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Sample records for technique transmission electron

  1. Nanostructured PLD-grown gadolinia doped ceria: Chemical and structural characterization by transmission electron microscopy techniques

    DEFF Research Database (Denmark)

    Rodrigo, Katarzyna Agnieszka; Wang, Hsiang-Jen; Heiroth, Sebastian

    2011-01-01

    The morphology as well as the spatially resolved elemental and chemical characterization of 10 mol% gadolinia doped ceria (CGO10) structures prepared by pulsed laser deposition (PLD) technique are investigated by scanning transmission electron microscopy accompanied with electron energy loss...... spectroscopy and energy dispersive X-ray spectroscopy. A dense, columnar and structurally inhomogeneous CGO10 film, i.e. exhibiting grain size refinement across the film thickness, is obtained in the deposition process. The cerium M4,5 edges, used to monitor the local electronic structure of the grains...

  2. Nanostructured PLD-grown gadolinia doped ceria: Chemical and structural characterization by transmission electron microscopy techniques

    International Nuclear Information System (INIS)

    Rodrigo, K.; Wang, H.J.; Heiroth, S.; Pryds, N.; Kuhn, L. Theil; Esposito, V.; Linderoth, S.; Schou, J.; Lippert, T.

    2011-01-01

    The morphology as well as the spatially resolved elemental and chemical characterization of 10 mol% gadolinia doped ceria (CGO10) structures prepared by pulsed laser deposition (PLD) technique are investigated by scanning transmission electron microscopy accompanied with electron energy loss spectroscopy and energy dispersive X-ray spectroscopy. A dense, columnar and structurally inhomogeneous CGO10 film, i.e. exhibiting grain size refinement across the film thickness, is obtained in the deposition process. The cerium M 4,5 edges, used to monitor the local electronic structure of the grains, indicate apparent variation of the ceria valence state across and along the film. No element segregation to the grain boundaries is detected. These results are discussed in the context of solid oxide fuel cell applications.

  3. A high-speed area detector for novel imaging techniques in a scanning transmission electron microscope

    International Nuclear Information System (INIS)

    Caswell, T.A.; Ercius, P.; Tate, M.W.; Ercan, A.; Gruner, S.M.; Muller, D.A.

    2009-01-01

    A scanning transmission electron microscope (STEM) produces a convergent beam electron diffraction pattern at each position of a raster scan with a focused electron beam, but recording this information poses major challenges for gathering and storing such large data sets in a timely manner and with sufficient dynamic range. To investigate the crystalline structure of materials, a 16x16 analog pixel array detector (PAD) is used to replace the traditional detectors and retain the diffraction information at every STEM raster position. The PAD, unlike a charge-coupled device (CCD) or photomultiplier tube (PMT), directly images 120-200 keV electrons with relatively little radiation damage, exhibits no afterglow and limits crosstalk between adjacent pixels. Traditional STEM imaging modes can still be performed by the PAD with a 1.1 kHz frame rate, which allows post-acquisition control over imaging conditions and enables novel imaging techniques based on the retained crystalline information. Techniques for rapid, semi-automatic crystal grain segmentation with sub-nanometer resolution are described using cross-correlation, sub-region integration, and other post-processing methods.

  4. Determining oxygen relaxations at an interface: A comparative study between transmission electron microscopy techniques.

    Science.gov (United States)

    Gauquelin, N; van den Bos, K H W; Béché, A; Krause, F F; Lobato, I; Lazar, S; Rosenauer, A; Van Aert, S; Verbeeck, J

    2017-10-01

    Nowadays, aberration corrected transmission electron microscopy (TEM) is a popular method to characterise nanomaterials at the atomic scale. Here, atomically resolved images of nanomaterials are acquired, where the contrast depends on the illumination, imaging and detector conditions of the microscope. Visualization of light elements is possible when using low angle annular dark field (LAADF) STEM, annular bright field (ABF) STEM, integrated differential phase contrast (iDPC) STEM, negative spherical aberration imaging (NCSI) and imaging STEM (ISTEM). In this work, images of a NdGaO 3 -La 0.67 Sr 0.33 MnO 3 (NGO-LSMO) interface are quantitatively evaluated by using statistical parameter estimation theory. For imaging light elements, all techniques are providing reliable results, while the techniques based on interference contrast, NCSI and ISTEM, are less robust in terms of accuracy for extracting heavy column locations. In term of precision, sample drift and scan distortions mainly limits the STEM based techniques as compared to NCSI. Post processing techniques can, however, partially compensate for this. In order to provide an outlook to the future, simulated images of NGO, in which the unavoidable presence of Poisson noise is taken into account, are used to determine the ultimate precision. In this future counting noise limited scenario, NCSI and ISTEM imaging will provide more precise values as compared to the other techniques, which can be related to the mechanisms behind the image recording. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Technique for the Characterization of Phospholipid Microbubbles Coatings by Transmission Electron Microscopy.

    Science.gov (United States)

    Owen, Joshua; Stride, Eleanor

    2015-12-01

    Gas microbubbles stabilized by a surfactant or polymer coating are of considerable clinical interest because of their imaging and drug delivery potential under ultrasound exposure. The utility of microbubbles for a given application is intrinsically linked to their structure and stability. These in turn are highly sensitive to coating composition and fabrication techniques. Various methods including fluorescence and atomic force microscopy have been applied to characterize microbubble properties, but direct observation of coating structure at the nanoscale still poses a considerable challenge. Here we describe a transmission electron microscopy (TEM) technique to observe the surface of microbubbles. Images from a series of phospholipid-coated microbubble systems, including those decorated with nanoparticles, are presented. They indicate that the technique enables visualization of the coating structure, in particular lipid discontinuities and nanoparticle distribution. This information can be used to better understand how microbubble surface structure relates to formulation and/or processing technique and ultimately to functionality. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  6. Scanning transmission electron microscope

    NARCIS (Netherlands)

    Kruit, P.

    2006-01-01

    The invention relates to a scanning transmission electron microscope comprising an electron source, an electron accelerator and deflection means for directing electrons emitted by the electron source at an object to be examined, and in addition a detector for detecting electrons coming from the

  7. Transmission Electron Microscopy as Key Technique for the Characterization of Telocytes.

    Science.gov (United States)

    Cantarero, Irene; Luesma, Maria Jose; Alvarez-Dotu, Jose Miguel; Muñoz, Eduardo; Junquera, Concepcion

    2016-01-01

    It was 50 years ago when the details of cellular structure were first observed with an electron microscope (EM). Today, transmission electron microscopy (TEM) still provides the highest resolution detail of cellular ultrastructure. The existence of telocytes (TCs) has been described by Hinescu and Popescu in 2005 and up to now, many studies have been done in different tissues. EM has been fundamental in identification and recognition of TC and relationship between TC and stem cells (SCs) in recent years. We present a review on the importance of TEM to provide major advances in the knowledge of the biology of these cells.

  8. 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.

  9. Technique for preparation of transmission electron microscope specimens from wire samples of Al and Al-Al2O3 alloys

    DEFF Research Database (Denmark)

    Lindbo, Jørgen

    1966-01-01

    A technique for thinning 1 mm wire samples of aluminium and aluminium-alumina alloys for transmission electron microscopy is described. The essential feature of the technique, which involves spark machining and electropolishing in a polytetrafluoroethylene holder followed by chemical polishing, i...

  10. 3D printed electromagnetic transmission and electronic structures fabricated on a single platform using advanced process integration techniques

    Science.gov (United States)

    Deffenbaugh, Paul Issac

    3D printing has garnered immense attention from many fields including in-office rapid prototyping of mechanical parts, outer-space satellite replication, garage functional firearm manufacture, and NASA rocket engine component fabrication. 3D printing allows increased design flexibility in the fabrication of electronics, microwave circuits and wireless antennas and has reached a level of maturity which allows functional parts to be printed. Much more work is necessary in order to perfect the processes of 3D printed electronics especially in the area of automation. Chapter 1 shows several finished prototypes of 3D printed electronics as well as newly developed techniques in fabrication. Little is known about the RF and microwave properties and applications of the standard materials which have been developed for 3D printing. Measurement of a wide variety of materials over a broad spectrum of frequencies up to 10 GHz using a variety of well-established measurement methods is performed throughout chapter 2. Several types of high frequency RF transmission lines are fabricated and valuable model-matched data is gathered and provided in chapter 3 for future designers' use. Of particular note is a fully 3D printed stripline which was automatically fabricated in one process on one machine. Some core advantages of 3D printing RF/microwave components include rapid manufacturing of complex, dimensionally sensitive circuits (such as antennas and filters which are often iteratively tuned) and the ability to create new devices that cannot be made using standard fabrication techniques. Chapter 4 describes an exemplary fully 3D printed curved inverted-F antenna.

  11. Analytics on Transmission Electron Microscopy

    International Nuclear Information System (INIS)

    Keum, Dong Hwa; Kim, Geung Ho; Lee, Hwak Ju and others

    1996-06-01

    This book gives descriptions of transmission electron microscopy, which deals with electron microscopy and materials science, history of electron microscopy, application of analytics on transmission electron microscopy, machine requirement of transmission electron microscopy like electron gun and TEM image and function, crystal diffraction, electron diffraction, Kikuchi's diffraction figure, analysis of diffraction figure, contrast of TEM image like absorption contrast, and phase contrast, Fresnel's diffraction and TEM contrast, thickness fringe, column approximation, analysis of diffraction contrast, image simulation, and electron energy loss spectrometry.

  12. Low voltage transmission electron microscopy of graphene.

    Science.gov (United States)

    Bachmatiuk, Alicja; Zhao, Jiong; Gorantla, Sandeep Madhukar; Martinez, Ignacio Guillermo Gonzalez; Wiedermann, Jerzy; Lee, Changgu; Eckert, Juergen; Rummeli, Mark Hermann

    2015-02-04

    The initial isolation of graphene in 2004 spawned massive interest in this two-dimensional pure sp(2) carbon structure due to its incredible electrical, optical, mechanical, and thermal effects. This in turn led to the rapid development of various characterization tools for graphene. Examples include Raman spectroscopy and scanning tunneling microscopy. However, the one tool with the greatest prowess for characterizing and studying graphene is the transmission electron microscope. State-of-the-art (scanning) transmission electron microscopes enable one to image graphene with atomic resolution, and also to conduct various other characterizations simultaneously. The advent of aberration correctors was timely in that it allowed transmission electron microscopes to operate with reduced acceleration voltages, so that damage to graphene is avoided while still providing atomic resolution. In this comprehensive review, a brief introduction is provided to the technical aspects of transmission electron microscopes relevant to graphene. The reader is then introduced to different specimen preparation techniques for graphene. The different characterization approaches in both transmission electron microscopy and scanning transmission electron microscopy are then discussed, along with the different aspects of electron diffraction and electron energy loss spectroscopy. The use of graphene for other electron microscopy approaches such as in-situ investigations is also presented. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Transmission Electron Microscopy Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Performs basic and applied research in areas of marine geosciences, geophysics, physics, and microbiology using microanalytical techniques.DESCRIPTION: The...

  14. In Situ Transmission Electron Microscopy for Electronics

    OpenAIRE

    Arita, Masashi; Hamada, Kouichi; Takahashi, Yasuo; Sueoka, Kazuhisa; Shibayama, Tamaki

    2015-01-01

    Electronic devices are strongly influenced by their microstructures. In situ transmission electron microscopy (in situ TEM) with capability to measure electrical properties is an effective method to dynamically correlate electric properties with microstructures. We have developed tools and in situ TEM experimental procedures for measuring electronic devices, including TEM sample holders and sample preparation methods. The method was used to study metallic nanowire by electromigration, magn...

  15. Applications of orientation mapping by scanning and transmission electron microscopy

    DEFF Research Database (Denmark)

    Juul Jensen, D.

    1997-01-01

    The potentials of orientation mapping techniques (in the following referred to as OIM) for studies of thermomechanical processes are analysed. Both transmission electron microscopy (TEM) and scanning electron microscopy (SEM) based OIM techniques are considered. Among the thermomechanical processes...

  16. Transmission electron microscopy characterization of nanomaterials

    CERN Document Server

    2014-01-01

    Third volume of a 40volume series on nanoscience and nanotechnology, edited by the renowned scientist Challa S.S.R. Kumar. This handbook gives a comprehensive overview about Transmission electron microscopy characterization of nanomaterials. Modern applications and state-of-the-art techniques are covered and make this volume an essential reading for research scientists in academia and industry.

  17. Proximity Scanning Transmission Electron Microscopy/Spectroscopy

    OpenAIRE

    Hwang, Ing-Shouh

    2016-01-01

    Here a new microscopic method is proposed to image and characterize very thin samples like few-layer materials, organic molecules, and nanostructures with nanometer or sub-nanometer resolution using electron beams of energies lower than 20 eV. The microscopic technique achieves high resolution through the proximity (or near-field) effect, as in scanning tunneling microscopy (STM), while it also allows detection of transmitted electrons for imaging and spectroscopy, as in scanning transmission...

  18. 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

  19. 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

  20. 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.

  1. Advanced transmission electron microscopy on nanostructured magnetic materials

    OpenAIRE

    Campanini, Marco

    2015-01-01

    This doctoral work is focused on the study of nanostructured magnetic materials by advanced transmission electron microscopy (TEM) techniques, with emphasis on Ni2MnGa shape memory alloy thin films and magnetite nanoparticles for biomedical applications. The combination of high-resolution transmission electron microscopy and electron diffraction to characterize morphology and crystalline structure, with Lorentz microscopy and Electron Holography, permits to achieve a deep insight in the s...

  2. 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...

  3. Mapping unoccupied electronic states of freestanding graphene by angle-resolved low-energy electron transmission

    OpenAIRE

    Wicki Flavio; Longchamp Jean-Nicolas; Latychevskaia Tatiana; Escher Conrad; Fink Hans-Werner

    2016-01-01

    We report angle-resolved electron transmission measurements through freestanding graphene sheets in the energy range of 18 to 30 eV above the Fermi level. The measurements are carried out in a low-energy electron point source microscope, which allows simultaneously probing the transmission for a large angular range. The characteristics of low-energy electron transmission through graphene depend on its electronic structure above the vacuum level. The experimental technique described here allow...

  4. Electronic waste recycling techniques

    CERN Document Server

    Bernardes, Andréa

    2015-01-01

    This book presents an overview of the characterization of electronic waste. In addition, processing techniques for the recovery of metals, polymers and ceramics are described. This book serves as a source of information and as an educational technical reference for practicing scientists and engineers, as well as for students.

  5. Electronic Packaging Techniques

    Science.gov (United States)

    1979-01-01

    A characteristic of aerospace system design is that equipment size and weight must always be kept to a minimum, even in small components such as electronic packages. The dictates of spacecraft design have spawned a number of high-density packaging techniques, among them methods of connecting circuits in printed wiring boards by processes called stitchbond welding and parallel gap welding. These processes help designers compress more components into less space; they also afford weight savings and lower production costs.

  6. Cathodoluminescence in the scanning transmission electron microscope.

    Science.gov (United States)

    Kociak, M; Zagonel, L F

    2017-05-01

    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. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. 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.

  8. 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.

  9. 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...

  10. In situ nanoindentation in a transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Minor, Andrew M. [Univ. of California, Berkeley, CA (United States)

    2002-01-01

    This dissertation presents the development of the novel mechanical testing technique of in situ nanoindentation in a transmission electron microscope (TEM). This technique makes it possible to simultaneously observe and quantify the mechanical behavior of nano-scale volumes of solids.

  11. 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...

  12. 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)

  13. Cellular imaging electron tomography and related techniques

    CERN Document Server

    2018-01-01

    This book highlights important techniques for cellular imaging and covers the basics and applications of electron tomography and related techniques. In addition, it considers practical aspects and broadens the technological focus by incorporating techniques that are only now becoming accessible (e.g. block face imaging).  The first part of the book describes the electron microscopy 3D technique available to scientists around the world, allowing them to characterize organelles, cells and tissues. The major emphasis is on new technologies like scanning transmission electron microscopy (STEM) tomography, though the book also reviews some of the more proven technologies like electron tomography. In turn, the second part is dedicated to the reconstruction of data sets, signal improvement and interpretation.

  14. Measurement of total electron content of midlatitude ionosphere and protonosphere via Faraday rotation and group relay techniques using transmission from geostationary satellites ATS-3 and ATS-6

    Science.gov (United States)

    Paul, M. P.

    1982-01-01

    Measurement of integrated columnar electron content and total electron content for the local ionosphere and the overlying protonosphere via Faraday rotation and group delay techniques has proven very useful. A field station was established having the geographic location of 31.5 deg N latitude and 91.06 deg W longitude to accomplish these objectives. A polarimeter receiving system was set up in the beginning to measure the Faraday rotation of 137.35 MHz radio signal from geostationary satellite ATS 3 to yield the integrated columnar electron content of the local ionosphere. The measurement was continued regularly, and the analysis of the data thus collected provided a synopsis of the statistical variation of the ionosphere along with the transient variations that occurred during the periods of geomagnetic and other disturbances.

  15. 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.

  16. Oxidation mechanism of nickel particles studied in an environmental transmission electron microscope

    DEFF Research Database (Denmark)

    Jeangros, Q.; Hansen, Thomas Willum; Wagner, Jakob Birkedal

    2014-01-01

    The oxidation of nickel particles was studied in situ in an environmental transmission electron microscope in 3.2 mbar of O2 between ambient temperature and 600°C. Several different transmission electron microscopy imaging techniques, electron diffraction and electron energy-loss spectroscopy were...

  17. 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 ...

  18. Study by transmission electron microcospy of activated saponite

    OpenAIRE

    Suárez Barrios, M.; Romero, E.; Santiago, C. de; Martín Pozas, J. M.

    1999-01-01

    This work studies the modifications undergone by the Creen Clays Saponite in the Tagus Basin subjected to activation treatments, and stresses the influence of the development of the electronic microscopy technique for studying these materials. Acid treatment with HCI and pillaring treatment with All3 were performed. Characterization of the samples was carried out by DRX, chemical analysis of major elements and Transmission Electronic Microscopy. Add treament causes the delamination and fragme...

  19. 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.

  20. 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...

  1. 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...... 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...... in the oxic zone. Oxygen seems to be the major electron acceptor in the coupled system, and more than 40% of the oxygen consumption can be driven by long distance electron transmission. The major e-donor is sulfide, which is oxidized to sulfate, and iron sulphides are the major sources for sulfide...

  2. Transmission techniques for 4G systems

    CERN Document Server

    Da Silva, Mario Marques

    2012-01-01

    Fourth Generation (4G) wireless communication systems support current and emergent multimedia services such as mobile TV, social networks and gaming, high-definition TV, video teleconferencing, and messaging services. These systems feature the All-over-IP concept and boast improved quality of service. Several important R&D activities are currently under way in the field of wireless communications for 4G systems, but the coverage is widespread in the literature. Transmission Techniques for 4G Systems presents a compilation of the latest developments in the field of wireless communications for 4

  3. 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

  4. 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...

  5. 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.

  6. 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.

  7. 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.)

  8. Quantitative characterization of electron detectors for transmission electron microscopy.

    Science.gov (United States)

    Ruskin, Rachel S; Yu, Zhiheng; Grigorieff, Nikolaus

    2013-12-01

    A new generation of direct electron detectors for transmission electron microscopy (TEM) promises significant improvement over previous detectors in terms of their modulation transfer function (MTF) and detective quantum efficiency (DQE). However, the performance of these new detectors needs to be carefully monitored in order to optimize imaging conditions and check for degradation over time. We have developed an easy-to-use software tool, FindDQE, to measure MTF and DQE of electron detectors using images of a microscope's built-in beam stop. Using this software, we have determined the DQE curves of four direct electron detectors currently available: the Gatan K2 Summit, the FEI Falcon I and II, and the Direct Electron DE-12, under a variety of total dose and dose rate conditions. We have additionally measured the curves for the Gatan US4000 and TVIPS TemCam-F416 scintillator-based cameras. We compare the results from our new method with published curves. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Simplifying Electron Beam Channeling in Scanning Transmission Electron Microscopy (STEM).

    Science.gov (United States)

    Wu, Ryan J; Mittal, Anudha; Odlyzko, Michael L; Mkhoyan, K Andre

    2017-08-01

    Sub-angstrom scanning transmission electron microscopy (STEM) allows quantitative column-by-column analysis of crystalline specimens via annular dark-field images. The intensity of electrons scattered from a particular location in an atomic column depends on the intensity of the electron probe at that location. Electron beam channeling causes oscillations in the STEM probe intensity during specimen propagation, which leads to differences in the beam intensity incident at different depths. Understanding the parameters that control this complex behavior is critical for interpreting experimental STEM results. In this work, theoretical analysis of the STEM probe intensity reveals that intensity oscillations during specimen propagation are regulated by changes in the beam's angular distribution. Three distinct regimes of channeling behavior are observed: the high-atomic-number (Z) regime, in which atomic scattering leads to significant angular redistribution of the beam; the low-Z regime, in which the probe's initial angular distribution controls intensity oscillations; and the intermediate-Z regime, in which the behavior is mixed. These contrasting regimes are shown to exist for a wide range of probe parameters. These results provide a new understanding of the occurrence and consequences of channeling phenomena and conditions under which their influence is strengthened or weakened by characteristics of the electron probe and sample.

  10. Effective cellulose nanocrystal imaging using transmission electron microscopy.

    Science.gov (United States)

    Stinson-Bagby, Kelly L; Roberts, Rose; Foster, E Johan

    2018-04-15

    Characterization of cellulose nanocrystals (CNCs) is often complex and tedious. With their increased use for biological materials, polymer reinforcing agents, and other applications, better characterization methods of CNCs are needed to ensure product quality. However, because of their small size, hydrogen bonding, and low electron density, individual CNCs are difficult to image with high resolution and magnification using electron microscopy. Methods to help counter these challenges include staining for increased contrast and techniques to increase dispersion. This work tested several stains, dispersing agents, and sample supports to find a consistent method of individualizing CNCs and providing good contrast for imaging in transmission electron microscopy (TEM). The most consistent method found uses a low concentration of CNCs, bovine serum albumin as a dispersing agent, and Nanovan ® as the contrasting stain on a silicon monoxide-coated Formvar TEM grid. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. 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.

  12. 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.

  13. Charging of carbon thin films in scanning and phase-plate transmission electron microscopy

    DEFF Research Database (Denmark)

    Hettler, Simon; Kano, Emi; Dries, Manuel

    2018-01-01

    A systematic study on charging of carbon thin films under intense electron-beam irradiation was performed in a transmission electron microscope to identify the underlying physics for the functionality of hole-free phase plates. Thin amorphous carbon films fabricated by different deposition...... as simulations of the electrostatic potential distribution. The described ESD-based model explains previous experimental findings and is of general interest to any phase-related technique in a transmission electron microscope....

  14. 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

  15. 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)

  16. Object oriented database and electronic notebook for transmission electron microscopy.

    Science.gov (United States)

    Ludtke, Steven J; Nason, Laurie; Tu, Haili; Peng, Liwei; Chiu, Wah

    2003-12-01

    As high-resolution biological transmission electron microscopy (TEM) has increased in popularity over recent years, the volume of data and number of projects underway has risen dramatically. A robust tool for effective data management is essential to efficiently process large data sets and extract maximum information from the available data. We present the Electron Microscopy Electronic Notebook (EMEN), a portable, object-oriented, web-based tool for TEM data archival and project management. EMEN has several unique features. First, the database is logically organized and annotated so multiple collaborators at different geographical locations can easily access and interpret the data without assistance. Second, the database was designed to provide flexibility to the user, so it can be used much as a lab notebook would be, while maintaining a structure suitable for data mining and direct interaction with data-processing software. Finally, as an object-oriented database, the database structure is dynamic and can be easily extended to incorporate information not defined in the original database specification.

  17. Transmission techniques for emergent multicast and broadcast systems

    CERN Document Server

    da Silva, Mario Marques; Dinis, Rui; Souto, Nuno; Silva, Joao Carlos

    2010-01-01

    Describing efficient transmission schemes for broadband wireless systems, Transmission Techniques for Emergent Multicast and Broadcast Systems examines advances in transmission techniques and receiver designs capable of supporting the emergent wireless needs for multimedia broadcast and multicast service (MBMS) requirements. It summarizes the research and development taking place in wireless communications for multimedia MBMS and addresses the means to improved spectral efficiency to allow for increased user bit rate, as well as increased capacity of the digital cellular radio network.The text

  18. 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...

  19. 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.

  20. 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....

  1. Complex band structure and electronic transmission eigenchannels

    DEFF Research Database (Denmark)

    Jensen, Anders; Strange, Mikkel; Smidstrup, Soren

    2017-01-01

    molecular junctions. The molecular junctions show that both the length dependence of the total transmission and the individual transmission eigenvalues can be, almost always, found through the complex band structure. The complex band structure of the semi-conducting material, however, does not predict...

  2. 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

  3. Insights into complexation of dissolved organic matter and Al(III) and nanominerals formation in soils under contrasting fertilizations using two-dimensional correlation spectroscopy and high resolution-transmission electron microscopy techniques.

    Science.gov (United States)

    Wen, Yongli; Li, Huan; Xiao, Jian; Wang, Chang; Shen, Qirong; Ran, Wei; He, Xinhua; Zhou, Quansuo; Yu, Guanghui

    2014-09-01

    Understanding the organomineral associations in soils is of great importance. Using two-dimensional correlation spectroscopy (2DCOS) and high resolution-transmission electron microscopy (HRTEM) techniques, this study compared the binding characteristics of organic ligands to Al(III) in dissolved organic matter (DOM) from soils under short-term (3-years) and long-term (22-years) fertilizations. Three fertilization treatments were examined: (i) no fertilization (Control), (ii) chemical nitrogen, phosphorus and potassium (NPK), and (iii) NPK plus swine manure (NPKM). Soil spectra detected by the 2DCOS Fourier transform infrared (FTIR) spectroscopy showed that fertilization modified the binding characteristics of organic ligands to Al(III) in soil DOM at both short- and long- term location sites. The CH deformations in aliphatic groups played an important role in binding to Al(III) but with minor differences among the Control, NPK and NPKM at the short-term site. While at the long-term site both C-O stretching of polysaccharides or polysaccharide-like substances and aliphatic O-H were bound to Al(III) under the Control, whereas only aliphatic O-H, and only polysaccharides and silicates, were bound to Al(III) under NPK and NPKM, respectively. Images from HRTEM demonstrated that crystalline nanominerals, composed of Fe and O, were predominant in soil DOM under NPK, while amorphous nanominerals, predominant in Al, Si, and O, were dominant in soil DOM under Control and NPKM. In conclusion, fertilization strategies, especially under long-term, could affect the binding of organic ligands to Al(III) in soil DOM, which resulted in alterations in the turnover, reactivity, and bioavailability of soil organic matter. Our results demonstrated that the FTIR-2DCOS combined with HRTEM techniques could enhance our understanding in the binding characteristics of DOM to Al(III) and the resulted nanominerals in soils. Copyright © 2014 Elsevier Ltd. All rights reserved.

  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. 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.

  6. Image Resolution in Scanning Transmission Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pennycook, S. J.; Lupini, A.R.

    2008-06-26

    Digital images captured with electron microscopes are corrupted by two fundamental effects: shot noise resulting from electron counting statistics and blur resulting from the nonzero width of the focused electron beam. The generic problem of computationally undoing these effects is called image reconstruction and for decades has proved to be one of the most challenging and important problems in imaging science. This proposal concerned the application of the Pixon method, the highest-performance image-reconstruction algorithm yet devised, to the enhancement of images obtained from the highest-resolution electron microscopes in the world, now in operation at Oak Ridge National Laboratory.

  7. 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.)

  8. Transmission electron microscopy characterisation of 0-D nanomaterials

    Science.gov (United States)

    Turner, Stuart Matthew

    When materials are scaled down to the nanometre level, a change in physical behaviour is frequently observed. In so-called 0-D nanomaterials (nanoparticles), these unique nanoscale properties are most abundant and are usually linked to either a change in (electronic) structure of the material or to the dominating influence of the particle surface at the nanometre scale. In this doctoral work the nanoscale properties of several nanoparticle systems have been studied using advanced transmission electron microscopy (TEM). Every material that was studied required for its solution a unique approach and a host of transmission electron microscopy techniques. The title of this doctoral work can be freely translated as "retrieving quantitatively the maximal and most accurate chemical, structural and morphological information from nanoparticles by advanced transmission electron microscopy, to uncover and explain their unique properties". Chapter 1 gives a brief general introduction to the world of nanomaterials and nanotechnology in general and more specifically to 0-D nanomaterials (nanoparticles). The unique properties and potential applications of these materials are described. The production of 0-D nanomaterials is not covered in this chapter, as this is an extremely broad field to cover in only a few pages. Instead, the production method for each of the materials is left to the detailed chapters that follow. In Chapter 2 the main transmission electron microscopy techniques used to characterise the materials in the further chapters are described together with the microscopes used to perform these techniques and their parameters of operation. Again, the sample-specific setups are listed in the detailed chapters that follow. Chapter 3 covers all work carried out on luminescent detonation nanodiamond powder for drug delivery and bio-medical imaging applications. Specific attention is paid to the morphology, surface chemistry and nitrogen incorporation of detonation

  9. 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...

  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. 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.

  12. A Comparative Analysis of Transmission Control Protocol Improvement Techniques over Space-Based Transmission Media

    National Research Council Canada - National Science Library

    Lawson, Joseph M

    2006-01-01

    ... justification for the implementation of a given enhancement technique. The research questions were answered through model and simulation of a satellite transmission system via a Linux-based network topology...

  13. In situ and operando transmission electron microscopy of catalytic materials

    DEFF Research Database (Denmark)

    Crozier, Peter A.; Hansen, Thomas Willum

    2015-01-01

    Catalytic nanomaterials play a major role in chemical conversions and energy transformations. Understanding how materials control and regulate surface reactions is a major objective for fundamental research on heterogeneous catalysts. In situ environmental transmission electron microscopy (ETEM...

  14. 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.

  15. 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

  16. Recent techniques used in transmission line protection: A review ...

    African Journals Online (AJOL)

    include almost all the techniques and philosophies of transmission line protection reported in the literature up to October 2010. The focus of this article is on the most recent techniques, like artificial neural network, fuzzy logic, fuzzy-neuro, fuzzy logicwavelet based and phasor measurement unit-based concepts as well as ...

  17. Digital processing optical transmission and coherent receiving techniques

    CERN Document Server

    Binh, Le Nguyen

    2013-01-01

    With coherent mixing in the optical domain and processing in the digital domain, advanced receiving techniques employing ultra-high speed sampling rates have progressed tremendously over the last few years. These advances have brought coherent reception systems for lightwave-carried information to the next stage, resulting in ultra-high capacity global internetworking. Digital Processing: Optical Transmission and Coherent Receiving Techniques describes modern coherent receiving techniques for optical transmission and aspects of modern digital optical communications in the most basic lines. The

  18. 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.

  19. Microstructural studies of dental amalgams using analytical transmission electron microscopy

    Science.gov (United States)

    Hooghan, Tejpal Kaur

    Dental amalgams have been used for centuries as major restorative materials for decaying teeth. Amalgams are prepared by mixing alloy particles which contain Ag, Sn, and Cu as the major constituent elements with liquid Hg. The study of microstructure is essential in understanding the setting reactions and improving the properties of amalgams. Until the work reported in this dissertation, optical microscopy (OM), scanning electron microscopy (SEM), and x-ray diffractometry (XRD) were used commonly to analyze amalgam microstructures. No previous systematic transmission electron microscopy (TEM) study has been performed due to sample preparation difficulties and composite structure of dental amalgams. The goal of this research was to carry out detailed microstructural and compositional studies of dental amalgams. This was accomplished using the enhanced spatial resolution of the TEM and its associated microanalytical techniques, namely, scanning transmission electron microscopy (STEM), x-ray energy dispersive spectroscopy (XEDS) and micro-microdiffraction (mumuD). A new method was developed for thinning amalgam samples to electron transparency using the "wedge technique." Velvalloy, a low-Cu amalgam, and Tytin, a high-Cu amalgam, were the two amalgams characterized. Velvalloy is composed of a Agsb2Hgsb3\\ (gammasb1)/HgSnsb{7-9}\\ (gammasb2) matrix surrounding unreacted Agsb3Sn (gamma) particles. In addition, hitherto uncharacterized reaction layers between Agsb3Sn(gamma)/Agsb2Hgsb3\\ (gammasb2)\\ and\\ Agsb2Hgsb3\\ (gammasb1)/HgSnsb{7-9}\\ (gammasb2) were observed and analyzed. An Ag-Hg-Sn (betasb1) phase was clearly identified for the first time. In Tytin, the matrix consists of Agsb2Hgsb3\\ (gammasb1) grains. Fine precipitates of Cusb6Snsb5\\ (etasp') are embedded inside the gammasb1 and at the grain boundaries. These precipitates are responsible for the improved creep resistance of Tytin compared to Velvalloy. The additional Cu has completely eliminated the gammasb

  20. 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

  1. Investigation of ceramic devices by analytical electron microscopy techniques

    International Nuclear Information System (INIS)

    Shiojiri, M.; Saijo, H.; Isshiki, T.; Kawasaki, M.; Yoshioka, T.; Sato, S.; Nomura, T.

    1999-01-01

    Ceramics are widely used as capacitors and varistors. Their electrical properties depend on the structure, which is deeply influenced not only by the composition of raw materials and additives but also by heating treatments in the production process. This paper reviews our investigations of SrTiO 3 ceramic devices, which have been performed using various microscopy techniques such as high-resolution transmission electron microscopy (HRTEM), cathodoluminescence scanning electron microscopy (CLSEM), field emission SEM (FE-SEM), energy dispersive X-ray spectroscopy (EDS), electron energy-loss spectroscopy (EELS) and high angle annular dark field (HAADF) imaging method in a FE-(scanning) transmission electron microscope(FE-(S)TEM). (author)

  2. Environmental testing techniques for electronics and materials

    CERN Document Server

    Dummer, Geoffrey W A; Fry, D W; Higinbotham, W

    2013-01-01

    Environmental Testing Techniques for Electronics and Materials reviews environmental testing techniques for evaluating the performance of electronic equipment, components, and materials. Environmental test planning, test methods, and instrumentation are described, along with the general environmental conditions under which equipment must operate. This book is comprised of 15 chapters and begins by explaining why environmental testing is necessary and describing the environment in which electronics must operate. The next chapter considers how an environmental test plan is designed; the methods

  3. 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

  4. Scanning transmission electron microscopy imaging and analysis

    CERN Document Server

    Pennycook, Stephen J

    2011-01-01

    Provides the first comprehensive treatment of the physics and applications of this mainstream technique for imaging and analysis at the atomic level Presents applications of STEM in condensed matter physics, materials science, catalysis, and nanoscience Suitable for graduate students learning microscopy, researchers wishing to utilize STEM, as well as for specialists in other areas of microscopy Edited and written by leading researchers and practitioners

  5. 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...

  6. Transmission electron microscopy physics of image formation and microanalysis

    CERN Document Server

    Reimer, Ludwig

    1989-01-01

    The aim of this book is to present 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 determination and imaging of lattice defects X-ray microanalysis and energy-loss spectroscopy are treated as analytical methods The second edition includes discussion of recent progress, especially in the areas of energy-loss spectroscopy, crystal-lattice imaging and reflection electron microscopy

  7. Low Voltage Transmission Electron Microscopy in Cell Biology.

    Science.gov (United States)

    Bendayan, Moise; Paransky, Eugene

    2015-07-01

    Low voltage transmission electron microscopy (LVTEM) was employed to examine biological tissues with accelerating voltages as low as 5kV. Tissue preparation was modified to take advantage of the low-voltage techniques. Treatments with heavy metals, such as post-fixation with osmium tetroxide, on block and counterstaining were omitted. Sections (40nm) were thinner than usual and generated highly contrasted images. General appearance of the cells remains similar to that of conventional TEM. New features were however revealed. The matrix of the pancreatic granules displays heterogeneity with partitions that may correspond to the inner-segregation of their secretory proteins. Mitochondria revealed the presence of the ATP synthase granules along their cristea. The nuclear dense chromatin displayed a honeycomb organization while distinct beads, nucleosomes, aligned along thin threads were seen in the dispersed chromatin. Nuclear pore protein complexes revealed their globular nature. The intercalated disks in cardiac muscle displayed their fine structural organization. These features correlate well with data described or predicted by cell and molecular biology. These new aspects are not revealed when thicker and conventionally osmicated tissue sections were examined by LVTEM, indicating that major masking effects are associated with standard TEM techniques. Immunogold was adapted to LVTEM further enhancing its potential in cell biology. Copyright © 2015 Elsevier GmbH. All rights reserved.

  8. Transmission electron imaging in the Delft multibeam scanning electron microscope 1

    NARCIS (Netherlands)

    Ren, Y.; Kruit, P.

    2016-01-01

    Our group is developing a multibeam scanning electron microscope (SEM) with 196 beams in order to increase the throughput of SEM. Three imaging systems using, respectively, transmission electron detection, secondary electron detection, and backscatter electron detection are designed in order to

  9. Integrated Transmission Electron and Single-Molecule Fluorescence Microscopy Correlates Reactivity with Ultrastructure in a Single Catalyst Particle

    NARCIS (Netherlands)

    Hendriks, Frank C.|info:eu-repo/dai/nl/412642697; Mohammadian, Sajjad|info:eu-repo/dai/nl/374721327; Ristanovic, Zoran|info:eu-repo/dai/nl/328233005; Kalirai, Samanbir; Meirer, Florian; Vogt, Eelco T. C.|info:eu-repo/dai/nl/073717398; Bruijnincx, Pieter C. A.|info:eu-repo/dai/nl/33799529X; Gerritsen, Hans|info:eu-repo/dai/nl/071548777; Weckhuysen, Bert M.|info:eu-repo/dai/nl/285484397

    2018-01-01

    Establishing structure–activity relationships in complex, hierarchically structured nanomaterials, such as fluid catalytic cracking (FCC) catalysts, requires characterization with complementary, correlated analysis techniques. An integrated setup has been developed to perform transmission electron

  10. Image simulations of kinked vortices for transmission electron microscopy

    DEFF Research Database (Denmark)

    Beleggia, Marco; Pozzi, G.; Tonomura, A.

    2010-01-01

    We present an improved model of kinked vortices in high-Tc superconductors suitable for the interpretation of Fresnel or holographic observations carried out with a transmission electron microscope. A kinked vortex is composed of two displaced half-vortices, perpendicular to the film plane...... observations of high-Tc superconducting films, where the Fresnel contrast associated with some vortices showed a dumbbell like appearance. Here, we show that under suitable conditions the JV segment may reveal itself in Fresnel imaging or holographic phase mapping in a transmission electron microscope....

  11. 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....

  12. Microdomain fluctuations in lead scandium tantalate (PST) observed by high resolution transmission electron microscopy

    International Nuclear Information System (INIS)

    Bursill, L.A.; Peng, Julin.

    1992-01-01

    The value of the high-resolution transmission electron microscopy (HRTEM) and dark-field imaging techniques for obtaining nanocrystalline structural information is demonstrated for lead scandium tantalite (PST). Chemical domain textures, polar domain fluctuations and HRTEM images of disordered and ordered PTS are discussed. 5 refs., 5 figs

  13. Environmental Transmission Electron Microscopy in an Aberration-Corrected Environment

    DEFF Research Database (Denmark)

    Hansen, Thomas W.; Wagner, Jakob B.

    2012-01-01

    The increasing use of environmental transmission electron microscopy (ETEM) in materials science provides exciting new possibilities for investigating chemical reactions and understanding both the interaction of fast electrons with gas molecules and the effect of the presence of gas on high......-resolution imaging. A gaseous atmosphere in the pole-piece gap of the objective lens of the microscope alters both the incoming electron wave prior to interaction with the sample and the outgoing wave below the sample. Whereas conventional TEM samples are usually thin (below 100 nm), the gas in the environmental...... cell fills the entire gap between the pole pieces and is thus not spatially localized. By using an FEI Titan environmental transmission electron microscope equipped with a monochromator and an aberration corrector on the objective lens, we have investigated the effects on imaging and spectroscopy...

  14. Quantification of the Information Limit of Transmission Electron Microscopes

    International Nuclear Information System (INIS)

    Barthel, J.; Thust, A.

    2008-01-01

    The resolving power of high-resolution transmission electron microscopes is characterized by the information limit, which reflects the size of the smallest object detail observable with a particular instrument. We introduce a highly accurate measurement method for the information limit, which is suitable for modern aberration-corrected electron microscopes. An experimental comparison with the traditionally applied Young's fringe method yields severe discrepancies and confirms theoretical considerations according to which the Young's fringe method does not reveal the information limit

  15. 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

  16. Microfluidic chip for high resolution transmission electron microscopy

    DEFF Research Database (Denmark)

    2013-01-01

    A Microfluidic chip (100) for transmission electron microscopy has a monolithic body (101) with a front side (102) and a back side (103). The monolithic body (101) comprises an opening (104) on the back side (103) extending in a vertical direction from the back side (103) to a membrane (107...

  17. 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

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

    DEFF Research Database (Denmark)

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

    2001-01-01

    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...

  19. Security Techniques for the Electronic Health Records.

    Science.gov (United States)

    Kruse, Clemens Scott; Smith, Brenna; Vanderlinden, Hannah; Nealand, Alexandra

    2017-08-01

    The privacy of patients and the security of their information is the most imperative barrier to entry when considering the adoption of electronic health records in the healthcare industry. Considering current legal regulations, this review seeks to analyze and discuss prominent security techniques for healthcare organizations seeking to adopt a secure electronic health records system. Additionally, the researchers sought to establish a foundation for further research for security in the healthcare industry. The researchers utilized the Texas State University Library to gain access to three online databases: PubMed (MEDLINE), CINAHL, and ProQuest Nursing and Allied Health Source. These sources were used to conduct searches on literature concerning security of electronic health records containing several inclusion and exclusion criteria. Researchers collected and analyzed 25 journals and reviews discussing security of electronic health records, 20 of which mentioned specific security methods and techniques. The most frequently mentioned security measures and techniques are categorized into three themes: administrative, physical, and technical safeguards. The sensitive nature of the information contained within electronic health records has prompted the need for advanced security techniques that are able to put these worries at ease. It is imperative for security techniques to cover the vast threats that are present across the three pillars of healthcare.

  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. High-resolution low-dose scanning transmission electron microscopy.

    Science.gov (United States)

    Buban, James P; Ramasse, Quentin; Gipson, Bryant; Browning, Nigel D; Stahlberg, Henning

    2010-01-01

    During the past two decades instrumentation in scanning transmission electron microscopy (STEM) has pushed toward higher intensity electron probes to increase the signal-to-noise ratio of recorded images. While this is suitable for robust specimens, biological specimens require a much reduced electron dose for high-resolution imaging. We describe here protocols for low-dose STEM image recording with a conventional field-emission gun STEM, while maintaining the high-resolution capability of the instrument. Our findings show that a combination of reduced pixel dwell time and reduced gun current can achieve radiation doses comparable to low-dose TEM.

  4. 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...

  5. 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

  6. Transmission and Trapping of Cold Electrons in Water Ice

    DEFF Research Database (Denmark)

    Balog, Richard; Cicman, Peter; Field, David

    2011-01-01

    Experiments are reported that show currents of low energy (“cold”) electrons pass unattenuated through crystalline ice at 135 K for energies between zero and 650 meV, up to the maximum studied film thickness of 430 bilayers, showing negligible apparent trapping. By contrast, both porous amorphous...... ice and compact crystalline ice at 40 K show efficient electron trapping. Ice at intermediate temperatures reveals metastable trapping that decays within a few hundred seconds at 110 K. Our results are the first to demonstrate full transmission of cold electrons in high temperature water ice...

  7. Strain mapping of semiconductor specimens with nm-scale resolution in a transmission electron microscope.

    Science.gov (United States)

    Cooper, David; Denneulin, Thibaud; Bernier, Nicolas; Béché, Armand; Rouvière, Jean-Luc

    2016-01-01

    The last few years have seen a great deal of progress in the development of transmission electron microscopy based techniques for strain mapping. New techniques have appeared such as dark field electron holography and nanobeam diffraction and better known ones such as geometrical phase analysis have been improved by using aberration corrected ultra-stable modern electron microscopes. In this paper we apply dark field electron holography, the geometrical phase analysis of high angle annular dark field scanning transmission electron microscopy images, nanobeam diffraction and precession diffraction, all performed at the state-of-the-art to five different types of semiconductor samples. These include a simple calibration structure comprising 10-nm-thick SiGe layers to benchmark the techniques. A SiGe recessed source and drain device has been examined in order to test their capabilities on 2D structures. Devices that have been strained using a nitride stressor have been examined to test the sensitivity of the different techniques when applied to systems containing low values of deformation. To test the techniques on modern semiconductors, an electrically tested device grown on a SOI wafer has been examined. Finally a GaN/AlN superlattice was tested in order to assess the different methods of measuring deformation on specimens that do not have a perfect crystalline structure. The different deformation mapping techniques have been compared to one another and the strengths and weaknesses of each are discussed. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. 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.

  9. 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

  10. Environmental Transmission Electron Microscopy of catalysts for the methanol synthesis

    DEFF Research Database (Denmark)

    Duchstein, Linus Daniel Leonhard

    Ga. Both were synthesized from Cu and Ni nitrate salts as well as Ni and Ga nitrates salts. Both systems got catalytically tested and investigated by in-situ X-Ray Diffraction (XRD) and Environmental Transmission Electron Microscopy (ETEM). It was possible to follow the synthesis of the catalysts......Ni forms a substitutional alloy. During the reaction and artificial ageing a deactivation of the NiGa due to a phase change could be observed. CuNialso changes the the oxidation state during the reaction. Furthermore the influence of the electron beam on the catalytic systems during exposure to gas...... atmosphere and temperature was investigated. CuNi was exposed to the electron beam for 3 different intensities and 3 different temperatures while the oxidation state of the Cu2+ was measured by energy electron loss spectroscopy. It turns out that the electron beam does have an influence but it does not seem...

  11. Structural studies of glasses by transmission electron microscopy and electron diffraction

    International Nuclear Information System (INIS)

    Kashchieva, E.P.

    1997-01-01

    The purpose of this work is to present information about the applications of transmission electron microscopy (TEM) and electron diffraction (ED) for structural investigations of glasses. TEM investigations have been carried out on some binary and on a large number of ternary borate-telluride systems where glass-forming oxides, oxides of transitional elements and modified oxides of elements from I, II and III groups in the periodic table, are used as third component. The large experimental data given by TEM method allows the fine classification of the micro-heterogeneities. A special case of micro-heterogeneous structure with technological origin occurs near the boundary between the 2 immiscible liquids obtained at macro-phase separation. TEM was also used for the direct observation of the glass structure and we have studied the nano-scale structure of borate glasses obtained at slow and fast cooling of the melts. The ED possesses advantages for analysis of amorphous thin films or micro-pastilles and it is a very useful technique for study in materials containing simultaneously light and heavy elements. A comparison between the possibilities of the 3 diffraction techniques (X-ray diffraction, neutron diffraction and ED) is presented

  12. Accurate virus quantitation using a Scanning Transmission Electron Microscopy (STEM) detector in a scanning electron microscope.

    Science.gov (United States)

    Blancett, Candace D; Fetterer, David P; Koistinen, Keith A; Morazzani, Elaine M; Monninger, Mitchell K; Piper, Ashley E; Kuehl, Kathleen A; Kearney, Brian J; Norris, Sarah L; Rossi, Cynthia A; Glass, Pamela J; Sun, Mei G

    2017-10-01

    A method for accurate quantitation of virus particles has long been sought, but a perfect method still eludes the scientific community. Electron Microscopy (EM) quantitation is a valuable technique because it provides direct morphology information and counts of all viral particles, whether or not they are infectious. In the past, EM negative stain quantitation methods have been cited as inaccurate, non-reproducible, and with detection limits that were too high to be useful. To improve accuracy and reproducibility, we have developed a method termed Scanning Transmission Electron Microscopy - Virus Quantitation (STEM-VQ), which simplifies sample preparation and uses a high throughput STEM detector in a Scanning Electron Microscope (SEM) coupled with commercially available software. In this paper, we demonstrate STEM-VQ with an alphavirus stock preparation to present the method's accuracy and reproducibility, including a comparison of STEM-VQ to viral plaque assay and the ViroCyt Virus Counter. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  13. Transmission scanning electron microscopy: Defect observations and image simulations.

    Science.gov (United States)

    Callahan, Patrick G; Stinville, Jean-Charles; Yao, Eric R; Echlin, McLean P; Titus, Michael S; De Graef, Marc; Gianola, Daniel S; Pollock, Tresa M

    2018-03-01

    The new capabilities of a FEG scanning electron microscope (SEM) equipped with a scanning transmission electron microscopy (STEM) detector for defect characterization have been studied in parallel with transmission electron microscopy (TEM) imaging. Stacking faults and dislocations have been characterized in strontium titanate, a polycrystalline nickel-base superalloy and a single crystal cobalt-base material. Imaging modes that are similar to conventional TEM (CTEM) bright field (BF) and dark field (DF) and STEM are explored, and some of the differences due to the different accelerating voltages highlighted. Defect images have been simulated for the transmission scanning electron microscopy (TSEM) configuration using a scattering matrix formulation, and diffraction contrast in the SEM is discussed in comparison to TEM. Interference effects associated with conventional TEM, such as thickness fringes and bending contours are significantly reduced in TSEM by using a convergent probe, similar to a STEM imaging modality, enabling individual defects to be imaged clearly even in high dislocation density regions. Beyond this, TSEM provides significant advantages for high throughput and dynamic in-situ characterization. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Software electron counting for low-dose scanning transmission electron microscopy.

    Science.gov (United States)

    Mittelberger, Andreas; Kramberger, Christian; Meyer, Jannik C

    2018-02-17

    The performance of the detector is of key importance for low-dose imaging in transmission electron microscopy, and counting every single electron can be considered as the ultimate goal. In scanning transmission electron microscopy, low-dose imaging can be realized by very fast scanning, however, this also introduces artifacts and a loss of resolution in the scan direction. We have developed a software approach to correct for artifacts introduced by fast scans, making use of a scintillator and photomultiplier response that extends over several pixels. The parameters for this correction can be directly extracted from the raw image. Finally, the images can be converted into electron counts. This approach enables low-dose imaging in the scanning transmission electron microscope via high scan speeds while retaining the image quality of artifact-free slower scans. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Scanning electron microscopy and transmission electron microscopy study of hot-deformed gamma-TiAl-based alloy microstructure.

    Science.gov (United States)

    Chrapoński, J; Rodak, K

    2006-09-01

    The aim of this work was to assess the changes in the microstructure of hot-deformed specimens made of alloys containing 46-50 at.% Al, 2 at.% Cr and 2 at.% Nb (and alloying additions such as carbon and boron) with the aid of scanning electron microscopy and transmission electron microscopy techniques. After homogenization and heat treatment performed in order to make diverse lamellae thickness, the specimens were compressed at 1000 degrees C. Transmission electron microscopy examinations of specimens after the compression test revealed the presence of heavily deformed areas with a high density of dislocation. Deformation twins were also observed. Dynamically recrystallized grains were revealed. For alloys no. 2 and no. 3, the recovery and recrystallization processes were more extensive than for alloy no. 1.

  16. Electron tomography of HEK293T cells using scanning electron microscope-based scanning transmission electron microscopy.

    Science.gov (United States)

    You, Yun-Wen; Chang, Hsun-Yun; Liao, Hua-Yang; Kao, Wei-Lun; Yen, Guo-Ji; Chang, Chi-Jen; Tsai, Meng-Hung; Shyue, Jing-Jong

    2012-10-01

    Based on a scanning electron microscope operated at 30 kV with a homemade specimen holder and a multiangle solid-state detector behind the sample, low-kV scanning transmission electron microscopy (STEM) is presented with subsequent electron tomography for three-dimensional (3D) volume structure. Because of the low acceleration voltage, the stronger electron-atom scattering leads to a stronger contrast in the resulting image than standard TEM, especially for light elements. Furthermore, the low-kV STEM yields less radiation damage to the specimen, hence the structure can be preserved. In this work, two-dimensional STEM images of a 1-μm-thick cell section with projection angles between ±50° were collected, and the 3D volume structure was reconstructed using the simultaneous iterative reconstructive technique algorithm with the TomoJ plugin for ImageJ, which are both public domain software. Furthermore, the cross-sectional structure was obtained with the Volume Viewer plugin in ImageJ. Although the tilting angle is constrained and limits the resulting structural resolution, slicing the reconstructed volume generated the depth profile of the thick specimen with sufficient resolution to examine cellular uptake of Au nanoparticles, and the final position of these nanoparticles inside the cell was imaged.

  17. A piezoelectric goniometer inside a transmission electron microscope goniometer.

    Science.gov (United States)

    Guan, Wei; Lockwood, Aiden; Inkson, Beverley J; Möbus, Günter

    2011-10-01

    Piezoelectric nanoactuators, which can provide extremely stable and reproducible positioning, are rapidly becoming the dominant means for position control in transmission electron microscopy. Here we present a second-generation miniature goniometric nanomanipulation system, which is fully piezo-actuated with ultrafine step size for translation and rotation, programmable, and can be fitted inside a hollowed standard specimen holder for a transmission electron microscope (TEM). The movement range of this miniaturized drive is composed of seven degrees of freedom: three fine translational movements (X, Y, and Z axes), three coarse translational movements along all three axes, and one rotational movement around the X-axis with an integrated angular sensor providing absolute rotation feedback. The new piezoelectric system independently operates as a goniometer inside the TEM goniometer. In situ experiments, such as tomographic tilt without missing wedge and differential tilt between two specimens, are demonstrated.

  18. Collaborative Beamforming Techniques for Data Transmission in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    L. Berbakov

    2015-11-01

    Full Text Available Collaborative beamforming is a technique for improving energy efficiency of uplink communications in wireless sensor networks. It is done by synchronizing carrier phases of individual sensor nodes precisely enough, so that they jointly form a beampattern with a stable mainlobe. In this paper, we analyze the impact of additive noise in the received signal on the behavior of an iterative phase synchronization scheme. Besides, we analyze the bit error rate performance of such collaborative transmission. In particular, we consider a decentralized antenna array where sensors are allowed to perform distributed carrier synchronization and collaborative data transmission simultaneously. We evaluate the system performance by using numerical simulations and provide a semi-analytical solution for the algorithm convergence characteristics and the overall bit error rate as a function of the algorithm’s iteration index.

  19. eV-TEM: Transmission electron microscopy in a low energy cathode lens instrument

    Energy Technology Data Exchange (ETDEWEB)

    Geelen, Daniël, E-mail: geelen@physics.leidenuniv.nl [Huygens-Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden (Netherlands); Thete, Aniket [Huygens-Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden (Netherlands); Schaff, Oliver; Kaiser, Alexander [SPECS GmbH, Voltastrasse 5, D-13355 Berlin (Germany); Molen, Sense Jan van der [Huygens-Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden (Netherlands); Tromp, Rudolf [IBM T.J. Watson Research Center, 1101 Kitchawan Road, P.O. Box 218, Yorktown Heights, NY 10598 (United States)

    2015-12-15

    We are developing a transmission electron microscope that operates at extremely low electron energies, 0–40 eV. We call this technique eV-TEM. Its feasibility is based on the fact that at very low electron energies the number of energy loss pathways decreases. Hence, the electron inelastic mean free path increases dramatically. eV-TEM will enable us to study elastic and inelastic interactions of electrons with thin samples. With the recent development of aberration correction in cathode lens instruments, a spatial resolution of a few nm appears within range, even for these very low electron energies. Such resolution will be highly relevant to study biological samples such as proteins and cell membranes. The low electron energies minimize adverse effects due to radiation damage. - Highlights: • We present a new way of performing low energy transmission electron microscopy in an aberration corrected LEEM/PEEM instrument. • We show a proof of principle where we measure transmitted electrons through a suspended graphene monolayer with a preliminary setup. • We present an improved setup design that provides better control of the incident electron beam.

  20. Practical aspects of monochromators developed for transmission electron microscopy

    Science.gov (United States)

    Kimoto, Koji

    2014-01-01

    A few practical aspects of monochromators recently developed for transmission electron microscopy are briefly reviewed. The basic structures and properties of four monochromators, a single Wien filter monochromator, a double Wien filter monochromator, an omega-shaped electrostatic monochromator and an alpha-shaped magnetic monochromator, are outlined. The advantages and side effects of these monochromators in spectroscopy and imaging are pointed out. A few properties of the monochromators in imaging, such as spatial or angular chromaticity, are also discussed. PMID:25125333

  1. 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

  2. Transmission electron microscopy of unstained hybrid Au nanoparticles capped with PPAA (plasma-poly-allylamine)

    DEFF Research Database (Denmark)

    Gontard, Lionel C.; Fernández, Asunción; Dunin-Borkowski, Rafal E.

    2014-01-01

    Hybrid (organic shell-inorganic core) nanoparticles have important applications in nanomedicine. Although the inorganic components of hybrid nanoparticles can be characterized readily using conventional transmission electron microscopy (TEM) techniques, the structural and chemical arrangement...... as a contrast enhancement mechanism for imaging the organic shells of such particles. We also study electron-beam-induced crystallization and amorphization of the shells and the formation of graphitic-like layers that contain both C and N. The resistance of the samples to irradiation by high-energy electrons...

  3. Scanning transmission electron microscopy: Albert Crewe's vision and beyond.

    Science.gov (United States)

    Krivanek, Ondrej L; Chisholm, Matthew F; Murfitt, Matthew F; Dellby, Niklas

    2012-12-01

    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 0.5Å 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. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. 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

  5. Characterization of chiral mesoporous materials by transmission electron microscopy.

    Science.gov (United States)

    Ohsuna, Tetsu; Liu, Zheng; Che, Shunai; Terasaki, Osamu

    2005-02-01

    By using transmission electron microscopy (TEM), the chirality of novel mesoporous materials has been studied. In addition, a computer simulation that uses a simple structural model was employed. The existence of chiral channels inside a tubelike material was confirmed by the observation of fringes along the length of the tubes. The chiral pitch of the channels was measured from the intermittent period, the chirality (right- or left-handed) was determined from the tilt direction of a tube compared with the direction of incident electrons and the curvature direction of the curved intermitted fringes as viewed in the TEM images.

  6. 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.

  7. 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.

  8. 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...

  9. 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.

  10. Transmission electron microscopy of the preclinical phase of experimental phytophotodermatitis

    Directory of Open Access Journals (Sweden)

    Hiram Larangeira de Almeida Jr

    2008-01-01

    Full Text Available OBJECTIVE: To examine the epidermis in induced phytophotodermatitis using transmission electron microscopy in order to detect histologic changes even before lesions are visible by light microscopy. INTRODUCTION: In the first six hours after the experimental induction of phytophotodermatitis, no changes are detectable by light microscopy. Only after 24 hours can keratinocyte necrosis and epidermal vacuolization be detected histologically, and blisters form by 48 hours. METHODS: The dorsum of four adult rats (Rattus norvegicus was manually epilated. After painting the right half of the rat with the peel juice of Tahiti lemon, they were exposed to sunlight for eight minutes under general anesthesia. The left side was used as the control and exposed to sunlight only. Biopsies were performed immediately after photoinduction and one and two hours later, and the tissue was analyzed by transmission electron microscopy. RESULTS: No histological changes were seen on the control side. Immediately after induction, vacuolization in keratinocytes was observed. After one hour, desmosomal changes were also observed in addition to vacuolization. Keratin filaments were not attached to the desmosomal plaque. Free desmosomes and membrane ruptures were also seen. At two hours after induction, similar changes were found, and granular degeneration of keratin was also observed. DISCUSSION: The interaction of sunlight and psoralens generates a photoproduct that damages keratinocyte proteins, leading to keratinocyte necrosis and blister formation. CONCLUSIONS: Transmission electron microscopy can detect vacuolization, lesions of the membrane, and desmosomes in the first two hours after experimental induction of phytophotodermatitis.

  11. Nanoscale Energy-Filtered Scanning Confocal Electron Microscopy Using a Double-Aberration-Corrected Transmission Electron Microscope

    International Nuclear Information System (INIS)

    Wang Peng; Behan, Gavin; Kirkland, Angus I.; Nellist, Peter D.; Takeguchi, Masaki; Hashimoto, Ayako; Mitsuishi, Kazutaka; Shimojo, Masayuki

    2010-01-01

    We demonstrate that a transmission electron microscope fitted with two spherical-aberration correctors can be operated as an energy-filtered scanning confocal electron microscope. A method for establishing this mode is described and initial results showing 3D chemical mapping with nanoscale sensitivity to height and thickness changes in a carbon film are presented. Importantly, uncorrected chromatic aberration does not limit the depth resolution of this technique and moreover performs an energy-filtering role, which is explained in terms of a combined depth and energy-loss response function.

  12. 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

    2018-03-28

    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.

  13. Study of the structure of pyrocarbon coatings of fuel particles by transmission electron microscopy

    International Nuclear Information System (INIS)

    Pollmann, E.; Schuster, H.; Nickel, H.

    1977-07-01

    Pyrocarbon is used as a coating material for fuel particles used in the High Temperature Reactor, and is deposited onto the fuel using a fluidized-bed technique. As a part of a basic research programme the microstructure of this pyrocarbon has been investigated by transmission electron microscopy. The deposition temperature and the concentration of the deposition gas in the fluidized bed were varied between 1,100 and 2,000 0 C and 5 and 60 v/o C 3 H 6 respectively. It is shown that three different types of structure are obtained in the pyrocarbon. The development of these microstructures is dependent on the deposition temperature and the concentration of the deposition gas. The properties of the microstructures, as deduced by transmission electron microscopy, are in agreement with the results of other material characterization techniques. (orig.) [de

  14. Comparison of Heat Affected Zone due to nanosecond and femtosecond laser pulses using Transmission Electronic Microscopy

    OpenAIRE

    Le Harzic, Ronan; Huot, Nicolas; Audouard, Eric; Jonin, Christian; Laporte, Pierre; Valette, Stéphane; Fraczkievic, Anna; Fortunier, Roland

    2002-01-01

    International audience; This letter presents a method aimed at quantifying the dimensions of the heat-affected zone ~HAZ!, produced during nanosecond and femtosecond laser–matter interactions. According to this method, 0.1 mm thick Al samples were microdrilled and observed by a transmission electronic microscopy technique. The holes were produced at laser fluences above the ablation threshold in both nanosecond and femtosecond regimes ~i.e., 5 and 2 J/cm2, respectively!. The grain size in the...

  15. A Transmission Electron Microscope Investigation of Space Weathering Effects in Hayabusa Samples

    Science.gov (United States)

    Keller, Lindsay P.; Berger, Eve L.

    2014-01-01

    The Hayabusa mission to asteroid 25143 Itokawa successfully returned the first direct samples of the regolith from the surface of an asteroid. The Hayabusa samples thus present a special opportunity to directly investigate the evolution of asteroidal surfaces, from the development of the regolith to the study of the more complex effects of space weathering. Here we describe the mineralogy, microstructure and composition of three Hayabusa mission particles using transmission electron microscope (TEM) techniques

  16. Characterization nanoparticles-based vaccines and vaccine candidates: a Transmission Electron Microscopy study

    Directory of Open Access Journals (Sweden)

    I. Menéndez I

    2016-05-01

    Full Text Available Transmission Electron Microscopy (TEM is a valuable tool for the biotech industry. This paper summarizes some of the contributions of MET in the characterization of the recombinant antigens are part of vaccines or vaccine candidates obtained in the CIGB. It mentions the use of complementary techniques MET (Negative staining, and immunoelectron that enhance visualization and ultrastructural characterization of the recombinant proteins obtained by Genetic Engineering.

  17. Characterization of Li-rich layered oxides by using transmission electron microscope

    Directory of Open Access Journals (Sweden)

    Hu Zhao

    2017-07-01

    Full Text Available Lithium-rich layered oxides (LrLOs deliver extremely high specific capacities and are considered to be promising candidates for electric vehicle and smart grid applications. However, the application of LrLOs needs further understanding of the structural complexity and dynamic evolution of monoclinic and rhombohedral phases, in order to overcome the issues including voltage decay, poor rate capability, initial irreversible capacity loss and etc. The development of aberration correction for the transmission electron microscope and concurrent progress in electron spectroscopy, have fueled rapid progress in the understanding of the mechanism of such issues. New techniques based on the transmission electron microscope are first surveyed, and the applications of these techniques for the study of the structure, migration of transition metal, and the activation of oxygen of LrLOs are then explored in detail, with a particular focus on the mechanism of voltage decay. Keywords: Lithium-ion battery, Transmission electron microscope, Lithium-rich layered oxide, Cathode material

  18. 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.

  19. Charging of carbon thin films in scanning and phase-plate transmission electron microscopy.

    Science.gov (United States)

    Hettler, Simon; Kano, Emi; Dries, Manuel; Gerthsen, Dagmar; Pfaffmann, Lukas; Bruns, Michael; Beleggia, Marco; Malac, Marek

    2018-01-01

    A systematic study on charging of carbon thin films under intense electron-beam irradiation was performed in a transmission electron microscope to identify the underlying physics for the functionality of hole-free phase plates. Thin amorphous carbon films fabricated by different deposition techniques and single-layer graphene were studied. Clean thin films at moderate temperatures show small negative charging while thin films kept at an elevated temperature are stable and not prone to beam-generated charging. The charging is attributed to electron-stimulated desorption (ESD) of chemisorbed water molecules from the thin-film surfaces and an accompanying change of work function. The ESD interpretation is supported by experimental results obtained by electron-energy loss spectroscopy, hole-free phase plate imaging, secondary electron detection and x-ray photoelectron spectroscopy as well as simulations of the electrostatic potential distribution. The described ESD-based model explains previous experimental findings and is of general interest to any phase-related technique in a transmission electron microscope. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  20. 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.

  1. 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.

  2. Application of Boltzmann equation to electron transmission and seconary electron emission

    International Nuclear Information System (INIS)

    Lanteri, H.; Bindi, R.; Rostaing, P.

    1979-01-01

    A method is presented for numerical treatment of integro-differential equation, based upon finite difference techniques. This method allows to formulate in a satisfactory manner the Boltzmann's equation applied to backscattering, transmission and secondary emission of metallic targets, avoiding must of the restrictive hypothesis, used until now in these models. For aluminium, the calculated energy spectra, angular distribution, transmission and backscattering coefficients, and secondary emission yield, are found to be in good agreement with experiment [fr

  3. Quantifying the growth of individual graphene layers by in situ environmental transmission electron microscopy

    DEFF Research Database (Denmark)

    Kling, Jens; Hansen, Thomas Willum; Wagner, Jakob Birkedal

    2016-01-01

    The growth dynamics of layered carbon is studied by means of in situ transmission electron microscopy in order to obtain a deeper insight into the growth by chemical vapor deposition, which at present is the technique of choice for growing layered carbon. In situ growth of layered carbon structures...... on nickel using acetylene as carbon precursor gas is studied in the electron microscope at various gas pressures. By following the growth of individual graphene layers on the Ni surface, local growth rates are determined as a function of precursor pressure. Two growth regimes are identified, an initial...

  4. Vibrational and optical spectroscopies integrated with environmental transmission electron microscopy.

    Science.gov (United States)

    Picher, Matthieu; Mazzucco, Stefano; Blankenship, Steve; Sharma, Renu

    2015-03-01

    Here, we present a measurement platform for collecting multiple types of spectroscopy data during high-resolution environmental transmission electron microscopy observations of dynamic processes. Such coupled measurements are made possible by a broadband, high-efficiency, free-space optical system. The critical element of the system is a parabolic mirror, inserted using an independent hollow rod and placed below the sample holder which can focus a light on the sample and/or collect the optical response. We demonstrate the versatility of this optical setup by using it to combine in situ atomic-scale electron microscopy observations with Raman spectroscopy. The Raman data is also used to measure the local temperature of the observed sample area. Other applications include, but are not limited to: cathodo- and photoluminescence spectroscopy, and use of the laser as a local, high-rate heating source. Published by Elsevier B.V.

  5. High current nonlinear transmission line based electron beam driver

    Directory of Open Access Journals (Sweden)

    B. W. Hoff

    2017-10-01

    Full Text Available A gigawatt-class nonlinear transmission line based electron beam driver is experimentally demonstrated. Four experimental series, each with a different Marx bank charge voltage (15, 20, 25, and 30 kV, were completed. Within each experimental series, shots at peak frequencies ranging from 950 MHz to 1.45 GHz were performed. Peak amplitude modulations of the NLTL output voltage signal were found to range between 18% and 35% for the lowest frequency shots and between 5% and 20% for the highest frequency shots (higher modulation at higher Marx charge voltage. Peak amplitude modulations of the electron beam current were found to range between 10% and 20% for the lowest frequency shots and between 2% and 7% for the highest frequency shots (higher modulation at higher Marx charge voltage.

  6. High current nonlinear transmission line based electron beam driver

    Science.gov (United States)

    Hoff, B. W.; French, D. M.; Simon, D. S.; Lepell, P. D.; Montoya, T.; Heidger, S. L.

    2017-10-01

    A gigawatt-class nonlinear transmission line based electron beam driver is experimentally demonstrated. Four experimental series, each with a different Marx bank charge voltage (15, 20, 25, and 30 kV), were completed. Within each experimental series, shots at peak frequencies ranging from 950 MHz to 1.45 GHz were performed. Peak amplitude modulations of the NLTL output voltage signal were found to range between 18% and 35% for the lowest frequency shots and between 5% and 20% for the highest frequency shots (higher modulation at higher Marx charge voltage). Peak amplitude modulations of the electron beam current were found to range between 10% and 20% for the lowest frequency shots and between 2% and 7% for the highest frequency shots (higher modulation at higher Marx charge voltage).

  7. In Situ Electronic Characterization of Graphene Nanoconstrictions Fabricated in a Transmission Electron Microscope

    OpenAIRE

    Lu, Ye; Merchant, Christopher A.; Drndić, Marija; Johnson, A. T. Charlie

    2011-01-01

    We report electronic measurements on high-quality graphene nanoconstrictions (GNCs) fabricated in a transmission electron microscope (TEM), and the first measurements on GNC conductance with an accurate measurement of constriction width down to 1 nm. To create the GNCs, freely-suspended graphene ribbons were fabricated using few-layer graphene grown by chemical vapor deposition. The ribbons were loaded into the TEM, and a current-annealing procedure was used to clean the material and improve ...

  8. Current status and future directions for in situ transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Taheri, Mitra L. [Department of Materials Science and Engineering, Drexel University (United States); Stach, Eric A. [Center for Functional Nanomaterials, National Laboratory, Brookhaven (United States); Arslan, Ilke [Pacific Northwest National Laboratory, Physical and Computational Sciences Directorate, 902 Battelle Blvd, Richland, WA (United States); Crozier, P.A. [School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ 85281 (United States); Kabius, Bernd C. [The Pennsylvania State University, University Park, PA 16802 (United States); LaGrange, Thomas [Lawrence Livermore National Laboratory, Physical and Life Science Directorate, Condensed Matter and Materials Division, 7000 East Avenue, P.O. 808 L-356 (United States); Minor, Andrew M. [Department of Materials Science & Engineering, University of California, Berkeley and National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Road, MS 72, Berkeley, CA (United States); Takeda, Seiji [Institute of Scientific and Industrial Research (ISIR), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Tanase, Mihaela [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899-6203 (United States); Wagner, Jakob B. [Center for Electron Nanoscopy, Technical University of Denmark, Kgs, Lyngby (Denmark); Sharma, Renu, E-mail: renu.sharma@nist.gov [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899-6203 (United States)

    2016-11-15

    This review article discusses the current and future possibilities for the application of in situ transmission electron microscopy to reveal synthesis pathways and functional mechanisms in complex and nanoscale materials. The findings of a group of scientists, representing academia, government labs and private sector entities (predominantly commercial vendors) during a workshop, held at the Center for Nanoscale Science and Technology- National Institute of Science and Technology (CNST-NIST), are discussed. We provide a comprehensive review of the scientific needs and future instrument and technique developments required to meet them. - Highlights: • Evaluation of currently available technology for performing in situ experiments using transmission electron microscope. • Limitations of currently available instrumentation with respect to base TEM, specialty TEM holders, and data acquisition systems. • Guidelines and wish list for the areas of future development.

  9. Current status and future directions for in situ transmission electron microscopy

    International Nuclear Information System (INIS)

    Taheri, Mitra L.; Stach, Eric A.; Arslan, Ilke; Crozier, P.A.; Kabius, Bernd C.; LaGrange, Thomas; Minor, Andrew M.; Takeda, Seiji; Tanase, Mihaela; Wagner, Jakob B.; Sharma, Renu

    2016-01-01

    This review article discusses the current and future possibilities for the application of in situ transmission electron microscopy to reveal synthesis pathways and functional mechanisms in complex and nanoscale materials. The findings of a group of scientists, representing academia, government labs and private sector entities (predominantly commercial vendors) during a workshop, held at the Center for Nanoscale Science and Technology- National Institute of Science and Technology (CNST-NIST), are discussed. We provide a comprehensive review of the scientific needs and future instrument and technique developments required to meet them. - Highlights: • Evaluation of currently available technology for performing in situ experiments using transmission electron microscope. • Limitations of currently available instrumentation with respect to base TEM, specialty TEM holders, and data acquisition systems. • Guidelines and wish list for the areas of future development.

  10. Addressing preservation of elastic contrast in energy-filtered transmission electron microscopy.

    Science.gov (United States)

    Brown, H G; D'Alfonso, A J; Forbes, B D; Allen, L J

    2016-01-01

    Energy-filtered transmission electron microscopy (EFTEM) images with resolutions of the order of an Ångström can be obtained using modern microscopes corrected for chromatic aberration. However, the delocalized nature of the transition potentials for atomic ionization often confounds direct interpretation of EFTEM images, leading to what is known as "preservation of elastic contrast". In this paper we demonstrate how more interpretable images might be obtained by scanning with a focused coherent probe and incoherently averaging the energy-filtered images over probe position. We dub this new imaging technique energy-filtered imaging scanning transmission electron microscopy (EFISTEM). We develop a theoretical framework for EFISTEM and show that it is in fact equivalent to precession EFTEM, where the plane wave illumination is precessed through a range of tilts spanning the same range of angles as the probe forming aperture in EFISTEM. It is demonstrated that EFISTEM delivers similar results to scanning transmission electron microscopy with an electron energy-loss spectrometer but has the advantage that it is immune to coherent aberrations and spatial incoherence of the probe and is also more resilient to scan distortions. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Nuclear Electronics: Superconducting Detectors and Processing Techniques

    Science.gov (United States)

    Polushkin, Vladimir

    2004-06-01

    With the commercialisation of superconducting particles and radiation detectors set to occur in the very near future, nuclear analytical instrumentation is taking a big step forward. These new detectors have a high degree of accuracy, stability and speed and are suitable for high-density multiplex integration in nuclear research laboratories and astrophysics. Furthermore, superconducting detectors can also be successfully applied to food safety, airport security systems, medical examinations, doping tests & forensic investigations. This book is the first to address a new generation of analytical tools based on new superconductor detectors demonstrating outstanding performance unsurpassed by any other conventional devices. Presenting the latest research and development in nanometer technologies and biochemistry this book: * Discusses the development of nuclear sensing techniques. * Provides guidance on the design and use of the next generation of detectors. * Describes cryogenic detectors for nuclear measurements and spectrometry. * Covers primary detectors, front-end readout electronics and digital signal processing. * Presents applications in nanotechnology and modern biochemistry including DNA sequencing, proteinomics, microorganisms. * Features examples of two applications in X-ray electron probe nanoanalysis and time-of-flight mass spectrometry. This comprehensive treatment is the ideal reference for researchers, industrial engineers and graduate students involved in the development of high precision nuclear measurements, nuclear analytical instrumentation and advanced superconductor primary sensors. This book will also appeal to physicists, electrical and electronic engineers in the nuclear industry.

  12. 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.

  13. 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.

  14. Improved Zernike-type phase contrast for transmission electron microscopy.

    Science.gov (United States)

    Koeck, P J B

    2015-07-01

    Zernike phase contrast has been recognized as a means of recording high-resolution images with high contrast using a transmission electron microscope. This imaging mode can be used to image typical phase objects such as unstained biological molecules or cryosections of biological tissue. According to the original proposal discussed in Danev and Nagayama (2001) and references therein, the Zernike phase plate applies a phase shift of π/2 to all scattered electron beams outside a given scattering angle and an image is recorded at Gaussian focus or slight underfocus (below Scherzer defocus). Alternatively, a phase shift of -π/2 is applied to the central beam using the Boersch phase plate. The resulting image will have an almost perfect contrast transfer function (close to 1) from a given lowest spatial frequency up to a maximum resolution determined by the wave length, the amount of defocus and the spherical aberration of the microscope. In this paper, I present theory and simulations showing that this maximum spatial frequency can be increased considerably without loss of contrast by using a Zernike or Boersch phase plate that leads to a phase shift between scattered and unscattered electrons of only π /4, and recording images at Scherzer defocus. The maximum resolution can be improved even more by imaging at extended Scherzer defocus, though at the cost of contrast loss at lower spatial frequencies. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  15. 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

  16. Big Data Analytics for Scanning Transmission Electron Microscopy Ptychography

    OpenAIRE

    Jesse, S.; Chi, M.; Belianinov, A.; Beekman, C.; Kalinin, S. V.; Borisevich, A. Y.; Lupini, A. R.

    2016-01-01

    Electron microscopy is undergoing a transition; from the model of producing only a few micrographs, through the current state where many images and spectra can be digitally recorded, to a new mode where very large volumes of data (movies, ptychographic and multi-dimensional series) can be rapidly obtained. Here, we discuss the application of so-called ?big-data? methods to high dimensional microscopy data, using unsupervised multivariate statistical techniques, in order to explore salient ima...

  17. 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

  18. Composition analysis of coaxially grown InGaN multi quantum wells using scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Aschenbrenner, T.; Schowalter, M.; Mehrtens, T.; Müller-Caspary, K.; Rosenauer, A.; Fikry, M.; Heinz, D.; Scholz, F.; Tischer, I.; Madel, M.; Thonke, K.; Hommel, D.

    2016-01-01

    GaN nanotubes with coaxial InGaN quantum wells were analyzed by scanning transmission electron microscopy in order to determine their structural properties as well as the indium distribution across the InGaN quantum wells. For the latter, two process steps are necessary. First, a technique to prepare cross-sectional slices out of the nanotubes has been developed. Second, an existing scanning transmission electron microscopy analysis technique has been extended with respect to the special crystallographic orientation of this type of specimen. In particular, the shape of the nanotubes, their defect structure, and the incorporation of indium on different facets were investigated. The quantum wells preferentially grow on m-planes of the dodecagonally shaped nanotubes and on semipolar top facets while no significant indium signal was found on a-planes. An averaged indium concentration of 6% to 7% was found by scanning transmission electron microscopy analysis and could be confirmed by cathodoluminescence measurements.

  19. Annular dark field transmission electron microscopy for protein structure determination.

    Science.gov (United States)

    Koeck, Philip J B

    2016-02-01

    Recently annular dark field (ADF) transmission electron microscopy (TEM) has been advocated as a means of recording images of biological specimens with better signal to noise ratio (SNR) than regular bright field images. I investigate whether and how such images could be used to determine the three-dimensional structure of proteins given that an ADF aperture with a suitable pass-band can be manufactured and used in practice. I develop an approximate theory of ADF-TEM image formation for weak amplitude and phase objects and test this theory using computer simulations. I also test whether these simulated images can be used to calculate a three-dimensional model of the protein using standard software and discuss problems and possible ways to overcome these. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. 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.

  1. Implementing Transmission Electron Backscatter Diffraction for Atom Probe Tomography.

    Science.gov (United States)

    Rice, Katherine P; Chen, Yimeng; Prosa, Ty J; Larson, David J

    2016-06-01

    There are advantages to performing transmission electron backscattering diffraction (tEBSD) in conjunction with focused ion beam-based specimen preparation for atom probe tomography (APT). Although tEBSD allows users to identify the position and character of grain boundaries, which can then be combined with APT to provide full chemical and orientation characterization of grain boundaries, tEBSD can also provide imaging information that improves the APT specimen preparation process by insuring proper placement of the targeted grain boundary within an APT specimen. In this report we discuss sample tilt angles, ion beam milling energies, and other considerations to optimize Kikuchi diffraction pattern quality for the APT specimen geometry. Coordinated specimen preparation and analysis of a grain boundary in a Ni-based Inconel 600 alloy is used to illustrate the approach revealing a 50° misorientation and trace element segregation to the grain boundary.

  2. High quality ultrafast transmission electron microscopy using resonant microwave cavities.

    Science.gov (United States)

    Verhoeven, W; van Rens, J F M; Kieft, E R; Mutsaers, P H A; Luiten, O J

    2018-03-10

    Ultrashort, low-emittance electron pulses can be created at a high repetition rate by using a TM 110 deflection cavity to sweep a continuous beam across an aperture. These pulses can be used for time-resolved electron microscopy with atomic spatial and temporal resolution at relatively large average currents. In order to demonstrate this, a cavity has been inserted in a transmission electron microscope, and picosecond pulses have been created. No significant increase of either emittance or energy spread has been measured for these pulses. At a peak current of 814 ± 2 pA, the root-mean-square transverse normalized emittance of the electron pulses is ɛ n,x =(2.7±0.1)·10 -12  m rad in the direction parallel to the streak of the cavity, and ɛ n,y =(2.5±0.1)·10 -12  m rad in the perpendicular direction for pulses with a pulse length of 1.1-1.3 ps. Under the same conditions, the emittance of the continuous beam is ɛ n,x =ɛ n,y =(2.5±0.1)·10 -12  m rad. Furthermore, for both the pulsed and the continuous beam a full width at half maximum energy spread of 0.95 ± 0.05 eV has been measured. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Development of wavelength-dispersive soft X-ray emission spectrometers for transmission electron microscopes--an introduction of valence electron spectroscopy for transmission electron microscopy.

    Science.gov (United States)

    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 Malpha-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 pi- and sigma-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.

  4. Environmental transmission electron microscopy for catalyst materials using a spherical aberration corrector

    International Nuclear Information System (INIS)

    Takeda, Seiji; Kuwauchi, Yasufumi; Yoshida, Hideto

    2015-01-01

    Atomic resolution has been obtained using environmental transmission electron microscopy (ETEM) by installing a spherical aberration corrector (Cs-corrector) on the objective lens. Simultaneously, the technology for controlling the environment around a specimen in ETEM has advanced significantly in the past decade. Quantification methodology has recently been established for deriving relevant experimental data in catalyst materials from substantial and systematic ETEM observation at the atomic scale. With this background, this paper summarizes aspects of the evolutional microscopy technique: necessary conditions for atomic resolution in ETEM; reduction of the scattering of electrons by the medium surrounding a specimen; and an environmental cell for structural imaging of a crystalline specimen. The high spatial resolution of a Cs-corrected ETEM is demonstrated for different observation conditions. After statistical analysis combined with numerical image analysis of ETEM data is briefly described, the recent applications of the Cs-corrected ETEM to catalyst materials are reviewed. For gold nanoparticulate catalysts, the structural information on the reaction sites and adsorption sites are deduced. For Pt nanoparticulate catalysts, ETEM studies elucidate the correlation between the catalytic activity and the morphology of the nanoparticles. These studies also reveal oxidation and reduction on the topmost Pt surface layer at the atomic scale. Finally, current issues and the future perspectives of Cs-corrected ETEM are summarized, including the reproducibility of ETEM observation data, the control of environments, the critical evaluation of electron irradiation effects, the full implementation of transmission electron microscopy technology in ETEM, and the safety issues for an ETEM laboratory. - Highlights: • Advancement of Cs corrected environmental transmission electron microscopy. • Structural determination of catalyst materials in reaction environments.

  5. Dissociative electron attachment, electron transmission, and electron energy-loss study of the temporary negative ion of acetylene

    International Nuclear Information System (INIS)

    Dressler, R.; Allan, M.

    1987-01-01

    The three title electron-impact techniques are used to study the ground and excited states of acetylene negative ion and their decay processes. The π* resonance at 2.6 eV predissociates into C 2 H - and H. Four narrow resonances are observed in the transmission spectrum in the 7.5--9.5 eV region and assigned to Feshbach and core-excited shape resonances with double occupation of Rydberg orbitals and ground state positive ion core. These four resonances decay into low-lying Rydberg states of neutral acetylene, the first two undergo quasiresonant autodetachment ejecting low energy ( - 2 . One additional resonance is observed in the C - 2 yield, which is not observable in other decay channels. The shapes of the dissociative attachment bands differ qualitatively from the band shapes of the parent and grandparent states, indicating either a strong v dependence of the dissociation rate or the admixture of σ* orbitals in some of the dissociating anion states

  6. Microwave Transmission Measurement of the Electron Cloud Density in the Positron Ring of PEP-II

    CERN Document Server

    Pivi, M T F; Byrd, J; De Santis, S; Sonnad, K G; Caspers, Friedhelm; Kroyer, T; Roncarolo, F

    2008-01-01

    Clouds of electrons in the vacuum chambers of accelerators of positively charged particle beams present a serious limitation for operation of these machines at high currents. Because of the size of these accelerators, it is difficult to probe the low energy electron clouds over substantial lengths of the beam pipe. We applied a novel technique to directly measure the electron cloud density via the phase shift induced in a TE wave which is independently excited and transmitted over a straight section of the accelerator. The modulation in the wave transmission which appear to increase in depth when the clearing solenoids are switched off, seem to be directly correlated to the electron cloud density in the section. Furthermore, we expect a larger phase shift of a wave transmitted through magnetic dipole field regions if the transmitted wave couples with the gyration motion of the electrons. We have used this technique to measure the average electron cloud density (ECD) specifically for the first time in magnetic...

  7. 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.

  8. 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

  9. 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).

  10. Crystallographic tool box (CrysTBox): automated tools for transmission electron microscopists and crystallographers

    Czech Academy of Sciences Publication Activity Database

    Klinger, Miloslav; Jäger, Aleš

    2015-01-01

    Roč. 48, č. 6 (2015), s. 2012-2018 ISSN 0021-8898 R&D Projects: GA ČR GBP108/12/G043 Institutional support: RVO:68378271 Keywords : electron diffraction * automated analysis * transmission electron microscopy * high-resolution transmission electron microscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.720, year: 2014

  11. A Q-Modulation Technique for Efficient Inductive Power Transmission.

    Science.gov (United States)

    Kiani, Mehdi; Lee, Byunghun; Yeon, Pyungwoo; Ghovanloo, Maysam

    2015-12-01

    A fully-integrated power management ASIC for efficient inductive power transmission has been presented capable of automatic load transformation using a method, called Q-modulation. Q-modulation is an adaptive scheme that offers load matching against a wide range of loading ( R L ) and coupling distance ( d 23 ) variations in inductive links to maintain high power transfer efficiency (PTE). It is suitable for inductive powering implantable microelectronic devices (IMDs), recharging mobile electronics, and electric vehicles. In Q-modulation, the zero-crossings of the induced current in the receiver (Rx) LC-tank are detected and a low-loss switch chops the Rx LC-tank for part of the power carrier cycle to form a high-Q LC-tank and store the maximum energy, which is then transferred to R L by opening the switch. By adjusting the duty cycle ( D ), the loaded-Q of the Rx LC-tank can be dynamically modulated to compensate for variations in R L . A Q-modulation power management (QMPM) prototype chip was fabricated in a 0.35-μm standard CMOS process, occupying 4.8 mm 2 . In a 1.45 W wireless power transfer setup, using a class-E power amplifier (PA) operating at 2 MHz, the QMPM successfully increased the inductive link PTE and the overall power efficiency by 98.5% and 120.7% at d 23 = 8 cm, respectively, by compensating for 150 Ω variation in R L at D = 45%.

  12. 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.

  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. Transmission electron microscopy and the molecular structure of icosahedral viruses.

    Science.gov (United States)

    San Martín, Carmen

    2015-09-01

    The field of structural virology developed in parallel with methodological advances in X-ray crystallography and cryo-electron microscopy. At the end of the 1970s, crystallography yielded the first high resolution structure of an icosahedral virus, the T=3 tomato bushy stunt virus at 2.9Å. It took longer to reach near-atomic resolution in three-dimensional virus maps derived from electron microscopy data, but this was finally achieved, with the solution of complex icosahedral capsids such as the T=25 human adenovirus at ∼3.5Å. Both techniques now work hand-in-hand to determine those aspects of virus assembly and biology that remain unclear. This review examines the trajectory followed by EM imaging techniques in showing the molecular structure of icosahedral viruses, from the first two-dimensional negative staining images of capsids to the latest sophisticated techniques that provide high resolution three-dimensional data, or snapshots of the conformational changes necessary to complete the infectious cycle. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Approaches to modelling irradiation-induced processes in transmission electron microscopy.

    Science.gov (United States)

    Skowron, Stephen T; Lebedeva, Irina V; Popov, Andrey M; Bichoutskaia, Elena

    2013-08-07

    The recent progress in high-resolution transmission electron microscopy (HRTEM) has given rise to the possibility of in situ observations of nanostructure transformations and chemical reactions induced by electron irradiation. In this article we briefly summarise experimental observations and discuss in detail atomistic modelling of irradiation-induced processes in HRTEM, as well as mechanisms of such processes recognised due to modelling. Accurate molecular dynamics (MD) techniques based on first principles or tight-binding models are employed in the analysis of single irradiation-induced events, and classical MD simulations are combined with a kinetic Monte Carlo algorithm to simulate continuous irradiation of nanomaterials. It has been shown that sulphur-terminated graphene nanoribbons are formed inside carbon nanotubes as a result of an irradiation-selective chemical reaction. The process of fullerene formation in HRTEM during continuous electron irradiation of a small graphene flake has been simulated, and mechanisms driving this transformation analysed.

  16. Temporal and spatial imaging of hydrogen storage materials: watching solvent and hydrogen desorption from aluminium hydride by transmission electron microscopy.

    Science.gov (United States)

    Beattie, Shane D; Humphries, Terry; Weaver, Louise; McGrady, G Sean

    2008-10-07

    An in situ thermal desorption study of solvated aluminum hydride (alane) by transmission electron microscopy and selected area diffraction has permitted characterisation of the structural and morphological changes during desorption of solvent and hydrogen in real-time; this powerful technique for studying hydrogen storage materials complements several others already employed.

  17. Integrated Transmission Electron and Single‐Molecule Fluorescence Microscopy Correlates Reactivity with Ultrastructure in a Single Catalyst Particle

    OpenAIRE

    Hendriks, Frank C.; Mohammadian, Sajjad; Ristanović, Zoran; Kalirai, Sam; Meirer, Florian; Vogt, Eelco T. C.; Bruijnincx, Pieter C. A.; Gerritsen, Hans C.; Weckhuysen, Bert M.

    2017-01-01

    Abstract Establishing structure–activity relationships in complex, hierarchically structured nanomaterials, such as fluid catalytic cracking (FCC) catalysts, requires characterization with complementary, correlated analysis techniques. An integrated setup has been developed to perform transmission electron microscopy (TEM) and single‐molecule fluorescence (SMF) microscopy on such nanostructured samples. Correlated structure–reactivity information was obtained for 100 nm thin, microtomed secti...

  18. Integrated Transmission Electron and Single-Molecule Fluorescence Microscopy Correlates Reactivity with Ultrastructure in a Single Catalyst Particle

    OpenAIRE

    Hendriks, Frank C.; Mohammadian, Sajjad; Ristanovic, Zoran; Kalirai, Samanbir; Meirer, Florian; Vogt, Eelco T. C.; Bruijnincx, Pieter C. A.; Gerritsen, Hans; Weckhuysen, Bert M.

    2018-01-01

    Establishing structure–activity relationships in complex, hierarchically structured nanomaterials, such as fluid catalytic cracking (FCC) catalysts, requires characterization with complementary, correlated analysis techniques. An integrated setup has been developed to perform transmission electron microscopy (TEM) and single-molecule fluorescence (SMF) microscopy on such nanostructured samples. Correlated structure–reactivity information was obtained for 100 nm thin, microtomed sections of a ...

  19. 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

  20. Localization of human immunodeficiency virus antigens in infected cells by scanning/transmission-immunogold techniques

    International Nuclear Information System (INIS)

    Herrera, M.I.; Santa Maria, I.; de Andres, R.; Najera, R.

    1988-01-01

    An application of high resolution scanning/transmission electron microscopy (STEM) and gold-labelling techniques for the rapid detection of human immunodeficiency virus (HIV) in infected cells has been developed. Experimental in vitro studies for detecting two HIV structural proteins, gp41 and p17, were performed following an indirect labeling procedure that uses monoclonal anti-p17 and anti-gp41 antibodies as primary antibodies and 40 nm gold-linked goat antimouse IgG as secondary antibodies. The cells were then studied by STEM in the scanning mode. Unambiguous localization of the viral antigens was possible by combining the three-dimensional image provided by the secondary electron image and the atomic number-dependent backscattered electron image for the identification of the gold marker. This technique combines both the morphological information and the rapid procedures of scanning electron microscopy with the precise and sensitive antigen detection provided by the use of STEM and immunological methods. The preliminary results of its application to the study of peripheral blood mononuclear cells from four anti-HIV-seropositive patients showing the presence of specific labeling in all of them suggest that it might prove useful for early detection of HIV infection before seroconversion, as well as for quantitative studies

  1. Determination of the cork bark porosity through the gamma ray transmission technology and electronic scanning microscopy image analysis

    International Nuclear Information System (INIS)

    Moraes, Antonio M.C.; Moreira, Anderson C.; Appoloni, Carlos R.

    2007-01-01

    This work applies the gamma transmission techniques (GTR) and imaging by scanning electron microscopy (SEM) for determination of porosity in the sparkling wine bottle corks. The gamma transmission experimental apparatus consists of a micrometric table (ZX) of sample movement automated, a Am-241 source (59,53 keV, 100 mCi), lead collimators, sample-holder, Na I(Tl) detector and appropriated electronics. For the microscopic images an FEI (Quanta 200), electronic microscope with associated electronics was used, and the image analysis was performed with IMAGO software. The average porosity for 22 samples analysed by GTR was of φ=58 +- 4.6 percent. By the imaging technique the found average porosity was φ=60.0 +- 6.2 percent. (author)

  2. Current status and future directions for in situ transmission electron microscopy

    Science.gov (United States)

    Taheri, Mitra L.; Stach, Eric A.; Arslan, Ilke; Crozier, P.A.; Kabius, Bernd C.; LaGrange, Thomas; Minor, Andrew M.; Takeda, Seiji; Tanase, Mihaela; Wagner, Jakob B.; Sharma, Renu

    2016-01-01

    This review article discusses the current and future possibilities for the application of in situ transmission electron microscopy to reveal synthesis pathways and functional mechanisms in complex and nanoscale materials. The findings of a group of scientists, representing academia, government labs and private sector entities (predominantly commercial vendors) during a workshop, held at the Center for Nanoscale Science and Technology- National Institute of Science and Technology (CNST-NIST), are discussed. We provide a comprehensive review of the scientific needs and future instrument and technique developments required to meet them. PMID:27566048

  3. (CryoTransmission Electron Microscopy of Phospholipid Model Membranes Interacting with Amphiphilic and Polyphilic Molecules

    Directory of Open Access Journals (Sweden)

    Annette Meister

    2017-10-01

    Full Text Available Lipid membranes can incorporate amphiphilic or polyphilic molecules leading to specific functionalities and to adaptable properties of the lipid bilayer host. The insertion of guest molecules into membranes frequently induces changes in the shape of the lipid matrix that can be visualized by transmission electron microscopy (TEM techniques. Here, we review the use of stained and vitrified specimens in (cryoTEM to characterize the morphology of amphiphilic and polyphilic molecules upon insertion into phospholipid model membranes. Special emphasis is placed on the impact of novel synthetic amphiphilic and polyphilic bolalipids and polymers on membrane integrity and shape stability.

  4. Biominerals at the nanoscale: transmission electron microscopy methods for studying the special properties of biominerals

    DEFF Research Database (Denmark)

    Posfai, Mihaly; Kasama, Takeshi; Dunin-Borkowski, Rafal E.

    2013-01-01

    textures, and magnetic properties of biominerals at the nanoscale. In this chapter, we review the state of the art in the application of TEM techniques to the study of these properties, both in biomineral crystals and at the inorganic-organic interface. Examples are taken primarily from studies of magnetic...... fields. In order to fulfill their roles in organisms, biominerals have strictly controlled physical and chemical properties. Transmission electron microscopy (TEM) is ideally suited for the study of the structures, arrangements, compositions, morphologies, crystallographic orientations, crystallographic...

  5. 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...

  6. Electron-beam broadening in amorphous carbon films in low-energy scanning transmission electron microscopy.

    Science.gov (United States)

    Drees, H; Müller, E; Dries, M; Gerthsen, D

    2018-02-01

    Resolution in scanning transmission electron microscopy (STEM) is ultimately limited by the diameter of the electron beam. The electron beam diameter is not only determined by the properties of the condenser lens system but also by electron scattering in the specimen which leads to electron-beam broadening and degradation of the resolution with increasing specimen thickness. In this work we introduce a new method to measure electron-beam broadening which is based on STEM imaging with a multi-segmented STEM detector. We focus on STEM at low electron energies between 10 and 30 keV and use an amorphous carbon film with known thickness as test object. The experimental results are compared with calculated beam diameters using different analytical models and Monte-Carlo simulations. We find excellent agreement of the experimental data with the recently published model by Gauvin and Rudinsky [1] for small t/λ el (thickness to elastic mean free path) values which are considered in our study. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Hepatitis C virus transmission in hemodialysis units: importance of infection control practices and aseptic technique.

    Science.gov (United States)

    Thompson, Nicola D; Novak, Ryan T; Datta, Deblina; Cotter, Susanne; Arduino, Matthew J; Patel, Priti R; Williams, Ian T; Bialek, Stephanie R

    2009-09-01

    We investigated 4 hepatitis C virus (HCV) infection outbreaks at hemodialysis units to identify practices associated with transmission. Apparent failures to follow recommended infection control precautions resulted in patient-to-patient HCV transmission, through cross-contamination of the environment or intravenous medication vials. Fastidious attention to aseptic technique and infection control precautions are essential to prevent HCV transmission.

  8. Preparation of herpes simplex virus-infected primary neurons for transmission electron microscopy.

    Science.gov (United States)

    Miranda-Saksena, Monica; Boadle, Ross; Cunningham, Anthony L

    2014-01-01

    Transmission electron microscopy (TEM) provides the resolution necessary to identify both viruses and subcellular components of cells infected with many types of viruses, including herpes simplex virus. Recognized as a powerful tool in both diagnostic and research-based virology laboratories, TEM has made possible the identification of new viruses and has contributed to the elucidation of virus life cycle and virus-host cell interaction. Whilst there are many sample preparation techniques for TEM, conventional processing using chemical fixation and resin embedding remains a useful technique, available in virtually all EM laboratories, for studying virus/cell ultrastructure. In this chapter, we describe the preparation of herpes simplex virus-infected primary neurons, grown on plastic cover slips, to allow sectioning of neurons and axons in their growth plane. This technique allows TEM examination of cell bodies, axons, growth cones, and varicosities, providing powerful insights into virus-cell interaction.

  9. 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.

  10. Light and transmission electronic microscopy evaluation of lyophilized corneas.

    Science.gov (United States)

    Farias, Roberta J M; Sousa, Luciene B; Lima Filho, Acácio A S; Lourenço, Andréa C S; Tanakai, Márcia H; Freymuller, Edna

    2008-08-01

    Cornea storage for longer periods is still a challenge for corneal surgeons. The purpose of this study was to find a method to lyophilize corneas for anterior lamellar transplant and to evaluate them by light and transmission electronic microscopy. Corneal flaps were created by using a microkeratome. Corneas were lyophilized with a cryoprotectant (2.3 mol sacarousis for 40 minutes) and without a cryoprotectant in a lyophilization machine (Modulyon D). The corneas were rehydrated with distilled water, balanced saline solution (BSS), and phosphate-buffered saline, after which they were evaluated by microscopy. A cornea that did not undergo lyophilization served as a control. Lyophilization without a cryoprotectant did not preserve the corneal structure. This finding was also observed when lyophilizing and rehydrating the corneas with distilled water or phosphate-buffered saline. We found that lyophilizing corneas and rehydrating them with 11 mL of BSS for 30 minutes preserved the general corneal structure, the parallelism of the collagen fibers, the Bowman layer, and the epithelial basement membrane for 15 and 30 days and for as long as 1 year or more. Lyophilization with sacarousis and rehydration with BSS may be a good method for anterior lamellar transplantation.

  11. Transmission electron microscopy (TEM) study of minerals in coal

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Kuang-Chien [Univ. of Illinois, Urbana-Champaign, IL (United States)

    1982-01-01

    Minerals in eight coals from different mines were characterized in the micron-size range by using analytical transmission electron microscopy. Specimens were thinned by ion-milling wafers cut from these coals; a cold stage cooled by liquid nitrogen was used to reduce thermal degradation of the minerals by the ion-beam. Different mineral compounds were observed in different coals. The major minerals are clays, sulfides, oxides, carbonates and some minor-element-bearing phosphates. Clays (kaolinite, illite and others) have been most commonly found as either flat sheets or round globules. Iron sulfide was mostly found in the No. 5 and No. 6 coals from Illinois, distributed as massive polycrystals, as clusters of single crystals (framboids) or as isolated single crystals with size range down to some 0.25 microns. Other sulfides and some oxides were found in other coals with particle size as small as some 200 angstroms. Quartz, titanium oxides and many other carbonates and phosphate compounds were also characterized. Brief TEM work in the organic mass of coal was also introduced to study the nature of the coal macerals.

  12. Nanomaterial engineering and property studies in a transmission electron microscope.

    Science.gov (United States)

    Golberg, Dmitri; Costa, Pedro M F J; Wang, Ming-Sheng; Wei, Xianlong; Tang, Dai-Ming; Xu, Zhi; Huang, Yang; Gautam, Ujjal K; Liu, Baodan; Zeng, Haibo; Kawamoto, Naoyki; Zhi, Chunyi; Mitome, Masanori; Bando, Yoshio

    2012-01-10

    Modern methods of in situ transmission electron microscopy (TEM) allow one to not only manipulate with a nanoscale object at the nanometer-range precision but also to get deep insights into its physical and chemical statuses. Dedicated TEM holders combining the capabilities of a conventional high-resolution TEM instrument and atomic force -, and/or scanning tunneling microscopy probes become the powerful tools in nanomaterials analysis. This progress report highlights the past, present and future of these exciting methods based on the extensive authors endeavors over the last five years. The objects of interest are diverse. They include carbon, boron nitride and other inorganic one- and two-dimensional nanoscale materials, e.g., nanotubes, nanowires and nanosheets. The key point of all experiments discussed is that the mechanical and electrical transport data are acquired on an individual nanostructure level under ultimately high spatial, temporal and energy resolution achievable in TEM, and thus can directly be linked to morphological, structural and chemical peculiarities of a given nanomaterial. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Scanning and transmission electron microscope study of pellicle morphogenesis.

    Science.gov (United States)

    Lie, T

    1977-05-01

    The morphology of pellicle formation was studied using correlated transmission and scanning electron microscopy. Pellicle developed on hydroxyapatite/epoxy resin splints attached to the buccal surfaces of molars and premolars in six young individuals. Splint segments were removed at intervals of 2, 4, 6, 12, 24, and 48 h. Measurements of pellicle thickness revealed that during the first 12 h considerably more material formed on the apatite surfaces than on the epoxy resin areas of the splints. This difference was equalized in 24- and 48-h specimens. Three types of pellicles could be distinguished on the basis of morphologic criteria. A globular pellicle, characterized by a consistent presence of globules of varying size and configuration, seemed to predominate in most subjects. These globules could not be mistaken for bacteria due to their dimensions, contour, and lack of cell walls. A fibrillar pellicle consisted of 3- to 7-nm-wide fibrils and frequently included some finely globular particles. A granular pellicle displayed a relatively even surface contour and did not exhibit globular or fibrillar structures. In contrast to the two other types, the granular pellicle contained distinct laminations. Apparently, the varying morphology of the early pellicle is a reflection of its complex chemical composition.

  14. Ultra high speed image processing techniques. [electronic packaging techniques

    Science.gov (United States)

    Anthony, T.; Hoeschele, D. F.; Connery, R.; Ehland, J.; Billings, J.

    1981-01-01

    Packaging techniques for ultra high speed image processing were developed. These techniques involve the development of a signal feedthrough technique through LSI/VLSI sapphire substrates. This allows the stacking of LSI/VLSI circuit substrates in a 3 dimensional package with greatly reduced length of interconnecting lines between the LSI/VLSI circuits. The reduced parasitic capacitances results in higher LSI/VLSI computational speeds at significantly reduced power consumption levels.

  15. Charging dynamics in electron transmission through Al2O3 capillaries

    DEFF Research Database (Denmark)

    Milosavljević, A.R.; Schiessl, K.; Lemell, C.

    2012-01-01

    We have measured the transmission of low-energy (E=250eV) electrons through insulating Al O nanocapillaries. We find that transmission at the incident energy is quickly suppressed with increasing tilt angle ψ of the capillary axis relative to the incoming electron beam while inelastic transmission...... becomes more important. For small angles of incidence charging dynamics lead to a decrease of total transmission (elastic and inelastic) with time. Our results are interpreted on the basis of a microscopic model for the electron transport within the capillary including also close interactions...... with the capillary wall....

  16. Electronic publications, a useful technique for astronomy outreach

    Science.gov (United States)

    Stavinschi, M.; Mosoia, C.

    2012-09-01

    Thanks to modern technology, astronomy can be communicated to the public through a variety of techniques, from classic conferences (also upgraded to the video projectors, etc.) to TV, print media and social media platforms such as Facebook, Twitter, Linkedin, MySpace, etc. We are going to present advantages of electronic publishing, starting from informing the public with latest astronomy news, to providing a place for public debate. In an era of global crisis e-publishing is a must do, be it seen from the financially perspective, or the desired impact to the public. We are going to present a constant example of year electronic publication dedicated to promoting science and communication; also, the Science Communicators Network Interested in spreading the word of astronomy. The aim is to establish connections with all OEP participants with a view to know each other and try to work in common for the better message transmission to the public. Together, we might build a single platform with multiple educational results.

  17. Directly Observing Micelle Fusion and Growth in Solution by Liquid-Cell Transmission Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Parent, Lucas R. [Department; amp, Biochemistry, University of California, San Diego, La Jolla, California 92093, United States; Bakalis, Evangelos [Dipartimento; Ramírez-Hernández, Abelardo [Materials; Institute; Kammeyer, Jacquelin K. [Department; amp, Biochemistry, University of California, San Diego, La Jolla, California 92093, United States; Park, Chiwoo [Department; de Pablo, Juan [Materials; Institute; Zerbetto, Francesco [Dipartimento; Patterson, Joseph P. [Department; amp, Biochemistry, University of California, San Diego, La Jolla, California 92093, United States; Laboratory; Gianneschi, Nathan C. [Department; amp, Biochemistry, University of California, San Diego, La Jolla, California 92093, United States

    2017-11-16

    Amphiphilic small molecules and polymers form commonplace nanoscale macromolecular compartments and bilayers, and as such are truly essential components in all cells and in many cellular processes. The nature of these architectures, including their formation, phase changes, and stimuli-response behaviors, is necessary for the most basic functions of life, and over the past half-century, these natural micellar structures have inspired a vast diversity of industrial products, from biomedicines to detergents, lubricants, and coatings. The importance of these materials and their ubiquity have made them the subject of intense investigation regarding their nanoscale dynamics with increasing interest in obtaining sufficient temporal and spatial resolution to directly observe nanoscale processes. However, the vast majority of experimental methods involve either bulk-averaging techniques including light, neutron, and X-ray scattering, or are static in nature including even the most advanced cryogenic transmission electron microscopy techniques. Here, we employ in situ liquid-cell transmission electron microscopy (LCTEM) to directly observe the evolution of individual amphiphilic block copolymer micellar nanoparticles in solution, in real time with nanometer spatial resolution. These observations, made on a proof-of-concept bioconjugate polymer amphiphile, revealed growth and evolution occurring by unimer addition processes and by particle-particle collision-and-fusion events. The experimental approach, combining direct LCTEM observation, quantitative analysis of LCTEM data, and correlated in silico simulations, provides a unique view of solvated soft matter nanoassemblies as they morph and evolve in time and space, enabling us to capture these phenomena in solution.

  18. Big Data Analytics for Scanning Transmission Electron Microscopy Ptychography.

    Science.gov (United States)

    Jesse, S; Chi, M; Belianinov, A; Beekman, C; Kalinin, S V; Borisevich, A Y; Lupini, A R

    2016-05-23

    Electron microscopy is undergoing a transition; from the model of producing only a few micrographs, through the current state where many images and spectra can be digitally recorded, to a new mode where very large volumes of data (movies, ptychographic and multi-dimensional series) can be rapidly obtained. Here, we discuss the application of so-called "big-data" methods to high dimensional microscopy data, using unsupervised multivariate statistical techniques, in order to explore salient image features in a specific example of BiFeO3 domains. Remarkably, k-means clustering reveals domain differentiation despite the fact that the algorithm is purely statistical in nature and does not require any prior information regarding the material, any coexisting phases, or any differentiating structures. While this is a somewhat trivial case, this example signifies the extraction of useful physical and structural information without any prior bias regarding the sample or the instrumental modality. Further interpretation of these types of results may still require human intervention. However, the open nature of this algorithm and its wide availability, enable broad collaborations and exploratory work necessary to enable efficient data analysis in electron microscopy.

  19. Development of a nanoindenter for in-situ transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Stach, Eric A.; Freeman, Tony; Minor, Andrew M.; Owen, Doug K.; Cumings, John; Wall, Mark A.; Chraska, Tomas; Hull, Robert; Morris Jr., J.W.; Zettl, A.; Dahmen, Ulrich

    2001-01-30

    In-situ transmission electron microscopy is an established experimental technique that permits direct observation of the dynamics and mechanisms of dislocation motion and deformation behavior. In this paper, we detail the development of a novel specimen goniometer that allows real time observations of the mechanical response of materials to indentation loads. The technology of the scanning tunneling microscope is adopted to allow nanometer scale positioning of a sharp, conductive diamond tip onto the edge of an electron transparent sample. This allows application of loads to nanometer-scale material volumes couple with simultaneous imaging of the material response. The emphasis in this paper is experimental and descriptive, with particular attention given to sample geometry and other technical requirements. Examples of the deformation of aluminum and titanium carbide as well as the fracture of silicon will be presented.

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

    Science.gov (United States)

    Barthel, J; Thust, A

    2013-11-01

    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. © 2013 Elsevier B.V. All rights reserved.

  1. The use of transmission electron microscopy in the quantification of nanoparticle dose

    International Nuclear Information System (INIS)

    Hondow, N; Brydson, R; Brown, A

    2014-01-01

    There are an increasing number of potential applications for nanoparticles in clinical medicine, including targeted drug delivery and contrast agents for biomedical imaging. Current in vitro studies are concerned with the biological impact of nanoparticles, with electron microscopy commonly employed to image their intracellular location. It is critical to quantify the absolute nanoparticle dose internalized by cells in a given exposure, and to understand the factors which affect this. In this work we are aiming to develop a full quantitative description of quantum dot uptake by an in vitro cell line. Transmission electron microscopy of thin cell sections provides the location and number of cellular vesicles per 2-D cell slice plus the number of quantum dots per vesicle. These results can then be correlated to other techniques to quantify the internalized nanoparticle dose distribution for whole cells

  2. Chemical mapping and quantification at the atomic scale by scanning transmission electron microscopy.

    Science.gov (United States)

    Chu, Ming-Wen; Chen, Cheng Hsuan

    2013-06-25

    With innovative modern material-growth methods, a broad spectrum of fascinating materials with reduced dimensions-ranging from single-atom catalysts, nanoplasmonic and nanophotonic materials to two-dimensional heterostructural interfaces-is continually emerging and extending the new frontiers of materials research. A persistent central challenge in this grand scientific context has been the detailed characterization of the individual objects in these materials with the highest spatial resolution, a problem prompting the need for experimental techniques that integrate both microscopic and spectroscopic capabilities. To date, several representative microscopy-spectroscopy combinations have become available, such as scanning tunneling microscopy, tip-enhanced scanning optical microscopy, atom probe tomography, scanning transmission X-ray microscopy, and scanning transmission electron microscopy (STEM). Among these tools, STEM boasts unique chemical and electronic sensitivity at unparalleled resolution. In this Perspective, we elucidate the advances in STEM and chemical mapping applications at the atomic scale by energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy with a focus on the ultimate challenge of chemical quantification with atomic accuracy.

  3. Structural analysis of nano structured carbon by transmission electron microscopy and image processing

    Energy Technology Data Exchange (ETDEWEB)

    Oshida, K., E-mail: oshida@nagano-nct.ac.jp [Nagano National College of Technology, Nagano 381-8550 (Japan); Murata, M.; Fujiwara, K.; Itaya, T. [Nagano National College of Technology, Nagano 381-8550 (Japan); Yanagisawa, T.; Kimura, K. [GSI Creos Corporation, Kanagawa 210-0855 (Japan); Nakazawa, T.; Kim, Y.A.; Endo, M. [Shinshu University, Nagano 380-8553 (Japan); Kim, B.-H.; Yang, K.S. [Chonnam National University, Gwangju 500-757 (Korea, Republic of)

    2013-06-15

    Transmission electron microscopy (TEM) is one of the highest resolution analysis methods of materials. The three dimensional recognition of the materials is difficult by TEM because the observation data is projection images through the materials. In this study, space structure of carbon nanotubes loaded with metal particles was analyzed by three dimensional TEM (3D-TEM) [1,2]. The nano structured carbons are also observed by high resolution transmission electron microscopy (HRTEM) with Cs corrector. Cup-stack type carbon nanotubes (CSCNTs) loaded with Pt particles (2–3 nm in diameter) prepared by GSI Creos Corporation were analyzed by these methods. Pt particles are bound selectively to the edges of hexagonal carbon layers of inside and outer surface of CSCNTs efficiently and can be expected to work well as catalysts of electrodes of fuel cell. It is sometimes difficult that the nano sized area is analyzed by selected area electron diffraction (SAD) because the selected area aperture cannot be so small. The HRTEM and image processing technique give similar results of SAD when it works and revealed to be useful to analyze nano structured carbons.

  4. 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

  5. Transmission Electron Microscopy of Iron Metal in Almahata Sitta Ureilite

    Science.gov (United States)

    Mikouchi, T.; Yubuta, K.; Sugiyama, K.; Aoyagi, Y.; Yasuhara, A.; Mihira, T.; Zolensky, M. E.; Goodrich, C. A.

    2013-01-01

    Almahata Sitta (AS) is a polymict breccia mainly composed of variable ureilite lithologies with small amounts of chondritic lithologies [1]. Fe metal is a common accessory phase in ureilites, but our earlier study on Fe metals in one of AS fragments (#44) revealed a unique mineralogy never seen in other ureilites [2,3]. In this abstract we report detailed transmission electron microscopy (TEM) on these metal grains to better understand the thermal history of ureilites. We prepared FIB sections of AS#44 by JEOL JIB-4000 from the PTS that was well characterized by SEM-EBSD in our earlier study [2]. The sections were then observed by STEM (JEOL JEM- 2100F). One of the FIB sections shows a submicron-sized symplectic intergrown texture composed of Fe metal (kamacite), Fe carbide (cohenite), Fe phosphide (schreibersite), and Fe sulfide (troilite). Each phase has an identical SAED pattern in spite of its complex texture, suggesting co-crystallization of all phases. This is probably caused by shock re-melting of pre-existing metal + graphite to form a eutectic-looking texture. The other FIB section is mostly composed of homogeneous Fe metal (93 wt% Fe, 5 wt% Ni, and 2 wt% Si), but BF-STEM images exhibited the presence of elongated lathy grains (approx. 2 microns long) embedded in the interstitial matrix. The SAED patterns from these lath grains could be indexed by alpha-Fe (bcc) while interstitial areas are gamma-Fe (fcc). The elongated alpha-Fe grains show tweed-like structures suggesting martensite transformation. Such a texture can be formed by rapid cooling from high temperature where gamma-Fe was stable. Subsequently alpha-Fe crystallized, but gamma-Fe remained in the interstitial matrix due to quenching from high temperature. This scenario is consistent with very rapid cooling history of ureilites suggested by silicate mineralogy.

  6. 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.

  7. In situ conversion of nanostructures from solid to hollow in transmission electron microscopes using electron beam.

    Science.gov (United States)

    El Mel, Abdel-Aziz; Bittencourt, Carla

    2016-06-07

    With the current development of electron beam sources, the use of transmission electron microscopes is no more limited to imaging or chemical analysis but has rather been extended to nanoengineering. This includes the e-beam induced growth, etching and structural transformation of nanomaterials. In this review we summarize recent progress on the e-beam induced morphological transformation of nanostructures from solid to hollow. We provide a detailed account of the processes reported so far in the literature with a special emphasis on the mechanistic understanding of the e-beam induced hollowing of nanomaterials. Through an important number of examples, we discuss how one can achieve a precise control of such hollowing processes by understanding the fundamental mechanisms occurring at the atomic scale during the irradiation of solid nanostructures. Finally, we conclude with remarks and our own view on the prospective future directions of this research field.

  8. 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.

  9. Picoliter Drop-On-Demand Dispensing for Multiplex Liquid Cell Transmission Electron Microscopy.

    Science.gov (United States)

    Patterson, Joseph P; Parent, Lucas R; Cantlon, Joshua; Eickhoff, Holger; Bared, Guido; Evans, James E; Gianneschi, Nathan C

    2016-06-01

    Liquid cell transmission electron microscopy (LCTEM) provides a unique insight into the dynamics of nanomaterials in solution. Controlling the addition of multiple solutions to the liquid cell remains a key hurdle in our ability to increase throughput and to study processes dependent on solution mixing including chemical reactions. Here, we report that a piezo dispensing technique allows for mixing of multiple solutions directly within the viewing area. This technique permits deposition of 50 pL droplets of various aqueous solutions onto the liquid cell window, before assembly of the cell in a fully controlled manner. This proof-of-concept study highlights the great potential of picoliter dispensing in combination with LCTEM for observing nanoparticle mixing in the solution phase and the creation of chemical gradients.

  10. Picoliter Drop-On-Demand Dispensing for Multiplex Liquid Cell Transmission Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, Joseph P.; Parent, Lucas R.; Cantlon, Joshua; Eickhoff, Holger; Bared, Guido; Evans, James E.; Gianneschi, Nathan C.

    2016-05-03

    Abstract

    Liquid cell transmission electron microscopy (LCTEM) provides a unique insight into the dynamics of nanomaterials in solution. Controlling the addition of multiple solutions to the liquid cell remains a key hurdle in our ability to increase throughput and to study processes dependent on solution mixing including chemical reactions. Here, we report that a piezo dispensing technique allows for mixing of multiple solutions directly within the viewing area. This technique permits deposition of 50 pL droplets of various aqueous solutions onto the liquid cell window, before assembly of the cell in a fully controlled manner. This proof-of-concept study highlights the great potential of picoliter dispensing in combination with LCTEM for observing nanoparticle mixing in the solution phase and the creation of chemical gradients.

  11. 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...

  12. Parallel transmission techniques in magnetic resonance imaging: experimental realization, applications and perspectives

    International Nuclear Information System (INIS)

    Ullmann, P.

    2007-06-01

    The primary objective of this work was the first experimental realization of parallel RF transmission for accelerating spatially selective excitation in magnetic resonance imaging. Furthermore, basic aspects regarding the performance of this technique were investigated, potential risks regarding the specific absorption rate (SAR) were considered and feasibility studies under application-oriented conditions as first steps towards a practical utilisation of this technique were undertaken. At first, based on the RF electronics platform of the Bruker Avance MRI systems, the technical foundations were laid to perform simultaneous transmission of individual RF waveforms on different RF channels. Another essential requirement for the realization of Parallel Excitation (PEX) was the design and construction of suitable RF transmit arrays with elements driven by separate transmit channels. In order to image the PEX results two imaging methods were implemented based on a spin-echo and a gradient-echo sequence, in which a parallel spatially selective pulse was included as an excitation pulse. In the course of this work PEX experiments were successfully performed on three different MRI systems, a 4.7 T and a 9.4 T animal system and a 3 T human scanner, using 5 different RF coil setups in total. In the last part of this work investigations regarding possible applications of Parallel Excitation were performed. A first study comprised experiments of slice-selective B1 inhomogeneity correction by using 3D-selective Parallel Excitation. The investigations were performed in a phantom as well as in a rat fixed in paraformaldehyde solution. In conjunction with these experiments a novel method of calculating RF pulses for spatially selective excitation based on a so-called Direct Calibration approach was developed, which is particularly suitable for this type of experiments. In the context of these experiments it was demonstrated how to combine the advantages of parallel transmission

  13. 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

  14. Transmission electron microscopy and time resolved optical spectroscopy study of the electronic and structural interactions of ZnO nanorods with bovine serum albumin.

    Science.gov (United States)

    Klaumünzer, M; Weichsel, U; Mačković, M; Spiecker, E; Peukert, W; Kryschi, C

    2013-08-22

    The adsorption behavior and electronic interactions of bovine serum albumin (BSA) with ZnO nanorod surfaces were investigated using high-resolution transmission electron microscopy as well as stationary and time-resolved optical spectroscopy techniques. Transmission electron microscopy shows that ZnO nanorod surfaces are surrounded by a homogeneous amorphous BSA film with thicknesses between ~2.5 and 5.0 nm. The electronic structure and adsorption geometry of BSA were examined using high-angle annular dark field scanning transmission electron microscopy combined with electron energy loss spectroscopy. The adsorption process was observed to result into an unfolded conformation of BSA becoming predominantly bound in the side-on orientation at the ZnO surface. This adsorption mode of the BSA molecules allows for a strong interaction with surface states of the ZnO nanorods. This is obvious from its efficient quenching of the defect-center photoluminescence of ZnO. Complementary information of electronic interactions across the ZnO nanorod interface was obtained from femtosecond transient absorption spectroscopy experiments. The rise dynamics of the measured transients revealed altered hole trapping dynamics and, thus, indicated to heterogeneous charge transfer as emerging from adsorbed BSA molecules to defect centers of the ZnO interface.

  15. Recent techniques used in transmission line protection: a review

    African Journals Online (AJOL)

    user

    Power Apparatus and Systems, vol.PAS-91, no.3, pp. 1235-1243. Girgis A.A., Hart D.G. and Peterson W.L., 1992. Fault location in transmission lines using two and three terminal lines, IEEE. Trans. Power Delivery, vol.7, no.1, pp. 98-107. Girgis A.A., Sallam A.A. and Karim El-Din A., 1998. An adaptive protection scheme for ...

  16. In Situ Electronic Characterization of Graphene Nanoconstrictions Fabricated in a Transmission Electron Microscope

    Science.gov (United States)

    Lu, Ye; Merchant, Christopher; Drndic, Marija; Johnson, A. T. Charlie

    2012-02-01

    We report electronic measurements on high quality graphene nanoconstrictions (GNCs) fabricated in a transmission electron microscope (TEM), and the first measurements on GNC conductance with an accurate measurement of constriction width down to 1 nm. To create the GNCs, freely suspended graphene ribbons were fabricated using few-layer graphene grown by chemical vapor deposition. The ribbons were loaded into the TEM, and a current-annealing procedure was used to clean the material and improve its electronic characteristics. The TEM beam was then used to sculpt GNCs to a series of desired widths in the range 1-700 nm; after each sculpting step, the sample was imaged by TEM and its electronic properties were measured in situ. GNC conductance was found to be remarkably high, comparable to that of exfoliated graphene samples of similar size. The GNC conductance varied with width approximately as G(w) = (e^2/h)w^0.75, where w is the constriction width in nanometers. GNCs support current densities greater than 120 μA/nm^2, 2 orders of magnitude higher than that which has been previously reported for graphene nanoribbons and 2000 times higher than that reported for copper.

  17. Microstructural characterization of porous materials by X-ray microtomography and gamma ray transmission techniques

    International Nuclear Information System (INIS)

    Moreira, Anderson Camargo

    2006-01-01

    This work presents the application of the X-ray microtomography and gamma ray transmission techniques for the microstructure characterization of different kinds of materials. Total porosity, pore size distribution and the two point correlation functions were measured. The two point correlation function, which allows the reconstruction of 3D models, was carried out for two samples. Seven ceramic tablets of Alumina (Al 2 O 3 ), seven tablets of Boron Carbide (B 4 C), three samples of sedimentary rocks and one sample of Titanium foam were analyzed. The experimental set up for the Gamma Ray Transmission technique consisted of: a 2'' x 2'' crystal NaI(Tl) detector, an 241 Am radioactive source (59,53 keV, 100 mCi), an automatic micrometric table for the sample XZ movement and standard gamma spectrometry electronics. Two microtomography systems were used: a Fein Focus system, constituted by an X-ray tube, operated at 160 kV and 0.3 to 1.1 mA, a CCD camera and the movement sample system, and a Skyscan system, model 1072, with a X-ray tube operated at 100 kV and 100μA, and a CCD camera. The ceramic tablets, analyzed by the gamma ray transmission technique presented results for most of the porosities data with smaller confidence intervals and inside the intervals supplied by the tablets manufacturer. The Titanium porous sample was analyzed by the two techniques, its microtomography images achieved a resolution of 17μm, obtained employing the Fein Focus system. For both techniques, this sample showed high porosity, which allows its application for this purpose. The sandstones samples were analyzed by the Skyscan system, achieving resolutions of 19μm, 11μm and 3.8μm for each sample, respectively. The resolutions of 11μm and 3.8μm were the ones that generated better 2D sections for the respective samples and, consequently, more reliable porosities. The 3.8μm resolution was the one that best quantified the pore size distribution data, showing information not shown by

  18. Cryogenic transmission electron microscopy nanostructural study of shed microparticles.

    Directory of Open Access Journals (Sweden)

    Liron Issman

    Full Text Available Microparticles (MPs are sub-micron membrane vesicles (100-1000 nm shed from normal and pathologic cells due to stimulation or apoptosis. MPs can be found in the peripheral blood circulation of healthy individuals, whereas elevated concentrations are found in pregnancy and in a variety of diseases. Also, MPs participate in physiological processes, e.g., coagulation, inflammation, and angiogenesis. Since their clinical properties are important, we have developed a new methodology based on nano-imaging that provides significant new data on MPs nanostructure, their composition and function. We are among the first to characterize by direct-imaging cryogenic transmitting electron microscopy (cryo-TEM the near-to-native nanostructure of MP systems isolated from different cell types and stimulation procedures. We found that there are no major differences between the MP systems we have studied, as most particles were spherical, with diameters from 200 to 400 nm. However, each MP population is very heterogeneous, showing diverse morphologies. We investigated by cryo-TEM the effects of standard techniques used to isolate and store MPs, and found that either high-g centrifugation of MPs for isolation purposes, or slow freezing to -80 °C for storage introduce morphological artifacts, which can influence MP nanostructure, and thus affect the efficiency of these particles as future diagnostic tools.

  19. Transmission electron microscopy of unstained hybrid Au nanoparticles capped with PPAA (plasma-poly-allylamine): structure and electron irradiation effects.

    Science.gov (United States)

    Gontard, Lionel C; Fernández, Asunción; Dunin-Borkowski, Rafal E; Kasama, Takeshi; Lozano-Pérez, Sergio; Lucas, Stéphane

    2014-12-01

    Hybrid (organic shell-inorganic core) nanoparticles have important applications in nanomedicine. Although the inorganic components of hybrid nanoparticles can be characterized readily using conventional transmission electron microscopy (TEM) techniques, the structural and chemical arrangement of the organic molecular components remains largely unknown. Here, we apply TEM to the physico-chemical characterization of Au nanoparticles that are coated with plasma-polymerized-allylamine, an organic compound with the formula C3H5NH2. We discuss the use of energy-filtered TEM in the low-energy-loss range as a contrast enhancement mechanism for imaging the organic shells of such particles. We also study electron-beam-induced crystallization and amorphization of the shells and the formation of graphitic-like layers that contain both C and N. The resistance of the samples to irradiation by high-energy electrons, which is relevant for optical tuning and for understanding the degree to which such hybrid nanostructures are stable in the presence of biomedical radiation, is also discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Vesicular lipidic systems, liposomes, PLO, and liposomes-PLO: characterization by electronic transmission microscopy.

    Science.gov (United States)

    Ruiz, M Adolfina; Clares, Beatriz; Morales, M Encarnacion; Gallardo, Visitacion

    2008-12-01

    Situations exist in which rapid administration of treatment, as well as maintenance of efficient concentrations for the longest possible time, turns out to be essential. In view of the previous treatment, the elaboration of liposomes, PLO (pluronic lecithin organogel), and the mixture of both is described, as well as their characterizations by electronic transmission microscopy, with the aim of finding out precisely the type of structure for both controlled release systems, its composition, size, homogeneity, and integrity. The period of study has been 90 days. Multilaminar and unilaminar vesicles smaller than 1 microm in diameter were seen in the liposomes, PLO, and liposomes-PLO formulations on transmission electron microscopic (TEM) observation. The technique of characterization reveals the progressive aggregation of the liposomas along the period of study. However, all the vesicles of PLO maintain a defined structure and only a light aggregation 60 days after the elaboration. Changes of morphology and aggregation of liposomas decreased after the incorporation of cholesterol (CH) to the liposomal matrix. The best results were obtained with the formulas liposomes-PLO, which maintain their individuality and integrity during the whole period of study. The combined formulation of liposomas and PLO showed an increase of stability of both lipid systems.

  1. Total electron content measurements at Gauhati using 140 MHz ATS-6 transmissions

    International Nuclear Information System (INIS)

    Tyagi, T.R.; Singh, L.; Minakshi Devi; Barbara, A.K.

    1977-01-01

    The amplitude and phase of 140 MHz transmissions from geostationary satellite ATS-6 (0 0 N, 35 0 E) have been recorded at Gauhati (26.16 0 N; 91.75 0 E) for the period Nov. 1975 to Aug. 1976. The calibration technique for geostationary satellite Faraday rotation measurements suggested by Checcacci and Giorgeo has been improved and generalized. It is then utilized to remove the n ambiguity in Faraday rotation values and also to estimate the correct value of diurnal minimum Faraday rotation angle so that the recorded Faraday rotation values can be converted into electron content values. Typical diurnal variation curves have been obtained for all the months except for equinoxes when the satellite transmission was off very often due to ecliptic conditions and hence no complete diurnal curves could be obtained for these months. It has been found that though December and January behave like typical winter months, the month of November is more like an equinoctial month. Similarly, though June and July behave like typical summer months, the month of May is more or less similar to equinoxes. The characteristic features of the diurnal and seasonal behaviour of the electron content have been discussed. (author)

  2. Nicotiana Occidentalis Chloroplast Ultrastructure imaged with Transmission Electron Microscopes Working at Different Accelerating Voltages

    OpenAIRE

    SVIDENSKÁ, Silvie

    2010-01-01

    The main goal of this thesis is to study and compare electron microscopy images of Nicotiana Occidentalis chloroplasts, obtained from two types of transmission electron microscopes,which work with different accelerating voltage of 80kV and 5kV. The two instruments, TEM JEOL 1010 and low voltage electron microscope LVEM5 are employed for experiments. In the first theoretical part, principle of electron microscopy and chloroplast morphology is described. In experimental part, electron microscop...

  3. 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.

  4. Practical spatial resolution of electron energy loss spectroscopy in aberration corrected scanning transmission electron microscopy.

    Science.gov (United States)

    Shah, A B; Ramasse, Q M; Wen, J G; Bhattacharya, A; Zuo, J M

    2011-08-01

    The resolution of electron energy loss spectroscopy (EELS) is limited by delocalization of inelastic electron scattering rather than probe size in an aberration corrected scanning transmission electron microscope (STEM). In this study, we present an experimental quantification of EELS spatial resolution using chemically modulated 2×(LaMnO(3))/2×(SrTiO(3)) and 2×(SrVO(3))/2×(SrTiO(3)) superlattices by measuring the full width at half maxima (FWHM) of integrated Ti M(2,3), Ti L(2,3), V L(2,3), Mn L(2,3), La N(4,5), La N(2,3) La M(4,5) and Sr L(3) edges over the superlattices. The EELS signals recorded using large collection angles are peaked at atomic columns. The FWHM of the EELS profile, obtained by curve-fitting, reveals a systematic trend with the energy loss for the Ti, V, and Mn edges. However, the experimental FWHM of the Sr and La edges deviates significantly from the observed experimental tendency. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Unravelling surface and interfacial structures of a metal–organic framework by transmission electron microscopy

    KAUST Repository

    Zhu, Yihan

    2017-02-21

    Metal–organic frameworks (MOFs) are crystalline porous materials with designable topology, porosity and functionality, having promising applications in gas storage and separation, ion conduction and catalysis1, 2, 3. It is challenging to observe MOFs with transmission electron microscopy (TEM) due to the extreme instability of MOFs upon electron beam irradiation4, 5, 6, 7. Here, we use a direct-detection electron-counting camera to acquire TEM images of the MOF ZIF-8 with an ultralow dose of 4.1 electrons per square ångström to retain the structural integrity. The obtained image involves structural information transferred up to 2.1 Å, allowing the resolution of individual atomic columns of Zn and organic linkers in the framework. Furthermore, TEM reveals important local structural features of ZIF-8 crystals that cannot be identified by diffraction techniques, including armchair-type surface terminations and coherent interfaces between assembled crystals. These observations allow us to understand how ZIF-8 crystals self-assemble and the subsequent influence of interfacial cavities on mass transport of guest molecules.

  6. Environmental transmission electron microscopy for catalyst materials using a spherical aberration corrector.

    Science.gov (United States)

    Takeda, Seiji; Kuwauchi, Yasufumi; Yoshida, Hideto

    2015-04-01

    Atomic resolution has been obtained using environmental transmission electron microscopy (ETEM) by installing a spherical aberration corrector (Cs-corrector) on the objective lens. Simultaneously, the technology for controlling the environment around a specimen in ETEM has advanced significantly in the past decade. Quantification methodology has recently been established for deriving relevant experimental data in catalyst materials from substantial and systematic ETEM observation at the atomic scale. With this background, this paper summarizes aspects of the evolutional microscopy technique: necessary conditions for atomic resolution in ETEM; reduction of the scattering of electrons by the medium surrounding a specimen; and an environmental cell for structural imaging of a crystalline specimen. The high spatial resolution of a Cs-corrected ETEM is demonstrated for different observation conditions. After statistical analysis combined with numerical image analysis of ETEM data is briefly described, the recent applications of the Cs-corrected ETEM to catalyst materials are reviewed. For gold nanoparticulate catalysts, the structural information on the reaction sites and adsorption sites are deduced. For Pt nanoparticulate catalysts, ETEM studies elucidate the correlation between the catalytic activity and the morphology of the nanoparticles. These studies also reveal oxidation and reduction on the topmost Pt surface layer at the atomic scale. Finally, current issues and the future perspectives of Cs-corrected ETEM are summarized, including the reproducibility of ETEM observation data, the control of environments, the critical evaluation of electron irradiation effects, the full implementation of transmission electron microscopy technology in ETEM, and the safety issues for an ETEM laboratory. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Measurement to the spatial distribution of scattered electrons in transmission and reflexion with an electron emission microscope

    International Nuclear Information System (INIS)

    Hasselbach, F.

    1973-01-01

    The broadening of a narrow, approximately parallel electron beam of 19.5 keV energy when penetrating thin foils and as a result, respectively, of backscattering from the surfaces of solids is measured by imaging the secondary electrons in the emission microscope. For this purpose, a special electron emission microscope was built in which the foil to be penetrated with its various thicknesses acted as a cathode of the emission microscope. For the measurement carried out by the transmission technique, an electron beam was reduced to some 4,000 A by two magnetic lenses and by the deceleration field of the cathode lens, which decreased the impact energy of the electrons on the foil to 19.5 keV. The beam impinges perpendicularly upon the foil to be penetrated. In the case of backscattering the beam generation system is attached to the side of the emission microscope in such a way that the beam impinges upon the surface under an angle of approximately 10 0 . In both cases, deflection systems permit scanning of the object. Both photographic plates and solid state devices were used for recording. The results obtained in this way from the penetration of aluminum as a representative of an element with a low and of germanium as an element with an intermediate atomic number agree with the scattering theory in the area of multiple scattering, with is based on Boltzmann's transport equation. This equation was used for multiple scattering for the first time by Fermi in 1940, later on also by F. Lenz. The results obtained for reflexion from Al, Au and KCl clearly show broadening. (orig./RF) [de

  8. Statistics techniques applied to electron probe microanalysis

    International Nuclear Information System (INIS)

    Brizuela, H.; Del Giorgio, M.; Budde, C.; Briozzo, C.; Riveros, J.

    1987-01-01

    A description of Montroll-West's general theory for a tridimensional random walk of a particle with internal degrees of freedom is given, connecting this problem with the master equation solution. The possibility of its application to EPMA is discussed. Numerical solutions are given for thick or collimated beams at several energies interacting with samples of different shape and size. Spatial distribution of particles within the sample -for a stationary state- is analized, as well as the electron backscattering coefficient. (Author) [es

  9. Comparison of the decameric structure of peroxiredoxin-II by transmission electron microscopy and X-ray crystallography

    DEFF Research Database (Denmark)

    Harris, J. Robin; Schröder, Ewald; Isupov, Michail N.

    2001-01-01

    Peroxiredoxin; Transmission electron microscopy; X-ray structure; Negative staining; angular reconstitution; Molecular fitting......Peroxiredoxin; Transmission electron microscopy; X-ray structure; Negative staining; angular reconstitution; Molecular fitting...

  10. Enhanced thermal stability of a polymer solar cell blend induced by electron beam irradiation in the transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Bäcke, Olof, E-mail: obacke@chalmers.se [Department of Applied Physics, Chalmers University of Technology, 41296 Göteborg (Sweden); Lindqvist, Camilla; Diaz de Zerio Mendaza, Amaia [Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Göteborg (Sweden); Gustafsson, Stefan [Department of Applied Physics, Chalmers University of Technology, 41296 Göteborg (Sweden); Wang, Ergang; Andersson, Mats R.; Müller, Christian [Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Göteborg (Sweden); Kristiansen, Per Magnus [Institute of Polymer Nanotechnology (INKA), FHNW University of Applied Science and Arts Northwestern Switzerland, 5210 Windisch (Switzerland); Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, 5232 Villigen (Switzerland); Olsson, Eva, E-mail: eva.olsson@chalmers.se [Department of Applied Physics, Chalmers University of Technology, 41296 Göteborg (Sweden)

    2017-05-15

    We show by in situ microscopy that the effects of electron beam irradiation during transmission electron microscopy can be used to lock microstructural features and enhance the structural thermal stability of a nanostructured polymer:fullerene blend. Polymer:fullerene bulk-heterojunction thin films show great promise for use as active layers in organic solar cells but their low thermal stability is a hindrance. Lack of thermal stability complicates manufacturing and influences the lifetime of devices. To investigate how electron irradiation affects the thermal stability of polymer:fullerene films, a model bulk-heterojunction film based on a thiophene-quinoxaline copolymer and a fullerene derivative was heat-treated in-situ in a transmission electron microscope. In areas of the film that exposed to the electron beam the nanostructure of the film remained stable, while the nanostructure in areas not exposed to the electron beam underwent large phase separation and nucleation of fullerene crystals. UV–vis spectroscopy shows that the polymer:fullerene films are stable for electron doses up to 2000 kGy. - Highlights: • Thermal stability of a polymer: fullerne blend is increased using electron irradiation. • Using in-situ transmission electron microscopy the nanostructure is studied. • Electron irradiation stops phase separation between the polymer and fullerene. • Electron irradiation quenches the formation and nucleation of fullerene crystals.

  11. Comparison of three techniques for skin total irradiation with electrons

    International Nuclear Information System (INIS)

    Batista, Delano V.S.; Bardella, Lucia H.; Rosa, Luiz A.R. da

    2011-01-01

    This paper compared three techniques of skin total irradiation with electrons: 1) horizontal positioning, 2) vertical positioning - rotatory technique and 3) vertical positioning - six fields technique. For that, a anthropomorphic phantom was positioned according to the recommendation for each technique and was i radiated at the linear accelerator by using the 6 MeV electrons. Radiochromic films were positioned on the surface in various regions of the phantom for measurement of absorbed dose. A ionization chamber was positioned inside of equivalent issue plates for dose evaluation due to the photons produced by electron stopping. The technique 2 and 3 have shown too similar in the results and number or discrepant points (8 and 10 respectively) of prescription lower than the technique 1 (22 points). The total body dose of photons of the 1, 2 and 3 techniques was 2.2%, 5.3% and 5.2% respectively

  12. D-stem: a parallel electron diffraction technique applied to nanomaterials.

    Science.gov (United States)

    Ganesh, K J; Kawasaki, M; Zhou, J P; Ferreira, P J

    2010-10-01

    An electron diffraction technique called D-STEM has been developed in a transmission electron microscopy/scanning transmission electron microscopy (TEM/STEM) instrument to obtain spot electron diffraction patterns from nanostructures, as small as ∼3 nm. The electron ray path achieved by configuring the pre- and postspecimen illumination lenses enables the formation of a 1-2 nm near-parallel probe, which is used to obtain bright-field/dark-field STEM images. Under these conditions, the beam can be controlled and accurately positioned on the STEM image, at the nanostructure of interest, while sharp spot diffraction patterns can be simultaneously recorded on the charge-coupled device camera. When integrated with softwares such as GatanTM STEM diffraction imaging and Automated Crystallography for TEM or DigistarTM, NanoMEGAS, the D-STEM technique is very powerful for obtaining automated orientation and phase maps based on diffraction information acquired on a pixel by pixel basis. The versatility of the D-STEM technique is demonstrated by applying this technique to nanoparticles, nanowires, and nano interconnect structures.

  13. Measurement of Local Si-Nanowire Growth Kinetics Using In situ Transmission Electron Microscopy of Heated Cantilevers

    DEFF Research Database (Denmark)

    Kallesøe, Christian; Wen, Cheng-Yen; Mølhave, Kristian

    2010-01-01

    A technique to study nanowire growth processes on locally heated microcantilevers in situ in a transmission electron microscope has been developed. The in situ observations allow the characterization of the nucleation process of silicon wires, as well as the measurement of growth rates of individ...... to calibrate the cantilever-heater parameters used in finite-element models of cantilever heating profiles, useful for optimization of the design of devices requiring local growth....

  14. Electron beam instrumentation techniques using coherent radiation

    International Nuclear Information System (INIS)

    Wang, D.X.

    1997-01-01

    Much progress has been made on coherent radiation research since coherent synchrotron radiation was first observed in 1989. The use of coherent radiation as a bunch length diagnostic tool has been studied by several groups. In this paper, brief introductions to coherent radiation and far-infrared measurement are given, the progress and status of their beam diagnostic application are reviewed, different techniques are described, and their advantages and limitations are discussed

  15. Transmission of electrons through insulating PET foils: Dependence on charge deposition, tilt angle and incident energy

    Energy Technology Data Exchange (ETDEWEB)

    Keerthisinghe, D., E-mail: darshika.keerthisinghe@wmich.edu [Department of Physics, Western Michigan University, Kalamazoo, MI 49008 (United States); Dassanayake, B.S. [Department of Physics, University of Peradeniya, Peradeniya (Sri Lanka); Wickramarachchi, S.J. [Department of Physics, Western Michigan University, Kalamazoo, MI 49008 (United States); Stolterfoht, N. [Helmholtz-Zentrum Berlin für Materialien und Energie, D-14109 Berlin (Germany); Tanis, J.A. [Department of Physics, Western Michigan University, Kalamazoo, MI 49008 (United States)

    2016-09-01

    Transmission of electrons through insulating polyethylene terephthalate (PET) nanocapillaries was observed as a function of charge deposition, angular and energy dependence. Two samples with capillary diameters 100 and 200 nm and pore densities 5 × 10{sup 8}/cm{sup 2} and 5 × 10{sup 7}/cm{sup 2}, respectively, were studied for incident electron energies of 300, 500 and 800 eV. Transmission and steady state of the electrons were attained after a time delay during which only a few electron counts were observed. The transmission through the capillaries depended on the tilt angle with both elastic and inelastic electrons going through. The guiding ability of electrons was found to increase with the incident energy in contrast to previous measurements in our laboratory for a similar PET foil.

  16. Methods to assess autophagy in situ--transmission electron microscopy versus immunohistochemistry.

    Science.gov (United States)

    Martinet, Wim; Timmermans, Jean-Pierre; De Meyer, Guido R Y

    2014-01-01

    Autophagy is a well-conserved lysosomal degradation pathway that plays a major role in both oncogenesis and tumor progression. Transmission electron microscopy (TEM) as well as immunohistochemistry are indispensable tools for the evaluation of autophagy in situ. Here, we describe an optimized protocol for the study of autophagic vacuoles by TEM and elaborate on the immunohistochemical detection of microtubule-associated protein 1 light chain (MAP1LC3, best known as LC3), which is currently considered as one of the most reliable markers of the autophagic process. The advantages, potential pitfalls, and limitations of these methods, as well as their value in the field of autophagy and oncometabolism research are discussed. Overall, we recommend a combined use of different techniques including TEM, immunohistochemistry, and molecular approaches (such as immunoblotting) for the unambiguous detection of autophagy in malignant as well as in normal tissues. © 2014 Elsevier Inc. All rights reserved.

  17. Dynamics of soft Nanomaterials captured by transmission electron microscopy in liquid water

    Energy Technology Data Exchange (ETDEWEB)

    Proetto, Maria T.; Rush, Anthony M.; Chien, Miao-Ping; Abellan Baeza, Patricia; Patterson, Joseph P.; Thompson, Matthew P.; Olson, Norman H.; Moore, Curtis E.; Rheingold, Arnold L.; Andolina, Christopher; Millstone, Jill; Howell, Stephen B.; Browning, Nigel D.; Evans, James E.; Gianneschi, Nathan C.

    2014-01-14

    In this paper we present in situ transmission electron microscopy (TEM) of soft, synthetic nanoparticles with a comparative analysis using conventional TEM methods. This comparison is made with the simple aim of describing what is an unprecedented example of in situ imaging by TEM. However, we contend the technique will quickly become essential in the characterization of analogous systems, especially where dynamics are of interest in the solvated state. In this case, particles were studied which were obtained from the direct polymerization of an oxaliplatin analog, designed for an ongoing program in novel chemotherapeutic delivery systems. The resulting nanoparticles provided sufficient contrast for facile imaging in situ, and point toward key design parameters that enable this new characterization approach for organic nanomaterials. We describe the preparation of the synthetic micellar nanoparticles to- gether with their characterization in liquid water.

  18. Microtubules in Plant Cells: Strategies and Methods for Immunofluorescence, Transmission Electron Microscopy, and Live Cell Imaging.

    Science.gov (United States)

    Celler, Katherine; Fujita, Miki; Kawamura, Eiko; Ambrose, Chris; Herburger, Klaus; Holzinger, Andreas; Wasteneys, Geoffrey O

    2016-01-01

    Microtubules (MTs) are required throughout plant development for a wide variety of processes, and different strategies have evolved to visualize and analyze them. This chapter provides specific methods that can be used to analyze microtubule organization and dynamic properties in plant systems and summarizes the advantages and limitations for each technique. We outline basic methods for preparing samples for immunofluorescence labeling, including an enzyme-based permeabilization method, and a freeze-shattering method, which generates microfractures in the cell wall to provide antibodies access to cells in cuticle-laden aerial organs such as leaves. We discuss current options for live cell imaging of MTs with fluorescently tagged proteins (FPs), and provide chemical fixation, high-pressure freezing/freeze substitution, and post-fixation staining protocols for preserving MTs for transmission electron microscopy and tomography.

  19. Application of transmission electron microscopy for microstructural characterization of perfluoropentacene thin films

    International Nuclear Information System (INIS)

    Haas, Benedikt; Beyer, Andreas; Witte, Wiebke; Breuer, Tobias; Witte, Gregor; Volz, Kerstin

    2011-01-01

    The crystalline structure and orientation of perfluoropentacene (C 22 F 14 , PFP) fibers formed upon thin-film deposition onto SiO 2 substrates have been studied by means of transmission electron microscopy (TEM), atomic force microscopy (AFM), and x-ray diffraction. The synopsis of TEM micrographs and diffraction patterns enhances the understanding of local crystal orientation on small length scales. The relationship of the PFP fiber morphology with the crystalline arrangement of PFP molecules within single fibers was established using this technique. Radiation damage, which is a critical problem for TEM investigations of organic materials, is described and the sample morphology after TEM investigations is correlated with AFM measurements of samples previously examined by TEM.

  20. A Comparative Analysis of Transmission Control Protocol Improvement Techniques over Space-Based Transmission Media

    National Research Council Canada - National Science Library

    Lawson, Joseph M

    2006-01-01

    The purpose of this study was to assess the throughput improvement afforded by the various TCP optimization techniques, with respect to a simulated geosynchronous satellite system, to provide a cost...

  1. In situ transmission electron microscopy of light-induced photocatalytic reactions

    DEFF Research Database (Denmark)

    Cavalca, Filippo; Laursen, Anders Bo; Kardynal, Beata

    2012-01-01

    Transmission electron microscopy (TEM) makes it possible to obtain insight into the structure, composition and reactivity of photocatalysts, which are of fundamental interest for sustainable energy research. Such insight can be used for further material optimization. Here, we combine conventional...

  2. In vivo degradation of processed dermal sheep collagen evaluated with transmission electron microscopy

    NARCIS (Netherlands)

    van Wachem, P.B.; van Luyn, M.J.A.; Nieuwenhuis, P.; Koerten, H.K.; Olde damink, L.H.H.; Olde-Damink, L.; ten Hoopen, Hermina W.M.; Feijen, Jan

    1991-01-01

    The in vivo degradation of hexamethylenediisocyanate-tanned dermal sheep collagen was studied with transmission electron microscopy. Discs of hexamethylenediisocyanate-tanned dermal sheep collagen were subcutaneously implanted in rats. Both an intra- and an extracellular route of degradation could

  3. INVIVO DEGRADATION OF PROCESSED DERMAL SHEEP COLLAGEN EVALUATED WITH TRANSMISSION ELECTRON-MICROSCOPY

    NARCIS (Netherlands)

    VANWACHEM, PB; VANLUYN, MJA; NIEUWENHUIS, P; KOERTEN, HK; DAMINK, LO; TENHOOPEN, H; FEIJEN, J

    The in vivo degradation of hexamethylenediisocyanate-tanned dermal sheep collagen was studied with transmission electron microscopy. Discs of hexamethylenediisocyanate-tanned dermal sheep collagen were subcutaneously implanted in rats. Both an intra- and an extracellular route of degradation could

  4. Transmission Electron Microscopy Study of Individual Carbon Nanotube Breakdown Caused by Joule Heating in Air

    DEFF Research Database (Denmark)

    Mølhave, Kristian; Gudnason, S.B.; Pedersen, Anders Tegtmeier

    2006-01-01

    We present repeated structural and electrical measurements on individual multiwalled carbon nanotubes, alternating between electrical measurements under ambient conditions and transmission electron microscopy (TEM). The multiwalled carbon nanotubes made by chemical vapor deposition were manipulated...

  5. Automated magnification calibration in transmission electron microscopy using Fourier analysis of replica images.

    NARCIS (Netherlands)

    Laak, J.A.W.M. van der; Dijkman, H.B.P.M.; Pahlplatz, M.M.M.

    2006-01-01

    The magnification factor in transmission electron microscopy is not very precise, hampering for instance quantitative analysis of specimens. Calibration of the magnification is usually performed interactively using replica specimens, containing line or grating patterns with known spacing. In the

  6. TISSUE INTERACTIONS WITH DERMAL SHEEP COLLAGEN IMPLANTS - A TRANSMISSION ELECTRON-MICROSCOPIC EVALUATION

    NARCIS (Netherlands)

    VANWACHEM, PB; VANLUYN, MJA; DAMINK, LO; FEIJEN, J; NIEUWENHUIS, P

    1991-01-01

    Tissue interactions with discs of dermal sheep collagen (DSC), subcutaneously implanted in rats, were evaluated using transmission electron microscopy. DSC cross-linked with hexamethylenediisocyanate (HDSC) had already been tested previously. In the present study, we compared tissue interactions of

  7. Aberration corrected and monochromated environmental transmission electron microscopy: challenges and prospects for materials science

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; Wagner, Jakob Birkedal; Dunin-Borkowski, Rafal E.

    2010-01-01

    The latest generation of environmental transmission electron microscopes incorporates aberration correctors and monochromators, allowing studies of chemical reactions and growth processes with improved spatial resolution and spectral sensitivity. Here, we describe the performance of such an instr...

  8. Transmission Electron Microscopy Studies of Electron-Selective Titanium Oxide Contacts in Silicon Solar Cells

    KAUST Repository

    Ali, Haider

    2017-08-15

    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 21.6% obtained on n-type cells, featuring SiO2/TiO2/Al rear contacts and after forming gas annealing (FGA) at 350°C, is due to strong surface passivation of SiO2/TiO2 stack as well as low contact resistivity at the Si/SiO2/TiO2 heterojunction. This can be attributed to the transformation of amorphous TiO2 to a conducting TiO2-x phase. Conversely, the low efficiency (9.8%) obtained on cells featuring an a-Si:H/TiO2/Al rear contact is due to severe degradation of passivation of the a-Si:H upon FGA.

  9. Catalysts under Controlled Atmospheres in the Transmission Electron Microscope

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; Wagner, Jakob Birkedal

    2014-01-01

    microscope, and since its invention by Ernst Ruska, the idea of imaging samples under gaseous atmospheres was envisioned. However, microscopes have traditionally been operated in high vacuum due to sensitive electron sources, sample contamination, and electron scattering off gas molecules resulting in loss...

  10. Advanced scanning transmission stereo electron microscopy of structural and functional engineering materials

    International Nuclear Information System (INIS)

    Agudo Jácome, L.; Eggeler, G.; Dlouhý, A.

    2012-01-01

    Stereo transmission electron microscopy (TEM) provides a 3D impression of the microstructure in a thin TEM foil. It allows to perform depth and TEM foil thickness measurements and to decide whether a microstructural feature lies inside of a thin foil or on its surface. It allows appreciating the true three-dimensional nature of dislocation configurations. In the present study we first review some basic elements of classical stereo TEM. We then show how the method can be extended by working in the scanning transmission electron microscope (STEM) mode of a modern analytical 200 kV TEM equipped with a field emission gun (FEG TEM) and a high angle annular dark field (HAADF) detector. We combine two micrographs of a stereo pair into one anaglyph. When viewed with special colored glasses the anaglyph provides a direct and realistic 3D impression of the microstructure. Three examples are provided which demonstrate the potential of this extended stereo TEM technique: a single crystal Ni-base superalloy, a 9% Chromium tempered martensite ferritic steel and a NiTi shape memory alloy. We consider the effect of camera length, show how foil thicknesses can be measured, and discuss the depth of focus and surface effects. -- Highlights: ► The advanced STEM/HAADF diffraction contrast is extended to 3D stereo-imaging. ► The advantages of the new technique over stereo-imaging in CTEM are demonstrated. ► The new method allows foil thickness measurements in a broad range of conditions. ► We show that features associated with ion milling surface damage can be beneficial for appreciating 3D features of the microstructure.

  11. 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

  12. 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

  13. Elucidation of crystal and electronic structures within highly strained BiFeO3 by transmission electron microscopy and first-principles simulation

    OpenAIRE

    Bae, In-Tae; Kov?cs, Andr?s; Zhao, Hong Jian; ??iguez, Jorge; Yasui, Shintaro; Ichinose, Tomohiro; Naganuma, Hiroshi

    2017-01-01

    Crystal and electronic structures of ~380?nm BiFeO3 film grown on LaAlO3 substrate are comprehensively studied using advanced transmission electron microscopy (TEM) technique combined with first-principles theory. Cross-sectional TEM images reveal the BiFeO3 film consists of two zones with different crystal structures. While zone II turns out to have rhombohedral BiFeO3, the crystal structure of zone I matches none of BiFeO3 phases reported experimentally or predicted theoretically. Detailed ...

  14. 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

  15. Application-level technique for faster transmission of large images on the internet

    Science.gov (United States)

    Long, L. Rodney; Berman, Lewis E.; Neve, Leif; Roy, Gautam; Thoma, George R.

    1995-03-01

    An application-level technique for improving the transmission rate of large files is described in this paper. Such techniques are important in areas such as telemedicine, where near-real-time delivery of large files such as digital images is a goal: end users may include specialist whose time is scarce and expensive, and timely access to the data may be necessary for effective clinical treatment. Faster delivery is also an enabling technology for accessing remote medial archives. In conventional TCP/IP transmission, data to be transmitted is sent down one logical communication channel. Our technique divided the data into segments; each segment is sent down its own channel, and the segments are reassembled into a copy of the original data at the receiving end. This technique has been implemented and tested in a client-server program using Berkeley Unix sockets, multiple independent process for channel control, and interprocess communication techniques to guarantee the receipt and correct reassembly of the transmitted data. Performance measurements have been made on several hundred Internet transmissions (including Arizona-to-Maryland transmissions) of 5-megabyte cervical x- ray images. Transmission time as a function of number of channels has been recorded, and a 3-fold improvement in transmission rate has been observed.

  16. Electron Beam Polarization Measurement Using Touschek Lifetime Technique

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Changchun; /Duke U., DFELL; Li, Jingyi; /Duke U., DFELL; Mikhailov, Stepan; /Duke U., DFELL; Popov, Victor; /Duke U., DFELL; Wu, Wenzhong; /Duke U., DFELL; Wu, Ying; /Duke U., DFELL; Chao, Alex; /SLAC; Xu, Hong-liang; /Hefei, NSRL; Zhang, Jian-feng; /Hefei, NSRL

    2012-08-24

    Electron beam loss due to intra-beam scattering, the Touschek effect, in a storage ring depends on the electron beam polarization. The polarization of an electron beam can be determined from the difference in the Touschek lifetime compared with an unpolarized beam. In this paper, we report on a systematic experimental procedure recently developed at Duke FEL laboratory to study the radiative polarization of a stored electron beam. Using this technique, we have successfully observed the radiative polarization build-up of an electron beam in the Duke storage ring, and determined the equilibrium degree of polarization and the time constant of the polarization build-up process.

  17. Carbon contamination in scanning transmission electron microscopy and its impact on phase-plate applications.

    Science.gov (United States)

    Hettler, Simon; Dries, Manuel; Hermann, Peter; Obermair, Martin; Gerthsen, Dagmar; Malac, Marek

    2017-05-01

    We analyze electron-beam induced carbon contamination in a transmission electron microscope. The study is performed on thin films potentially suitable as phase plates for phase-contrast transmission electron microscopy. Electron energy-loss spectroscopy and phase-plate imaging is utilized to analyze the contamination. The deposited contamination layer is identified as a graphitic carbon layer which is not prone to electrostatic charging whereas a non-conductive underlying substrate charges. Several methods that inhibit contamination are evaluated and the impact of carbon contamination on phase-plate imaging is discussed. The findings are in general interesting for scanning transmission electron microscopy applications. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  18. In SITU Transmission Electron Microscopy on Operating Electrochemical CELLS

    DEFF Research Database (Denmark)

    Gualandris, Fabrizio; Simonsen, Søren Bredmose; Mogensen, Mogens Bjerg

    2016-01-01

    Solid oxide cells (SOC) have the potential of playing a significant role in the future efficient energy system scenario. In order to become widely commercially available, an improved performance and durability of the cells has to be achieved [1]. Conventional scanning and transmission SEM and TEM...... have been often used for ex-situ post mortem characterization of SOFCs and SOECs [2,3]. However, in order to get fundamental insight of the microstructural development of SOFC/SOEC during operation conditions in situ studies are necessary [4]....

  19. Single atom image observation by means of scanning transmission electron microscope

    International Nuclear Information System (INIS)

    Komoda, Tsutomu; Todokoro, Hideo; Nomura, Setsuo

    1977-01-01

    In a scanning transmission electron microscope, electrons emitted from the ion source are finely focused to a spot on a specimen, and scanned with the deflection coil. The electrons transmitted through the specimen are detected by the scintillate, and converted to image signals with the photomultiplier, and the image is obtained on the cathode ray tube. The Hitachi scanning transmission electron microscope employs a field emission type electron gun, thus it can focus the electron beam to 0.3 nm diameter. In the microscope, elastically scattered electrons are captured by a doughnut shaped detector, while the electrons transmitted through the specimen without colliding with atoms and the non-elastically scattered electrons which has lost a part of their energy due to the ionization or excitation of atoms are detected by the energy analyzer installed at the bottom of the microscope. Though single atom image observation requires the fixation of the atoms to be marked on a support, the problem is how to discriminate the aimed atoms from the atoms of the support. The most sensitive method is the dark-field method which uses the difference of elastically scattered electron intensity as the signal. Thorium and iodine atom images have been successfully observed as the trials to prove the feasibility of observation of heavy atoms with the scanning transmission electron microscope. (Wakatsuki, Y.)

  20. Exorcising Ghost Transmission from Electron Transport Calculations: Refighting Old Battles in New Contexts

    Science.gov (United States)

    Reuter, Matthew; Harrison, Robert

    2014-03-01

    First-principles calculations of electron transport aim to understand the dynamics of electrons as they traverse quantum mechanical systems. For instance, how does electric current travel through a molecule? Despite their successes over the years, these calculations are known to be haunted by several numerical artifacts. Ghost transmission is among the most serious of these unphysical results, causing transmission coefficients to show an extreme dependence on the basis set and to be many orders of magnitude too large. In this talk, we discuss electron transport formalisms, uncover the cause of ghost transmission, develop exorcism strategies, and present several numerical examples. In the end, ghost transmission is a ramification of poorly chosen spatial partitions. Instead of choosing partitions with the basis set (in a manner reminiscent of Mulliken or Löwdin population analyses), the relevant projection operators must be selected without referencing the basis set.

  1. Selective growth and characterization of nanostructures with transmission electron microscopes

    Science.gov (United States)

    Shimojo, M.; Bysakh, S.; Mitsuishi, K.; Tanaka, M.; Song, M.; Furuya, K.

    2005-02-01

    A new type of electron beam-induced reactions is reported. Focused electron beams, the probe size of which is about 0.8 nm, were irradiated on carbon and Si substrates with an introduction of an aluminum trichloride or a gold trichloride gas in the chamber. Nanometer-sized carbon and Si rods were formed using carbon and Si substrates, respectively, by moving the beam position at a certain speed. As no aluminum, gold or chlorine was found in the rods, it is considered that chloride gases behaved as a sort of catalysis.

  2. Selective growth and characterization of nanostructures with transmission electron microscopes

    International Nuclear Information System (INIS)

    Shimojo, M.; Bysakh, S.; Mitsuishi, K.; Tanaka, M.; Song, M.; Furuya, K.

    2005-01-01

    A new type of electron beam-induced reactions is reported. Focused electron beams, the probe size of which is about 0.8 nm, were irradiated on carbon and Si substrates with an introduction of an aluminum trichloride or a gold trichloride gas in the chamber. Nanometer-sized carbon and Si rods were formed using carbon and Si substrates, respectively, by moving the beam position at a certain speed. As no aluminum, gold or chlorine was found in the rods, it is considered that chloride gases behaved as a sort of catalysis

  3. Chemical Reactions of Molecules Promoted and Simultaneously Imaged by the Electron Beam in Transmission Electron Microscopy.

    Science.gov (United States)

    Skowron, Stephen T; Chamberlain, Thomas W; Biskupek, Johannes; Kaiser, Ute; Besley, Elena; Khlobystov, Andrei N

    2017-08-15

    The main objective of this Account is to assess the challenges of transmission electron microscopy (TEM) of molecules, based on over 15 years of our work in this field, and to outline the opportunities in studying chemical reactions under the electron beam (e-beam). During TEM imaging of an individual molecule adsorbed on an atomically thin substrate, such as graphene or a carbon nanotube, the e-beam transfers kinetic energy to atoms of the molecule, displacing them from equilibrium positions. Impact of the e-beam triggers bond dissociation and various chemical reactions which can be imaged concurrently with their activation by the e-beam and can be presented as stop-frame movies. This experimental approach, which we term ChemTEM, harnesses energy transferred from the e-beam to the molecule via direct interactions with the atomic nuclei, enabling accurate predictions of bond dissociation events and control of the type and rate of chemical reactions. Elemental composition and structure of the reactant molecules as well as the operating conditions of TEM (particularly the energy of the e-beam) determine the product formed in ChemTEM processes, while the e-beam dose rate controls the reaction rate. Because the e-beam of TEM acts simultaneously as a source of energy for the reaction and as an imaging tool monitoring the same reaction, ChemTEM reveals atomic-level chemical information, such as pathways of reactions imaged for individual molecules, step-by-step and in real time; structures of illusive reaction intermediates; and direct comparison of catalytic activity of different transition metals filmed with atomic resolution. Chemical transformations in ChemTEM often lead to previously unforeseen products, demonstrating the potential of this method to become not only an analytical tool for studying reactions, but also a powerful instrument for discovery of materials that can be synthesized on preparative scale.

  4. Morphology and ultrastructure of Siberian sturgeon (Acipenser baerii) spermatozoa using scanning and transmission electron microscopy

    Czech Academy of Sciences Publication Activity Database

    Pšenička, M.; Hadi Alavi, S.M.; Rodina, M.; Gela, D.; Nebesářová, Jana; Linhart, O.

    2007-01-01

    Roč. 99, č. 2 (2007), s. 103-115 ISSN 0248-4900 R&D Projects: GA ČR GA524/06/0817 Institutional research plan: CEZ:AV0Z60220518 Keywords : acrosome * flagellum * scanning electron microscopy * Siberian sturgeon * Acipenser baerii * spermatozoon , * transmission electron microscopy Subject RIV: ED - Physiology Impact factor: 3.752, year: 2007

  5. 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.

  6. A toolkit for the characterization of CCD cameras for transmission electron microscopy

    NARCIS (Netherlands)

    Vulovic, M.; Rieger, B.; Van Vliet, L.J.; Koster, A.J.; Ravelli, R.B.G.

    2009-01-01

    Charge-coupled devices (CCD) are nowadays commonly utilized in transmission electron microscopy (TEM) for applications in life sciences. Direct access to digitized images has revolutionized the use of electron microscopy, sparking developments such as automated collection of tomographic data, focal

  7. Analysis of intermetallic particles in Mg-12 wt.%Zn binyry alloy using transmission electron microscopy

    Czech Academy of Sciences Publication Activity Database

    Němec, Martin; Gärtnerová, Viera; Klementová, Mariana; Jäger, Aleš

    2015-01-01

    Roč. 106, Aug (2015), s. 428-436 ISSN 1044-5803 R&D Projects: GA ČR GBP108/12/G043 Institutional support: RVO:68378271 Keywords : biomedical alloy s * heat treatment * microstructure * transmission electron microscopy * electron diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.383, year: 2015

  8. Anisotropic Shape Changes of Silica Nanoparticles Induced in Liquid with Scanning Transmission Electron Microscopy

    NARCIS (Netherlands)

    Zecevic, J.; Hermannsdorfer, Justus; Schuh, Tobias; de Jong, Krijn P.; de Jonge, Niels

    2017-01-01

    Liquid-phase transmission electron microscopy (TEM) is used for in-situ imaging of nanoscale processes taking place in liquid, such as the evolution of nanoparticles during synthesis or structural changes of nanomaterials in liquid environment. Here, it is shown that the focused electron beam of

  9. Small round structured viruses (SRSVs) and transmission electron ...

    African Journals Online (AJOL)

    Administrator

    immune-electron microscopy (IEM) from patients' feces. They reported this virus particle as the causative agent of winter vomiting outbreaks in Norwalk (Kapikian et al.,. 1972). This is the remarkable landmark study of non- bacterial gastroenteritis viruses, especially for small round structured viruses (SRSVs). After that, many.

  10. Free electron lasers for transmission of energy in space

    Science.gov (United States)

    Segall, S. B.; Hiddleston, H. R.; Catella, G. C.

    1981-01-01

    A one-dimensional resonant-particle model of a free electron laser (FEL) is used to calculate laser gain and conversion efficiency of electron energy to photon energy. The optical beam profile for a resonant optical cavity is included in the model as an axial variation of laser intensity. The electron beam profile is matched to the optical beam profile and modeled as an axial variation of current density. Effective energy spread due to beam emittance is included. Accelerators appropriate for a space-based FEL oscillator are reviewed. Constraints on the concentric optical resonator and on systems required for space operation are described. An example is given of a space-based FEL that would produce 1.7 MW of average output power at 0.5 micrometer wavelength with over 50% conversion efficiency of electrical energy to laser energy. It would utilize a 10 m-long amplifier centered in a 200 m-long optical cavity. A 3-amp, 65 meV electrostatic accelerator would provide the electron beam and recover the beam after it passes through the amplifier. Three to five shuttle flights would be needed to place the laser in orbit.

  11. Removal of vesicle structures from transmission electron microscope images

    DEFF Research Database (Denmark)

    Jensen, Katrine Hommelhoff; Sigworth, Fred J.; Brandt, Sami Sebastian

    2016-01-01

    In this paper, we address the problem of imaging membrane proteins for single-particle cryo-electron microscopy reconstruction of the isolated protein structure. More precisely, we propose a method for learning and removing the interfering vesicle signals from the micrograph, prior to reconstruct...

  12. Electro-optic techniques in electron beam diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    van Tilborg, Jeroen; Toth, Csaba; Matlis, Nicholas; Plateau, Guillaume; Leemans, Wim

    2011-06-17

    Electron accelerators such as laser wakefield accelerators, linear accelerators driving free electron lasers, or femto-sliced synchrotrons, are capable of producing femtosecond-long electron bunches. Single-shot characterization of the temporal charge profile is crucial for operation, optimization, and application of such accelerators. A variety of electro-optic sampling (EOS) techniques exists for the temporal analysis. In EOS, the field profile from the electron bunch (or the field profile from its coherent radiation) will be transferred onto a laser pulse co-propagating through an electro-optic crystal. This paper will address the most common EOS schemes and will list their advantages and limitations. Strong points that all techniques share are the ultra-short time resolution (tens of femtoseconds) and the single-shot capabilities. Besides introducing the theory behind EOS, data from various research groups is presented for each technique.

  13. Mapping of valence energy losses via energy-filtered annular dark-field scanning transmission electron microscopy.

    Science.gov (United States)

    Gu, Lin; Sigle, Wilfried; Koch, Christoph T; Nelayah, Jaysen; Srot, Vesna; van Aken, Peter A

    2009-08-01

    The advent of electron monochromators has opened new perspectives on electron energy-loss spectroscopy at low energy losses, including phenomena such as surface plasmon resonances or electron transitions from the valence to the conduction band. In this paper, we report first results making use of the combination of an energy filter and a post-filter annular dark-field detector. This instrumental design allows us to obtain energy-filtered (i.e. inelastic) annular dark-field images in scanning transmission electron microscopy of the 2-dimensional semiconductor band-gap distribution of a GaN/Al(45)Ga(55)N structure and of surface plasmon resonances of silver nanoprisms. In comparison to other approaches, the technique is less prone to inelastic delocalization and relativistic artefacts. The mixed contribution of elastic and inelastic contrast is discussed.

  14. Solar Flare Track Exposure Ages in Regolith Particles: A Calibration for Transmission Electron Microscope Measurements

    Science.gov (United States)

    Berger, Eve L.; Keller, Lindsay P.

    2015-01-01

    Mineral grains in lunar and asteroidal regolith samples provide a unique record of their interaction with the space environment. Space weathering effects result from multiple processes including: exposure to the solar wind, which results in ion damage and implantation effects that are preserved in the rims of grains (typically the outermost 100 nm); cosmic ray and solar flare activity, which result in track formation; and impact processes that result in the accumulation of vapor-deposited elements, impact melts and adhering grains on particle surfaces. Determining the rate at which these effects accumulate in the grains during their space exposure is critical to studies of the surface evolution of airless bodies. Solar flare energetic particles (mainly Fe-group nuclei) have a penetration depth of a few millimeters and leave a trail of ionization damage in insulating materials that is readily observable by transmission electron microscope (TEM) imaging. The density of solar flare particle tracks is used to infer the length of time an object was at or near the regolith surface (i.e., its exposure age). Track measurements by TEM methods are routine, yet track production rate calibrations have only been determined using chemical etching techniques [e.g., 1, and references therein]. We used focused ion beam-scanning electron microscope (FIB-SEM) sample preparation techniques combined with TEM imaging to determine the track density/exposure age relations for lunar rock 64455. The 64455 sample was used earlier by [2] to determine a track production rate by chemical etching of tracks in anorthite. Here, we show that combined FIB/TEM techniques provide a more accurate determination of a track production rate and also allow us to extend the calibration to solar flare tracks in olivine.

  15. An Interference-Aware Distributed Transmission Technique for Dense Small Cell Networks

    DEFF Research Database (Denmark)

    Mahmood, Nurul Huda; Berardinelli, Gilberto; Pedersen, Klaus I.

    2015-01-01

    transmission technique that can efficiently manage the interference in an uncoordinated dense small cell network is investigated in this work. The proposed interference aware scheme only requires instantaneous channel state information at the transmitter end towards the desired receiver. Motivated by penalty...... methods in optimization studies, an interference dependent weighting factor is introduced to control the number of parallel transmission streams. The proposed scheme can outperform a more complex benchmark transmission scheme in terms of the sum network throughput in certain scenarios and with realistic...

  16. Incident energy and charge deposition dependences of electron transmission through a microsized tapered glass capillary

    Energy Technology Data Exchange (ETDEWEB)

    Wickramarachchi, S.J. [Department of Physics, Western Michigan University, Kalamazoo, MI 49008 (United States); Ikeda, T. [RIKEN Nishina Center for Accelerator Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Dassanayake, B.S. [Department of Physics, Faculty of Science, University of Peradeniya (Sri Lanka); Keerthisinghe, D.; Tanis, J.A. [Department of Physics, Western Michigan University, Kalamazoo, MI 49008 (United States)

    2016-09-01

    An experimental study of electron transmission and guiding through a tapered glass capillary has been performed. Electrons were transmitted for tilt angles up to ∼6.5° and ∼9.5° (laboratory angles) for incident energies of 500 and 1000 eV, respectively. It is found that elastic and inelastic contributions give rise to distinguishable peaks in the transmitted profile. For 500 eV elastic transmission dominates the profile, while for 1000 eV both elastic and inelastic contributions are present. The transmission for both energies was studied as a function of the charge (time) deposition and found to be strongly dependent. Results suggest fundamental differences between 500 and 1000 eV incident electrons. For 500 eV the transmission slowly increases suggesting charge up of the capillary wall, reaching relative stability with infrequent breakdowns for all angles investigated. For 1000 eV for tilt angles near zero degrees the time dependent profile shows oscillations in the transmission, which never reached a stable condition, while for the larger angle investigated the transmission reached near equilibrium. Inelastic processes dominated the transmission for 1000 eV even at very small tilt angles, but was generally elastic (due to Coulomb deflection) for 500 eV even for the largest tilt angle measured.

  17. Physical methods for studying minerals and solid materials: X-ray, electron and neutron diffraction; scanning and transmission electron microscopy; X-ray, electron and ion spectrometry

    International Nuclear Information System (INIS)

    Eberhart, J.-P.

    1976-01-01

    The following topics are discussed: theoretical aspects of radiation-matter interactions; production and measurement of radiations (X rays, electrons, neutrons); applications of radiation interactions to the study of crystalline materials. The following techniques are presented: X-ray and neutron diffraction, electron microscopy, electron diffraction, X-ray fluorescence analysis, electron probe microanalysis, surface analysis by electron emission spectrometry (ESCA and Auger electrons), scanning electron microscopy, secondary ion emission analysis [fr

  18. Implementation of a virtual correlative light and transmission electron microscope.

    Science.gov (United States)

    Voigt, Tilman; Zuber, Benoît; Gawatz, Gerlinde; Herrmann, Gudrun

    2013-07-01

    In the long run, the widespread use of slide scanners by pathologists requires an adaptation of teaching methods in histology and cytology in order to target these new possibilities of image processing and presentation via the internet. Accordingly, we were looking for a tool with the possibility to teach microscopic anatomy, histology, and cytology of tissue samples which would be able to combine image data from light and electron microscopes independently of microscope suppliers. With the example of a section through the villus of jejunum, we describe here how to process image data from light and electron microscopes in order to get one image-stack which allows a correlation of structures from the microscopic anatomic to the cytological level. With commercially available image-presentation software that we adapted to our needs, we present here a platform which allows for the presentation of this new but also of older material independently of microscope suppliers. Copyright © 2013 Wiley Periodicals, Inc.

  19. First transmission of electrons and ions through the KATRIN beamline

    Czech Academy of Sciences Publication Activity Database

    Arenz, M.; Dragoun, Otokar; Kovalík, Alojz; Lebeda, Ondřej; Ryšavý, Miloš; Sentkerestiová, Jana; Suchopár, Martin; Vénos, Drahoslav

    2018-01-01

    Roč. 13, č. 4 (2018), č. článku P04020. ISSN 1748-0221 R&D Projects: GA MŠk LM2015056; GA MŠk LTT18021 Institutional support: RVO:61389005 Keywords : ion sources * electron beam * detector control systems * beam-line instrumentation * spectrometers Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders OBOR OECD: Nuclear physics Impact factor: 1.220, year: 2016

  20. Robotized semiautomatic motorcycle transmission development. Electronic and software design

    OpenAIRE

    Neghină Mihai; Petruse Radu Emanuil; Olteanu Sebastian; Bondrea Ioan; Lobonț Lucian; Stanciu Gabriel

    2017-01-01

    In this paper, we propose an electrical design (implemented on a PCB board) and an accompanying software design for controlling the automatic gear change. The designs complement the mechanical solutions developed in Part 1. The paper also analyses the issues encountered during the intermediate steps of the development of the electronic module, which is expected to be small and adaptable enough to be installed on a motorcycle without changing its ergonomics. The control software runs on the Ar...

  1. Robust image alignment for cryogenic transmission electron microscopy.

    Science.gov (United States)

    McLeod, Robert A; Kowal, Julia; Ringler, Philippe; Stahlberg, Henning

    2017-03-01

    Cryo-electron microscopy recently experienced great improvements in structure resolution due to direct electron detectors with improved contrast and fast read-out leading to single electron counting. High frames rates enabled dose fractionation, where a long exposure is broken into a movie, permitting specimen drift to be registered and corrected. The typical approach for image registration, with high shot noise and low contrast, is multi-reference (MR) cross-correlation. Here we present the software package Zorro, which provides robust drift correction for dose fractionation by use of an intensity-normalized cross-correlation and logistic noise model to weight each cross-correlation in the MR model and filter each cross-correlation optimally. Frames are reliably registered by Zorro with low dose and defocus. Methods to evaluate performance are presented, by use of independently-evaluated even- and odd-frame stacks by trajectory comparison and Fourier ring correlation. Alignment of tiled sub-frames is also introduced, and demonstrated on an example dataset. Zorro source code is available at github.com/CINA/zorro. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Fine structure of the endolymphatic duct in the rat. A scanning and transmission electron microscopy study

    DEFF Research Database (Denmark)

    Qvortrup, K; Rostgaard, Jørgen; Bretlau, P

    1995-01-01

    and thiocarbohydrazide followed by a continuous dehydration procedure. Three types of cells were identified with the scanning electron microscope: A polygonal and oblong epithelial cell was observed in the largest number throughout the duct, whereas in the juxta-saccular half of the duct two additional types...... of epithelial cells were observed. The scanning electron microscopical observations are compared and discussed with reference to transmission electron microscopical observations of the endolymphatic duct....

  3. Transmission electron microscope studies of crystalline LiNbO3

    International Nuclear Information System (INIS)

    Pareja, R.; Gonzalez, R.; Chen, Y.

    1984-01-01

    Transmission electron microscope investigations in both as-grown and hydrogen-reduced LiNbO 3 reveal that niobium oxide precipitates can be produced by in situ irradiations in the electron microscope. The precipitation process is produced by a combined effect of ionizing electrons and the thermal heating of the specimens during irradiation. It is proposed that the composition of the precipitates is primarily Nb 2 O 5

  4. In Situ Transmission Electron Microscopy Characterization and Manipulation of Two-Dimensional Layered Materials beyond Graphene.

    Science.gov (United States)

    Luo, Chen; Wang, Chaolun; Wu, Xing; Zhang, Jian; Chu, Junhao

    2017-09-01

    Two-dimensional (2D) ultra-thin materials beyond graphene with rich physical properties and unique layered structures are promising for applications in electronics, chemistry, energy, and bioscience, etc. The interaction mechanisms among the structures, chemical compositions and physical properties of 2D layered materials are critical for fundamental nanosciences and the practical fabrication of next-generation nanodevices. Transmission electron microscopy (TEM), with its high spatial resolution and versatile external fields, is undoubtedly a powerful tool for the static characterization and dynamic manipulation of nanomaterials and nanodevices at the atomic scale. The rapid development of thin-film and precision microelectromechanical systems (MEMS) techniques allows 2D layered materials and nanodevices to be probed and engineered inside TEM under external stimuli such as thermal, electrical, mechanical, liquid/gas environmental, optical, and magnetic fields at the nanoscale. Such advanced technologies leverage the traditional static TEM characterization into an in situ and interactive manipulation of 2D layered materials without sacrificing the resolution or the high vacuum chamber environment, facilitating exploration of the intrinsic structure-property relationship of 2D layered materials. In this Review, the dynamic properties tailored and observed by the most advanced and unprecedented in situ TEM technology are introduced. The challenges in spatial, time and energy resolution are discussed also. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Joint denoising and distortion correction of atomic scale scanning transmission electron microscopy images

    Science.gov (United States)

    Berkels, Benjamin; Wirth, Benedikt

    2017-09-01

    Nowadays, modern electron microscopes deliver images at atomic scale. The precise atomic structure encodes information about material properties. Thus, an important ingredient in the image analysis is to locate the centers of the atoms shown in micrographs as precisely as possible. Here, we consider scanning transmission electron microscopy (STEM), which acquires data in a rastering pattern, pixel by pixel. Due to this rastering combined with the magnification to atomic scale, movements of the specimen even at the nanometer scale lead to random image distortions that make precise atom localization difficult. Given a series of STEM images, we derive a Bayesian method that jointly estimates the distortion in each image and reconstructs the underlying atomic grid of the material by fitting the atom bumps with suitable bump functions. The resulting highly non-convex minimization problems are solved numerically with a trust region approach. Existence of minimizers and the model behavior for faster and faster rastering are investigated using variational techniques. The performance of the method is finally evaluated on both synthetic and real experimental data.

  6. Self-assembly of silicon nanowires studied by advanced transmission electron microscopy

    Directory of Open Access Journals (Sweden)

    Marta Agati

    2017-02-01

    Full Text Available Scanning transmission electron microscopy (STEM was successfully applied to the analysis of silicon nanowires (SiNWs that were self-assembled during an inductively coupled plasma (ICP process. The ICP-synthesized SiNWs were found to present a Si–SiO2 core–shell structure and length varying from ≈100 nm to 2–3 μm. The shorter SiNWs (maximum length ≈300 nm were generally found to possess a nanoparticle at their tip. STEM energy dispersive X-ray (EDX spectroscopy combined with electron tomography performed on these nanostructures revealed that they contain iron, clearly demonstrating that the short ICP-synthesized SiNWs grew via an iron-catalyzed vapor–liquid–solid (VLS mechanism within the plasma reactor. Both the STEM tomography and STEM-EDX analysis contributed to gain further insight into the self-assembly process. In the long-term, this approach might be used to optimize the synthesis of VLS-grown SiNWs via ICP as a competitive technique to the well-established bottom-up approaches used for the production of thin SiNWs.

  7. Electron scattering based on a novel internal target technique: SCRIT

    Energy Technology Data Exchange (ETDEWEB)

    Wakasugi, M.; Emoto, T.; Ito, S.; Wang, S.; Suda, T.; Yano, Y. [RIKEN Nishina Center, Saitama (Japan); Kurita, K.; Ishii, K. [Rikkyo University, Rikkyo (Japan); Tamae, T.; Kuwajima, A. [Tohoku University, Tohoku (Japan); Noda, A.; Shiari, T.; Tongu, H. [Kyoto University, Kyoto (Japan)

    2009-12-15

    A novel technique for forming internal targets, named SCRIT (Self-Confining RI Ion Target), has been developed, which can make electron scattering off short-lived radioactive nuclei possible in an electron storage ring. SCRIT confines the ions of interest by utilizing the ''ion trapping'' phenomenon in the electron storage ring. Approximately 10{sup 7} stable {sup 133}Cs ions were trapped in a three-dimensional configuration along the electron beam axis at an electron beam current of 75 mA. The angular distribution of the electrons scattered from the trapped {sup 133}Cs ions was successfully measured, and a collision luminosity of 10{sup 26}/(cm{sup 2} s) was achieved. (orig.)

  8. Electronic control of a 4-speed automatic transmission with lock-up clutch

    Energy Technology Data Exchange (ETDEWEB)

    Schwab, M.

    1984-01-01

    The paper describes the electronic control of an automatic 4-speed transmission with lock-up clutch. As compared to purely hydraulically controlled transmissions, this control offers a clearly improved quality of shifting and the possibility of achieving improvements in fuel consumption thanks to a special economy program. The electronic control unit is a Bosch MOTRONIC which has been expanded to include the functions of transmission control. A special feature is the engine torque control which is implemented by way of retarding the ignition when shifting. This opens up an additional degree of freedom for optimizing a transmission in terms of shift comfort, life of the friction elements and the power which can be transmitted.

  9. Electronic transport on the nanoscale: ballistic transmission and Ohm's law.

    Science.gov (United States)

    Homoth, J; Wenderoth, M; Druga, T; Winking, L; Ulbrich, R G; Bobisch, C A; Weyers, B; Bannani, A; Zubkov, E; Bernhart, A M; Kaspers, M R; Möller, R

    2009-04-01

    If a current of electrons flows through a normal conductor (in contrast to a superconductor), it is impeded by local scattering at defects as well as phonon scattering. Both effects contribute to the voltage drop observed for a macroscopic complex system as described by Ohm's law. Although this concept is well established, it has not yet been measured around individual defects on the atomic scale. We have measured the voltage drop at a monatomic step in real space by restricting the current to a surface layer. For the Si(111)-( [see text]3 x [see text]3)-Ag surface a monotonous transition with a width below 1 nm was found. A numerical analysis of the data maps the current flow through the complex network and the interplay between defect-free terraces and monatomic steps.

  10. Robotized semiautomatic motorcycle transmission development. Electronic and software design

    Directory of Open Access Journals (Sweden)

    Neghină Mihai

    2017-01-01

    Full Text Available In this paper, we propose an electrical design (implemented on a PCB board and an accompanying software design for controlling the automatic gear change. The designs complement the mechanical solutions developed in Part 1. The paper also analyses the issues encountered during the intermediate steps of the development of the electronic module, which is expected to be small and adaptable enough to be installed on a motorcycle without changing its ergonomics. The control software runs on the Arduino Nano board and is built as a state machine with one idle state, five active states that cover different stages of the gear change and one error state for preventing malfunctions in case of an unexpected event. The sketch uses 5,760 bytes (or 18% of program storage space and 706 bytes (or 34% of the dynamic memory.

  11. Characterization of nanocrystalline zirconia powders by electron optical techniques

    International Nuclear Information System (INIS)

    Bursill, L.A.

    1989-01-01

    Electron optical techniques are described for the characterization of the size distribution of agglomerates, aggregates and primary micro- and nanocrystallites of as-processed zirconia powders. These techniques allow for direct identification of individual crystallites as tetragonal or monoclinic, by optical transform of high-resolution electron micrographs. The latter also permit surface morphology to be examined with atomic resolution. Applications to a range of pure and doped zirconia powders, of recent commercial interest, are presented, which enable the results of concurrent studies by sedimentation, surface specific area measurements, porosity and sinterability to be correctly interpreted. 18 figs

  12. A fast iterative technique for restoring scanning electron microscope images

    Energy Technology Data Exchange (ETDEWEB)

    Nakahira, Kenji, E-mail: kenji.nakahira.kp@hitachi.com; Miyamoto, Atsushi; Honda, Toshifumi

    2014-12-21

    This paper proposes a fast new technique for restoring scanning electron microscope images to improve their sharpness. The images with our approach are sharpened by deconvolution with the point spread function modeled as the intensity distribution of the electron beam at the specimen's surface. We propose an iterative technique that employs a modified cost function based on the Richardson–Lucy method to achieve faster processing. The empirical results indicate significant improvements in image quality. The proposed approach speeds up deconvolution by about 10–50 times faster than that with the conventional Richardson–Lucy method.

  13. 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

  14. Transmission properties of Dirac electrons through Cantor monolayer graphene superlattices

    Directory of Open Access Journals (Sweden)

    R. Rodríguez-González

    2014-01-01

    Full Text Available En este trabajo usamos el método de la matriz de transferencia para estudiar el tunelamiento de los electrones de Dirac a través de superredes aperiodicas en grafeno. Consideramos una hoja de grafeno depositada encima de bloques de sustratos de Óxido de Silicio (SiO2 y Carburo de Silicio (SiC, en los cuales aplicamos la serie de Cantor. Calculamos la transmitancia para diferentes parámetros fundamentales tales como: ancho de partida, energía de incidencia, ángulo de incidencia y número de generación de la serie de Cantor. En este caso, la transmitancia como función de la energía presenta rasgos autosimilares al variar el número de generación. También computamos la distribución angular de la transmitancia para energías fijas econtrando un patrón autosimilar entre generaciones. Por último, calculamos los factores de escala para algunos espectros de la transmitancia, los cuales efectivamente muestran escalabilidad.

  15. Scanning and Transmission Electron Microscopy of High Temperature Materials

    Science.gov (United States)

    1994-01-01

    Software and hardware updates to further extend the capability of the electron microscope were carried out. A range of materials such as intermetallics, metal-matrix composites, ceramic-matrix composites, ceramics and intermetallic compounds, based on refractory elements were examined under this research. Crystal structure, size, shape and volume fraction distribution of various phases which constitute the microstructures were examined. Deformed materials were studied to understand the effect of interfacial microstructure on the deformation and fracture behavior of these materials. Specimens tested for a range of mechanical property requirements, such as stress rupture, creep, low cycle fatigue, high cycle fatigue, thermomechanical fatigue, etc. were examined. Microstructural and microchemical stability of these materials exposed to simulated operating environments were investigated. The EOIM Shuttle post-flight samples were also examined to understand the influence of low gravity processing on microstructure. In addition, fractographic analyses of Nb-Zr-W, titanium aluminide, molybdenum silicide and silicon carbide samples were carried out. Extensive characterization of sapphire fibers in the fiber-reinforced composites made by powder cloth processing was made. Finally, pressure infiltration casting of metal-matrix composites was carried out.

  16. Transmission Electron Microscopy of Bombyx Mori Silk Fibers

    Science.gov (United States)

    Shen, Y.; Martin, D. C.

    1997-03-01

    The microstructure of B. Mori silk fibers before and after degumming was examined by TEM, selected area electron diffraction (SAED), WAXS and low voltage SEM. SEM micrographs of the neat cocoon revealed a network of pairs of twisting filaments. After degumming, there were only individual filaments showing a surface texture consistent with an oriented fibrillar structure in the fiber interior. WAXS patterns confirmed the oriented beta-sheet crystal structure common to silkworm and spider silks. Low dose SAED results were fully consistent with the WAXS data, and revealed that the crystallographic texture did not vary significantly across the fiber diameter. TEM observations of microtomed fiber cross sections indicated a somewhat irregular shape, and also revealed a 0.5-2 micron sericin coating which was removed by the degumming process. TEM observations of the degummed silk fiber showed banded features with a characteristic spacing of nominally 600 nm along the fiber axis. These bands were oriented in a roughly parabolic or V-shape pointing along one axis within a given fiber. We hypothesize that this orientation is induced by the extrusion during the spinning process. Equatorial DF images revealed that axial and lateral sizes of the β-sheet crystallites in silk fibroin ranged from 20 to 170 nm and from 1 to 24 nm, respectively. Crazes developed in the degummed silk fiber parallel to the fiber direction. The formation of these crazes suggests that there are significant lateral interactions between fibrils in silk fibers.

  17. Development of Wireless Techniques in Data and Power Transmission - Application for Particle Physics Detectors

    CERN Document Server

    Locci, E.; Dehos, C.; De Lurgio, P.; Djurcic, Z.; Drake, G.; Gimenez, J. L. Gonzalez; Gustafsson, L.; Kim, D.W.; Roehrich, D.; Schoening, A.; Siligaris, A.; Soltveit, H.K.; Ullaland, K.; Vincent, P.; Wiednert, D.; Yang, S.; Brenner, R.

    2015-01-01

    Wireless techniques have developed extremely fast over the last decade and using them for data and power transmission in particle physics detectors is not science- fiction any more. During the last years several research groups have independently thought of making it a reality. Wireless techniques became a mature field for research and new developments might have impact on future particle physics experiments. The Instrumentation Frontier was set up as a part of the SnowMass 2013 Community Summer Study [1] to examine the instrumentation R&D for the particle physics research over the coming decades: {\\guillemotleft} To succeed we need to make technical and scientific innovation a priority in the field {\\guillemotright}. Wireless data transmission was identified as one of the innovations that could revolutionize the transmission of data out of the detector. Power delivery was another challenge mentioned in the same report. We propose a collaboration to identify the specific needs of different projects that m...

  18. Turbo Equalization Techniques Toward Robust PDM 16-QAM Optical Fiber Transmission

    DEFF Research Database (Denmark)

    Arlunno, Valeria; Caballero Jambrina, Antonio; Borkowski, Robert

    2014-01-01

    In this paper, we show numerically and experimentally that turbo equalization (TE) is an efficient technique to mitigate performance degradations stemming from optical fiber propagation effects in both optical fiber dispersion managed and unmanaged coherent detection links. The effectiveness....... As TE can be included in the current coherent detection transceiver technologies and complement other equalization techniques, it has prospects for application in next-generation high-capacity and long-reach optical transmission links....

  19. Enhanced thermal stability of a polymer solar cell blend induced by electron beam irradiation in the transmission electron microscope.

    Science.gov (United States)

    Bäcke, Olof; Lindqvist, Camilla; de Zerio Mendaza, Amaia Diaz; Gustafsson, Stefan; Wang, Ergang; Andersson, Mats R; Müller, Christian; Kristiansen, Per Magnus; Olsson, Eva

    2017-05-01

    We show by in situ microscopy that the effects of electron beam irradiation during transmission electron microscopy can be used to lock microstructural features and enhance the structural thermal stability of a nanostructured polymer:fullerene blend. Polymer:fullerene bulk-heterojunction thin films show great promise for use as active layers in organic solar cells but their low thermal stability is a hindrance. Lack of thermal stability complicates manufacturing and influences the lifetime of devices. To investigate how electron irradiation affects the thermal stability of polymer:fullerene films, a model bulk-heterojunction film based on a thiophene-quinoxaline copolymer and a fullerene derivative was heat-treated in-situ in a transmission electron microscope. In areas of the film that exposed to the electron beam the nanostructure of the film remained stable, while the nanostructure in areas not exposed to the electron beam underwent large phase separation and nucleation of fullerene crystals. UV-vis spectroscopy shows that the polymer:fullerene films are stable for electron doses up to 2000kGy. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Transmission electron microscopy investigation of the microstructure and chemistry of Si/Cu/In/Cu/Si interconnections

    International Nuclear Information System (INIS)

    Sommadossi, S.; Litynska, L.; Zieba, P.; Gust, W.; Mittemeijer, E.J.

    2003-01-01

    Si/Si interconnections, obtained using a Cu metallization and an In interlayer and joined by diffusion soldering are presented. The Si/Cu/In/Cu/Si bonds were accomplished due to isothermal solidification and subsequent interdiffusion of In and Cu in the samples held at 180 deg. C. Application of a transmission electron microscope (TEM) with an attachment for high-resolution chemical analysis allowed characterizing the microstructural and microchemical feature of the intermetallics formed in the joint. Appearance of two phases, namely η(Cu 2 In) and δ(Cu 7 In 3 ), was confirmed by electron diffraction patterns and energy-dispersive X-ray (EDX) analysis. The bond quality and the high melting point of the phases (∼630 deg. C) indicate a great potential of this technique for joining of integrated circuits in electronics

  1. The behavior of moisture content in Durian after harvesting by neutron reflection and transmission techniques

    International Nuclear Information System (INIS)

    Chimoye, T.; Fuangfoong, M.

    1998-01-01

    The study aimed at development of a neutron reflection and transmission technique to determine moisture content in Durian fruit as a function of time after harvesting. A system of a 3 mCi Am-Be neutron source with a BF 3 detector as a neutron probe was developed. The results obtained were validated using weighting method

  2. Oral leukoplakia: Transmission electron microscopic correlation with clinical types and light microscopy

    Science.gov (United States)

    Tamgadge, Sandhya Avinash; Ganvir, Sindhu Milind; Hazarey, Vinay Krishnarao; Tamgadge, Avinash

    2012-01-01

    Background: Leukoplakia, is a precancerous lesion that is most commonly encountered in the oral cavity. The grade of dysplasia is presumed to be the most important indicator of malignant potential. There are many promising aspects in advanced methods for the evaluation of oral precancer and cancer. Among these methods, electron microscopic examination predicts the true biologic potential more accurately than conventional histology and has some success in the early detection of potentially malignant lesions. It has been reported in the literature that there is some correlation between clinical, histopathological, and transmission electron microscopic features. Materials and Methods: In this cohort study (prospective research), from the total of 9 subjects, 3 had homogenous leukoplakia, 3 had ulcerative type of oral leukoplakia, and 3 had nodular type of oral leukoplakia. Two patients were selected as control patients. Transmission electron microscopic examination was carried for all the cases and controls. All the findings were correlated with clinical features and light microscopy. Results: Clinically and histologically, mild leukoplakia showed break in basement membrane, which can only be observed under transmission electron microscope (TEM). Additional dysplastic features were observed under transmission electron microscope, which are indicative of neoplastic process. Conclusions: Thus, it is finally concluded that nodular leukoplakia seems to be the most severe clinical type of leukoplakia showing highest risk of malignant transformation. Homogenous leukoplakia might show break in basement membrane under TEM. PMID:23814570

  3. 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

  4. Assessing and ameliorating the influence of the electron beam on carbon nanotube oxidation in environmental transmission electron microscopy

    International Nuclear Information System (INIS)

    Koh, Ai Leen; Sinclair, Robert

    2017-01-01

    In this work, we examine how the imaging electron beam can induce damage in carbon nanotubes (CNTs) at varying oxygen gas pressures and electron dose rates using environmental transmission electron microscopy (ETEM). Our studies show that there is a threshold cumulative electron dose which brings about damage in CNTs in oxygen – through removal of their graphitic walls – which is dependent on O 2 pressure, with a 4–5 fold decrease in total electron dose per decade increase at a lower pressure range (10 −6 to 10 −5 mbar) and approximately 1.3 –fold decrease per decade increase at a higher pressure range (10 −3 to 10 0 mbar). However, at a given pressure, damage in CNTs was found to occur even at the lowest dose rate utilized, suggesting the absence of a lower limit for the latter parameter. This study provides guidelines on the cumulative dose required to damage nanotubes in the 10 −7 mbar to 10 0 mbar pressure regimes, and discusses the role of electron dose rate and total electron dose on beam-induced CNT degradation experiments. - Highlights: • The electron beam ionizes gas molecules in ETEM and affects experimental outcomes. • Beam-induced damage in CNTs occurs at varying O 2 pressures and electron dose rates. • There is a threshold cumulative dose to damage CNTs which depends on O 2 pressure. • At a given pressure, CNT damage occurs even at the electron dose rate utilized.

  5. Solid-state nanopores of controlled geometry fabricated in a transmission electron microscope

    Science.gov (United States)

    Qian, Hui; Egerton, Ray F.

    2017-11-01

    Energy-filtered transmission electron microscopy and electron tomography were applied to in situ studies of the formation, shape, and diameter of nanopores formed in a silicon nitride membrane in a transmission electron microscope. The nanopore geometry was observed in three dimensions by electron tomography. Drilling conditions, such as probe current, beam convergence angle, and probe position, affect the formation rate and the geometry of the pores. With a beam convergence semi-angle of α = 22 mrad, a conical shaped nanopore is formed but at α = 45 mrad, double-cone (hourglass-shaped) nanopores were produced. Nanopores with an effective diameter between 10 nm and 1.8 nm were fabricated by controlling the drilling time.

  6. The Development of a Hibachi Window for Electron Beam Transmission in a KrF Laser

    International Nuclear Information System (INIS)

    Gentile, C.A.; Parsells, R.; Butler, J.E.; Sethian, J.D.; Ciebiera, L.; Hegeler, F.; Jun, C.; Langish, S.; Myers, M.

    2003-01-01

    In support of Inertial Fusion Energy (IFE), a 150 (micro)m thick silicon (Si) wafer coated on one side with a 1.2 (micro)m nanocrystalline diamond foil is being fabricated as an electron beam transmission (hibachi) window for use in KrF lasers. The hibachi window separates the lasing medium from the electron beam source while allowing the electron beam to pass through. The hibachi window must be capable of withstanding the challenging environment presented in the lasing chamber, which include: fluorine gas, delta pressure >2 atm at 5 Hz, and a high heat flux due to the transmission of electrons passing through the foil. Tests at NRL/Electra and at PPPL have shown that a device employing these novel components in the stated configuration provide for a robust hibachi window with structural integrity

  7. Convergent beam electron diffraction – A novel technique for ...

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    This, together with the use of cooled CCD cameras, online work stations and figures, brings us to applying this technique to a wide range of problems in materials science, solid state chemistry, mineralogy and condensed matter physics. 3. Basic principles. Conventionally, until the discovery of CBED, electron diffraction from ...

  8. Electronics system design techniques for safety critical applications

    CERN Document Server

    Sterpone, Luca

    2008-01-01

    Addresses the development of techniques for the evaluation and the hardening of designs implemented on SRAM-based Field Programmable Gate Arrays. This title presents a design methodology solving industrial designer''s needs for implementing electronic systems using SRAM-based FPGAs in critical environments, like the space or avionic ones.

  9. Transmission electron microscope interfaced with ion accelerators and its application to materials science

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Hiroaki; Naramoto, Hiroshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Hojou, Kiichi; Furuno, Shigemi; Tsukamoto, Tetsuo

    1997-03-01

    We have developed the transmission/analytical electron microscope interfaced with two sets of ion accelerators (TEM-Accelerators Facility) at JAERI-Takasaki. The facility is expected to provide quantitative insights into radiation effects, such as damage evolution, irradiation-induced phase transformation and their stability, through in-situ observation and analysis under ion and/or electron irradiation. The TEM-Accelerators Facility and its application to materials research are reviewed. (author)

  10. Facilities for in situ ion beam studies in transmission electron microscopes

    International Nuclear Information System (INIS)

    Allen, C.W.; Ohnuki, S.; Takahashi, H.

    1993-08-01

    Interfacing an ion accelerator to a transmission electron microscope (TEM) allows the analytical functions of TEM imaging and electron diffraction from very small regions to be employed during ion-irradiation effects studies. At present there are ten such installations in Japan, one in France and one in the USA. General specifications of facilities which are operational in 1993 are summarized, and additional facilities which are planned or being proposed are briefly described

  11. 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.

  12. Anatomy-based transmission factors for technique optimization in portable chest x-ray

    Science.gov (United States)

    Liptak, Christopher L.; Tovey, Deborah; Segars, William P.; Dong, Frank D.; Li, Xiang

    2015-03-01

    Portable x-ray examinations often account for a large percentage of all radiographic examinations. Currently, portable examinations do not employ automatic exposure control (AEC). To aid in the design of a size-specific technique chart, acrylic slabs of various thicknesses are often used to estimate x-ray transmission for patients of various body thicknesses. This approach, while simple, does not account for patient anatomy, tissue heterogeneity, and the attenuation properties of the human body. To better account for these factors, in this work, we determined x-ray transmission factors using computational patient models that are anatomically realistic. A Monte Carlo program was developed to model a portable x-ray system. Detailed modeling was done of the x-ray spectrum, detector positioning, collimation, and source-to-detector distance. Simulations were performed using 18 computational patient models from the extended cardiac-torso (XCAT) family (9 males, 9 females; age range: 2-58 years; weight range: 12-117 kg). The ratio of air kerma at the detector with and without a patient model was calculated as the transmission factor. Our study showed that the transmission factor decreased exponentially with increasing patient thickness. For the range of patient thicknesses examined (12-28 cm), the transmission factor ranged from approximately 21% to 1.9% when the air kerma used in the calculation represented an average over the entire imaging field of view. The transmission factor ranged from approximately 21% to 3.6% when the air kerma used in the calculation represented the average signals from two discrete AEC cells behind the lung fields. These exponential relationships may be used to optimize imaging techniques for patients of various body thicknesses to aid in the design of clinical technique charts.

  13. Simulations of the electron cloud buildup and its influence on the microwave transmission measurement

    Energy Technology Data Exchange (ETDEWEB)

    Haas, Oliver Sebastian, E-mail: o.haas@gsi.de [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt (Germany); Boine-Frankenheim, Oliver [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt (Germany); Technische Universität Darmstadt, Institut für Theorie Elektromagnetischer Felder, Schlossgartenstraße 8, 64289 Darmstadt (Germany); Petrov, Fedor [Technische Universität Darmstadt, Institut für Theorie Elektromagnetischer Felder, Schlossgartenstraße 8, 64289 Darmstadt (Germany)

    2013-11-21

    An electron cloud density in an accelerator can be measured using the Microwave Transmission (MWT) method. The aim of our study is to evaluate the influence of a realistic, nonuniform electron cloud on the MWT. We conduct electron cloud buildup simulations for beam pipe geometries and bunch parameters resembling roughly the conditions in the CERN SPS. For different microwave waveguide modes the phase shift induced by a known electron cloud density is obtained from three different approaches: 3D Particle-In-Cell (PIC) simulation of the electron response, a 2D eigenvalue solver for waveguide modes assuming a dielectric response function for cold electrons, a perturbative method assuming a sufficiently smooth density profile. While several electron cloud parameters, such as temperature, result in minor errors in the determined density, the transversely inhomogeneous density can introduce a large error in the measured electron density. We show that the perturbative approach is sufficient to describe the phase shift under realistic electron cloud conditions. Depending on the geometry of the beam pipe, the external magnetic field configuration and the used waveguide mode, the electron cloud density can be concentrated at the beam pipe or near the beam pipe center, leading to a severe over- or underestimation of the electron density. -- Author-Highlights: •Electron cloud distributions are very inhomogeneous, especially in dipoles. •These inhomogeneities affect the microwave transmission measurement results. •Electron density might be over- or underestimated, depending on setup. •This can be quantified with several models, e.g. a perturbative approach.

  14. In-situ transmission electron microscopy observation of electromigration in Au thin wires.

    Science.gov (United States)

    Murakami, Yosuke; Arita, Masashi; Hamada, Kouichi; Takahashi, Yasuo

    2012-11-01

    Electromigration of thin Au wire is studied by the use of in-situ transmission electron microscopy (TEM) techniques from the viewpoint of nanogap formation. We use a relatively wide Au wire as a starting material because the position-dependent structure change in the wire provides information of the thermal effect caused by the current flow. In-situ TEM observation, in which current measurements of the Au wire are simultaneously performed, reveals the process of the growth of voids and grains. Finally the formation of a nanogap by electromigration is observed doing with current measurements. All the results observed by in-situ TEM indicate the fact that the thermal effects or temperature increase in the wire region take an important role for the structure change caused by electromigration of Au in the wire. It is suggested that the position of the nanogap can roughly be arranged by setting the wire structure and current direction even though a relatively wide wire was used. The detailed observation by in-situ TEM also suggests that the control of heat generation in the wire makes the nanogap sharp because of the well-controlled recrystallization of Au nanowires.

  15. In situ oxidation and reduction of triangular nickel nanoplates via environmental transmission electron microscopy

    KAUST Repository

    LAGROW, A.P.

    2017-08-29

    Understanding the oxidation and reduction mechanisms of transition metals, such as nickel (Ni), is important for their use in industrial applications of catalysis. A powerful technique for investigating the redox reactive species is in situ environmental transmission electron microscopy (ETEM), where oxidation and reduction can be tracked in real time. One particular difficulty in understanding the underlying reactions is understanding the underlying morphology of the starting structure in a reaction, in particular the defects contained in the material, and the exposed surface facets. Here-in, we use a colloidal nanoparticle synthesis in a continuous flow reactor to form nanoplates of nickel coated with oleylamine as a capping agent. We utilise an in situ heating procedure at 300 °C in vacuum to remove the oleylamine ligands, and then oxidise the Ni nanoparticles at 25 °C with 2 Pa oxygen, and follow the nanoparticles initial oxidation. After that, the nanoparticles are oxidised at 200 and 300 °C, making the size of the oxide shell increase to ∼4 nm. The oxide shell could be reduced under 2 Pa hydrogen at 500 °C to its initial size of ∼1 nm. High temperature oxidation encouraged the nanoparticles to form pure NiO nanoparticles, which occurred via the Kirkendall effect leading to hollowing and void formation.

  16. Evaluating transmission electron microscopy as a method for assessing the condition of archaeological wool

    DEFF Research Database (Denmark)

    Scharff, Annemette Bruselius; Jørgensen, Lise Bolt

    2017-01-01

    Transmission electron microscopy (TEM) was investigated to clarify the applicability of the method for assessing the condition of archaeological textiles from waterlogged environments. A description and evaluation of the TEM protocol is presented and the method was tested on new and artificially...

  17. Ultrathin sectioning of polymeric materials for low-voltage transmission electron microscopy. Relief on ultrathin sections

    Czech Academy of Sciences Publication Activity Database

    Lednický, František; Pientka, Zbyněk; Hromádková, Jiřina

    2003-01-01

    Roč. 42, č. 5 (2003), s. 1039-1047 ISSN 0022-2348 R&D Projects: GA AV ČR IBS4050008 Institutional research plan: CEZ:AV0Z4050913 Keywords : cutting ultrathin sections * low-voltage scanning transmission electron microscopy * polymer blend s Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.679, year: 2003

  18. Thermal stability of catalytically grown multi-walled carbon nanotubes observed in transmission electron microscopy

    DEFF Research Database (Denmark)

    Wang, Cheng-Yu; Liu, Chuan-Pu; Boothroyd, Chris

    2009-01-01

    The thermal stability of multi-walled carbon nanotubes (MWCNTs) was assessed in situ by transmission electron microscopy. Upon heating, Ni catalysts in MWC-NTs containing bamboo structures shrank from the tail due to evaporation, leading to additional bamboo formation and tube elongation at 800...

  19. Accuracy of surface strain measurements from transmission electron microscopy images of nanoparticles

    DEFF Research Database (Denmark)

    Madsen, Jacob; Liu, Pei; Wagner, Jakob Birkedal

    2017-01-01

    Strain analysis from high-resolution transmission electron microscopy (HRTEM) images offers a convenient tool for measuring strain in materials at the atomic scale. In this paper we present a theoretical study of the precision and accuracy of surface strain measurements directly from aberration...

  20. 3D estimation of synaptic vesicle distributions in serial section transmission electron microscopy

    DEFF Research Database (Denmark)

    Khanmohammadi, Mahdieh; Darkner, Sune; Nava, Nicoletta

    directly. It is hypothesized that in a rat model of behavioral stress the vesicles distribution varies. We propose methods for estimating the 3-dimensional distribution of synaptic vesicles from the active zone through serial section transmission electron microscope images (ssTEM) from Sprague-Dawley rat...

  1. Cryo-transmission electron microscopy of a superstructure of fluid dioleoylphosphatidylcholine (DOPC) membranes

    DEFF Research Database (Denmark)

    Klösgen, B; Helfrich, W

    1997-01-01

    Using cryo-transmission electron microscopy, we have obtained abundant and reproducible evidence for a superstructure of dioleoylphosphatidylcholine (DOPC) bilayers. Dispersions of vesicles were prepared by gentle shaking of a 2% suspension of DOPC in water followed in part by extrusion through...

  2. Transmission electron microscopy investigation of colloids and particles from landfill leachates

    Czech Academy of Sciences Publication Activity Database

    Matura, M.; Ettler, V.; Klementová, Mariana

    2012-01-01

    Roč. 30, č. 5 (2012), s. 530-541 ISSN 0734-242X Institutional research plan: CEZ:AV0Z40320502 Keywords : colloids * landfill leachates * transmission electron microscopy * calcite * contaminant mobility Subject RIV: CA - Inorganic Chemistry Impact factor: 1.047, year: 2012

  3. Magnetic imaging with a Zernike-type phase plate in a transmission electron microscope

    DEFF Research Database (Denmark)

    Pollard, Shawn; Malac, Marek; Beleggia, Marco

    2013-01-01

    We demonstrate the use of a hole-free phase plate (HFPP) for magnetic imaging in transmission electron microscopy by mapping the domain structure in PrDyFeB samples. The HFPP, a Zernike-like imaging method, allows for detecting magnetic signals in-focus to correlate the sample crystal structure a...

  4. Three-dimensional visualization and characterization of polymeric self-assemblies by Transmission Electron Microtomography

    NARCIS (Netherlands)

    H. Jinnai (Hiroshi); T. Higuchi (Takeshi); X. Zhuge (Jason); A. Kumamoto (Akihito); K.J. Batenburg (Joost); Y. Ikuhara (Yuichi)

    2017-01-01

    textabstractSelf-assembling structures and their dynamical processes in polymeric systems have been investigated using three-dimensional transmission electron microscopy (3D-TEM). Block copolymers (BCPs) self-assemble into nanoscale periodic structures called microphase-separated structures, a deep

  5. In-situ transmission electron microscopy : on moving dislocations and mobile grain boundaries

    NARCIS (Netherlands)

    De Hosson, J. T. M.; Soer, W.

    This paper delineates the possibilities of utilizing in situ transmission electron microscopy to unravel dislocation-g rain boundary interactions. In situ nanoindentation experiments have been conducted in TEM on ultrafine-grained Al and Al-Mg films with varying Mg contents. The observed propagation

  6. Transmission Electron Microscopy Specimen Preparation Method for Multiphase Porous Functional Ceramics

    DEFF Research Database (Denmark)

    Zhang, Wei; Kuhn, Luise Theil; Jørgensen, Peter Stanley

    2013-01-01

    An optimum method is proposed to prepare thin foil transmission electron microscopy (TEM) lamellae of multiphase porous functional ceramics: prefilling the pore space of these materials with an epoxy resin prior to focused ion beam milling. Several advantages of epoxy impregnation are demonstrate...

  7. In situ transmission electron microscopy studies on structural dynamics of transition metal nanoclusters

    NARCIS (Netherlands)

    Vystavel, T.; Koch, S.A.; Palasantzas, G.; Hosson, J.Th.M. De

    The structural stability of transition metal nanoclusters has been scrutinized with in situ transmission electron microscopy as a function of temperature. In particular iron, cobalt, niobium, and molybdenum clusters with diameters around 5 nm have been investigated. During exposure to air, a thin

  8. Current status and future directions for in situ transmission electron microscopy

    DEFF Research Database (Denmark)

    Taheri, Mitra L.; Stach, Eric A.; Arslan, Ilke

    2016-01-01

    This review article discusses the current and future possibilities for the application of in situ transmission electron microscopy to reveal synthesis pathways and functional mechanisms in complex and nanoscale materials. The findings of a group of scientists, representing academia, government labs...

  9. Quantitative analysis of structural inhomogeneity in nanomaterials using transmission electron microscopy

    Czech Academy of Sciences Publication Activity Database

    Klinger, Miloslav; Polívka, Leoš; Jäger, Aleš; Tyunina, Marina

    2016-01-01

    Roč. 49, Jun (2016), 762-770 ISSN 1600-5767 R&D Projects: GA ČR GBP108/12/G043; GA ČR GA15-15123S Institutional support: RVO:68378271 Keywords : transmission electron microscopy * structural inhomogeneity * lattice parameters * image processing Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.495, year: 2016

  10. Advances in Transmission Electron Microscopy : In Situ Straining and In Situ Compression Experiments on Metallic Glasses

    NARCIS (Netherlands)

    De Hosson, Jeff Th. M.

    In the field of transmission electron microscopy (TEM), fundamental and practical reasons still remain that hamper a straightforward correlation between microscopic structural information and deformation mechanisms in materials. In this article, it is argued that one should focus in particular on in

  11. Transmission Electron Microscopic Study of Antibiotic Action on Klebsiella pneumoniae Biofilm

    OpenAIRE

    Zahller, Jeff; Stewart, Philip S.

    2002-01-01

    The penetration of ampicillin and ciprofloxacin through biofilms formed by Klebsiella pneumoniae was confirmed by transmission electron microscopic observation of antibiotic-affected cells at the distal edge of the biofilm. Because the bacteria nevertheless survived antibiotic treatment, some protective mechanism other than inadequate penetration must have been at work in the biofilm.

  12. Whole-cell imaging of the budding yeast Saccharomyces cerevisiae by high-voltage scanning transmission electron tomography

    Energy Technology Data Exchange (ETDEWEB)

    Murata, Kazuyoshi, E-mail: kazum@nips.ac.jp [National Institute for Physiological Sciences, Okazaki, Aichi 444-8585 (Japan); Esaki, Masatoshi; Ogura, Teru [Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811 (Japan); Arai, Shigeo; Yamamoto, Yuta; Tanaka, Nobuo [Ecotopia Science Institute, Nagoya University, Nagoya, Aichi 464-8603 (Japan)

    2014-11-15

    Electron tomography using a high-voltage electron microscope (HVEM) provides three-dimensional information about cellular components in sections thicker than 1 μm, although in bright-field mode image degradation caused by multiple inelastic scattering of transmitted electrons limit the attainable resolution. Scanning transmission electron microscopy (STEM) is believed to give enhanced contrast and resolution compared to conventional transmission electron microscopy (CTEM). Samples up to 1 μm in thickness have been analyzed with an intermediate-voltage electron microscope because inelastic scattering is not a critical limitation, and probe broadening can be minimized. Here, we employed STEM at 1 MeV high-voltage to extend the useful specimen thickness for electron tomography, which we demonstrate by a seamless tomographic reconstruction of a whole, budding Saccharomyces cerevisiae yeast cell, which is ∼3 μm in thickness. High-voltage STEM tomography, especially in the bright-field mode, demonstrated sufficiently enhanced contrast and intensity, compared to CTEM tomography, to permit segmentation of major organelles in the whole cell. STEM imaging also reduced specimen shrinkage during tilt-series acquisition. The fidelity of structural preservation was limited by cytoplasmic extraction, and the spatial resolution was limited by the relatively large convergence angle of the scanning probe. However, the new technique has potential to solve longstanding problems of image blurring in biological specimens beyond 1 μm in thickness, and may facilitate new research in cellular structural biology. - Highlights: • High voltage TEM and STEM tomography were compared to visualize whole yeast cells. • 1-MeV STEM-BF tomography had significant improvements in image contrast and SNR. • 1-MeV STEM tomography showed less specimen shrinkage than the TEM tomography. • KMnO{sub 4} post-treatment permitted segmenting the major cellular components.

  13. 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.

  14. Mechanical characterization of diesel soot nanoparticles: in situ compression in a transmission electron microscope and simulations

    Science.gov (United States)

    Jenei, Istvan Zoltan; Dassenoy, Fabrice; Epicier, Thierry; Khajeh, Arash; Martini, Ashlie; Uy, Dairene; Ghaednia, Hamed; Gangopadhyay, Arup

    2018-02-01

    Incomplete fuel burning inside an internal combustion engine results in the creation of soot in the form of nanoparticles. Some of these soot nanoparticles (SNP) become adsorbed into the lubricating oil film present on the cylinder walls, which adversely affects the tribological performance of the lubricant. In order to better understand the mechanisms underlying the wear caused by SNPs, it is important to understand the behavior of SNPs and to characterize potential changes in their mechanical properties (e.g. hardness) caused by (or during) mechanical stress. In this study, the behavior of individual SNPs originating from diesel engines was studied under compression. The experiments were performed in a transmission electron microscope using a nanoindentation device. The nanoparticles exhibited elasto-plastic behavior in response to consecutive compression cycles. From the experimental data, the Young’s modulus and hardness of the SNPs were calculated. The Young’s modulus and hardness of the nanoparticles increased with the number of compression cycles. Using an electron energy loss spectroscopy technique, it was shown that the sp2/sp3 ratio within the compressed nanoparticle decreases, which is suggested to be the cause of the increase in elasticity and hardness. In order to corroborate the experimental findings, molecular dynamics simulations of a model SNP were performed. The SNP model was constructed using carbon and hydrogen atoms with morphology and composition comparable to those observed in the experiment. The model SNP was subjected to repeated compressions between two virtual rigid walls. During the simulation, the nanoparticle exhibited elasto-plastic behavior like that in the experiments. The results of the simulations confirm that the increase in the elastic modulus and hardness is associated with a decrease in the sp2/sp3 ratio.

  15. Attosecond electron pulse trains and quantum state reconstruction in ultrafast transmission electron microscopy

    Science.gov (United States)

    Priebe, Katharina E.; Rathje, Christopher; Yalunin, Sergey V.; Hohage, Thorsten; Feist, Armin; Schäfer, Sascha; Ropers, Claus

    2017-12-01

    Ultrafast electron and X-ray imaging and spectroscopy are the basis for an ongoing revolution in the understanding of dynamical atomic-scale processes in matter. The underlying technology relies heavily on laser science for the generation and characterization of ever shorter pulses. Recent findings suggest that ultrafast electron microscopy with attosecond-structured wavefunctions may be feasible. However, such future technologies call for means to both prepare and fully analyse the corresponding free-electron quantum states. Here, we introduce a framework for the preparation, coherent manipulation and characterization of free-electron quantum states, experimentally demonstrating attosecond electron pulse trains. Phase-locked optical fields coherently control the electron wavefunction along the beam direction. We establish a new variant of quantum state tomography—`SQUIRRELS'—for free-electron ensembles. The ability to tailor and quantitatively map electron quantum states will promote the nanoscale study of electron-matter entanglement and new forms of ultrafast electron microscopy down to the attosecond regime.

  16. 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.

  17. Ultrafast transmission electron microscopy using a laser-driven field emitter: Femtosecond resolution with a high coherence electron beam.

    Science.gov (United States)

    Feist, Armin; Bach, Nora; Rubiano da Silva, Nara; Danz, Thomas; Möller, Marcel; Priebe, Katharina E; Domröse, Till; Gatzmann, J Gregor; Rost, Stefan; Schauss, Jakob; Strauch, Stefanie; Bormann, Reiner; Sivis, Murat; Schäfer, Sascha; Ropers, Claus

    2017-05-01

    We present the development of the first ultrafast transmission electron microscope (UTEM) driven by localized photoemission from a field emitter cathode. We describe the implementation of the instrument, the photoemitter concept and the quantitative electron beam parameters achieved. Establishing a new source for ultrafast TEM, the Göttingen UTEM employs nano-localized linear photoemission from a Schottky emitter, which enables operation with freely tunable temporal structure, from continuous wave to femtosecond pulsed mode. Using this emission mechanism, we achieve record pulse properties in ultrafast electron microscopy of 9Å focused beam diameter, 200fs pulse duration and 0.6eV energy width. We illustrate the possibility to conduct ultrafast imaging, diffraction, holography and spectroscopy with this instrument and also discuss opportunities to harness quantum coherent interactions between intense laser fields and free-electron beams. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  18. First combined electron backscatter diffraction and transmission electron microscopy study of grain boundary structure of deformed quartzite.

    Science.gov (United States)

    Shigematsu, N; Prior, D J; Wheeler, J

    2006-12-01

    The structures of boundaries in a deformed and dynamically recovered and recrystallized quartz polycrystal (mylonite) were characterized by transmission electron microscopy, after the misorientation angles across the same grain boundaries had been analysed using electron backscatter diffraction in a scanning electron microscope. In this new approach, a specific sample area is mapped with electron backscatter diffraction, and the mapped area is then attached to a foil, and by the ion beam thinned for transmission electron microscopy analysis. Dislocations in grain boundaries were recognized as periodic and parallel fringes. The fringes associated with dislocations are observed in boundaries with misorientations less than 9 degrees , whereas such fringes cannot be seen in the boundaries with misorientations larger than 17 degrees . Some boundaries with misorientations between 9 degrees and 17 degrees generally have no structures associated with dislocation. One segment of a boundary with a misorientation of 13.5 degrees has structures associated with dislocations. It is likely that the transition from low-angle to high-angle boundaries occurs at misorientations ranging from approximately 9 degrees to 14 degrees . Change in the grain boundary structure presumably influences the mobility of the boundaries. In the studied deformed quartz vein, a relative dearth of boundaries between misorientation angles of theta = 2 degrees and theta = 15 degrees has previously been reported, and high-angle boundaries form cusps where they intersect low-angle boundaries, suggesting substantial mobility of high-angle boundaries.

  19. Numerical study of electron-leakage power loss in a tri-plate transmission line

    International Nuclear Information System (INIS)

    Barker, R.J.; Goldstein, S.A.

    1982-01-01

    Numerical simulations have been conducted using NRL's DIODE2D computer code to model the steady-state behavior of electron flow in a radial diode and in its adjacent tri-plate transmission line (TTL). Particular attention was paid to the magnitude of the electron current flowing from the cathode to the anode surface in the TTL. A quantitative value for this effective power loss is given. The electron current is restricted mainly to the transition region in the TTL into which there is seepage of the B/sub z/ that is imposed in the diode gap. This finding highlights the importance of that region to diode designers

  20. Simulation and Analysis of Microwave Transmission through an Electron Cloud, a Comparison of Results

    International Nuclear Information System (INIS)

    Sonnad, Kiran; Sonnad, Kiran; Furman, Miguel; Veitzer, Seth; Stoltz, Peter; Cary, John

    2007-01-01

    Simulation studies for transmission of microwaves through electron clouds show good agreement with analytic results. The electron cloud produces a shift in phase of the microwave. Experimental observation of this phenomena would lead to a useful diagnostic tool for accessing the local density of electron clouds in an accelerator. These experiments are being carried out at the CERN SPS and the PEP-II LER at SLAC and is proposed to be done at the Fermilab main injector. In this study, a brief analysis of the phase shift is provided and the results are compared with that obtained from simulations

  1. Core size determination and structural characterization of intravenous iron complexes by cryogenic transmission electron microscopy.

    Science.gov (United States)

    Wu, Yong; Petrochenko, Peter; Chen, Lynn; Wong, Sook Yee; Absar, Mohammad; Choi, Stephanie; Zheng, Jiwen

    2016-05-30

    Understanding physicochemical properties of intravenous (IV) iron drug products is essential to ensure the manufacturing process is consistent and streamlined. The history of physicochemical characterization of IV iron complex formulations stretches over several decades, with disparities in iron core size and particle morphology as the major source of debate. One of the main reasons for this controversy is room temperature sample preparation artifacts, which affect accurate determination of size, shape and agglomeration/aggregation of nanoscale iron particles. The present study is first to report the ultra-fine iron core structures of four IV iron complex formulations, sodium ferric gluconate, iron sucrose, low molecular weight iron dextran and ferumoxytol, using a cryogenic transmission electron microscopy (cryo-TEM) preservation technique, as opposed to the conventional room temperature (RT-TEM) technique. Our results show that room temperature preparation causes nanoparticle aggregation and deformation, while cryo-TEM preserves IV iron colloidal suspension in their native frozen-hydrated and undiluted state. In contrast to the current consensus in literature, all four IV iron colloids exhibit a similar morphology of their iron oxide cores with a spherical shape, narrow size distribution and an average size of 2nm. Moreover, out of the four tested formulations, ferumoxytol exhibits a cluster-like community of several iron carbohydrate particles which likely accounts for its large hydrodynamic size of 25nm, measured with dynamic light scattering. Our findings outline a suitable method for identifying colloidal nanoparticle core size in the native state, which is increasingly important for manufacturing and design control of complex drug formulations, such as IV iron drug products. Published by Elsevier B.V.

  2. Testing aspects of advanced coherent electron cooling technique

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko, V.; Jing, Y.; Pinayev, I.; Wang, G.; Samulyak, R.; Ratner, D.

    2015-05-03

    An advanced version of the Coherent-electron Cooling (CeC) based on the micro-bunching instability was proposed. This approach promises significant increase in the bandwidth of the CeC system and, therefore, significant shortening of cooling time in high-energy hadron colliders. In this paper we present our plans of simulating and testing the key aspects of this proposed technique using the set-up of the coherent-electron-cooling proof-of-principle experiment at BNL.

  3. Ultrafast transmission electron microscopy using a laser-driven field emitter: Femtosecond resolution with a high coherence electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Feist, Armin; Bach, Nora; Rubiano da Silva, Nara; Danz, Thomas; Möller, Marcel; Priebe, Katharina E.; Domröse, Till; Gatzmann, J. Gregor; Rost, Stefan; Schauss, Jakob; Strauch, Stefanie; Bormann, Reiner; Sivis, Murat; Schäfer, Sascha, E-mail: sascha.schaefer@phys.uni-goettingen.de; Ropers, Claus, E-mail: claus.ropers@uni-goettingen.de

    2017-05-15

    We present the development of the first ultrafast transmission electron microscope (UTEM) driven by localized photoemission from a field emitter cathode. We describe the implementation of the instrument, the photoemitter concept and the quantitative electron beam parameters achieved. Establishing a new source for ultrafast TEM, the Göttingen UTEM employs nano-localized linear photoemission from a Schottky emitter, which enables operation with freely tunable temporal structure, from continuous wave to femtosecond pulsed mode. Using this emission mechanism, we achieve record pulse properties in ultrafast electron microscopy of 9 Å focused beam diameter, 200 fs pulse duration and 0.6 eV energy width. We illustrate the possibility to conduct ultrafast imaging, diffraction, holography and spectroscopy with this instrument and also discuss opportunities to harness quantum coherent interactions between intense laser fields and free-electron beams. - Highlights: • First implementation of an ultrafast TEM employing a nanoscale photocathode. • Localized single photon-photoemission from nanoscopic field emitter yields low emittance ultrashort electron pulses. • Electron pulses focused down to ~9 Å, with a duration of 200 fs and an energy width of 0.6 eV are demonstrated. • Quantitative characterization of ultrafast electron gun emittance and brightness. • A range of applications of high coherence ultrashort electron pulses is shown.

  4. Three-dimensional optical transfer functions in the aberration-corrected scanning transmission electron microscope.

    Science.gov (United States)

    Jones, L; Nellist, P D

    2014-05-01

    In the scanning transmission electron microscope, hardware aberration correctors can now correct for the positive spherical aberration of round electron lenses. These correctors make use of nonround optics such as hexapoles or octupoles, leading to the limiting aberrations often being of a nonround type. Here we explore the effect of a number of potential limiting aberrations on the imaging performance of the scanning transmission electron microscope through their resulting optical transfer functions. In particular, the response of the optical transfer function to changes in defocus are examined, given that this is the final aberration to be tuned just before image acquisition. The resulting three-dimensional optical transfer functions also allow an assessment of the performance of a system for focal-series experiments or optical sectioning applications. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

  5. Zinc deficiency in the 11 day rat embryo: a scanning and transmission electron microscope study

    Energy Technology Data Exchange (ETDEWEB)

    Harding, A.J.; Dreosti, I.E.; Tulsi, R.S.

    1988-01-01

    Zinc deficient rat embryos were obtained on the 11th day of pregnancy and examined by scanning and transmission electron microscopy. Scanning electron microscopy revealed an increase in the number of deformed embryos, as well as embryonic growth retardation. In addition, the epithelium of zinc deficient embryos displayed a marked increase in surface microvilli, as well as the presence of blebbing. Transmission electron microscopy indicated extensive cell death in the neural epithelium which was apparently more severely damaged by zinc deficiency than were mesenchymal cells. Mitochondrial cristae were affected to a greater degree than any other membrane of the cell and cristael disintegration appeared to represent the principal cellular lesion preceding necrosis of neural cells and neural tube teratology. 29 references, 4 figures, 1 table.

  6. Synthesis and Activation of Catalysts for Biofuel Synthesis in an Environmental Transmission Electron Microscope

    DEFF Research Database (Denmark)

    Duchstein, Linus Daniel Leonhard; Wu, Qiongxiao; Elkjær, Christian Fink

    of CuNi and NiGa catalysts for alcohol synthesis using High-Resolution TEM (HRTEM), energy electron-loss spectroscopy (EELS), Energy-Dispersive X-ray Spectroscopy (EDX). Complementary observations have been done using in-situ X-Ray Diffraction (XRD). We focus on structural changes during the catalysts...... synthesis and activation in a reducing atmosphere at elevated temperature. Changes in phase and particle size distribution with respect to the temperature can be directly observed and correlated to catalytic activity and integral phase information from the in-situ XRD....... promising candidates experimentally. Transmission electron microscopy (TEM) is used for microstructural characterization and provides feedback for both theory and synthesis. We have studied the catalysts close to their working conditions in an environmental transmission electron microscope (ETEM) equipped...

  7. An in-situ analytical scanning and transmission electron microscopy investigation of structure-property relationships in electronic materials

    Science.gov (United States)

    Wagner, Andrew James

    As electronic and mechanical devices are scaled downward in size and upward in complexity, macroscopic principles no longer apply. Synthesis of three-dimensionally confined structures exhibit quantum confinement effects allowing, for example, silicon nanoparticles to luminesce. The reduction in size of classically brittle materials reveals a ductile-to-brittle transition. Such a transition, attributed to a reduction in defects, increases elasticity. In the case of silicon, elastic deformation can improve electronic carrier mobility by over 50%, a vital attribute of modern integrated circuits. The scalability of such principles and the changing atomistic processes which contribute to them presents a vitally important field of research. Beginning with the direct observation of dislocations and lattice planes in the 1950s, the transmission electron microscope has been a powerful tool in materials science. More recently, as nanoscale technologies have proliferated modern life, their unique ability to spatially resolve nano- and atomic-scale structures has become a critical component of materials research and characterization. Signals produced by an incident beam of high-energy electrons enables researchers to both image and chemically analyze materials at the atomic scale. Coherently and elastically-scattered electrons can be collected to produce atomic-scale images of a crystalline sample. New specimen stages have enabled routine investigation of samples heated up to 1000 °C and cooled to liquid nitrogen temperatures. MEMS-based transducers allow for sub-nm scale mechanical testing and ultrathin membranes allow study of liquids and gases. Investigation of a myriad of previously "unseeable" processes can now be observed within the TEM, and sometimes something new is found within the old. High-temperature annealing of pure a Si:H films leads to crystallization of the film. Such films provide higher carrier mobility compared to amorphous films, offering improved

  8. Dose-rate-dependent damage of cerium dioxide in the scanning transmission electron microscope.

    Science.gov (United States)

    Johnston-Peck, Aaron C; DuChene, Joseph S; Roberts, Alan D; Wei, Wei David; Herzing, Andrew A

    2016-11-01

    Beam damage caused by energetic electrons in the transmission electron microscope is a fundamental constraint limiting the collection of artifact-free information. Through understanding the influence of the electron beam, experimental routines may be adjusted to improve the data collection process. Investigations of CeO 2 indicate that there is not a critical dose required for the accumulation of electron beam damage. Instead, measurements using annular dark field scanning transmission electron microscopy and electron energy loss spectroscopy demonstrate that the onset of measurable damage occurs when a critical dose rate is exceeded. The mechanism behind this phenomenon is that oxygen vacancies created by exposure to a 300keV electron beam are actively annihilated as the sample re-oxidizes in the microscope environment. As a result, only when the rate of vacancy creation exceeds the recovery rate will beam damage begin to accumulate. This observation suggests that dose-intensive experiments can be accomplished without disrupting the native structure of the sample when executed using dose rates below the appropriate threshold. Furthermore, the presence of an encapsulating carbonaceous layer inhibits processes that cause beam damage, markedly increasing the dose rate threshold for the accumulation of damage. Published by Elsevier B.V.

  9. Four-Dimensional Ultrafast Electron Microscopy: Insights into an Emerging Technique

    KAUST Repository

    Adhikari, Aniruddha

    2016-12-15

    Four-dimensional ultrafast electron microscopy (4D-UEM) is a novel analytical technique that aims to fulfill the long-held dream of researchers to investigate materials at extremely short spatial and temporal resolutions by integrating the excellent spatial resolution of electron microscopes with the temporal resolution of ultrafast femtosecond laser-based spectroscopy. The ingenious use of pulsed photoelectrons to probe surfaces and volumes of materials enables time-resolved snapshots of the dynamics to be captured in a way hitherto impossible by other conventional techniques. The flexibility of 4D-UEM lies in the fact that it can be used in both the scanning (S-UEM) and transmission (UEM) modes depending upon the type of electron microscope involved. While UEM can be employed to monitor elementary structural changes and phase transitions in samples using real-space mapping, diffraction, electron energy-loss spectroscopy, and tomography, S-UEM is well suited to map ultrafast dynamical events on materials surfaces in space and time. This review provides an overview of the unique features that distinguish these techniques and also illustrates the applications of both S-UEM and UEM to a multitude of problems relevant to materials science and chemistry.

  10. The study on surface characteristics of high transmission components by 3D printing technique

    Science.gov (United States)

    Kuo, Hui-Jean; Huang, Chien-Yao; Wang, Wan-Hsuan; Lin, Ping-Hung; Tsay, Ho-Lin; Hsu, Wei-Yao

    2017-06-01

    3D printing is a high freedom fabrication technique. Any components, which designed by 3D design software or scanned from real parts, can be printed. The printing materials include metals, plastics and biocompatible materials etc. Especially for those high transmission components used in optical system or biomedical field can be printed, too. High transmission lens increases the performances of optical system. And high transmission cover or shell using in biomedical field helps observers to see the structures inside, such as brain, bone, and vessels. But the surface of printed components is not transparent, even the inside layer is transparent. If we increase the transmittance of surface, the components which fabricated by 3D printing process could have high transmission. In this paper, we using illuminating and polishing methods to improve the transmittance of printing surface. The illuminating time is the experiment parameters in illuminating method. The roughness and transmission of printing components are the evaluating targets. A 3D printing machine, Stratasys Connex 500, has been used to print high transmittance components in this paper. The surface transmittance of printing components is increasing above 80 % by polishing method.

  11. Minerals and aligned collagen fibrils in tilapia fish scales: structural analysis using dark-field and energy-filtered transmission electron microscopy and electron tomography.

    Science.gov (United States)

    Okuda, Mitsuhiro; Ogawa, Nobuhiro; Takeguchi, Masaki; Hashimoto, Ayako; Tagaya, Motohiro; Chen, Song; Hanagata, Nobutaka; Ikoma, Toshiyuki

    2011-10-01

    The mineralized structure of aligned collagen fibrils in a tilapia fish scale was investigated using transmission electron microscopy (TEM) techniques after a thin sample was prepared using aqueous techniques. Electron diffraction and electron energy loss spectroscopy data indicated that a mineralized internal layer consisting of aligned collagen fibrils contains hydroxyapatite crystals. Bright-field imaging, dark-field imaging, and energy-filtered TEM showed that the hydroxyapatite was mainly distributed in the hole zones of the aligned collagen fibrils structure, while needle-like materials composed of calcium compounds including hydroxyapatite existed in the mineralized internal layer. Dark-field imaging and three-dimensional observation using electron tomography revealed that hydroxyapatite and needle-like materials were mainly found in the matrix between the collagen fibrils. It was observed that hydroxyapatite and needle-like materials were preferentially distributed on the surface of the hole zones in the aligned collagen fibrils structure and in the matrix between the collagen fibrils in the mineralized internal layer of the scale.

  12. On-line nuclear ash gauge for coal based on gamma-ray transmission techniques

    International Nuclear Information System (INIS)

    Rizk, R.A.M.; El-Kateb, A.H.; Abdul-Kader, A.M.

    1999-01-01

    Developments and applications of on-line nuclear gauges in the coal industry are highly requested. A nuclear ash gauge for coal, based on γ-ray transmission techniques is developed. Single and dual energy γ-ray beams are used to determine the ash content of coal. The percentage ash content as a function of the γ-ray intensities transmitted through coal samples is measured and sensitivity curves are obtained. An empirical formulation relating the ash content values to the γ-ray intensities is derived. Preliminary results show that both single and dual energy γ-ray transmission techniques can be used to give a rapid on-line estimation of the ash concentration values in coal with low cost and reasonable accuracy, but the dual one is much preferable. (author)

  13. Evaluation of Ultrasound-Induced Damage to Escherichia coli and Staphylococcus aureus by Flow Cytometry and Transmission Electron Microscopy.

    Science.gov (United States)

    Li, Jiao; Ahn, Juhee; Liu, Donghong; Chen, Shiguo; Ye, Xingqian; Ding, Tian

    2016-01-08

    As a nonthermal sterilization technique, ultrasound has attracted great interest in the field of food preservation. In this study, flow cytometry and transmission electron microscopy were employed to investigate ultrasound-induced damage to Escherichia coli and Staphylococcus aureus. For flow cytometry studies, single staining with propidium iodide (PI) or carboxyfluorescein diacetate (cFDA) revealed that ultrasound treatment caused cell death by compromising membrane integrity, inactivating intracellular esterases, and inhibiting metabolic performance. The results showed that ultrasound damage was independent of initial bacterial concentrations, while the mechanism of cellular damage differed according to the bacterial species. For the Gram-negative bacterium E. coli, ultrasound worked first on the outer membrane rather than the cytoplasmic membrane. Based on the double-staining results, we inferred that ultrasound treatment might be an all-or-nothing process: cells ruptured and disintegrated by ultrasound cannot be revived, which can be considered an advantage of ultrasound over other nonthermal techniques. Transmission electron microscopy studies revealed that the mechanism of ultrasound-induced damage was multitarget inactivation, involving the cell wall, cytoplasmic membrane, and inner structure. Understanding of the irreversible antibacterial action of ultrasound has great significance for its further utilization in the food industry. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  14. Power electronic converters PWM strategies and current control techniques

    CERN Document Server

    Monmasson, Eric

    2013-01-01

    A voltage converter changes the voltage of an electrical power source and is usually combined with other components to create a power supply. This title is devoted to the control of static converters, which deals with pulse-width modulation (PWM) techniques, and also discusses methods for current control. Various application cases are treated. The book is ideal for professionals in power engineering, power electronics, and electric drives industries, as well as practicing engineers, university professors, postdoctoral fellows, and graduate students.

  15. Atomic Metrology in Ordered/Disordered Systems Using Scanning Transmission Electron Microscopy

    Science.gov (United States)

    Oni, Adedapo Adesoji

    Electron microscopy has become a powerful tool for the characterization of material structure from the micron-scale to the Angstrom-scale. Notably, scanning transmission electron microscopy (STEM) with sub-Angstrom imaging capability provides access to atomic structure information. The latest STEMs equipped with small electron sources (Schottky or cold field emission gun), aberration-correctors, and improved electronic and mechanical stability enables spatial resolution better than 1 A. Herein, electron microscopy is utlized for structural and chemical atomic-scale characterization of ordered/disordered material systems. Structural quantification is commonly performed using spatially averaging approaches, such as X-ray or neutron diffraction. These techniques preclude real space analysis with local spatial sensitivity, e.g. across interfaces or at defects. In contrast, atomic resolution STEM enables direct imaging of the crystal structures, but until now, drift distortion has prevented accurate crystallographic measurements. Rather, the development of revolving STEM (RevSTEM) has enabled direct lattice parameter measurements to be performed across ordered/disordered systems using a probe{corrected scanning tranmission electron microscope with high accuracy and precision. Furthermore, the high spatial resolution of the probe-corrected STEM and advancement in the high sensitivity detector system owing to the state-of-the-art Super-X energy dispersive X-ray spectroscopy (EDS) detector enables simultaneous EDS elemental mapping at atomic resolution. Consequently, the site preference of solute atoms can be directly determined in the structure sublattice of the ordered intermetallic phase. Also, chemical segregation behavior of the constitutent elements within the microstructure are investigated using a combination of EDS and atom probe tomography (APT) analysis. In this dissertation, strain analysis was conducted across electron microscopy sample using multiple atomic

  16. Spherical aberration correction in a scanning transmission electron microscope using a sculpted thin film.

    Science.gov (United States)

    Shiloh, Roy; Remez, Roei; Lu, Peng-Han; Jin, Lei; Lereah, Yossi; Tavabi, Amir H; Dunin-Borkowski, Rafal E; Arie, Ady

    2018-03-27

    Nearly eighty years ago, Scherzer showed that rotationally symmetric, charge-free, static electron lenses are limited by an unavoidable, positive spherical aberration. Following a long struggle, a major breakthrough in the spatial resolution of electron microscopes was reached two decades ago by abandoning the first of these conditions, with the successful development of multipole aberration correctors. Here, we use a refractive silicon nitride thin film to tackle the second of Scherzer's constraints and demonstrate an alternative method for correcting spherical aberration in a scanning transmission electron microscope. We reveal features in Si and Cu samples that cannot be resolved in an uncorrected microscope. Our thin film corrector can be implemented as an immediate low cost upgrade to existing electron microscopes without re-engineering of the electron column or complicated operation protocols and can be extended to the correction of additional aberrations. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  17. Convergence des techniques de transmission fibre optique et radio MIMO haut débit

    OpenAIRE

    Dobremez, Vincent

    2013-01-01

    New technological uses such as cloud computing, smartphones, take part to the huge current increase of data consumption. This growth goes along with the development of optical networks, which will replace the copper networks with an higher and higher transmission capacity, thanks to new standards of fibers. This situation raises the question of the obsolete optical fibers reuse. It's shown in this thesis that MIMO techniques can be applied to multimode optical fibers in order to benefit from ...

  18. A study of growth and thermal dewetting behavior of ultra-thin gold films using transmission electron microscopy

    Directory of Open Access Journals (Sweden)

    Sudheer

    2017-07-01

    Full Text Available The growth and solid-state dewetting behavior of Au thin films (0.7 to 8.4 nm deposited on the formvar film (substrate by sputtering technique have been studied using transmission electron microscopy. The size and number density of the Au nanoparticles (NPs change with an increase in the film thickness (0.7 to 2.8 nm. Nearly spherical Au NPs are obtained for 6 nm show capability to be used as an irreversible temperature sensor with a sensitivity of ∼0.1 CAF/°C. It is observed that annealing affects the crystallinity of the Au grains in the films. The electron diffraction measurement also shows annealing induced morphological evolution in the percolated Au thin films (≥3 nm during solid-state dewetting and recrystallization of the grains.

  19. In vitro destruction of nerve cell cultures by Acanthamoeba spp.: a transmission and scanning electron microscopy study.

    Science.gov (United States)

    Pettit, D A; Williamson, J; Cabral, G A; Marciano-Cabral, F

    1996-10-01

    Trophozoites of 4 species of Acanthamoeba were cytopathic for cultured rat B103 neuroblastoma cells. Cytopathogenicity was evaluated by a chromium release assay and by transmission and scanning electron microscopy. Acanthamoeba culbertsoni, Acanthamoeba castellanii, and Acanthamoeba polyphaga destroyed B103 target cells at 37 C as evidenced by the release of radiolabel. Acanthamoeba astronyxis did not produce cytopathology at 37 C but destroyed nerve cells at 25 C. Transmission and scanning electron microscopy of cocultures maintained at different time periods revealed that all species of Acanthamoeba exhibited long cylindrical structures, termed digipodia, which made contact with target cells. Following this effector cell-target cell contact, membrane blebbing on the nerve cells was observed. These events were followed either by lysis of target nerve cells or ingestion of the target cells via food-cups and their subsequent channeling into intracytoplasmic food vacuoles. Use of the TUNEL (TdT-mediated dUTP nick end labeling) technique indicated that approximately 40% of B103 cells incubated with A. culbertsoni, 20% of B103 cells cocultured with A. castellanii or with A. polyphaga, and less than 1% of B103 cells incubated with A. astronyxis at 37 C were apoptotic after 24 hr of coculture. Studies using electron microscopy indicated that Acanthamoeba trophozoites destroyed nerve cells both by cytolysis and by ingestion of whole nerve cells via food-cups.

  20. Synthesis, structural analysis and in situ transmission electron microscopy mechanical tests on individual aluminum matrix/boron nitride nanotube nanohybrids

    International Nuclear Information System (INIS)

    Yamaguchi, Maho; Tang, Dai-Ming; Zhi Chunyi; Bando, Yoshio; Shtansky, Dmitry; Golberg, Dmitri

    2012-01-01

    Boron nitride nanotube (BNNT)/aluminum matrix composite nanohybrids were fabricated through magnetron sputtering of Al onto dispersed multiwalled BNNTs with average external diameters of 40–50 nm. Aluminum phase coating tightly wrapped the BNNTs after the deposition. The coating thickness in the range of 5–200 nm was controlled by changing sputtering time. Using imaging techniques and electron diffraction analysis in a transmission electron microscope, the Al phase was found to create nanocrystalline shields around individual BNNTs. The chemical states of the hybrid nanomaterials during the initial stages of sputtering were analyzed by X-ray photoelectron spectroscopy. Direct in situ bending and tensile tests on individual BNNT–Al nanocomposites were carried out by using a dedicated transmission electron microscope-atomic force microscope holder. In parallel, high-resolution TEM images and video recordings were taken for the analysis of deformation kinetics and fracture mechanisms. The nanohybrids with a suitably thick aluminum coating (∼40 nm) withstood at least nine times higher stresses compared to a pure non-armed Al metal. This pioneering work opens up a prospective pathway for making ultralight and superstrong “dream” structural materials for future automotive and aerospace applications.

  1. Weak-beam scanning transmission electron microscopy for quantitative dislocation density measurement in steels.

    Science.gov (United States)

    Yoshida, Kenta; Shimodaira, Masaki; Toyama, Takeshi; Shimizu, Yasuo; Inoue, Koji; Yoshiie, Toshimasa; Milan, Konstantinovic J; Gerard, Robert; Nagai, Yasuyoshi

    2017-04-01

    To evaluate dislocations induced by neutron irradiation, we developed a weak-beam scanning transmission electron microscopy (WB-STEM) system by installing a novel beam selector, an annular detector, a high-speed CCD camera and an imaging filter in the camera chamber of a spherical aberration-corrected transmission electron microscope. The capabilities of the WB-STEM with respect to wide-view imaging, real-time diffraction monitoring and multi-contrast imaging are demonstrated using typical reactor pressure vessel steel that had been used in an European nuclear reactor for 30 years as a surveillance test piece with a fluence of 1.09 × 1020 neutrons cm-2. The quantitatively measured size distribution (average loop size = 3.6 ± 2.1 nm), number density of the dislocation loops (3.6 × 1022 m-3) and dislocation density (7.8 × 1013 m m-3) were carefully compared with the values obtained via conventional weak-beam transmission electron microscopy studies. In addition, cluster analysis using atom probe tomography (APT) further demonstrated the potential of the WB-STEM for correlative electron tomography/APT experiments. © The Author 2017. 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.

  2. Assessing and ameliorating the influence of the electron beam on carbon nanotube oxidation in environmental transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Ai Leen, E-mail: alkoh@stanford.edu [Stanford Nano Shared Facilities, Stanford University, Stanford, CA 94305 (United States); Sinclair, Robert [Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305 (United States)

    2017-05-15

    In this work, we examine how the imaging electron beam can induce damage in carbon nanotubes (CNTs) at varying oxygen gas pressures and electron dose rates using environmental transmission electron microscopy (ETEM). Our studies show that there is a threshold cumulative electron dose which brings about damage in CNTs in oxygen – through removal of their graphitic walls – which is dependent on O{sub 2} pressure, with a 4–5 fold decrease in total electron dose per decade increase at a lower pressure range (10{sup −6} to 10{sup −5} mbar) and approximately 1.3 –fold decrease per decade increase at a higher pressure range (10{sup −3} to 10{sup 0} mbar). However, at a given pressure, damage in CNTs was found to occur even at the lowest dose rate utilized, suggesting the absence of a lower limit for the latter parameter. This study provides guidelines on the cumulative dose required to damage nanotubes in the 10{sup −7} mbar to 10{sup 0} mbar pressure regimes, and discusses the role of electron dose rate and total electron dose on beam-induced CNT degradation experiments. - Highlights: • The electron beam ionizes gas molecules in ETEM and affects experimental outcomes. • Beam-induced damage in CNTs occurs at varying O{sub 2} pressures and electron dose rates. • There is a threshold cumulative dose to damage CNTs which depends on O{sub 2} pressure. • At a given pressure, CNT damage occurs even at the electron dose rate utilized.

  3. Multiphoton electronic-spin generation and transmission spectroscopy in n-type GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Idrish Miah, M., E-mail: m.miah@griffith.edu.a [Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh)

    2011-01-17

    Multiphoton electronic-spin generation in semiconductors was investigated using differential transmission spectroscopy. The generation of the electronic spins in the semiconductor samples were achieved by multiphoton pumping with circularly polarized light beam and was probed by the spin-resolved transmission of the samples. The electronic spin-polarization of conduction band was estimated and was found to depend on the delay of the probe beam, temperature as well as on the multiphoton pumping energy. The temperature dependence showed a decrease of the spin-polarization with increasing temperature. The electronic spin-polarization was found to depolarize rapidly for multiphoton pumping energy larger than the energy gap of the split-off band to the conduction band. The results were compared with those obtained in one-photon pumping, which shows that an enhancement of the electronic spin-polarization was achieved in multiphoton pumping. The findings resulting from this investigation might have potential applications in opto-spintronics, where the generation of highly polarized electronic spins is required.

  4. Multiphoton electronic-spin generation and transmission spectroscopy in n-type GaAs

    International Nuclear Information System (INIS)

    Idrish Miah, M.

    2011-01-01

    Multiphoton electronic-spin generation in semiconductors was investigated using differential transmission spectroscopy. The generation of the electronic spins in the semiconductor samples were achieved by multiphoton pumping with circularly polarized light beam and was probed by the spin-resolved transmission of the samples. The electronic spin-polarization of conduction band was estimated and was found to depend on the delay of the probe beam, temperature as well as on the multiphoton pumping energy. The temperature dependence showed a decrease of the spin-polarization with increasing temperature. The electronic spin-polarization was found to depolarize rapidly for multiphoton pumping energy larger than the energy gap of the split-off band to the conduction band. The results were compared with those obtained in one-photon pumping, which shows that an enhancement of the electronic spin-polarization was achieved in multiphoton pumping. The findings resulting from this investigation might have potential applications in opto-spintronics, where the generation of highly polarized electronic spins is required.

  5. Development techniques and electron optical studies of high voltage, high current electron guns

    International Nuclear Information System (INIS)

    Rangarajan, L.M.; Mahadevan, S.; Ramamurthi, S.S.

    1992-01-01

    The progress of the electron gun design, limiting to axially symmetric geometries is discussed here with a view to utilise such guns for electron accelerators. The mechanical design features leading to the physical configuration of the gun with stringent tolerances are outlined. Vacuum processing is done at pressures of 1.3x10 -5 Pa. The gun employs W-filament emitter or a cathode pellet with bombarder service. A water cooled compact faraday cup is used to measure the electron current. Electron gun geometries have been studied using the computer programme. The preveance of the gun is 0.7x10 -7 A/Vsup(1.5) at 80 kV. Developmental techniques of such pulsed electron guns are described. (author). 7 refs., 5 figs

  6. 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

  7. Specimen-thickness effects on transmission Kikuchi patterns in the scanning electron microscope.

    Science.gov (United States)

    Rice, K P; Keller, R R; Stoykovich, M P

    2014-06-01

    We report the effects of varying specimen thickness on the generation of transmission Kikuchi patterns in the scanning electron microscope. Diffraction patterns sufficient for automated indexing were observed from films spanning nearly three orders of magnitude in thickness in several materials, from 5 nm of hafnium dioxide to 3 μm of aluminum, corresponding to a mass-thickness range of ~5 to 810 μg cm(-2) . The scattering events that are most likely to be detected in transmission are shown to be very near the exit surface of the films. The energies, spatial distribution and trajectories of the electrons that are transmitted through the film and are collected by the detector are predicted using Monte Carlo simulations. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  8. A nanocrystalline Hilbert phase-plate for phase-contrast transmission electron microscopy.

    Science.gov (United States)

    Dries, M; Hettler, S; Gamm, B; Müller, E; Send, W; Müller, K; Rosenauer, A; Gerthsen, D

    2014-04-01

    Thin-film-based phase-plates are applied to enhance the contrast of weak-phase objects in transmission electron microscopy. In this work, metal-film-based phase-plates are considered to reduce contamination and electrostatic charging, which up to now limit the application of phase-plates fabricated from amorphous C-films. Their crystalline structure requires a model for the simulation of the effect of crystallinity on the phase-plate properties and the image formation process. The model established in this work is verified by experimental results obtained by the application of a textured nanocrystalline Au-film-based Hilbert phase-plate. Based on the model, it is shown that monocrystalline and textured nanocrystalline phase-plate microstructures of appropriate thickness and crystalline orientation can be a promising approach for phase-contrast transmission electron microscopy. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. 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.)

  10. Characterisation of nanovoiding in dental porcelain using small angle neutron scattering and transmission electron microscopy.

    Science.gov (United States)

    Lunt, Alexander; Terry, Ann; Ying, Siqi; Baimpas, Nikolaos; Sui, Tan; Kabra, Saurabh; Kelleher, Joe; King, Stephen; Khin, Neo Tee; Korsunsky, Alexander M

    2017-05-01

    Recent studies of the yttria partially stabilised zirconia-porcelain interface have revealed the presence of near-interface porcelain nanovoiding which reduces toughness and leads to component failure. One potential explanation for these nanoscale features is thermal creep which is induced by the combination of the residual stresses at the interface and sintering temperatures applied during manufacture. The present study provides improved understanding of this important phenomenon. Transmission electron microscopy and small angle neutron scattering were applied to a sample which was crept at 750°C and 100MPa (sample C), a second which was exposed to an identical heat treatment schedule in the absence of applied stress (sample H), and a reference sample in the as-machined state (sample A). The complementary insights provided by the two techniques were in good agreement and log-normal void size distributions were found in all samples. The void number density was found to be 1.61μm -2 , 25.4μm -2 and 98.6μm -2 in samples A, H and C respectively. The average void diameter in sample A (27.1nm) was found to be more than twice as large as in samples H (10.2nm) and C (11.6nm). The crept data showed the highest skewness parameter (2.35), indicating stress-induced growth of larger voids and void coalescence that has not been previously observed. The improved insight presented in this study can be integrated into existing models of dental prostheses in order to optimise manufacturing routes and thereby reduce the significant detrimental impact of this nanostructural phenomenon. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  11. Irradiation-related amorphization and crystallization: In situ transmission electron microscope studies

    International Nuclear Information System (INIS)

    Allen, C.W.

    1994-01-01

    Interfacing an ion accelerator to a transmission electron microscope (TEM) allows the analytical functions of TEM imaging and diffraction to be employed during ion-irradiation effects studies. At present there are twelve such installations in Japan, one in France and one in the US. This paper treats several aspects of in situ studies involving electron and ion beam induced and enhanced phase transformations and presents results of several in situ experiments to illustrate the dynamics of this approach in the materials science of irradiation effects. The paper describes the ion- and electron-induced amorphization of CuTi; the ion-irradiation-enhanced transformation of TiCr 2 ; and the ion- and electron-irradiation-enhanced crystallization of CoSi 2

  12. In situ measurements and transmission electron microscopy of carbon nanotube field-effect transistors

    International Nuclear Information System (INIS)

    Kim, Taekyung; Kim, Seongwon; Olson, Eric; Zuo Jianmin

    2008-01-01

    We present the design and operation of a transmission electron microscopy (TEM)-compatible carbon nanotube (CNT) field-effect transistor (FET). The device is configured with microfabricated slits, which allows direct observation of CNTs in a FET using TEM and measurement of electrical transport while inside the TEM. As demonstrations of the device architecture, two examples are presented. The first example is an in situ electrical transport measurement of a bundle of carbon nanotubes. The second example is a study of electron beam radiation effect on CNT bundles using a 200 keV electron beam. In situ electrical transport measurement during the beam irradiation shows a signature of wall- or tube-breakdown. Stepwise current drops were observed when a high intensity electron beam was used to cut individual CNT bundles in a device with multiple bundles

  13. Graphene as a transparent conductive support for studying biological molecules by transmission electron microscopy

    International Nuclear Information System (INIS)

    Nair, R. R.; Anissimova, S.; Novoselov, K. S.; Blake, P.; Blake, J. R.; Geim, A. K.; Zan, R.; Bangert, U.; Golovanov, A. P.; Morozov, S. V.; Latychevskaia, T.

    2010-01-01

    We demonstrate the application of graphene as a support for imaging individual biological molecules in transmission electron microscope (TEM). A simple procedure to produce free-standing graphene membranes has been designed. Such membranes are extremely robust and can support practically any submicrometer object. Tobacco mosaic virus has been deposited on graphene samples and observed in a TEM. High contrast has been achieved even though no staining has been applied.

  14. The Physical Characterization of Liposome Salicylic Acid Using Transmission Electron Microscope

    International Nuclear Information System (INIS)

    Elman Panjaitan

    2008-01-01

    The physical characterization of liposome, formulated from salicylic acid using thin film hydration methods with cholesterol and soybean lecithin, has been done. The formula was characterized by optical microscopes and Transmission Electron Microscope (TEM). The observation result shows that the salicylic acid can be formulated to liposomes. Soybean lecithin combined with cholesterol (600 mg : 20 mg) was the best formula and the liposome was spherical vesicle like with dimension about 70 nm unit 800 nm. (author)

  15. Nanoparticle sizing: a comparative study using atomic force microscopy, transmission electron microscopy, and ferromagnetic resonance

    International Nuclear Information System (INIS)

    Lacava, L.M.; Lacava, B.M.; Azevedo, R.B.; Lacava, Z.G.M.; Buske, N.; Tronconi, A.L.; Morais, P.C.

    2001-01-01

    Atomic force microscopy (AFM), transmission electron microscopy (TEM), and ferromagnetic resonance (FMR) were used to unfold the nanoparticle size of a ferrofluid sample. Compared to TEM, the AFM method showed a nanoparticle diameter (D m ) reduction of 20% and standard deviation (σ) increase of 15%. The differences in D m and σ were associated with the AFM tip and the nanoparticle concentration on the substrate

  16. Advanced scanning transmission stereo electron microscopy of structural and functional engineering materials

    Czech Academy of Sciences Publication Activity Database

    Agudo Jácome, L.; Eggeler, G.; Dlouhý, Antonín

    2012-01-01

    Roč. 122, NOV (2012), s. 48-59 ISSN 0304-3991 R&D Projects: GA ČR GA202/09/2073 Institutional research plan: CEZ:AV0Z20410507 Keywords : stereoscopy * scanning transmission electron microscopy * single crystal Ni-base superalloys * Dislocation substructures * Foil thickness measurement Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.470, year: 2012

  17. A transmission electron microscopy procedure for in-situ straining of miniature

    Czech Academy of Sciences Publication Activity Database

    Olbricht, J.; Wagner, M. F- X.; Condó, A.; Dlouhý, Antonín; Grossman, Ch.; Kröger, A.; Somsen, Ch.; Eggeler, G.

    2008-01-01

    Roč. 99, č. 10 (2008), s. 1150-1156 ISSN 1862-5282 R&D Projects: GA ČR(CZ) GA106/05/0918 Institutional research plan: CEZ:AV0Z20410507 Keywords : transmission electron microscopy * in-situ straining * nano-crystalline NiTi Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.819, year: 2008

  18. Preparation of Cells for Assessing Ultrastructural Localization of Nanoparticles with Transmission Electron Microscopy

    Science.gov (United States)

    2010-01-01

    SUBTITLE Preparation of cells for assessing ultrastructural localization of nanoparticles with transmission electron microscopy 5a. CONTRACT NUMBER...a–h). Plate and grow cells (a), prepare nanoparticle (NP)-dosing solutions (b), dose cells with NPs (c), cell processing (d), resin embedding and...modification of monodisperse magnetite nanoparticles for improved intracellular uptake to breast cancer cells. J. Colloid Interface Sci. 283, 352–357

  19. Studying the Kinetics of Crystalline Silicon Nanoparticle Lithiation with In Situ Transmission Electron Microscopy

    KAUST Repository

    McDowell, Matthew T.

    2012-09-04

    In situ transmission electron microscopy (TEM) is used to study the electrochemical lithiation of high-capacity crystalline Si nanoparticles for use in Li-ion battery anodes. The lithiation reaction slows down as it progresses into the particle interior, and analysis suggests that this behavior is due not to diffusion limitation but instead to the influence of mechanical stress on the driving force for reaction. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Reliable strain measurement in transistor arrays by robust scanning transmission electron microscopy

    Directory of Open Access Journals (Sweden)

    Suhyun Kim

    2013-09-01

    Full Text Available Accurate measurement of the strain field in the channels of transistor arrays is critical for strain engineering in modern electronic devices. We applied atomic-resolution high-angle annular dark-field scanning transmission electron microscopy to quantitative measurement of the strain field in transistor arrays. The quantitative strain profile over 20 transistors was obtained with high reliability and a precision of 0.1%. The strain field was found to form homogeneously in the channels of the transistor arrays. Furthermore, strain relaxation due to the thin foil effect was quantitatively investigated for thicknesses of 35 to 275 nm.

  1. The Fresnel mode of Lorentz microscopy using a scanning transmission electron microscope

    International Nuclear Information System (INIS)

    Chapman, J.N.; Waddell, E.M.; Batson, P.E.; Ferrier, R.P.

    1979-01-01

    The most widely used method of investigating ferromagnetic films in the transmission electron microscope is the Fresnel or defocus mode of Lorentz microscopy. This may be implemented either in a fixed beam or a scanning instrument. Despite a rather inefficient utilization of electrons, several advantages accrue if the latter is used, and provided it is equipped with a field emission gun, low noise images may be obtained in acceptable recording times. To extract quantitative estimates of domain wall widths from such images it is necessary to measure accurately both instrumental and specimen parameters. Methods for this are discussed and an example of an analysis using a polycrystalline permalloy film is given. (Auth.)

  2. Employing NMR Spectroscopy To Evaluate Transmission of Electronic Effects in 4-Substituted Chalcones

    Science.gov (United States)

    Wachter-Jurcsak, Nanette; Zamani, Hossein

    1999-05-01

    Described is an organic synthesis experiment that demonstrates the electronic transmission by substituents. The effect of substitution at the para-position of the styryl ring of 1,3-diphenyl-2-propenones (chalcones) by typical electron-donating or -accepting groups can be observed by proton and carbon-13 NMR spectroscopy. A linear correlation is observed when the differences in chemical shift measurements for H are plotted against the corresponding Hammett substituent constant values. Good correlation between carbon-13 chemical shifts of the alpha carbon are also observed. The syntheses of the 4-substituted chalcones is presented as well as a brief discussion of the theory.

  3. Transmission electron microscopic method for gene mapping on polytene chromosomes by in situ hybridization

    OpenAIRE

    Wu, Madeline; Davidson, Norman

    1981-01-01

    A transmission electron microscope method for gene mapping by in situ hybridization to Drosophila polytene chromosomes has been developed. As electron-opaque labels, we use colloidal gold spheres having a diameter of 25 nm. The spheres are coated with a layer of protein to which Escherichia coli single-stranded DNA is photochemically crosslinked. Poly(dT) tails are added to the 3' OH ends of these DNA strands, and poly(dA) tails are added to the 3' OH ends of a fragmented cloned Drosophila DN...

  4. Nanosecond time-resolved investigations using the in situ of dynamic transmission electron microscope (DTEM)

    International Nuclear Information System (INIS)

    LaGrange, Thomas; Campbell, Geoffrey H.; Reed, B.W.; Taheri, Mitra; Pesavento, J. Bradley; Kim, Judy S.; Browning, Nigel D.

    2008-01-01

    Most biological processes, chemical reactions and materials dynamics occur at rates much faster than can be captured with standard video rate acquisition methods in transmission electron microscopes (TEM). Thus, there is a need to increase the temporal resolution in order to capture and understand salient features of these rapid materials processes. This paper details the development of a high-time resolution dynamic transmission electron microscope (DTEM) that captures dynamics in materials with nanosecond time resolution. The current DTEM performance, having a spatial resolution <10 nm for single-shot imaging using 15 ns electron pulses, will be discussed in the context of experimental investigations in solid state reactions of NiAl reactive multilayer films, the study of martensitic transformations in nanocrystalline Ti and the catalytic growth of Si nanowires. In addition, this paper will address the technical issues involved with high current, electron pulse operation and the near-term improvements to the electron optics, which will greatly improve the signal and spatial resolutions, and to the laser system, which will allow tailored specimen and photocathode drive conditions

  5. Electronic transmission through p-n and n-p-n junctions of graphene

    Energy Technology Data Exchange (ETDEWEB)

    Setare, M R [Department of Science of Bijar, University of Kurdistan, Bijar (Iran, Islamic Republic of); Jahani, D, E-mail: rezakord@ipm.co, E-mail: Dariush110@gmail.co [Department of Physics, Razi University, Kermanshah (Iran, Islamic Republic of)

    2010-06-23

    In this paper, we first evaluate the electronic transmission of Dirac fermions into a p-n junction of gapped graphene and show that the final result depends on the sign of the refractive index, n. We also, by considering the appropriate wavefunctions in the region of the electrostatic potential, show that both transmission and the reflection probability turn out to be positive and less than unity instead of the negative transmission and higher than unity reflection coefficient commonly referred to as the Klein paradox. We then obtain the transmission probability corresponding to a special p-n junction for which there exists a region in which the low energy excitations of graphene acquire a finite mass and, interestingly, find that in this case the transmission is independent of the index of refraction, in contrast with the corresponding result for gapped graphene. We then discuss the validity of the solutions reported in some of the papers cited in this work which, considering the Buettiker formula, turn out to lead to the wrong results for conductivity.

  6. Transmission dosimetry with a liquid-filled electronic portal imaging device

    Energy Technology Data Exchange (ETDEWEB)

    Boellaard, R.; Van Herk, M.; Mijnheer, B.J. [Nederlands Kanker Inst. `Antoni van Leeuwenhoekhuis`, Amsterdam (Netherlands)

    1995-12-01

    The aim of transmission dosimetry is to correlate transmission dose values with patient dose values. A liquid-filled electronic portal imaging device (EPID) has been developed. After determination of the dose response relationship, i.e. the relation between pixel value and dose rate, for clinical situations it was found that the EPID is applicable for two-dimensional dosimetry with an accuracy of about 1%. The aim of this study was to investigate transmission dose distributions at different phantom-detector distances to predict exit dose distributions from transmission dose images. An extensive set of transmission dose measurements below homogeneous phantoms were performed with the EPID. The influence of several parameters such as field size, phantom thickness, phantom-detector distance and phantom-source distance on the transmission dose and its distribution were investigated. The two-dimensional transmission dose images were separated into two components: a primary dose and a scattered dose distribution. It was found that the scattered dose is maximal at a phantom thickness of about 10 cm. The scattered dose distribution below a homogeneous phantom has a Gaussian shape. The width of the Gaussian is small at small phantom-detector distances and increases for larger phantom-detector distances. The dependence of the scattered dose distribution on the field size at various phantom-detector distances has been used to estimate the dose distribution at the exit site of the phantom. More work is underway to determine the exit dose distributions for clinical situations, including the presence of inhomogeneities.

  7. Transmission dosimetry with a liquid-filled electronic portal imaging device

    International Nuclear Information System (INIS)

    Boellaard, R.; Van Herk, M.; Mijnheer, B.J.

    1995-01-01

    The aim of transmission dosimetry is to correlate transmission dose values with patient dose values. A liquid-filled electronic portal imaging device (EPID) has been developed. After determination of the dose response relationship, i.e. the relation between pixel value and dose rate, for clinical situations it was found that the EPID is applicable for two-dimensional dosimetry with an accuracy of about 1%. The aim of this study was to investigate transmission dose distributions at different phantom-detector distances to predict exit dose distributions from transmission dose images. An extensive set of transmission dose measurements below homogeneous phantoms were performed with the EPID. The influence of several parameters such as field size, phantom thickness, phantom-detector distance and phantom-source distance on the transmission dose and its distribution were investigated. The two-dimensional transmission dose images were separated into two components: a primary dose and a scattered dose distribution. It was found that the scattered dose is maximal at a phantom thickness of about 10 cm. The scattered dose distribution below a homogeneous phantom has a Gaussian shape. The width of the Gaussian is small at small phantom-detector distances and increases for larger phantom-detector distances. The dependence of the scattered dose distribution on the field size at various phantom-detector distances has been used to estimate the dose distribution at the exit site of the phantom. More work is underway to determine the exit dose distributions for clinical situations, including the presence of inhomogeneities

  8. Quantum coherent optical phase modulation in an ultrafast transmission electron microscope.

    Science.gov (United States)

    Feist, Armin; Echternkamp, Katharina E; Schauss, Jakob; Yalunin, Sergey V; Schäfer, Sascha; Ropers, Claus

    2015-05-14

    Coherent manipulation of quantum systems with light is expected to be a cornerstone of future information and communication technology, including quantum computation and cryptography. The transfer of an optical phase onto a quantum wavefunction is a defining aspect of coherent interactions and forms the basis of quantum state preparation, synchronization and metrology. Light-phase-modulated electron states near atoms and molecules are essential for the techniques of attosecond science, including the generation of extreme-ultraviolet pulses and orbital tomography. In contrast, the quantum-coherent phase-modulation of energetic free-electron beams has not been demonstrated, although it promises direct access to ultrafast imaging and spectroscopy with tailored electron pulses on the attosecond scale. Here we demonstrate the coherent quantum state manipulation of free-electron populations in an electron microscope beam. We employ the interaction of ultrashort electron pulses with optical near-fields to induce Rabi oscillations in the populations of electron momentum states, observed as a function of the optical driving field. Excellent agreement with the scaling of an equal-Rabi multilevel quantum ladder is obtained, representing the observation of a light-driven 'quantum walk' coherently reshaping electron density in momentum space. We note that, after the interaction, the optically generated superposition of momentum states evolves into a train of attosecond electron pulses. Our results reveal the potential of quantum control for the precision structuring of electron densities, with possible applications ranging from ultrafast electron spectroscopy and microscopy to accelerator science and free-electron lasers.

  9. Electron tomography based on a total variation minimization reconstruction technique

    Energy Technology Data Exchange (ETDEWEB)

    Goris, B., E-mail: bart.goris@ua.ac.be [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Van den Broek, W. [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Batenburg, K.J. [Centrum Wiskunde and Informatica, Science Park 123, NL-1098XG Amsterdam (Netherlands); Vision Lab, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk (Belgium); Heidari Mezerji, H.; Bals, S. [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)

    2012-02-15

    The 3D reconstruction of a tilt series for electron tomography is mostly carried out using the weighted backprojection (WBP) algorithm or using one of the iterative algorithms such as the simultaneous iterative reconstruction technique (SIRT). However, it is known that these reconstruction algorithms cannot compensate for the missing wedge. Here, we apply a new reconstruction algorithm for electron tomography, which is based on compressive sensing. This is a field in image processing specialized in finding a sparse solution or a solution with a sparse gradient to a set of ill-posed linear equations. Therefore, it can be applied to electron tomography where the reconstructed objects often have a sparse gradient at the nanoscale. Using a combination of different simulated and experimental datasets, it is shown that missing wedge artefacts are reduced in the final reconstruction. Moreover, it seems that the reconstructed datasets have a higher fidelity and are easier to segment in comparison to reconstructions obtained by more conventional iterative algorithms. -- Highlights: Black-Right-Pointing-Pointer A reconstruction algorithm for electron tomography is investigated based on total variation minimization. Black-Right-Pointing-Pointer Missing wedge artefacts are reduced by this algorithm. Black-Right-Pointing-Pointer The reconstruction is easier to segment. Black-Right-Pointing-Pointer More reliable quantitative information can be obtained.

  10. Electronic structure analyses of BN network materials using high energy-resolution spectroscopy methods based on transmission electron microscopy.

    Science.gov (United States)

    Terauchi, M

    2006-07-01

    Electronic structures of boron-nitride (BN) nanotubes and a BN cone-structure material were studied by using a high energy-resolution electron energy-loss spectroscopy (EELS) microscope. A trial of the whole electronic structure study of hexagonal BN (h-BN), which consists of flat BN honeycomb layers, was conducted by a combination of EELS and X-ray emission spectroscopy (XES) based on transmission electron microscopy (TEM) (TEM-EELS/XES). The pi and pi+sigma plasmon energies of BN nanotubes (BNT) were smaller than those of h-BN. The pi+sigma energy was explained by the surface plasmon excitation. The spectrum of a two-wall BNT of 2.7 nm in diameter showed a new spectral onset at 4 eV. The valence electron excitation spectra obtained from the tip region of the BN cone with an apex angle of 20 degrees showed similar intensity distribution with those of BNTs. The B K-shell electron excitation spectra obtained from the bottom edge region of the BN cone showed additional peak intensity when compared with those of h-BN and BNT. The B K-shell electron excitation spectra and B K-emission spectra of h-BN were compared with a result of a LDA band calculation. It showed that high symmetry points in the band diagram appear as peak and/or shoulder structures in the EELS and XES spectra. Interband transitions appeared in the imaginary part of the dielectric function of h-BN experimentally obtained were assigned in the band diagram. The analysis also presented that the LDA calculation estimated the bandgap energy smaller than the real material by an amount of 2 eV. Those results of TEM-EELS/XES analysis presented that high energy-resolution spectroscopy methods combined with TEM is a promising method to analyze whole electronic structures of nanometer scale materials. Copyright (c) 2006 Wiley-Liss, Inc.

  11. Electronic properties of Be and Al by Compton scattering technique

    International Nuclear Information System (INIS)

    Aguiar, J.C.; Di Rocco, H.O.

    2011-01-01

    In this work, electronic properties of beryllium and aluminum are examined by using Compton scattering technique. The method is based on the irradiation of samples using a beam narrow of mono- energetic photons of 59.54 keV product of radioactive decay of Am -241 . Scattered radiation is collected by a high resolution semiconductor detector positioned at an angle of 90°. The measured spectrum is commonly called Compton profile and contains useful information about the electronic structure of the material. The experimental results are compared with theoretical calculations such as density functional theory showing a good agreement. However, these results show some discrepancies with many libraries used in codes such as Monte Carlo simulation. Since these libraries are based on the values tabulated by Biggs, Mendelsohn and Mann 1975 thus overestimating the scattered radiation on the material. (authors) [es

  12. DEVELOPMENT OF WIRELESS TECHNIQUES IN DATA AND POWER TRANSMISSION APPLICATION FOR PARTICLE-PHYSICS DETECTORS

    CERN Document Server

    Brenner, R; Dehos, C; De Lurgio, P; Djurcic, Z; Drake, G; Gonzales Gimenez, JL; Gustafsson, L; Kim, DW; Locci, E; Pfeiffer, U; Röhrich, D; Rydberg, D; Schöning, A; Siligaris, A; Soltveit, HK; Ullaland, K; Vincent, P; Vasquez, PR; Wiedner, D; Yang, S

    2017-01-01

    In the WADAPT project described in this Letter of Intent, we propose to develop wireless techniques for data and power transmission in particle-physics detectors. Wireless techniques have developed extremely fast over the last decade and are now mature for being considered as a promising alternative to cables and optical links that would revolutionize the detector design. The WADAPT consortium has been formed to identify the specific needs of different projects that might benefit from wireless techniques with the objective of providing a common platform for research and development in order to optimize effectiveness and cost. The proposed R&D will aim at designing and testing wireless demonstrators for large instrumentation systems.

  13. Linear least-squares fit evaluation of series of analytical spectra from planar defects: extension and possible implementations in scanning transmission electron microscopy.

    Science.gov (United States)

    Walther, T

    2006-08-01

    In a previous paper, a new technique was introduced to determine the chemistry of crystallographically well-defined planar defects (such as straight interfaces, grain boundaries, twins, inversion or antiphase domain boundaries) in the presence of homogeneous solute segregation or selective doping. The technique is based on a linear least-squares fit using series of analytical (electron energy-loss or energy-dispersive X-ray) spectra acquired in a transmission electron microscope that is operated in nano-probe mode with the planar defect centred edge-on. First, additional notes on the use of proper k-factors and determination of Gibbsian excess segregation are given in this note. Using simulated data sets, it is shown that the linear least-squares fit improves both the accuracy and the robustness to noise beyond that obtainable by independently repeated measurements. It is then shown how the method originally developed for a stationary nano-probe mode in transmission electron microscopy can be extended to a focused electron beam that scans a square region in scanning transmission electron microscopy. The necessary modifications to scan geometry and corresponding numerical evaluation are described, and three different practical implementations are proposed.

  14. Sample Preparation Methodologies for In Situ Liquid and Gaseous Cell Analytical Transmission Electron Microscopy of Electropolished Specimens.

    Science.gov (United States)

    Zhong, Xiang Li; Schilling, Sibylle; Zaluzec, Nestor J; Burke, M Grace

    2016-12-01

    In recent years, an increasing number of studies utilizing in situ liquid and/or gaseous cell scanning/transmission electron microscopy (S/TEM) have been reported. Because of the difficulty in the preparation of suitable specimens, these environmental S/TEM studies have been generally limited to studies of nanoscale structured materials such as nanoparticles, nanowires, or sputtered thin films. In this paper, we present two methodologies which have been developed to facilitate the preparation of electron-transparent samples from conventional bulk metals and alloys for in situ liquid/gaseous cell S/TEM experiments. These methods take advantage of combining sequential electrochemical jet polishing followed by focused ion beam extraction techniques to create large electron-transparent areas for site-specific observation. As an example, we illustrate the application of this methodology for the preparation of in situ specimens from a cold-rolled Type 304 austenitic stainless steel sample, which was subsequently examined in both 1 atm of air as well as fully immersed in a H2O environment in the S/TEM followed by hyperspectral imaging. These preparation techniques can be successfully applied as a general procedure for a wide range of metals and alloys, and are suitable for a variety of in situ analytical S/TEM studies in both aqueous and gaseous environments.

  15. In situ transmission electron microscopy analysis of electron beam induced crystallization of amorphous marks in phase-change materials

    International Nuclear Information System (INIS)

    Kaiser, M.; Pieterson, L. van; Verheijen, M.A.

    2004-01-01

    Crystallization of amorphous data marks in crystalline Ga 15 Sb 85 and Ge,In doped SbTe phase-change material was studied in situ in a Transmission Electron Microscope (TEM). Electron irradiation induced crystallization was obtained at room temperature using a 120 kV beam. In general, electron beam (e - beam) induced crystallization started from the amorphous-crystalline interface and was growth dominated for both materials. A dependence of growth velocity on electron beam intensity and crystal direction was observed. A comparison with laser-crystallized amorphous marks was made. For laser-induced crystallization also crystal growth from the amorphous-crystalline interface was seen. However, differences in morphology between the e - -beam and laser-recrystallized data marks of the GaSb phase-change material were observed. The electron beam erased data marks contained crystals with (extremely) large periodicities found in three dimensions. For the Ge,In doped SbTe phase-change material identical morphologies were observed for the e - -beam and laser-recrystallized data marks. Both methods that induce crystallization displayed a rhombohedral Sb structure, the same structure as the laser-crystallized surroundings

  16. The thin layer technique and its application to electron microscopy

    International Nuclear Information System (INIS)

    Ranc, G.

    1957-10-01

    This work deals with the technique of thin layers obtained by evaporation under vacuum, in the thickness range extending from a few monoatomic layers to several hundred angstroms. The great theoretical and practical interest of these layers has, it is well known, given rise to many investigations from Faraday onwards. Within the necessarily restricted limits of this study, we shall approach the problem more particularly from the point of view of: - their production; - their use in electron microscopy. A critical appraisal is made, in the light of present-day knowledge, based on our personal experience and on an extensive bibliography which we have collected on the subject. (author) [fr

  17. Elucidation of crystal and electronic structures within highly strained BiFeO3by transmission electron microscopy and first-principles simulation.

    Science.gov (United States)

    Bae, In-Tae; Kovács, András; Zhao, Hong Jian; Íñiguez, Jorge; Yasui, Shintaro; Ichinose, Tomohiro; Naganuma, Hiroshi

    2017-04-19

    Crystal and electronic structures of ~380 nm BiFeO 3 film grown on LaAlO 3 substrate are comprehensively studied using advanced transmission electron microscopy (TEM) technique combined with first-principles theory. Cross-sectional TEM images reveal the BiFeO 3 film consists of two zones with different crystal structures. While zone II turns out to have rhombohedral BiFeO 3 , the crystal structure of zone I matches none of BiFeO 3 phases reported experimentally or predicted theoretically. Detailed electron diffraction analysis combined with first-principles calculation allows us to determine that zone I displays an orthorhombic-like monoclinic structure with space group of Cm (=8). The growth mechanism and electronic structure in zone I are further discussed in comparison with those of zone II. This study is the first to provide an experimentally validated complete crystallographic detail of a highly strained BiFeO 3 that includes the lattice parameter as well as the basis atom locations in the unit cell.

  18. Characterization of electron clouds in the Cornell Electron Storage Ring Test Accelerator using TE-wave transmission

    Directory of Open Access Journals (Sweden)

    S. De Santis

    2010-07-01

    Full Text Available A relatively new technique for measuring the electron cloud density in storage rings has been developed and successfully demonstrated [S. De Santis, J. M. Byrd, F. Caspers, A. Krasnykh, T. Kroyer, M. T. F. Pivi, and K. G. Sonnad, Phys. Rev. Lett. 100, 094801 (2008.PRLTAO0031-900710.1103/PhysRevLett.100.094801]. We present the experimental results of a systematic application of this technique at the Cornell Electron Storage Ring Test Accelerator. The technique is based on the phase modulation of the TE mode transmitted in a synchrotron beam pipe caused by the periodic variation of the density of electron plasma. Because of the relatively simple hardware requirements, this method has become increasingly popular and has been since successfully implemented in several machines. While the principles of this technique are straightforward, quantitative derivation of the electron cloud density from the measurement requires consideration of several effects, which we address in detail.

  19. Advantages of a monochromated transmission electron microscope for solid state physics

    International Nuclear Information System (INIS)

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

    2006-01-01

    Full text: The characterization of nanostructured devices and functional materials at a nanometer scale is paramount for the understanding of their physical and chemical properties. Transmission electron microscopy (TEM) plays a central role, especially in terms of structural and chemical analysis on a nearly atomic scale. In particular, electron energy-loss spectrometry (EELS) can obtain information not only about the chemical composition of a thin sample, but also about chemical bonding and electronic structure (ionization edge fine structures) and optical properties (through valence loss EELS). Recent instrumental advances like monochromators for the electron gun in the TEM have made it possible to reduce the energy resolution to 0.15 eV at an acceleration voltage of 200 kV. Another strong point of the method lies in the combination with a fine electron probe (0.2 nm) which allows to record EELS spectra with high energy resolution and spatial resolution in the range of 1 nm. The improved energy resolution opens new possibilities for studying detailed electronic structure and bonding effects in solids such as transmission metal oxides. The experimental results will be compared with x-ray absorption spectroscopy and band structure calculations. A better energy-resolution is particularly important for measurements in the low loss region of the EELS spectrum which provides the information about the band gap and the dielectric function. We will highlight the potential of the method for studying metallic nanoparticles and semiconducting devices. Additionally, the influence of the intrinsic effects like core-hole and excited lifetime broadening and delocalization of the inelastically scattered electrons will be discussed. (author)

  20. Examination Of Defect In Gas Pipeline By Gamma Transmission Scanning And Computed Tomography Techniques

    International Nuclear Information System (INIS)

    Dang Nguyen The Duy; Bui Trong Duy; Nguyen Huu Quang; Dang Nguyen Tuan; Pham Van Dao

    2011-01-01

    The transmission gamma scanning and computed tomography (CT) are advanced non-destructive testing techniques which can provide visual information to end-user. In recent years, industrial gamma scanning and CT equipment have been continuously improved in physical configuration and image reconstruction software have been supplemented with advanced algorithms, that can satisfy end-users with high quality computed tomography images. The first generation CT system with configuration of one source - one detector which is designed and fabricated by the Centre for Applications of Nuclear Technique in Industry (CANTI) is a dedicated equipment for examination of corrosion, erosion or blockage in petroleum pipeline. The equipment have two options of measurement: gamma transmission scanning and computed tomography scanning. The associated image reconstruction software have three image reconstruction algorithms: analytical (FBP), algebraic (ART) and statistical (EM) along with some advanced image processing techniques. CANTI had utilized the equipment to examine some fraction of gas transportation pipeline of PetroVietnam Gas Company, detected and evaluated the extent of defects, quickly providing useful information for the inspection and maintenance tasks of the client. (author)

  1. 2D strain mapping using scanning transmission electron microscopy Moiré interferometry and geometrical phase analysis.

    Science.gov (United States)

    Pofelski, A; Woo, S Y; Le, B H; Liu, X; Zhao, S; Mi, Z; Löffler, S; Botton, G A

    2018-04-01

    A strain characterization technique based on Moiré interferometry in a scanning transmission electron microscope (STEM) and geometrical phase analysis (GPA) method is demonstrated. The deformation field is first captured in a single STEM Moiré hologram composed of multiple sets of periodic fringes (Moiré patterns) generated from the interference between the periodic scanning grating, fixing the positions of the electron probe on the sample, and the crystal structure. Applying basic principles from sampling theory, the Moiré patterns arrangement is then simulated using a STEM electron micrograph reference to convert the experimental STEM Moiré hologram into information related to the crystal lattice periodicities. The GPA method is finally applied to extract the 2D relative strain and rotation fields. The STEM Moiré interferometry enables the local information to be de-magnified to a large length scale, comparable to what can be achieved in dark-field electron holography. The STEM Moiré GPA method thus extends the conventional high-resolution STEM GPA capabilities by providing comparable quantitative 2D strain mapping with a larger field of view (up to a few microns). Copyright © 2017 Elsevier B.V. All rights reserved.

  2. In-situ Transmission Electron Microscopy and Spectroscopy Studies of Interfaces in Li-ion Batteries: Challenges and Opportunities

    International Nuclear Information System (INIS)

    Wang, Chong M.; Xu, Wu; Liu, Jun; Choi, Daiwon; Arey, Bruce W.; Saraf, Laxmikant V.; Zhang, Jiguang; Yang, Zhenguo; Thevuthasan, Suntharampillai; Baer, Donald R.; Salmon, Norman

    2010-01-01

    The critical challenge facing the lithium ion battery development is the basic understanding of the structural evolution during the cyclic operation of the battery and the consequence of the structural evolution on the properties of the battery. Although transmission electron microscopy (TEM) and spectroscopy have been evolved to a stage such that it can be routinely used to probe into both the structural and chemical composition of the materials with a spatial resolution of a single atomic column, a direct in-situ TEM observation of structural evolution of the materials in lithium ion battery during the dynamic operation of the battery has never been reported. This is related to three factors: high vacuum operation of a TEM; electron transparency requirement of the region to be observed, and the difficulties dealing with the liquid electrolyte of lithium ion battery. In this paper, we report the results of exploring the in-situ TEM techniques for observation of the interface in lithium ion battery during the operation of the battery. A miniature battery was fabricated using a nanowire and an ionic liquid electrolyte. The structure and chemical composition of the interface across the anode and the electrolyte was studied using TEM imaging, electron diffraction, and electron energy loss spectroscopy. In addition, we also explored the possibilities of carrying out in-situ TEM studies of lithium ion batteries with a solid state electrolyte.

  3. Study of planar defects associated to martensite transformation in copper alloys by transmission electron microscopy

    International Nuclear Information System (INIS)

    Condo, A.M.

    1997-01-01

    In this work the planar faults in non-compact planes (non-basal faults) in the 2H and 18R martensitic phases in Cu-Zn-Al alloys are analyzed. The study was carried out using transmission electron microscopy (TEM) combining the two-beam condition technique, high resolution transmission electron microscopy (HRTEM) and computer simulated images. The displacement vectors of the faults were determined. It was found that these vectors were different from those of the basal faults, even though the faults are connected. One single class of non-basal faults, named F 1 , was observed in the 2H phase, whereas two different classes were found in the 18R phase, named F o and F x . In the latter phase non-basal faults made up of different segments of F o and F x faults were observed (composed faults). The Burgers vectors of the partial dislocations at the edges of the non-basal faults were determined in both phases. Additionally, the Burgers vectors of the intermediate dislocations found between the different segments of the composed faults in the 18R phase were determined. It was verified that there exist two types of dislocations with Burgers vectors that differ in approximately 1/3 [100]. It was found that the presence of a particular dislocation type depends on the arrangement between the non-basal fault and the basal fault that originates the dislocation. The internal structure of the non-basal faults in the 18R phase was studied with HRTEM. It was observed that the shift of the crystal planes due to the presence of the faults occurs in a region of a finite extension of about 1.5 nm. It was also observed that in this region the crystal planes appear rotated and lose the characteristic corrugation they have in the 18R structure. As a consequence of this, new translation vectors appear in the defect; this fact could be reflected in new plastic deformation systems. The rotation of the crystal planes in the non-basal faulted area of the 18R phase was compared with the rotation

  4. A novel Alamouti transmission technique via a single RF source and a miniaturized antenna system

    DEFF Research Database (Denmark)

    Alrabadi, Osama; Papadias, Constantinos B.

    2010-01-01

    A novel space-time transmission technique that emulates Alamouti code with a single RF source is proposed in this paper. An orthogonal block of two BPSK signals is transmitted over a duration of two symbol periods by exciting one RF port of a two-element antenna system every symbol period while...... terminating the other port with its matching impedance. Besides the orthogonality of the signals, the array far-field is a linear mixture of two orthonormal basis functions onto which the BPSK signals are mapped, hence independent fading among the signals is almost always guaranteed....

  5. Examination for analysis of minerals by means of dual energy gamma-ray transmission techniques

    International Nuclear Information System (INIS)

    Umeda, Iwao; Muto, Toshio; Kitsutaka, Raita.

    1996-01-01

    For application of dual energy gamma-ray transmission techniques to practical mineral grade analysis, some problems including selection of gamma-ray energies, influence of sample thickness and main causes of errors in measurement have been examined. The relationships between the R-values (the ratio of mass attenuation coefficients for low and high energy gamma-rays) and the effective atomic numbers for various samples (e.g., iron ore, coal and coke, limestone, minerals and gem stones) were determined using different energy combinations of gamma-rays from 152 Eu. On the basis of the experimental results, the optimum conditions for analysis of minerals were discussed. (author)

  6. The potential use of transmission tomographic techniques for the quality checking of cemented waste drums

    International Nuclear Information System (INIS)

    Huddleston, J.; Hutchinson, I.G.

    1986-01-01

    In support of the programme for the quality checking of encapsulated intermediate level waste, the possibilities of using transmission tomographic techniques for the determination of the physical properties of the drum are being considered. A literature survey has been undertaken and the possibilities of extracting data from video recordings of real time radiographs are considered. This work was carried out with financial support from British Nuclear Fuels plc and the UK Department of the Environment. In the DoE context, the results will be used in the formulation of Government Policy, but at this stage they do not necessarily represent Government Policy. (author)

  7. In-situ transmission electron microscopy growth of nanoparticles under extreme conditions

    International Nuclear Information System (INIS)

    Luce, F. P.; Azevedo, G. de M.; Baptista, D. L.; Zawislak, F. C.; Oliviero, E.; Fichtner, P. F. P.

    2016-01-01

    The formation and time resolved behavior of individual Pb nanoparticles embedded in silica have been studied by in-situ transmission electron microscopy observations at high temperatures (400–1100 °C) and under 200 keV electron irradiation. It is shown that under such extreme conditions, nanoparticles can migrate at long distances presenting a Brownian-like behavior and eventually coalesce. The particle migration phenomenon is discussed considering the influence of the thermal energy and the electron irradiation effects on the atomic diffusion process which is shown to control particle migration. These results and comparison with ex-situ experiments tackle the stability and the microstructure evolution of nanoparticles systems under extreme conditions. It elucidates on the effects of energetic particle irradiation-annealing treatments either as a tool or as a detrimental issue that could hamper their long-term applications in radiation-harsh environments such as in space or nuclear sectors

  8. In-situ transmission electron microscopy growth of nanoparticles under extreme conditions

    Energy Technology Data Exchange (ETDEWEB)

    Luce, F. P.; Azevedo, G. de M.; Baptista, D. L.; Zawislak, F. C. [Instituto de Física, Universidade Federal do Rio Grande do Sul, Porto Alegre 91501-970 (Brazil); Oliviero, E. [Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), CNRS-IN2P3-Université Paris-Sud, 91405 Orsay-Campus (France); Fichtner, P. F. P. [Instituto de Física, Universidade Federal do Rio Grande do Sul, Porto Alegre 91501-970 (Brazil); Escola de Engenharia, Universidade Federal do Rio Grande do Sul, Porto Alegre 91501-970 (Brazil)

    2016-01-21

    The formation and time resolved behavior of individual Pb nanoparticles embedded in silica have been studied by in-situ transmission electron microscopy observations at high temperatures (400–1100 °C) and under 200 keV electron irradiation. It is shown that under such extreme conditions, nanoparticles can migrate at long distances presenting a Brownian-like behavior and eventually coalesce. The particle migration phenomenon is discussed considering the influence of the thermal energy and the electron irradiation effects on the atomic diffusion process which is shown to control particle migration. These results and comparison with ex-situ experiments tackle the stability and the microstructure evolution of nanoparticles systems under extreme conditions. It elucidates on the effects of energetic particle irradiation-annealing treatments either as a tool or as a detrimental issue that could hamper their long-term applications in radiation-harsh environments such as in space or nuclear sectors.

  9. TECHNIQUES FOR THE STUDY OF THE ELECTRONIC PROPERTIES.

    Energy Technology Data Exchange (ETDEWEB)

    FERNANDEZ-GARCIA, M.; RODRIGUEZ, J.A.

    2006-06-30

    The electronic structure of a solid is affected by size and altered from the continuous electronic levels forming a band, characteristic of bulk or microsized solids, to discrete-like or quantized levels. This is drastically observed when the particle size goes down to the nano-meter range and is the origin of the so-called ''quantum confinement'' terminology referring to this phenomenon. From a solid state point of view, electronic states of confined materials can be considered as being a superposition of bulk-like states with a concomitant increase of the oscillator strength. The valence/conduction band-width and position observables of a solid oxide are functions of the crystal potential and this, in turn, is perturbed by effect of the size in two ways; a short-range effect induced by the presence of ions with a different coordination number and bond distance, and a large-range one, induced by changes in the Madelung potential of the oxide. Theoretical analyses for oxides show a redistribution of charge when going from large periodic structures to small clusters which is roughly considered small for ionic solids and significantly important for covalent ones. Chapter 1 of this book describes the most recent theoretical frameworks employed to deal with these physical phenomena while here we will describe their influence in physico-chemical observables obtained by spectroscopical techniques.

  10. Investigating the use of in situ liquid cell scanning transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nguy, Amanda [Iowa State Univ., Ames, IA (United States)

    2016-02-19

    Engineering nanoparticles with desired shape-dependent properties is the key to many applications in nanotechnology. Although many synthetic procedures exist to produce anisotropic gold nanoparticles, the dynamics of growth are typically unknown or hypothetical. In the case of seed-mediated growth in the presence of DNA into anisotropic nanoparticles, it is not known exactly how DNA directs growth into specific morphologies. A series of preliminary experiments were carried out to contribute to the investigation of the possible mechanism of DNA-mediated growth of gold nanoprisms into gold nanostars using liquid cell scanning transmission electron microscopy (STEM). Imaging in the liquid phase was achieved through the use of a liquid cell platform and liquid cell holder that allow the sample to be contained within a “chip sandwich” between two electron transparent windows. Ex situ growth experiments were performed using Au-T30 NPrisms (30-base thymine oligonucleotide-coated gold nanoprisms) that are expected to grow into gold nanostars. Growth to form these nanostars were imaged using TEM (transmission electron microscopy) and liquid cell STEM (scanning transmission electron microscopy). An attempt to perform in situ growth experiments with the same Au-T30 nanoprisms revealed challenges in obtaining desired morphology results due to the environmental differences within the liquid cell compared to the ex situ environment. Different parameters in the experimental method were explored including fluid line set up, simultaneous and alternating reagent addition, and the effect of different liquid cell volumes to ensure adequate flow of reagents into the liquid cell. Lastly, the binding affinities were compared for T30 and A30 DNA incubated with gold nanoparticles using zeta potential measurements, absorption spectroscopy, and isothermal titration calorimetry (ITC). It was previously reported thymine bases have a lower binding affinity to gold surfaces than adenine

  11. Study by transmission electron microscopy of ion and electron irradiation defects in zirconium and four alloys

    International Nuclear Information System (INIS)

    Hellio, C.

    1988-01-01

    In order to understand better zirconium growth under irradiation and to estimate the influence of alloying elements, we have performed crystallographic and kinetic analysis of the dislocation loops induced during 500 keV Zr + ion or 1 MeV electron irradiation in pure Zr and four of its alloys: Zr/1760 wt ppm 0. Zr/1 % Nb/430 ppm 0. Zr/1 % Nb/1800 ppm 0 and Zircaloy- 4 . The irradiations were realized between 400 and 700 0 C. The Burgers vectors of the observed loops are a/3 ; the loops lie preferentially on (1010) planes and are aligned along directions parallel to the (0001) plane. The loops induced by 1 MeV electron irradiation and of size larger than 10 nm are of interstitial type. The kinetic analysis shows that oxygen strongly decreases the loop groth speed, the apparent vacancy migration energy increasing from 0.72 eV for pure Zr to 1.76 eV for Zr/1750 ppm 0. The alloying elements (Sn, Nb, 0) increase the loop density. Observation of the microstructural behaviour shows that loops shrink and aggregate during annealing treatments after ion irradiation. This annealing is easier in pure zirconium than in its alloys [fr

  12. A technique for pediatric total skin electron irradiation

    International Nuclear Information System (INIS)

    Bao, Qinan; Hrycushko, Brian A; Dugas, Joseph P; Hager, Frederick H; Solberg, Timothy D

    2012-01-01

    Total skin electron irradiation (TSEI) is a special radiotherapy technique which has generally been used for treating adult patients with mycosis fungoides. Recently, two infants presented with leukemia cutis isolated to the skin requiring TSEI. This work discusses the commissioning and quality assurance (QA) methods for implementing a modified Stanford technique using a rotating harness system to position sedated pediatric patients treated with electrons to the total skin. Commissioning of pediatric TSEI consisted of absolute calibration, measurement of dosimetric parameters, and subsequent verification in a pediatric patient sized cylindrical phantom using radiographic film and optically stimulated luminance (OSL) dosimeters. The depth of dose penetration under TSEI treatment condition was evaluated using radiographic film sandwiched in the phantom and demonstrated a 2 cm penetration depth with the maximum dose located at the phantom surface. Dosimetry measurements on the cylindrical phantom and in-vivo measurements from the patients suggested that, the factor relating the skin and calibration point doses (i.e., the B-factor) was larger for the pediatric TSEI treatments as compared to adult TSEI treatments. Custom made equipment, including a rotating plate and harness, was fabricated and added to a standard total body irradiation stand and tested to facilitate patient setup under sedated condition. A pediatric TSEI QA program, consisting of daily output, energy, flatness, and symmetry measurements as well as in-vivo dosimetry verification for the first cycle was developed. With a long interval between pediatric TSEI cases, absolute dosimetry was also repeated as part of the QA program. In-vivo dosimetry for the first two infants showed that a dose of ± 10% of the prescription dose can be achieved over the entire patient body. Though pediatric leukemia cutis and the subsequent need for TSEI are rare, the ability to commission the technique on a modified TBI stand

  13. Characterization of ELISA Antibody-Antigen Interaction using Footprinting-Mass Spectrometry and Negative Staining Transmission Electron Microscopy

    Science.gov (United States)

    Lin, Margaret; Krawitz, Denise; Callahan, Matthew D.; Deperalta, Galahad; Wecksler, Aaron T.

    2018-03-01

    We describe epitope mapping data using multiple covalent labeling footprinting-mass spectrometry (MS) techniques coupled with negative stain transmission electron microscopy (TEM) data to analyze the antibody-antigen interactions in a sandwich enzyme-linked immunosorbant assay (ELISA). Our hydroxyl radical footprinting-MS data using fast photochemical oxidation of proteins (FPOP) indicates suppression of labeling across the antigen upon binding either of the monoclonal antibodies (mAbs) utilized in the ELISA. Combining these data with Western blot analysis enabled the identification of the putative epitopes that appeared to span regions containing N-linked glycans. An additional structural mapping technique, carboxyl group footprinting-mass spectrometry using glycine ethyl ester (GEE) labeling, was used to confirm the epitopes. Deglycosylation of the antigen resulted in loss of potency in the ELISA, supporting the FPOP and GEE labeling data by indicating N-linked glycans are necessary for antigen binding. Finally, mapping of the epitopes onto the antigen crystal structure revealed an approximate 90° relative spatial orientation, optimal for a noncompetitive binding ELISA. TEM data shows both linear and diamond antibody-antigen complexes with a similar binding orientation as predicted from the two footprinting-MS techniques. This study is the first of its kind to utilize multiple bottom-up footprinting-MS techniques and TEM visualization to characterize the monoclonal antibody-antigen binding interactions of critical reagents used in a quality control (QC) lot-release ELISA. [Figure not available: see fulltext.

  14. Validities of three multislice algorithms for quantitative low-energy transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ming, W.Q.; Chen, J.H., E-mail: jhchen123@hnu.edu.cn

    2013-11-15

    Three different types of multislice algorithms, namely the conventional multislice (CMS) algorithm, the propagator-corrected multislice (PCMS) algorithm and the fully-corrected multislice (FCMS) algorithm, have been evaluated in comparison with respect to the accelerating voltages in transmission electron microscopy. Detailed numerical calculations have been performed to test their validities. The results show that the three algorithms are equivalent for accelerating voltage above 100 kV. However, below 100 kV, the CMS algorithm will introduce significant errors, not only for higher-order Laue zone (HOLZ) reflections but also for zero-order Laue zone (ZOLZ) reflections. The differences between the PCMS and FCMS algorithms are negligible and mainly appear in HOLZ reflections. Nonetheless, when the accelerating voltage is further lowered to 20 kV or below, the PCMS algorithm will also yield results deviating from the FCMS results. The present study demonstrates that the propagation of the electron wave from one slice to the next slice is actually cross-correlated with the crystal potential in a complex manner, such that when the accelerating voltage is lowered to 10 kV, the accuracy of the algorithms is dependent of the scattering power of the specimen. - Highlights: • Three multislice algorithms for low-energy transmission electron microscopy are evaluated. • The propagator-corrected algorithm is a good alternative for voltages down to 20 kV. • Below 20 kV, a fully-corrected algorithm has to be employed for quantitative simulations.

  15. 3D simulation of electron and ion transmission of GEM-based detectors

    Science.gov (United States)

    Bhattacharya, Purba; Mohanty, Bedangadas; Mukhopadhyay, Supratik; Majumdar, Nayana; da Luz, Hugo Natal

    2017-10-01

    Time Projection Chamber (TPC) has been chosen as the main tracking system in several high-flux and high repetition rate experiments. These include on-going experiments such as ALICE and future experiments such as PANDA at FAIR and ILC. Different R&D activities were carried out on the adoption of Gas Electron Multiplier (GEM) as the gas amplification stage of the ALICE-TPC upgrade version. The requirement of low ion feedback has been established through these activities. Low ion feedback minimizes distortions due to space charge and maintains the necessary values of detector gain and energy resolution. In the present work, Garfield simulation framework has been used to study the related physical processes occurring within single, triple and quadruple GEM detectors. Ion backflow and electron transmission of quadruple GEMs, made up of foils with different hole pitch under different electromagnetic field configurations (the projected solutions for the ALICE TPC) have been studied. Finally a new triple GEM detector configuration with low ion backflow fraction and good electron transmission properties has been proposed as a simpler GEM-based alternative suitable for TPCs for future collider experiments.

  16. Individual Particle Analysis of Ambient PM 2.5 Using Advanced Electron Microscopy Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Gerald J. Keeler; Masako Morishita

    2006-12-31

    The overall goal of this project was to demonstrate a combination of advanced electron microscopy techniques that can be effectively used to identify and characterize individual particles and their sources. Specific techniques to be used include high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), STEM energy dispersive X-ray spectrometry (EDX), and energy-filtered TEM (EFTEM). A series of ambient PM{sub 2.5} samples were collected in communities in southwestern Detroit, MI (close to multiple combustion sources) and Steubenville, OH (close to several coal fired utility boilers). High-resolution TEM (HRTEM) -imaging showed a series of nano-metal particles including transition metals and elemental composition of individual particles in detail. Submicron and nano-particles with Al, Fe, Ti, Ca, U, V, Cr, Si, Ba, Mn, Ni, K and S were observed and characterized from the samples. Among the identified nano-particles, combinations of Al, Fe, Si, Ca and Ti nano-particles embedded in carbonaceous particles were observed most frequently. These particles showed very similar characteristics of ultrafine coal fly ash particles that were previously reported. By utilizing HAADF-STEM, STEM-EDX, and EF-TEM, this investigation was able to gain information on the size, morphology, structure, and elemental composition of individual nano-particles collected in Detroit and Steubenville. The results showed that the contributions of local combustion sources - including coal fired utilities - to ultrafine particle levels were significant. Although this combination of advanced electron microscopy techniques by itself can not identify source categories, these techniques can be utilized as complementary analytical tools that are capable of providing detailed information on individual particles.

  17. In Situ Transmission Electron Microscopy Study of Electron Beam-Induced Transformations in Colloidal Cesium Lead Halide Perovskite Nanocrystals

    Science.gov (United States)

    2017-01-01

    An increasing number of studies have recently reported the rapid degradation of hybrid and all-inorganic lead halide perovskite nanocrystals under electron beam irradiation in the transmission electron microscope, with the formation of nanometer size, high contrast particles. The nature of these nanoparticles and the involved transformations in the perovskite nanocrystals are still a matter of debate. Herein, we have studied the effects of high energy (80/200 keV) electron irradiation on colloidal cesium lead bromide (CsPbBr3) nanocrystals with different shapes and sizes, especially 3 nm thick nanosheets, a morphology that facilitated the analysis of the various ongoing processes. Our results show that the CsPbBr3 nanocrystals undergo a radiolysis process, with electron stimulated desorption of a fraction of bromine atoms and the reduction of a fraction of Pb2+ ions to Pb0. Subsequently Pb0 atoms diffuse and aggregate, giving rise to the high contrast particles, as previously reported by various groups. The diffusion is facilitated by both high temperature and electron beam irradiation. The early stage Pb nanoparticles are epitaxially bound to the parent CsPbBr3 lattice, and evolve into nonepitaxially bound Pb crystals upon further irradiation, leading to local amorphization and consequent dismantling of the CsPbBr3 lattice. The comparison among CsPbBr3 nanocrystals with various shapes and sizes evidences that the damage is particularly pronounced at the corners and edges of the surface, due to a lower diffusion barrier for Pb0 on the surface than inside the crystal and the presence of a larger fraction of under-coordinated atoms. PMID:28122188

  18. Laser-Induced Skyrmion Writing and Erasing in an Ultrafast Cryo-Lorentz Transmission Electron Microscope

    Science.gov (United States)

    Berruto, G.; Madan, I.; Murooka, Y.; Vanacore, G. M.; Pomarico, E.; Rajeswari, J.; Lamb, R.; Huang, P.; Kruchkov, A. J.; Togawa, Y.; LaGrange, T.; McGrouther, D.; Rønnow, H. M.; Carbone, F.

    2018-03-01

    We demonstrate that light-induced heat pulses of different duration and energy can write Skyrmions in a broad range of temperatures and magnetic field in FeGe. Using a combination of camera-rate and pump-probe cryo-Lorentz transmission electron microscopy, we directly resolve the spatiotemporal evolution of the magnetization ensuing optical excitation. The Skyrmion lattice was found to maintain its structural properties during the laser-induced demagnetization, and its recovery to the initial state happened in the sub-μ s to μ s range, depending on the cooling rate of the system.

  19. In-situ reduction of promoted cobalt oxide supported on alumina by environmental transmission electron microscopy

    DEFF Research Database (Denmark)

    Dehghan, Roya; Hansen, Thomas Willum; Wagner, Jakob Birkedal

    2011-01-01

    Reduction of 12wt.%Co/0.5wt.%Re/α-Al2O3 Fischer–Tropsch catalyst has been studied in-situ in an environmental transmission electron microscope. Reduction of Co3O4 to metallic cobalt was observed dynamically at 360 °C under 3.4 mbar H2. Structural and morphological changes were observed by high...... the reactivity of the nanoparticles and the importance of controlling the gas composition and specimen temperature during this type of experiment. Similar behaviour was observed for a non-promoted catalyst. Imaging and analysis of the promoted sample before and after reduction indicated a uniform distribution...

  20. In situ transmission electron microscope observation of the formation of fuzzy structures on tungsten

    International Nuclear Information System (INIS)

    Miyamoto, M; Watanabe, T; Nagashima, H; Nishijima, D; Doerner, R P; Krasheninnikov, S I; Sagara, A; Yoshida, N

    2014-01-01

    To investigate the formation processes of tungsten nano-structures, so called fuzz, in situ transmission electron microscope observations during helium ion irradiation and high temperature annealing have been performed. The irradiation with 3 keV He + from room temperature to 1273 K is found to cause high-density helium bubbles in tungsten with no significant change in the surface structure. At higher temperatures, surface morphology changes were observed even without helium irradiation due probably to surface diffusion of tungsten atoms driven by surface tension. It is clearly shown that this morphology change is enhanced with helium irradiation, i.e. the formation of helium bubbles. (paper)

  1. Dynamics of annular bright field imaging in scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Findlay, S.D.; Shibata, N.; Sawada, H.; Okunishi, E.; Kondo, Y.; Ikuhara, Y.

    2010-01-01

    We explore the dynamics of image formation in the so-called annular bright field mode in scanning transmission electron microscopy, whereby an annular detector is used with detector collection range lying within the cone of illumination, i.e. the bright field region. We show that this imaging mode allows us to reliably image both light and heavy columns over a range of thickness and defocus values, and we explain the contrast mechanisms involved. The role of probe and detector aperture sizes is considered, as is the sensitivity of the method to intercolumn spacing and local disorder.

  2. 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)

  3. Transmission electron microscopy study of vertical quantum dots molecules grown by droplet epitaxy

    International Nuclear Information System (INIS)

    Hernandez-Maldonado, D.; Herrera, M.; Sales, D.L.; Alonso-Gonzalez, P.; Gonzalez, Y.; Gonzalez, L.; Pizarro, J.; Galindo, P.L.; Molina, S.I.

    2010-01-01

    The compositional distribution of InAs quantum dots grown by molecular beam epitaxy on GaAs capped InAs quantum dots has been studied in this work. Upper quantum dots are nucleated preferentially on top of the quantum dots underneath, which have been nucleated by droplet epitaxy. The growth process of these nanostructures, which are usually called as quantum dots molecules, has been explained. In order to understand this growth process, the analysis of the strain has been carried out from a 3D model of the nanostructure built from transmission electron microscopy images sensitive to the composition.

  4. In situ break-junction sample holder for transmission electron microscopy

    Science.gov (United States)

    Eswara Moorthy, Santhana K.; Le Goff, Gerald; Viret, Michel; Kociak, Mathieu

    2013-12-01

    In this article, we report on the design and construction of an in situ break-junction sample holder for transmission electron microscopy. The holder is based on the differential-screw mechanism. The technical details and a comprehensive consideration to all relevant critical issues surrounding the instrumentation procedure are presented. An application of the newly developed instrument is demonstrated using the example of a micro-scale gold wire. We also provide a detailed discussion on the challenges involved and the pitfalls to avoid in developing similar in situ holders.

  5. Cryogenic transmission electron microscopy (cryo-TEM) for studying the morphology of colloidal drug delivery systems

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Horst, Jennifer C; Bunjes, Heike

    2011-01-01

    Cryogenic transmission electron microscopy (cryo-TEM) has evolved into an indispensable tool for the characterization of colloidal drug delivery systems. It can be applied to study the size, shape and internal structure of nanoparticulate carrier systems as well as the overall colloidal composition...... of the corresponding dispersions. This review gives a short overview over the instrumentation used in cryo-TEM experiments and over the sample preparation procedure. Selected examples of cryo-TEM studies on colloidal drug carrier systems, including liposomes, colloidal lipid emulsions, solid lipid nanoparticles...

  6. Transmission electron microscopy study of vertical quantum dots molecules grown by droplet epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Maldonado, D., E-mail: david.hernandez@uca.es [Departamento de Ciencia de los Materiales e I.M. y Q.I., Facultad de Ciencias, Universidad de Cadiz, Campus Rio San Pedro, s/n, 11510 Puerto Real, Cadiz (Spain); Herrera, M.; Sales, D.L. [Departamento de Ciencia de los Materiales e I.M. y Q.I., Facultad de Ciencias, Universidad de Cadiz, Campus Rio San Pedro, s/n, 11510 Puerto Real, Cadiz (Spain); Alonso-Gonzalez, P.; Gonzalez, Y.; Gonzalez, L. [Instituto de Microelectronica de Madrid (CNM-CSIC), Isaac Newton 8 (PTM), 28760 Tres Cantos, Madrid (Spain); Pizarro, J.; Galindo, P.L. [Departamento de Lenguajes y Sistemas Informaticos, CASEM, Universidad de Cadiz, Campus Rio San Pedro, s/n, 11510 Puerto Real, Cadiz (Spain); Molina, S.I. [Departamento de Ciencia de los Materiales e I.M. y Q.I., Facultad de Ciencias, Universidad de Cadiz, Campus Rio San Pedro, s/n, 11510 Puerto Real, Cadiz (Spain)

    2010-07-01

    The compositional distribution of InAs quantum dots grown by molecular beam epitaxy on GaAs capped InAs quantum dots has been studied in this work. Upper quantum dots are nucleated preferentially on top of the quantum dots underneath, which have been nucleated by droplet epitaxy. The growth process of these nanostructures, which are usually called as quantum dots molecules, has been explained. In order to understand this growth process, the analysis of the strain has been carried out from a 3D model of the nanostructure built from transmission electron microscopy images sensitive to the composition.

  7. Nanohematite from Ferruginous Quartzites of Kursk Magnetic Anomaly According to Transmission Electron Microscopy Data

    Science.gov (United States)

    Zhukhlistov, A. P.; Novikov, V. M.

    2018-01-01

    Transmission electron microscopy study of ferruginous quartzite (jaspilites) from the Lebedinsky field of Kursk magnetic anomaly has revealed for the first time hematite nanoformations (about 10 nm in size), sp. gr. R3̅, which coexist with hematite, sp. gr. R3̅ c, in the same crystallographic orientation or manifest themselves as individual nanoinclusions in the substrate of poorly crystallized magnetite. On the assumption that, in correspondence with the energy-dispersive X-ray analysis data, octahedral sites in the hematite structure can be occupied by only Fe cations, several structural models are proposed explain the hematite symmetry lowering to R3̅.

  8. Combining nanocalorimetry and dynamic transmission electron microscopy for in situ characterization of materials processes under rapid heating and cooling

    Energy Technology Data Exchange (ETDEWEB)

    Grapes, Michael D., E-mail: mgrapes1@jhu.edu [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); LaGrange, Thomas; Reed, Bryan W.; Campbell, Geoffrey H. [Condensed Matter and Materials Division, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Friedman, Lawrence H.; LaVan, David A., E-mail: david.lavan@nist.gov [Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Weihs, Timothy P., E-mail: weihs@jhu.edu [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

    2014-08-15

    Nanocalorimetry is a chip-based thermal analysis technique capable of analyzing endothermic and exothermic reactions at very high heating and cooling rates. Here, we couple a nanocalorimeter with an extremely fast in situ microstructural characterization tool to identify the physical origin of rapid enthalpic signals. More specifically, we describe the development of a system to enable in situ nanocalorimetry experiments in the dynamic transmission electron microscope (DTEM), a time-resolved TEM capable of generating images and electron diffraction patterns with exposure times of 30 ns–500 ns. The full experimental system consists of a modified nanocalorimeter sensor, a custom-built in situ nanocalorimetry holder, a data acquisition system, and the DTEM itself, and is capable of thermodynamic and microstructural characterization of reactions over a range of heating rates (10{sup 2} K/s–10{sup 5} K/s) accessible by conventional (DC) nanocalorimetry. To establish its ability to capture synchronized calorimetric and microstructural data during rapid transformations, this work describes measurements on the melting of an aluminum thin film. We were able to identify the phase transformation in both the nanocalorimetry traces and in electron diffraction patterns taken by the DTEM. Potential applications for the newly developed system are described and future system improvements are discussed.

  9. Combining structural and chemical information at the nanometer scale by correlative transmission electron microscopy and atom probe tomography.

    Science.gov (United States)

    Herbig, M; Choi, P; Raabe, D

    2015-06-01

    In many cases, the three-dimensional reconstructions from atom probe tomography (APT) are not sufficiently accurate to resolve crystallographic features such as lattice planes, shear bands, stacking faults, dislocations or grain boundaries. Hence, correlative crystallographic characterization is required in addition to APT at the exact same location of the specimen. Also, for the site-specific preparation of APT tips containing regions of interest (e.g. grain boundaries) correlative electron microscopy is often inevitable. Here we present a versatile experimental setup that enables performing correlative focused ion beam milling, transmission electron microscopy (TEM), and APT under optimized characterization conditions. The setup was designed for high throughput, robustness and practicability. We demonstrate that atom probe tips can be characterized by TEM in the same way as a standard TEM sample. In particular, the use of scanning nanobeam diffraction provides valuable complementary crystallographic information when being performed on atom probe tips. This technique enables the measurement of orientation and phase maps as known from electron backscattering diffraction with a spatial resolution down to one nanometer. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Determination of molecular parameters by electron collisions and laser techniques

    International Nuclear Information System (INIS)

    Colon, C.

    1989-01-01

    In this work a general procedure to study diatomic molecules in intermediate coupling scheme has been developed. This study allows to obtain expressions to calculate molecular line strengths and rotational transition intensities. These results are used in a numerical program to synthetize vibrational and rotational band spectra of any diatomic molecule. With this technique the experimental spectra of the first negative system of N 2 + and the fist positive system of N 2 are reproduced theoretically and it is possible to deduce its electronic transition moments values by comparison. Also the method has been applied to compare the synthetized bands with the experimental spectra of the B O u + -- x 1 Σ g + system of Au 2 and the A 2 Σ--- x 2 π system of OH. From these comparison band intensities and electronic moments can be deduced. The branching ratio method to measure the relative spectral response in the 1100-1560 A o =wavelength range of a vacuum uv monochromator has been used. Relative intensity of rotational lines with origine in a common upper vibrational-rotational level of Warner and Lyman systems of H 2 , have been measured. Also in this work, the deexcitation of the B 3 π + (0 + u ), v'=14 level of I 2 after pulsed laser excitation has been studied. The quenching cross sections by collisions with I 2 , H 2 , CO 2 and CH 4 have been determin-ed. (Author)

  11. A Document Imaging Technique for Implementing Electronic Loan Approval Process

    Directory of Open Access Journals (Sweden)

    J. Manikandan

    2015-04-01

    Full Text Available The image processing is one of the leading technologies of computer applications. Image processing is a type of signal processing, the input for image processor is an image or video frame and the output will be an image or subset of image [1]. Computer graphics and computer vision process uses an image processing techniques. Image processing systems are used in various environments like medical fields, computer-aided design (CAD, research fields, crime investigation fields and military fields. In this paper, we proposed a document image processing technique, for establishing electronic loan approval process (E-LAP [2]. Loan approval process has been tedious process, the E-LAP system attempts to reduce the complexity of loan approval process. Customers have to login to fill the loan application form online with all details and submit the form. The loan department then processes the submitted form and then sends an acknowledgement mail via the E-LAP to the requested customer with the details about list of documents required for the loan approval process [3]. The approaching customer can upload the scanned copies of all required documents. All this interaction between customer and bank take place using an E-LAP system.

  12. Dendritic gold nanowire growth observed in liquid with transmission electron microscopy.

    Science.gov (United States)

    Kraus, Tobias; de Jonge, Niels

    2013-07-02

    The growth of nanoscale gold dendrites was studied in situ in a thin liquid film with transmission electron microscopy (TEM) using a liquid cell with silicon nitride (SiN) windows. Gold nanoparticle seeds were covered by a thin liquid layer containing precursor solution. Dendrite nucleation was induced by the electron beam leading to an initial burst of growth. The growth then settled at tip velocities between 0.1 and 2.0 nm/s for different dendrites. Tip velocities fluctuated as different dendrite geometries grew from the tips. Those dendrites showing granularities in their structure experienced the largest growth speed. Comparison of the observed velocities with diffusion-limited growth rates suggests that dendrite growth in thin films at this scale is limited by diffusion. The described method may find application in research on the mechanisms behind dendrite growth and also to study other types of anisotropic growth of nanomaterials driven by crystal and twin geometries.

  13. Balamuthia mandrillaris: Further morphological observations of trophozoites by light, scanning and transmission electron microscopy.

    Science.gov (United States)

    González-Robles, Arturo; Lares-Villa, Fernando; Lares-Jiménez, Luis Fernando; Omaña-Molina, Maritza; Salazar-Villatoro, Lizbeth; Martínez-Palomo, Adolfo

    2015-10-01

    Additional morphological features of Balamuthia mandrillaris observed by light and electron microscopy are reported. Trophozoites were extremely pleomorphic: their cell shapes ranged from rounded to elongated and sometimes they appeared exceptionally stretched out and branched. By transmission electron microscopy it was possible to observe two different cytoplasmic areas, the ectoplasm and the endoplasm and often sections of rough endoplasmic reticulum were found in the transition zone. The cytoplasm was very fibrogranular and most of the organelles typically found in eukaryotic cells were observed. A particular finding was the presence of numerous mitochondria with a different structure from those of other free-living amoebae. The observations reported here may reinforce the morphological knowledge of this amoeba and provide a background for further analyses. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Image transfer with spatial coherence for aberration corrected transmission electron microscopes.

    Science.gov (United States)

    Hosokawa, Fumio; Sawada, Hidetaka; Shinkawa, Takao; Sannomiya, Takumi

    2016-08-01

    The formula of spatial coherence involving an aberration up to six-fold astigmatism is derived for aberration-corrected transmission electron microscopy. Transfer functions for linear imaging are calculated using the newly derived formula with several residual aberrations. Depending on the symmetry and origin of an aberration, the calculated transfer function shows characteristic symmetries. The aberrations that originate from the field's components, having uniformity along the z direction, namely, the n-fold astigmatism, show rotational symmetric damping of the coherence. The aberrations that originate from the field's derivatives with respect to z, such as coma, star, and three lobe, show non-rotational symmetric damping. It is confirmed that the odd-symmetric wave aberrations have influences on the attenuation of an image via spatial coherence. Examples of image simulations of haemoglobin and Si [211] are shown by using the spatial coherence for an aberration-corrected electron microscope. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Optical depth sectioning in the aberration-corrected scanning transmission and scanning confocal electron microscope

    International Nuclear Information System (INIS)

    Behan, G; Nellist, P D

    2008-01-01

    The use of spherical aberration correctors in the scanning transmission electron microscope (STEM) has the effect of reducing the depth of field of the microscope, making three-dimensional imaging of a specimen possible by optical sectioning. Depth resolution can be improved further by placing aberration correctors and lenses pre and post specimen to achieve an imaging mode known as scanning confocal electron microscopy (SCEM). We present the calculated incoherent point spread functions (PSF) and optical transfer functions (OTF) of a STEM and SCEM. The OTF for a STEM is shown to have a missing cone region which results in severe blurring along the optic axis, which can be especially severe for extended objects. We also present strategies for reconstruction of experimental data, such as three-dimensional deconvolution of the point spread function.

  16. Third generation hybrid drive. Transmission-based integration of power electronics; Dritte Generation Hybridantrieb. Getriebenahe Integration der Leistungselektronik

    Energy Technology Data Exchange (ETDEWEB)

    Schoen, Wolfgang [ZF Friedrichshafen AG, Friedrichshafen (DE). Hybridantriebe (F und E); Lutz, Steffen [BMW AG, Muenchen (Germany); Hensler, Alexander [Technische Univ. Chemnitz (Germany); Munding, Andreas [Liebherr Elektronik GmbH, Lindau (Germany); Thoben, Markus [Infineon Technologies AG, Warstein (Germany); Zeidler, Dietmar [Kemet Electronics GmbH, Landsberg am Lech (Germany)

    2011-06-15

    The power electronics components in today's hybrid vehicles are situated at different places in the vehicle - till now far away from harsh and hot surroundings. In order to develop an integrated solution near the transmission, ZF and BMW launched the research project 'Electric components for active power transmissions' (EfA). On the basis of an eight-speed full hybrid transmission and together with Infineon, Kemet, Liebherr, and the University of Technology of Chemnitz, they are developing a power electronics unit, which facilitates doubling the power density while increasing the operating temperature. The project EfA will be concluded in June 2011. (orig.)

  17. In situ environmental transmission electron microscope investigation of NiGa nanoparticle synthesis

    DEFF Research Database (Denmark)

    Damsgaard, Christian Danvad; Duchstein, Linus Daniel Leonhard; Elkjær, Christian Fink

    2011-01-01

    detailed Environmental Transmission Electron Microscope (ETEM) investigations of synthesis of NiGa nanoparticles on a thin film support. Samples were prepared by dissolving Ni(NO3)2 and Ga(NO3)3 in a Ni:Ga ratio of 5:3 in millipore water. The solution was subsequently dispersed on transmission electron...... have predicted a nickel gallium alloy to be active for this reaction [1]. NiGa catalysts prepared by incipient wetness impregnation on a high surface area silica support (Saint-Gobain NorPro), using a solution of nickel and gallium nitrates have shown very promising results [2]. This work presents...... microscope (TEM) sample grids. The sample grid was then mounted in a TEM heating holder and inserted in a FEI Titan ETEM with imaging Cs corrector as well as facilities for in situ gas reactions [3]. The ETEM was operated at 300 kV. The synthesis was performed in situ in a H2 flow of 2 Nml/min at a pressure...

  18. Functional differentiation of spider hemocytes by light and transmission electron microscopy, and MALDI-MS-imaging.

    Science.gov (United States)

    Kuhn-Nentwig, Lucia; Kopp, Lukas S; Nentwig, Wolfgang; Haenni, Beat; Streitberger, Kathrin; Schürch, Stefan; Schaller, Johann

    2014-03-01

    The most abundant cell types in the hemolymph of Cupiennius salei are plasmatocytes (70-80%) and granulocytes (20-30%). Both cells differ in shape, cytochemical and transmission electron microscopy staining of their cytoplasma and granules. According to MALDI-IMS (matrix-assisted laser desorption ionisation-mass spectrometry imaging), granulocytes exhibit ctenidin 1 (9510 Da) and ctenidin 3 (9568 Da), SIBD-1 (8675 Da), and unknown peptides with masses of 2207 and 6239 Da. Plasmatocytes exhibit mainly a mass of 6908 Da. Unknown peptides with masses of 1546 and 1960 Da were detected in plasmatocytes and granulocytes. Transmission electron microscopy confirms the presence of two compounds in one granule and cytochemical staining (light microscopy) tends to support this view. Two further hemocyte types (cyanocytes containing hemocyanin and prehemocytes as stem cells) are only rarely detected in the hemolymph. These four hemocyte types constitute the cellular part of the spider immune system and this is discussed in view of arachnid hemocyte evolution. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. [Corneal epithelial changes of soft contact lens wearers under a transmission electron microscope].

    Science.gov (United States)

    Gu, Hao; Tang, Li

    2015-03-01

    To investigate the difference in corneal epithelium between patients with and without soft contact lens (SCL) wearing, and to analyze corneal epithelial changes of the eyes with long-time SCL wearing. In this cross sectional study, the subjects were divided into two groups: 13 patients of daily SCL wearers and 11 control subjects who had never worn contact lenses. The flap of corneal epithelium was observed by transmission electron microscopy. The corneal epithelial microvillus density was compared between the two groups. Transmission electron micrographs of the control group showed a tight connection between cells, regularly aligned basal cells, and continuous basement membrane. Compared with the control group, SCL wearers showed incomplete basement membrane, swollen epithelial cells, swollen mitochondria, and widened intercellular interstices. The density of corneal epithelium microvilli [(0.071466 +/- 0.015889)/microm2 vs. (0.139851 +/- 0.024171)/micro2] was lower (t = 8.312, P < 0.05). Long-term SCL wearing can induce remarkable changes of corneal epithelial tissue, and the density of corneal epithelial microvilli decreases.

  20. Prospecting nanomaterials in aqueous environments by cloud-point extraction coupled with transmission electron microscopy.

    Science.gov (United States)

    Yang, Yu; Reed, Robert; Schoepf, Jared; Hristovski, Kiril; Herckes, Pierre; Westerhoff, Paul

    2017-04-15

    Increasing application of engineered nanomaterials (ENMs) in industry and consumer products inevitably lead to their release into and impact on aquatic environments. To characterize the NMs efficiently in surface water, a fast and simple method is needed to separate and concentrate nanomaterials from the aqueous matrix without altering their shape and size. Applying cloud-point extraction (CPE) using the surfactant Triton 114 to an array of NMs (titanium dioxide, gold, silver, and silicon dioxide) with different sizes or capping agents in nanopure water resulted in extraction efficiency of 83%-107%. Additional CPE experiments were conducted to extract NMs from surface, potable, and sewage waters, and NMs enriched in the surfactant phase were characterized using transmission electron microscopy coupled with energy dispersive x-ray spectroscopy. The most abundant nanoparticles identified in surface water were silica, titanium dioxide, and iron oxide with 4-99nm diameter. The extraction efficiencies of CPE for silicon, titanium, and iron elements from environmental water samples were 51%, 15%, and 99%, respectively. This study applied CPE with TEM to enrich and analyze popular nanoparticles such as SiO 2 and TiO 2 from natural waters, which has not been well addressed by previous researches. Overall, CPE coupled with transmission electron microscopy (TEM) can be an effective method to characterize NMs in aqueous water samples, and further optimization will increase the extraction efficiency of NMs in complicated surface water matrix. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. A dual energy gamma-ray transmission technique for gold alloy identification

    International Nuclear Information System (INIS)

    Sumi, Tetsuo; Shingu, Hiroyasu; Iwase, Hirotoshi

    1991-01-01

    An application of the dual energy gamma-ray transmission techniques to gold alloy identification is presented. The measurement by dual energy gamma-ray transmission is independent of thickness and density of a sample. Due to this advantage, golden accessories such as necklaces, earrings and rings can be assayed in spite of their various thicknesses and irregular sectional shapes. Choice of a gamma-ray energy pair suitable for the object is important. The authors chose 511 keV and 1275 keV gamma-rays from 22 Na. With this energy pair, R value (a ratio of mass attenuation coefficients for low and high energy gamma-rays) is predominantly related to the weight fraction of gold of the sample. Using a 370 kBq 22 Na small source and a 50 mm dia.x 50 mm thick NaI(Tl) scintillator for 1200 seconds, a resolution of 2% for the R value was obtained. This corresponds to approximately 5% of the weight fraction of gold. A better resolution can be obtained by increasing the source activity or measurement time. (author)

  2. 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.

  3. The Probe Profile and Lateral Resolution of Scanning Transmission Electron Microscopy of Thick Specimens

    Science.gov (United States)

    Demers, Hendrix; Ramachandra, Ranjan; Drouin, Dominique; de Jonge, Niels

    2012-01-01

    Lateral profiles of the electron probe of scanning transmission electron microscopy (STEM) were simulated at different vertical positions in a micrometers-thick carbon sample. The simulations were carried out using the Monte Carlo method in the CASINO software. A model was developed to fit the probe profiles. The model consisted of the sum of a Gaussian function describing the central peak of the profile, and two exponential decay functions describing the tail of the profile. Calculations were performed to investigate the fraction of unscattered electrons as function of the vertical position of the probe in the sample. Line scans were also simulated over gold nanoparticles at the bottom of a carbon film to calculate the achievable resolution as function of the sample thickness and the number of electrons. The resolution was shown to be noise limited for film thicknesses less than 1 μm. Probe broadening limited the resolution for thicker films. The validity of the simulation method was verified by comparing simulated data with experimental data. The simulation method can be used as quantitative method to predict STEM performance or to interpret STEM images of thick specimens. PMID:22564444

  4. In Situ Transmission Electron Microscopy Modulation of Transport in Graphene Nanoribbons.

    Science.gov (United States)

    Rodríguez-Manzo, Julio A; Qi, Zhengqing John; Crook, Alexander; Ahn, Jae-Hyuk; Johnson, A T Charlie; Drndić, Marija

    2016-04-26

    In situ transmission electron microscopy (TEM) electronic transport measurements in nanoscale systems have been previously confined to two-electrode configurations. Here, we use the focused electron beam of a TEM to fabricate a three-electrode geometry from a continuous 2D material where the third electrode operates as side gate in a field-effect transistor configuration. Specifically, we demonstrate TEM nanosculpting of freestanding graphene sheets into graphene nanoribbons (GNRs) with proximal graphene side gates, together with in situ TEM transport measurements of the resulting GNRs, whose conductance is modulated by the side-gate potential. The TEM electron beam displaces carbon atoms from the graphene sheet, and its position is controlled with nanometer precision, allowing the fabrication of GNRs of desired width immediately prior to each transport measurement. We also model the corresponding electric field profile in this three-terminal geometry. The implementation of an in situ TEM three-terminal platform shown here further extends the use of a TEM for device characterization. This approach can be easily generalized for the investigation of other nanoscale systems (2D materials, nanowires, and single molecules) requiring the correlation of transport and atomic structure.

  5. Quantitative atomic resolution mapping using high-angle annular dark field scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Van Aert, S.; Verbeeck, J.; Erni, R.; Bals, S.; Luysberg, M.; Dyck, D. Van; Tendeloo, G. Van

    2009-01-01

    A model-based method is proposed to relatively quantify the chemical composition of atomic columns using high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) images. The method is based on a quantification of the total intensity of the scattered electrons for the individual atomic columns using statistical parameter estimation theory. In order to apply this theory, a model is required describing the image contrast of the HAADF STEM images. Therefore, a simple, effective incoherent model has been assumed which takes the probe intensity profile into account. The scattered intensities can then be estimated by fitting this model to an experimental HAADF STEM image. These estimates are used as a performance measure to distinguish between different atomic column types and to identify the nature of unknown columns with good accuracy and precision using statistical hypothesis testing. The reliability of the method is supported by means of simulated HAADF STEM images as well as a combination of experimental images and electron energy-loss spectra. It is experimentally shown that statistically meaningful information on the composition of individual columns can be obtained even if the difference in averaged atomic number Z is only 3. Using this method, quantitative mapping at atomic resolution using HAADF STEM images only has become possible without the need of simultaneously recorded electron energy loss spectra.

  6. What environmental transmission electron microscopy measures and how this links to diffusivity: thermodynamics versus kinetics.

    Science.gov (United States)

    Walther, T

    2015-02-01

    Environmental or in situ electron microscopy means the observation of material in its native environment, which can be gaseous or liquid, as compared to more traditional post-mortem electron microscopy carried out under (ultra) high vacuum conditions. Experiments can be performed on bulk samples in scanning electron microscopes or on thinned samples in transmission (scanning) electron microscopes. In the latter, the movement, in real time and in situ, of nanoparticles, clusters or even single atoms on the surfaces of thinned material or within a liquid can be observed. It is argued here that due to the changes that a specimen typically undergoes during in situ observation, electron irradiation effects are difficult to evaluate and so thermodynamic parameters, such as activation energies for diffusion and segregation, which are governed by movements of only a minority of atoms in the specimen, cannot be reliably determined because of the potentially high energy transfer by the irradiating electron beam to some atoms in the sample. In order to measure diffusivities reliably, radiation effects and surface diffusion need to be excluded or kept minimal so as not to disturb the measurements, which can be checked by repeating experiments and comparing results as function of time and dose for the same position, at different positions or for different specimen thicknesses. Kinetic measurements of nucleation and growth phenomena, such as Ostwald ripening, are possibly influenced to a far lesser degree by irradiation effects, as a majority of atoms actively participate in these processes and if a small fraction of them will get extra energy from the irradiation process then their influence on the overall kinetics may be rather minor. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

  7. Biological Applications and Transmission Electron Microscopy Investigations of Mesoporous Silica Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Trewyn, Brian G. [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    The research presented and discussed within involves the development of novel biological applications of mesoporous silica nanoparticles (MSN) and an investigation of mesoporous material by transmission electron microscopy (TEM). Mesoporous silica nanoparticles organically functionalized shown to undergo endocytosis in cancer cells and drug release from the pores was controlled intracellularly and intercellularly. Transmission electron microscopy investigations demonstrated the variety of morphologies produced in this field of mesoporous silica nanomaterial synthesis. A series of room-temperature ionic liquid (RTIL) containing mesoporous silica nanoparticle (MSN) materials with various particle morphologies, including spheres, ellipsoids, rods, and tubes, were synthesized. By changing the RTIL template, the pore morphology was tuned from the MCM-41 type of hexagonal mesopores to rotational moire type of helical channels, and to wormhole-like porous structures. These materials were used as controlled release delivery nanodevices to deliver antibacterial ionic liquids against Escherichia coli K12. The involvement of a specific organosiloxane function group, covalently attached to the exterior of fluorescein doped mesoporous silica nanoparticles (FITC-MSN), on the degree and kinetics of endocytosis in cancer and plant cells was investigated. The kinetics of endocystosis of TEG coated FITC-MSN is significantly quicker than FITC-MSN as determined by flow cytometry experiments. The fluorescence confocal microscopy investigation showed the endocytosis of TEG coated-FITC MSN triethylene glycol grafted fluorescein doped MSN (TEG coated-FITC MSN) into both KeLa cells and Tobacco root protoplasts. Once the synthesis of a controlled-release delivery system based on MCM-41-type mesoporous silica nanorods capped by disulfide bonds with superparamagnetic iron oxide nanoparticles was completed. The material was characterized by general methods and the dosage and kinetics of the

  8. Novel production techniques of radioisotopes using electron accelerators

    Science.gov (United States)

    Lowe, Daniel Robert

    Non-traditional radioisotope production techniques using a compact, high power linear electron accelerator have been demonstrated and characterized for the production of 18F, 47Sc, 147 Pm, and 99mTc from a variety of target candidates. These isotopes are used extensively in the medical field as diagnostic and therapy radioisotopes, as well as the space industry as RTG's. Primary focus was placed on 99mTc as it constitutes approximately 80% of all diagnostic procedures in the medical community that use radioactive tracers. It was also the prime focus due to recent events at the Chalk River nuclear reactor, which caused global shortages of this isotope a few years ago. A Varian K15 LINAC was first used to show proof of principle in Las Vegas. Various samples were then taken to the Idaho Accelerator Center where they were activated using an electron LINAC capable of electron energies from 4 to 25 MeV at a beam power of approximately 1 kW. Production rates, cross sections, and viability studies were then performed and conducted to assess the effectiveness of the candidate target and the maximum production rate for each radioisotope. Production rates for 18F from lithium fluoride salts were shown to be ideal at 21MeV, namely 1.7 Ci per kg of LiF salt, per kW of beam current, per 10 hour irradiation time. As the typical hospital consumption of 18F is around 500 mCi per day, it is clear that a large amount of 18F can be made from a small (300 gram) sample of LiF salt. However, since there is no current separation process for 18F from 19F, the viability of this technique is limited until a separations technique is developed. Furthermore, the calculated cross section for this reaction is in good agreement with literature, which supports the techniques for the isotopes mentioned below. Production rates for 47Sc from vanadium oxide targets were shown to be a maximum at 25 MeV with a production rate of 2 mCi per day, assuming a 2 kW beam and a 10 kg target. While this

  9. Experimental Investigation of Space Radiation Processing in Lunar Soil Ilmenite: Combining Perspectives from Surface Science and Transmission Electron Microscopy

    Science.gov (United States)

    Christoffersen, R.; Keller, L. P.; Rahman, Z.; Baragiola, R.

    2010-01-01

    Energetic ions mostly from the solar wind play a major role in lunar space weathering because they contribute structural and chemical changes to the space-exposed surfaces of lunar regolith grains. In mature mare soils, ilmenite (FeTiO3) grains in the finest size fraction have been shown in transmission electron microscope (TEM) studies to exhibit key differences in their response to space radiation processing relative to silicates [1,2,3]. In ilmenite, solar ion radiation alters host grain outer margins to produce 10-100 nm thick layers that are microstructurally complex, but dominantly crystalline compared to the amorphous radiation-processed rims on silicates [1,2,3]. Spatially well-resolved analytical TEM measurements also show nm-scale compositional and chemical state changes in these layers [1,3]. These include shifts in Fe/Ti ratio from strong surface Fe-enrichment (Fe/Ti >> 1), to Fe depletion (Fe/Ti < 1) at 40-50 nm below the grain surface [1,3]. These compositional changes are not observed in the radiation-processed rims on silicates [4]. Several mechanism(s) to explain the overall relations in the ilmenite grain rims by radiation processing and/or additional space weathering processes were proposed by [1], and remain under current consideration [3]. A key issue has concerned the ability of ion radiation processing alone to produce some of the deeper- penetrating compositional changes. In order to provide some experimental constraints on these questions, we have performed a combined X-ray photoelectron spectroscopy (XPS) and field-emission scanning transmission electron (FE-STEM) study of experimentally ion-irradiated ilmenite. A key feature of this work is the combination of analytical techniques sensitive to changes in the irradiated samples at depth scales going from the immediate surface (approx.5 nm; XPS), to deeper in the grain interior (5-100 nm; FE-STEM).

  10. Further Evaluation of the Neutron Resonance Transmission Analysis (NRTA) Technique for Assaying Plutonium in Spent Fuel

    Energy Technology Data Exchange (ETDEWEB)

    J. W. Sterbentz; D. L. Chichester

    2011-09-01

    This is an end-of-year report (Fiscal Year (FY) 2011) for the second year of effort on a project funded by the National Nuclear Security Administration's Office of Nuclear Safeguards (NA-241). The goal of this project is to investigate the feasibility of using Neutron Resonance Transmission Analysis (NRTA) to assay plutonium in commercial light-water-reactor spent fuel. This project is part of a larger research effort within the Next-Generation Safeguards Initiative (NGSI) to evaluate methods for assaying plutonium in spent fuel, the Plutonium Assay Challenge. The second-year goals for this project included: (1) assessing the neutron source strength needed for the NRTA technique, (2) estimating count times, (3) assessing the effect of temperature on the transmitted signal, (4) estimating plutonium content in a spent fuel assembly, (5) providing a preliminary assessment of the neutron detectors, and (6) documenting this work in an end of the year report (this report). Research teams at Los Alamos National Laboratory (LANL), Lawrence Berkeley National Laboratory (LBNL), Pacific Northwest National Laboratory (PNNL), and at several universities are also working to investigate plutonium assay methods for spent-fuel safeguards. While the NRTA technique is well proven in the scientific literature for assaying individual spent fuel pins, it is a newcomer to the current NGSI efforts studying Pu assay method techniques having just started in March 2010; several analytical techniques have been under investigation within this program for two to three years or more. This report summarizes work performed over a nine month period from January-September 2011 and is to be considered a follow-on or add-on report to our previous published summary report from December 2010 (INL/EXT-10-20620).

  11. A hybrid lightwave transmission system based on light injection/optoelectronic feedback techniques and fiber-VLLC integration

    International Nuclear Information System (INIS)

    Tsai, Wen-Shing; Lu, Hai-Han; Li, Chung-Yi; Chen, Bo-Rui; Lin, Hung-Hsien; Lin, Dai-Hua

    2016-01-01

    A hybrid lightwave transmission system based on light injection/optoelectronic feedback techniques and fiber-visible laser light communication (VLLC) integration is proposed and experimentally demonstrated. To be the first one of its kind in employing light injection and optoelectronic feedback techniques in a fiber-VLLC integration lightwave transmission system, the light is successfully directly modulated with Community Access Television (CATV), 16-QAM, and 16-QAM-OFDM signals. Over a 40 km SMF and a 10 m free-space VLLC transport, good performances of carrier-to-noise ratio (CNR)/composite second-order (CSO)/composite triple-beat (CTB)/bit error rate (BER) are achieved for CATV/16-QAM/16-QAM-OFDM signals transmission. Such a hybrid lightwave transmission system would be very useful since it can provide broadband integrated services including CATV, Internet, and telecommunication services over both distribute fiber and in-building networks. (letter)

  12. Characterization of a pure C60 powder using transmission electron microscopy

    International Nuclear Information System (INIS)

    Loiseau, A.; Tendeloo, G. van; Bernier, P.

    1993-01-01

    Complementary to neutron and X ray diffraction, electron microscopy (TEM) is a very powerful technique for characterizing crystalline materials at microscopic and atomic scales. This technique has been rapidly used to study C60 and C70 solids and has allowed in particular to identify various lattice defects present in these materials and to determine different phase transitions through in situ experiments. In this paper, we present a preliminary investigation of pure C60 powder under different imaging conditions. The observed peculiarities are compared with previous studies. (orig.)

  13. In-situ Study of Dynamic Phenomena at Metal Nanosolder Interfaces Using Aberration Corrected Scanning Transmission Electron Microcopy.

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Ping

    2014-10-01

    Controlling metallic nanoparticle (NP) interactions plays a vital role in the development of new joining techniques (nanosolder) that bond at lower processing temperatures but remain viable at higher temperatures. The pr imary objective of this project is t o develop a fundamental understanding of the actual reaction processes, associated atomic mechanisms, and the resulting microstructure that occur during thermally - driven bond formation concerning metal - metal nano - scale (%3C50nm) interfaces. In this LDRD pr oject, we have studied metallic NPs interaction at the elevated temperatures by combining in - situ transmission electron microscopy (TEM ) using an aberration - corrected scanning transmission electron microscope (AC - STEM) and atomic - scale modeling such as m olecular dynamic (MD) simulations. Various metallic NPs such as Ag, Cu and Au are synthesized by chemical routines. Numerous in - situ e xperiments were carried out with focus of the research on study of Ag - Cu system. For the first time, using in - situ STEM he ating experiments , we directly observed t he formation of a 3 - dimensional (3 - D) epitaxial Cu - Ag core - shell nanoparticle during the thermal interaction of Cu and Ag NPs at elevated temperatures (150 - 300 o C). The reaction takes place at temperatures as low as 150 o C and was only observed when care was taken to circumvent the effects of electron beam irradiation during STEM imaging. Atomic - scale modeling verified that the Cu - Ag core - shell structure is energetically favored, and indicated that this phenomenon is a nano - scale effect related to the large surface - to - volume ratio of the NPs. The observation potentially can be used for developing new nanosolder technology that uses Ag shell as the "glue" that stic ks the particles of Cu together. The LDRD has led to several journal publications and numerous conference presentations, and a TA. In addition, we have developed new TEM characterization techniques and phase

  14. Enhanced rearrangement technique for secure data transmission: case study credit card process

    Science.gov (United States)

    Vyavahare, Tushar; Tekade, Darshana; Nayak, Saurabh; kumar, N. Suresh; Blessy Trencia Lincy, S. S.

    2017-11-01

    Encryption of data is very important in order to keep the data secure and make secure transactions and transmission of data. Such as online shopping. whenever we give our card details there is possibility of data being hacked or intruded. So to secure that we need to encrypt the data and decryption strategy should be known only to that particular bank. Therefore to achieve this objective RSA algorithm can be used. Where only intended sender and receiver can know about the encryption and decryption of data. To make the RSA technique more secure in this paper we propose the technique we call it Modified RSA. for which a transposition module is designed which uses Row Transposition method to encrypt the data. Before giving the card details to RSA the input will be given to this transposition module which will scrambles the data and rearranges it. Output of transposition will be then provided to the modified RSA which produces the cipher text to send over the network. Use of RSA and the transposition module will provide the dual security to whole system.

  15. Fabrication of high-transmission microporous membranes by proton beam writing-based molding technique

    Science.gov (United States)

    Wang, Liping; Meyer, Clemens; Guibert, Edouard; Homsy, Alexandra; Whitlow, Harry J.

    2017-08-01

    Porous membranes are widely used as filters in a broad range of micro and nanofluidic applications, e.g. organelle sorters, permeable cell growth substrates, and plasma filtration. Conventional silicon fabrication approaches are not suitable for microporous membranes due to the low mechanical stability of thin film substrates. Other techniques like ion track etching are limited to the production of randomly distributed and randomly orientated pores with non-uniform pore sizes. In this project, we developed a procedure for fabricating high-transmission microporous membranes by proton beam writing (PBW) with a combination of spin-casting and soft lithography. In this approach, focused 2 MeV protons were used to lithographically write patterns consisting of hexagonal arrays of high-density pillars of few μm size in a SU-8 layer coated on a silicon wafer. After development, the pillars were conformably coated with a thin film of poly-para-xylylene (Parylene)-C release agent and spin-coated with polydimethylsiloxane (PDMS). To facilitate demolding, a special technique based on the use of a laser-cut sealing tape ring was developed. This method facilitated the successful delamination of 20-μm thick PDMS membrane with high-density micropores from the mold without rupture or damage.

  16. Transmission electron microscopy for the evaluation and optimization of crystal growth.

    Science.gov (United States)

    Stevenson, Hilary P; Lin, Guowu; Barnes, Christopher O; Sutkeviciute, Ieva; Krzysiak, Troy; Weiss, Simon C; Reynolds, Shelley; Wu, Ying; Nagarajan, Veeranagu; Makhov, Alexander M; Lawrence, Robert; Lamm, Emily; Clark, Lisa; Gardella, Timothy J; Hogue, Brenda G; Ogata, Craig M; Ahn, Jinwoo; Gronenborn, Angela M; Conway, James F; Vilardaga, Jean Pierre; Cohen, Aina E; Calero, Guillermo

    2016-05-01

    The crystallization of protein samples remains the most significant challenge in structure determination by X-ray crystallography. Here, the effectiveness of transmission electron microscopy (TEM) analysis to aid in the crystallization of biological macromolecules is demonstrated. It was found that the presence of well ordered lattices with higher order Bragg spots, revealed by Fourier analysis of TEM images, is a good predictor of diffraction-quality crystals. Moreover, the use of TEM allowed (i) comparison of lattice quality among crystals from different conditions in crystallization screens; (ii) the detection of crystal pathologies that could contribute to poor X-ray diffraction, including crystal lattice defects, anisotropic diffraction and crystal contamination by heavy protein aggregates and nanocrystal nuclei; (iii) the qualitative estimation of crystal solvent content to explore the effect of lattice dehydration on diffraction and (iv) the selection of high-quality crystal fragments for microseeding experiments to generate reproducibly larger sized crystals. Applications to X-ray free-electron laser (XFEL) and micro-electron diffraction (microED) experiments are also discussed.

  17. Isotope substitution extends the lifetime of organic molecules in transmission electron microscopy.

    Science.gov (United States)

    Chamberlain, Thomas W; Biskupek, Johannes; Skowron, Stephen T; Bayliss, Peter A; Bichoutskaia, Elena; Kaiser, Ute; Khlobystov, Andrei N

    2015-02-04

    Structural characterisation of individual molecules by high-resolution transmission electron microscopy (HRTEM) is fundamentally limited by the element and electron energy-specific interactions of the material with the high energy electron beam. Here, the key mechanisms controlling the interactions between the e-beam and C-H bonds, present in all organic molecules, are examined, and the low atomic weight of hydrogen-resulting in its facile atomic displacement by the e-beam-is identified as the principal cause of the instability of individual organic molecules. It is demonstrated theoretically and proven experimentally that exchanging all hydrogen atoms within molecules with the deuterium isotope, and therefore doubling the atomic weight of the lightest atoms in the structure, leads to a more than two-fold increase in the stability of organic molecules in the e-beam. Substitution of H for D significantly reduces the amount of kinetic energy transferred from the e-beam to the atom (main factor contributing to stability) and also increases the barrier for bond dissociation, primarily due to the changes in the zero-point energy of the C-D vibration (minor factor). The extended lifetime of coronene-d12 , used as a model molecule, enables more precise analysis of the inter-molecular spacing and more accurate measurement of the molecular orientations. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Transmission electron microscopy for the evaluation and optimization of crystal growth

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, Hilary P.; Lin, Guowu; Barnes, Christopher O.; Sutkeviciute, Ieva; Krzysiak, Troy; Weiss, Simon C.; Reynolds, Shelley; Wu, Ying; Nagarajan, Veeranagu; Makhov, Alexander M.; Lawrence, Robert; Lamm, Emily; Clark, Lisa; Gardella, Timothy J.; Hogue, Brenda G.; Ogata, Craig M.; Ahn, Jinwoo; Gronenborn, Angela M.; Conway, James F.; Vilardaga, Jean-Pierre; Cohen, Aina E.; Calero, Guillermo

    2016-04-26

    The crystallization of protein samples remains the most significant challenge in structure determination by X-ray crystallography. Here, the effectiveness of transmission electron microscopy (TEM) analysis to aid in the crystallization of biological macromolecules is demonstrated. It was found that the presence of well ordered lattices with higher order Bragg spots, revealed by Fourier analysis of TEM images, is a good predictor of diffraction-quality crystals. Moreover, the use of TEM allowed (i) comparison of lattice quality among crystals from different conditions in crystallization screens; (ii) the detection of crystal pathologies that could contribute to poor X-ray diffraction, including crystal lattice defects, anisotropic diffraction and crystal contamination by heavy protein aggregates and nanocrystal nuclei; (iii) the qualitative estimation of crystal solvent content to explore the effect of lattice dehydration on diffraction and (iv) the selection of high-quality crystal fragments for microseeding experiments to generate reproducibly larger sized crystals. Applications to X-ray free-electron laser (XFEL) and micro-electron diffraction (microED) experiments are also discussed.

  19. Cryo-transmission electron microscopy of Ag nanoparticles grown on an ionic liquid substrate

    KAUST Repository

    Anjum, Dalaver H.

    2010-07-01

    We report a novel method of growing silver nanostructures by cathodic sputtering onto an ionic liquid (IL) and our visualization by transmission cryo-electron microscopy to avoid beam-induced motion of the nanoparticles. By freezing the IL suspension and controlling electron dose, we can assess properties of particle size, morphology, crystallinity, and aggregation in situ and at high detail. We observed round silver nanoparticles with a well-defined diameter of 7.0 ± 1.5 nm that are faceted with crystalline cubic structures and ∼80% of the particles have multiply twinned faults. We also applied cryo-electron tomography to investigate the structure of the nanoparticles and to directly visualize the IL wetting around them. In addition to particles, we observed nanorods that appear to have assembled from individual nanoparticles. Reexamination of the samples after 4-5 days from initial preparation showed significant changes in morphology, and potential mechanisms for this are discussed. © 2010 Materials Research Society.

  20. Image processing for cryogenic transmission electron microscopy of symmetry-mismatched complexes.

    Science.gov (United States)

    Huiskonen, Juha T

    2018-02-08

    Cryogenic transmission electron microscopy (cryo-TEM) is a high-resolution biological imaging method, whereby biological samples, such as purified proteins, macromolecular complexes, viral particles, organelles and cells, are embedded in vitreous ice preserving their native structures. Due to sensitivity of biological materials to the electron beam of the microscope, only relatively low electron doses can be applied during imaging. As a result, the signal arising from the structure of interest is overpowered by noise in the images. To increase the signal-to-noise ratio, different image processing-based strategies that aim at coherent averaging of signal have been devised. In such strategies, images are generally assumed to arise from multiple identical copies of the structure. Prior to averaging, the images must be grouped according to the view of the structure they represent and images representing the same view must be simultaneously aligned relatively to each other. For computational reconstruction of the three-dimensional structure, images must contain different views of the original structure. Structures with multiple symmetry-related substructures are advantageous in averaging approaches because each image provides multiple views of the substructures. However, the symmetry assumption may be valid for only parts of the structure, leading to incoherent averaging of the other parts. Several image processing approaches have been adapted to tackle symmetry-mismatched substructures with increasing success. Such structures are ubiquitous in nature and further computational method development is needed to understanding their biological functions. ©2018 The Author(s).

  1. Energy-filtered transmission electron microscopy of biological samples on highly transparent carbon nanomembranes

    International Nuclear Information System (INIS)

    Rhinow, Daniel; Bueenfeld, Matthias; Weber, Nils-Eike; Beyer, Andre; Goelzhaeuser, Armin; Kuehlbrandt, Werner; Hampp, Norbert; Turchanin, Andrey

    2011-01-01

    Ultrathin carbon nanomembranes (CNM) comprising crosslinked biphenyl precursors have been tested as support films for energy-filtered transmission electron microscopy (EFTEM) of biological specimens. Due to their high transparency CNM are ideal substrates for electron energy loss spectroscopy (EELS) and electron spectroscopic imaging (ESI) of stained and unstained biological samples. Virtually background-free elemental maps of tobacco mosaic virus (TMV) and ferritin have been obtained from samples supported by ∼1 nm thin CNM. Furthermore, we have tested conductive carbon nanomembranes (cCNM) comprising nanocrystalline graphene, obtained by thermal treatment of CNM, as supports for cryoEM of ice-embedded biological samples. We imaged ice-embedded TMV on cCNM and compared the results with images of ice-embedded TMV on conventional carbon film (CC), thus analyzing the gain in contrast for TMV on cCNM in a quantitative manner. In addition we have developed a method for the preparation of vitrified specimens, suspended over the holes of a conventional holey carbon film, while backed by ultrathin cCNM. -- Research highlights: → We examine ultrathin carbon nanomembranes (CNM) as supports for biological TEM. → CNM comprise crosslinked biphenyl precursors. → CNM supports enable background-free elemental mapping of heavy and light elements. → We perform cryoEM of ice-embedded biological samples on graphene-like conductive CNM.

  2. Analysis of the dopant distribution in Co-deposited organic thin films by scanning transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Paredes, Yolanda A. [Center of Nanotechnology and Nanoscience, Universidad de las Fuerzas Armadas ESPE, Sangolqui 171-5-31B (Ecuador); Campos, Andrea P.C.; Achete, Carlos A. [DIMAT—INMETRO, Xerém, Duque de Caxias, RJ 25250-020 (Brazil); Cremona, Marco [DIMAT—INMETRO, Xerém, Duque de Caxias, RJ 25250-020 (Brazil); Department of Physics, Pontifícia Universidade Católica do Rio de Janeiro, PUC-Rio, Rio de Janeiro, RJ 22453-970 (Brazil)

    2015-12-01

    Organic light-emitting diodes using phosphorescent dyes (PHOLEDs) have excellent performance, with internal quantum efficiencies approaching 100%. To maximize their performance, PHOLED devices use a conductive organic host material with a sufficiently dispersed phosphorescent guest to avoid concentration quenching. Fac-tris(2-phenylpyridine) iridium, [Ir(ppy){sub 3}] is one of the most widely used green phosphorescent organic compounds. In this work, we used scanning transmission electron microscopy (STEM) equipped with HAADF (high-angle annular dark-field) and EDS (energy dispersive X-ray spectroscopy) detectors to analyze the distribution of the [Ir(ppy){sub 3}] concentration in the host material. This analysis technique, employed for the first time in co-deposited organic thin films, can simultaneously obtain an image and its respective chemical information, allowing for definitive characterization of the distribution and morphology of [Ir(ppy){sub 3}]. The technique was also used to analyze the effect of the vibration of the substrate during thermal co-deposition of the [Ir(ppy){sub 3}] molecules into an organic matrix. - Highlights: • We present a methodology to analyze the dopant distribution in organic thin films. • The method combines HAADF-STEM imaging and EDS X-ray spectroscopy. • Ir(ppy){sub 3} dopant was co-deposited into Spiro2-CBP organic matrix. • The dopant was co-deposited with and without substrate vibration. • Images and chemical information of the dopant were simultaneously obtained.

  3. 3D estimation of synaptic vesicle distributions in serial section transmission electron microscopy

    DEFF Research Database (Denmark)

    Khanmohammadi, Mahdieh; Darkner, Sune; Nava, Nicoletta

    directly. It is hypothesized that in a rat model of behavioral stress the vesicles distribution varies. We propose methods for estimating the 3-dimensional distribution of synaptic vesicles from the active zone through serial section transmission electron microscope images (ssTEM) from Sprague-Dawley rat...... brains. We demonstrate that ssTEM images have an additive bias field, which is well modelled by a quadratic polynomial. ssTEM images make a 3D study on very high-resolution images possible. However, due to the physical cutting of a section from a 3D embedded tissue, the relations between sections...... difference in the results with p-values less than 10^(-10) in both cases. We conclude that the two proposed modeling significantly improves the measures on the estimated synaptic vesicle distribution in relation to the active zone....

  4. Fatigue tests and characterization of resulting microstructure by transmission electron microscope on zircaloy 4

    International Nuclear Information System (INIS)

    Di Toma, S.; Bertolino, G.; Tolley, A.

    2012-01-01

    This work reports the results of load controlled tension-tension fatigue tests on Zircaloy 4 (Zy-4). The resulting microstructure, particularly the kind and density of dislocations was characterized using a Transmission Electron Microscope (TEM). Specimens were cut from a rolled plate, with tensile axis parallel and perpendicular to the rolling direction. The results show a significant anisotropy of the mechanical properties due to the strong texture developed during rolling. Mainly type dislocations were observed, only in a longitudinal tensile axis specimen, dislocations were observed with a much lower density. The Schmid factors corresponding to the different glide systems were determined for specific grains in both tensile directions (author)

  5. Transmission electron microscopy of AlGaAs/GaAs quantum cascade laser structures.

    Science.gov (United States)

    Walther, T; Krysa, A B

    2017-12-01

    Quantum cascade lasers can be efficient infrared radiation sources and consist of several hundreds of very thin layers arranged in stacks that are repeated periodically. Both the thicknesses of the individual layers as well as the period lengths need to be monitored to high precision. Different transmission electron microscopy methods have been combined to analyse AlGaAs/GaAs quantum cascade laser structures in cross-section. We found a small parabolic variation of the growth rate during deposition, affecting the stack periodicity and a reduced aluminium content of the AlGaAs barriers, whereas their widths as well as those of the GaAs quantum wells agreed with the nominal values within one atomic layer. Growth on an offcut substrate led to facets and steps at the interfaces. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  6. Dark-field transmission electron microscopy of cortical bone reveals details of extrafibrillar crystals.

    Science.gov (United States)

    Schwarcz, Henry P; McNally, Elizabeth A; Botton, Gianluigi A

    2014-12-01

    In a previous study we showed that most of the mineral in bone is present in the form of "mineral structures", 5-6nm-thick, elongated plates which surround and are oriented parallel to collagen fibrils. Using dark-field transmission electron microscopy, we viewed mineral structures in ion-milled sections of cortical human bone cut parallel to the collagen fibrils. Within the mineral structures we observe single crystals of apatite averaging 5.8±2.7nm in width and 28±19nm in length, their long axes oriented parallel to the fibril axis. Some appear to be composite, co-aligned crystals as thin as 2nm. From their similarity to TEM images of crystals liberated from deproteinated bone we infer that we are viewing sections through platy crystals of apatite that are assembled together to form the mineral structures. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Transmission electron microscopy of oxide dispersion strengthened (ODS) molybdenum: effects of irradiation on material microstructure

    International Nuclear Information System (INIS)

    Baranwal, R.; Burke, M.G.

    2003-01-01

    Oxide dispersion strengthened (ODS) molybdenum has been characterized using transmission electron microscopy (TEM) to determine the effects of irradiation on material microstructure. This work describes the results-to-date from TEM characterization of unirradiated and irradiated ODS molybdenum. The general microstructure of the unirradiated material consists of fine molybdenum grains (< 5 (micro)m average grain size) with numerous low angle boundaries and isolated dislocation networks. 'Ribbon'-like lanthanum oxides are aligned along the working direction of the product form and are frequently associated with grain boundaries, serving to inhibit grain boundary and dislocation movement. In addition to the 'ribbons', discrete lanthanum oxide particles have also been detected. After irradiation, the material is characterized by the presence of nonuniformly distributed large (∼ 20 to 100 nm in diameter), multi-faceted voids, while the molybdenum grain size and oxide morphology appear to be unaffected by irradiation

  8. Transmission electron microscope studies of laser and thermally annealed ion implanted silicon

    International Nuclear Information System (INIS)

    Narayan, J.; Young, R.T.; White, C.W.

    1978-01-01

    Transmission electron microscopy has been used to study the effects of high power laser pulses on boron, phosphorous and arsenic implanted [100] silicon crystals. No defects (dislocations, dislocation loops and/or stacking faults) were observed in either as-grown or implanted silicon after one pulse of ruby laser irradiation (lambda = 0.694 μm, pulse energy density 1.5 to 1.8 J cm -2 , 50 x 10 -9 pulse duration time). The concentration of boron in solution, as inferred from electrical measurements, could exceed the equilibrium solubility. In thermally annealed specimens, on the other hand, significant damage remained even after annealing at 1100 0 C for 30 minutes. On thermally annealing the implanted, laser-treated specimens, precipitation of the implanted boron ions occurred whenever the implanted doses were in excess of the equilibrium solubility limits. The relationship of these observations to the results of electrical measurements made on these samples will be discussed

  9. Specimen preparation for correlating transmission electron microscopy and atom probe tomography of mesoscale features.

    Science.gov (United States)

    Hartshorne, Matthew I; Isheim, Dieter; Seidman, David N; Taheri, Mitra L

    2014-12-01

    Atom-probe tomography (APT) provides atomic-scale spatial and compositional resolution that is ideally suited for the analysis of grain boundaries. The small sample volume analyzed in APT presents, however, a challenge for capturing mesoscale features, such as grain boundaries. A new site-specific method utilizing transmission electron microscopy (TEM) for the precise selection and isolation of mesoscale microstructural features in a focused-ion-beam (FIB) microscope lift-out sample, from below the original surface of the bulk sample, for targeted preparation of an APT microtip by FIB-SEM microscopy is presented. This methodology is demonstrated for the targeted extraction of a prior austenite grain boundary in a martensitic steel alloy; it can, however, be easily applied to other mesoscale features, such as heterophase interfaces, precipitates, and the tips of cracks. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. In-situ environmental (scanning) transmission electron microscopy of catalysts at the atomic level

    International Nuclear Information System (INIS)

    Gai, P L; Boyes, E D

    2014-01-01

    Observing reacting single atoms on the solid catalyst surfaces under controlled reaction conditions is a key goal in understanding and controlling heterogeneous catalytic reactions. In-situ real time aberration corrected environmental (scanning) transmission electron microscopy (E(S)TEM permit the direct imaging of dynamic surface and sub-surface structures of reacting catalysts. In this paper in-situ AC ETEM and AC ESTEM studies under controlled reaction environments of oxide catalysts and supported metal nanocatalysts important in chemical industry are presented. They provide the direct evidence of dynamic processes at the oxide catalyst surface at the atomic scale and single atom dynamics in catalytic reactions. The ESTEM studies of single atom dynamics in controlled reaction environments show that nanoparticles act as reservoirs of ad-atoms. The results have important implications in catalysis and nanoparticle studies

  11. In Situ Transmission Electron Microscopy Observation of Nanostructural Changes in Phase-Change Memory

    KAUST Repository

    Meister, Stefan

    2011-04-26

    Phase-change memory (PCM) has been researched extensively as a promising alternative to flash memory. Important studies have focused on its scalability, switching speed, endurance, and new materials. Still, reliability issues and inconsistent switching in PCM devices motivate the need to further study its fundamental properties. However, many investigations treat PCM cells as black boxes; nanostructural changes inside the devices remain hidden. Here, using in situ transmission electron microscopy, we observe real-time nanostructural changes in lateral Ge2Sb2Te5 (GST) PCM bridges during switching. We find that PCM devices with similar resistances can exhibit distinct threshold switching behaviors due to the different initial distribution of nanocrystalline and amorphous domains, explaining variability of switching behaviors of PCM cells in the literature. Our findings show a direct correlation between nanostructure and switching behavior, providing important guidelines in the design and operation of future PCM devices with improved endurance and lower variability. © 2011 American Chemical Society.

  12. A new method to characterize dopant profiles in NMOSFETs using conventional transmission electron microscopy

    International Nuclear Information System (INIS)

    Kawamura, Kazuo; Ikeda, Kazuto; Terauchi, Masami

    2004-01-01

    We have developed a new method using conventional transmission electron microscopy (TEM) to obtain two dimensional dopant profiles in silicon and applied it to 40 nm-gate-length N + /p metal oxide semiconductor field effect transistors (MOSFETs). The results are consistent with those of selective-chemically etched samples observed by TEM. This method, using focused ion beam (FIB) sample preparation and conventional TEM, has the great advantage of simple sample preparation and high spatial resolution compared to other characterization methods, such as atomic capacitance microscopy, spreading resistance microscopy, and TEM combined with selective chemical etching. This indicates that this method can be applicable to the analysis of FETs at the 65 nm or smaller node

  13. Cross-sectional transmission electron microscopy observation of Nb/AlOx-Al/Nb Josephson junctions

    International Nuclear Information System (INIS)

    Imamura, T.; Hasuo, S.

    1991-01-01

    A study of microstructure of Nb/AlO x -Al/Nb Josephson junctions by cross-sectional transmission electron microscopy yielded much information regarding the junction barrier region. Both thick Nb and several-nanometer Al form polycrystalline films with columnar structures. Nb is oriented to the (110) plane, and Al is (111). The 200 nm lower Nb has a wavy surface with ∼5 nm smoothness, but its surface is planarized by several nanometers Al deposited on it. Thus AlO x with a smoothness under 1 nm can be formed on Al. The upper Nb has a good crystalline structure even just above the AlO x barrier

  14. Light-Induced Reduction of Cuprous Oxide in an Environmental Transmission Electron Microscope

    DEFF Research Database (Denmark)

    Cavalca, Filippo Carlo; Laursen, Anders Bo; Wagner, Jakob Birkedal

    2013-01-01

    Photocatalysts for solar fuel production are subject to intensive investigation as they constitute one viable route for solar energy harvesting. Cuprous oxide (Cu2O) is a working photocatalyst for hydrogen evolution but it photocorrodes upon light illumination in an aqueous environment. Environme......Photocatalysts for solar fuel production are subject to intensive investigation as they constitute one viable route for solar energy harvesting. Cuprous oxide (Cu2O) is a working photocatalyst for hydrogen evolution but it photocorrodes upon light illumination in an aqueous environment....... Environmental transmission electron microscopy (ETEM) makes it possible to obtain insight into the local structure, composition and reactivity of catalysts in their working environment, which is of fundamental interest for sustainable energy research and is essential for further material optimization. Herein......, photoreduction of Cu2O is studied in situ using a dedicated TEM specimen holder for light illumination....

  15. Modeling of temperature profiles in an environmental transmission electron microscope using computational fluid dynamics

    DEFF Research Database (Denmark)

    Mortensen, Peter Mølgaard; Jensen, Anker Degn; Hansen, Thomas Willum

    2015-01-01

    The temperature and velocity field, pressure distribution, and the temperature variation across the sample region inside an environmental transmission electron microscope (ETEM) have been modeled by means of computational fluid dynamics (CFD). Heating the sample area by a furnace type TEM holder...... gives rise to temperature gradients over the sample area. Three major mechanisms have been identified with respect to heat transfer in the sample area: radiation from the grid, conduction in the grid, and conduction in the gas. A parameter sensitivity analysis showed that the sample temperature...... was affected by the conductivity of the gas, the emissivity of the sample grid, and the conductivity of the grid. Ideally the grid should be polished and made from a material with good conductivity, e.g. copper. With hydrogen gas, which has the highest conductivity of the gases studied, the temperature...

  16. Midgut ultrastructure of the third instar of Dermatobia hominis (Diptera: Cuterebridae) based on transmission electron microscopy.

    Science.gov (United States)

    Evangelista, L G; Leite, A C R

    2003-03-01

    The midgut ultrastucture of the third-instar of Dermatobia hominis (L., Jr.) was investigated using transmission electron microscopy (TEM). The tubular midgut bears a monolayer of epithelial cells with the plasma membrane showing multiple folding where it adjoins the basement membrane. Septate junctions bound the epithelial cells on each side. These cells have electrolucent cytoplasm containing mitochondria, vacuoles, rough and smooth endoplasmic reticula, lamellar bodies, and a prominent nucleus with dispersed chromatin. The peritrophic matrix is close to elongate microvilli, which are sometimes forked. Regenerative cells, in an undifferentiated state when closest to the basement membrane, are scattered throughout the epithelial cells. A thick basement membrane, surrounded by thick connective tissue including muscle, tracheal tubes, and extracellular matrix is linked to epithelial cells by hemidesmosome-like structures. Entero-endocrine, goblet or cuprophilic cells were not observed.

  17. Transmission electron microscopy and electrical properties measurements of laser doped silicon and GaAs

    International Nuclear Information System (INIS)

    Young, R.T.; Narayan, J.; Westbrook, R.D.; Wood, R.F.

    1978-12-01

    High quality silicon p-n junctions have been prepared by alloying a vacuum evaporated Al film into n-type Si and by epitaxial regrowth of an As doped Si amorphous layer onto p-type (100) Si by a single short pulse of ruby laser radiation. Transmission electron microscopy investigations indicated that a defect-free epitaxial layer was grown on the (100) Si surface; however, some polycrystalline structure in the very near-surface region was observed, which does not seem to affect the junction characteristics. Laser assisted junction formation in GaAs was demonstrated by alloying Mg films into n-type GaAs; however, diode characteristics show a large leakage current which may have been caused by the surface damage

  18. Low temperature calorimetry and transmission electron microscopy of helium bubbles in Cu

    International Nuclear Information System (INIS)

    Syskakis, E.

    1985-08-01

    Helium has been introduced into 100 μm thick pure Cu specimens by implantation of α-particles at T = 300 K. Post-implantation annealing of the specimens at high temperatures caused helium to precipitate into bubbles. We have measured the low-temperature heat capacity of helium confined in bubbles of average radius of less than 100 A. The size of the bubbles was obtained by transmission electron microscope investigations. We have observed that helium liquifies at low temperatures and undergoes the transition to the superfluid state in bubbles of average radius larger than 35 A. The confining geometry of bubbles is new and possesses unique features for investigations of confined helium. It provides the possibility to study properties of extremely small, spherical, completely isolated Bose ''particles'' consisting of 10 4 helium atoms each. Furthermore, as we show, it can be known with better accuracy than formerly investigated confining geometries. (orig./BHO)

  19. Transmission electron microscopy study of stacking faults and their interaction with pyramidal dislocations in deformed Mg

    International Nuclear Information System (INIS)

    Li, B.; Yan, P.F.; Sui, M.L.; Ma, E.

    2010-01-01

    We present transmission electron microscopy (TEM) observations of stacking faults (SFs) and their interactions with pyramidal dislocations, in plastically deformed polycrystalline pure magnesium. We have observed well-defined fringes as well as streaking in diffraction patterns, typical of SFs. The basal SFs are decorated by a large number of dark speckles, which are created by the interaction with pyramidal dislocations that have both and components as revealed by our contrast analysis. The SFs do not appear to result from the splitting of unit dislocations, as the SFs are relatively wide and no dislocation nodes were observed. By tilting the specimen systematically inside TEM, the SFs and the associated dislocations in Mg are found to exhibit a rich variety of features in terms of their morphology and diffraction contrast.

  20. Avoiding drying-artifacts in transmission electron microscopy: Characterizing the size and colloidal state of nanoparticles

    Science.gov (United States)

    Michen, Benjamin; Geers, Christoph; Vanhecke, Dimitri; Endes, Carola; Rothen-Rutishauser, Barbara; Balog, Sandor; Petri-Fink, Alke

    2015-01-01

    Standard transmission electron microscopy nanoparticle sample preparation generally requires the complete removal of the suspending liquid. Drying often introduces artifacts, which can obscure the state of the dispersion prior to drying and preclude automated image analysis typically used to obtain number-weighted particle size distribution. Here we present a straightforward protocol for prevention of the onset of drying artifacts, thereby allowing the preservation of in-situ colloidal features of nanoparticles during TEM sample preparation. This is achieved by adding a suitable macromolecular agent to the suspension. Both research- and economically-relevant particles with high polydispersity and/or shape anisotropy are easily characterized following our approach (http://bsa.bionanomaterials.ch), which allows for rapid and quantitative classification in terms of dimensionality and size: features that are major targets of European Union recommendations and legislation. PMID:25965905

  1. Signal processing of high-resolution transmission electron microscope images using Fourier transforms

    Energy Technology Data Exchange (ETDEWEB)

    Buseck, P.R.; Epelboin, Y.; Rimsky, A.

    1988-11-01

    Interpretation of images obtained by high-resolution transmission electron microscopy (HRTEM) can be aided by the use of processed signals. Images are recorded digitally or are digitized from a photograph, and then these data are Fourier transformed and treated. The low- and high-frequency signals are removed, and a variety of circular and elliptical (anisotropic) apertures or screens are applied to explore and highlight features of special interest. A minicomputer can be used to perform such image processing rapidly, interactively, and with high precision. Elliptical filters are of special interest for the examination of linear or planar features such as the distribution of stacking faults or the presence and distribution of superstructures. Some superstructures themselves contain defects, and these can similarly be highlighted and examined. The uses of processing for examining HRTEM images of layering in a complex sheet silicate mineral and dislocation cores in grossular garnet are illustrated.

  2. Transmission electron microscopy reveals distinct macrophage- and tick cell-specific morphological stages of Ehrlichia chaffeensis.

    Directory of Open Access Journals (Sweden)

    Sarah E Dedonder

    Full Text Available BACKGROUND: Ehrlichia chaffeensis is an emerging tick-borne rickettsial pathogen responsible for human monocytic ehrlichiosis. Despite the induction of an active host immune response, the pathogen has evolved to persist in its vertebrate and tick hosts. Understanding how the organism progresses in tick and vertebrate host cells is critical in identifying effective strategies to block the pathogen transmission. Our recent molecular and proteomic studies revealed differences in numerous expressed proteins of the organism during its growth in different host environments. METHODOLOGY/PRINCIPAL FINDINGS: Transmission electron microscopy analysis was performed to assess morphological changes in the bacterium within macrophages and tick cells. The stages of pathogen progression observed included the attachment of the organism to the host cells, its engulfment and replication within a morulae by binary fission and release of the organisms from infected host cells by complete host cell lysis or by exocytosis. E. chaffeensis grown in tick cells was highly pleomorphic and appears to replicate by both binary fission and filamentous type cell divisions. The presence of Ehrlichia-like inclusions was also observed within the nucleus of both macrophages and tick cells. This observation was confirmed by confocal microscopy and immunoblot analysis. CONCLUSIONS/SIGNIFICANCE: Morphological differences in the pathogen's progression, replication, and processing within macrophages and tick cells provide further evidence that E. chaffeensis employs unique host-cell specific strategies in support of adaptation to vertebrate and tick cell environments.

  3. Combined scanning transmission X-ray and electron microscopy for the characterization of bacterial endospores.

    Science.gov (United States)

    Jamroskovic, Jan; Shao, Paul P; Suvorova, Elena; Barak, Imrich; Bernier-Latmani, Rizlan

    2014-09-01

    Endospores (also referred to as bacterial spores) are bacterial structures formed by several bacterial species of the phylum Firmicutes. Spores form as a response to environmental stress. These structures exhibit remarkable resistance to harsh environmental conditions such as exposure to heat, desiccation, and chemical oxidants. The spores include several layers of protein and peptidoglycan that surround a core harboring DNA as well as high concentrations of calcium and dipicolinic acid (DPA). A combination of scanning transmission X-ray microscopy, scanning transmission electron microscopy, and energy dispersive spectroscopy was used for the direct quantitative characterization of bacterial spores. The concentration and localization of DPA, Ca(2+) , and other elements were determined and compared for the core and cortex of spores from two distinct genera: Bacillus subtilis and Desulfotomaculum reducens. This micro-spectroscopic approach is uniquely suited for the direct study of individual bacterial spores, while classical molecular and biochemical methods access only bulk characteristics. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  4. Effect of Charging Electron Exposure on 1064nm Transmission Through Bare Sapphire Optics and SiO2 over HfO2 AR-Coated Sapphire Optics

    Science.gov (United States)

    Ottens, Brian P.; Connelly, Joseph; Brown, Stephen; Roeder, James; Kauder, Lonny; Cavanaugh, John

    2010-01-01

    Experiments measuring the effect of electron exposure on 1064nm transmission for optical sapphire were conducted. Detailed before and after inspections did not identify any resulting Litchenburg patterns. Pre- and post-exposure 1064nm transmission measurements are compared.

  5. 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

  6. Validities of three multislice algorithms for quantitative low-energy transmission electron microscopy.

    Science.gov (United States)

    Ming, W Q; Chen, J H

    2013-11-01

    Three different types of multislice algorithms, namely the conventional multislice (CMS) algorithm, the propagator-corrected multislice (PCMS) algorithm and the fully-corrected multislice (FCMS) algorithm, have been evaluated in comparison with respect to the accelerating voltages in transmission electron microscopy. Detailed numerical calculations have been performed to test their validities. The results show that the three algorithms are equivalent for accelerating voltage above 100kV. However, below 100 kV, the CMS algorithm will introduce significant errors, not only for higher-order Laue zone (HOLZ) reflections but also for zero-order Laue zone (ZOLZ) reflections. The differences between the PCMS and FCMS algorithms are negligible and mainly appear in HOLZ reflections. Nonetheless, when the accelerating voltage is further lowered to 20 kV or below, the PCMS algorithm will also yield results deviating from the FCMS results. The present study demonstrates that the propagation of the electron wave from one slice to the next slice is actually cross-correlated with the crystal potential in a complex manner, such that when the accelerating voltage is lowered to 10 kV, the accuracy of the algorithms is dependent of the scattering power of the specimen. © 2013 Elsevier B.V. All rights reserved.

  7. Transmission electron microscopy as a tool for nanocrystal characterization pre- and post-injector.

    Science.gov (United States)

    Stevenson, H P; DePonte, D P; Makhov, A M; Conway, James F; Zeldin, O B; Boutet, S; Calero, G; Cohen, A E

    2014-07-17

    Recent advancements at the Linac Coherent Light Source X-ray free-electron laser (XFEL) enabling successful serial femtosecond diffraction experiments using nanometre-sized crystals (NCs) have opened up the possibility of X-ray structure determination of proteins that produce only submicrometre crystals such as many membrane proteins. Careful crystal pre-characterization including compatibility testing of the sample delivery method is essential to ensure efficient use of the limited beamtime available at XFEL sources. This work demonstrates the utility of transmission electron microscopy for detecting and evaluating NCs within the carrier solutions of liquid injectors. The diffraction quality of these crystals may be assessed by examining the crystal lattice and by calculating the fast Fourier transform of the image. Injector reservoir solutions, as well as solutions collected post-injection, were evaluated for three types of protein NCs (i) the membrane protein PTHR1, (ii) the multi-protein complex Pol II-GFP and (iii) the soluble protein lysozyme. Our results indicate that the concentration and diffraction quality of NCs, particularly those with high solvent content and sensitivity to mechanical manipulation may be affected by the delivery process. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  8. Immunogold Staining of London Resin (LR) White Sections for Transmission Electron Microscopy (TEM).

    Science.gov (United States)

    Skepper, Jeremy N; Powell, Janet M

    2008-06-01

    INTRODUCTIONIn post-embedding methods of immunogold staining, the cells or tissues are fixed chemically or cryoimmobilized, dehydrated, and embedded in epoxy or acrylic resins. Thin sections (50-70 nm in thickness) are cut using an ultramicrotome with a diamond knife, using a water bath to collect the sections as they slide off the knife. The sections are stretched with solvent vapor or a heat source and collected onto either bare or plastic-coated nickel grids. The sections are then stained immunochemically with primary antibodies raised against antigens exposed on the surface of the sections. The primary antibodies are visualized by staining immunochemically with secondary antibodies raised against the species and isotype of the primary antibodies, conjugated to colloidal gold particles. The immunochemically stained sections are then contrast stained with salts of uranium (uranyl acetate) and lead (lead citrate) to reveal the ultrastructure of the cells, and are finally viewed by transmission electron microscopy (TEM). LR White was introduced as a low-toxicity alternative to epoxy resins, which frequently contained carcinogens. Unlike the simplest acrylic resins, in which monomers are polymerized to form long chains, the LR resins contain aromatic cross-linkers to improve the stability of the sections under the electron beam. LR White and Gold both have very low viscosity and readily penetrate, even into dense tissue. In this protocol, aldehyde-fixed tissue is dehydrated in ethanol, impregnated in LR White resin and polymerized under vacuum or in a nitrogen atmosphere before sectioning and immunogold staining.

  9. The core contribution of transmission electron microscopy to functional nanomaterials engineering.

    Science.gov (United States)

    Carenco, Sophie; Moldovan, Simona; Roiban, Lucian; Florea, Ileana; Portehault, David; Vallé, Karine; Belleville, Philippe; Boissière, Cédric; Rozes, Laurence; Mézailles, Nicolas; Drillon, Marc; Sanchez, Clément; Ersen, Ovidiu

    2016-01-21

    Research on nanomaterials and nanostructured materials is burgeoning because their numerous and versatile applications contribute to solve societal needs in the domain of medicine, energy, environment and STICs. Optimizing their properties requires in-depth analysis of their structural, morphological and chemical features at the nanoscale. In a transmission electron microscope (TEM), combining tomography with electron energy loss spectroscopy and high-magnification imaging in high-angle annular dark-field mode provides access to all features of the same object. Today, TEM experiments in three dimensions are paramount to solve tough structural problems associated with nanoscale matter. This approach allowed a thorough morphological description of silica fibers. Moreover, quantitative analysis of the mesoporous network of binary metal oxide prepared by template-assisted spray-drying was performed, and the homogeneity of amino functionalized metal-organic frameworks was assessed. Besides, the morphology and internal structure of metal phosphide nanoparticles was deciphered, providing a milestone for understanding phase segregation at the nanoscale. By extrapolating to larger classes of materials, from soft matter to hard metals and/or ceramics, this approach allows probing small volumes and uncovering materials characteristics and properties at two or three dimensions. Altogether, this feature article aims at providing (nano)materials scientists with a representative set of examples that illustrates the capabilities of modern TEM and tomography, which can be transposed to their own research.

  10. Defects in paramagnetic Co-doped ZnO films studied by transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kovács, A.; Duchamp, M.; Boothroyd, C. B.; Dunin-Borkowski, R. E. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich (Germany); Ney, A.; Ney, V. [Institut für Halbleiter- und Festkörperphysik, Johannes Kepler Universität, Altenberger Str. 69, 4040 Linz (Austria); Galindo, P. L. [Departamento de Ingeniería Informática, Universidad de Cádiz, 11510 Cádiz (Spain); Kaspar, T. C.; Chambers, S. A. [Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354 (United States)

    2013-12-28

    We study planar defects in epitaxial Co:ZnO dilute magnetic semiconductor thin films deposited on c-plane sapphire (Al{sub 2}O{sub 3}), as well as the Co:ZnO/Al{sub 2}O{sub 3} interface, using aberration-corrected transmission electron microscopy and electron energy-loss spectroscopy. Co:ZnO samples that were deposited using pulsed laser deposition and reactive magnetron sputtering are both found to contain extrinsic stacking faults, incoherent interface structures, and compositional variations within the first 3–4 Co:ZnO layers next to the Al{sub 2}O{sub 3} substrate. The stacking fault density is in the range of 10{sup 17} cm{sup −3}. We also measure the local lattice distortions around the stacking faults. It is shown that despite the relatively high density of planar defects, lattice distortions, and small compositional variation, the Co:ZnO films retain paramagnetic properties.

  11. Determination of domain wall chirality using in situ Lorentz transmission electron microscopy

    Directory of Open Access Journals (Sweden)

    Jordan J. Chess

    2017-05-01

    Full Text Available Controlling domain wall chirality is increasingly seen in non-centrosymmetric materials. Mapping chiral magnetic domains requires knowledge about all the vector components of the magnetization, which poses a problem for conventional Lorentz transmission electron microscopy (LTEM that is only sensitive to magnetic fields perpendicular to the electron beams direction of travel. The standard approach in LTEM for determining the third component of the magnetization is to tilt the sample to some angle and record a second image. This presents a problem for any domain structures that are stabilized by an applied external magnetic field (e.g. skyrmions, because the standard LTEM setup does not allow independent control of the angle of an applied magnetic field, and sample tilt angle. Here we show that applying a modified transport of intensity equation analysis to LTEM images collected during an applied field sweep, we can determine the domain wall chirality of labyrinth domains in a perpendicularly magnetized material, avoiding the need to tilt the sample.

  12. 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

  13. Preferred diffusion paths for copper electromigration by in situ transmission electron microscopy.

    Science.gov (United States)

    Oh, Young-Hwa; Kim, Sung-Il; Kim, Miyoung; Lee, Seung-Yong; Kim, Young-Woon

    2017-10-01

    Ionic transport in the reverse direction of an electric field is caused by momentum transfer from free electrons to metal ions, i.e., electromigration (EM), which is a critical factor leading to copper (Cu) interconnect failure in integrated circuits under extreme operating conditions. We investigated Cu self-diffusion paths under electrical bias using in situ transmission electron microscopy (TEM). An electric current was applied to multigrain Cu lines in the TEM instrument for durations of up to the order of 10 4 s to trace EM-induced Cu movement around voids and hillocks. Combining this approach with scanning nanobeam diffraction, we observed that high-angle grain boundaries exposed to the free surface are the most favored paths for Cu EM, rather than a specific orientation within the grain. On hillocks of accumulated Cu atoms, we directly observed grain growth, accompanied by the formation of Σ7 high-mobile and Σ3 twin coincidence site lattice boundaries for effective growth. This study provides insight into the EM mechanism to improve the reliability of metal interconnect design. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Investigating fold structures of 2D materials by quantitative transmission electron microscopy.

    Science.gov (United States)

    Wang, Zhiwei; Zhang, Zengming; Liu, Wei; Wang, Zhong Lin

    2017-04-01

    We report an approach developed for deriving 3D structural information of 2D membrane folds based on the recently-established quantitative transmission electron microscopy (TEM) in combination with density functional theory (DFT) calculations. Systematic multislice simulations reveal that the membrane folding leads to sufficiently strong electron scattering which enables a precise determination of bending radius. The image contrast depends also on the folding angles of 2D materials due to the variation of projection potentials, which however exerts much smaller effect compared with the bending radii. DFT calculations show that folded edges are typically characteristic of (fractional) nanotubes with the same curvature retained after energy optimization. Owing to the exclusion of Stobbs factor issue, numerical simulations were directly used in comparison with the experimental measurements on an absolute contrast scale, which results in a successful determination of bending radius of folded monolayer MoS 2 films. The method should be applicable to characterizing all 2D membranes with 3D folding features. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Nature and evolution of incommensurate charge order in manganites visualized with cryogenic scanning transmission electron microscopy.

    Science.gov (United States)

    El Baggari, Ismail; Savitzky, Benjamin H; Admasu, Alemayehu S; Kim, Jaewook; Cheong, Sang-Wook; Hovden, Robert; Kourkoutis, Lena F

    2018-02-13

    Incommensurate charge order in hole-doped oxides is intertwined with exotic phenomena such as colossal magnetoresistance, high-temperature superconductivity, and electronic nematicity. Here, we map, at atomic resolution, the nature of incommensurate charge-lattice order in a manganite using scanning transmission electron microscopy at room temperature and cryogenic temperature ([Formula: see text]93 K). In diffraction, the ordering wave vector changes upon cooling, a behavior typically associated with incommensurate order. However, using real space measurements, we discover that the ordered state forms lattice-locked regions over a few wavelengths interspersed with phase defects and changing periodicity. The cations undergo picometer-scale ([Formula: see text]6 pm to 11 pm) transverse displacements, suggesting that charge-lattice coupling is strong. We further unearth phase inhomogeneity in the periodic lattice displacements at room temperature, and emergent phase coherence at 93 K. Such local phase variations govern the long-range correlations of the charge-ordered state and locally change the periodicity of the modulations, resulting in wave vector shifts in reciprocal space. These atomically resolved observations underscore the importance of lattice coupling and phase inhomogeneity, and provide a microscopic explanation for putative "incommensurate" order in hole-doped oxides. Copyright © 2018 the Author(s). Published by PNAS.

  16. Assessment of microcrystal quality by transmission electron microscopy for efficient serial femtosecond crystallography.

    Science.gov (United States)

    Barnes, Christopher O; Kovaleva, Elena G; Fu, Xiaofeng; Stevenson, Hilary P; Brewster, Aaron S; DePonte, Daniel P; Baxter, Elizabeth L; Cohen, Aina E; Calero, Guillermo

    2016-07-15

    Serial femtosecond crystallography (SFX) employing high-intensity X-ray free-electron laser (XFEL) sources has enabled structural studies on microcrystalline protein samples at non-cryogenic temperatures. However, the identification and optimization of conditions that produce well diffracting microcrystals remains an experimental challenge. Here, we report parallel SFX and transmission electron microscopy (TEM) experiments using fragmented microcrystals of wild type (WT) homoprotocatechuate 2,3-dioxygenase (HPCD) and an active site variant (H200Q). Despite identical crystallization conditions and morphology, as well as similar crystal size and density, the indexing efficiency of the diffraction data collected using the H200Q variant sample was over 7-fold higher compared to the diffraction results obtained using the WT sample. TEM analysis revealed an abundance of protein aggregates, crystal conglomerates and a smaller population of highly ordered lattices in the WT sample as compared to the H200Q variant sample. While not reported herein, the 1.75 Å resolution structure of the H200Q variant was determined from ∼16 min of beam time, demonstrating the utility of TEM analysis in evaluating sample monodispersity and lattice quality, parameters critical to the efficiency of SFX experiments. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Automated detection of synapses in serial section transmission electron microscopy image stacks.

    Directory of Open Access Journals (Sweden)

    Anna Kreshuk

    Full Text Available We describe a method for fully automated detection of chemical synapses in serial electron microscopy images with highly anisotropic axial and lateral resolution, such as images taken on transmission electron microscopes. Our pipeline starts from classification of the pixels based on 3D pixel features, which is followed by segmentation with an Ising model MRF and another classification step, based on object-level features. Classifiers are learned on sparse user labels; a fully annotated data subvolume is not required for training. The algorithm was validated on a set of 238 synapses in 20 serial 7197×7351 pixel images (4.5×4.5×45 nm resolution of mouse visual cortex, manually labeled by three independent human annotators and additionally re-verified by an expert neuroscientist. The error rate of the algorithm (12% false negative, 7% false positive detections is better than state-of-the-art, even though, unlike the state-of-the-art method, our algorithm does not require a prior segmentation of the image volume into cells. The software is based on the ilastik learning and segmentation toolkit and the vigra image processing library and is freely available on our website, along with the test data and gold standard annotations (http://www.ilastik.org/synapse-detection/sstem.

  18. Collagen Fibrils and Proteoglycans of Macular Dystrophy Cornea: Ultrastructure and 3D Transmission Electron Tomography.

    Science.gov (United States)

    Akhtar, Saeed; Alkatan, Hind M; Kirat, Omar; Khan, Adnan A; Almubrad, Turki

    2015-06-01

    We report the ultrastructure and 3D transmission electron tomography of collagen fibrils (CFs), proteoglycans (PGs), and microfibrils within the CF of corneas of patients with macular corneal dystrophy (MCD). Three normal corneas and three MCD corneas from three Saudi patients (aged 25, 31, and 49 years, respectively) were used for this study. The corneas were processed for light and electron microscopy studies. 3D images were composed from a set of 120 ultrastructural images using the program "Composer" and visualized using the program "Visuliser Kai". 3D image analysis of MCD cornea showed a clear organization of PGs around the CF at very high magnification and degeneration of the microfibrils within the CF. Within the MCD cornea, the PG area in the anterior stroma was significantly larger than in the middle and posterior stroma. The PG area in the MCD cornea was significantly larger compared with the PG area in the normal cornea. The CF diameter and inter-fibrillar spacing of the MCD cornea were significantly smaller compared with those of the normal cornea. Ultrastructural 3D imaging showed that the production of unsulfated keratin sulfate (KS) may lead to the degeneration of micro-CFs within the CFs. The effect of the unsulfated KS was higher in the anterior stroma compared with the posterior stroma.

  19. Light and transmission electron microscopy of Cepedea longa (Opalinidae from Fejervarya limnocharis

    Directory of Open Access Journals (Sweden)

    Li Can

    2017-01-01

    Full Text Available Cepedea longa Bezzenberger, 1904, collected from Fejervarya limnocharis (Amphibia, Anura, Ranidae from Honghu Lake, Hubei Province, China in May–July 2016, is described at both light and transmission electron microscope levels. This is the first electron microscopic study of this species. Cepedea longa possesses a developed fibrillar skeletal system, composed of longitudinal fibrillar bands and transversal fibrils as well as numerous thin microfibrils dispersed in the endoplasm, which may play an important role in morphogenesis and offer some resilience to deformations of the cell. Longitudinal microfibrils are polarizing elements of kineties, bordering the somatic kineties on the left side and possibly responsible for kinetosome alignment. Two types of vesicles exist in the somatic cortex: globular endocytotic vesicles and flattened exocytotic vesicles. As to the nuclei of C. longa, a thick microfibrillar layer was observed to attach to the cytoplasmic face of the nuclear envelope. This fact suggests no necessary connection between the presence of this microfibrillar layer and the number of nuclei. In addition, some unknown tightly-packed microtubular structures in the nucleoplasm were observed for the first time in opalinids; neither their nature nor physiological significance is known. A detailed list of all reported Cepedea species is included.

  20. Observation of ionomer in catalyst ink of polymer electrolyte fuel cell using cryogenic transmission electron microscopy

    International Nuclear Information System (INIS)

    Takahashi, Shinichi; Shimanuki, Junichi; Mashio, Tetsuya; Ohma, Atsushi; Tohma, Hajime; Ishihara, Ayumi; Ito, Yoshiko; Nishino, Yuri; Miyazawa, Atsuo

    2017-01-01

    Optimizing the catalyst layer structure is one of the key issues for improving performance despite lower platinum loading. The catalyst ink, consisting of platinum-loaded carbon particles and ionomer dispersed in an aqueous solvent, is a key factor for controlling the structure of the catalyst layer because the catalyst layer is prepared in a wet coating process. For that purpose, we visualized the nanostructure of the ionomer in the catalyst ink by cryogenic electron microscopy, especially cryogenic transmission electron microscopy (cryo-TEM). By cryo-TEM, it was revealed that ionomer molecules formed rod-like aggregates macro-homogeneously in the solvent, and a similar morphology was observed in a carbon-particle-containing solvent. In contrast, ionomer aggregates in the catalyst ink containing platinum nanoparticles loaded on carbon particles were denser in the vicinity of the platinum-loaded carbon particles. That can be attributed to strong interaction between platinum nanoparticles and sulfonic acid groups in the ionomer. It also implies that a good understanding of ionomer morphology in the catalyst ink can play an important role in controlling the catalyst layer microstructure for reducing platinum loading.