ion beamline at the Helmholtzzentrum fuer Schwerionenforschung (GSI) in Darmstadt, Germany, we investigated the swift heavy ion induced dewetting of a thin iron oxide layer on Si. Besides heterogeneous hole nucleation at defects and spontaneous (homogeneous) hole nucleation, we could clearly identify a dewetting mechanism, which is similar to the spinodal dewetting observed for liquid films. Instead of being due to capillary waves, it is based on a stress induced surface instability. The latter results in the formation of a wavy surface with constant dominant wave-length and increasing amplitude during ion irradiation. Dewetting sets in as soon as the wave-troughs reach the film-substrate interface. Inspection of the hole radii and rim shapes indicates that removal of the material from the hole area occurs mainly by plastic deformation at the inner boundary and ion induced viscous flow in the peripheral zone due to surface tension.

  6. Structural characterization of epitaxial YBa2Cu3O7 thin films on step-edge substrates by means of high-resolution electron microscopy

    International Nuclear Information System (INIS)

    Jia, C.L.; Kabius, B.; Urban, K.

    1993-01-01

    The microstructure of YBa 2 Cu 3 O 7 films epitaxially grown on step-edge (0 0 1) SrTiO 3 and LaAlO 3 substrates has been characterized by means of high-resolution electron microscopy. The results indicate a relationship between the microstructure of the film across a step and the angle the step makes with the substrate plane. On a steep, high-angle step, the film grows with its c-axis perpendicular to that of the film on substrate surface so that two grain boundaries are formed. In the upper grain boundary, on the average, a (0 1 3) habit plane alternates with a (1 0 3) habit plane. This alternating structure is caused by twinning in the orthorhombic structure. The lower boundaries consist of a chain of (0 1 3)(0 1 3) and (0 1 0)(0 0 1) type segments exhibiting a tendency to tilt the whole habit plane toward the a-b plane of the flank film. Dislocations, stacking faults and misfit strains were also observed in or close to the boundaries. (orig.)

  7. Fermi surface of a disordered Cu-Al -alloy single crystal studied by high-resolution Compton scattering and electron diffraction

    Science.gov (United States)

    Kwiatkowska, J.; Maniawski, F.; Matsumoto, I.; Kawata, H.; Shiotani, N.; Lityńska, L.; Kaprzyk, S.; Bansil, A.

    2004-08-01

    We have measured high resolution Compton scattering profiles for momentum transfer along a series of 28 independent directions from Cu0.842Al0.158 disordered alloy single crystals with normals to the surfaces oriented along the [100], [110], and [111] directions. The experimental spectra are interpreted via parallel first-principles KKR-CPA (Korringa-Kohn-Rostoker coherent-potential approximation) computations of these directional profiles. The Fermi surface determined by inverting the Compton data is found to be in good agreement with the KKR-CPA predictions. An electron diffraction study of the present Cu0.842Al0.158 sample is additionally undertaken to gain insight into short-range ordering effects. The scattering pattern displays not only the familiar diffuse scattering peaks, but also shows the presence of weak streaks interconnecting the four diffuse scattering spots around the (110) reciprocal lattice points. This study provides a comprehensive picture of the evolution of the shape of the Fermi surface of Cu with the addition of Al . Our results are consistent with the notion that Fermi surface nesting is an important factor in driving short-range ordering effects in disordered alloys.

  8. Hydration Effects on Skin Microstructure as Probed by High-Resolution Cryo-Scanning Electron Microscopy and Mechanistic Implications to Enhanced Transcutaneous Delivery of Biomacromolecules

    Science.gov (United States)

    Tan, Grace; Xu, Peng; Lawson, Louise B.; He, Jibao; Freytag, Lucia C.; Clements, John D.; John, Vijay T.

    2010-01-01

    Although hydration is long known to improve the permeability of skin, penetration of macromolecules such as proteins is limited and the understanding of enhanced transport is based on empirical observations. This study uses high-resolution cryo-scanning electron microscopy to visualize microstructural changes in the stratum corneum (SC) and enable a mechanistic interpretation of biomacromolecule penetration through highly hydrated porcine skin. Swollen corneocytes, separation of lipid bilayers in the SC intercellular space to form cisternae, and networks of spherical particulates are observed in porcine skin tissue hydrated for a period of 4–10 h. This is explained through compaction of skin lipids when hydrated, a reversal in the conformational transition from unilamellar liposomes in lamellar granules to lamellae between keratinocytes when the SC skin barrier is initially established. Confocal microscopy studies show distinct enhancement in penetration of fluorescein isothiocyanate-bovine serum albumin (FITC-BSA) through skin hydrated for 4–10 h, and limited penetration of FITC-BSA once skin is restored to its natively hydrated structure when exposed to the environment for 2–3 h. These results demonstrate the effectiveness of a 4–10 h hydration period to enhance transcutaneous penetration of large biomacromolecules without permanently damaging the skin. PMID:19582754

  9. High-resolution noise substitution to measure overfitting and validate resolution in 3D structure determination by single particle electron cryomicroscopy.

    Science.gov (United States)

    Chen, Shaoxia; McMullan, Greg; Faruqi, Abdul R; Murshudov, Garib N; Short, Judith M; Scheres, Sjors H W; Henderson, Richard

    2013-12-01

    Three-dimensional (3D) structure determination by single particle electron cryomicroscopy (cryoEM) involves the calculation of an initial 3D model, followed by extensive iterative improvement of the orientation determination of the individual particle images and the resulting 3D map. Because there is much more noise than signal at high resolution in the images, this creates the possibility of noise reinforcement in the 3D map, which can give a false impression of the resolution attained. The balance between signal and noise in the final map at its limiting resolution depends on the image processing procedure and is not easily predicted. There is a growing awareness in the cryoEM community of how to avoid such over-fitting and over-estimation of resolution. Equally, there has been a reluctance to use the two principal methods of avoidance because they give lower resolution estimates, which some people believe are too pessimistic. Here we describe a simple test that is compatible with any image processing protocol. The test allows measurement of the amount of signal and the amount of noise from overfitting that is present in the final 3D map. We have applied the method to two different sets of cryoEM images of the enzyme beta-galactosidase using several image processing packages. Our procedure involves substituting the Fourier components of the initial particle image stack beyond a chosen resolution by either the Fourier components from an adjacent area of background, or by simple randomisation of the phases of the particle structure factors. This substituted noise thus has the same spectral power distribution as the original data. Comparison of the Fourier Shell Correlation (FSC) plots from the 3D map obtained using the experimental data with that from the same data with high-resolution noise (HR-noise) substituted allows an unambiguous measurement of the amount of overfitting and an accompanying resolution assessment. A simple formula can be used to calculate an

  10. High-resolution noise substitution to measure overfitting and validate resolution in 3D structure determination by single particle electron cryomicroscopy

    International Nuclear Information System (INIS)

    Chen, Shaoxia; McMullan, Greg; Faruqi, Abdul R.; Murshudov, Garib N.; Short, Judith M.; Scheres, Sjors H.W.; Henderson, Richard

    2013-01-01

    Three-dimensional (3D) structure determination by single particle electron cryomicroscopy (cryoEM) involves the calculation of an initial 3D model, followed by extensive iterative improvement of the orientation determination of the individual particle images and the resulting 3D map. Because there is much more noise than signal at high resolution in the images, this creates the possibility of noise reinforcement in the 3D map, which can give a false impression of the resolution attained. The balance between signal and noise in the final map at its limiting resolution depends on the image processing procedure and is not easily predicted. There is a growing awareness in the cryoEM community of how to avoid such over-fitting and over-estimation of resolution. Equally, there has been a reluctance to use the two principal methods of avoidance because they give lower resolution estimates, which some people believe are too pessimistic. Here we describe a simple test that is compatible with any image processing protocol. The test allows measurement of the amount of signal and the amount of noise from overfitting that is present in the final 3D map. We have applied the method to two different sets of cryoEM images of the enzyme beta-galactosidase using several image processing packages. Our procedure involves substituting the Fourier components of the initial particle image stack beyond a chosen resolution by either the Fourier components from an adjacent area of background, or by simple randomisation of the phases of the particle structure factors. This substituted noise thus has the same spectral power distribution as the original data. Comparison of the Fourier Shell Correlation (FSC) plots from the 3D map obtained using the experimental data with that from the same data with high-resolution noise (HR-noise) substituted allows an unambiguous measurement of the amount of overfitting and an accompanying resolution assessment. A simple formula can be used to calculate an

  11. High-resolution noise substitution to measure overfitting and validate resolution in 3D structure determination by single particle electron cryomicroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shaoxia; McMullan, Greg; Faruqi, Abdul R.; Murshudov, Garib N.; Short, Judith M.; Scheres, Sjors H.W.; Henderson, Richard, E-mail: rh15@mrc-lmb.cam.ac.uk

    2013-12-15

    Three-dimensional (3D) structure determination by single particle electron cryomicroscopy (cryoEM) involves the calculation of an initial 3D model, followed by extensive iterative improvement of the orientation determination of the individual particle images and the resulting 3D map. Because there is much more noise than signal at high resolution in the images, this creates the possibility of noise reinforcement in the 3D map, which can give a false impression of the resolution attained. The balance between signal and noise in the final map at its limiting resolution depends on the image processing procedure and is not easily predicted. There is a growing awareness in the cryoEM community of how to avoid such over-fitting and over-estimation of resolution. Equally, there has been a reluctance to use the two principal methods of avoidance because they give lower resolution estimates, which some people believe are too pessimistic. Here we describe a simple test that is compatible with any image processing protocol. The test allows measurement of the amount of signal and the amount of noise from overfitting that is present in the final 3D map. We have applied the method to two different sets of cryoEM images of the enzyme beta-galactosidase using several image processing packages. Our procedure involves substituting the Fourier components of the initial particle image stack beyond a chosen resolution by either the Fourier components from an adjacent area of background, or by simple randomisation of the phases of the particle structure factors. This substituted noise thus has the same spectral power distribution as the original data. Comparison of the Fourier Shell Correlation (FSC) plots from the 3D map obtained using the experimental data with that from the same data with high-resolution noise (HR-noise) substituted allows an unambiguous measurement of the amount of overfitting and an accompanying resolution assessment. A simple formula can be used to calculate an

  12. High-Resolution Faraday Rotation and Electron-Phonon Coupling in Surface States of the Bulk-Insulating Topological Insulator Cu_{0.02}Bi_{2}Se_{3}.

    Science.gov (United States)

    Wu, Liang; Tse, Wang-Kong; Brahlek, M; Morris, C M; Aguilar, R Valdés; Koirala, N; Oh, S; Armitage, N P

    2015-11-20

    We have utilized time-domain magnetoterahertz spectroscopy to investigate the low-frequency optical response of the topological insulator Cu_{0.02}Bi_{2}Se_{3} and Bi_{2}Se_{3} films. With both field and frequency dependence, such experiments give sufficient information to measure the mobility and carrier density of multiple conduction channels simultaneously. We observe sharp cyclotron resonances (CRs) in both materials. The small amount of Cu incorporated into the Cu_{0.02}Bi_{2}Se_{3} induces a true bulk insulator with only a single type of conduction with a total sheet carrier density of ~4.9×10^{12}/cm^{2} and mobility as high as 4000 cm^{2}/V·s. This is consistent with conduction from two virtually identical topological surface states (TSSs) on the top and bottom of the film with a chemical potential ~145 meV above the Dirac point and in the bulk gap. The CR broadens at high fields, an effect that we attribute to an electron-phonon interaction. This assignment is supported by an extended Drude model analysis of the zero-field Drude conductance. In contrast, in normal Bi_{2}Se_{3} films, two conduction channels were observed, and we developed a self-consistent analysis method to distinguish the dominant TSSs and coexisting trivial bulk or two-dimensional electron gas states. Our high-resolution Faraday rotation spectroscopy on Cu_{0.02}Bi_{2}Se_{3} paves the way for the observation of quantized Faraday rotation under experimentally achievable conditions to push the chemical potential in the lowest Landau level.

  13. High-Resolution Spectroscopy of Jet-Cooled 1,1 '-Diphenylethylene: Electronically Excited and Ionic States of a Prototypical Cross-Conjugated System

    NARCIS (Netherlands)

    Smolarek, S.; Vdovin, A.; Rijs, A.; van Walree, C. A.; Zgierski, M. Z.; Buma, W. J.

    2011-01-01

    The photophysics of a prototypical cross-conjugated pi-system, 1,1'-diphenylethylene, have been studied using high-resolution resonance enhanced multiphoton ionization excitation spectroscopy and zero kinetic energy photoelectron spectroscopy, in combination with advanced ab initio

  14. Environment-Dependent Surface Dynamics of Supported Gold Nanoparticles Studied by High-Resolution Transmission Electron Microscopy

    DEFF Research Database (Denmark)

    Liu, Pei

    there is a variety of configurations which can be considered as local minima in potential energies in configurational space. The relations between particles and substrate have been studied. Particle motion on the substrates are in three manners, such as rigid sliding, movement via mass transport and rigid rotation...... is mainly on the (111) facet. In the last part of the thesis, the reversibility and local strain field variation of the twinning-detwinning processes suggest twins play an important role in the catalytic reaction....

  15. Transmission electron microscopy of mercury metal

    KAUST Repository

    Anjum, Dalaver H.

    2016-03-28

    Summary: Transmission electron microcopy (TEM) analysis of liquid metals, especially mercury (Hg), is difficult to carry out because their specimen preparation poses a daunting task due to the unique surface properties of these metals. This paper reports a cryoTEM study on Hg using a novel specimen preparation technique. Hg metal is mixed with water using sonication and quenched in liquid ethane cryogen. This technique permits research into the morphological, phase and structural properties of Hg at nanoscale dimensions. © 2016 Royal Microscopical Society.

  16. Electron dose dependence of signal-to-noise ratio, atom contrast and resolution in transmission electron microscope images

    International Nuclear Information System (INIS)

    Lee, Z.; Rose, H.; Lehtinen, O.; Biskupek, J.; Kaiser, U.

    2014-01-01

    In order to achieve the highest resolution in aberration-corrected (AC) high-resolution transmission electron microscopy (HRTEM) images, high electron doses are required which only a few samples can withstand. In this paper we perform dose-dependent AC-HRTEM image calculations, and study the dependence of the signal-to-noise ratio, atom contrast and resolution on electron dose and sampling. We introduce dose-dependent contrast, which can be used to evaluate the visibility of objects under different dose conditions. Based on our calculations, we determine optimum samplings for high and low electron dose imaging conditions. - Highlights: • The definition of dose-dependent atom contrast is introduced. • The dependence of the signal-to-noise ratio, atom contrast and specimen resolution on electron dose and sampling is explored. • The optimum sampling can be determined according to different dose conditions

  17. High resolution ultrasonic densitometer

    International Nuclear Information System (INIS)

    Dress, W.B.

    1983-01-01

    The velocity of torsional stress pulses in an ultrasonic waveguide of non-circular cross section is affected by the temperature and density of the surrounding medium. Measurement of the transit times of acoustic echoes from the ends of a sensor section are interpreted as level, density, and temperature of the fluid environment surrounding that section. This paper examines methods of making these measurements to obtain high resolution, temperature-corrected absolute and relative density and level determinations of the fluid. Possible applications include on-line process monitoring, a hand-held density probe for battery charge state indication, and precise inventory control for such diverse fluids as uranium salt solutions in accountability storage and gasoline in service station storage tanks

  18. An improved experimental scheme for simultaneous measurement of high-resolution zero electron kinetic energy (ZEKE) photoelectron and threshold photoion (MATI) spectra

    Science.gov (United States)

    Michels, François; Mazzoni, Federico; Becucci, Maurizio; Müller-Dethlefs, Klaus

    2017-10-01

    An improved detection scheme is presented for threshold ionization spectroscopy with simultaneous recording of the Zero Electron Kinetic Energy (ZEKE) and Mass Analysed Threshold Ionisation (MATI) signals. The objective is to obtain accurate dissociation energies for larger molecular clusters by simultaneously detecting the fragment and parent ion MATI signals with identical transmission. The scheme preserves an optimal ZEKE spectral resolution together with excellent separation of the spontaneous ion and MATI signals in the time-of-flight mass spectrum. The resulting improvement in sensitivity will allow for the determination of dissociation energies in clusters with substantial mass difference between parent and daughter ions.

  19. Cathodoluminescence in the scanning transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Kociak, M., E-mail: mathieu.kociak@u-psud.fr [Laboratoire de Physique des Solides, Université Paris-SudParis-Sud, CNRS-UMR 8502, Orsay 91405 (France); Zagonel, L.F. [“Gleb Wataghin” Institute of Physics University of Campinas - UNICAMP, 13083-859 Campinas, São Paulo (Brazil)

    2017-05-15

    Cathodoluminescence (CL) is a powerful tool for the investigation of optical properties of materials. In recent years, its combination with scanning transmission electron microscopy (STEM) has demonstrated great success in unveiling new physics in the field of plasmonics and quantum emitters. Most of these results were not imaginable even twenty years ago, due to conceptual and technical limitations. The purpose of this review is to present the recent advances that broke these limitations, and the new possibilities offered by the modern STEM-CL technique. We first introduce the different STEM-CL operating modes and the technical specificities in STEM-CL instrumentation. Two main classes of optical excitations, namely the coherent one (typically plasmons) and the incoherent one (typically light emission from quantum emitters) are investigated with STEM-CL. For these two main classes, we describe both the physics of light production under electron beam irradiation and the physical basis for interpreting STEM-CL experiments. We then compare STEM-CL with its better known sister techniques: scanning electron microscope CL, photoluminescence, and electron energy-loss spectroscopy. We finish by comprehensively reviewing recent STEM-CL applications. - Highlights: • Reviews the field of STEM-CL. • Introduces the technical requirements and challenges for STEM-CL. • Introduces the different types of excitations probed by STEM-CL. • Gives comprehensive overview of the last fifteenth years in the field.

  20. Quantitative biological measurement in Transmission Electron Tomography

    International Nuclear Information System (INIS)

    Mantell, Judith M; Verkade, Paul; Arkill, Kenton P

    2012-01-01

    It has been known for some time that biological sections shrink in the transmission electron microscope from exposure to the electron beam. This phenomenon is especially important in Electron Tomography (ET). The effect on shrinkage of parameters such as embedding medium or sample type is less well understood. In addition anisotropic area shrinkage has largely been ignored. The intention of this study is to explore the shrinkage on a number of samples ranging in thickness from 200 nm to 500 nm. A protocol was developed to determine the shrinkage in area and thickness using the gold fiducials used in electron tomography. In brief: Using low dose philosophy on the section, a focus area was used prior to a separate virgin study area for a series of known exposures on a tilted sample. The shrinkage was determined by measurements on the gold beads from both sides of the section as determined by a confirmatory tomogram. It was found that the shrinkage in area (approximately to 90-95% of the original) and the thickness (approximately 65% of the original at most) agreed with pervious authors, but that a lmost all the shrinkage was in the first minute and that although the direction of the in-plane shrinkage (in x and y) was sometimes uneven the end result was consistent. It was observed, in general, that thinner samples showed more percentage shrinkage than thicker ones. In conclusion, if direct quantitative measurements are required then the protocol described should be used for all areas studied.

  1. Quantitative biological measurement in Transmission Electron Tomography

    Science.gov (United States)

    Mantell, Judith M.; Verkade, Paul; Arkill, Kenton P.

    2012-07-01

    It has been known for some time that biological sections shrink in the transmission electron microscope from exposure to the electron beam. This phenomenon is especially important in Electron Tomography (ET). The effect on shrinkage of parameters such as embedding medium or sample type is less well understood. In addition anisotropic area shrinkage has largely been ignored. The intention of this study is to explore the shrinkage on a number of samples ranging in thickness from 200 nm to 500 nm. A protocol was developed to determine the shrinkage in area and thickness using the gold fiducials used in electron tomography. In brief: Using low dose philosophy on the section, a focus area was used prior to a separate virgin study area for a series of known exposures on a tilted sample. The shrinkage was determined by measurements on the gold beads from both sides of the section as determined by a confirmatory tomogram. It was found that the shrinkage in area (approximately to 90-95% of the original) and the thickness (approximately 65% of the original at most) agreed with pervious authors, but that a lmost all the shrinkage was in the first minute and that although the direction of the in-plane shrinkage (in x and y) was sometimes uneven the end result was consistent. It was observed, in general, that thinner samples showed more percentage shrinkage than thicker ones. In conclusion, if direct quantitative measurements are required then the protocol described should be used for all areas studied.

  2. Electron energy loss spectroscopy microanalysis and imaging in the transmission electron microscope: example of biological applications

    International Nuclear Information System (INIS)

    Diociaiuti, Marco

    2005-01-01

    This paper reports original results obtained in our laboratory over the past few years in the application of both electron energy loss spectroscopy (EELS) and electron spectroscopy imaging (ESI) to biological samples, performed in two transmission electron microscopes (TEM) equipped with high-resolution electron filters and spectrometers: a Gatan model 607 single magnetic sector double focusing EEL serial spectrometer attached to a Philips 430 TEM and a Zeiss EM902 Energy Filtering TEM. The primary interest was on the possibility offered by the combined application of these spectroscopic techniques with those offered by the TEM. In particular, the electron beam focusing available in a TEM allowed us to perform EELS and ESI on very small sample volumes, where high-resolution imaging and electron diffraction techniques can provide important structural information. I show that ESI was able to improve TEM performance, due to the reduced chromatic aberration and the possibility of avoiding the sample staining procedure. Finally, the analysis of the oscillating extended energy loss fine structure (EXELFS) beyond the ionization edges characterizing the EELS spectra allowed me, in a manner very similar to the extended X-ray absorption fine structure (EXAFS) analysis of the X-ray absorption spectra, to obtain short-range structural information for such light elements of biological interest as O or Fe. The Philips EM430 (250-300 keV) TEM was used to perform EELS microanalysis on Ca, P, O, Fe, Al and Si. The assessment of the detection limits of this method was obtained working with well-characterized samples containing Ca and P, and mimicking the actual cellular matrix. I applied EELS microanalysis to Ca detection in bone tissue during the mineralization process and to P detection in the cellular membrane of erythrocytes treated with an anti-tumoral drug, demonstrating that the cellular membrane is a drug target. I applied EELS microanalysis and selected area electron

  3. Characterization of nanomaterials with transmission electron microscopy

    KAUST Repository

    Anjum, Dalaver H.

    2016-08-01

    The field of nanotechnology is about research and development on materials whose at least one dimension is in the range of 1 to 100 nanometers. In recent years, the research activity for developing nano-materials has grown exponentially owing to the fact that they offer better solutions to the challenges faced by various fields such as energy, food, and environment. In this paper, the importance of transmission electron microscopy (TEM) based techniques is demonstrated for investigating the properties of nano-materials. Specifically the nano-materials that are investigated in this report include gold nano-particles (Au-NPs), silver atom-clusters (Ag-ACs), tantalum single-atoms (Ta-SAs), carbon materials functionalized with iron cobalt (Fe-Co) NPs and titania (TiO2) NPs, and platinum loaded Ceria (Pt-CeO2) Nano composite. TEM techniques that are employed to investigate nano-materials include aberration corrected bright-field TEM (BF-TEM), high-angle dark-field scanning TEM (HAADF-STEM), electron energy-loss spectroscopy (EELS), and BF-TEM electron tomography (ET). With the help presented of results in this report, it is proved herein that as many TEM techniques as available in a given instrument are essential for a comprehensive nano-scale analysis of nanomaterials.

  4. Transmission electron microscopy on live catalysts

    NARCIS (Netherlands)

    Bremmer, G.M.

    2017-01-01

    The dissertation describes TEM experiments on heterogeneous catalysts. Starting with characterization of (Ni/Co)MoS2 on Alumina and the effect of oxidation, and sequential resulfidation. After that, Co-based catalysts are used for high-resolution (S)TEM/EDX caracterization studies, and in situ

  5. Atomic imaging using secondary electrons in a scanning transmission electron microscope: experimental observations and possible mechanisms.

    Science.gov (United States)

    Inada, H; Su, D; Egerton, R F; Konno, M; Wu, L; Ciston, J; Wall, J; Zhu, Y

    2011-06-01

    We report detailed investigation of high-resolution imaging using secondary electrons (SE) with a sub-nanometer probe in an aberration-corrected transmission electron microscope, Hitachi HD2700C. This instrument also allows us to acquire the corresponding annular dark-field (ADF) images both simultaneously and separately. We demonstrate that atomic SE imaging is achievable for a wide range of elements, from uranium to carbon. Using the ADF images as a reference, we studied the SE image intensity and contrast as functions of applied bias, atomic number, crystal tilt, and thickness to shed light on the origin of the unexpected ultrahigh resolution in SE imaging. We have also demonstrated that the SE signal is sensitive to the terminating species at a crystal surface. A possible mechanism for atomic-scale SE imaging is proposed. The ability to image both the surface and bulk of a sample at atomic-scale is unprecedented, and can have important applications in the field of electron microscopy and materials characterization. Copyright © 2010 Elsevier B.V. All rights reserved.

  6. Thermal diffuse scattering in transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Forbes, B.D.; D' Alfonso, A.J. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Findlay, S.D. [School of Physics, Monash University, Victoria 3800 (Australia); Van Dyck, D. [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); LeBeau, J.M. [North Carolina State University, Raleigh, NC 27695-7907 (United States); Stemmer, S. [Materials Department, University of California, Santa Barbara, CA 93106-5050 (United States); Allen, L.J., E-mail: lja@unimelb.edu.au [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia)

    2011-12-15

    In conventional transmission electron microscopy, thermal scattering significantly affects the image contrast. It has been suggested that not accounting for this correctly is the main cause of the Stobbs factor, the ubiquitous, large contrast mismatch found between theory and experiment. In the case where a hard aperture is applied, we show that previous conclusions drawn from work using bright field scanning transmission electron microscopy and invoking the principle of reciprocity are reliable in the presence of thermal scattering. In the aperture-free case it has been suggested that even the most sophisticated mathematical models for thermal diffuse scattering lack in their numerical implementation, specifically that there may be issues in sampling, including that of the contrast transfer function of the objective lens. We show that these concerns can be satisfactorily overcome with modest computing resources; thermal scattering can be modelled accurately enough for the purpose of making quantitative comparison between simulation and experiment. Spatial incoherence of the source is also investigated. Neglect or inadequate handling of thermal scattering in simulation can have an appreciable effect on the predicted contrast and can be a significant contribution to the Stobbs factor problem. -- Highlights: Black-Right-Pointing-Pointer We determine the numerical requirements for accurate simulation of TDS in CTEM. Black-Right-Pointing-Pointer TDS can be simulated to high precision using the Born-Oppenheimer model. Black-Right-Pointing-Pointer Such calculations establish the contribution of TDS to the Stobbs factor problem. Black-Right-Pointing-Pointer Treating spatial incoherence using envelope functions increases image contrast. Black-Right-Pointing-Pointer Rigorous treatment of spatial incoherence significantly reduces image contrast.

  7. High-resolution spectroscopy of jet-cooled 1,1 '-diphenylethylene: electronically excited and ionic states of a prototypical cross-conjugated system

    NARCIS (Netherlands)

    Smolarek, S.; Vdovin, A.; Rijs, A.; van Walree, C.A.; Zgierski, M.Z.; Buma, W.J.

    2011-01-01

    The photophysics of a prototypical cross-conjugated π-system, 1,1′-diphenylethylene, have been studied using high-resolution resonance enhanced multiphoton ionization excitation spectroscopy and zero kinetic energy photoelectron spectroscopy, in combination with advanced ab initio calculations. We

  8. In situ transmission electron microscopy analyses of thermally annealed self catalyzed GaAs nanowires grown by molecular beam epitaxy

    DEFF Research Database (Denmark)

    Ambrosini, S.; Wagner, Jakob Birkedal; Booth, Tim

    2011-01-01

    Self catalyzed GaAs nanowires grown on Si-treated GaAs substrates were studied with a transmission electron microscope before and after annealing at 600◦C. At room temperature the nanowires have a zincblende structure and are locally characterized by a high density of rotational twins and stacking...... faults. Selected area diffraction patterns and high-resolution transmission electron microscopy images show that nanowires undergo structural modifications upon annealing, suggesting a decrease of defect density following the thermal treatment....

  9. High-resolution parallel electron energy-loss spectroscopy of MnL2,3-edges in inorganic manganese compounds

    International Nuclear Information System (INIS)

    Garvie, L.A.J.; Craven, A.J.

    1994-01-01

    Parallel electron energy-loss spectroscopy (PEELS) in a scanning transmission electron microscope (STEM) was used to record the Mn L 2,3 -edges from a range of natural and synthetic manganese containing materials, covering valences 0, II, III, IV and VII, with an energy resolution of ca. 0.5 eV. The Mn L 2,3 electron-loss near-edge structure (ELNES) of these edges provided a sensitive fingerprint of its valence. The Mn 2+ L 2,3 -edges show little sensitivity to the local site symmetry of the ligands surrounding the manganese. This is illustrated by comparing the Mn L 2,3 -edges from 4-, 6-and 8-fold coordinated Mn 2+ . In contrast, the Mn L 3 -edges from Mn 3+ and Mn 4+ containing minerals exhibited ELNES that are interpreted in terms of a crystals-field splitting of the 3d electrons, governed by the symmetry of the surrounding ligands. The Mn L 3 -edges for octahedrally coordinated Mn 2+ , Mn 3+ and Mn 4+ showed variations in their ELNES that were sensitive to the crystal-field strength. The crystal-field strength (10Q) was measured from these edges and compared very well with published optically determinted values. The magnitude of 10Dq measured from the Mn L 3 -edges and their O K-edge prepeaks of the manganese oxides were almost identical. This further confirms that the value of 10Dq measured at the Mn L 3 -edge is correct. Selected spectra are compared with theoretical 2p atomic multiplet spectra and the differences and similarities are explained in terms of the covalency and site symmetry of the manganese. The Mn L 3 -edges allow the valence of the manganese to be ascertained, even in multivalent state materials, and can also be used to dtermin 10Dq. (orig.)

  10. High-resolution structure of the Shigella type-III secretion needle by solid-state NMR and cryo-electron microscopy

    Science.gov (United States)

    Demers, Jean-Philippe; Habenstein, Birgit; Loquet, Antoine; Kumar Vasa, Suresh; Giller, Karin; Becker, Stefan; Baker, David; Lange, Adam; Sgourakis, Nikolaos G.

    2014-09-01

    We introduce a general hybrid approach for determining the structures of supramolecular assemblies. Cryo-electron microscopy (cryo-EM) data define the overall envelope of the assembly and rigid-body orientation of the subunits while solid-state nuclear magnetic resonance (ssNMR) chemical shifts and distance constraints define the local secondary structure, protein fold and inter-subunit interactions. Finally, Rosetta structure calculations provide a general framework to integrate the different sources of structural information. Combining a 7.7-Å cryo-EM density map and 996 ssNMR distance constraints, the structure of the type-III secretion system needle of Shigella flexneri is determined to a precision of 0.4 Å. The calculated structures are cross-validated using an independent data set of 691 ssNMR constraints and scanning transmission electron microscopy measurements. The hybrid model resolves the conformation of the non-conserved N terminus, which occupies a protrusion in the cryo-EM density, and reveals conserved pore residues forming a continuous pattern of electrostatic interactions, thereby suggesting a mechanism for effector protein translocation.

  11. Structural changes of Bi1.8Sr2(Ca1-xYx)Cu2.2Oz ceramics with yttrium content studied by electron diffraction and high-resolution electron microscopy

    Science.gov (United States)

    Onozuka, Takashi; Iwabuchi, Yoshihiro; Fukase, Tetsuo; Sato, Hiroshi; Mitchell, Terence E.

    1991-06-01

    The mode of the incommensurate modulation in the b direction of the Bi1.8Sr2(Ca1-xYx)Cu2.2Oz (0.05electron diffraction and high-resolution lattice imaging. The change of period of the long-period structure with x is found to be basically due to the mixing ratio of domains of two modulation periods with b=4.5b0 and 5b0 or 4.5b0 and 4b0, thus creating periods of b=4.75b0-4.0b0. The fundamental orthorhombic lattice has dimensions of a~=b~=b0 (0.54 nm) and c~=c0 (3.1 nm). The change of the mixing mode from one to the other mentioned above occurs just in the yttrium concentration range, 0.45high-resolution lattice images. These images are reproduced well by a multislice computer-simulation technique.

  12. Transmission electron microscopy and Raman characterization of copper (I) oxide microspheres composed of nanoparticles

    International Nuclear Information System (INIS)

    Wang Wenzhong; Tu Ya; Wang Lijuan; Liang Yujie; Shi Honglong

    2013-01-01

    Highlights: ► Raman spectroscopy of copper (I) oxide microspheres were investigated. ► Infrared active mode is greatly activated in Raman scattering spectrum. ► Infrared active mode shows up in Raman spectrum of copper (I) oxide microspheres. ► The defects existed in spheres could be responsible for the observed Raman property. - Abstract: The high-resolution transmission electron microscope and Raman spectroscopy were used to investigate the microstructures and Raman scattering property of copper (I) oxide microspheres composed of nanoparticles. High-resolution transmission electron microscope images indicate that the copper (I) oxide microspheres are composed of nanoparticles with random growth direction, indicating that there are many defects in microspheres. The Raman spectrum shows that infrared active mode, which must be odd parity and is Raman forbidden for bulk crystal due to its inversion symmetry, is activated and shows up in Raman scattering spectrum. On the basis of investigations of the microstructure features of copper (I) oxide microspheres, we attribute the appearance of IR active mode in Raman scattering spectrum to the breakdown of the symmetry of the lattice due to the presence of defects in the prepared copper (I) oxide microspheres as observed in HRTEM images.

  13. Experimental positions and lifetimes of Be-like 1s23lnl'(n=3 to 5) states of O4+ and Ne6+ ions investigated by high resolution electron spectroscopy: test of calculations

    International Nuclear Information System (INIS)

    Bordenave-Montesquieu, A.; Moretto-Capelle, P.; Bordenave-Montesquieu, D.

    1999-01-01

    Using high resolution electron spectroscopy, positions and lifetimes of many Be-like singlet states of the 1s 2 3lnl' Rydberg series (n = 3 to 5) of oxygen and neon have been measured for the first time. This was achieved by a fitting procedure which takes into account an accurate definition of the post-collisional electron lineshapes. These states are produced after a double electron capture by multicharged ions has occurred in O 6+ (1s 2 )+He, H 2 and Ne 8+ (1s 2 )+He collisions at about 4 keV/amu collision energy. (orig.)

  14. Transmission Electron Microscopy of a CMSX-4 Ni-Base Superalloy Produced by Selective Electron Beam Melting

    Directory of Open Access Journals (Sweden)

    Alireza B. Parsa

    2016-10-01

    Full Text Available In this work, the microstructures of superalloy specimens produced using selective electron beam melting additive manufacturing were characterized. The materials were produced using a CMSX-4 powder. Two selective electron beam melting processing strategies, which result in higher and lower effective cooling rates, are described. Orientation imaging microscopy, scanning transmission electron microscopy and conventional high resolution transmission electron microscopy are used to investigate the microstructures. Our results suggest that selective electron beam melting processing results in near equilibrium microstructures, as far as γ′ volume fractions, the formation of small amounts of TCP phases and the partitioning behavior of the alloy elements are concerned. As expected, higher cooling rates result in smaller dendrite spacings, which are two orders of magnitude smaller than observed during conventional single crystal casting. During processing, columnar grains grow in <100> directions, which are rotated with respect to each other. There are coarse γ/γ′ microstructures in high angle boundary regions. Dislocation networks form low angle boundaries. A striking feature of the as processed selective electron beam melting specimens is their high dislocation density. From a fundamental point of view, this opens new possibilities for the investigation of elementary dislocation processes which accompany solidification.

  15. Ab initio transmission electron microscopy image simulations of coherent Ag-MgO interfaces

    International Nuclear Information System (INIS)

    Mogck, S.; Kooi, B.J.; Hosson, J.Th.M. de; Finnis, M.W.

    2004-01-01

    Density-functional theory calculations, within the plane-wave-ultrasoft pseudopotential framework, were performed in the projection for MgO and for the coherent (111) Ag-MgO polar interface. First-principles calculations were incorporated in high-resolution transmission electron microscopy (HRTEM) simulations by converting the charge density into electron scattering factors to examine the influence of charge transfer, charge redistribution at the interface, and ionicity on the dynamical electron scattering and on calculated HRTEM images. It is concluded that the ionicity of oxides and the charge redistribution at interfaces play a significant role in HRTEM image simulations. In particular, the calculations show that at oxygen-terminated (111) Ag-MgO interfaces the first oxygen layer at the interface is much brighter than that in calculations with neutral atoms, in agreement with experimental observations

  16. Nucleation of diamond by pure carbon ion bombardment--a transmission electron microscopy study

    International Nuclear Information System (INIS)

    Yao, Y.; Liao, M.Y.; Wang, Z.G.; Lifshitz, Y.; Lee, S.

    2005-01-01

    A cross-sectional high-resolution transmission electron microscopy (HRTEM) study of a film deposited by a 1 keV mass-selected carbon ion beam onto silicon held at 800 deg. C is presented. Initially, a graphitic film with its basal planes perpendicular to the substrate is evolving. The precipitation of nanodiamond crystallites in upper layers is confirmed by HRTEM, selected area electron diffraction, and electron energy loss spectroscopy. The nucleation of diamond on graphitic edges as predicted by Lambrecht et al. [W. R. L. Lambrecht, C. H. Lee, B. Segall, J. C. Angus, Z. Li, and M. Sunkara, Nature, 364 607 (1993)] is experimentally confirmed. The results are discussed in terms of our recent subplantation-based diamond nucleation model

  17. Atomistic observations and analyses of lattice defects in transmission electron microscopes

    CERN Document Server

    Abe, H

    2003-01-01

    The transmission electron microscope (TEM) -accelerators was developed. TEM-Accelerator made possible to observe in situ experiments of ion irradiation and implantation. The main results are the experimental proof of new lattice defects by irradiation, the formation process and synthesized conditions of carbon onion by ion implantation, the microstructure and phase transformation conditions of graphite by ion irradiated phase transformation, the irradiation damage formation process by simultaneous irradiation of electron and ion and behavior of fullerene whisker under irradiation. The microstructural evolution of defect clusters in copper irradiated with 240-keV Cu sup + ions and a high resolution electron micrograph of carbon onions synthesized by ion implantation are explained as the examples of recent researches. (S.Y.)

  18. Observations of localised dielectric excitations, secondary events and ionisation damage by scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Howie, A.

    1988-01-01

    In the scanning transmission electron microscope (STEM) a high intensity /approximately/0.5nm diameter, probe of 100 keV electrons is formed. This can be positioned to collect energy loss spectra from surfaces, interfaces, small spheres or other particles at controlled values of impact parameter or can be scanned across the object (usually a thin film) to produce high resolution images formed from a variety of signals - small angle or large angle (Z contrast) elastic scattering, inelastic scattering (both valence and core losses), secondary electron emission and x-ray or optical photon emission. The high spatial resolution achievable in a variety of simple structures raises many unsolved theoretical problems concerning the generation, propagation and decay of excitations in inhomogeneous media. These range from quite well posed problems in the mathematical physics of dielectric excitation to problems of plasmon propagation and rather more exotic and less well understood problems of radiation damage. 15 refs., 4 figs

  19. Experimental transmission electron microscopy studies and phenomenological model of bismuth-based superconducting compounds

    International Nuclear Information System (INIS)

    Elboussiri, Khalid

    1991-01-01

    The main part of this thesis is devoted to an experimental study by transmission electron microscopy of the different phases of the superconducting bismuth cuprates Bi_2Sr_2Ca_n_-_1Cu_nO_2_n_+_4. In high resolution electron microscopy, the two types of incommensurate modulation realized in these compounds have been observed. A model of structure has been proposed from which the simulated images obtained are consistent with observations. The medium resolution images correlated with the electron diffraction data have revealed existence of a multi-soliton regime with latent lock in phases of commensurate periods between 4b and 10b. At last, a description of different phases of these compounds as a result of superstructures from a disordered perovskite type structure is proposed (author) [fr

  20. Ultra-high-resolution inelastic X-ray scattering at high-repetition-rate self-seeded X-ray free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Chubar, Oleg [Brookhaven National Laboratory, Upton, NY 11973 (United States); Geloni, Gianluca [European X-ray Free-Electron Laser, Albert-Einstein-Ring 19, 22761 Hamburg (Germany); Kocharyan, Vitali [Deutsches Elektronen-Synchrotron, 22761 Hamburg (Germany); Madsen, Anders [European X-ray Free-Electron Laser, Albert-Einstein-Ring 19, 22761 Hamburg (Germany); Saldin, Evgeni; Serkez, Svitozar [Deutsches Elektronen-Synchrotron, 22761 Hamburg (Germany); Shvyd’ko, Yuri, E-mail: shvydko@aps.anl.gov [Argonne National Laboratory, Argonne, IL 60439 (United States); Sutter, John [Diamond Light Source Ltd, Didcot OX11 0DE (United Kingdom)

    2016-02-12

    This article explores novel opportunities for ultra-high-resolution inelastic X-ray scattering (IXS) at high-repetition-rate self-seeded XFELs. These next-generation light sources are promising a more than three orders of magnitude increase in average spectral flux compared with what is possible with storage-ring-based radiation sources. In combination with the advanced IXS spectrometer described here, this may become a real game-changer for ultra-high-resolution X-ray spectroscopies, and hence for the studies of dynamics in condensed matter systems. Inelastic X-ray scattering (IXS) is an important tool for studies of equilibrium dynamics in condensed matter. A new spectrometer recently proposed for ultra-high-resolution IXS (UHRIX) has achieved 0.6 meV and 0.25 nm{sup −1} spectral and momentum-transfer resolutions, respectively. However, further improvements down to 0.1 meV and 0.02 nm{sup −1} are required to close the gap in energy–momentum space between high- and low-frequency probes. It is shown that this goal can be achieved by further optimizing the X-ray optics and by increasing the spectral flux of the incident X-ray pulses. UHRIX performs best at energies from 5 to 10 keV, where a combination of self-seeding and undulator tapering at the SASE-2 beamline of the European XFEL promises up to a 100-fold increase in average spectral flux compared with nominal SASE pulses at saturation, or three orders of magnitude more than what is possible with storage-ring-based radiation sources. Wave-optics calculations show that about 7 × 10{sup 12} photons s{sup −1} in a 90 µeV bandwidth can be achieved on the sample. This will provide unique new possibilities for dynamics studies by IXS.

  1. High-resolution multi-slice PET

    International Nuclear Information System (INIS)

    Yasillo, N.J.; Chintu Chen; Ordonez, C.E.; Kapp, O.H.; Sosnowski, J.; Beck, R.N.

    1992-01-01

    This report evaluates the progress to test the feasibility and to initiate the design of a high resolution multi-slice PET system. The following specific areas were evaluated: detector development and testing; electronics configuration and design; mechanical design; and system simulation. The design and construction of a multiple-slice, high-resolution positron tomograph will provide substantial improvements in the accuracy and reproducibility of measurements of the distribution of activity concentrations in the brain. The range of functional brain research and our understanding of local brain function will be greatly extended when the development of this instrumentation is completed

  2. Transmission of electrons through Al2O3 nanocapillaries

    DEFF Research Database (Denmark)

    Milosavljević, A.R.; Jureta, J.J.; Víkor, Gy.

    2012-01-01

    We investigate transmission of low-energy electrons (250 eV) through insulating AlO nanocapillaries (270 nm diameter and 15 μm length). Kinetic energy distribution of electrons transmitted through the nanocapillaries in the straightforward direction, time dependence of the transmission rate both...

  3. Progress in high-resolution x-ray holographic microscopy

    International Nuclear Information System (INIS)

    Jacobsen, C.; Kirz, J.; Howells, M.; McQuaid, K.; Rothman, S.; Feder, R.; Sayre, D.

    1987-07-01

    Among the various types of x-ray microscopes that have been demonstrated, the holographic microscope has had the largest gap between promise and performance. The difficulties of fabricating x-ray optical elements have led some to view holography as the most attractive method for obtaining the ultimate in high resolution x-ray micrographs; however, we know of no investigations prior to 1987 that clearly demonstrated submicron resolution in reconstructed images. Previous efforts suffered from problems such as limited resolution and dynamic range in the recording media, low coherent x-ray flux, and aberrations and diffraction limits in visible light reconstruction. We have addressed the recording limitations through the use of an undulator x-ray source and high-resolution photoresist recording media. For improved results in the readout and reconstruction steps, we have employed metal shadowing and transmission electron microscopy, along with numerical reconstruction techniques. We believe that this approach will allow holography to emerge as a practical method of high-resolution x-ray microscopy. 30 refs., 4 figs

  4. Progress in high-resolution x-ray holographic microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsen, C.; Kirz, J.; Howells, M.; McQuaid, K.; Rothman, S.; Feder, R.; Sayre, D.

    1987-07-01

    Among the various types of x-ray microscopes that have been demonstrated, the holographic microscope has had the largest gap between promise and performance. The difficulties of fabricating x-ray optical elements have led some to view holography as the most attractive method for obtaining the ultimate in high resolution x-ray micrographs; however, we know of no investigations prior to 1987 that clearly demonstrated submicron resolution in reconstructed images. Previous efforts suffered from problems such as limited resolution and dynamic range in the recording media, low coherent x-ray flux, and aberrations and diffraction limits in visible light reconstruction. We have addressed the recording limitations through the use of an undulator x-ray source and high-resolution photoresist recording media. For improved results in the readout and reconstruction steps, we have employed metal shadowing and transmission electron microscopy, along with numerical reconstruction techniques. We believe that this approach will allow holography to emerge as a practical method of high-resolution x-ray microscopy. 30 refs., 4 figs.

  5. A high resolution portable spectroscopy system

    International Nuclear Information System (INIS)

    Kulkarni, C.P.; Vaidya, P.P.; Paulson, M.; Bhatnagar, P.V.; Pande, S.S.; Padmini, S.

    2003-01-01

    Full text: This paper describes the system details of a High Resolution Portable Spectroscopy System (HRPSS) developed at Electronics Division, BARC. The system can be used for laboratory class, high-resolution nuclear spectroscopy applications. The HRPSS consists of a specially designed compact NIM bin, with built-in power supplies, accommodating a low power, high resolution MCA, and on-board embedded computer for spectrum building and communication. A NIM based spectroscopy amplifier and a HV module for detector bias are integrated (plug-in) in the bin. The system communicates with a host PC via a serial link. Along-with a laptop PC, and a portable HP-Ge detector, the HRPSS offers a laboratory class performance for portable applications

  6. Transmission electron microscopy physics of image formation and microanalysis

    CERN Document Server

    Reimer, Ludwig

    1993-01-01

    "Transmission Electron Microscopy" presents the theory of image and contrastformation, and the analytical modes in transmission electron microscopy Theprinciples of particle and wave optics of electrons are described Electron-specimen interactions are discussed for evaluating the theory of scattering and phase contrast Also analysed are the kinetical and dynamical theories of electron diffraction and their applications for crystal-structure determination and imaging of lattices and their defects X-ray microanalysis and electron energy-loss spectroscopy are treated as analytical methods The third edition includes a brief discussionof Schottky emission guns, some clarification of minor details, and references to the recent literature

  7. Electronic excitation of carbonyl sulphide (COS) by high-resolution vacuum ultraviolet photoabsorption and electron-impact spectroscopy in the energy region from 4 to 11 eV

    Energy Technology Data Exchange (ETDEWEB)

    Limão-Vieira, P., E-mail: plimaovieira@fct.unl.pt [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Department of Physics, Sophia University, Tokyo 102-8554 (Japan); Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Ferreira da Silva, F.; Almeida, D. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Hoshino, M.; Tanaka, H. [Department of Physics, Sophia University, Tokyo 102-8554 (Japan); Mogi, D. [Development and Marketing Department, New Products Development Division, Kanto Denka, Kogyo Co., Ltd., Chiyoda-ku, Tokyo 101-0063 (Japan); Tanioka, T. [Shibukawa Development Research Laboratory, New Products Development Division, Kanto Denka Kogyo Co., Ltd., Shibukawa City, Gunma 377-8513 (Japan); Mason, N. J. [Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Hoffmann, S. V. [ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Århus C (Denmark); Hubin-Franskin, M.-J.; Delwiche, J. [Départment de Chimie, Université de Liège, Institut de Chimie-Bât. B6C, allée de la Chimie 3, B-4000 Liège 1 (Belgium)

    2015-02-14

    The electronic state spectroscopy of carbonyl sulphide, COS, has been investigated using high resolution vacuum ultraviolet photoabsorption spectroscopy and electron energy loss spectroscopy in the energy range of 4.0–10.8 eV. The spectrum reveals several new features not previously reported in the literature. Vibronic structure has been observed, notably in the low energy absorption dipole forbidden band assigned to the (4π←3π) ({sup 1}Δ←{sup 1}Σ{sup +}) transition, with a new weak transition assigned to ({sup 1}Σ{sup −}←{sup 1}Σ{sup +}) reported here for the first time. The absolute optical oscillator strengths are determined for ground state to {sup 1}Σ{sup +} and {sup 1}Π transitions. Based on our recent measurements of differential cross sections for the optically allowed ({sup 1}Σ{sup +} and {sup 1}Π) transitions of COS by electron impact, the optical oscillator strength f{sub 0} value and integral cross sections (ICSs) are derived by applying a generalized oscillator strength analysis. Subsequently, ICSs predicted by the scaling are confirmed down to 60 eV in the intermediate energy region. The measured absolute photoabsorption cross sections have been used to calculate the photolysis lifetime of carbonyl sulphide in the upper stratosphere (20–50 km)

  8. Structural changes of Bi sub 1. 8 Sr sub 2 (Ca sub 1 minus x Y sub x )Cu sub 2. 2 O sub z ceramics with yttrium content studied by electron diffraction and high-resolution electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Onozuka, T.; Iwabuchi, Y.; Fukase, T. (Institute for Materials Research, Tohoku University, Sendai 980, Japan (JP)); Sato, H. (School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907 (USA)); Mitchell, T.E. (Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (USA))

    1991-06-01

    The mode of the incommensurate modulation in the {ital b} direction of the Bi{sub 1.8}Sr{sub 2}(Ca{sub 1{minus}{ital x}}Y{sub {ital x}})Cu{sub 2.2}O{sub {ital z}} (0.05{lt}{ital x}{lt}0.75) system is investigated by means of electron diffraction and high-resolution lattice imaging. The change of period of the long-period structure with {ital x} is found to be basically due to the mixing ratio of domains of two modulation periods with {ital b}=4.5{ital b}{sub 0} and 5{ital b}{sub 0} or 4.5{ital b}{sub 0} and 4{ital b}{sub 0}, thus creating periods of {ital b}=4.75{ital b}{sub 0--}4.0{ital b}{sub 0}. The fundamental orthorhombic lattice has dimensions of {ital a}{congruent}{ital b}{congruent}{ital b}{sub 0} (0.54 nm) and {ital c}{congruent}{ital c}{sub 0} (3.1 nm). The change of the mixing mode from one to the other mentioned above occurs just in the yttrium concentration range, 0.45{lt}{ital x}{lt}0.65, which also corresponds to the superconductor (metallic)-to-semiconductor transition boundary. The mixing modes of the domains are directly recorded as a contrast modulation with half periods, 4.5{ital b}{sub 0}/2 and 5{ital b}{sub 0}/2 or 4.5{ital b}{sub 0}/2 and 4{ital b}{sub 0}/2 in high-resolution lattice images. These images are reproduced well by a multislice computer-simulation technique.

  9. Transmission electron microscopy of nanostructures synthesized by laser and charged particle beam interaction with materials

    International Nuclear Information System (INIS)

    Dey, G. K.

    2011-01-01

    Transmission Electron Microscopy (TEM), because of its ability to image atomic arrangements directly and its ability to give spectroscopic information at similar resolution has emerged as a very powerful tool for understanding the structure of materials at atomic level. TEM has been particularly useful in resolving the interface structures in materials. This form of microscopy is very suitable for resolving the structure and defects in ultrafine microstructures such as those of the nanocrystalline phases. After a brief description of the different characterization abilities of the aberration corrected transmission electron microscope, this presentation describes the results of TEM investigations on nanocrystalline microstructures generated by laser materials interaction and due to interaction of electrons and ions with materials. Excimer laser has become an attractive choice for new and precision application for ablation and deposition in recent times. In this work, a KrF excimer laser having 30 ns pulse width and 600 mJ energy at source has been used to deposit zirconia on Zr-base alloy in order to explore the ability of the thin oxide film to act as a diffusion barrier to hydrogen ingress into the alloy. It has been found that the variation in pressure by an order of three has resulted in maximum influence on the roughness of the laser deposited oxide film that has not been possible to achieve by other parameters within the range of the instrument. Present study has also indicated an interrelation among the roughness, adherence and the film-thickness, where the last one is indicated by the XPS study. Transmission electron microscopy was carried out to study the size, size distribution and defects in the deposited film. Nanocrystalline phases generated by interaction of electron and ion irradiation of Zr based alloys; Ni based alloys and Fe based alloys have been examined in detail by conventional and high resolution transmission electron microscopy. Results of

  10. Investigation by high resolution electron spectroscopy of the helium-like 3lnl' Rydberg series in double capture processes at low collision velocity: auto transfer to Rydberg states and electron stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, A.; Moretto-Capelle, P.; Gonzalez, A.; Benhenni, M. (Toulouse-3 Univ., 31 (France)); Bachau, H.; Sanchez, I. (Bordeaux-1 Univ., 33 - Talence (France). Lab. des Collisions Atomiques)

    1994-09-28

    A high resolution electron spectrometry of the (3lnl') Ryberg series populated in N[sup 7+] + He and Ne[sup 10+] + He collisions at 10 q keV, 10[sup o] allows us to observe, for the first time by this method, two post-collisional effects. First, it is found with nitrogen ions that, when n increases from n = 4 to 9, the L-distribution peaks more and more on the high angular momentum states. This is qualitatively understood as a Stark deformation of the Rydberg orbit by the Coulomb field of the receding ion. Also, in the n range where the double capture process populates symmetrical 4l4l' states (n>9), an enhancement of the intensities of the 3lnl' Rydberg lines is observed for both collisonal systems. This is thought to be a signature of the so-called auto transfer to Rydberg states effect. The transfer of population from the 3l4l' to the 3lnl' states is found to be favoured against a direct autoionization of these 4l4l' states into the n = 2 continuum. These experimental findings together with preliminary spectroscopic calculations concerning the configuration interaction of the Ne[sup 8+] (4l4l') states with the Ne[sup 8+](3lnl') Rydberg series are also discussed within the context of the electron stabilization which follows a double capture. (Author).

  11. Investigation by high resolution electron spectroscopy of the helium-like 3lnl' Rydberg series in double capture processes at low collision velocity: auto transfer to Rydberg states and electron stabilization

    International Nuclear Information System (INIS)

    Bordenave-Montesquieu, A.; Moretto-Capelle, P.; Gonzalez, A.; Benhenni, M.; Bachau, H.; Sanchez, I.

    1994-01-01

    A high resolution electron spectrometry of the (3lnl') Ryberg series populated in N 7+ + He and Ne 10+ + He collisions at 10 q keV, 10 o allows us to observe, for the first time by this method, two post-collisional effects. First, it is found with nitrogen ions that, when n increases from n = 4 to 9, the L-distribution peaks more and more on the high angular momentum states. This is qualitatively understood as a Stark deformation of the Rydberg orbit by the Coulomb field of the receding ion. Also, in the n range where the double capture process populates symmetrical 4l4l' states (n>9), an enhancement of the intensities of the 3lnl' Rydberg lines is observed for both collisonal systems. This is thought to be a signature of the so-called auto transfer to Rydberg states effect. The transfer of population from the 3l4l' to the 3lnl' states is found to be favoured against a direct autoionization of these 4l4l' states into the n = 2 continuum. These experimental findings together with preliminary spectroscopic calculations concerning the configuration interaction of the Ne 8+ (4l4l') states with the Ne 8+ (3lnl') Rydberg series are also discussed within the context of the electron stabilization which follows a double capture. (Author)

  12. Quantitative Scanning Transmission Electron Microscopy of Electronic and Nanostructured Materials

    Science.gov (United States)

    Yankovich, Andrew B.

    Electronic and nanostructured materials have been investigated using advanced scanning transmission electron microscopy (STEM) techniques. The first topic is the microstructure of Ga and Sb-doped ZnO. Ga-doped ZnO is a candidate transparent conducting oxide material. The microstructure of GZO thin films grown by MBE under different growth conditions and different substrates were examined using various electron microscopy (EM) techniques. The microstructure, prevalent defects, and polarity in these films strongly depend on the growth conditions and substrate. Sb-doped ZnO nanowires have been shown to be the first route to stable p-type ZnO. Using Z-contrast STEM, I have showed that an unusual microstructure of Sb-decorated head-to-head inversion domain boundaries and internal voids contain all the Sb in the nanowires and cause the p-type conduction. InGaN thin films and InGaN / GaN quantum wells (QW) for light emitting diodes are the second topic. Low-dose Z-contrast STEM, PACBED, and EDS on InGaN QW LED structures grown by MOCVD show no evidence for nanoscale composition variations, contradicting previous reports. In addition, a new extended defect in GaN and InGaN was discovered. The defect consists of a faceted pyramid-shaped void that produces a threading dislocation along the [0001] growth direction, and is likely caused by carbon contamination during growth. Non-rigid registration (NRR) and high-precision STEM of nanoparticles is the final topic. NRR is a new image processing technique that corrects distortions arising from the serial nature of STEM acquisition that previously limited the precision of locating atomic columns and counting the number of atoms in images. NRR was used to demonstrate sub-picometer precision in STEM images of single crystal Si and GaN, the best achieved in EM. NRR was used to measure the atomic surface structure of Pt nanoacatalysts and Au nanoparticles, which revealed new bond length variation phenomenon of surface atoms. In

  13. Complex band structure and electronic transmission eigenchannels

    DEFF Research Database (Denmark)

    Jensen, Anders; Strange, Mikkel; Smidstrup, Soren

    2017-01-01

    and complex band structure, in this case individual eigenchannel transmissions and different complex bands. We present calculations of decay constants for the two most conductive states as determined by complex band structure and standard DFT Landauer transport calculations for one semi-conductor and two...

  14. Multiple double cross-section transmission electron microscope sample preparation of specific sub-10 nm diameter Si nanowire devices.

    Science.gov (United States)

    Gignac, Lynne M; Mittal, Surbhi; Bangsaruntip, Sarunya; Cohen, Guy M; Sleight, Jeffrey W

    2011-12-01

    The ability to prepare multiple cross-section transmission electron microscope (XTEM) samples from one XTEM sample of specific sub-10 nm features was demonstrated. Sub-10 nm diameter Si nanowire (NW) devices were initially cross-sectioned using a dual-beam focused ion beam system in a direction running parallel to the device channel. From this XTEM sample, both low- and high-resolution transmission electron microscope (TEM) images were obtained from six separate, specific site Si NW devices. The XTEM sample was then re-sectioned in four separate locations in a direction perpendicular to the device channel: 90° from the original XTEM sample direction. Three of the four XTEM samples were successfully sectioned in the gate region of the device. From these three samples, low- and high-resolution TEM images of the Si NW were taken and measurements of the NW diameters were obtained. This technique demonstrated the ability to obtain high-resolution TEM images in directions 90° from one another of multiple, specific sub-10 nm features that were spaced 1.1 μm apart.

  15. Detecting and locating light atoms from high-resolution STEM images : The quest for a single optimal design

    NARCIS (Netherlands)

    Gonnissen, J; De Backer, A; den Dekker, A.J.; Sijbers, J.; Van Aert, S.

    2016-01-01

    In the present paper, the optimal detector design is investigated for both detecting and locating light atoms from high resolution scanning transmission electron microscopy (HR STEM) images. The principles of detection theory are used to quantify the probability of error for the detection of

  16. Direct band gap measurement of Cu(In,Ga)(Se,S)2 thin films using high-resolution reflection electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Heo, Sung; Lee, Hyung-Ik; Park, Jong-Bong; Ko, Dong-Su; Chung, JaeGwan; Kim, KiHong; Kim, Seong Heon; Yun, Dong-Jin; Ham, YongNam; Park, Gyeong Su; Song, Taewon; Lee, Dongho; Nam, Junggyu; Kang, Hee Jae; Choi, Pyung-Ho; Choi, Byoung-Deog

    2015-01-01

    To investigate the band gap profile of Cu(In 1−x ,Ga x )(Se 1−y S y ) 2 of various compositions, we measured the band gap profile directly as a function of in-depth using high-resolution reflection energy loss spectroscopy (HR-REELS), which was compared with the band gap profile calculated based on the auger depth profile. The band gap profile is a double-graded band gap as a function of in-depth. The calculated band gap obtained from the auger depth profile seems to be larger than that by HR-REELS. Calculated band gaps are to measure the average band gap of the spatially different varying compositions with respect to considering its void fraction. But, the results obtained using HR-REELS are to be affected by the low band gap (i.e., out of void) rather than large one (i.e., near void). Our findings suggest an analytical method to directly determine the band gap profile as function of in-depth

  17. Direct band gap measurement of Cu(In,Ga)(Se,S){sub 2} thin films using high-resolution reflection electron energy loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Sung [Analytical Engineering Group, Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803 (Korea, Republic of); College of Information and Communication Engineering, Sungkyunkwan University, Cheoncheon-dong 300, Jangan-gu, Suwon 440-746 (Korea, Republic of); Lee, Hyung-Ik; Park, Jong-Bong; Ko, Dong-Su; Chung, JaeGwan; Kim, KiHong; Kim, Seong Heon; Yun, Dong-Jin; Ham, YongNam; Park, Gyeong Su [Analytical Engineering Group, Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803 (Korea, Republic of); Song, Taewon [Energy lab, Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803 (Korea, Republic of); Lee, Dongho, E-mail: dhlee0333@gmail.com; Nam, Junggyu [PV Development Team, Energy Solution Business Division, Samsung SDI, 467 Beonyeong-ro, Cheonan-si, Chungcheongnam-do 331-330 (Korea, Republic of); Kang, Hee Jae [Department of Physics, Chungbuk National University, Gaesin-dong, Heungdeok-gu, Cheongju, 361-763 (Korea, Republic of); Choi, Pyung-Ho; Choi, Byoung-Deog, E-mail: bdchoi@skku.edu [College of Information and Communication Engineering, Sungkyunkwan University, Cheoncheon-dong 300, Jangan-gu, Suwon 440-746 (Korea, Republic of)

    2015-06-29

    To investigate the band gap profile of Cu(In{sub 1−x},Ga{sub x})(Se{sub 1−y}S{sub y}){sub 2} of various compositions, we measured the band gap profile directly as a function of in-depth using high-resolution reflection energy loss spectroscopy (HR-REELS), which was compared with the band gap profile calculated based on the auger depth profile. The band gap profile is a double-graded band gap as a function of in-depth. The calculated band gap obtained from the auger depth profile seems to be larger than that by HR-REELS. Calculated band gaps are to measure the average band gap of the spatially different varying compositions with respect to considering its void fraction. But, the results obtained using HR-REELS are to be affected by the low band gap (i.e., out of void) rather than large one (i.e., near void). Our findings suggest an analytical method to directly determine the band gap profile as function of in-depth.

  18. Three-Dimensional scanning transmission electron microscopy of biological specimens

    KAUST Repository

    De Jonge, Niels; Sougrat, Rachid; Northan, Brian M.; Pennycook, Stephen J.

    2010-01-01

    A three-dimensional (3D) reconstruction of the cytoskeleton and a clathrin-coated pit in mammalian cells has been achieved from a focal-series of images recorded in an aberration-corrected scanning transmission electron microscope (STEM

  19. Disclosure of domain structure in cubic CaxZr1-xO2-x, 0x15 ≤ x ≤ 0x20, by Talbot image enhancement of high-resolution electron micrographs

    International Nuclear Information System (INIS)

    Rossell, H.J.; Wilson, I.J.; Sellar, J.R.

    1991-01-01

    High-resolution electron microscope images have been recorded of several cystalline samples of calcia-stabilized zirconia (Ca-CSZ) and of the fluorite-related superstructure phase φ 1 (CaZr 4 O 9 ). The contrast of the CSZ images has been enhanced markedly by the light-optical Talbot self-imaging technique. Is is demonstrated that the CSZ crystals contain a coherent dispersion of microdomains approximately 30 A in diameter, and that the structure of the microdomains is that of φ 1 . (orig.)

  20. Berkeley High-Resolution Ball

    International Nuclear Information System (INIS)

    Diamond, R.M.

    1984-10-01

    Criteria for a high-resolution γ-ray system are discussed. Desirable properties are high resolution, good response function, and moderate solid angle so as to achieve not only double- but triple-coincidences with good statistics. The Berkeley High-Resolution Ball involved the first use of bismuth germanate (BGO) for anti-Compton shield for Ge detectors. The resulting compact shield permitted rather close packing of 21 detectors around a target. In addition, a small central BGO ball gives the total γ-ray energy and multiplicity, as well as the angular pattern of the γ rays. The 21-detector array is nearly complete, and the central ball has been designed, but not yet constructed. First results taken with 9 detector modules are shown for the nucleus 156 Er. The complex decay scheme indicates a transition from collective rotation (prolate shape) to single- particle states (possibly oblate) near spin 30 h, and has other interesting features

  1. Calculation of electron transmission through aluminium foil

    International Nuclear Information System (INIS)

    Abroyan, M.A.; Mel'ker, A.I.; Mikhajlin, A.I.; Sirotinkin, V.V.; Tokmakov, I.L.

    1987-01-01

    Calculated by Monte Carlo method energy and angular distributions of electrons transmitted through aluminium foil with 50 μm thickness are presented. 200-500 electron energy ranges and angles of electron incidence on foil from 0 to 40 deg C are considered. That allows to use results for more universal accelerator group, for example, for accelerators with scanning beam used in industry. The received values of angular and energy characteristics allow to increase essentially estimation accuracy of accelerator extraction devices and dose distribution on irradiating item

  2. High voltage/high resolution studies of metal and semiconductor interfaces

    International Nuclear Information System (INIS)

    Westmacott, K.H.; Dahmen, U.

    1989-11-01

    The application of high resolution transmission electron microscopy to the study of homo- or hetero-phase interface structures requires specimens that meet stringent criteria. In some systems the necessary geometric imaging conditions are established naturally, thus greatly simplifying the analysis. This is illustrated for a diamond-hexagonal/diamond-cubic interface in deformed silicon, a Σ99 tilt boundary in a pure aluminum bicrystal, and a germanium precipitate in an aluminum matrix. 13 refs., 5 figs

  3. Angularly-selective transmission imaging in a scanning electron microscope.

    Science.gov (United States)

    Holm, Jason; Keller, Robert R

    2016-08-01

    This work presents recent advances in transmission scanning electron microscopy (t-SEM) imaging control capabilities. A modular aperture system and a cantilever-style sample holder that enable comprehensive angular selectivity of forward-scattered electrons are described. When combined with a commercially available solid-state transmission detector having only basic bright-field and dark-field imaging capabilities, the advances described here enable numerous transmission imaging modes. Several examples are provided that demonstrate how contrast arising from diffraction to mass-thickness can be obtained. Unanticipated image contrast at some imaging conditions is also observed and addressed. Published by Elsevier B.V.

  4. High resolution metric imaging payload

    Science.gov (United States)

    Delclaud, Y.

    2017-11-01

    Alcatel Space Industries has become Europe's leader in the field of high and very high resolution optical payloads, in the frame work of earth observation system able to provide military government with metric images from space. This leadership allowed ALCATEL to propose for the export market, within a French collaboration frame, a complete space based system for metric observation.

  5. Transmission electron microscopy investigation of interfaces in a two-phase TiAl alloy

    Science.gov (United States)

    Mahon, G. J.; Howe, J. M.

    1990-06-01

    The atomic structures of the γ/α2 and γ/γT interfaces in a TiAl alloy were investigated using conventional and high-resolution transmission electron microscopy (TEM) in order to understand the growth mechanisms and deformation behavior of the two-phase alloy. The results show that the α2 plates grow from the γ phase by the migration of a/6 partial dislocation ledges across the faces and that the γ/α2 interface usually contains closely spaced arrays of interfacial dislocations. Deformation twins cut through both γ twin boundaries and α2 plates during deformation, although slip of twinning c slocations through α2 appears to be a difficult process. Both the γ/α2 and γ/γT interfaces can be imaged and modeled at the atomic level, although slight crystal and/or beam tilt can complicate image interpretation.

  6. Use of atomic force microscopy and transmission electron microscopy for correlative studies of bacterial capsules.

    Science.gov (United States)

    Stukalov, Oleg; Korenevsky, Anton; Beveridge, Terry J; Dutcher, John R

    2008-09-01

    Bacteria can possess an outermost assembly of polysaccharide molecules, a capsule, which is attached to their cell wall. We have used two complementary, high-resolution microscopy techniques, atomic force microscopy (AFM) and transmission electron microscopy (TEM), to study bacterial capsules of four different gram-negative bacterial strains: Escherichia coli K30, Pseudomonas aeruginosa FRD1, Shewanella oneidensis MR-4, and Geobacter sulfurreducens PCA. TEM analysis of bacterial cells using different preparative techniques (whole-cell mounts, conventional embeddings, and freeze-substitution) revealed capsules for some but not all of the strains. In contrast, the use of AFM allowed the unambiguous identification of the presence of capsules on all strains used in the present study, including those that were shown by TEM to be not encapsulated. In addition, the use of AFM phase imaging allowed the visualization of the bacterial cell within the capsule, with a depth sensitivity that decreased with increasing tapping frequency.

  7. Elemental distribution imaging by energy-filtering transmission electron microscopy (EFTEM) and its applications

    International Nuclear Information System (INIS)

    Kurata, Hiroki

    1996-01-01

    EFTEM is new microscopy with the object of visualizing high resolution quantitative elemental distribution. The measurement principles and the present state of EFTEM studies are explained by the examples of measurement of the elemental distributions. EFTEM is a combination of the transmission electron microscope with the electron energy loss spectroscopy (EFLS). EFTEM method sets the slit in the specific energy field and put the electron passing the slit back in the microscopic image. The qualitative elemental analysis is obtained by observing the position of the absorption end of core electronic excitation spectrum and the quantitative one by determining the core electronic excitation strength of the specific atom depend on filtering with energy selector slit. The binding state and the local structure in the neighborhood of excited atom is determined by the fine structure of absorption end. By the chemical mapping method, the distribution image of chemical binding state is visualized by the imaging chemical map obtained by filtering the specific peak strength of fine structure with the narrow energy selector slit. The fine powder of lead chromate (PbCrO 4 ) covered with silica glass was shown as a typical example of the elemental distribution image of core electronic excitation spectrum. The quantitative analysis method of elemental distribution image is explained. The possibility of single atom analysis at nanometer was shown by the example of nanotube observed by EFTEM. (S.Y.)

  8. The Titan Environmental Transmission Electron Microscope

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; Wagner, Jakob Birkedal; Jinschek, Jörg R.

    2009-01-01

    University of Denmark (DTU) provides a unique combination of techniques for studying materials of interest to the catalytic as well as the electronics and other communities [5]. DTU’s ETEM is based on the FEI Titan platform providing ultrahigh microscope stability pushing the imaging resolution into the sub...

  9. Exploring the environmental transmission electron microscope

    DEFF Research Database (Denmark)

    Wagner, Jakob B.; Cavalca, Filippo; Damsgaard, Christian D.

    2012-01-01

    of the opportunities that the environmental TEM (ETEM) offers when combined with other in situ techniques will be explored, directly in the microscope, by combining electron-based and photon-based techniques and phenomena. In addition, application of adjacent setups using sophisticated transfer methods...

  10. Scanning transmission low-energy electron microscopy

    Czech Academy of Sciences Publication Activity Database

    Müllerová, Ilona; Hovorka, Miloš; Konvalina, Ivo; Unčovský, M.; Frank, Luděk

    2011-01-01

    Roč. 55, č. 4 (2011), 2:1-6 ISSN 0018-8646 R&D Projects: GA AV ČR IAA100650902; GA MŠk ED0017/01/01 Institutional research plan: CEZ:AV0Z20650511 Keywords : TEM * STEM * SEM Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.723, year: 2011

  11. Long distance electron transmission in marine sediment

    DEFF Research Database (Denmark)

    Risgaard-Petersen, Nils; Nielsen, Lars Peter

    processes leads to formation of electrical fields, which modifies ion transport. The local proton producing and proton consuming half reactions induces pH extremes that accelerate dissolution of iron sul-phides and calcium carbonates in anoxic layers and promotes the formation of Mg-calcite and iron oxides......Geochemical observations in marine sediment have recently shown that electric currents may intimately couple spatially separated biogeochemical processes like oxygen reduction at the sediment surface and hydrogen sul-phide oxidation in anoxic layers centimeters below 1. Further experimental studies...... suggest that the electron conductance is mediated by microorgan-isms. The spatial separation of electron and proton donors and acceptors has major impacts on element cycling by redox processes, pH balances, mineral dissolution/precipitations, and electromigration of ions. The sepa-ration of redox...

  12. High-Resolution Characterization of UMo Alloy Microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Devaraj, Arun [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kovarik, Libor [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Joshi, Vineet V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jana, Saumyadeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Manandhar, Sandeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Arey, Bruce W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-11-30

    This report highlights the capabilities and procedure for high-resolution characterization of UMo fuels in PNNL. Uranium-molybdenum (UMo) fuel processing steps, from casting to forming final fuel, directly affect the microstructure of the fuel, which in turn dictates the in-reactor performance of the fuel under irradiation. In order to understand the influence of processing on UMo microstructure, microstructure characterization techniques are necessary. Higher-resolution characterization techniques like transmission electron microscopy (TEM) and atom probe tomography (APT) are needed to interrogate the details of the microstructure. The findings from TEM and APT are also directly beneficial for developing predictive multiscale modeling tools that can predict the microstructure as a function of process parameters. This report provides background on focused-ion-beam–based TEM and APT sample preparation, TEM and APT analysis procedures, and the unique information achievable through such advanced characterization capabilities for UMo fuels, from a fuel fabrication capability viewpoint.

  13. High resolution ultrastructure imaging of fractures in human dental tissues

    Directory of Open Access Journals (Sweden)

    Tan Sui

    2014-01-01

    Full Text Available Human dental hard tissues are dentine, cementum, and enamel. These are hydrated mineralised composite tissues with a hierarchical structure and versatile thermo-mechanical properties. The hierarchical structure of dentine and enamel was imaged by transmission electron microscopy (TEM of samples prepared by focused ion beam (FIB milling. High resolution TEM was carried out in the vicinity of a crack tip in dentine. An intricate “random weave” pattern of hydroxyapatile crystallites was observed and this provided a possible explanation for toughening of the mineralized dentine tissue at the nano-scale. The results reported here provide the basis for improved understanding of the relationship between the multi-scale nature and the mechanical properties of hierarchically structured biomaterials, and will also be useful for the development of better prosthetic and dental restorative materials.

  14. High-resolution electron spectroscopy of the 1s23lnl' Be-like series in oxygen and neon. Test of theoretical data: I. Experimental method and theoretical background

    International Nuclear Information System (INIS)

    Bordenave-Montesquieu, A; Moretto-Capelle, P; Bordenave-Montesquieu, D

    2003-01-01

    A complete and accurate experimental test of theoretical spectroscopic data sets (state positions, lifetimes) available for the n = 3-5 terms of the 1s 2 3lnl' Rydberg series of oxygen and neon ions is presented in a series of two papers. This result was achieved by fitting our high resolution electron spectra with post-collisional lineshapes calculated with the help of these spectroscopic data. In this paper the method which has been developed for this fitting procedure is explained. In addition, as a first test, a comparison of all the available calculated spectroscopic data is presented and discussed. Strong deviations of transition energies and decay lifetimes are observed in many cases. Best data are selected in the following companion paper through a quantitative comparison with our experimental electron spectra

  15. High-resolution electron spectroscopy of the 1s{sup 2}3lnl' Be-like series in oxygen and neon. Test of theoretical data: I. Experimental method and theoretical background

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, A; Moretto-Capelle, P; Bordenave-Montesquieu, D [Laboratoire CAR-IRSAMC, UMR 5589 CNRS - Universite Paul Sabatier, 31062 Toulouse (France)

    2003-01-14

    A complete and accurate experimental test of theoretical spectroscopic data sets (state positions, lifetimes) available for the n = 3-5 terms of the 1s{sup 2}3lnl' Rydberg series of oxygen and neon ions is presented in a series of two papers. This result was achieved by fitting our high resolution electron spectra with post-collisional lineshapes calculated with the help of these spectroscopic data. In this paper the method which has been developed for this fitting procedure is explained. In addition, as a first test, a comparison of all the available calculated spectroscopic data is presented and discussed. Strong deviations of transition energies and decay lifetimes are observed in many cases. Best data are selected in the following companion paper through a quantitative comparison with our experimental electron spectra.

  16. Structure analysis of OmpC, one of the major proteins in the outer membrane of E. coli, by high resolution electron microscopy

    International Nuclear Information System (INIS)

    Chang, C.F.

    1983-07-01

    This dissertation is concerned with the structure analysis of a pore-forming membrane protein, OmpC, which is one of the major proteins in the outer membrane of Escherichia coli. In order to obtain structural information it was necessary to develop a suitable technique for preparing two-dimensional crystalline arrays of this membrane protein in an unfixed, unstained and hydrated condition. Electron micrographs were recorded at exposures of less than 5 electrons/A 2 in order to avoid severe radiation damage. The resulting images were crystallographically averaged, in order to overcome the statistical limitations associated with the low electron exposures. The resulting images, which extend to a resolution of approx. 13.5 A, lend themselves to a natural interpretation that is consistent with the mass density of protein, water and lipid, prior data from 2-D and 3-D structure studies of negatively stained specimens at approx. = 20 A resolution, and published spectroscopic data on the peptide chain secondary structure

  17. High Resolution Displays Using NCAP Liquid Crystals

    Science.gov (United States)

    Macknick, A. Brian; Jones, Phil; White, Larry

    1989-07-01

    Nematic curvilinear aligned phase (NCAP) liquid crystals have been found useful for high information content video displays. NCAP materials are liquid crystals which have been encapsulated in a polymer matrix and which have a light transmission which is variable with applied electric fields. Because NCAP materials do not require polarizers, their on-state transmission is substantially better than twisted nematic cells. All dimensional tolerances are locked in during the encapsulation process and hence there are no critical sealing or spacing issues. By controlling the polymer/liquid crystal morphology, switching speeds of NCAP materials have been significantly improved over twisted nematic systems. Recent work has combined active matrix addressing with NCAP materials. Active matrices, such as thin film transistors, have given displays of high resolution. The paper will discuss the advantages of NCAP materials specifically designed for operation at video rates on transistor arrays; applications for both backlit and projection displays will be discussed.

  18. Transmission electron microscopy and diffractometry of materials

    CERN Document Server

    Fultz, Brent

    2001-01-01

    This book teaches graduate students the concepts of trans- mission electron microscopy (TEM) and x-ray diffractometry (XRD) that are important for the characterization of materi- als. It emphasizes themes common to both techniques, such as scattering from atoms and the formation and analysis of dif- fraction patterns. It also describes unique aspects of each technique, especially imaging and spectroscopy in the TEM. The textbook thoroughly develops both introductory and ad- vanced-level material, using over 400 accompanying illustra- tions. Problems are provided at the end of each chapter to reinforce key concepts. Simple citatioins of rules are avoi- ded as much as possible, and both practical and theoretical issues are explained in detail. The book can be used as both an introductory and advanced-level graduate text since sec- tions/chapters are sorted according to difficulty and grou- ped for use in quarter and semester courses on TEM and XRD.

  19. First test results from the Front-End Board with Cyclone V as a test high-resolution platform for the Auger-Beyond-2015 Front End Electronics

    Energy Technology Data Exchange (ETDEWEB)

    Szadkowski, Zbigniew [University of Lodz, Department of Physics and Applied Informatics, Faculty of High-Energy Astrophysics, 90-236 Lodz, Pomorska 149, (Poland)

    2015-07-01

    The paper presents the first results from the Front- End Board (FEB) with the biggest Cyclone{sup R} V E FPGA 5CEFA9F31I7N, supporting 8 channels sampled up to 250 MSps at 14-bit resolution. Considered sampling for the SD is 120 MSps, however, the FEB has been developed with external anti-aliasing filters to keep a maximal flexibility. Six channels are targeted to the SD, two the rest for other experiments like: Auger Engineering Radio Array and additional muon counters. More channels and higher sampling generate larger size of registered events. We used the standard radio channel for a radio transmission from the detectors to the Central Data Acquisition Station (CDAS) to avoid at present a significant modification of a software in both sides: the detector and the CDAS (planned in a future for a final design). Seven FEBs have been deployed in the test detectors on a dedicated Engineering Array in a hexagon. Several variants of the FPGA code were tested for 120, 160, 200 and even 240 MSps DAQ. Tests confirmed a stability and reliability of the FEB design in real pampas conditions with more than 40 deg. C daily temperature variation and a strong sun exposition with a limited power budget only from a single solar panel. (authors)

  20. Simulation of loss electron in vacuum magnetically insulated transmission lines

    International Nuclear Information System (INIS)

    Zhang Pengfei; Li Yongdong; Liu Chunliang; Wang Hongguang; Guo Fan; Yang Hailiang; Qiu Aici; Su Zhaofeng; Sun Jianfeng; Sun Jiang; Gao Yi

    2011-01-01

    In the beginning of magnetic insulated period, loss electron in coaxial vacuum magnetically insulated transmission line (MITL) strikes anode and the bremsstrahlung photons are generated in the mean time. Based on the self-limited flow model, velocity in direction of energy transport, energy spectrum and angular distribution of loss electron are simulated by PIC code, energy spectrum of bremsstrahlung photons as well calculated though Monte Carlo method. Computational results show that the velocity of loss electron is less than 2.998 x 108 m/s, the angular excursion of electron is not much in a board extent of energy spectrum. These results show an indirect diagnosis of vacuum insulted transmission line working status based on loss electron bremsstrahlung. (authors)

  1. Analysis on electronic control unit of continuously variable transmission

    Science.gov (United States)

    Cao, Shuanggui

    Continuously variable transmission system can ensure that the engine work along the line of best fuel economy, improve fuel economy, save fuel and reduce harmful gas emissions. At the same time, continuously variable transmission allows the vehicle speed is more smooth and improves the ride comfort. Although the CVT technology has made great development, but there are many shortcomings in the CVT. The CVT system of ordinary vehicles now is still low efficiency, poor starting performance, low transmission power, and is not ideal controlling, high cost and other issues. Therefore, many scholars began to study some new type of continuously variable transmission. The transmission system with electronic systems control can achieve automatic control of power transmission, give full play to the characteristics of the engine to achieve optimal control of powertrain, so the vehicle is always traveling around the best condition. Electronic control unit is composed of the core processor, input and output circuit module and other auxiliary circuit module. Input module collects and process many signals sent by sensor and , such as throttle angle, brake signals, engine speed signal, speed signal of input and output shaft of transmission, manual shift signals, mode selection signals, gear position signal and the speed ratio signal, so as to provide its corresponding processing for the controller core.

  2. Ultra-high resolution protein crystallography

    International Nuclear Information System (INIS)

    Takeda, Kazuki; Hirano, Yu; Miki, Kunio

    2010-01-01

    Many protein structures have been determined by X-ray crystallography and deposited with the Protein Data Bank. However, these structures at usual resolution (1.5< d<3.0 A) are insufficient in their precision and quantity for elucidating the molecular mechanism of protein functions directly from structural information. Several studies at ultra-high resolution (d<0.8 A) have been performed with synchrotron radiation in the last decade. The highest resolution of the protein crystals was achieved at 0.54 A resolution for a small protein, crambin. In such high resolution crystals, almost all of hydrogen atoms of proteins and some hydrogen atoms of bound water molecules are experimentally observed. In addition, outer-shell electrons of proteins can be analyzed by the multipole refinement procedure. However, the influence of X-rays should be precisely estimated in order to derive meaningful information from the crystallographic results. In this review, we summarize refinement procedures, current status and perspectives for ultra high resolution protein crystallography. (author)

  3. High-resolution spectroscopy in superfluid helium droplets. Investigation of vibrational fine structures in electronic spectra of phthalocyanine and porphyrin derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Riechers, Ricarda Eva Friederike Elisabeth

    2011-03-22

    Since a considerably large variety of substituted compounds is commercially available and the electronic excitation spectra fit well into the spectral range covered by the continuous wave dye laser used for this study several porphyrin and phthalocyanine derivatives substituted with different types and numbers of alkyl and aryl groups were chosen as molecular probes. Recording fluorescence excitation and dispersed emission spectra revealed exclusively sharp transitions for all species. A change of the molecule's electrostatic moments, primarily and most effectively, a change of the molecular dipole moment regarding both magnitude and orientation, was identified as the main contribution for line broadening effects. Apart from the sharp lines presented in their fluorescence excitation spectra, the phthalocyanine derivatives investigated for this study, namely chloro-aluminium-phthalocyanine (AlClPc) and tetra-tertbutyl-phthalocyanine (TTBPc), exhibited more than one emission spectrum.

  4. High-resolution spectroscopy in superfluid helium droplets. Investigation of vibrational fine structures in electronic spectra of phthalocyanine and porphyrin derivatives

    International Nuclear Information System (INIS)

    Riechers, Ricarda Eva Friederike Elisabeth

    2011-01-01

    Since a considerably large variety of substituted compounds is commercially available and the electronic excitation spectra fit well into the spectral range covered by the continuous wave dye laser used for this study several porphyrin and phthalocyanine derivatives substituted with different types and numbers of alkyl and aryl groups were chosen as molecular probes. Recording fluorescence excitation and dispersed emission spectra revealed exclusively sharp transitions for all species. A change of the molecule's electrostatic moments, primarily and most effectively, a change of the molecular dipole moment regarding both magnitude and orientation, was identified as the main contribution for line broadening effects. Apart from the sharp lines presented in their fluorescence excitation spectra, the phthalocyanine derivatives investigated for this study, namely chloro-aluminium-phthalocyanine (AlClPc) and tetra-tertbutyl-phthalocyanine (TTBPc), exhibited more than one emission spectrum.

  5. Processing scarce biological samples for light and transmission electron microscopy

    Directory of Open Access Journals (Sweden)

    P Taupin

    2008-06-01

    Full Text Available Light microscopy (LM and transmission electron microscopy (TEM aim at understanding the relationship structure-function. With advances in biology, isolation and purification of scarce populations of cells or subcellular structures may not lead to enough biological material, for processing for LM and TEM. A protocol for preparation of scarce biological samples is presented. It is based on pre-embedding the biological samples, suspensions or pellets, in bovine serum albumin (BSA and bis-acrylamide (BA, cross-linked and polymerized. This preparation provides a simple and reproducible technique to process biological materials, present in limited quantities that can not be amplified, for light and transmission electron microscopy.

  6. Development of the Atomic-Resolution Environmental Transmission Electron Microscope

    DEFF Research Database (Denmark)

    Gai, Pratibha L.; Boyes, Edward D.; Yoshida, Kenta

    2016-01-01

    The development of the novel atomic-resolution environmental transmission electron microscope (atomic-resolution ETEM) for directly probing dynamic gas–solid reactions in situ at the atomic level under controlled reaction conditions consisting of gas environment and elevated temperatures is descr......The development of the novel atomic-resolution environmental transmission electron microscope (atomic-resolution ETEM) for directly probing dynamic gas–solid reactions in situ at the atomic level under controlled reaction conditions consisting of gas environment and elevated temperatures...... is used to study steels, graphene, nanowires, etc. In this chapter, the experimental setup of the microscope column and its peripherals are described....

  7. Catalysts under Controlled Atmospheres in the Transmission Electron Microscope

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; Wagner, Jakob Birkedal

    2014-01-01

    of resolution. Using suitably clean gases, modified pumping schemes, and short pathways through dense gas regions, these issues are now circumvented. Here we provide an account of best practice using environmental transmission electron microscopy on catalytic systems illustrated using select examples from......Over time, there has been an increasing interest in observing catalysts in their operating environment at high spatial resolution and ultimately to determine the structure of a catalytically active surface. One tool with the potential to do exactly this in direct space is the transmission electron...

  8. New light on the Kr-(4p55s2) Feshbach resonances: high-resolution electron scattering experiments and B-spline R-matrix calculations

    International Nuclear Information System (INIS)

    Hoffmann, T H; Ruf, M-W; Hotop, H; Zatsarinny, O; Bartschat, K; Allan, M

    2010-01-01

    In a joint experimental and theoretical effort, we carried out a detailed study of electron scattering from Kr atoms in the energy range of the low-lying Kr - (4p 5 5s 2 ) Feshbach resonances. Absolute angle-differential cross sections for elastic electron scattering were measured over the energy range 9.3-10.3 eV with an energy width of about 13 meV at scattering angles between 10 deg. and 180 deg. Using several sets of elastic scattering phase shifts, a detailed analysis of the sharp Kr - (4p 5 5s 2 2 P 3/2 ) resonance was carried out, resulting in a resonance width of Γ 3/2 3.6(2) meV. By direct comparison with the position of the Ar - (3p 5 4s 2 2 P 3/2 ) resonance, the energy for the Kr - (4p 5 5s 2 2 P 3/2 ) resonance was determined as E 3/2 = 9.489(3) eV. A Fano-type fit of the higher lying Kr - (4p 5 5s 2 2 P 1/2 ) resonance yielded the resonance parameters Γ 1/2 = 33(5) meV and E 1/2 = 10.126(4) eV. In order to obtain additional insights, B-spline R-matrix calculations were performed for both the elastic and the inelastic cross sections above the threshold for 4p 5 5s excitation. They provide the total and angle-differential cross sections for excitation of long-lived and short-lived levels of the 4p 5 5s configuration in Kr and branching ratios for the decay of the Kr - (4p 5 5s 2 2 P 1/2 ) resonance into the three available exit channels. The results are compared with selected experimental data.

  9. High-resolution studies of tropolone in the S0 and S1 electronic states: isotope driven dynamics in the zero-point energy levels.

    Science.gov (United States)

    Keske, John C; Lin, Wei; Pringle, Wallace C; Novick, Stewart E; Blake, Thomas A; Plusquellic, David F

    2006-02-21

    Rotationally resolved microwave (MW) and ultraviolet (UV) spectra of jet-cooled tropolone have been obtained in S(0) and S(1) electronic states using Fourier-transform microwave and UV-laser/molecular-beam spectrometers. In the ground electronic state, the MW spectra of all heavy-atom isotopomers including one (18)O and four (13)C isotopomers were observed in natural abundance. The OD isotopomer was obtained from isotopically enriched samples. The two lowest tunneling states of each isotopomer except (18)O have been assigned. The observed inversion splitting for the OD isotopomer is 1523.227(5) MHz. For the asymmetric (13)C structures, the magnitudes of tunneling-rotation interactions are found to diminish with decreasing distance between the heavy atom and the tunneling proton. In the limit of closest approach, the 0(+) state of (18)O was well fitted to an asymmetric rotor Hamiltonian, reflecting significant changes in the tautomerization dynamics. Comparisons of the substituted atom coordinates with theoretical predictions at the MP2/aug-cc-pVTZ level of theory suggest the localized 0(+) and 0(-) wave functions of the heavier isotopes favor the C-OH and C=O forms of tropolone, respectively. The only exception occurs for the (13)C-OH and (13)C[Double Bond]O structures which correlate to the 0(-) and 0(+) states, respectively. These preferences reflect kinetic isotope effects as quantitatively verified by the calculated zero-point energy differences between members of the asymmetric atom pairs. From rotationally resolved data of the 0(+) <--0(+) and 0(-) <--0(-) bands in S(1), line-shape fits have yielded Lorentzian linewidths that differ by 12.2(16) MHz over the 19.88(4) cm(-1) interval in S(1). The fluorescence decay rates together with previously reported quantum yield data give nonradiative decay rates of 7.7(5) x 10(8) and 8.5(5) x 10(8) s(-1) for the 0(+) and 0(-) levels of the S(1) state of tropolone.

  10. Novel low-dose imaging technique for characterizing atomic structures through scanning transmission electron microscope

    Science.gov (United States)

    Su, Chia-Ping; Syu, Wei-Jhe; Hsiao, Chien-Nan; Lai, Ping-Shan; Chen, Chien-Chun

    2017-08-01

    To investigate dislocations or heterostructures across interfaces is now of great interest to condensed matter and materials scientists. With the advances in aberration-corrected electron optics, the scanning transmission electron microscope has demonstrated its excellent capability of characterizing atomic structures within nanomaterials, and well-resolved atomic-resolution images can be obtained through long-exposure data acquisition. However, the sample drifting, carbon contamination, and radiation damage hinder further analysis, such as deriving three-dimensional (3D) structures from a series of images. In this study, a method for obtaining atomic-resolution images with significantly reduced exposure time was developed, using which an original high-resolution image with approximately one tenth the electron dose can be obtained by combining a fast-scan high-magnification image and a slow-scan low-magnification image. The feasibility of obtaining 3D atomic structures using the proposed approach was demonstrated through multislice simulation. Finally, the feasibility and accuracy of image restoration were experimentally verified. This general method cannot only apply to electron microscopy but also benefit to image radiation-sensitive materials using various light sources.

  11. A high-resolution detector based on liquid-core scintillating fibres with readout via an electron-bombarded charge-coupled device

    International Nuclear Information System (INIS)

    Cianfarani, C.; Duane, A.; Fabre, J.P.; Frenkel, A.; Golovkin, S.V.; Gorin, A.M.; Harrison, K.; Kozarenko, E.N.; Kushnirenko, A.E.; Ladygin, E.A.; Martellotti, G.; Medvedkov, A.M.; Nass, P.A.; Obudovski, V.P.; Penso, G.; Petukhov, Yu.P.; Siegmund, W.P.; Tyukov, V.E.; Vasilchenko, V.G.

    1994-01-01

    This paper is a presentation of results from tests in a 5 GeV/c hadron beam of detectors based on liquid-core scintillating fibres, each fibre consisting of a glass capillary filled with organic liquid scintillator. Fibre readout was performed via an Electron-Bombarded Charge-Coupled Device (EBCCD) image tube, a novel instrument that combines the functions of a high-gain, gated image intensifier and a Charge-Coupled Device. Using 1-methylnaphthalene doped with 3 g/l of R45 as liquid scintillator, the attenuation lengths obtained for light propagation over distances greater than 16 cm were 1.5 m in fibres of 20 μm core and 1.0 m in fibres of 16 μm core. For particles that crossed the fibres of 20 μm core at distances of ∼1.8 cm and ∼95 cm from the fibres' readout ends, the recorded hit densities were 5.3 mm -1 and 2.5 mm -1 respectively. Using 1-methylnaphthalene doped with 3.6 g/l of R39 as liquid scintillator and fibres of 75 μm core, the hit density obtained for particles that crossed the fibres at a distance of ∼1.8 cm from their readout ends was 8.5 mm -1 . With a specially designed bundle of tapered fibres, having core diameters that smoothly increase from 16 μm to 75 μm, a spatial precision of 6 μm was measured. (orig.)

  12. Study of electric monopole transitions between the ground state and the first excited O+-state in 40,42,44,48Ca with high resolution inelastic electron scattering

    International Nuclear Information System (INIS)

    Strottman, D.; Graef, H.D.; Feldmeier, H.; Manakos, P.; Richter, A.; Spamer, E.

    1977-11-01

    Monopole transitions from the O + 1 ground states to O + 2 excited states at 3.353 MeV ( 40 Ca), 1.837 MeV ( 42 Ca), 1.884 MeV ( 44 Ca) and 4.272 Mev ( 48 Ca) have been investigated with high resolution inelastic electron scattering (FWHM approximately equal to 30 keV) at low momentum transfer (0.29 fm -1 -1 ). The respective monopole matrix elements are (2.53 +- 0.41) fm 2 , (5.24 +- 0.39) fm 2 , (5.45 +- 0.41) fm 2 and (2.28 +- 0.49) fm 2 . These results are used together with known ground state charge radii and the average number of holes in the sd-shell in the ground state to estimate the number of particle-hole excitations in the wavefunctions of th excited O + states. (orig.) [de

  13. Study of the niobium dehydrogenation process by transmission electron microscopy

    International Nuclear Information System (INIS)

    Bulhoes, I.A.M.; Akune, K.

    1983-01-01

    The evolution of the micro-structure of Nb-H, during the dehydrogenation process through thermal treatment, has been studied by Transmission Electron Microscopy. The results are used in order to interpret the variation of the line resolution of Electron Channeling Pattern (ECP) of Nb-H as a function of isochronous annealing temperature. It is concluded that the improvement of the ECP line resolution is enhanced of β hydrate in Nb. (Author) [pt

  14. High-resolution X-ray television and high-resolution video recorders

    International Nuclear Information System (INIS)

    Haendle, J.; Horbaschek, H.; Alexandrescu, M.

    1977-01-01

    The improved transmission properties of the high-resolution X-ray television chain described here make it possible to transmit more information per television image. The resolution in the fluoroscopic image, which is visually determined, depends on the dose rate and the inertia of the television pick-up tube. This connection is discussed. In the last few years, video recorders have been increasingly used in X-ray diagnostics. The video recorder is a further quality-limiting element in X-ray television. The development of function patterns of high-resolution magnetic video recorders shows that this quality drop may be largely overcome. The influence of electrical band width and number of lines on the resolution in the X-ray television image stored is explained in more detail. (orig.) [de

  15. Three-Dimensional Orientation Mapping in the Transmission Electron Microscope

    DEFF Research Database (Denmark)

    Liu, Haihua; Schmidt, Søren; Poulsen, Henning Friis

    2011-01-01

    resolution of 200 nanometers (nm). We describe here a nondestructive technique that enables 3D orientation mapping in the transmission electron microscope of mono- and multiphase nanocrystalline materials with a spatial resolution reaching 1 nm. We demonstrate the technique by an experimental study...

  16. Ion source for thinning of specimen in transmission electron microscopy

    International Nuclear Information System (INIS)

    Hammer, K.; Rothe, R.

    1983-01-01

    Thinning of specimen for transmission electron microscopy is carried out by means of sputtering. Construction, design, and operation parameters of an ion source are presented. Because the plasma is produced by means of hollow cathode glow discharges, no special focusing system is used

  17. Highlighting material structure with transmission electron diffraction correlation coefficient maps.

    Science.gov (United States)

    Kiss, Ákos K; Rauch, Edgar F; Lábár, János L

    2016-04-01

    Correlation coefficient maps are constructed by computing the differences between neighboring diffraction patterns collected in a transmission electron microscope in scanning mode. The maps are shown to highlight material structural features like grain boundaries, second phase particles or dislocations. The inclination of the inner crystal interfaces are directly deduced from the resulting contrast. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. In situ Electrical measurements in Transmission Electron Microscopy

    NARCIS (Netherlands)

    Rudneva, M.

    2013-01-01

    In the present thesis the combination of real-time electricalmeasurements on nano-sampleswith simultaneous examination by transmission electron microscope (TEM) is discussed. Application of an electrical current may lead to changes in the samples thus the possibility to correlate such changes with

  19. Diffuse x-ray scattering and transmission electron microscopy study of defects in antimony-implanted silicon

    Science.gov (United States)

    Takamura, Y.; Marshall, A. F.; Mehta, A.; Arthur, J.; Griffin, P. B.; Plummer, J. D.; Patel, J. R.

    2004-04-01

    Ion implantation followed by laser annealing has been used to create supersaturated and electrically active concentrations of antimony in silicon. Upon subsequent thermal annealing, however, these metastable dopants deactivate towards the equilibrium solubility limit. In this work, the formation of inactive antimony structures has been studied with grazing incidence diffuse x-ray scattering, and transmission electron microscopy, and the results are correlated to previous high-resolution x-ray diffraction data. We find that at a concentration of 6.0×1020 cm-3, small, incoherent clusters of radius 3-4 Å form during annealing at 900 °C. At a higher concentration of 2.2×1021 cm-3, deactivation at 600 °C occurs through the formation of small, antimony aggregates and antimony precipitates. The size of these precipitates from diffuse x-ray scattering is roughly 15 Å in radius for anneal times from 15 to 180 seconds. This value is consistent with the features observed in high-resolution and mass contrast transmission electron microscopy images. The coherent nature of the aggregates and precipitates causes the expansion of the surrounding silicon matrix as the deactivation progresses. In addition, the sensitivity of the diffuse x-ray scattering technique has allowed us to detect the presence of small clusters of radius ˜2 Å in unprocessed Czochralski silicon wafers. These defects are not observed in floating zone silicon wafers, and are tentatively attributed to thermal donors.

  20. Foucault imaging by using non-dedicated transmission electron microscope

    International Nuclear Information System (INIS)

    Taniguchi, Yoshifumi; Matsumoto, Hiroaki; Harada, Ken

    2012-01-01

    An electron optical system for observing Foucault images was constructed using a conventional transmission electron microscope without any special equipment for Lorentz microscopy. The objective lens was switched off and an electron beam was converged by a condenser optical system to the crossover on the selected area aperture plane. The selected area aperture was used as an objective aperture to select the deflected beam for Foucault mode, and the successive image-forming lenses were controlled for observation of the specimen images. The irradiation area on the specimen was controlled by selecting the appropriate diameter of the condenser aperture.

  1. Foucault imaging by using non-dedicated transmission electron microscope

    Science.gov (United States)

    Taniguchi, Yoshifumi; Matsumoto, Hiroaki; Harada, Ken

    2012-08-01

    An electron optical system for observing Foucault images was constructed using a conventional transmission electron microscope without any special equipment for Lorentz microscopy. The objective lens was switched off and an electron beam was converged by a condenser optical system to the crossover on the selected area aperture plane. The selected area aperture was used as an objective aperture to select the deflected beam for Foucault mode, and the successive image-forming lenses were controlled for observation of the specimen images. The irradiation area on the specimen was controlled by selecting the appropriate diameter of the condenser aperture.

  2. Foucault imaging by using non-dedicated transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Taniguchi, Yoshifumi [Science and Medical Systems Business Group, Hitachi High-Technologies Corp., Ichige, Hitachinaka, Ibaraki 312-8504 (Japan); Matsumoto, Hiroaki [Corporate Manufacturing Strategy Group, Hitachi High-Technologies Corp., Ishikawa-cho, Hitachinaka, Ibaraki 312-1991 (Japan); Harada, Ken [Central Research Laboratory, Hitachi Ltd., Hatoyama, Saitama 350-0395 (Japan)

    2012-08-27

    An electron optical system for observing Foucault images was constructed using a conventional transmission electron microscope without any special equipment for Lorentz microscopy. The objective lens was switched off and an electron beam was converged by a condenser optical system to the crossover on the selected area aperture plane. The selected area aperture was used as an objective aperture to select the deflected beam for Foucault mode, and the successive image-forming lenses were controlled for observation of the specimen images. The irradiation area on the specimen was controlled by selecting the appropriate diameter of the condenser aperture.

  3. Measurement of suprathermal electron confinement by cyclotron transmission

    International Nuclear Information System (INIS)

    Kirkwood, R.; Hutchinson, I.H.; Luckhardt, S.C.; Porkolab, M.; Squire, J.P.

    1990-01-01

    The confinement time of suprathermal electrons is determined experimentally from the distribution function determined via wave transmission measurements. Measurements of the lowest moment of the distribution perpendicular to the B field as a function of the parallel electron momentum as well as the global input power allow the suprathermal electron confinement time (τ se ) to be calculated during lower-hybrid and inductive current drive. Finite particle confinement is found to be the dominant energy loss term for the suprathermals and improves with plasma current and density

  4. Transmission environmental scanning electron microscope with scintillation gaseous detection device.

    Science.gov (United States)

    Danilatos, Gerasimos; Kollia, Mary; Dracopoulos, Vassileios

    2015-03-01

    A transmission environmental scanning electron microscope with use of a scintillation gaseous detection device has been implemented. This corresponds to a transmission scanning electron microscope but with addition of a gaseous environment acting both as environmental and detection medium. A commercial type of low vacuum machine has been employed together with appropriate modifications to the detection configuration. This involves controlled screening of various emitted signals in conjunction with a scintillation gaseous detection device already provided with the machine for regular surface imaging. Dark field and bright field imaging has been obtained along with other detection conditions. With a progressive series of modifications and tests, the theory and practice of a novel type of microscopy is briefly shown now ushering further significant improvements and developments in electron microscopy as a whole. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. An accurate test of calculated positions and lifetimes for Ne{sup 6+}(1s{sup 2}3lnl{sup '}) {sup 1}L states (n=3 and 4) using a high-resolution electron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, A. E-mail: abm@irsamc.ups-tlse.fr; Moretto-Capelle, P.; Bordenave-Montesquieu, D

    2003-05-01

    An accurate test of available calculations for the autoionizing doubly excited states belonging to the Be-like 1s{sup 2}3lnl{sup '} Rydberg series of neon (positions and lifetimes) is presented in this short communication. These theoretical data are used to calculate electron line shapes which are compared, through a fitting procedure, with a high-resolution electron spectrum measured in Ne{sup 8+}(1s{sup 2}) + He collisional system, at 80 keV collision energy and 13.1 deg. observation angle. Present tests concern the n=3 and n=4 singlet states. It is found that some of these calculations suffer from large discrepancies with experiment and do not allow a description of the electron spectrum. A quantitative comparison of measured and calculated post-collisional Coulomb interaction-shifted line positions is also given and briefly discussed; for one theoretical data set, the agreement with experiment is found to be generally within {+-}50 meV; in contrast agreement with other data often considerably scatters within {+-}500 meV and sometimes more.

  6. An accurate test of calculated positions and lifetimes for Ne6+(1s23lnl') 1L states (n=3 and 4) using a high-resolution electron spectroscopy

    International Nuclear Information System (INIS)

    Bordenave-Montesquieu, A.; Moretto-Capelle, P.; Bordenave-Montesquieu, D.

    2003-01-01

    An accurate test of available calculations for the autoionizing doubly excited states belonging to the Be-like 1s 2 3lnl ' Rydberg series of neon (positions and lifetimes) is presented in this short communication. These theoretical data are used to calculate electron line shapes which are compared, through a fitting procedure, with a high-resolution electron spectrum measured in Ne 8+ (1s 2 ) + He collisional system, at 80 keV collision energy and 13.1 deg. observation angle. Present tests concern the n=3 and n=4 singlet states. It is found that some of these calculations suffer from large discrepancies with experiment and do not allow a description of the electron spectrum. A quantitative comparison of measured and calculated post-collisional Coulomb interaction-shifted line positions is also given and briefly discussed; for one theoretical data set, the agreement with experiment is found to be generally within ±50 meV; in contrast agreement with other data often considerably scatters within ±500 meV and sometimes more

  7. Electronic Biometric Transmission Specification. Version 1.2

    Science.gov (United States)

    2006-11-08

    Prescribed by ANSI Std Z39-18 Electronic Biometric Transmission Specification DIN: DOD_BTF_TS_EBTS_ Nov06_01.02.00 i Revision History Revision...contains: • the ORI • a Greenwich Mean (a.k.a. Zulu or UTC) date/time stamp • a code for the software used at the point of collection/transmission...long names and would generally include the tribe name. Subfield 1 Item 1 Character Type AS Characters 1 to 50 Special Characters: Any 7-bit non

  8. High-resolution ultrasonic spectroscopy

    Directory of Open Access Journals (Sweden)

    V. Buckin

    2018-03-01

    Full Text Available High-resolution ultrasonic spectroscopy (HR-US is an analytical technique for direct and non-destructive monitoring of molecular and micro-structural transformations in liquids and semi-solid materials. It is based on precision measurements of ultrasonic velocity and attenuation in analysed samples. The application areas of HR-US in research, product development, and quality and process control include analysis of conformational transitions of polymers, ligand binding, molecular self-assembly and aggregation, crystallisation, gelation, characterisation of phase transitions and phase diagrams, and monitoring of chemical and biochemical reactions. The technique does not require optical markers or optical transparency. The HR-US measurements can be performed in small sample volumes (down to droplet size, over broad temperature range, at ambient and elevated pressures, and in various measuring regimes such as automatic temperature ramps, titrations and measurements in flow.

  9. High Resolution Thermometry for EXACT

    Science.gov (United States)

    Panek, J. S.; Nash, A. E.; Larson, M.; Mulders, N.

    2000-01-01

    High Resolution Thermometers (HRTs) based on SQUID detection of the magnetization of a paramagnetic salt or a metal alloy has been commonly used for sub-nano Kelvin temperature resolution in low temperature physics experiments. The main applications to date have been for temperature ranges near the lambda point of He-4 (2.177 K). These thermometers made use of materials such as Cu(NH4)2Br4 *2H2O, GdCl3, or PdFe. None of these materials are suitable for EXACT, which will explore the region of the He-3/He-4 tricritical point at 0.87 K. The experiment requirements and properties of several candidate paramagnetic materials will be presented, as well as preliminary test results.

  10. High resolution tomographic instrument development

    International Nuclear Information System (INIS)

    1992-01-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational

  11. High resolution tomographic instrument development

    Energy Technology Data Exchange (ETDEWEB)

    1992-08-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  12. High resolution tomographic instrument development

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    Our recent work has concentrated on the development of high-resolution PET instrumentation reflecting in part the growing importance of PET in nuclear medicine imaging. We have developed a number of positron imaging instruments and have the distinction that every instrument has been placed in operation and has had an extensive history of application for basic research and clinical study. The present program is a logical continuation of these earlier successes. PCR-I, a single ring positron tomograph was the first demonstration of analog coding using BGO. It employed 4 mm detectors and is currently being used for a wide range of biological studies. These are of immense importance in guiding the direction for future instruments. In particular, PCR-II, a volume sensitive positron tomograph with 3 mm spatial resolution has benefited greatly from the studies using PCR-I. PCR-II is currently in the final stages of assembly and testing and will shortly be placed in operation for imaging phantoms, animals and ultimately humans. Perhaps the most important finding resulting from our previous study is that resolution and sensitivity must be carefully balanced to achieve a practical high resolution system. PCR-II has been designed to have the detection characteristics required to achieve 3 mm resolution in human brain under practical imaging situations. The development of algorithms by the group headed by Dr. Chesler is based on a long history of prior study including his joint work with Drs. Pelc and Reiderer and Stearns. This body of expertise will be applied to the processing of data from PCR-II when it becomes operational.

  13. High-resolution neutron and X-ray diffraction room-temperature studies of an H-FABP–oleic acid complex: study of the internal water cluster and ligand binding by a transferred multipolar electron-density distribution

    Directory of Open Access Journals (Sweden)

    E. I. Howard

    2016-03-01

    Full Text Available Crystal diffraction data of heart fatty acid binding protein (H-FABP in complex with oleic acid were measured at room temperature with high-resolution X-ray and neutron protein crystallography (0.98 and 1.90 Å resolution, respectively. These data provided very detailed information about the cluster of water molecules and the bound oleic acid in the H-FABP large internal cavity. The jointly refined X-ray/neutron structure of H-FABP was complemented by a transferred multipolar electron-density distribution using the parameters of the ELMAMII library. The resulting electron density allowed a precise determination of the electrostatic potential in the fatty acid (FA binding pocket. Bader's quantum theory of atoms in molecules was then used to study interactions involving the internal water molecules, the FA and the protein. This approach showed H...H contacts of the FA with highly conserved hydrophobic residues known to play a role in the stabilization of long-chain FAs in the binding cavity. The determination of water hydrogen (deuterium positions allowed the analysis of the orientation and electrostatic properties of the water molecules in the very ordered cluster. As a result, a significant alignment of the permanent dipoles of the water molecules with the protein electrostatic field was observed. This can be related to the dielectric properties of hydration layers around proteins, where the shielding of electrostatic interactions depends directly on the rotational degrees of freedom of the water molecules in the interface.

  14. High resolution techniques using scanning proton microprobe (SPM)

    International Nuclear Information System (INIS)

    Cholewa, M.; Saint, A.; Prawer, S.; Laird, J.S.; Legge, G.J.F.; Bardos, R.A.; Moorhead, G.F.; Taylor, G.N.; Stuart, S.A.; Howard, J.

    1994-01-01

    The very high resolution (down to 50 nm) achieved with low beam currents (fA) in a scanning ion microprobe have lead to many nondestructive techniques of microanalysis. This paper discusses recent developments and applications in the use of 3-D STIM (scanning transmission ion microscopy) Tomography, channeling STIM and IBIC (ion beam induced charge). (orig.)

  15. Depth profiling: RBS versus energy-dispersive X-ray imaging using scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Markwitz, Andreas

    2000-01-01

    Rutherford backscattering spectrometry (RBS) is known to be one of the techniques ideal for analysis of thin films. Elemental concentrations of matrix components and impurities can be investigated as well as depth profiles of almost each element of the periodic table. Best of all, RBS has both a high sensitivity and a high depth resolution, and is a non-destructive analysis technique that does not require specific sample preparation. Solid-state samples are mounted without preparation inside a high-vacuum analysis chamber. However, depth-related interpretation of elemental depth profiles requires the material density of the specimen and stopping power values to be taken into consideration. In many cases, these parameters can be estimated with sufficient precision. However, the assumed density can be inaccurate for depth scales in the nanometer range. For example, in the case of Ge nanoclusters in 500 nm thick SiO 2 layers, uncertainty is related to the actual position of a very thin Ge nanocluster band. Energy-dispersive X-ray emission (EDX) spectroscopy, using a high-resolution scanning transmission electron microscope (STEM) can assist in removing this uncertainty. By preparing a thin section of the specimen, EDX can be used to identify the position of the Ge nanocluster band very precisely, by correlating the Ge profile with the depth profiles of silicon and oxygen. However, extraction of the concentration profiles from STEM-EDX spectra is in general not straightforward. Therefore, a combination of the two very different analysis techniques is often the best and only successful way to extract high-resolution concentration profiles

  16. Electron transmission through a periodically driven graphene magnetic barrier

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, R., E-mail: rbiswas.pkc@gmail.com [Department of Physics, P. K. College, Contai, Purba Medinipur, West Bengal – 721401 (India); Maiti, S. [Ajodhya Hills G.S.A.T High School, Ajodhya, Purulia, West Bengal – 723152 (India); Mukhopadhyay, S. [Purulia Zilla School, Dulmi Nadiha, Purulia, West Bengal – 723102 (India); Sinha, C. [Department of Physics, P. K. College, Contai, Purba Medinipur, West Bengal – 721401 (India); Department of Theoretical Physics, Indian Association for the Cultivation of Science, Jadavpur – 700032 (India)

    2017-05-10

    Electronic transport through graphene magnetic barriers is studied theoretically in presence of an external time harmonic scalar potential in the framework of non-perturbative Landau–Floquet Formalism. The oscillating field mostly suppresses the transmission for rectangular magnetic barrier structure and exhibits the Fano resonance for multiphoton processes due to the presence of bound state inside the barrier. While, for a pair of delta function barriers of larger separation, the oscillating potential suppresses the usual Fabry–Perot oscillations in the transmission and a new type of asymmetric Fano resonance is noted for smaller separation, occurring due to extended states between the barriers. - Highlights: • Tunnelling of the Dirac Fermions through oscillating pure magnetic barriers is reported for the first time. • The high energy transmission through a graphene magnetic barrier is suppressed by the application of time periodic modulation. • Suppression of the Fabry Perot transmission is noted due to the application of an external time harmonic potential. • Two kinds of the Fano resonances are noted in transmission through a pair of modulated δ-function magnetic barriers.

  17. Transmission of high-power electron beams through small apertures

    International Nuclear Information System (INIS)

    Tschalär, C.; Alarcon, R.; Balascuta, S.; Benson, S.V.; Bertozzi, W.; Boyce, J.R.; Cowan, R.; Douglas, D.; Evtushenko, P.; Fisher, P.; Ihloff, E.; Kalantarians, N.; Kelleher, A.; Legg, R.; Milner, R.G.; Neil, G.R.; Ou, L.; Schmookler, B.; Tennant, C.; Williams, G.P.

    2013-01-01

    Tests were performed to pass a 100 MeV, 430 kWatt c.w. electron beam from the energy-recovery linac at the Jefferson Laboratory's FEL facility through a set of small apertures in a 127 mm long aluminum block. Beam transmission losses of 3 p.p.m. through a 2 mm diameter aperture were maintained during a 7 h continuous run

  18. Cross-sectional transmission electron microscopy of semiconductors

    International Nuclear Information System (INIS)

    Sadana, D.K.

    1982-10-01

    A method to prepare cross-sectional (X) semiconductor specimens for transmission electron microscopy (TEM) has been described. The power and utility of XTEM has been demonstrated. It has been shown that accuracy and interpretation of indirect structural-defects profiling techniques, namely, MeV He + channeling and secondary ion mass spectrometry (SIMS) can be greatly enhanced by comparing their results with those obtained by XTEM from the same set of samples

  19. Reciprocity relations in transmission electron microscopy: A rigorous derivation.

    Science.gov (United States)

    Krause, Florian F; Rosenauer, Andreas

    2017-01-01

    A concise derivation of the principle of reciprocity applied to realistic transmission electron microscopy setups is presented making use of the multislice formalism. The equivalence of images acquired in conventional and scanning mode is thereby rigorously shown. The conditions for the applicability of the found reciprocity relations is discussed. Furthermore the positions of apertures in relation to the corresponding lenses are considered, a subject which scarcely has been addressed in previous publications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Multistage linear electron acceleration using pulsed transmission lines

    International Nuclear Information System (INIS)

    Miller, R.B.; Prestwich, K.R.; Poukey, J.W.; Epstein, B.G.; Freeman, J.R.; Sharpe, A.W.; Tucker, W.K.; Shope, S.L.

    1981-01-01

    A four-stage linear electron accelerator is described which uses pulsed radial transmission lines as the basic accelerating units. An annular electron beam produced by a foilless diode is guided through the accelerator by a strong axial magnetic field. Synchronous firing of the injector and the acccelerating modules is accomplished with self-breaking oil switches. The device has accelerated beam currents of 25 kA to kinetic energies of 9 MV, with 90% current transport efficiency. The average accelerating gradient is 3 MV/m

  1. Pulsed Power for a Dynamic Transmission Electron Microscope

    Energy Technology Data Exchange (ETDEWEB)

    dehope, w j; browning, n; campbell, g; cook, e; king, w; lagrange, t; reed, b; stuart, b; Shuttlesworth, R; Pyke, B

    2009-06-25

    Lawrence Livermore National Laboratory (LLNL) has converted a commercial 200kV transmission electron microscope (TEM) into an ultrafast, nanoscale diagnostic tool for material science studies. The resulting Dynamic Transmission Electron Microscope (DTEM) has provided a unique tool for the study of material phase transitions, reaction front analyses, and other studies in the fields of chemistry, materials science, and biology. The TEM's thermionic electron emission source was replaced with a fast photocathode and a laser beam path was provided for ultraviolet surface illumination. The resulting photoelectron beam gives downstream images of 2 and 20 ns exposure times at 100 and 10 nm spatial resolution. A separate laser, used as a pump pulse, is used to heat, ignite, or shock samples while the photocathode electron pulses, carefully time-synchronized with the pump, function as probe in fast transient studies. The device functions in both imaging and diffraction modes. A laser upgrade is underway to make arbitrary cathode pulse trains of variable pulse width of 10-1000 ns. Along with a fast e-beam deflection scheme, a 'movie mode' capability will be added to this unique diagnostic tool. This talk will review conventional electron microscopy and its limitations, discuss the development and capabilities of DTEM, in particularly addressing the prime and pulsed power considerations in the design and fabrication of the DTEM, and conclude with the presentation of a deflector and solid-state pulser design for Movie-Mode DTEM.

  2. Pulsed Power for a Dynamic Transmission Electron Microscope

    International Nuclear Information System (INIS)

    DeHope, W.J.; Browning, N.; Campbell, G.; Cook, E.; King, W.; Lagrange, T.; Reed, B.; Stuart, B.; Shuttlesworth, R.; Pyke, B.

    2009-01-01

    Lawrence Livermore National Laboratory (LLNL) has converted a commercial 200kV transmission electron microscope (TEM) into an ultrafast, nanoscale diagnostic tool for material science studies. The resulting Dynamic Transmission Electron Microscope (DTEM) has provided a unique tool for the study of material phase transitions, reaction front analyses, and other studies in the fields of chemistry, materials science, and biology. The TEM's thermionic electron emission source was replaced with a fast photocathode and a laser beam path was provided for ultraviolet surface illumination. The resulting photoelectron beam gives downstream images of 2 and 20 ns exposure times at 100 and 10 nm spatial resolution. A separate laser, used as a pump pulse, is used to heat, ignite, or shock samples while the photocathode electron pulses, carefully time-synchronized with the pump, function as probe in fast transient studies. The device functions in both imaging and diffraction modes. A laser upgrade is underway to make arbitrary cathode pulse trains of variable pulse width of 10-1000 ns. Along with a fast e-beam deflection scheme, a 'movie mode' capability will be added to this unique diagnostic tool. This talk will review conventional electron microscopy and its limitations, discuss the development and capabilities of DTEM, in particularly addressing the prime and pulsed power considerations in the design and fabrication of the DTEM, and conclude with the presentation of a deflector and solid-state pulser design for Movie-Mode DTEM

  3. High resolution studies of barium Rydberg states

    International Nuclear Information System (INIS)

    Eliel, E.R.

    1982-01-01

    The subtle structure of Rydberg states of barium with orbital angular momentum 0, 1, 2 and 3 is investigated. Some aspects of atomic theory for a configuration with two valence electrons are reviewed. The Multi Channel Quantum Defect Theory (MQDT) is concisely introduced as a convenient way to describe interactions between Rydberg series. Three high-resolution UV studies are presented. The first two, presenting results on a transition in indium and europium serve as an illustration of the frequency doubling technique. The third study is of hyperfine structure and isotope shifts in low-lying p states in Sr and Ba. An extensive study of the 6snp and 6snf Rydberg states of barium is presented with particular emphasis on the 6snf states. It is shown that the level structure cannot be fully explained with the model introduced earlier. Rather an effective two-body spin-orbit interaction has to be introduced to account for the observed splittings, illustrating that high resolution studies on Rydberg states offer an unique opportunity to determine the importance of such effects. Finally, the 6sns and 6snd series are considered. The hyperfine induced isotope shift in the simple excitation spectra to 6sns 1 S 0 is discussed and attention is paid to series perturbers. It is shown that level mixing parameters can easily be extracted from the experimental data. (Auth.)

  4. A Simple Transmission Electron Microscopy Method for Fast Thickness Characterization of Suspended Graphene and Graphite Flakes.

    Science.gov (United States)

    Rubino, Stefano; Akhtar, Sultan; Leifer, Klaus

    2016-02-01

    We present a simple, fast method for thickness characterization of suspended graphene/graphite flakes that is based on transmission electron microscopy (TEM). We derive an analytical expression for the intensity of the transmitted electron beam I 0(t), as a function of the specimen thickness t (tgraphite). We show that in thin graphite crystals the transmitted intensity is a linear function of t. Furthermore, high-resolution (HR) TEM simulations are performed to obtain λ for a 001 zone axis orientation, in a two-beam case and in a low symmetry orientation. Subsequently, HR (used to determine t) and bright-field (to measure I 0(0) and I 0(t)) images were acquired to experimentally determine λ. The experimental value measured in low symmetry orientation matches the calculated value (i.e., λ=225±9 nm). The simulations also show that the linear approximation is valid up to a sample thickness of 3-4 nm regardless of the orientation and up to several ten nanometers for a low symmetry orientation. When compared with standard techniques for thickness determination of graphene/graphite, the method we propose has the advantage of being simple and fast, requiring only the acquisition of bright-field images.

  5. High-resolution electron spectroscopy of the 1s{sup 2}3lnl' Be-like series in oxygen and neon. Test of theoretical data: II. Experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, A; Moretto-Capelle, P; Bordenave-Montesquieu, D [Laboratoire CAR-IRSAMC, UMR 5589 CNRS - Universite Paul Sabatier, 31062 Toulouse (France)

    2003-01-14

    A complete and accurate experimental test of theoretical spectroscopic data sets (state positions, lifetimes) available for the n=3-5 terms of the 1s{sup 2}3lnl' Rydberg series of oxygen and neon ions is presented in a series of two papers. This result was achieved by fitting our high-resolution electron spectra with post-collisional lineshapes calculated with the help of these spectroscopic data. In this second paper we apply the fitting procedure described in the preceding companion paper (I) to the analysis of high-resolution electron spectra measured in O{sup 6+} (1s{sup 2}) + He, H{sub 2} and Ne{sup 8+} (1s{sup 2}) + He collisional systems at 10 qkeV collision energy (q is the ion charge). Singlet states alone are found to be excited in oxygen; they also explain most of the neon lines; in the latter case a possible contribution of triplet states is discussed. Many 1s{sup 2}3lnl' {sup 1}L transitions are identified for the first time. A quantitative comparison between measured and calculated positions clearly points to the best theoretical data currently available. Finally, a first identification of some 4l4l' {sup 1}L transitions observed in the neon spectrum is also proposed. From this huge spectroscopic work, we extract the first experimental partial branching ratios for autoionization into the 1s{sup 2}2l ionization continua for a large number of 1s{sup 2}3lnl' {sup 1}L states, which are compared with the total ones calculated by other authors; we deduce that populations of |M{sub L} vertical bar = 0 and 1 magnetic sublevels are nearly identical. The double-capture process is also briefly characterized by comparing relative populations of many n=3-5 states; it is found that the same states are populated in O{sup 6+} +H{sub 2} and Ne{sup 8+} +He collisional systems with the same relative populations.

  6. Probing the electronic structure and Au—C chemical bonding in AuCn− and AuCnH− (n = 2, 4, and 6) using high-resolution photoelectron spectroscopy

    International Nuclear Information System (INIS)

    León, Iker; Ruipérez, Fernando; Ugalde, Jesus M.; Wang, Lai-Sheng

    2016-01-01

    We report a joint photoelectron spectroscopy and theoretical study on AuC 4 − , AuC 6 − , and AuC n H − (n = 2, 4, and 6) using high-resolution photoelectron imaging and ab initio calculations. The ground state of AuC 2 H − , AuC 4 H − , and AuC 6 H − is found to be linear, while that of AuC 4 − and AuC 6 − is bent. All the species are found to be linear in their neutral ground states. The electron affinities (EAs) are measured to be 3.366(1) and 3.593(1) eV for AuC 4 and AuC 6 , respectively. Both bending and stretching frequencies are resolved in the spectra of AuC 4 − and AuC 6 − . High-resolution data of AuC n H − reveal major vibrational progressions in the Au—C stretching and bending modes. AuC 2 H − has a ground state stretching frequency of 445(10) cm −1 and a bending frequency of 260(10) cm −1 ; AuC 4 H − has a ground state stretching frequency of 340(10) cm −1 ; AuC 6 H − has a ground state stretching frequency of 260(10) cm −1 and a bending frequency of 55(10) cm −1 . The EAs are measured to be 1.475(1), 1.778(1), and 1.962(1) eV for AuC 2 H, AuC 4 H, and AuC 6 H, respectively. The strength of the Au—C bond decreases as the number of carbon atoms increases. The current study provides a wealth of electronic structure information about AuC 4 − , AuC 6 − , and AuC n H − (n = 2, 4, and 6) and their corresponding neutrals.

  7. Tailoring of electron flow current in magnetically insulated transmission lines

    Directory of Open Access Journals (Sweden)

    J. P. Martin

    2009-03-01

    Full Text Available It is desirable to optimize (minimizing both the inductance and electron flow the magnetically insulated vacuum sections of low impedance pulsed-power drivers. The goal of low inductance is understandable from basic efficiency arguments. The goal of low electron flow results from two observations: (1 flowing electrons generally do not deliver energy to (or even reach most loads, and thus constitute a loss mechanism; (2 energetic electrons deposited in a small area can cause anode damage and anode plasma formation. Low inductance and low electron flow are competing goals; an optimized system requires a balance of the two. While magnetically insulated systems are generally forgiving, there are times when optimization is crucial. For example, in large pulsed-power drivers used to energize high energy density physics loads, the electron flow as a fraction of total current is small, but that flow often reaches the anode in relatively small regions. If the anode temperature becomes high enough to desorb gas, the resulting plasma initiates a gap closure process that can impact system performance. Magnetic-pressure driven (z pinches and material equation of state loads behave like a fixed inductor for much of the drive pulse. It is clear that neither fixed gap nor constant-impedance transmission lines are optimal for driving inductive loads. This work shows a technique for developing the optimal impedance profile for the magnetically insulated section of a high-current driver. Particle-in-cell calculations are used to validate the impedance profiles developed in a radial disk magnetically insulated transmission line geometry. The input parameters are the spacing and location of the minimum gap, the effective load inductance, and the desired electron flow profile. The radial electron flow profiles from these simulations are in good agreement with theoretical predictions when driven at relatively high voltage (i.e., V≥2  MV.

  8. Photocathode Optimization for a Dynamic Transmission Electron Microscope: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, P; Flom, Z; Heinselman, K; Nguyen, T; Tung, S; Haskell, R; Reed, B W; LaGrange, T

    2011-08-04

    The Dynamic Transmission Electron Microscope (DTEM) team at Harvey Mudd College has been sponsored by LLNL to design and build a test setup for optimizing the performance of the DTEM's electron source. Unlike a traditional TEM, the DTEM achieves much faster exposure times by using photoemission from a photocathode to produce electrons for imaging. The DTEM team's work is motivated by the need to improve the coherence and current density of the electron cloud produced by the electron gun in order to increase the image resolution and contrast achievable by DTEM. The photoemission test setup is nearly complete and the team will soon complete baseline tests of electron gun performance. The photoemission laser and high voltage power supply have been repaired; the optics path for relaying the laser to the photocathode has been finalized, assembled, and aligned; the internal setup of the vacuum chamber has been finalized and mostly implemented; and system control, synchronization, and data acquisition has been implemented in LabVIEW. Immediate future work includes determining a consistent alignment procedure to place the laser waist on the photocathode, and taking baseline performance measurements of the tantalum photocathode. Future research will examine the performance of the electron gun as a function of the photoemission laser profile, the photocathode material, and the geometry and voltages of the accelerating and focusing components in the electron gun. This report presents the team's progress and outlines the work that remains.

  9. Development of a secondary electron energy analyzer for a transmission electron microscope.

    Science.gov (United States)

    Magara, Hideyuki; Tomita, Takeshi; Kondo, Yukihito; Sato, Takafumi; Akase, Zentaro; Shindo, Daisuke

    2018-04-01

    A secondary electron (SE) energy analyzer was developed for a transmission electron microscope. The analyzer comprises a microchannel plate (MCP) for detecting electrons, a coil for collecting SEs emitted from the specimen, a tube for reducing the number of backscattered electrons incident on the MCP, and a retarding mesh for selecting the energy of SEs incident on the MCP. The detection of the SEs associated with charging phenomena around a charged specimen was attempted by performing electron holography and SE spectroscopy using the energy analyzer. The results suggest that it is possible to obtain the energy spectra of SEs using the analyzer and the charging states of a specimen by electron holography simultaneously.

  10. High-Resolution Mass Spectrometers

    Science.gov (United States)

    Marshall, Alan G.; Hendrickson, Christopher L.

    2008-07-01

    Over the past decade, mass spectrometry has been revolutionized by access to instruments of increasingly high mass-resolving power. For small molecules up to ˜400 Da (e.g., drugs, metabolites, and various natural organic mixtures ranging from foods to petroleum), it is possible to determine elemental compositions (CcHhNnOoSsPp…) of thousands of chemical components simultaneously from accurate mass measurements (the same can be done up to 1000 Da if additional information is included). At higher mass, it becomes possible to identify proteins (including posttranslational modifications) from proteolytic peptides, as well as lipids, glycoconjugates, and other biological components. At even higher mass (˜100,000 Da or higher), it is possible to characterize posttranslational modifications of intact proteins and to map the binding surfaces of large biomolecule complexes. Here we review the principles and techniques of the highest-resolution analytical mass spectrometers (time-of-flight and Fourier transform ion cyclotron resonance and orbitrap mass analyzers) and describe some representative high-resolution applications.

  11. Transmission Electron Microscopy Studies of Electron-Selective Titanium Oxide Contacts in Silicon Solar Cells

    KAUST Repository

    Ali, Haider; Yang, Xinbo; Weber, Klaus; Schoenfeld, Winston V.; Davis, Kristopher O.

    2017-01-01

    In this study, the cross-section of electron-selective titanium oxide (TiO2) contacts for n-type crystalline silicon solar cells were investigated by transmission electron microscopy. It was revealed that the excellent cell efficiency of 21

  12. High resolution SETI: Experiences and prospects

    Science.gov (United States)

    Horowitz, Paul; Clubok, Ken

    Megachannel spectroscopy with sub-Hertz resolution constitutes an attractive strategy for a microwave search for extraterrestrial intelligence (SETI), assuming the transmission of a narrowband radiofrequency beacon. Such resolution matches the properties of the interstellar medium, and the necessary Doppler corrections provide a high degree of interference rejection. We have constructed a frequency-agile receiver with an FFT-based 8 megachannel digital spectrum analyzer, on-line signal recognition, and multithreshold archiving. We are using it to conduct a meridian transit search of the northern sky at the Harvard-Smithsonian 26-m antenna, with a second identical system scheduled to begin observations in Argentina this month. Successive 400 kHz spectra, at 0.05 Hz resolution, are searched for features characteristic of an intentional narrowband beacon transmission. These spectra are centered on guessable frequencies (such as λ21 cm), referenced successively to the local standard of rest, the galactic barycenter, and the cosmic blackbody rest frame. This search has rejected interference admirably, but is greatly limited both in total frequency coverage and sensitivity to signals other than carriers. We summarize five years of high resolution SETI at Harvard, in the context of answering the questions "How useful is narrowband SETI, how serious are its limitations, what can be done to circumvent them, and in what direction should SETI evolve?" Increasingly powerful signal processing hardware, combined with ever-higher memory densities, are particularly relevant, permitting the construction of compact and affordable gigachannel spectrum analyzers covering hundreds of megahertz of instantaneous bandwidth.

  13. Sample Preparation and Imaging of Exosomes by Transmission Electron Microscopy.

    Science.gov (United States)

    Jung, Min Kyo; Mun, Ji Young

    2018-01-04

    Exosomes are nano-sized extracellular vesicles secreted by body fluids and are known to represent the characteristics of cells that secrete them. The contents and morphology of the secreted vesicles reflect cell behavior or physiological status, for example cell growth, migration, cleavage, and death. The exosomes' role may depend highly on size, and the size of exosomes varies from 30 to 300 nm. The most widely used method for exosome imaging is negative staining, while other results are based on Cryo-Transmission Electron Microscopy, Scanning Electron Microscopy, and Atomic Force Microscopy. The typical exosome's morphology assessed through negative staining is a cup-shape, but further details are not yet clear. An exosome well-characterized through structural study is necessary particular in medical and pharmaceutical fields. Therefore, function-dependent morphology should be verified by electron microscopy techniques such as labeling a specific protein in the detailed structure of exosome. To observe detailed structure, ultrathin sectioned images and negative stained images of exosomes were compared. In this protocol, we suggest transmission electron microscopy for the imaging of exosomes including negative staining, whole mount immuno-staining, block preparation, thin section, and immuno-gold labelling.

  14. Using environmental transmission electron microscope to study the in-situ reduction of Co3O4 supported on α-Al2O3

    DEFF Research Database (Denmark)

    Dehghan-Niri, R.; Hansen, Thomas Willum; Wagner, Jakob Birkedal

    in specialized Transmission Electron Microscope (TEM) instruments with differentially pumped columns at pressures in the range up to 20 mbar. 1-3 The objective of this work is to study the reduction of Co3O4 nanoparticles directly and observe their morphology and crystallography. The catalysts were produced...... by dispersion of crushed powder directly on steel grids and gold grids. TEM analysis was performed with an FEI TITAN E-cell electron microscope operating at 300 kV. Reduction was done at 360°C and 3.4 mbar H2 flow. The samples were studied before and after reduction by High Resolution TEM (HRTEM) imaging, high...

  15. High resolution VUV facility at INDUS-1

    International Nuclear Information System (INIS)

    Krishnamurty, G.; Saraswathy, P.; Rao, P.M.R.; Mishra, A.P.; Kartha, V.B.

    1993-01-01

    Synchrotron radiation (SR) generated in the electron storage rings is an unique source for the study of atomic and molecular spectroscopy especially in the vacuum ultra violet region. Realizing the potential of this light source, efforts are in progress to develop a beamline facility at INDUS-1 to carry out high resolution atomic and molecular spectroscopy. This beam line consists of a fore-optic which is a combination of three cylindrical mirrors. The mirrors are so chosen that SR beam having a 60 mrad (horizontal) x 6 mrad (vertical) divergence is focussed onto a slit of a 6.65 metre off-plane spectrometer in Eagle Mount equipped with horizontal slit and vertical dispersion. The design of the various components of the beam line is completed. It is decided to build the spectrometer as per the requirements of the user community. Details of the various aspects of the beam line will be presented. (author). 3 figs

  16. In situ Transmission Electron Microscopy of catalyst sintering

    DEFF Research Database (Denmark)

    DeLaRiva, Andrew T.; Hansen, Thomas Willum; Challa, Sivakumar R.

    2013-01-01

    Recent advancements in the field of electron microscopy, such as aberration correctors, have now been integrated into Environmental Transmission Electron Microscopes (TEMs), making it possible to study the behavior of supported metal catalysts under operating conditions at atomic resolution. Here......, we focus on in situ electron microscopy studies of catalysts that shed light on the mechanistic aspects of catalyst sintering. Catalyst sintering is an important mechanism for activity loss, especially for catalysts that operate at elevated temperatures. Literature from the past decade is reviewed...... along with our recent in situ TEM studies on the sintering of Ni/MgAl2O4 catalysts. These results suggest that the rapid loss of catalyst activity in the earliest stages of catalyst sintering could result from Ostwald ripening rather than through particle migration and coalescence. The smallest...

  17. Aberration-corrected scanning transmission electron microscopy of semiconductors

    International Nuclear Information System (INIS)

    Krivanek, O L; Dellby, N; Murfitt, M F

    2011-01-01

    The scanning transmission electron microscope (STEM) has been able to image individual heavy atoms in a light matrix for some time. It is now able to do much more: it can resolve individual atoms as light as boron in monolayer materials; image atomic columns as light as hydrogen, identify the chemical type of individual isolated atoms from the intensity of their annular dark field (ADF) image and by electron energy loss spectroscopy (EELS); and map elemental composition at atomic resolution by EELS and energy-dispersive X-ray spectroscopy (EDXS). It can even map electronic states, also by EELS, at atomic resolution. The instrumentation developments that have made this level of performance possible are reviewed, and examples of applications to semiconductors and oxides are shown.

  18. Attainment of 40.5 pm spatial resolution using 300 kV scanning transmission electron microscope equipped with fifth-order aberration corrector.

    Science.gov (United States)

    Morishita, Shigeyuki; Ishikawa, Ryo; Kohno, Yuji; Sawada, Hidetaka; Shibata, Naoya; Ikuhara, Yuichi

    2018-02-01

    The achievement of a fine electron probe for high-resolution imaging in scanning transmission electron microscopy requires technological developments, especially in electron optics. For this purpose, we developed a microscope with a fifth-order aberration corrector that operates at 300 kV. The contrast flat region in an experimental Ronchigram, which indicates the aberration-free angle, was expanded to 70 mrad. By using a probe with convergence angle of 40 mrad in the scanning transmission electron microscope at 300 kV, we attained the spatial resolution of 40.5 pm, which is the projected interatomic distance between Ga-Ga atomic columns of GaN observed along [212] direction.

  19. On the Progress of Scanning Transmission Electron Microscopy (STEM) Imaging in a Scanning Electron Microscope.

    Science.gov (United States)

    Sun, Cheng; Müller, Erich; Meffert, Matthias; Gerthsen, Dagmar

    2018-04-01

    Transmission electron microscopy (TEM) with low-energy electrons has been recognized as an important addition to the family of electron microscopies as it may avoid knock-on damage and increase the contrast of weakly scattering objects. Scanning electron microscopes (SEMs) are well suited for low-energy electron microscopy with maximum electron energies of 30 keV, but they are mainly used for topography imaging of bulk samples. Implementation of a scanning transmission electron microscopy (STEM) detector and a charge-coupled-device camera for the acquisition of on-axis transmission electron diffraction (TED) patterns, in combination with recent resolution improvements, make SEMs highly interesting for structure analysis of some electron-transparent specimens which are traditionally investigated by TEM. A new aspect is correlative SEM, STEM, and TED imaging from the same specimen region in a SEM which leads to a wealth of information. Simultaneous image acquisition gives information on surface topography, inner structure including crystal defects and qualitative material contrast. Lattice-fringe resolution is obtained in bright-field STEM imaging. The benefits of correlative SEM/STEM/TED imaging in a SEM are exemplified by structure analyses from representative sample classes such as nanoparticulates and bulk materials.

  20. High resolution microstructure characterization of the interface between cold sprayed Al coating and Mg alloy substrate

    International Nuclear Information System (INIS)

    Wang, Qiang; Qiu, Dong; Xiong, Yuming; Birbilis, Nick; Zhang, Ming-Xing

    2014-01-01

    High-resolution transmission electron microscopy (HR-TEM) has validated the intimate metallurgical (atomic) bond formed along the interface of a cold-sprayed Al coating upon an Mg-alloy (AZ91) substrate. The compressive impact led to the formation of nanostructured layers of about 300–500 nm into the substrate. A highly distorted lattice structure with the inclusion of small amorphous zones was observed at the periphery of the particle/substrate interface, as a result of adiabatic shear plastic deformation at a high strain rate.

  1. Analysis of Polymorphic Nanocrystals of TiO2 by X-Ray Rietveld Refinement and High-Resolution Transmission Electron Microscopy: Acetaldehyde Decomposition

    Directory of Open Access Journals (Sweden)

    R. Carrera

    2008-01-01

    Full Text Available In this work, TiO2 nanocrystals were synthesized by the sol-gel method. These materials were annealed at 200 and 500∘C; and characterized by the XRD-Rietveld refinement; and by BET and TEM. As for the low-temperature-treated sample (200∘C, nanocrystals with small crystallite sizes (7 nm and high abundance of anatase, coexisting with the brookite phase, were obtained. Meanwhile, the sample annealed at 500∘C showed an increased crystallite size (22 nm and an important polymorphic increment. The sample annealed at 200∘C showed a high activity in the photocatalytic decomposition of acetaldehyde.

  2. A high resolution cross section transmission electron microscopy study of epitaxial rare earth fluoride/GaAs(111) interfaces prepared by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Chien, C.J.; Bravman, J.C.

    1990-01-01

    The authors report the HRXTEM study of epitaxial rare earth fluoride/GaAs(111) interfaces. Such interfaces are of interest because they are the starting point for growth of buried epitaxial rare earth/rare earth fluoride sandwich structures which exhibit interesting and non bulk-like magnetic properties. Also, the optical transitions in ultrathin epitaxial NdF 3 films may be influenced by strain and defects in the NdF 3 film and the nature of the interface to GaAs. The authors find that the rare earth fluoride/GaAs interfaces are semi-coherent but chemically abrupt with the transition taking place within 3 Angstrom. However, the interface is physically rough and multiple monolayer steps in the GaAs surface tend to tilt boundaries in the fluoride. The origin of these steps is believed to be thermal etching of the GaAs during the heat- cleaning stage prior to epitaxy. The surface of the fluoride film is much smoother than the initial GaAs surface indicating planarization during epitaxy

  3. Optimization of Beam Transmission of PAL-PNF Electron Linac

    Energy Technology Data Exchange (ETDEWEB)

    Shin, S. G.; Kim, S. K.; Kim, E. A. [Pohang University of Science and Technology, Pohang (Korea, Republic of)

    2012-05-15

    The PNF (Pohang Neutron Facility) electron Linac is providing converted neutrons and photons from electron beams to users for nuclear physics experiments and high energy gamma-ray exposures. This linac is capable of producing 100 MeV electron beams with a beam current of pulsed 100 mA. The pulse length is 2 {mu}s and the pulse repetition rate is typically 30 Hz. This linac consists of two SLAC-type S-band accelerating columns and the thermionic RF gun. They are powered by one klystron and the matching pulse modulator. The electron beams emitted from the RF gun are bunched as they pass through the alpha magnet and are injected into the accelerating column thereafter. In this paper, we discuss procedures and results of the beam transmission optimization with technical details of the accelerator system. We also briefly discuss the future upgrade plan to obtain short-pulse or electron beams for neutron TOF experiments by adopting a triode type thermionic DC electron gun

  4. Development of spin-polarized transmission electron microscope

    International Nuclear Information System (INIS)

    Kuwahara, M; Saitoh, K; Tanaka, N; Takeda, Y; Ujihara, T; Asano, H; Nakanishi, T

    2011-01-01

    In order to study spin related phenomena in nano-size materials, spin-polarized electron source (PES) has been employed for the incident beam in transmission electron microscope (TEM). The PES has been designed and constructed with optimizing for spin-polarized TEM. The illuminating system of TEM is also designed to focus the spin-polarized electron beam emitted from a semiconductor photocathode with a negative electron affinity (NEA) surface. The beam energy is set to below 40 keV which is lower energy type as a TEM, because the spin interaction with condensed matters is very small corresponding with a Coulomb interaction. The polarized electron gun has realized in an extra high vacuum (XHV) condition and high field gradient of 4 MV/m on a surface of photocathode. Furthermore, it demonstrated that 40-keV polarized electron beam was operated with a sub-milli second pulse mode by using the backside excitation type photocathode. This high performance PES will make it possible to observe dynamically a magnetic field images with high contrast and highspeed temporal imaging in TEM.

  5. High-resolution intravital microscopy.

    Directory of Open Access Journals (Sweden)

    Volker Andresen

    Full Text Available Cellular communication constitutes a fundamental mechanism of life, for instance by permitting transfer of information through synapses in the nervous system and by leading to activation of cells during the course of immune responses. Monitoring cell-cell interactions within living adult organisms is crucial in order to draw conclusions on their behavior with respect to the fate of cells, tissues and organs. Until now, there is no technology available that enables dynamic imaging deep within the tissue of living adult organisms at sub-cellular resolution, i.e. detection at the level of few protein molecules. Here we present a novel approach called multi-beam striped-illumination which applies for the first time the principle and advantages of structured-illumination, spatial modulation of the excitation pattern, to laser-scanning-microscopy. We use this approach in two-photon-microscopy--the most adequate optical deep-tissue imaging-technique. As compared to standard two-photon-microscopy, it achieves significant contrast enhancement and up to 3-fold improved axial resolution (optical sectioning while photobleaching, photodamage and acquisition speed are similar. Its imaging depth is comparable to multifocal two-photon-microscopy and only slightly less than in standard single-beam two-photon-microscopy. Precisely, our studies within mouse lymph nodes demonstrated 216% improved axial and 23% improved lateral resolutions at a depth of 80 µm below the surface. Thus, we are for the first time able to visualize the dynamic interactions between B cells and immune complex deposits on follicular dendritic cells within germinal centers (GCs of live mice. These interactions play a decisive role in the process of clonal selection, leading to affinity maturation of the humoral immune response. This novel high-resolution intravital microscopy method has a huge potential for numerous applications in neurosciences, immunology, cancer research and

  6. High-Resolution Intravital Microscopy

    Science.gov (United States)

    Andresen, Volker; Pollok, Karolin; Rinnenthal, Jan-Leo; Oehme, Laura; Günther, Robert; Spiecker, Heinrich; Radbruch, Helena; Gerhard, Jenny; Sporbert, Anje; Cseresnyes, Zoltan; Hauser, Anja E.; Niesner, Raluca

    2012-01-01

    Cellular communication constitutes a fundamental mechanism of life, for instance by permitting transfer of information through synapses in the nervous system and by leading to activation of cells during the course of immune responses. Monitoring cell-cell interactions within living adult organisms is crucial in order to draw conclusions on their behavior with respect to the fate of cells, tissues and organs. Until now, there is no technology available that enables dynamic imaging deep within the tissue of living adult organisms at sub-cellular resolution, i.e. detection at the level of few protein molecules. Here we present a novel approach called multi-beam striped-illumination which applies for the first time the principle and advantages of structured-illumination, spatial modulation of the excitation pattern, to laser-scanning-microscopy. We use this approach in two-photon-microscopy - the most adequate optical deep-tissue imaging-technique. As compared to standard two-photon-microscopy, it achieves significant contrast enhancement and up to 3-fold improved axial resolution (optical sectioning) while photobleaching, photodamage and acquisition speed are similar. Its imaging depth is comparable to multifocal two-photon-microscopy and only slightly less than in standard single-beam two-photon-microscopy. Precisely, our studies within mouse lymph nodes demonstrated 216% improved axial and 23% improved lateral resolutions at a depth of 80 µm below the surface. Thus, we are for the first time able to visualize the dynamic interactions between B cells and immune complex deposits on follicular dendritic cells within germinal centers (GCs) of live mice. These interactions play a decisive role in the process of clonal selection, leading to affinity maturation of the humoral immune response. This novel high-resolution intravital microscopy method has a huge potential for numerous applications in neurosciences, immunology, cancer research and developmental biology

  7. Three-Dimensional scanning transmission electron microscopy of biological specimens

    KAUST Repository

    De Jonge, Niels

    2010-01-18

    A three-dimensional (3D) reconstruction of the cytoskeleton and a clathrin-coated pit in mammalian cells has been achieved from a focal-series of images recorded in an aberration-corrected scanning transmission electron microscope (STEM). The specimen was a metallic replica of the biological structure comprising Pt nanoparticles 2-3 nm in diameter, with a high stability under electron beam radiation. The 3D dataset was processed by an automated deconvolution procedure. The lateral resolution was 1.1 nm, set by pixel size. Particles differing by only 10 nm in vertical position were identified as separate objects with greater than 20% dip in contrast between them. We refer to this value as the axial resolution of the deconvolution or reconstruction, the ability to recognize two objects, which were unresolved in the original dataset. The resolution of the reconstruction is comparable to that achieved by tilt-series transmission electron microscopy. However, the focal-series method does not require mechanical tilting and is therefore much faster. 3D STEM images were also recorded of the Golgi ribbon in conventional thin sections containing 3T3 cells with a comparable axial resolution in the deconvolved dataset. © 2010 Microscopy Society of America.

  8. Compact and high-resolution optical orbital angular momentum sorter

    Directory of Open Access Journals (Sweden)

    Chenhao Wan

    2017-03-01

    Full Text Available A compact and high-resolution optical orbital angular momentum (OAM sorter is proposed and demonstrated. The sorter comprises a quadratic fan-out mapper and a dual-phase corrector positioned in the pupil plane and the Fourier plane, respectively. The optical system is greatly simplified compared to previous demonstrations of OAM sorting, and the performance in resolution and efficiency is maintained. A folded configuration is set up using a single reflective spatial light modulator (SLM to demonstrate the validity of the scheme. The two phase elements are implemented on the left and right halves of the SLM and connected by a right-angle prism. Experimental results demonstrate the high resolution of the compact OAM sorter, and the current limit in efficiency can be overcome by replacing with transmissive SLMs and removing the beam splitters. This novel scheme paves the way for the miniaturization and integration of high-resolution OAM sorters.

  9. High-resolution spectroscopy of gases for industrial applications

    DEFF Research Database (Denmark)

    Fateev, Alexander; Clausen, Sønnik

    High-resolution spectroscopy of gases is a powerful technique which has various fundamental and practical applications: in situ simultaneous measurements of gas temperature and gas composition, radiative transfer modeling, validation of existing and developing of new databases and etc. Existing...... databases (e.g. HITRAN, HITEMP or CDSD) can normally be used for absorption spectra calculations at limited temperature/pressure ranges. Therefore experimental measurements of absorption/transmission spectra gases (e.g. CO2, H2O or SO2) at high-resolution and elevated temperatures are essential both...... for analysis of complex experimental data and further development of the databases. High-temperature gas cell facilities available at DTU Chemical Engineering are presented and described. The gas cells and high-resolution spectrometers allow us to perform high-quality reference measurements of gases relevant...

  10. Progress and applications of in situ transmission electron microscopy

    International Nuclear Information System (INIS)

    Wang Rongming; Liu Jialong; Song Yuanjun

    2015-01-01

    Recent progress in the application of in situ transmission electron microscopy (TEM) is briefly reviewed. It is emphasized that the development of advanced in situ TEM techniques makes it possible to investigate the evolution of materials under heat, strain, magnetic field, electric field or chemical reaction environments on the atomic scale. The mechanism of the microstructure evolution under various conditions and the relationship between the atomic structures and their properties can be obtained, which is beneficial for the design of new materials with tailored properties. The clarification of the structure-property relationship will help to develop new materials and solve related basic problems in the field of condensed matter physics. (authors)

  11. Characterization of catalysts by scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Targos, W.M.; Bradley, S.A.

    1989-01-01

    The dedicated scanning transmission electron microscope (STEM) is an integral tool for characterizing catalysts because of its unique ability to image and analyze nanosized volumes. This information is valuable in optimizing catalyst formulations and determining causes for reduced catalyst performance. For many commercial catalysts direct correlations between structural features of metal crystallites and catalytic performance are not attainable. When these instances occur, determination of elemental distribution may be the only information available. In this paper the authors discuss some of the techniques employed and limitations associated with characterizing commercial catalysts

  12. Fabrication and electric measurements of nanostructures inside transmission electron microscope.

    Science.gov (United States)

    Chen, Qing; Peng, Lian-Mao

    2011-06-01

    Using manipulation holders specially designed for transmission electron microscope (TEM), nanostructures can be characterized, measured, modified and even fabricated in-situ. In-situ TEM techniques not only enable real-time study of structure-property relationships of materials at atomic scale, but also provide the ability to control and manipulate materials and structures at nanoscale. This review highlights in-situ electric measurements and in-situ fabrication and structure modification using manipulation holder inside TEM. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Transmission electron microscopic study of reduced Ca2UO5

    International Nuclear Information System (INIS)

    Krasevec, V.; Prodan, A.; Holc, J.; Kolar, D.

    1983-01-01

    Structural changes of Ca 2 UO 5 during reduction in hydrogen were studied by transmission electron microscopy. It was shown that monoclinic Ca 2 UO 5 changes into triclinic Ca 4 U 2 O 9 . They are related, respectively, to the fluorite and the bixbyite (C-M 2 O 3 ) structures, so that the product is a superstructure of the latter. Reduction occurs along the (100)/sub t/ planes originating from the (006)/sub m/ planes of the parent structure by diminishing the coordination number of the Ca cation from 7 to 6. 5 figures

  14. Highlighting material structure with transmission electron diffraction correlation coefficient maps

    International Nuclear Information System (INIS)

    Kiss, Ákos K.; Rauch, Edgar F.; Lábár, János L.

    2016-01-01

    Correlation coefficient maps are constructed by computing the differences between neighboring diffraction patterns collected in a transmission electron microscope in scanning mode. The maps are shown to highlight material structural features like grain boundaries, second phase particles or dislocations. The inclination of the inner crystal interfaces are directly deduced from the resulting contrast. - Highlights: • We propose a novel technique to image the structure of polycrystalline TEM-samples. • Correlation coefficients maps highlights the evolution of the diffracting signal. • 3D views of grain boundaries are provided for nano-particles or polycrystals.

  15. Correction of bubble size distributions from transmission electron microscopy observations

    International Nuclear Information System (INIS)

    Kirkegaard, P.; Eldrup, M.; Horsewell, A.; Skov Pedersen, J.

    1996-01-01

    Observations by transmission electron microscopy of a high density of gas bubbles in a metal matrix yield a distorted size distribution due to bubble overlap and bubble escape from the surface. A model is described that reconstructs 3-dimensional bubble size distributions from 2-dimensional projections on taking these effects into account. Mathematically, the reconstruction is an ill-posed inverse problem, which is solved by regularization technique. Extensive Monte Carlo simulations support the validity of our model. (au) 1 tab., 32 ills., 32 refs

  16. Computer experiments on the imaging of point defects with the conventional transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Krakow, W [Xerox Corp., Rochester, N.Y. (USA)

    1978-02-01

    To aid in the interpretation of high resolution electron micrographs of defect structures in crystals, computer-simulated dark-field electron micrographs have been obtained for a variety of point defects in metals. Interpretation of these images in terms of atomic positions and atom correlations becomes straightforward, and it is a simple matter to distinguish between real structural information and image artifacts produced by the phase contrast mechanism in the electron optical imaging process.

  17. Transmission electron microscopy characterization of the interfacial structure of a galvanized dual-phase steel

    Energy Technology Data Exchange (ETDEWEB)

    Aslam, I., E-mail: ia31@msstate.edu [Center for Advanced Vehicular Systems, Mississippi State University, MS 39759 (United States); Department of Mechanical Engineering, Mississippi State University, MS 39762 (United States); Li, B. [Center for Advanced Vehicular Systems, Mississippi State University, MS 39759 (United States); Department of Chemical and Materials Engineering, University of Nevada, Reno, NV 89557 (United States); Martens, R.L.; Goodwin, J.R. [Central Analytical Facility, the University of Alabama, Tuscaloosa, AL 35487 (United States); Rhee, H.J. [Center for Advanced Vehicular Systems, Mississippi State University, MS 39759 (United States); Department of Mechanical Engineering, Mississippi State University, MS 39762 (United States); Goodwin, F. [International Zinc Association, Durham, NC 27713 (United States)

    2016-10-15

    Site-specific studies were carried out to characterize the interface of a galvanized dual-phase (DP) steel. Focused ion beam (FIB) was used to prepare specimens in the interface region (~ 100 nm thick) between the coating and the substrate. Transmission electron microscopy (TEM), scanning TEM (STEM), and high resolution TEM (HRTEM) were performed to resolve the phases and the structures at the interface between the zinc (Zn) coating and the steel substrate. The STEM and TEM results showed that a continuous manganese oxide (MnO) film with a thickness of ~ 20 nm was present on the surface of the substrate while no silicon (Si) oxides were resolved. Internal oxide particles were observed as well in the sub-surface region. Despite the presence of the continuous oxide film, a well-developed inhibition layer was observed right on top of the oxide film. The inhibition layer has a thickness of ~ 100 nm. Possible mechanisms for the growth of the inhibition layer were discussed. - Highlights: •Site-specific examinations were performed on the Zn/steel interface. •Continuous external MnO oxides (20 nm) were observed at the interface. •No Si oxides were observed at the interface. •Internal oxide particles were distributed in the subsurface. •A continuous inhibition layer grew on top of the external oxides.

  18. Structural defects in cubic semiconductors characterized by aberration-corrected scanning transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Arroyo Rojas Dasilva, Yadira; Kozak, Roksolana; Erni, Rolf; Rossell, Marta D., E-mail: marta.rossell@empa.ch

    2017-05-15

    The development of new electro-optical devices and the realization of novel types of transistors require a profound understanding of the structural characteristics of new semiconductor heterostructures. This article provides a concise review about structural defects which occur in semiconductor heterostructures on the basis of micro-patterned Si substrates. In particular, one- and two-dimensional crystal defects are being discussed which are due to the plastic relaxation of epitaxial strain caused by the misfit of crystal lattices. Besides a few selected examples from literature, we treat in particular crystal defects occurring in GaAs/Si, Ge/Si and β-SiC/Si structures which are studied by high-resolution annular dark-field scanning transmission electron microscopy. The relevance of this article is twofold; firstly, it should provide a collection of data which are of help for the identification and characterization of defects in cubic semiconductors by means of atomic-resolution imaging, and secondly, the experimental data shall provide a basis for advancing the understanding of device characteristics with the aid of theoretical modelling by considering the defective nature of strained semiconductor heterostructures. - Highlights: • The heterogeneous integration of high-quality compound semiconductors remains a challenge. • Lattice defects cause severe degradation of the semiconductor device performances. • Aberration-corrected HAADF-STEM allows atomic-scale characterization of defects. • An overview of lattice defects found in cubic semiconductors is presented. • Theoretical modelling and calculations are needed to determine the defect properties.

  19. Optical and Optoelectronic Property Analysis of Nanomaterials inside Transmission Electron Microscope.

    Science.gov (United States)

    Fernando, Joseph F S; Zhang, Chao; Firestein, Konstantin L; Golberg, Dmitri

    2017-12-01

    In situ transmission electron microscopy (TEM) allows one to investigate nanostructures at high spatial resolution in response to external stimuli, such as heat, electrical current, mechanical force and light. This review exclusively focuses on the optical, optoelectronic and photocatalytic studies inside TEM. With the development of TEMs and specialized TEM holders that include in situ illumination and light collection optics, it is possible to perform optical spectroscopies and diverse optoelectronic experiments inside TEM with simultaneous high resolution imaging of nanostructures. Optical TEM holders combining the capability of a scanning tunneling microscopy probe have enabled nanomaterial bending/stretching and electrical measurements in tandem with illumination. Hence, deep insights into the optoelectronic property versus true structure and its dynamics could be established at the nanometer-range precision thus evaluating the suitability of a nanostructure for advanced light driven technologies. This report highlights systems for in situ illumination of TEM samples and recent research work based on the relevant methods, including nanomaterial cathodoluminescence, photoluminescence, photocatalysis, photodeposition, photoconductivity and piezophototronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Transmission electron microscope studies of the nuclear envelope in Caenorhabditis elegans embryos.

    Science.gov (United States)

    Cohen, Merav; Tzur, Yonatan B; Neufeld, Esther; Feinstein, Naomi; Delannoy, Michael R; Wilson, Katherine L; Gruenbaum, Yosef

    2002-01-01

    Nuclear membranes and nuclear pore complexes (NPCs) are conserved in both animals and plants. However, the lamina composition and the dimensions of NPCs vary between plants, yeast, and vertebrates. In this study, we established a protocol that preserves the structure of Caenorhabditis elegans embryonic cells for high-resolution studies with thin-section transmission electron microscopy (TEM). We show that the NPCs are bigger in C. elegans embryos than in yeast, with dimensions similar to those in higher eukaryotes. We also localized the C. elegans nuclear envelope proteins Ce-lamin and Ce-emerin by pre-embedding gold labeling immunoelectron microscopy. Both proteins are present at or near the inner nuclear membrane. A fraction of Ce-lamin, but not Ce-emerin, is present in the nuclear interior. Removing the nuclear membranes leaves both Ce-lamin and Ce-emerin associated with the chromatin. Eliminating the single lamin protein caused cell death as visualized by characteristic changes in nuclear architecture including condensation of chromatin, clustering of NPCs, membrane blebbing, and the presence of vesicles inside the nucleus. Taken together, these results show evolutionarily conserved protein localization, interactions, and functions of the C. elegans nuclear envelope.

  1. High Resolution Scanning Ion Microscopy

    NARCIS (Netherlands)

    Castaldo, V.

    2011-01-01

    The structure of the thesis is the following. The first chapter is an introduction to scanning microscopy, where the path that led to the Focused Ion Beam (FIB) is described and the main differences between electrons and ion beams are highlighted. Chapter 2 is what is normally referred to (which I

  2. Microstructural differences between two Zr(C,N) coatings revealed by analytical transmission electron microscopy

    International Nuclear Information System (INIS)

    Dörfel, Ilona; Rooch, Heidemarie; Österle, Werner

    2012-01-01

    The microstructures of two samples of a Zr(C,N) coating on steel, which unexpectedly differed in their tribological properties, were investigated by analytical transmission electron microscopy. The samples were produced by a cathodic arc evaporation process in two commercial coating devices under similar coating conditions with the exception of the number of Zr targets. The source of the differing tribological properties of the samples was detected by analytical transmission electron microscopy (TEM) methods energy-dispersive X-ray spectroscopy (EDX), energy filtering TEM (EFTEM), electron diffraction, high resolution electron microscopy, and high angel annular dark field. The TEM preparation and the results of the TEM investigations are shown in detail. The origin of the unexpected behavior was determined to be a nano-scale multilayer structure that existed only in the tribologically superior specimen. EDX and EFTEM investigations indicated enrichment in oxygen at the interface between coating and steel substrate in the tribologically inferior sample. Findings of the microstructural configuration were obtained by taking a closer look at the structure and comparing the results of the several analytical TEM techniques. This allows the allocation of the concentration fluctuations in N, C, and Zr to the two thickness fractions of the nano multilayers and a local correlation of the identified minority phase Zr 3 (C,N) 4 to the higher N content in the narrower type of the multilayer fraction of the sample with the excellent tribological properties. The minority phase Zr 3 (C,N) 4 is randomly distributed in the sample with the defective tribological properties. Coating conditions are not topic of this work, but after discussion of the TEM results, the fact that one of the coating devices worked with one Zr target and the other one with two, could be identified as cause for the formation of the nano multilayer structure in the sample with the superior tribological

  3. In situ transmission electron microscopy for magnetic nanostructures

    DEFF Research Database (Denmark)

    Ngo, Duc-The; Kuhn, Luise Theil

    2016-01-01

    Nanomagnetism is a subject of great interest because of both application and fundamental aspects in which understanding of the physical and electromagnetic structure of magnetic nanostructures is essential to explore the magnetic properties. Transmission electron microscopy (TEM) is a powerful tool...... that allows understanding of both physical structure and micromagnetic structure of the thin samples at nanoscale. Among TEM techniques, in situ TEM is the state-of-the-art approach for imaging such structures in dynamic experiments, reconstructing a real-time nanoscale picture of the properties......-structure correlation. This paper aims at reviewing and discussing in situ TEM magnetic imaging studies, including Lorentz microscopy and electron holography in TEM, applied to the research of magnetic nanostructures....

  4. Imaging and Quantification of Extracellular Vesicles by Transmission Electron Microscopy.

    Science.gov (United States)

    Linares, Romain; Tan, Sisareuth; Gounou, Céline; Brisson, Alain R

    2017-01-01

    Extracellular vesicles (EVs) are cell-derived vesicles that are present in blood and other body fluids. EVs raise major interest for their diverse physiopathological roles and their potential biomedical applications. However, the characterization and quantification of EVs constitute major challenges, mainly due to their small size and the lack of methods adapted for their study. Electron microscopy has made significant contributions to the EV field since their initial discovery. Here, we describe the use of two transmission electron microscopy (TEM) techniques for imaging and quantifying EVs. Cryo-TEM combined with receptor-specific gold labeling is applied to reveal the morphology, size, and phenotype of EVs, while their enumeration is achieved after high-speed sedimentation on EM grids.

  5. Section on High Resolution Optical Imaging (HROI)

    Data.gov (United States)

    Federal Laboratory Consortium — The Section on High Resolution Optical Imaging (HROI) develops novel technologies for studying biological processes at unprecedented speed and resolution. Research...

  6. Ultra-precise measurement of optical aberrations for sub-Aangstroem transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Barthel, J.

    2008-06-15

    Quantitative investigations of material structures on an atomic scale by means of highresolution transmission electron microscopy (HRTEM) impose not only extreme demands on the mechanic and electromagnetic stability of the applied instruments but require also their precise electron-optical adjustment. Today a physical resolution well below one Aangstroem can be achieved with commercially available microscopes on a daily basis. However, the achieved resolution can often not be reliably exploited for the interpretation of the resulting microscopical data due to the presence of so-called higher-order lens aberrations. At the starting time of this work, a sufficiently accurate procedure to measure higher-order aberrations was urgently missing. Since aberration measurement is a mandatory prerequisite for any technique of aberration control enabling quantitative high-resolution microscopy, the goal of this work is to develop such a measurement procedure for the Sub-Aangstroem regime. The measurement procedures developed in the course of this work are based on the numerical evaluation of a series of images taken from an amorphous object under electron-beam illumination with varying tilt. New techniques have been developed for the evaluation of single images as well as for the optimised evaluation of the whole series. These procedures allow microscope users to perform quantitative HRTEM even at a resolution of 0.5 Aangstroem. The precision reached with the newly developed measurement procedures is unprecedented and surpasses existing solutions by at least one order of magnitude in any respect. All the concepts and procedures for aberration measurement developed in this work have been implemented in a software package which satisfies professional demands with respect to robustness, precision, speed and user-friendliness. The new automatic aberrationmeasurement procedures are suitable to establish HRTEM as a quantitative technique for material science investigations in the

  7. Ultra-precise measurement of optical aberrations for sub-Aangstroem transmission electron microscopy

    International Nuclear Information System (INIS)

    Barthel, J.

    2008-06-01

    Quantitative investigations of material structures on an atomic scale by means of highresolution transmission electron microscopy (HRTEM) impose not only extreme demands on the mechanic and electromagnetic stability of the applied instruments but require also their precise electron-optical adjustment. Today a physical resolution well below one Aangstroem can be achieved with commercially available microscopes on a daily basis. However, the achieved resolution can often not be reliably exploited for the interpretation of the resulting microscopical data due to the presence of so-called higher-order lens aberrations. At the starting time of this work, a sufficiently accurate procedure to measure higher-order aberrations was urgently missing. Since aberration measurement is a mandatory prerequisite for any technique of aberration control enabling quantitative high-resolution microscopy, the goal of this work is to develop such a measurement procedure for the Sub-Aangstroem regime. The measurement procedures developed in the course of this work are based on the numerical evaluation of a series of images taken from an amorphous object under electron-beam illumination with varying tilt. New techniques have been developed for the evaluation of single images as well as for the optimised evaluation of the whole series. These procedures allow microscope users to perform quantitative HRTEM even at a resolution of 0.5 Aangstroem. The precision reached with the newly developed measurement procedures is unprecedented and surpasses existing solutions by at least one order of magnitude in any respect. All the concepts and procedures for aberration measurement developed in this work have been implemented in a software package which satisfies professional demands with respect to robustness, precision, speed and user-friendliness. The new automatic aberrationmeasurement procedures are suitable to establish HRTEM as a quantitative technique for material science investigations in the

  8. Advances in imaging and electron physics the scanning transmission electron microscope

    CERN Document Server

    Hawkes, Peter W

    2009-01-01

    Advances in Imaging and Electron Physics merges two long-running serials--Advances in Electronics and Electron Physics and Advances in Optical and Electron Microscopy. This series features extended articles on the physics of electron devices (especially semiconductor devices), particle optics at high and low energies, microlithography, image science and digital image processing, electromagnetic wave propagation, electron microscopy, and the computing methods used in all these domains.  This particular volume presents several timely articles on the scanning transmission electron microscope. Updated with contributions from leading international scholars and industry experts Discusses hot topic areas and presents current and future research trends Provides an invaluable reference and guide for physicists, engineers and mathematicians.

  9. Interaction of electrons with light metal hydrides in the transmission electron microscope.

    Science.gov (United States)

    Wang, Yongming; Wakasugi, Takenobu; Isobe, Shigehito; Hashimoto, Naoyuki; Ohnuki, Somei

    2014-12-01

    Transmission electron microscope (TEM) observation of light metal hydrides is complicated by the instability of these materials under electron irradiation. In this study, the electron kinetic energy dependences of the interactions of incident electrons with lithium, sodium and magnesium hydrides, as well as the constituting element effect on the interactions, were theoretically discussed, and electron irradiation damage to these hydrides was examined using in situ TEM. The results indicate that high incident electron kinetic energy helps alleviate the irradiation damage resulting from inelastic or elastic scattering of the incident electrons in the TEM. Therefore, observations and characterizations of these materials would benefit from increased, instead decreased, TEM operating voltage. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Reconstruction and visualization of nanoparticle composites by transmission electron tomography

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.Y. [National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton, Canada T6H 2M9 (Canada); Department of Physics, University of Alberta, Edmonton, Canada T6G 2G7 (Canada); Lockwood, R. [National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton, Canada T6H 2M9 (Canada); Malac, M., E-mail: marek.malac@nrc-cnrc.gc.ca [National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton, Canada T6H 2M9 (Canada); Department of Physics, University of Alberta, Edmonton, Canada T6G 2G7 (Canada); Furukawa, H. [SYSTEM IN FRONTIER INC., 2-8-3, Shinsuzuharu bldg. 4F, Akebono-cho, Tachikawa-shi, Tokyo 190-0012 (Japan); Li, P.; Meldrum, A. [National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton, Canada T6H 2M9 (Canada)

    2012-02-15

    This paper examines the limits of transmission electron tomography reconstruction methods for a nanocomposite object composed of many closely packed nanoparticles. Two commonly used reconstruction methods in TEM tomography were examined and compared, and the sources of various artefacts were explored. Common visualization methods were investigated, and the resulting 'interpretation artefacts' ( i.e., deviations from 'actual' particle sizes and shapes arising from the visualization) were determined. Setting a known or estimated nanoparticle volume fraction as a criterion for thresholding does not in fact give a good visualization. Unexpected effects associated with common built-in image filtering methods were also found. Ultimately, this work set out to establish the common problems and pitfalls associated with electron beam tomographic reconstruction and visualization of samples consisting of closely spaced nanoparticles. -- Highlights: Black-Right-Pointing-Pointer Electron tomography limits were explored by both experiment and simulation. Black-Right-Pointing-Pointer Reliable quantitative volumetry using electron tomography is not presently feasible. Black-Right-Pointing-Pointer Volume rendering appears to be better choice for visualization of composite samples.

  11. Indium hydroxide to oxide decomposition observed in one nanocrystal during in situ transmission electron microscopy studies

    International Nuclear Information System (INIS)

    Miehe, Gerhard; Lauterbach, Stefan; Kleebe, Hans-Joachim; Gurlo, Aleksander

    2013-01-01

    The high-resolution transmission electron microscopy (HR-TEM) is used to study, in situ, spatially resolved decomposition in individual nanocrystals of metal hydroxides and oxyhydroxides. This case study reports on the decomposition of indium hydroxide (c-In(OH) 3 ) to bixbyite-type indium oxide (c-In 2 O 3 ). The electron beam is focused onto a single cube-shaped In(OH) 3 crystal of {100} morphology with ca. 35 nm edge length and a sequence of HR-TEM images was recorded during electron beam irradiation. The frame-by-frame analysis of video sequences allows for the in situ, time-resolved observation of the shape and orientation of the transformed crystals, which in turn enables the evaluation of the kinetics of c-In 2 O 3 crystallization. Supplementary material (video of the transformation) related to this article can be found online at (10.1016/j.jssc.2012.09.022). After irradiation the shape of the parent cube-shaped crystal is preserved, however, its linear dimension (edge) is reduced by the factor 1.20. The corresponding spotted selected area electron diffraction (SAED) pattern representing zone [001] of c-In(OH) 3 is transformed to a diffuse strongly textured ring-like pattern of c-In 2 O 3 that indicates the transformed cube is no longer a single crystal but is disintegrated into individual c-In 2 O 3 domains with the size of about 5–10 nm. The induction time of approximately 15 s is estimated from the time-resolved Fourier transforms. The volume fraction of the transformed phase (c-In 2 O 3 ), calculated from the shrinkage of the parent c-In(OH) 3 crystal in the recorded HR-TEM images, is used as a measure of the kinetics of c-In 2 O 3 crystallization within the framework of Avrami–Erofeev formalism. The Avrami exponent of ∼3 is characteristic for a reaction mechanism with fast nucleation at the beginning of the reaction and subsequent three-dimensional growth of nuclei with a constant growth rate. The structural transformation path in reconstructive

  12. Acquisition parameters optimization of a transmission electron forward scatter diffraction system in a cold-field emission scanning electron microscope for nanomaterials characterization.

    Science.gov (United States)

    Brodusch, Nicolas; Demers, Hendrix; Trudeau, Michel; Gauvin, Raynald

    2013-01-01

    Transmission electron forward scatter diffraction (t-EFSD) is a new technique providing crystallographic information with high resolution on thin specimens by using a conventional electron backscatter diffraction (EBSD) system in a scanning electron microscope. In this study, the impact of tilt angle, working distance, and detector distance on the Kikuchi pattern quality were investigated in a cold-field emission scanning electron microscope (CFE-SEM). We demonstrated that t-EFSD is applicable for tilt angles ranging from -20° to -40°. Working distance (WD) should be optimized for each material by choosing the WD for which the EBSD camera screen illumination is the highest, as the number of detected electrons on the screen is directly dependent on the scattering angle. To take advantage of the best performances of the CFE-SEM, the EBSD camera should be close to the sample and oriented towards the bottom to increase forward scattered electron collection efficiency. However, specimen chamber cluttering and beam/mechanical drift are important limitations in the CFE-SEM used in this work. Finally, the importance of t-EFSD in materials science characterization was illustrated through three examples of phase identification and orientation mapping. © Wiley Periodicals, Inc.

  13. The influence of Cs/Cc correction in analytical imaging and spectroscopy in scanning and transmission electron microscopy

    International Nuclear Information System (INIS)

    Zaluzec, Nestor J.

    2015-01-01

    Aberration correction in scanning/transmission electron microscopy (S/TEM) owes much to the efforts of a small dedicated group of innovators. Leading that frontier has been Prof. Harald Rose. To date his leadership and dynamic personality has spearheaded our ability to leave behind many of the limitations imposed by spherical aberration (C s ) in high resolution phase contrast imaging. Following shortly behind, has been the development of chromatic aberration correction (C c ) which augments those accomplishments. In this paper we will review and summarize how the combination of C s /C c technology enhances our ability to conduct hyperspectral imaging and spectroscopy in today's and future computationally mediated experiments in both thin as well as realistic specimens in vacuo and during in-situ/environmental experiments

  14. High-resolution CCD imaging alternatives

    Science.gov (United States)

    Brown, D. L.; Acker, D. E.

    1992-08-01

    High resolution CCD color cameras have recently stimulated the interest of a large number of potential end-users for a wide range of practical applications. Real-time High Definition Television (HDTV) systems are now being used or considered for use in applications ranging from entertainment program origination through digital image storage to medical and scientific research. HDTV generation of electronic images offers significant cost and time-saving advantages over the use of film in such applications. Further in still image systems electronic image capture is faster and more efficient than conventional image scanners. The CCD still camera can capture 3-dimensional objects into the computing environment directly without having to shoot a picture on film develop it and then scan the image into a computer. 2. EXTENDING CCD TECHNOLOGY BEYOND BROADCAST Most standard production CCD sensor chips are made for broadcast-compatible systems. One popular CCD and the basis for this discussion offers arrays of roughly 750 x 580 picture elements (pixels) or a total array of approximately 435 pixels (see Fig. 1). FOR. A has developed a technique to increase the number of available pixels for a given image compared to that produced by the standard CCD itself. Using an inter-lined CCD with an overall spatial structure several times larger than the photo-sensitive sensor areas each of the CCD sensors is shifted in two dimensions in order to fill in spatial gaps between adjacent sensors.

  15. Nano-structured thin films : a Lorentz transmission electron microscopy and electron holography study

    NARCIS (Netherlands)

    Hosson, J.Th.M. de; Raedt, H.A. De; Zhong, ZY; Saka, H; Kim, TH; Holm, EA; Han, YF; Xie, XS

    2005-01-01

    This paper aims at applying advanced transmission electron microscopy (TEM) to functional materials, such as ultra-soft magnetic films for high-frequency inductors, to reveal the structure-property relationship. The ultimate goal is to delineate a more quantitative way to obtain information of the

  16. In situ transmission electron microscopy and scanning transmission electron microscopy studies of sintering of Ag and Pt nanoparticles

    International Nuclear Information System (INIS)

    Asoro, M.A.; Ferreira, P.J.; Kovar, D.

    2014-01-01

    Transmission electron microscopy and scanning transmission electron microscopy studies were conducted in situ on 2–5 nm Pt and 10–40 nm Ag nanoparticles to study mechanisms for sintering and to measure relevant sintering kinetics in nanoscale particles. Sintering between two separated particles was observed to initiate by either (1) diffusion of the particles on the sample support or (2) diffusion of atoms or small clusters of atoms to the neck region between the two particles. After particle contact, the rate of sintering was controlled by atomic surface diffusivity. The surface diffusivity was determined as a function of particle size and temperature from experimental measurements of the rate of neck growth of the particles. The surface diffusivities did not show a strong size effect for the range of particle sizes that were studied. The surface diffusivity for Pt nanoparticles exhibited the expected Arrhenius temperature dependence and did not appear to be sensitive to the presence of surface contaminants. In contrast, the surface diffusivity for Ag nanoparticles was affected by the presence of impurities such as carbon. The diffusivities for Ag nanoparticles were consistent with previous measurements of bulk surface diffusivities for Ag in the presence of C, but were significantly slower than those obtained from pristine Ag

  17. High-resolution spectroscopy of gases for industrial applications

    OpenAIRE

    Fateev, Alexander; Clausen, Sønnik

    2012-01-01

    High-resolution spectroscopy of gases is a powerful technique which has various fundamental and practical applications: in situ simultaneous measurements of gas temperature and gas composition, radiative transfer modeling, validation of existing and developing of new databases and etc. Existing databases (e.g. HITRAN, HITEMP or CDSD) can normally be used for absorption spectra calculations at limited temperature/pressure ranges. Therefore experimental measurements of absorption/transmission s...

  18. Electron Source Brightness and Illumination Semi-Angle Distribution Measurement in a Transmission Electron Microscope.

    Science.gov (United States)

    Börrnert, Felix; Renner, Julian; Kaiser, Ute

    2018-05-21

    The electron source brightness is an important parameter in an electron microscope. Reliable and easy brightness measurement routes are not easily found. A determination method for the illumination semi-angle distribution in transmission electron microscopy is even less well documented. Herein, we report a simple measurement route for both entities and demonstrate it on a state-of-the-art instrument. The reduced axial brightness of the FEI X-FEG with a monochromator was determined to be larger than 108 A/(m2 sr V).

  19. Transmission electron microscopy in molecular structural biology: A historical survey.

    Science.gov (United States)

    Harris, J Robin

    2015-09-01

    In this personal, historic account of macromolecular transmission electron microscopy (TEM), published data from the 1940s through to recent times is surveyed, within the context of the remarkable progress that has been achieved during this time period. The evolution of present day molecular structural biology is described in relation to the associated biological disciplines. The contribution of numerous electron microscope pioneers to the development of the subject is discussed. The principal techniques for TEM specimen preparation, thin sectioning, metal shadowing, negative staining and plunge-freezing (vitrification) of thin aqueous samples are described, with a selection of published images to emphasise the virtues of each method. The development of digital image analysis and 3D reconstruction is described in detail as applied to electron crystallography and reconstructions from helical structures, 2D membrane crystals as well as single particle 3D reconstruction of icosahedral viruses and macromolecules. The on-going development of new software, algorithms and approaches is highlighted before specific examples of the historical progress of the structural biology of proteins and viruses are presented. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. A simple way to obtain backscattered electron images in a scanning transmission electron microscope.

    Science.gov (United States)

    Tsuruta, Hiroki; Tanaka, Shigeyasu; Tanji, Takayoshi; Morita, Chiaki

    2014-08-01

    We have fabricated a simple detector for backscattered electrons (BSEs) and incorporated the detector into a scanning transmission electron microscope (STEM) sample holder. Our detector was made from a 4-mm(2) Si chip. The fabrication procedure was easy, and similar to a standard transmission electron microscopy (TEM) sample thinning process based on ion milling. A TEM grid containing particle objects was fixed to the detector with a silver paste. Observations were carried out using samples of Au and latex particles at 75 and 200 kV. Such a detector provides an easy way to obtain BSE images in an STEM. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Investigation of superthermal asymmetric electron distributions using electron cyclotron wave transmission in tokamaks

    International Nuclear Information System (INIS)

    Giruzzi, G.; Fidone, I.; Marcha, M.J.

    1991-01-01

    The asymmetric electron distribution generated during lower hybrid current drive has been computed using a 3-D Fokker-Planck code. The superthermal tail and the resulting current are generally a combination of two components streaming in opposite toroidal directions. An appropriate diagnostic method for experimental investigation of the two superthermal populations is wave transmission of two equivalent rays with equal and opposite values of the refractive index. These equivalent rays can be realized by launching the waves from symmetric positions with respect ot the equatorial plane at equal and opposite angles in the toroidal direction. Using an appropriate ray tracing code, the damping of the two rays is computed and it is shown that it results from electrons with opposite parallel velocities. The differential transmission is then a measure of the overall asymmetry of the electron momentum distribution. (author). 12 refs, 8 figs

  2. Secondary Electron Emission Materials for Transmission Dynodes in Novel Photomultipliers: A Review

    Directory of Open Access Journals (Sweden)

    Shu Xia Tao

    2016-12-01

    Full Text Available Secondary electron emission materials are reviewed with the aim of providing guidelines for the future development of novel transmission dynodes. Materials with reflection secondary electron yield higher than three and transmission secondary electron yield higher than one are tabulated for easy reference. Generations of transmission dynodes are listed in the order of the invention time with a special focus on the most recent atomic-layer-deposition synthesized transmission dynodes. Based on the knowledge gained from the survey of secondary election emission materials with high secondary electron yield, an outlook of possible improvements upon the state-of-the-art transmission dynodes is provided.

  3. Direct Visualization of Local Electromagnetic Field Structures by Scanning Transmission Electron Microscopy.

    Science.gov (United States)

    Shibata, Naoya; Findlay, Scott D; Matsumoto, Takao; Kohno, Yuji; Seki, Takehito; Sánchez-Santolino, Gabriel; Ikuhara, Yuichi

    2017-07-18

    The functional properties of materials and devices are critically determined by the electromagnetic field structures formed inside them, especially at nanointerface and surface regions, because such structures are strongly associated with the dynamics of electrons, holes and ions. To understand the fundamental origin of many exotic properties in modern materials and devices, it is essential to directly characterize local electromagnetic field structures at such defect regions, even down to atomic dimensions. In recent years, rapid progress in the development of high-speed area detectors for aberration-corrected scanning transmission electron microscopy (STEM) with sub-angstrom spatial resolution has opened new possibilities to directly image such electromagnetic field structures at very high-resolution. In this Account, we give an overview of our recent development of differential phase contrast (DPC) microscopy for aberration-corrected STEM and its application to many materials problems. In recent years, we have developed segmented-type STEM detectors which divide the detector plane into 16 segments and enable simultaneous imaging of 16 STEM images which are sensitive to the positions and angles of transmitted/scattered electrons on the detector plane. These detectors also have atomic-resolution imaging capability. Using these segmented-type STEM detectors, we show DPC STEM imaging to be a very powerful tool for directly imaging local electromagnetic field structures in materials and devices in real space. For example, DPC STEM can clearly visualize the local electric field variation due to the abrupt potential change across a p-n junction in a GaAs semiconductor, which cannot be observed by normal in-focus bright-field or annular type dark-field STEM imaging modes. DPC STEM is also very effective for imaging magnetic field structures in magnetic materials, such as magnetic domains and skyrmions. Moreover, real-time imaging of electromagnetic field structures can

  4. Evolution of dislocation structures following a change in loading conditions studied by in situ high resolution reciprocal space mapping

    DEFF Research Database (Denmark)

    Wejdemann, Christian

    or to a strain of 7% at a temperature of -196 ○C, and the samples were characterized by electron microscopy and mechanical tests. Transmission electron microscopy showed that the pre-deformation produced a characteristic dislocation cell structure consisting of regions with relatively high dislocation density...... the pre-deformation axis. In the X-ray diffraction experiments a technique was employed with which it is possible to obtain high-resolution reciprocal space maps from individual bulk grains. The high-resolution reciprocal space maps contain features related to the dislocation structure in the grains......: A spread-out ‘cloud’ of low intensity caused by diffraction from the dislocation walls and a number of sharp peaks of high intensity caused by diffraction from the individual subgrains. By acquiring reciprocal space maps at a number of different strain levels the evolution of the dislocation structures can...

  5. Transmission electron microscopy characterization of photocatalysts for water splitting

    DEFF Research Database (Denmark)

    Cavalca, Filippo; Laursen, Anders Bo; Dahl, Søren

    , it is necessary to understand the fundamentals of their reaction mechanisms, chemical behavior, structure and morphology before, during and after reaction using in situ investigations. Here, we focus on the in situ characterization of photocatalysts [1] in an environmental transmission electron microscope (ETEM......) [2]. Such fundamental insight can be used for further material optimization with respect to performance and stability [3]. In this work, we combine conventional TEM analysis of photocatalysts with environmental TEM (ETEM) and photoactivation using light. A novel type of TEM specimen holder...... that enables in situ illumination is developed to study light-induced phenomena in photoactive materials at the nanoscale under working conditions. Our experiments are aimed at exposing a specimen to light and detecting resulting microstructural and chemical changes using in situ TEM techniques...

  6. Transmission electron microscopy analysis of hydroxyapatite nanocrystals from cattle bones

    International Nuclear Information System (INIS)

    Patel, Sangeeta; Wei, Shanghai; Han, Jie; Gao, Wei

    2015-01-01

    In this present study, hydroxyapatite which was obtained from cattle bones has been heat treated at temperature 400 °C and 600 °C. The microstructure after the treatment has been studied in detail using Transmission electron microscopy (TEM) and X-ray diffraction techniques. The TEM results indicate that natural bone consists of collagen and hydroxyapatite nano-crystals which are needle shaped. The heat treatment influences the crystallinity and growth of these hydroxyapatite nano-crystals known as ‘crystal maturation’ or ‘crystal ageing’. - Highlights: • Hydroxyapatite is obtained from cattle bones. • Material has been characterised using XRD and TEM. • Crystal growth and orientation has been studied in detail.

  7. Transmission electron microscope sample holder with optical features

    Science.gov (United States)

    Milas, Mirko [Port Jefferson, NY; Zhu, Yimei [Stony Brook, NY; Rameau, Jonathan David [Coram, NY

    2012-03-27

    A sample holder for holding a sample to be observed for research purposes, particularly in a transmission electron microscope (TEM), generally includes an external alignment part for directing a light beam in a predetermined beam direction, a sample holder body in optical communication with the external alignment part and a sample support member disposed at a distal end of the sample holder body opposite the external alignment part for holding a sample to be analyzed. The sample holder body defines an internal conduit for the light beam and the sample support member includes a light beam positioner for directing the light beam between the sample holder body and the sample held by the sample support member.

  8. Transmission electron microscope cells for use with liquid samples

    Science.gov (United States)

    Khalid, Waqas; Alivisatos, Paul A.; Zettl, Alexander K.

    2016-08-09

    This disclosure provides systems, methods, and devices related to transmission electron microscopy cells for use with liquids. In one aspect a device includes a substrate, a first graphene layer, and a second graphene layer. The substrate has a first surface and a second surface. The first surface defines a first channel, a second channel, and an outlet channel. The first channel and the second channel are joined to the outlet channel. The outlet channel defines a viewport region forming a though hole in the substrate. The first graphene layer overlays the first surface of the substrate, including an interior area of the first channel, the second channel, and the outlet channel. The second graphene layer overlays the first surface of the substrate, including open regions defined by the first channel, the second channel, and the outlet channel.

  9. Transmission electron microscopy analysis of hydroxyapatite nanocrystals from cattle bones

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Sangeeta, E-mail: spt658@aucklanduni.ac.nz [Department of Chemical and Materials Engineering, The University of Auckland, 20 Symonds Street, Auckland 1010 (New Zealand); Wei, Shanghai [Department of Chemical and Materials Engineering, The University of Auckland, 20 Symonds Street, Auckland 1010 (New Zealand); Han, Jie [Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Avenue, Urbana, IL (United States); Gao, Wei [Department of Chemical and Materials Engineering, The University of Auckland, 20 Symonds Street, Auckland 1010 (New Zealand)

    2015-11-15

    In this present study, hydroxyapatite which was obtained from cattle bones has been heat treated at temperature 400 °C and 600 °C. The microstructure after the treatment has been studied in detail using Transmission electron microscopy (TEM) and X-ray diffraction techniques. The TEM results indicate that natural bone consists of collagen and hydroxyapatite nano-crystals which are needle shaped. The heat treatment influences the crystallinity and growth of these hydroxyapatite nano-crystals known as ‘crystal maturation’ or ‘crystal ageing’. - Highlights: • Hydroxyapatite is obtained from cattle bones. • Material has been characterised using XRD and TEM. • Crystal growth and orientation has been studied in detail.

  10. Fabrication and electric measurements of nanostructures inside transmission electron microscope

    International Nuclear Information System (INIS)

    Chen, Qing; Peng, Lian-Mao

    2011-01-01

    Using manipulation holders specially designed for transmission electron microscope (TEM), nanostructures can be characterized, measured, modified and even fabricated in-situ. In-situ TEM techniques not only enable real-time study of structure-property relationships of materials at atomic scale, but also provide the ability to control and manipulate materials and structures at nanoscale. This review highlights in-situ electric measurements and in-situ fabrication and structure modification using manipulation holder inside TEM. -- Research highlights: → We review in-situ works using manipulation holder in TEM. → In-situ electric measurements, fabrication and structure modification are focused. → We discuss important issues that should be considered for reliable results. → In-situ TEM is becoming a very powerful tool for many research fields.

  11. Ultrastructural instability of paired helical filaments from corticobasal degeneration as examined by scanning transmission electron microscopy.

    Science.gov (United States)

    Ksiezak-Reding, H.; Tracz, E.; Yang, L. S.; Dickson, D. W.; Simon, M.; Wall, J. S.

    1996-01-01

    Paired helical filaments (PHFs) accumulate in the brains of subjects affected with Alzheimer's disease (AD) and certain other neurodegenerative disorders, including corticobasal degeneration (CBD). Electron microscope studies have shown that PHFs from CBD differ from those of AD by being wider and having a longer periodicity of the helical twist. Moreover, PHFs from CBD have been shown to be primarily composed of two rather than three highly phosphorylated polypeptides of tau (PHF-tau), with these polypeptides expressing no exons 3 and 10. To further explore the relationship between the heterogeneity of PHF-tau and the appearance of abnormal filaments, the ultrastructure and physical parameters such as mass per unit length and dimensions were compared in filaments from CBD and AD using high resolution scanning transmission electron microscopy (STEM). Filament-enriched fractions were isolated as Sarcosyl-insoluble pellets and for STEM studies, samples were freeze-dried without prior fixation or staining. Ultrastructurally, PHFs from CBD were shown to be a heterogeneous population as double- and single-stranded filaments could be identified based on their width and physical mass per unit length expressed in kilodaltons (kd) per nanometer (nm). Less abundant, double-stranded filaments had a maximal width of 29 nm and a mass per unit length of 133 kd/nm, whereas three times more abundant single-stranded filaments were 15 nm wide and bad a mass per unit length of 62 kd/nm. Double-stranded filaments also displayed a distinct axial region of less dense mass, which appeared to divide the PHFs into two protofilament-like strands. Furthermore, these filaments were frequently observed to physically separate along the long axis into two single strands or to break longitudinally. In contrast, PHFs from AD were ultrastructurally stable and uniform both in their width (22 nm) and physical mass per unit length (104 kd/nm). The ultrastructural features indicate that filaments of

  12. Study of electron transmission through thin metallic films by the electron moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Babikova, Yu.F.; Vakar, O.M.; Gruzin, O.M.; Petrikin, Yu.V.

    1983-01-01

    Results of the experimental study of the transmission of conversion electrons through aluminium, iron, tin and gold films are presented. Absorption of resonance electrons of the Moessbauer nuclide 57 Fe, formed during target irradiation with γ-quanta of 57 Co source in chromium matrix has been studied. It is asserted that absorption of conversion electrons in films of different elements is similar; at that, like in the case of β-particles, the law of absorption of resonance electrons, emitted from the flat layer, is exponential For conversion electrons of the Moessbauer nuclide 57 Fe the absorption coefficient is (0.025+-0.002) cm 2 /μg, which in the case of iron absorbing film corresponds to (20.0+-1.0)x10 4 cm -1

  13. Optimized cleanup method for the determination of short chain polychlorinated n-alkanes in sediments by high resolution gas chromatography/electron capture negative ion-low resolution mass spectrometry

    International Nuclear Information System (INIS)

    Gao Yuan; Zhang Haijun; Chen Jiping; Zhang Qing; Tian Yuzeng; Qi Peipei; Yu Zhengkun

    2011-01-01

    Graphical abstract: The sediment sample could be purified by the optimized cleanup method, and satisfying cleanup efficiency was obtained. Highlights: → The elution characters of sPCAs and interfering substances were evaluated on three adsorbents. → An optimized cleanup method was developed for sPCAs with satisfying cleanup efficiency. → The cleanup method combined with HRGC/ECNI-LRMS was applied for sPCAs analysis. → The sPCAs levels range from 53.6 ng g -1 to 289.3 ng g -1 in tested sediment samples. - Abstract: The performances of three adsorbents, i.e. silica gel, neutral and basic alumina, in the separation of short chain polychlorinated n-alkanes (sPCAs) from potential interfering substances such as polychlorinated biphenyls (PCBs) and organochlorine pesticides were evaluated. To increase the cleanup efficiency, a two-step cleanup method using silica gel column and subsequent basic alumina column was developed. All the PCB and organochlorine pesticides could be removed by this cleanup method. The very satisfying cleanup efficiency of sPCAs has been achieved and the recovery in the cleanup method reached 92.7%. The method detection limit (MDL) for sPCAs in sediments was determined to be 14 ng g -1 . Relative standard deviation (R.S.D.) of 5.3% was obtained for the mass fraction of sPCAs by analyzing four replicates of a spiked sediment sample. High resolution gas chromatography/electron capture negative ion-low resolution mass spectrometry (HRGC/ECNI-LRMS) was used for sPCAs quantification by monitoring [M-HCl]· - ions. When applied to the sediment samples from the mouth of the Daliao River, the optimized cleanup method in conjunction with HRGC/ECNI-LRMS allowed for highly selective identifications for sPCAs. The sPCAs levels in sediment samples are reported to range from 53.6 ng g -1 to 289.3 ng g -1 . C 10 - and C 11 -PCAs are the dominant residue in most of investigated sediment samples.

  14. High-Resolution Integrated Optical System

    Science.gov (United States)

    Prakapenka, V. B.; Goncharov, A. F.; Holtgrewe, N.; Greenberg, E.

    2017-12-01

    Raman and optical spectroscopy in-situ at extreme high pressure and temperature conditions relevant to the planets' deep interior is a versatile tool for characterization of wide range of properties of minerals essential for understanding the structure, composition, and evolution of terrestrial and giant planets. Optical methods, greatly complementing X-ray diffraction and spectroscopy techniques, become crucial when dealing with light elements. Study of vibrational and optical properties of minerals and volatiles, was a topic of many research efforts in past decades. A great deal of information on the materials properties under extreme pressure and temperature has been acquired including that related to structural phase changes, electronic transitions, and chemical transformations. These provide an important insight into physical and chemical states of planetary interiors (e.g. nature of deep reservoirs) and their dynamics including heat and mass transport (e.g. deep carbon cycle). Optical and vibrational spectroscopy can be also very instrumental for elucidating the nature of the materials molten states such as those related to the Earth's volatiles (CO2, CH4, H2O), aqueous fluids and silicate melts, planetary ices (H2O, CH4, NH3), noble gases, and H2. The optical spectroscopy study performed concomitantly with X-ray diffraction and spectroscopy measurements at the GSECARS beamlines on the same sample and at the same P-T conditions would greatly enhance the quality of this research and, moreover, will provide unique new information on chemical state of matter. The advanced high-resolution user-friendly integrated optical system is currently under construction and expected to be completed by 2018. In our conceptual design we have implemented Raman spectroscopy with five excitation wavelengths (266, 473, 532, 660, 946 nm), confocal imaging, double sided IR laser heating combined with high temperature Raman (including coherent anti-Stokes Raman scattering) and

  15. Development of wave length-dispersive soft x-ray emission spectrometers for transmission electron microscopes - an introduction of valence electron spectroscopy for transmission electron microscopy

    International Nuclear Information System (INIS)

    Terauchi, Masami; Koike, Masato; Fukushima, Kurio; Kimura, Atsushi

    2010-01-01

    Two types of wavelength-dispersive soft X-ray spectrometers, a high-dispersion type and a conventional one, for transmission electron microscopes were constructed. Those spectrometers were used to study the electronic states of valence electrons (bonding electrons). Both spectrometers extended the acceptable energy regions to higher than 2000 eV. The best energy resolution of 0.08 eV was obtained for an Al L-emission spectrum by using the high-dispersion type spectrometer. By using the spectrometer, C K-emission of carbon allotropes, Cu L-emission of Cu 1-x Zn x alloys and Pt M-emission spectra were presented. The FWHM value of 12 eV was obtained for the Pt Mα-emission peak. The performance of the conventional one was also presented for ZnS and a section specimen of a multilayer device. W-M and Si-K emissions were clearly resolved. Soft X-ray emission spectroscopy based on transmission electron microscopy (TEM) has an advantage for obtaining spectra from a single crystalline specimen with a defined crystal setting. As an example of anisotropic soft X-ray emission, C K-emission spectra of single crystalline graphite with different crystal settings were presented. From the spectra, density of states of π- and σ-bondings were separately derived. These results demonstrated a method to analyse the electronic states of valence electrons of materials in the nanometre scale based on TEM. (author)

  16. Scanning transmission electron microscopy: Albert Crewe's vision and beyond

    International Nuclear Information System (INIS)

    Krivanek, Ondrej L.; Chisholm, Matthew F.; Murfitt, Matthew F.; Dellby, Niklas

    2012-01-01

    Some four decades were needed to catch up with the vision that Albert Crewe and his group had for the scanning transmission electron microscope (STEM) in the nineteen sixties and seventies: attaining 0.5 Å resolution, and identifying single atoms spectroscopically. With these goals now attained, STEM developments are turning toward new directions, such as rapid atomic resolution imaging and exploring atomic bonding and electronic properties of samples at atomic resolution. The accomplishments and the future challenges are reviewed and illustrated with practical examples. -- Highlights: ► TV-rate STEM imaging of heavy atoms is demonstrated. ► DNA sequencing by STEM dark field imaging should be possible at a rate of 10 6 bases/s. ► Individual silicon atom impurities in graphene are imaged atom-by-atom. ► Single atoms of nitrogen and boron incorporated in graphene are imaged spectroscopically. ► Bonding of individual atoms can be probed by analyzing the fine structures of their EEL spectra.

  17. Transmission electron microscopy a textbook for materials science

    CERN Document Server

    Williams, David B

    1996-01-01

    Electron microscopy has revolutionized our understanding the extraordinary intellectual demands required of the mi­ of materials by completing the processing-structure-prop­ croscopist in order to do the job properly: crystallography, erties links down to atomistic levels. It now is even possible diffraction, image contrast, inelastic scattering events, and to tailor the microstructure (and meso structure ) of materials spectroscopy. Remember, these used to be fields in them­ to achieve specific sets of properties; the extraordinary abili­ selves. Today, one has to understand the fundamentals ties of modem transmission electron microscopy-TEM­ of all of these areas before one can hope to tackle signifi­ instruments to provide almost all of the structural, phase, cant problems in materials science. TEM is a technique of and crystallographic data allow us to accomplish this feat. characterizing materials down to the atomic limits. It must Therefore, it is obvious that any curriculum in modem mate­ be use...

  18. Investigation of C3 S hydration mechanism by transmission electron microscope (TEM) with integrated Super-XTM EDS system.

    Science.gov (United States)

    Sakalli, Y; Trettin, R

    2017-07-01

    Tricalciumsilicate (C 3 S, Alite) is the major component of the Portland cement clinker. Hydration of Alite is decisive in influencing the properties of the resulting material. This is due to its high content in cement. The mechanism of the hydration of C 3 S is very complicated and not yet fully understood. There are different models describing the hydration of C 3 S in various ways. In this work for a better understanding of hydration mechanism, the hydrated C 3 S was investigated by using the transmission electron microscope (TEM) and for the first time, the samples for the investigations were prepared by using of focused ion beam from sintered pellets of C 3 S. Also, an FEI Talos F200x with an integrated Super-X EDS system was used for the investigations. FEI Talos F200X combines outstanding high-resolution S/TEM and TEM imaging with energy dispersive X-ray spectroscopy signal detection, and 3D chemical characterization with compositional mapping. TEM is a very powerful tool for material science. A high energy beam of electrons passes through a very thin sample, and the interactions between the electrons and the atoms can be used to observe the structure of the material and other features in the structure. TEM can be used to study the growth of layers and their composition. TEM produces high-resolution, two-dimensional images and will be used for a wide range of educational, science and industry applications. Chemical analysis can also be performed. The purpose of these investigations was to get the information about the composition of the C-S-H phases and some details of the nanostructure of the C-S-H phases. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  19. Strain fields around dislocation arrays in a Σ9 silicon bicrystal measured by scanning transmission electron microscopy

    Science.gov (United States)

    Couillard, Martin; Radtke, Guillaume; Botton, Gianluigi A.

    2013-04-01

    Strain fields around grain boundary dislocations are measured by applying geometric phase analysis on atomic resolution images obtained from multiple fast acquisitions in scanning transmission electron microscopy. Maps of lattice distortions in silicon introduced by an array of pure edge dislocations located at a Σ9(122) grain boundary are compared with the predictions from isotropic elastic theory, and the atomic structure of dislocation cores is deduced from images displaying all the atomic columns. For strain measurements, reducing the acquisition time is found to significantly decrease the effects of instabilities on the high-resolution images. Contributions from scanning artefacts are also diminished by summing multiple images following a cross-correlation alignment procedure. Combined with the sub-Ångström resolution obtained with an aberration corrector, and the stable dedicated microscope's environment, therapid acquisition method provides the measurements of atomic displacements with accuracy below 10 pm. Finally, the advantages of combining strain measurements with the collection of various analytical signals in a scanning transmission electron microscope are discussed.

  20. High resolution sequence stratigraphy in China

    International Nuclear Information System (INIS)

    Zhang Shangfeng; Zhang Changmin; Yin Yanshi; Yin Taiju

    2008-01-01

    Since high resolution sequence stratigraphy was introduced into China by DENG Hong-wen in 1995, it has been experienced two development stages in China which are the beginning stage of theory research and development of theory research and application, and the stage of theoretical maturity and widely application that is going into. It is proved by practices that high resolution sequence stratigraphy plays more and more important roles in the exploration and development of oil and gas in Chinese continental oil-bearing basin and the research field spreads to the exploration of coal mine, uranium mine and other strata deposits. However, the theory of high resolution sequence stratigraphy still has some shortages, it should be improved in many aspects. The authors point out that high resolution sequence stratigraphy should be characterized quantitatively and modelized by computer techniques. (authors)

  1. High resolution CT of the chest

    Energy Technology Data Exchange (ETDEWEB)

    Barneveld Binkhuysen, F H [Eemland Hospital (Netherlands), Dept. of Radiology

    1996-12-31

    Compared to conventional CT high resolution CT (HRCT) shows several extra anatomical structures which might effect both diagnosis and therapy. The extra anatomical structures were discussed briefly in this article. (18 refs.).

  2. High-resolution spectrometer at PEP

    International Nuclear Information System (INIS)

    Weiss, J.M.; HRS Collaboration.

    1982-01-01

    A description is presented of the High Resolution Spectrometer experiment (PEP-12) now running at PEP. The advanced capabilities of the detector are demonstrated with first physics results expected in the coming months

  3. Transmission Electron Microscopy of Magnetite Plaquettes in Orgueil

    Science.gov (United States)

    Chan, Q. H. S.; Han, J.; Zolensky, M.

    2016-01-01

    Magnetite sometimes takes the form of a plaquette - barrel-shaped stack of magnetite disks - in carbonaceous chondrites (CC) that show evidence of aqueous alteration. The asymmetric nature of the plaquettes caused Pizzarello and Groy to propose magnetite plaquettes as a naturally asymmetric mineral that can indroduce symmetry-breaking in organic molecules. Our previous synchrotron X-ray computed microtomography (SXRCT) and electron backscatter diffraction (EBSD) analyses of the magnetite plaquettes in fifteen CCs indicate that magnetite plaquettes are composed of nearly parallel discs, and the crystallographic orientations of the discs change around a rotational axis normal to the discs surfaces. In order to further investigate the nanostructures of magnetite plaquettes, we made two focused ion beam (FIB) sections of nine magnetite plaquettes from a thin section of CI Orgueil for transmission electron microscope (TEM) analysis. The X-ray spectrum imaging shows that the magnetite discs are purely iron oxide Fe3O4 (42.9 at% Fe and 57.1 at% O), which suggest that the plaquettes are of aqueous origin as it is difficult to form pure magnetite as a nebular condensate. The selected area electron diffraction (SAED) patterns acquired across the plaquettes show that the magnetite discs are single crystals. SEM and EBSD analyses suggest that the planar surfaces of the magnetite discs belong to the {100} planes of the cubic inverse spinel structure, which are supported by our TEM observations. Kerridge et al. suggested that the epitaxial relationship between magnetite plaquette and carbonate determines the magnetite face. However, according to our TEM observation, the association of magnetite with porous networks of phyllosilicate indicates that the epitaxial relationship with carbonate is not essential to the formation of magnetite plaquettes. It was difficult to determine the preferred rotational orientation of the plaquettes due to the symmetry of the cubic structure

  4. Structure of high-resolution NMR spectra

    CERN Document Server

    Corio, PL

    2012-01-01

    Structure of High-Resolution NMR Spectra provides the principles, theories, and mathematical and physical concepts of high-resolution nuclear magnetic resonance spectra.The book presents the elementary theory of magnetic resonance; the quantum mechanical theory of angular momentum; the general theory of steady state spectra; and multiple quantum transitions, double resonance and spin echo experiments.Physicists, chemists, and researchers will find the book a valuable reference text.

  5. Digital acquisition and processing of electron micrographs using a scanning transmission electron microscope

    International Nuclear Information System (INIS)

    Engel, A.; Christen, F.; Michel, B.

    1981-01-01

    A digital acquisition system that collects multichannel information from a scanning transmission electron microscope (STEM) and its application are described. The hardware comprises (i) single electron counting detectors, (ii) a digital scan generator, (iii) a digital multi-channel on-line processor, (iv) an interface to a minicomputer, and (v) a display system. Experimental results characterizing these components are presented, and their performance is discussed. The software includes assembler coded programs for dynamic file maintenance and fast acquisition of image data, a display driver, and FORTRAN coded application programs. The usefulness of digitized STEM is illustrated by a variety of biological applications. (orig.)

  6. Nature of mixed symmetry 2+ states in 94Mo from high resolution electron and proton scattering and line shape of the first excited 1/2+ state in 9Be

    International Nuclear Information System (INIS)

    Burda, Oleksiy

    2007-07-01

    The present work contains two parts. The first one is devoted to the investigation of mixed-symmetry structure in 94 Mo and the second one to the astrophysical relevant line shape of the first excited 1/2 + state in 9 Be. In the first part of the thesis the nature of one- and two-phonon symmetric and mixed-symmetric 2 + states in 94 Mo is investigated with high-resolution inelastic electron and proton scattering experiments in a combined analysis. The (e,e') experiments were carried out at the 169 magnetic spectrometer at the S-DALINAC. Data were taken at a beam energy E e=70 MeV and scattering angles Θ e =93 -165 . In dispersion-matching mode an energy resolution Δ E =30-45 keV (full width at half maximum) was achieved. The (p,p') measurements were performed at iThemba LABS, South Africa, using a K600 magnetic spectrometer at a proton energy E p=200 MeV and scattering angles Θ p =4.5 -26 . Typical energy resolutions were Δ E ≅35 keV. The combined analysis reveals a dominant one-phonon structure of the transitions to the first and third 2 + states, as well as an isovector character of the transition to the one-phonon mixed-symmetric state within the valence shell. Quantitatively consistent estimates of the one-phonon admixtures are obtained from both experimental probes when two-step contributions to the proton scattering cross sections are taken into account. In the second part of the thesis the line shape of the first excited 1/2 + state in 9 Be is studied. Spectra of the 9 Be(e,e') reaction were measured at the S-DALINAC at an electron energy E e=73 MeV and scattering angles of 93 and 141 with high energy resolution up to excitation energies E x =8 MeV. The form factor of the first excited state has been extracted from the data. The astrophysical relevant 9 Be(γ,n) cross sections have been extracted from the (e,e') data. The resonance parameters of the first excited 1/2 + state in 9 Be are derived in a one-level R-matrix approximation. The deduced

  7. Nature of mixed symmetry 2{sup +} states in {sup 94}Mo from high resolution electron and proton scattering and line shape of the first excited 1/2{sup +} state in {sup 9}Be

    Energy Technology Data Exchange (ETDEWEB)

    Burda, Oleksiy

    2007-07-15

    The present work contains two parts. The first one is devoted to the investigation of mixed-symmetry structure in {sup 94}Mo and the second one to the astrophysical relevant line shape of the first excited 1/2{sup +} state in {sup 9}Be. In the first part of the thesis the nature of one- and two-phonon symmetric and mixed-symmetric 2{sup +} states in {sup 94}Mo is investigated with high-resolution inelastic electron and proton scattering experiments in a combined analysis. The (e,e') experiments were carried out at the 169 magnetic spectrometer at the S-DALINAC. Data were taken at a beam energy E e=70 MeV and scattering angles {theta}{sub e}=93 -165 . In dispersion-matching mode an energy resolution {delta}{sub E}=30-45 keV (full width at half maximum) was achieved. The (p,p') measurements were performed at iThemba LABS, South Africa, using a K600 magnetic spectrometer at a proton energy E p=200 MeV and scattering angles {theta}{sub p}=4.5 -26 . Typical energy resolutions were {delta}{sub E}{approx_equal}35 keV. The combined analysis reveals a dominant one-phonon structure of the transitions to the first and third 2{sup +} states, as well as an isovector character of the transition to the one-phonon mixed-symmetric state within the valence shell. Quantitatively consistent estimates of the one-phonon admixtures are obtained from both experimental probes when two-step contributions to the proton scattering cross sections are taken into account. In the second part of the thesis the line shape of the first excited 1/2{sup +} state in {sup 9}Be is studied. Spectra of the {sup 9}Be(e,e') reaction were measured at the S-DALINAC at an electron energy E e=73 MeV and scattering angles of 93 and 141 with high energy resolution up to excitation energies E{sub x}=8 MeV. The form factor of the first excited state has been extracted from the data. The astrophysical relevant {sup 9}Be({gamma},n) cross sections have been extracted from the (e,e') data. The

  8. Electron beam dynamics in an ultrafast transmission electron microscope with Wehnelt electrode.

    Science.gov (United States)

    Bücker, K; Picher, M; Crégut, O; LaGrange, T; Reed, B W; Park, S T; Masiel, D J; Banhart, F

    2016-12-01

    High temporal resolution transmission electron microscopy techniques have shown significant progress in recent years. Using photoelectron pulses induced by ultrashort laser pulses on the cathode, these methods can probe ultrafast materials processes and have revealed numerous dynamic phenomena at the nanoscale. Most recently, the technique has been implemented in standard thermionic electron microscopes that provide a flexible platform for studying material's dynamics over a wide range of spatial and temporal scales. In this study, the electron pulses in such an ultrafast transmission electron microscope are characterized in detail. The microscope is based on a thermionic gun with a Wehnelt electrode and is operated in a stroboscopic photoelectron mode. It is shown that the Wehnelt bias has a decisive influence on the temporal and energy spread of the picosecond electron pulses. Depending on the shape of the cathode and the cathode-Wehnelt distance, different emission patterns with different pulse parameters are obtained. The energy spread of the pulses is determined by space charge and Boersch effects, given by the number of electrons in a pulse. However, filtering effects due to the chromatic aberrations of the Wehnelt electrode allow the extraction of pulses with narrow energy spreads. The temporal spread is governed by electron trajectories of different length and in different electrostatic potentials. High temporal resolution is obtained by excluding shank emission from the cathode and aberration-induced halos in the emission pattern. By varying the cathode-Wehnelt gap, the Wehnelt bias, and the number of photoelectrons in a pulse, tradeoffs between energy and temporal resolution as well as beam intensity can be made as needed for experiments. Based on the characterization of the electron pulses, the optimal conditions for the operation of ultrafast TEMs with thermionic gun assembly are elaborated. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Indium hydroxide to oxide decomposition observed in one nanocrystal during in situ transmission electron microscopy studies

    Science.gov (United States)

    Miehe, Gerhard; Lauterbach, Stefan; Kleebe, Hans-Joachim; Gurlo, Aleksander

    2013-02-01

    The high-resolution transmission electron microscopy (HR-TEM) is used to study, in situ, spatially resolved decomposition in individual nanocrystals of metal hydroxides and oxyhydroxides. This case study reports on the decomposition of indium hydroxide (c-In(OH)3) to bixbyite-type indium oxide (c-In2O3). The electron beam is focused onto a single cube-shaped In(OH)3 crystal of {100} morphology with ca. 35 nm edge length and a sequence of HR-TEM images was recorded during electron beam irradiation. The frame-by-frame analysis of video sequences allows for the in situ, time-resolved observation of the shape and orientation of the transformed crystals, which in turn enables the evaluation of the kinetics of c-In2O3 crystallization. Supplementary material (video of the transformation) related to this article can be found online at 10.1016/j.jssc.2012.09.022. After irradiation the shape of the parent cube-shaped crystal is preserved, however, its linear dimension (edge) is reduced by the factor 1.20. The corresponding spotted selected area electron diffraction (SAED) pattern representing zone [001] of c-In(OH)3 is transformed to a diffuse strongly textured ring-like pattern of c-In2O3 that indicates the transformed cube is no longer a single crystal but is disintegrated into individual c-In2O3 domains with the size of about 5-10 nm. The induction time of approximately 15 s is estimated from the time-resolved Fourier transforms. The volume fraction of the transformed phase (c-In2O3), calculated from the shrinkage of the parent c-In(OH)3 crystal in the recorded HR-TEM images, is used as a measure of the kinetics of c-In2O3 crystallization within the framework of Avrami-Erofeev formalism. The Avrami exponent of ˜3 is characteristic for a reaction mechanism with fast nucleation at the beginning of the reaction and subsequent three-dimensional growth of nuclei with a constant growth rate. The structural transformation path in reconstructive decomposition of c-In(OH)3 to c

  10. Collaborative Research and Development. Delivery Order 0006: Transmission Electron Microscope Image Modeling and Semiconductor Heterointerface Characterization

    National Research Council Canada - National Science Library

    Mahalingam, Krishnamurthy

    2006-01-01

    .... Transmission electron microscope (TEM) characterization studies were performed on a variety of novel III-V semiconductor heterostructures being developed for advanced optoelectronic device applications...

  11. Transmission electron microscopy investigations of the CdSe based quantum structures

    International Nuclear Information System (INIS)

    Roventa, E.

    2006-01-01

    In this work, the structural morphology of the active region of the ZnSe laser diode: quaternary CdZnSSe quantum well or CdSe quantum dots embedded in CdSe/ZnSSe superlattices is investigated using Transmission Electron Microscopy. The conventional as well as high resolution imaging studies indicated that the degradation of the ZnSe laser diodes is connected with the formation of extended defects in the optical active region leading to a local strain relaxation of the quantum well. Furthermore the outdiffusion of Cd from the quantum well occurs predominantly where the defects are located. The chemical composition and ordering phenomena in CdSe/ZnSSe supperlattices were also investigated, employing a series of five-fold structures with different spacer layer thickness and a ten-fold structure. The composition in the CdSe/ZnSSe superlattice was determined to a certain extent using different techniques. Generally, the encountered difficulties regarding the accuracy of the obtained values are correlated with the complexity of the investigated system and with the available experimental methods used. Regarding the alignment of the dots, experimental results support a strain driven ordering process, in which the strain fields from buried dots lead to heterogeneous nucleation conditions for the dots in the subsequently deposited layers. An increased ordering with subsequent stacking of the dot layers is was also found. An anisotropy of the lateral alignment of the CdSe dots was also observed in two different left angle 110 right angle zone axes. The similar plan-view images shows that the preferential alignment of the dots does not follow low-index crystallographic directions. However, it is assumed that this is attributed to the anisotropic elastic strain distribution combined with surface diffusion. (orig.)

  12. Transmission electron microscopy investigations of the CdSe based quantum structures

    Energy Technology Data Exchange (ETDEWEB)

    Roventa, E.

    2006-09-22

    In this work, the structural morphology of the active region of the ZnSe laser diode: quaternary CdZnSSe quantum well or CdSe quantum dots embedded in CdSe/ZnSSe superlattices is investigated using Transmission Electron Microscopy. The conventional as well as high resolution imaging studies indicated that the degradation of the ZnSe laser diodes is connected with the formation of extended defects in the optical active region leading to a local strain relaxation of the quantum well. Furthermore the outdiffusion of Cd from the quantum well occurs predominantly where the defects are located. The chemical composition and ordering phenomena in CdSe/ZnSSe supperlattices were also investigated, employing a series of five-fold structures with different spacer layer thickness and a ten-fold structure. The composition in the CdSe/ZnSSe superlattice was determined to a certain extent using different techniques. Generally, the encountered difficulties regarding the accuracy of the obtained values are correlated with the complexity of the investigated system and with the available experimental methods used. Regarding the alignment of the dots, experimental results support a strain driven ordering process, in which the strain fields from buried dots lead to heterogeneous nucleation conditions for the dots in the subsequently deposited layers. An increased ordering with subsequent stacking of the dot layers is was also found. An anisotropy of the lateral alignment of the CdSe dots was also observed in two different left angle 110 right angle zone axes. The similar plan-view images shows that the preferential alignment of the dots does not follow low-index crystallographic directions. However, it is assumed that this is attributed to the anisotropic elastic strain distribution combined with surface diffusion. (orig.)

  13. AIMgSil Alloy Characterization Using Transmission Electron Microscope (TEM)

    International Nuclear Information System (INIS)

    Masrukan; Elman, P.

    1996-01-01

    The aging alloy of AIMgSil containing Mg 2 Si of 1.29 % has been done with the following steps: e.q (a) part of the specimen was heated at 400 o C during 3 hours, and (b) the other part was done with solution treatment at 550 o C followed by quenching. After quenching a part of the specimen was aged at room temperature and other specimen was aged at 160 o C during 16 hours. After the specimen had been heated, then it was shaped into thin foil to be examined by Transmission Electron Microscope. The result showed that the heating at temperature of 400 o C during 3 hours created a second phase (i.e.Mg 2 Si) was like stick shape with the hexagonal structure at [0111] orientation and matrix [001], and the hardness was 31 HB. The aging of specimen at room temperature gave result a GP zone which was like the needles shape in the dislocation area of the face center cubic structure at [111] orientation and [111] matrix. The hardness obtained was 64 HB. In the other hand the aging process at temperature of 160 o C within 16 hours have resulted the precipitate which was greater than that of the former needle shaped as the face center cubic structure without dislocation at matrix with [111] orientation and [114] matrix. The hardness at this condition was 94 HB

  14. Visualizing aquatic bacteria by light and transmission electron microscopy.

    Science.gov (United States)

    Silva, Thiago P; Noyma, Natália P; Duque, Thabata L A; Gamalier, Juliana P; Vidal, Luciana O; Lobão, Lúcia M; Chiarini-Garcia, Hélio; Roland, Fábio; Melo, Rossana C N

    2014-01-01

    The understanding of the functional role of aquatic bacteria in microbial food webs is largely dependent on methods applied to the direct visualization and enumeration of these organisms. While the ultrastructure of aquatic bacteria is still poorly known, routine observation of aquatic bacteria by light microscopy requires staining with fluorochromes, followed by filtration and direct counting on filter surfaces. Here, we used a new strategy to visualize and enumerate aquatic bacteria by light microscopy. By spinning water samples from varied tropical ecosystems in a cytocentrifuge, we found that bacteria firmly adhere to regular slides, can be stained by fluorochoromes with no background formation and fast enumerated. Significant correlations were found between the cytocentrifugation and filter-based methods. Moreover, preparations through cytocentrifugation were more adequate for bacterial viability evaluation than filter-based preparations. Transmission electron microscopic analyses revealed a morphological diversity of bacteria with different internal and external structures, such as large variation in the cell envelope and capsule thickness, and presence or not of thylakoid membranes. Our results demonstrate that aquatic bacteria represent an ultrastructurally diverse population and open avenues for easy handling/quantification and better visualization of bacteria by light microscopy without the need of filter membranes.

  15. Reference nano-dimensional metrology by scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Dai, Gaoliang; Fluegge, Jens; Bosse, Harald; Heidelmann, Markus; Kübel, Christian; Prang, Robby

    2013-01-01

    Traceable and accurate reference dimensional metrology of nano-structures by scanning transmission electron microscopy (STEM) is introduced in the paper. Two methods, one based on the crystal lattice constant and the other based on the pitch of a feature pair, were applied to calibrate the TEM magnification. The threshold value, which was defined as the half-intensity of boundary materials, is suggested to extract the boundary position of features from the TEM image. Experimental investigations have demonstrated the high potential of the proposed methods. For instance, the standard deviation from ten repeated measurements of a line structure with a nominal 100 nm critical dimension (CD) reaches 1σ = 0.023 nm, about 0.02%. By intentionally introduced defocus and larger sample alignment errors, the investigation shows that these influences may reach 0.20 and 1.3 nm, respectively, indicating the importance of high-quality TEM measurements. Finally, a strategy for disseminating the destructive TEM results is introduced. Using this strategy, the CD of a reference material has been accurately determined. Its agreement over five independent TEM measurements is below 1.2 nm. (paper)

  16. Transmission electron microscopy of weakly deformed alkali halide crystals

    International Nuclear Information System (INIS)

    Strunk, H.

    1976-01-01

    Transmission electron microscopy (TEM) is applied to the investigation of the dislocation arrangement of [001]-orientated alkali halide crystals (orientation four quadruple slip) deformed into stage I of the work-hardenig curve. The investigations pertain mainly to NaCl - (0.1-1) mole-% NaBr crystals, because these exhibit a relatively long stage I. The time available for observing the specimens is limited by the ionization radiation damage occuring in the microscope. An optimum reduction of the damage rate is achieved by a combination of several experimental techniques that are briefly outlined. The crystals deform essentially in single glide. According to the observations, stage I deformation of pure and weakly alloyed NaCl crystals is characterized by the glide of screw dislocations, which bow out between jogs and drag dislocation dipoles behind them. In crystals with >= 0.5 mole-% NaBr this process is not observed to occur. This is attributed to the increased importance of solid solution hardening. (orig.) [de

  17. Electron beam dynamics in an ultrafast transmission electron microscope with Wehnelt electrode

    Energy Technology Data Exchange (ETDEWEB)

    Bücker, K.; Picher, M.; Crégut, O. [Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 CNRS, Université de Strasbourg, 23 rue du Loess, 67034 Strasbourg (France); LaGrange, T. [Interdisciplinary Centre for Electron Microscopy, École Polytechnique Fédérale de Lausanne, 1015 Lausanne (Switzerland); Reed, B.W.; Park, S.T.; Masiel, D.J. [Integrated Dynamic Electron Solutions, Inc., 5653 Stoneridge Drive 117, Pleasanton, CA 94588 (United States); Banhart, F., E-mail: florian.banhart@ipcms.unistra.fr [Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 CNRS, Université de Strasbourg, 23 rue du Loess, 67034 Strasbourg (France)

    2016-12-15

    High temporal resolution transmission electron microscopy techniques have shown significant progress in recent years. Using photoelectron pulses induced by ultrashort laser pulses on the cathode, these methods can probe ultrafast materials processes and have revealed numerous dynamic phenomena at the nanoscale. Most recently, the technique has been implemented in standard thermionic electron microscopes that provide a flexible platform for studying material's dynamics over a wide range of spatial and temporal scales. In this study, the electron pulses in such an ultrafast transmission electron microscope are characterized in detail. The microscope is based on a thermionic gun with a Wehnelt electrode and is operated in a stroboscopic photoelectron mode. It is shown that the Wehnelt bias has a decisive influence on the temporal and energy spread of the picosecond electron pulses. Depending on the shape of the cathode and the cathode-Wehnelt distance, different emission patterns with different pulse parameters are obtained. The energy spread of the pulses is determined by space charge and Boersch effects, given by the number of electrons in a pulse. However, filtering effects due to the chromatic aberrations of the Wehnelt electrode allow the extraction of pulses with narrow energy spreads. The temporal spread is governed by electron trajectories of different length and in different electrostatic potentials. High temporal resolution is obtained by excluding shank emission from the cathode and aberration-induced halos in the emission pattern. By varying the cathode-Wehnelt gap, the Wehnelt bias, and the number of photoelectrons in a pulse, tradeoffs between energy and temporal resolution as well as beam intensity can be made as needed for experiments. Based on the characterization of the electron pulses, the optimal conditions for the operation of ultrafast TEMs with thermionic gun assembly are elaborated. - Highlights: • A detailed characterization of electron

  18. Transmission electron microscopy of carbon-coated and iron-doped titania nanoparticles

    KAUST Repository

    Anjum, Dalaver H.

    2016-08-02

    We present a study on the properties of iron (Fe)-doped and carbon (C)-coated titania (TiO2) nanoparticles (NPs) which has been compiled by using x-ray diffraction (XRD), transmission electron microscopy (TEM), and x-ray photoelectron spectroscopy (XPS). These TiO2 NPs were prepared by using the flame synthesis method. This method allows the simultaneous C coating and Fe doping of TiO2 NPs. XRD investigations revealed that the phase of the prepared NPs was anatase TiO2. Conventional TEM analysis showed that the average size of the TiO2 NPs was about 65 nm and that the NPs were uniformly coated with the element C. Furthermore, from the x-ray energy dispersive spectrometry analysis, it was found that about 8 at.% Fe was present in the synthesized samples. High-resolution TEM (HRTEM) revealed the graphitized carbon structure of the layer surrounding the prepared TiO2 NPs. HRTEM analysis further revealed that the NPs possessed the crystalline structure of anatase titania. Energy-filtered TEM (EFTEM) analysis showed the C coating and Fe doping of the NPs. The ratio of L3 and L2 peaks for the Ti-L23 and Fe-L23 edges present in the core loss electron energy loss spectroscopy (EELS) revealed a +4 oxidation state for the Ti and a +3 oxidation state for the Fe. These EELS results were further confirmed with XPS analysis. The electronic properties of the samples were investigated by applying Kramers-Kronig analysis to the low-loss EELS spectra acquired from the prepared NPs. The presented results showed that the band gap energy of the TiO2 NPs decreased from an original value of 3.2 eV to about 2.2 eV, which is quite close to the ideal band gap energy of 1.65 eV for photocatalysis semiconductors. The observed decrease in band gap energy of the TiO2 NPs was attributed to the presence of Fe atoms at the lattice sites of the anatase TiO2 lattice. In short, C-coated and Fe-doped TiO2 NPs were synthesized with a rather cost-effective and comparatively easily scalable method. The

  19. Transmission electron microscopic study of pyrochlore to defect-fluorite transition in rare-earth pyrohafnates

    Energy Technology Data Exchange (ETDEWEB)

    Karthik, Chinnathambi, E-mail: Karthikchinnathambi@boisestate.edu [Department of Materials Science and Engineering, Boise State University, 1910 University drive, Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd, Idaho Falls, ID 83415 (United States); Anderson, Thomas J. [Department of Materials Science and Engineering, Boise State University, 1910 University drive, Boise, ID 83725 (United States); Gout, Delphine [Oak Ridge National Lab, Neutron Scattering Science Division, Oak Ridge, TN (United States); Ubic, Rick [Department of Materials Science and Engineering, Boise State University, 1910 University drive, Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Blvd, Idaho Falls, ID 83415 (United States)

    2012-10-15

    A structural transition in rare earth pyrohafnates, Ln{sub 2}Hf{sub 2}O{sub 7} (Ln=Y, La, Pr, Nd, Tb, Dy, Yb and Lu), has been identified. Neutron diffraction showed that the structure transforms from well-ordered pyrochloric to fully fluoritic through the lanthanide series from La to Lu with a corresponding increase in the position parameter x of the 48f (Fd3{sup Macron }m) oxygen site from 0.330 to 0.375. As evidenced by the selected area electron diffraction, La{sub 2}Hf{sub 2}O{sub 7}, Pr{sub 2}Hf{sub 2}O{sub 7} and Nd{sub 2}Hf{sub 2}O{sub 7} exhibited a well-ordered pyrocholoric structure with the presence of intense superlattice spots, which became weak and diffuse (in Dy{sub 2}Hf{sub 2}O{sub 7} and Tb{sub 2}Hf{sub 2}O{sub 7}) before disappearing completely as the series progressed towards the Lu end. High resolution electron microscopic studies showed the breakdown of the pyrochlore ordering in the form of antiphase domains resulting in diffused smoke-like superlattice spots in the case of Dy{sub 2}Hf{sub 2}O{sub 7} and Tb{sub 2}Hf{sub 2}O{sub 7}. - Graphical abstract: Transmission electron microscopic studies showed the ordered pyrochlore to defect fluorite transition in rare-earth pyrohafnates to occur via the formation of anti-phase domains to start with. Highlights: Black-Right-Pointing-Pointer Pyrochlore to fluorite structural transition in rare earth pyrohafnates. Black-Right-Pointing-Pointer La{sub 2}Hf{sub 2}O{sub 7}, Pr{sub 2}Hf{sub 2}O{sub 7} and Nd{sub 2}Hf{sub 2}O{sub 7} showed well ordered pyrochlore structure. Black-Right-Pointing-Pointer Short range ordering in Dy{sub 2}Hf{sub 2}O{sub 7} and Tb{sub 2}Hf{sub 2}O{sub 7}. Black-Right-Pointing-Pointer Break down of pyrochlore ordering due to antiphase boundaries. Black-Right-Pointing-Pointer Rest of the series showed fluoritic structure.

  20. A high resolution large dynamic range TDC circuit implementation

    International Nuclear Information System (INIS)

    Lei Wuhu; Liu Songqiu; Ye Weiguo; Han Hui; Li Pengyu

    2003-01-01

    Time measurement technology is usually used in nuclear experimentation. There are many methods of time measurement. The implementation method of Time to Digital Conversion (TDC) by means of electronic is a classical technology. The range and resolution of TDC is different according with different usage. A wide range and high resolution TDC circuit, including its theory and implementation way, is introduced in this paper. The test result is also given. (authors)

  1. A high resolution large dynamic range TDC circuit implementation

    International Nuclear Information System (INIS)

    Lei Wuhu; Liu Songqiu; Li Pengyu; Han Hui; Ye Yanlin

    2005-01-01

    Time measurement technology is usually used in nuclear experimentation. There are many methods of time measurement. The implementation method of Time to Digital Conversion (TDC) by means of electronics is a classical technology. The range and resolution of TDC is different according with different usage. A wide range and high resolution TDC circuit, including its theory and implementation way, is introduced in this paper. The test result is also given. (authors)

  2. High resolution atomic spectra of rare earths : progress report

    International Nuclear Information System (INIS)

    Saksena, G.D.; Ahmad, S.A.

    1976-01-01

    High resolution studies of atomic spectra of neodymium and gadolinium are being carried out on a recording Fabry-Perot spectrometer. The present progress report concerns work done on new assignments as well as confirmation of recently assigned electronic configurations and evaluation of isotope shifts of energy levels which have been possible from the isotope shift data obtained for several transitions of NdI, NdII and GdI, GdII respectively. (author)

  3. High resolution solar soft X-ray spectrometer

    International Nuclear Information System (INIS)

    Zhang Fei; Wang Huanyu; Peng Wenxi; Liang Xiaohua; Zhang Chunlei; Cao Xuelei; Jiang Weichun; Zhang Jiayu; Cui Xingzhu

    2012-01-01

    A high resolution solar soft X-ray spectrometer (SOX) payload onboard a satellite is developed. A silicon drift detector (SDD) is adopted as the detector of the SOX spectrometer. The spectrometer consists of the detectors and their readout electronics, a data acquisition unit and a payload data handling unit. A ground test system is also developed to test SOX. The test results show that the design goals of the spectrometer system have been achieved. (authors)

  4. Tunable electronic transmission gaps in a graphene superlattice

    International Nuclear Information System (INIS)

    Lu Weitao; Wang Shunjin; Li Wen; Wang Yonglong; Jiang Hua

    2012-01-01

    The transmission in graphene superlattices with adjustable barrier height is investigated using transfer-matrix method. It is found that one could control the angular range of transmission by changing the ratio of incidence energy and barrier height. The transmission as a function of incidence energy has more than one gaps, due to the appearance of evanescent waves in different barriers. Accordingly, more than one conductivity minimums are induced. The transmission gaps could be controlled by adjusting the incidence angle, the barrier height, and the barrier number, which gives the possibility to construct an energy-dependent wavevector filter.

  5. Experimental system for high resolution X-ray transmission radiography

    Czech Academy of Sciences Publication Activity Database

    Jakůbek, J.; Holý, T.; Jakůbek, M.; Vavřík, Daniel; Vykydal, Z.

    Volume 563, č. 1 (2006), s. 278-281 ISSN 0168-9002. [Intern. Workshop on Radiation Imaging Detectors /7./. Grenoble, 04.07.2005-07.07.2005] R&D Projects: GA MŠk(CZ) 1P04LA211; GA ČR(CZ) GA106/04/0567 Institutional research plan: CEZ:AV0Z20710524 Keywords : digital radiography * beam hardening * mikroradiography * roentgenogram quality Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 1.185, year: 2006

  6. Effects of lattice fluctuations on electronic transmission in metal/conjugated-oligomer/metal structures

    International Nuclear Information System (INIS)

    Yu, Z.G.; Smith, D.L.; Saxena, A.; Bishop, A.R.

    1997-01-01

    The electronic transmission across metal/conjugated-oligomer/metal structures in the presence of lattice fluctuations is studied for short oligomer chains. The lattice fluctuations are approximated by static white noise disorder. Resonant transmission occurs when the energy of an incoming electron coincides with a discrete electronic level of the oligomer. The corresponding transmission peak diminishes in intensity with increasing disorder strength. Because of disorder there is an enhancement of the electronic transmission for energies that lie within the electronic gap of the oligomer. If fluctuations are sufficiently strong, a transmission peak within the gap is found at the midgap energy E=0 for degenerate conjugated oligomers (e.g., trans-polyacetylene) and E≠0 for AB-type degenerate oligomers. These results can be interpreted in terms of soliton-antisoliton states created by lattice fluctuations. copyright 1997 The American Physical Society

  7. Bright-field scanning confocal electron microscopy using a double aberration-corrected transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peng; Behan, Gavin; Kirkland, Angus I. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Nellist, Peter D., E-mail: peter.nellist@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Cosgriff, Eireann C.; D' Alfonso, Adrian J.; Morgan, Andrew J.; Allen, Leslie J. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Hashimoto, Ayako [Advanced Nano-characterization Center, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba 305-0003 (Japan); Takeguchi, Masaki [Advanced Nano-characterization Center, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba 305-0003 (Japan); High Voltage Electron Microscopy Station, NIMS, 3-13 Sakura, Tsukuba 305-0003 (Japan); Mitsuishi, Kazutaka [Advanced Nano-characterization Center, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba 305-0003 (Japan); Quantum Dot Research Center, NIMS, 3-13 Sakura, Tsukuba 305-0003 (Japan); Shimojo, Masayuki [High Voltage Electron Microscopy Station, NIMS, 3-13 Sakura, Tsukuba 305-0003 (Japan); Advanced Science Research Laboratory, Saitama Institute of Technology, 1690 Fusaiji, Fukaya 369-0293 (Japan)

    2011-06-15

    Scanning confocal electron microscopy (SCEM) offers a mechanism for three-dimensional imaging of materials, which makes use of the reduced depth of field in an aberration-corrected transmission electron microscope. The simplest configuration of SCEM is the bright-field mode. In this paper we present experimental data and simulations showing the form of bright-field SCEM images. We show that the depth dependence of the three-dimensional image can be explained in terms of two-dimensional images formed in the detector plane. For a crystalline sample, this so-called probe image is shown to be similar to a conventional diffraction pattern. Experimental results and simulations show how the diffracted probes in this image are elongated in thicker crystals and the use of this elongation to estimate sample thickness is explored. -- Research Highlights: {yields} The confocal probe image in a scanning confocal electron microscopy image reveals information about the thickness and height of the crystalline layer. {yields} The form of the contrast in a three-dimensional bright-field scanning confocal electron microscopy image can be explained in terms of the confocal probe image. {yields} Despite the complicated form of the contrast in bright-field scanning confocal electron microscopy, we see that depth information is transferred on a 10 nm scale.

  8. Bright-field scanning confocal electron microscopy using a double aberration-corrected transmission electron microscope.

    Science.gov (United States)

    Wang, Peng; Behan, Gavin; Kirkland, Angus I; Nellist, Peter D; Cosgriff, Eireann C; D'Alfonso, Adrian J; Morgan, Andrew J; Allen, Leslie J; Hashimoto, Ayako; Takeguchi, Masaki; Mitsuishi, Kazutaka; Shimojo, Masayuki

    2011-06-01

    Scanning confocal electron microscopy (SCEM) offers a mechanism for three-dimensional imaging of materials, which makes use of the reduced depth of field in an aberration-corrected transmission electron microscope. The simplest configuration of SCEM is the bright-field mode. In this paper we present experimental data and simulations showing the form of bright-field SCEM images. We show that the depth dependence of the three-dimensional image can be explained in terms of two-dimensional images formed in the detector plane. For a crystalline sample, this so-called probe image is shown to be similar to a conventional diffraction pattern. Experimental results and simulations show how the diffracted probes in this image are elongated in thicker crystals and the use of this elongation to estimate sample thickness is explored. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. High resolution Neutron and Synchrotron Powder Diffraction

    International Nuclear Information System (INIS)

    Hewat, A.W.

    1986-01-01

    The use of high-resolution powder diffraction has grown rapidly in the past years, with the development of Rietveld (1967) methods of data analysis and new high-resolution diffractometers and multidetectors. The number of publications in this area has increased from a handful per year until 1973 to 150 per year in 1984, with a ten-year total of over 1000. These papers cover a wide area of solid state-chemistry, physics and materials science, and have been grouped under 20 subject headings, ranging from catalysts to zeolites, and from battery electrode materials to pre-stressed superconducting wires. In 1985 two new high-resolution diffractometers are being commissioned, one at the SNS laboratory near Oxford, and one at the ILL in Grenoble. In different ways these machines represent perhaps the ultimate that can be achieved with neutrons and will permit refinement of complex structures with about 250 parameters and unit cell volumes of about 2500 Angstrom/sp3/. The new European Synchotron Facility will complement the Grenoble neutron diffractometers, and extend the role of high-resolution powder diffraction to the direct solution of crystal structures, pioneered in Sweden

  10. High resolution CT in diffuse lung disease

    International Nuclear Information System (INIS)

    Webb, W.R.

    1995-01-01

    High resolution CT (computerized tomography) was discussed in detail. The conclusions were HRCT is able to define lung anatomy at the secondary lobular level and define a variety of abnormalities in patients with diffuse lung diseases. Evidence from numerous studies indicates that HRCT can play a major role in the assessment of diffuse infiltrative lung disease and is indicate clinically (95 refs.)

  11. Classification of high resolution satellite images

    OpenAIRE

    Karlsson, Anders

    2003-01-01

    In this thesis the Support Vector Machine (SVM)is applied on classification of high resolution satellite images. Sveral different measures for classification, including texture mesasures, 1st order statistics, and simple contextual information were evaluated. Additionnally, the image was segmented, using an enhanced watershed method, in order to improve the classification accuracy.

  12. High resolution CT in diffuse lung disease

    Energy Technology Data Exchange (ETDEWEB)

    Webb, W R [California Univ., San Francisco, CA (United States). Dept. of Radiology

    1996-12-31

    High resolution CT (computerized tomography) was discussed in detail. The conclusions were HRCT is able to define lung anatomy at the secondary lobular level and define a variety of abnormalities in patients with diffuse lung diseases. Evidence from numerous studies indicates that HRCT can play a major role in the assessment of diffuse infiltrative lung disease and is indicate clinically (95 refs.).

  13. High-resolution clean-sc

    NARCIS (Netherlands)

    Sijtsma, P.; Snellen, M.

    2016-01-01

    In this paper a high-resolution extension of CLEAN-SC is proposed: HR-CLEAN-SC. Where CLEAN-SC uses peak sources in “dirty maps” to define so-called source components, HR-CLEAN-SC takes advantage of the fact that source components can likewise be derived from points at some distance from the peak,

  14. A High-Resolution Stopwatch for Cents

    Science.gov (United States)

    Gingl, Z.; Kopasz, K.

    2011-01-01

    A very low-cost, easy-to-make stopwatch is presented to support various experiments in mechanics. The high-resolution stopwatch is based on two photodetectors connected directly to the microphone input of a sound card. Dedicated free open-source software has been developed and made available to download. The efficiency is demonstrated by a free…

  15. Planning for shallow high resolution seismic surveys

    CSIR Research Space (South Africa)

    Fourie, CJS

    2008-11-01

    Full Text Available of the input wave. This information can be used in conjunction with this spreadsheet to aid the geophysicist in designing shallow high resolution seismic surveys to achieve maximum resolution and penetration. This Excel spreadsheet is available free from...

  16. Low-energy electron transmission through high aspect ratio Al O nanocapillaries

    DEFF Research Database (Denmark)

    Milosavljević, A.R.; Jureta, J.; Víkor, G.

    2009-01-01

    Electron transmission through insulating AlO nanocapillaries of different diameters (40 and 270 nm) and 15 μm length has been investigated for low-energy electrons (2-120 V). The total intensity of transmitted current weakly depends on the incident electron energy and tilt angle defined with resp......Electron transmission through insulating AlO nanocapillaries of different diameters (40 and 270 nm) and 15 μm length has been investigated for low-energy electrons (2-120 V). The total intensity of transmitted current weakly depends on the incident electron energy and tilt angle defined...

  17. The role of electron irradiation history in liquid cell transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Moser, Trevor H.; Mehta, Hardeep S.; Park, Chiwoo; Kelly, Ryan T.; Shokuhfar, Tolou; Evans, James E.

    2018-04-20

    In situ liquid cell transmission electron microscopy (LC-TEM) allows dynamic nanoscale characterization of systems in a hydrated state. Although powerful, this technique remains impaired by issues of repeatability that limit experimental fidelity and hinder the identification and control of some variables underlying observed dynamics. We detail new LC- TEM devices that improve experimental reproducibility by expanding available imaging area and providing a platform for investigating electron flux history on the sample. Irradiation history is an important factor influencing LC-TEM results that has, to this point, been largely qualitatively and not quantitatively described. We use these devices to highlight the role of cumulative electron flux history on samples from both nanoparticle growth and biological imaging experiments and demonstrate capture of time zero, low-dose images on beam-sensitive samples. In particular, the ability to capture pristine images of biological samples, where the acquired image is the first time that the cell experiences significant electron flux, allowed us to determine that nanoparticle movement compared to the cell membrane was a function of cell damage and therefore an artifact rather than visualizing cell dynamics in action. These results highlight just a subset of the new science that is accessible with LC-TEM through the new multiwindow devices with patterned focusing aides.

  18. Path-separated electron interferometry in a scanning transmission electron microscope

    Science.gov (United States)

    Yasin, Fehmi S.; Harvey, Tyler R.; Chess, Jordan J.; Pierce, Jordan S.; McMorran, Benjamin J.

    2018-05-01

    We report a path-separated electron interferometer within a scanning transmission electron microscope. In this setup, we use a nanofabricated grating as an amplitude-division beamsplitter to prepare multiple spatially separated, coherent electron probe beams. We achieve path separations of 30 nm. We pass the  +1 diffraction order probe through amorphous carbon while passing the 0th and  ‑1 orders through vacuum. The probes are then made to interfere via imaging optics, and we observe an interference pattern at the CCD detector with up to 39.7% fringe visibility. We show preliminary experimental results in which the interference pattern was recorded during a 1D scan of the diffracted probes across a test phase object. These results qualitatively agree with a modeled interference predicted by an independent measurement of the specimen thickness. This experimental design can potentially be applied to phase contrast imaging and fundamental physics experiments, such as an exploration of electron wave packet coherence length.

  19. Free radicals. High-resolution spectroscopy and molecular structure

    International Nuclear Information System (INIS)

    Hirota, E.

    1983-01-01

    High-resolution, high-sensitivity spectroscopy using CW laser and microwave sources has been applied to free radicals and transient molecules to establish their existence and to explore their properties in detail. The radicals studied were mainly generated by discharge-induced reactions. A few molecules are used as typical examples to illustrate the results so far obtained. The molecular and electronic structures of free radicals, intramolecular motions of large amplitudes in some labile molecules, and metastable electronic states of carbenes are given special emphasis. The significance of the present spectroscopic results in other related fields such as astronomy and atmospheric chemistry is stressed. 4 figures, 3 tables

  20. Utilizing boron nitride sheets as thin supports for high resolution imaging of nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yimin A; Kirkland, Angus I; Schaeffel, Franziska; Porfyrakis, Kyriakos; Young, Neil P; Briggs, G Andrew D; Warner, Jamie H, E-mail: Jamie.warner@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom)

    2011-05-13

    We demonstrate the use of thin BN sheets as supports for imaging nanocrystals using low voltage (80 kV) aberration-corrected high resolution transmission electron microscopy. This provides an alternative to the previously utilized 2D crystal supports of graphene and graphene oxide. A simple chemical exfoliation method is applied to get few layer boron nitride (BN) sheets with micrometer-sized dimensions. This generic approach of using BN sheets as supports is shown by depositing Mn doped ZnSe nanocrystals directly onto the BN sheets and resolving the atomic structure from both the ZnSe nanocrystals and the BN support. Phase contrast images reveal moire patterns of interference between the beams diffracted by the nanocrystals and the BN substrate that are used to determine the relative orientation of the nanocrystals with respect to the BN sheets and interference lattice planes. Double diffraction is observed and has been analyzed.