WorldWideScience

Sample records for resolution electronic resource

  1. Electron microscopy at atomic resolution

    Energy Technology Data Exchange (ETDEWEB)

    Gronsky, R.

    1983-11-01

    The direct imaging of atomic structure in solids has become increasingly easier to accomplish with modern transmission electron microscopes, many of which have an information retrieval limit near 0.2 nm point resolution. Achieving better resolution, particularly with any useful range of specimen tilting, requires a major design effort. This presentation describes the new Atomic Resolution Microscope (ARM), recently put into operation at the Lawrence Berkeley Laboratory. Capable of 0.18 nm or better interpretable resolution over a voltage range of 400 kV to 1000 kV with +- 40/sup 0/ biaxial specimen tilting, the ARM features a number of new electron-optical and microprocessor-control designs. These are highlighted, and its atomic resolution performance demonstrated for a selection of inorganic crystals.

  2. Electron microscopy at atomic resolution

    International Nuclear Information System (INIS)

    Gronsky, R.

    1983-11-01

    The direct imaging of atomic structure in solids has become increasingly easier to accomplish with modern transmission electron microscopes, many of which have an information retrieval limit near 0.2 nm point resolution. Achieving better resolution, particularly with any useful range of specimen tilting, requires a major design effort. This presentation describes the new Atomic Resolution Microscope (ARM), recently put into operation at the Lawrence Berkeley Laboratory. Capable of 0.18 nm or better interpretable resolution over a voltage range of 400 kV to 1000 kV with +- 40 0 biaxial specimen tilting, the ARM features a number of new electron-optical and microprocessor-control designs. These are highlighted, and its atomic resolution performance demonstrated for a selection of inorganic crystals

  3. Electronic Resource Management Systems

    Directory of Open Access Journals (Sweden)

    Mark Ellingsen

    2004-10-01

    Full Text Available Computer applications which deal with electronic resource management (ERM are quite a recent development. They have grown out of the need to manage the burgeoning number of electronic resources particularly electronic journals. Typically, in the early years of e-journal acquisition, library staff provided an easy means of accessing these journals by providing an alphabetical list on a web page. Some went as far as categorising the e-journals by subject and then grouping the journals either on a single web page or by using multiple pages. It didn't take long before it was recognised that it would be more efficient to dynamically generate the pages from a database rather than to continually edit the pages manually. Of course, once the descriptive metadata for an electronic journal was held within a database the next logical step was to provide administrative forms whereby that metadata could be manipulated. This in turn led to demands for incorporating more information and more functionality into the developing application.

  4. High-resolution electron microscopy

    CERN Document Server

    Spence, John C H

    2013-01-01

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

  5. Electronic Resource Management and Design

    Science.gov (United States)

    Abrams, Kimberly R.

    2015-01-01

    We have now reached a tipping point at which electronic resources comprise more than half of academic library budgets. Because of the increasing work associated with the ever-increasing number of e-resources, there is a trend to distribute work throughout the library even in the presence of an electronic resources department. In 2013, the author…

  6. Higher Resolution for Water Resources Studies

    Science.gov (United States)

    Dumenil-Gates, L.

    2009-12-01

    The Earth system science community is providing an increasing range of science results for the benefit of achieving the Millennium Development Goals. In addressing questions such as reducing poverty and hunger, achieving sustainable global development, or by defining adaptation strategies for climate change, one of the key issues will be the quantitative description and understanding of the global water cycle, which will allow useful projections of available future water resources for several decades ahead. The quantities of global water cycle elements that we observe today - and deal with in hydrologic and atmospheric modeling - are already very different from the natural flows as human influence on the water cycle by storage, consumption and edifice has been going on for millennia, and climate change is expected to add more uncertainty. In this case Tony Blair’s comment that perhaps the most worrying problem is climate change does not cover the full story. We shall also have to quantify how the human demand for water resources and alterations of the various elements of the water cycle may proceed in the future: will there be enough of the precious water resource to sustain current and future demands by the various sectors involved? The topics that stakeholders and decision makers concerned with managing water resources are interested in cover a variety of human uses such as agriculture, energy production, ecological flow requirements to sustain biodiversity and ecosystem services, or human cultural aspects, recreation and human well-being - all typically most relevant at the regional or local scales, this being quite different from the relatively large-scale that the IPCC assessment addresses. Halfway through the Millennium process, the knowledge base of the global water cycle is still limited. The sustainability of regional water resources is best assessed through a research program that combines high-resolution climate and hydrologic models for expected

  7. Managing electronic resources a LITA guide

    CERN Document Server

    Weir, Ryan O

    2012-01-01

    Informative, useful, current, Managing Electronic Resources: A LITA Guide shows how to successfully manage time, resources, and relationships with vendors and staff to ensure personal, professional, and institutional success.

  8. Electronic Resources Management Project Presentation 2012

    KAUST Repository

    Ramli, Rindra M.

    2012-11-05

    This presentation describes the electronic resources management project undertaken by the KAUST library. The objectives of this project is to migrate information from MS Sharepoint to Millennium ERM module. One of the advantages of this migration is to consolidate all electronic resources into a single and centralized location. This would allow for better information sharing among library staff.

  9. Implementing CORAL: An Electronic Resource Management System

    Science.gov (United States)

    Whitfield, Sharon

    2011-01-01

    A 2010 electronic resource management survey conducted by Maria Collins of North Carolina State University and Jill E. Grogg of University of Alabama Libraries found that the top six electronic resources management priorities included workflow management, communications management, license management, statistics management, administrative…

  10. NaI(Tl) electron energy resolution

    CERN Document Server

    Mengesha, W

    2002-01-01

    NaI(Tl) electron energy resolution eta sub e was measured using the Modified Compton Coincidence Technique (MCCT). The MCCT allowed detection of nearly monoenergetic internal electrons resulting from the scattering of incident 662 keV gamma rays within a primary NaI(Tl) detector. Scattered gamma rays were detected using a secondary HPGe detector in a coincidence mode. Measurements were carried out for electron energies ranging from 16 to 438 keV, by varying the scattering angle. Measured HPGe coincidence spectra were deconvolved to determine the scattered energy spectra from the NaI(Tl) detector. Subsequently, the NaI(Tl) electron energy spectra were determined by subtracting the energy of scattered spectra from the incident source energy (662 keV). Using chi-squared minimization, iterative deconvolution of the internal electron energy spectra from the measured NaI(Tl) spectra was then used to determine eta sub e at the electron energy of interest. eta sub e values determined using this technique represent va...

  11. Electronic Resources Management System: Recommendation Report 2017

    KAUST Repository

    Ramli, Rindra M.

    2017-01-01

    This recommendation report provides an overview of the selection process for the new Electronic Resources Management System. The library has decided to move away from Innovative Interfaces Millennium ERM module. The library reviewed 3 system

  12. Electronic Resources Management Project Presentation 2012

    KAUST Repository

    Ramli, Rindra M.

    2012-01-01

    This presentation describes the electronic resources management project undertaken by the KAUST library. The objectives of this project is to migrate information from MS Sharepoint to Millennium ERM module. One of the advantages of this migration

  13. Benchmarking NaI(Tl) Electron Energy Resolution Measurements

    International Nuclear Information System (INIS)

    Mengesha, Wondwosen; Valentine, J D.

    2002-01-01

    A technique for validating electron energy resolution results measured using the modified Compton coincidence technique (MCCT) has been developed. This technique relies on comparing measured gamma-ray energy resolution with calculated values that were determined using the measured electron energy resolution results. These gamma-ray energy resolution calculations were based on Monte Carlo photon transport simulations, the measured NaI(Tl) electron response, a simplified cascade sequence, and the measured electron energy resolution results. To demonstrate this technique, MCCT-measured NaI(Tl) electron energy resolution results were used along with measured gamma-ray energy resolution results from the same NaI(Tl) crystal. Agreement to within 5% was observed for all energies considered between the calculated and measured gamma-ray energy resolution results for the NaI(Tl) crystal characterized. The calculated gamma-ray energy resolution results were also compared with previously published gamma-ray energy resolution measurements with good agreement (<10%). In addition to describing the validation technique that was developed in this study and the results, a brief review of the electron energy resolution measurements made using the MCCT is provided. Based on the results of this study, it is believed that the MCCT-measured electron energy resolution results are reliable. Thus, the MCCT and this validation technique can be used in the future to characterize the electron energy resolution of other scintillators and to determine NaI(Tl) intrinsic energy resolution

  14. PRINCIPLES OF CONTENT FORMATION EDUCATIONAL ELECTRONIC RESOURCE

    Directory of Open Access Journals (Sweden)

    О Ю Заславская

    2017-12-01

    Full Text Available The article considers modern possibilities of information and communication technologies for the design of electronic educational resources. The conceptual basis of the open educational multimedia system is based on the modular architecture of the electronic educational resource. The content of the electronic training module can be implemented in several versions of the modules: obtaining information, practical exercises, control. The regularities in the teaching process in modern pedagogical theory are considered: general and specific, and the principles for the formation of the content of instruction at different levels are defined, based on the formulated regularities. On the basis of the analysis, the principles of the formation of the electronic educational resource are determined, taking into account the general and didactic patterns of teaching.As principles of the formation of educational material for obtaining information for the electronic educational resource, the article considers: the principle of methodological orientation, the principle of general scientific orientation, the principle of systemic nature, the principle of fundamentalization, the principle of accounting intersubject communications, the principle of minimization. The principles of the formation of the electronic training module of practical studies in the article include: the principle of systematic and dose based consistency, the principle of rational use of study time, the principle of accessibility. The principles of the formation of the module for monitoring the electronic educational resource can be: the principle of the operationalization of goals, the principle of unified identification diagnosis.

  15. Electronic Resources Management System: Recommendation Report 2017

    KAUST Repository

    Ramli, Rindra M.

    2017-05-01

    This recommendation report provides an overview of the selection process for the new Electronic Resources Management System. The library has decided to move away from Innovative Interfaces Millennium ERM module. The library reviewed 3 system as potential replacements namely: Proquest 360 Resource Manager, Ex Libris Alma and Open Source CORAL ERMS. After comparing and trialling the systems, it was decided to go for Proquest 360 Resource Manager.

  16. Improved methods for high resolution electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, J.R.

    1987-04-01

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

  17. CHALLENGES OF ELECTRONIC INFORMATION RESOURCES IN ...

    African Journals Online (AJOL)

    This paper discusses the role of policy for proper and efficient library services in the electronic era. It points out some of the possible dangers of embarking in electronic resources without a proper focus at hand. Thus, it calls for today's librarians and policy makers to brainstorm and come up with working policies suitable to ...

  18. Resolution Versus Error for Computational Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Luzi, Lorenzo; Stevens, Andrew; Yang, Hao; Browning, Nigel D.

    2017-07-01

    Images that are collected via scanning transmission electron microscopy (STEM) can be undersampled to avoid damage to the specimen while maintaining resolution [1, 2]. We have used BPFA to impute missing data and reduce noise [3]. The reconstruction is typically evaluated using the peak signal-to-noise ratio (PSNR). This measure is too conservative for STEM images and we propose that the Fourier ring correlation (FRC) is used instead to evaluate the reconstruction. We are not concerned with exact reconstruction of the truth image, and therefore PSNR is a conservative estimation of the quality of the reconstruction. Instead, we are concerned with the visual resolution of the image and whether atoms can be distinguished. We have evaluated the reconstruction of a simulated STEM image using the FRC and compared the results with the PSNR measurements. The FRC captures the resolution of the image and is not affected by a large MSE if the atom peaks are still distinguishable. The noisy and reconstructed images are shown in Figure 1. The simulated STEM image was sampled at 100%, 80%, 40%, and 20% of the original pixels to simulate an undersampled scan. The reconstruction was done using BPFA with a patch size of 10 x 10 and no overlapping patches. Not having overlapping patches produces inferior results but they are still acceptable. The dictionary size is 64 and 30 iterations were completed during each reconstruction. The 100% image was denoised instead of reconstructed. Poisson noise was applied to the simulated image with λ values of 500, 50, and 5 to simulate lower imaging dose. The original simulated STEM image was also included in our calculations and was generated using a dose of 1000. The simulated STEM image is 100 by 100 pixels and has essentially no high frequency components. The image reconstruction tends to smooth the data, also resulting in no high frequency components. This causes the FRC of the two images to be large at higher resolutions and may be

  19. Zeolites - a high resolution electron microscopy study

    International Nuclear Information System (INIS)

    Alfredsson, V.

    1994-10-01

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

  20. Library training to promote electronic resource usage

    DEFF Research Database (Denmark)

    Frandsen, Tove Faber; Tibyampansha, Dativa; Ibrahim, Glory

    2017-01-01

    Purpose: Increasing the usage of electronic resources is an issue of concern for many libraries all over the world. Several studies stress the importance of information literacy and instruction in order to increase the usage. Design/methodology/approach: The present article presents the results...

  1. Dose-dependent high-resolution electron ptychography

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  2. Methodology for Clustering High-Resolution Spatiotemporal Solar Resource Data

    Energy Technology Data Exchange (ETDEWEB)

    Getman, Dan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lopez, Anthony [National Renewable Energy Lab. (NREL), Golden, CO (United States); Mai, Trieu [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dyson, Mark [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-09-01

    In this report, we introduce a methodology to achieve multiple levels of spatial resolution reduction of solar resource data, with minimal impact on data variability, for use in energy systems modeling. The selection of an appropriate clustering algorithm, parameter selection including cluster size, methods of temporal data segmentation, and methods of cluster evaluation are explored in the context of a repeatable process. In describing this process, we illustrate the steps in creating a reduced resolution, but still viable, dataset to support energy systems modeling, e.g. capacity expansion or production cost modeling. This process is demonstrated through the use of a solar resource dataset; however, the methods are applicable to other resource data represented through spatiotemporal grids, including wind data. In addition to energy modeling, the techniques demonstrated in this paper can be used in a novel top-down approach to assess renewable resources within many other contexts that leverage variability in resource data but require reduction in spatial resolution to accommodate modeling or computing constraints.

  3. Atomic resolution three-dimensional electron diffraction microscopy

    International Nuclear Information System (INIS)

    Miao Jianwei; Ohsuna, Tetsu; Terasaki, Osamu; Hodgson, Keith O.; O'Keefe, Michael A.

    2002-01-01

    We report the development of a novel form of diffraction-based 3D microscopy to overcome resolution barriers inherent in high-resolution electron microscopy and tomography. By combining coherent electron diffraction with the oversampling phasing method, we show that the 3D structure of a nanocrystal can be determined ab initio at a resolution of 1 Angstrom from 29 simulated noisy diffraction patterns. This new form of microscopy can be used to image the 3D structures of nanocrystals and noncrystalline samples, with resolution limited only by the quality of sample diffraction

  4. 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....

  5. 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.

  6. Electronic resource management systems a workflow approach

    CERN Document Server

    Anderson, Elsa K

    2014-01-01

    To get to the bottom of a successful approach to Electronic Resource Management (ERM), Anderson interviewed staff at 11 institutions about their ERM implementations. Among her conclusions, presented in this issue of Library Technology Reports, is that grasping the intricacies of your workflow-analyzing each step to reveal the gaps and problems-at the beginning is crucial to selecting and implementing an ERM. Whether the system will be used to fill a gap, aggregate critical data, or replace a tedious manual process, the best solution for your library depends on factors such as your current soft

  7. use of electronic resources by graduate students of the department

    African Journals Online (AJOL)

    respondent's access electronic resources from the internet via Cybercafé .There is a high ... KEY WORDS: Use, Electronic Resources, Graduate Students, Cybercafé. INTRODUCTION ... Faculty of Education, University of Uyo, Uyo. Olu Olat ...

  8. Problem Resolution through Electronic Mail: A Five-Step Model.

    Science.gov (United States)

    Grandgenett, Neal; Grandgenett, Don

    2001-01-01

    Discusses the use of electronic mail within the general resolution and management of administrative problems and emphasizes the need for careful attention to problem definition and clarity of language. Presents a research-based five-step model for the effective use of electronic mail based on experiences at the University of Nebraska at Omaha.…

  9. High Resolution Electron Microscopy in Materials Science

    International Nuclear Information System (INIS)

    Amelinckx, S.

    1986-01-01

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

  10. Optimization of Monochromated TEM for Ultimate Resolution Imaging and Ultrahigh Resolution Electron Energy Loss Spectroscopy

    KAUST Repository

    Lopatin, Sergei; Cheng, Bin; Liu, Wei-Ting; Tsai, Meng-Lin; He, Jr-Hau; Chuvilin, Andrey

    2017-01-01

    The performance of a monochromated transmission electron microscope with Wien type monochromator is optimized to achieve an extremely narrow energy spread of electron beam and an ultrahigh energy resolution with spectroscopy. The energy spread in the beam is improved by almost an order of magnitude as compared to specified values. The optimization involves both the monochromator and the electron energy loss detection system. We demonstrate boosted capability of optimized systems with respect to ultra-low loss EELS and sub-angstrom resolution imaging (in a combination with spherical aberration correction).

  11. Optimization of Monochromated TEM for Ultimate Resolution Imaging and Ultrahigh Resolution Electron Energy Loss Spectroscopy

    KAUST Repository

    Lopatin, Sergei

    2017-09-01

    The performance of a monochromated transmission electron microscope with Wien type monochromator is optimized to achieve an extremely narrow energy spread of electron beam and an ultrahigh energy resolution with spectroscopy. The energy spread in the beam is improved by almost an order of magnitude as compared to specified values. The optimization involves both the monochromator and the electron energy loss detection system. We demonstrate boosted capability of optimized systems with respect to ultra-low loss EELS and sub-angstrom resolution imaging (in a combination with spherical aberration correction).

  12. High-resolution electron microscopy of advanced materials

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-11-01

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

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

    Indian Academy of Sciences (India)

    2001-03-09

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

  14. Sub-micron resolution selected area electron channeling patterns.

    Science.gov (United States)

    Guyon, J; Mansour, H; Gey, N; Crimp, M A; Chalal, S; Maloufi, N

    2015-02-01

    Collection of selected area channeling patterns (SACPs) on a high resolution FEG-SEM is essential to carry out quantitative electron channeling contrast imaging (ECCI) studies, as it facilitates accurate determination of the crystal plane normal with respect to the incident beam direction and thus allows control the electron channeling conditions. Unfortunately commercial SACP modes developed in the past were limited in spatial resolution and are often no longer offered. In this contribution we present a novel approach for collecting high resolution SACPs (HR-SACPs) developed on a Gemini column. This HR-SACP technique combines the first demonstrated sub-micron spatial resolution with high angular accuracy of about 0.1°, at a convenient working distance of 10mm. This innovative approach integrates the use of aperture alignment coils to rock the beam with a digitally calibrated beam shift procedure to ensure the rocking beam is maintained on a point of interest. Moreover a new methodology to accurately measure SACP spatial resolution is proposed. While column considerations limit the rocking angle to 4°, this range is adequate to index the HR-SACP in conjunction with the pattern simulated from the approximate orientation deduced by EBSD. This new technique facilitates Accurate ECCI (A-ECCI) studies from very fine grained and/or highly strained materials. It offers also new insights for developing HR-SACP modes on new generation high-resolution electron columns. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Use of Electronic Resources in a Private University in Nigeria ...

    African Journals Online (AJOL)

    The study examined awareness and constraints in the use of electronic resources by lecturers and students of Ajayi Crowther University, Oyo, Nigeria. It aimed at justifying the resources expended in the provision of electronic resources in terms of awareness, patronage and factors that may be affecting awareness and use ...

  16. Gender Analysis Of Electronic Information Resource Use: The Case ...

    African Journals Online (AJOL)

    Based on the findings the study concluded that access and use of electronic information resources creates a “social digital divide” along gender lines. The study ... Finally, the library needs to change its marketing strategies on the availability of electronic information resources to increase awareness of these resources.

  17. Electronic Resource Management System. Vernetzung von Lizenzinformationen

    Directory of Open Access Journals (Sweden)

    Michaela Selbach

    2014-12-01

    Full Text Available In den letzten zehn Jahren spielen elektronische Ressourcen im Bereich der Erwerbung eine zunehmend wichtige Rolle: Eindeutig lässt sich hier ein Wandel in den Bibliotheken (fort vom reinen Printbestand zu immer größeren E-Only-Beständen feststellen. Die stetig wachsende Menge an E-Ressourcen und deren Heterogenität stellt Bibliotheken vor die Herausforderung, die E-Ressourcen effizient zu verwalten. Nicht nur Bibliotheken, sondern auch verhandlungsführende Institutionen von Konsortial- und Allianzlizenzen benötigen ein geeignetes Instrument zur Verwaltung von Lizenzinformationen, welches den komplexen Anforderungen moderner E-Ressourcen gerecht wird. Die Deutsche Forschungsgemeinschaft (DFG unterstützt ein Projekt des Hochschulbibliothekszentrums des Landes Nordrhein-Westfalen (hbz, der Universitätsbibliothek Freiburg, der Verbundzentrale des Gemeinsamen Bibliotheksverbundes (GBV und der Universitätsbibliothek Frankfurt, in dem ein bundesweit verfügbares Electronic Ressource Managementsystem (ERMS aufgebaut werden soll. Ein solches ERMS soll auf Basis einer zentralen Knowledge Base eine einheitliche Nutzung von Daten zur Lizenzverwaltung elektronischer Ressourcen auf lokaler, regionaler und nationaler Ebene ermöglichen. Statistische Auswertungen, Rechteverwaltung für alle angeschlossenen Bibliotheken, kooperative Datenpflege sowie ein über standardisierte Schnittstellen geführter Datenaustausch stehen bei der Erarbeitung der Anforderungen ebenso im Fokus wie die Entwicklung eines Daten- und Funktionsmodells. In the last few years the importance of electronic resources in library acquisitions has increased significantly. There has been a shift from mere print holdings to both e- and print combinations and even e-only subscriptions. This shift poses a double challenge for libraries: On the one hand they have to provide their e-resource collections to library users in an appealing way, on the other hand they have to manage these

  18. Electronic human resource management: Enhancing or entrancing?

    Directory of Open Access Journals (Sweden)

    Paul Poisat

    2017-07-01

    Full Text Available Orientation: This article provides an investigation into the current level of development of the body of knowledge related to electronic human resource management (e-HRM by means of a qualitative content analysis. Several aspects of e-HRM, namely definitions of e-HRM, the theoretical perspectives around e-HRM, the role of e-HRM, the various types of e-HRM and the requirements for successful e-HRM, are examined. Research purpose: The purpose of the article was to determine the status of e-HRM and examine the studies that report on the link between e-HRM and organisational productivity. Motivation for the study: e-HRM has the capacity to improve organisational efficiency and leverage the role of human resources (HR as a strategic business partner. Main findings: The notion that the implementation of e-HRM will lead to improved organisational productivity is commonly assumed; however, empirical evidence in this regard was found to be limited. Practical/managerial implications: From the results of this investigation it is evident that more research is required to gain a greater understanding of the influence of e-HRM on organisational productivity, as well as to develop measures for assessing this influence. Contribution: This article proposes additional areas to research and measure when investigating the effectiveness of e-HRM. It provides a different lens from which to view e-HRM assessment whilst keeping it within recognised HR measurement parameters (the HR value chain. In addition, it not only provides areas for measuring e-HRM’s influence but also provides important clues as to how the measurements may be approached.

  19. Utilization of electronic information resources by academic staff at ...

    African Journals Online (AJOL)

    The study investigated the utilization of Electronic Information resources by the academic staff of Makerere University in Uganda. It examined the academic staff awareness of the resources available, the types of resources provided by the Makerere University Library, the factors affecting resource utilization. The study was ...

  20. 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 ...

  1. Human enamel structure studied by high resolution electron microscopy

    International Nuclear Information System (INIS)

    Wen, S.L.

    1989-01-01

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

  2. On the resolution of the electron microscopic radioautography

    International Nuclear Information System (INIS)

    Uchida, Kazuko; Daimon, Tateo; Kawai, Kazuhiro

    1981-01-01

    The aim of electron microscopic radioautography is to reveal the exact localization of certain substances at the macromolecular level. In order to attain this object the establishment of a fine grain development method is indispensable. Some of latent images are formed at the contact surface between the polyhedral halide silver grain and the section surface, where the impact of #betta# particles come directly from the section involved, and since it is in contact with the section it remains in place even after development and gelatin removal. This latent image finally becomes a developed silver grain in the electron microscope radioautogram. Although the limit of resolution in electron microscopic radioautography is supposed to be the diameter of halide silver grains in emulsion, it may be improved by considering the fact that the contact area between the halide silver grain and the section surface is the minimum unit of resolution. The minimum resolution of electron microscopic radioautography was determined histologically to be about 100A. (author)

  3. Users satisfaction with electronic information resources and services ...

    African Journals Online (AJOL)

    This study investigated users satisfaction on the use of electronic information resources and services in MTN Net libraries in ABU & UNIBEN. Two objectives and one null hypotheses were formulated and tested with respect to the users' satisfaction on electronic information resources and services in MTN Net libraries in ...

  4. The Role of the Acquisitions Librarian in Electronic Resources Management

    Science.gov (United States)

    Pomerantz, Sarah B.

    2010-01-01

    With the ongoing shift to electronic formats for library resources, acquisitions librarians, like the rest of the profession, must adapt to the rapidly changing landscape of electronic resources by keeping up with trends and mastering new skills related to digital publishing, technology, and licensing. The author sought to know what roles…

  5. Optical circular deflector with attosecond resolution for ultrashort electron beam

    Directory of Open Access Journals (Sweden)

    Zhen Zhang

    2017-05-01

    Full Text Available A novel method using high-power laser as a circular deflector is proposed for the measurement of femtosecond (fs and sub-fs electron beam. In the scheme, the electron beam interacts with a laser pulse operating in a radially polarized doughnut mode (TEM_{01^{*}} in a helical undulator, generating angular kicks along the beam in two directions at the same time. The phase difference between the two angular kicks makes the beam form a ring after a propagation section with appropriate phase advance, which can reveal the current profile of the electron beam. Detailed theoretical analysis of the method and numerical results with reasonable parameters are both presented. It is shown that the temporal resolution can reach up to ∼100 attosecond, which is a significant improvement for the diagnostics of ultrashort electron beam.

  6. Construction of a high resolution electron beam profile monitor

    International Nuclear Information System (INIS)

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

    1993-01-01

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

  7. Precipitate resolution in an electron irradiated ni-si alloy

    Science.gov (United States)

    Watanabe, H.; Muroga, T.; Yoshida, N.; Kitajima, K.

    1988-09-01

    Precipitate resolution processes in a Ni-12.6 at% Si alloy under electron irradiation have been observed by means of HVEM. Above 400°C, growth and resolution of Ni 3Si precipitates were observed simultaneously. The detail stereoscopic observation showed that the precipitates close to free surfaces grew, while those in the middle of a specimen dissolved. The critical dose when the precipitates start to shrink increases with increasing the depth. This depth dependence of the precipitate behavior under irradiation has a close relation with the formation of surface precipitates and the growth of solute depleted zone beneath them. The temperature and dose dependence of the resolution rate showed that the precipitates in the solute depleted zone dissolved by the interface controlled process of radiation-enhanced diffusion.

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

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  9. Averaging scheme for atomic resolution off-axis electron holograms.

    Science.gov (United States)

    Niermann, T; Lehmann, M

    2014-08-01

    All micrographs are limited by shot-noise, which is intrinsic to the detection process of electrons. For beam insensitive specimen this limitation can in principle easily be circumvented by prolonged exposure times. However, in the high-resolution regime several instrumental instabilities limit the applicable exposure time. Particularly in the case of off-axis holography the holograms are highly sensitive to the position and voltage of the electron-optical biprism. We present a novel reconstruction algorithm to average series of off-axis holograms while compensating for specimen drift, biprism drift, drift of biprism voltage, and drift of defocus, which all might cause problematic changes from exposure to exposure. We show an application of the algorithm utilizing also the possibilities of double biprism holography, which results in a high quality exit-wave reconstruction with 75 pm resolution at a very high signal-to-noise ratio. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2016-08-01

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

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

    International Nuclear Information System (INIS)

    Tanaka, H.; Huebner, R.H.

    1976-01-01

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

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

    International Nuclear Information System (INIS)

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

    1990-01-01

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

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

    OpenAIRE

    Boyes, Edward; Gai, Pratibha

    2017-01-01

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

  14. 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.

  15. 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.

  16. Selection and Evaluation of Electronic Resources

    Directory of Open Access Journals (Sweden)

    Doğan Atılgan

    2013-11-01

    Full Text Available Publication boom and issues related to controlling and accession of printed sources have created some problems after World War II. Consequently, publishing industry has encountered the problem of finding possible solution for emerged situation. Industry of electronic publishing has started to improve with the rapid increase of the price of printed sources as well as the problem of publication boom. The first effects of electronic publishing were appeared on the academic and scholarly publications then electronic publishing became a crucial part of all types of publications. As a result of these developments, collection developments and service policies of information centers were also significantly changed. In this article, after a general introduction about selection and evaluation processes of electronic publications, the subscribed databases by a state and a privately owned university in Turkey and their usage were examined.

  17. Prospects of linear reconstruction in atomic resolution electron holographic tomography

    International Nuclear Information System (INIS)

    Krehl, Jonas; Lubk, Axel

    2015-01-01

    Tomography commonly requires a linear relation between the measured signal and the underlying specimen property; for Electron Holographic Tomography this is given by the Phase Grating Approximation (PGA). While largely valid at medium resolution, discrepancies arise at high resolution imaging conditions. We set out to investigate the artefacts that are produced if the reconstruction still assumes the PGA even with an atomic resolution tilt series. To forego experimental difficulties the holographic tilt series was simulated. The reconstructed electric potential clearly shows peaks at the positions of the atoms. These peaks have characterisitic deformations, which can be traced back to the defocus a particular atom has in the holograms of the tilt series. Exchanging an atom for one of a different atomic number results in a significant change in the reconstructed potential that is well contained within the atom's peak. - Highlights: • We simulate a holographic tilt series of a nanocrystal with atomic resolution. • Using PGA-based Holographic Tomography we reconstruct the atomic structure. • The reconstruction shows characteristic artefacts, chiefly caused by defocus. • Changing one atom's Z produces a well localised in the reconstruction

  18. Prospects of linear reconstruction in atomic resolution electron holographic tomography

    Energy Technology Data Exchange (ETDEWEB)

    Krehl, Jonas, E-mail: Jonas.Krehl@triebenberg.de; Lubk, Axel

    2015-03-15

    Tomography commonly requires a linear relation between the measured signal and the underlying specimen property; for Electron Holographic Tomography this is given by the Phase Grating Approximation (PGA). While largely valid at medium resolution, discrepancies arise at high resolution imaging conditions. We set out to investigate the artefacts that are produced if the reconstruction still assumes the PGA even with an atomic resolution tilt series. To forego experimental difficulties the holographic tilt series was simulated. The reconstructed electric potential clearly shows peaks at the positions of the atoms. These peaks have characterisitic deformations, which can be traced back to the defocus a particular atom has in the holograms of the tilt series. Exchanging an atom for one of a different atomic number results in a significant change in the reconstructed potential that is well contained within the atom's peak. - Highlights: • We simulate a holographic tilt series of a nanocrystal with atomic resolution. • Using PGA-based Holographic Tomography we reconstruct the atomic structure. • The reconstruction shows characteristic artefacts, chiefly caused by defocus. • Changing one atom's Z produces a well localised in the reconstruction.

  19. Improving Electronic Resources through Holistic Budgeting

    Science.gov (United States)

    Kusik, James P.; Vargas, Mark A.

    2009-01-01

    To establish a more direct link between its collections and the educational goals of Saint Xavier University, the Byrne Memorial Library has adopted a "holistic" approach to collection development. This article examines how traditional budget practices influenced the library's selection of resources and describes how holistic collection…

  20. High-resolution electron microscopy and its applications.

    Science.gov (United States)

    Li, F H

    1987-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Ma Siqi

    2011-01-01

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

  2. Single-shot 35 fs temporal resolution electron shadowgraphy

    Energy Technology Data Exchange (ETDEWEB)

    Scoby, C. M.; Li, R. K.; Threlkeld, E.; To, H.; Musumeci, P. [Department of Physics and Astronomy, UCLA, Los Angeles, California 90095 (United States)

    2013-01-14

    We obtain single-shot time-resolved shadowgraph images of the electromagnetic fields resulting from the interaction of a high intensity ultrashort laser pulse with a metal surface. Using a high brightness relativistic electron beam and a high streaking speed radiofrequency deflector, we report <35 fs temporal resolution enabling a direct visualization of the retarded-time dominated field evolution which follows the laser-induced charge emission. A model including the finite signal propagation speed well reproduces the data and yields measurements of fundamental parameters in short pulse laser-matter interaction such as the amount of emitted charge and the emission time scale.

  3. Single-shot 35 fs temporal resolution electron shadowgraphy

    International Nuclear Information System (INIS)

    Scoby, C. M.; Li, R. K.; Threlkeld, E.; To, H.; Musumeci, P.

    2013-01-01

    We obtain single-shot time-resolved shadowgraph images of the electromagnetic fields resulting from the interaction of a high intensity ultrashort laser pulse with a metal surface. Using a high brightness relativistic electron beam and a high streaking speed radiofrequency deflector, we report <35 fs temporal resolution enabling a direct visualization of the retarded-time dominated field evolution which follows the laser-induced charge emission. A model including the finite signal propagation speed well reproduces the data and yields measurements of fundamental parameters in short pulse laser-matter interaction such as the amount of emitted charge and the emission time scale.

  4. Page 170 Use of Electronic Resources by Undergraduates in Two ...

    African Journals Online (AJOL)

    undergraduate students use electronic resources such as NUC virtual library, HINARI, ... web pages articles from magazines, encyclopedias, pamphlets and other .... of Nigerian university libraries have Internet connectivity, some of the system.

  5. Secondary electron spectroscopy and Auger microscopy at high spatial resolution. Application to scanning electron microscopy

    International Nuclear Information System (INIS)

    Le Gressus, Claude; Massignon, Daniel; Sopizet, Rene

    1979-01-01

    Secondary electron spectroscopy (SES), Auger electron spectroscopy (AES) and electron energy loss spectroscopy (ELS) are combined with ultra high vacuum scanning microscopy (SEM) for surface analysis at high spatial resolution. Reliability tests for the optical column for the vacuum and for the spectrometer are discussed. Furthermore the sensitivity threshold in AES which is compatible with a non destructive surface analysis at high spatial resolution is evaluated. This combination of all spectroscopies is used in the study of the beam damage correlated with the well known secondary electron image (SEI) darkening still observed in ultra high vacuum. The darkening is explained as a bulk decontamination of the sample rather than as a surface contamination from the residual vacuum gas [fr

  6. Millisecond resolution electron fluxes from the Cluster satellites: Calibrated EDI ambient electron data

    Science.gov (United States)

    Förster, Matthias; Rashev, Mikhail; Haaland, Stein

    2017-04-01

    The Electron Drift Instrument (EDI) onboard Cluster can measure 500 eV and 1 keV electron fluxes with high time resolution during passive operation phases in its Ambient Electron (AE) mode. Data from this mode is available in the Cluster Science Archive since October 2004 with a cadence of 16 Hz in the normal mode or 128 Hz for burst mode telemetry intervals. The fluxes are recorded at pitch angles of 0, 90, and 180 degrees. This paper describes the calibration and validation of these measurements. The high resolution AE data allow precise temporal and spatial diagnostics of magnetospheric boundaries and will be used for case studies and statistical studies of low energy electron fluxes in the near-Earth space. We show examples of applications.

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

    International Nuclear Information System (INIS)

    Krakow, W.; Shaw, T.M.

    1988-01-01

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

  8. High resolution electron attachment to molecules of atmospheric relevance

    International Nuclear Information System (INIS)

    Senn, G.

    2000-10-01

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

  9. Utilisation of Electronic Information Resources By Lecturers in ...

    African Journals Online (AJOL)

    This study assesses the use of information resources, specifically, electronic databases by lecturers/teachers in Universities and Colleges of Education in South Western Nigeria. Information resources are central to teachers' education. It provides lecturers/teachers access to information that enhances research and ...

  10. Preservation and conservation of electronic information resources of ...

    African Journals Online (AJOL)

    The major holdings of the broadcast libraries of the Nigerian Television Authority (NTA) are electronic information resources; therefore, providing safe places for general management of these resources have aroused interest in the industry in Nigeria for sometimes. The need to study the preservation and conservation of ...

  11. Using XML Technologies to Organize Electronic Reference Resources

    OpenAIRE

    Huser, Vojtech; Del Fiol, Guilherme; Rocha, Roberto A.

    2005-01-01

    Provision of access to reference electronic resources to clinicians is becoming increasingly important. We have created a framework for librarians to manage access to these resources at an enterprise level, rather than at the individual hospital libraries. We describe initial project requirements, implementation details, and some preliminary results.

  12. Euler European Libraries and Electronic Resources in Mathematical Sciences

    CERN Document Server

    The Euler Project. Karlsruhe

    The European Libraries and Electronic Resources (EULER) Project in Mathematical Sciences provides the EulerService site for searching out "mathematical resources such as books, pre-prints, web-pages, abstracts, proceedings, serials, technical reports preprints) and NetLab (for Internet resources), this outstanding engine is capable of simple, full, and refined searches. It also offers a browse option, which responds to entries in the author, keyword, and title fields. Further information about the Project is provided at the EULER homepage.

  13. Building an electronic resource collection a practical guide

    CERN Document Server

    Lee, Stuart D

    2004-01-01

    This practical book guides information professionals step-by-step through building and managing an electronic resource collection. It outlines the range of electronic products currently available in abstracting and indexing, bibliographic, and other services and then describes how to effectively select, evaluate and purchase them.

  14. Organizational matters of competition in electronic educational resources

    Directory of Open Access Journals (Sweden)

    Ирина Карловна Войтович

    2015-12-01

    Full Text Available The article examines the experience of the Udmurt State University in conducting competitions of educational publications and electronic resources. The purpose of such competitions is to provide methodological support to educational process. The main focus is on competition of electronic educational resources. The technology of such contests is discussed through detailed analysis of the main stages of the contest. It is noted that the main task of the preparatory stage of the competition is related to the development of regulations on competition and the definition of criteria for selection of the submitted works. The paper also proposes a system of evaluation criteria of electronic educational resources developed by members of the contest organizing committee and jury members. The article emphasizes the importance of not only the preparatory stages of the competition, but also measures for its completion, aimed at training teachers create quality e-learning resources.

  15. Measuring the electron bunch timing with femtosecond resolution at FLASH

    International Nuclear Information System (INIS)

    Bock, Marie Kristin

    2013-03-01

    Bunch arrival time monitors (BAMs) are an integral part of the laser-based synchronisation system which is being developed at the Free Electron Laser in Hamburg (FLASH).The operation principle comprises the measurement of the electron bunch arrival time relative to the optical timing reference, which is provided by actively length-stabilised fibre-links of the synchronisation system. The monitors are foreseen to be used as a standard diagnostic tool, not only for FLASH but also for the future European X-Ray Free-Electron Laser (European XFEL). The present bunch arrival time monitors have evolved from proof-of-principle experiments to beneficial diagnostic devices, which are almost permanently available during standard machine operation. This achievement has been a major objective of this thesis. The developments went in parallel to improvements in the reliable and low-maintenance operation of the optical synchronisation system. The key topics of this thesis comprised the characterisation and optimisation of the opto-mechanical front-ends of both, the fibre-links and the BAMs. The extent of applications involving the bunch arrival time information has been enlarged, providing automated measurements for properties of the RF acceleration modules, for instance, the RF on-crest phase determination and the measurement of energy fluctuations. Furthermore, two of the currently installed BAMs are implemented in an active phase and gradient stabilisation of specific modules in order to minimise the arrival time jitter of the electron bunches at the location of the FEL undulators, which is crucial for a high timing resolution of pump-probe experiments.

  16. Measuring the electron bunch timing with femtosecond resolution at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Bock, Marie Kristin

    2013-03-15

    Bunch arrival time monitors (BAMs) are an integral part of the laser-based synchronisation system which is being developed at the Free Electron Laser in Hamburg (FLASH).The operation principle comprises the measurement of the electron bunch arrival time relative to the optical timing reference, which is provided by actively length-stabilised fibre-links of the synchronisation system. The monitors are foreseen to be used as a standard diagnostic tool, not only for FLASH but also for the future European X-Ray Free-Electron Laser (European XFEL). The present bunch arrival time monitors have evolved from proof-of-principle experiments to beneficial diagnostic devices, which are almost permanently available during standard machine operation. This achievement has been a major objective of this thesis. The developments went in parallel to improvements in the reliable and low-maintenance operation of the optical synchronisation system. The key topics of this thesis comprised the characterisation and optimisation of the opto-mechanical front-ends of both, the fibre-links and the BAMs. The extent of applications involving the bunch arrival time information has been enlarged, providing automated measurements for properties of the RF acceleration modules, for instance, the RF on-crest phase determination and the measurement of energy fluctuations. Furthermore, two of the currently installed BAMs are implemented in an active phase and gradient stabilisation of specific modules in order to minimise the arrival time jitter of the electron bunches at the location of the FEL undulators, which is crucial for a high timing resolution of pump-probe experiments.

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

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  18. Why and How to Measure the Use of Electronic Resources

    Directory of Open Access Journals (Sweden)

    Jean Bernon

    2008-11-01

    Full Text Available A complete overview of library activity implies a complete and reliable measurement of the use of both electronic resources and printed materials. This measurement is based on three sets of definitions: document types, use types and user types. There is a common model of definitions for printed materials, but a lot of questions and technical issues remain for electronic resources. In 2006 a French national working group studied these questions. It relied on the COUNTER standard, but found it insufficient and pointed out the need for local tools such as web markers and deep analysis of proxy logs. Within the French national consortium COUPERIN, a new working group is testing ERMS, SUSHI standards, Shibboleth authentication, along with COUNTER standards, to improve the counting of the electronic resources use. At this stage this counting is insufficient and its improvement will be a European challenge for the future.

  19. 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

  20. Access to electronic resources by visually impaired people

    Directory of Open Access Journals (Sweden)

    Jenny Craven

    2003-01-01

    Full Text Available Research into access to electronic resources by visually impaired people undertaken by the Centre for Research in Library and Information Management has not only explored the accessibility of websites and levels of awareness in providing websites that adhere to design for all principles, but has sought to enhance understanding of information seeking behaviour of blind and visually impaired people when using digital resources.

  1. Practical guide to electronic resources in the humanities

    CERN Document Server

    Dubnjakovic, Ana

    2010-01-01

    From full-text article databases to digitized collections of primary source materials, newly emerging electronic resources have radically impacted how research in the humanities is conducted and discovered. This book, covering high-quality, up-to-date electronic resources for the humanities, is an easy-to-use annotated guide for the librarian, student, and scholar alike. It covers online databases, indexes, archives, and many other critical tools in key humanities disciplines including philosophy, religion, languages and literature, and performing and visual arts. Succinct overviews of key eme

  2. Accelerator-based Single-shot Ultrafast Transmission Electron Microscope with Picosecond Temporal Resolution and Nanometer Spatial Resolution

    OpenAIRE

    Xiang, D.; Fu, F.; Zhang, J.; Huang, X.; Wang, L.; Wang, X.; Wan, W.

    2014-01-01

    We present feasibility study of an accelerator-based ultrafast transmission electron microscope (u-TEM) capable of producing a full field image in a single-shot with simultaneous picosecond temporal resolution and nanometer spatial resolution. We study key physics related to performance of u-TEMs, and discuss major challenges as well as possible solutions for practical realization of u-TEMs. The feasibility of u-TEMs is confirmed through simulations using realistic electron beam parameters. W...

  3. Discipline, availability of electronic resources and the use of Finnish National Electronic Library - FinELib

    Directory of Open Access Journals (Sweden)

    Sanna Torma

    2004-01-01

    Full Text Available This study elaborated relations between digital library use by university faculty, users' discipline and the availability of key resources in the Finnish National Electronic Library (FinELib, Finnish national digital library, by using nationwide representative survey data. The results show that the perceived availability of key electronic resources by researchers in FinELib was a stronger predictor of the frequency and purpose of use of its services than users' discipline. Regardless of discipline a good perceived provision of central resources led to a more frequent use of FinELib. The satisfaction with the services did not vary with the discipline, but with the perceived availability of resources.

  4. The Electron Microscopy Outreach Program: A Web-based resource for research and education.

    Science.gov (United States)

    Sosinsky, G E; Baker, T S; Hand, G; Ellisman, M H

    1999-01-01

    We have developed a centralized World Wide Web (WWW)-based environment that serves as a resource of software tools and expertise for biological electron microscopy. A major focus is molecular electron microscopy, but the site also includes information and links on structural biology at all levels of resolution. This site serves to help integrate or link structural biology techniques in accordance with user needs. The WWW site, called the Electron Microscopy (EM) Outreach Program (URL: http://emoutreach.sdsc.edu), provides scientists with computational and educational tools for their research and edification. In particular, we have set up a centralized resource containing course notes, references, and links to image analysis and three-dimensional reconstruction software for investigators wanting to learn about EM techniques either within or outside of their fields of expertise. Copyright 1999 Academic Press.

  5. APES: Acute Precipitating Electron Spectrometer - A High Time Resolution Monodirectional Magnetic Deflection Electron Spectrometer

    Science.gov (United States)

    Michell, R. G.; Samara, M.; Grubbs, G., II; Ogasawara, K.; Miller, G.; Trevino, J. A.; Webster, J.; Stange, J.

    2016-01-01

    We present a description of the Acute Precipitating Electron Spectrometer (APES) that was designed and built for the Ground-to-Rocket Electron Electrodynamics Correlative Experiment (GREECE) auroral sounding rocket mission. The purpose was to measure the precipitating electron spectrum with high time resolution, on the order of milliseconds. The trade-off made in order to achieve high time resolution was to limit the aperture to only one look direction. The energy selection was done by using a permanent magnet to separate the incoming electrons, such that the different energies would fall onto different regions of the microchannel plate and therefore be detected by different anodes. A rectangular microchannel plate (MCP) was used (15 mm x 100 mm), and there was a total of 50 discrete anodes under the MCP, each one 15 mm x 1.5 mm, with a 0.5 mm spacing between anodes. The target energy range of APES was 200 eV to 30 keV.

  6. Accelerator-based single-shot ultrafast transmission electron microscope with picosecond temporal resolution and nanometer spatial resolution

    Science.gov (United States)

    Xiang, D.; Fu, F.; Zhang, J.; Huang, X.; Wang, L.; Wang, X.; Wan, W.

    2014-09-01

    We present feasibility study of an accelerator-based ultrafast transmission electron microscope (u-TEM) capable of producing a full field image in a single-shot with simultaneous picosecond temporal resolution and nanometer spatial resolution. We study key physics related to performance of u-TEMs and discuss major challenges as well as possible solutions for practical realization of u-TEMs. The feasibility of u-TEMs is confirmed through simulations using realistic electron beam parameters. We anticipate that u-TEMs with a product of temporal and spatial resolution beyond 10-19 ms will open up new opportunities in probing matter at ultrafast temporal and ultrasmall spatial scales.

  7. Access to electronic information resources by students of federal ...

    African Journals Online (AJOL)

    The paper discusses access to electronic information resources by students of Federal Colleges of Education in Eha-Amufu and Umunze. Descriptive survey design was used to investigate sample of 526 students. Sampling technique used was a Multi sampling technique. Data for the study were generated using ...

  8. Electronic Commerce Resource Centers. An Industry--University Partnership.

    Science.gov (United States)

    Gulledge, Thomas R.; Sommer, Rainer; Tarimcilar, M. Murat

    1999-01-01

    Electronic Commerce Resource Centers focus on transferring emerging technologies to small businesses through university/industry partnerships. Successful implementation hinges on a strategic operating plan, creation of measurable value for customers, investment in customer-targeted training, and measurement of performance outputs. (SK)

  9. ANALYTICAL REVIEW OF ELECTRONIC RESOURCES FOR THE STUDY OF LATIN

    Directory of Open Access Journals (Sweden)

    Olena Yu. Balalaieva

    2014-04-01

    Full Text Available The article investigates the current state of development of e-learning content in the Latin language. It is noted that the introduction of ICT in the educational space has expanded the possibility of studying Latin, opened access to digital libraries resources, made it possible to use scientific and educational potential and teaching Latin best practices of world's leading universities. A review of foreign and Ukrainian information resources and electronic editions for the study of Latin is given. Much attention was paid to the didactic potential of local and online multimedia courses of Latin, electronic textbooks, workbooks of interactive tests and exercises, various dictionaries and software translators, databases and digital libraries. Based on analysis of the world market of educational services and products the main trends in the development of information resources and electronic books are examined. It was found that multimedia courses with interactive exercises or workbooks with interactive tests, online dictionaries and translators are the most widely represented and demanded. The noticeable lagging of Ukrainian education and computer linguistics in quantitative and qualitative measures in this industry is established. The obvious drawback of existing Ukrainian resources and electronic editions for the study of Latin is their noninteractive nature. The prospects of e-learning content in Latin in Ukraine are outlined.

  10. Adoption and use of electronic information resources by medical ...

    African Journals Online (AJOL)

    This study investigated the adoption and use of electronic information resources by medical science students of the University of Benin. The descriptive survey research design was adopted for the study and 390 students provided the data. Data collected were analysed with descriptive Statistics(Simple percentage and ...

  11. Modern ICT Tools: Online Electronic Resources Sharing Using Web ...

    African Journals Online (AJOL)

    Modern ICT Tools: Online Electronic Resources Sharing Using Web 2.0 and Its Implications For Library And Information Practice In Nigeria. ... The PDF file you selected should load here if your Web browser has a PDF reader plug-in installed (for example, a recent version of Adobe Acrobat Reader). If you would like more ...

  12. Technical Communicator: A New Model for the Electronic Resources Librarian?

    Science.gov (United States)

    Hulseberg, Anna

    2016-01-01

    This article explores whether technical communicator is a useful model for electronic resources (ER) librarians. The fields of ER librarianship and technical communication (TC) originated and continue to develop in relation to evolving technologies. A review of the literature reveals four common themes for ER librarianship and TC. While the…

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

    CERN Multimedia

    Gizon, A; Putaux, J

    2002-01-01

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

  14. A high resolution global wind atlas - improving estimation of world wind resources

    DEFF Research Database (Denmark)

    Badger, Jake; Ejsing Jørgensen, Hans

    2011-01-01

    to population centres, electrical transmission grids, terrain types, and protected land areas are important parts of the resource assessment downstream of the generation of wind climate statistics. Related to these issues of integration are the temporal characteristics and spatial correlation of the wind...... resources. These aspects will also be addressed by the Global Wind Atlas. The Global Wind Atlas, through a transparent methodology, will provide a unified, high resolution, and public domain dataset of wind energy resources for the whole world. The wind atlas data will be the most appropriate wind resource...

  15. 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

  16. MODEL OF AN ELECTRONIC EDUCATIONAL RESOURCE OF NEW GENERATION

    Directory of Open Access Journals (Sweden)

    Anatoliy V. Loban

    2016-01-01

    Full Text Available The mathematical structure of the modular architecture of an electronic educational resource (EER of new generation, which allows to decompose the process of studying the subjects of the course at a hierarchically ordered set of data (knowledge and procedures for manipulating them, to determine the roles of participants of process of training of and technology the development and use of EOR in the study procrate.

  17. Actors and networks in resource conflict resolution under climate change in rural Kenya

    Science.gov (United States)

    Ngaruiya, Grace W.; Scheffran, Jürgen

    2016-05-01

    The change from consensual decision-making arrangements into centralized hierarchical chieftaincy schemes through colonization disrupted many rural conflict resolution mechanisms in Africa. In addition, climate change impacts on land use have introduced additional socio-ecological factors that complicate rural conflict dynamics. Despite the current urgent need for conflict-sensitive adaptation, resolution efficiency of these fused rural institutions has hardly been documented. In this context, we analyse the Loitoktok network for implemented resource conflict resolution structures and identify potential actors to guide conflict-sensitive adaptation. This is based on social network data and processes that are collected using the saturation sampling technique to analyse mechanisms of brokerage. We find that there are three different forms of fused conflict resolution arrangements that integrate traditional institutions and private investors in the community. To effectively implement conflict-sensitive adaptation, we recommend the extension officers, the council of elders, local chiefs and private investors as potential conduits of knowledge in rural areas. In conclusion, efficiency of these fused conflict resolution institutions is aided by the presence of holistic resource management policies and diversification in conflict resolution actors and networks.

  18. Practical considerations for high spatial and temporal resolution dynamic transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, Michael R. [Materials Science and Technology Division, Chemistry and Materials Science Directorate, Lawrence Livermore National Laboratory, P.O. Box 808, L-356, Livermore, CA 94550 (United States)], E-mail: armstrong30@llnl.gov; Boyden, Ken [Materials Science and Technology Division, Chemistry and Materials Science Directorate, Lawrence Livermore National Laboratory, P.O. Box 808, L-356, Livermore, CA 94550 (United States); Browning, Nigel D. [Materials Science and Technology Division, Chemistry and Materials Science Directorate, Lawrence Livermore National Laboratory, P.O. Box 808, L-356, Livermore, CA 94550 (United States); Department of Chemical Engineering and Materials Science, University of California-Davis, One Shields Avenue, Davis, CA 95616 (United States); Campbell, Geoffrey H.; Colvin, Jeffrey D.; De Hope, William J.; Frank, Alan M. [Materials Science and Technology Division, Chemistry and Materials Science Directorate, Lawrence Livermore National Laboratory, P.O. Box 808, L-356, Livermore, CA 94550 (United States); Gibson, David J.; Hartemann, Fred [N Division, Physics and Advanced Technologies Directorate, Lawrence Livermore National Laboratory, P.O. Box 808, L-280, Livermore, CA 94550 (United States); Kim, Judy S. [Materials Science and Technology Division, Chemistry and Materials Science Directorate, Lawrence Livermore National Laboratory, P.O. Box 808, L-356, Livermore, CA 94550 (United States); Department of Chemical Engineering and Materials Science, University of California-Davis, One Shields Avenue, Davis, CA 95616 (United States); King, Wayne E.; La Grange, Thomas B.; Pyke, Ben J.; Reed, Bryan W.; Shuttlesworth, Richard M.; Stuart, Brent C.; Torralva, Ben R. [Materials Science and Technology Division, Chemistry and Materials Science Directorate, Lawrence Livermore National Laboratory, P.O. Box 808, L-356, Livermore, CA 94550 (United States)

    2007-04-15

    Although recent years have seen significant advances in the spatial resolution possible in the transmission electron microscope (TEM), the temporal resolution of most microscopes is limited to video rate at best. This lack of temporal resolution means that our understanding of dynamic processes in materials is extremely limited. High temporal resolution in the TEM can be achieved, however, by replacing the normal thermionic or field emission source with a photoemission source. In this case the temporal resolution is limited only by the ability to create a short pulse of photoexcited electrons in the source, and this can be as short as a few femtoseconds. The operation of the photo-emission source and the control of the subsequent pulse of electrons (containing as many as 5x10{sup 7} electrons) create significant challenges for a standard microscope column that is designed to operate with a single electron in the column at any one time. In this paper, the generation and control of electron pulses in the TEM to obtain a temporal resolution <10{sup -6} s will be described and the effect of the pulse duration and current density on the spatial resolution of the instrument will be examined. The potential of these levels of temporal and spatial resolution for the study of dynamic materials processes will also be discussed.

  19. Practical considerations for high spatial and temporal resolution dynamic transmission electron microscopy

    International Nuclear Information System (INIS)

    Armstrong, Michael R.; Boyden, Ken; Browning, Nigel D.; Campbell, Geoffrey H.; Colvin, Jeffrey D.; De Hope, William J.; Frank, Alan M.; Gibson, David J.; Hartemann, Fred; Kim, Judy S.; King, Wayne E.; La Grange, Thomas B.; Pyke, Ben J.; Reed, Bryan W.; Shuttlesworth, Richard M.; Stuart, Brent C.; Torralva, Ben R.

    2007-01-01

    Although recent years have seen significant advances in the spatial resolution possible in the transmission electron microscope (TEM), the temporal resolution of most microscopes is limited to video rate at best. This lack of temporal resolution means that our understanding of dynamic processes in materials is extremely limited. High temporal resolution in the TEM can be achieved, however, by replacing the normal thermionic or field emission source with a photoemission source. In this case the temporal resolution is limited only by the ability to create a short pulse of photoexcited electrons in the source, and this can be as short as a few femtoseconds. The operation of the photo-emission source and the control of the subsequent pulse of electrons (containing as many as 5x10 7 electrons) create significant challenges for a standard microscope column that is designed to operate with a single electron in the column at any one time. In this paper, the generation and control of electron pulses in the TEM to obtain a temporal resolution -6 s will be described and the effect of the pulse duration and current density on the spatial resolution of the instrument will be examined. The potential of these levels of temporal and spatial resolution for the study of dynamic materials processes will also be discussed

  20. Non-Proportionality of Electron Response and Energy Resolution of Compton Electrons in Scintillators

    Science.gov (United States)

    Swiderski, L.; Marcinkowski, R.; Szawlowski, M.; Moszynski, M.; Czarnacki, W.; Syntfeld-Kazuch, A.; Szczesniak, T.; Pausch, G.; Plettner, C.; Roemer, K.

    2012-02-01

    Non-proportionality of light yield and energy resolution of Compton electrons in three scintillators (LaBr3:Ce, LYSO:Ce and CsI:Tl) were studied in a wide energy range from 10 keV up to 1 MeV. The experimental setup was comprised of a High Purity Germanium detector and tested scintillators coupled to a photomultiplier. Probing the non-proportionality and energy resolution curves at different energies was obtained by changing the position of various radioactive sources with respect to both detectors. The distance between both detectors and source was kept small to make use of Wide Angle Compton Coincidence (WACC) technique, which allowed us to scan large range of scattering angles simultaneously and obtain relatively high coincidence rate of 100 cps using weak sources of about 10 μCi activity. The results are compared with those obtained by direct irradiation of the tested scintillators with gamma-ray sources and fitting the full-energy peaks.

  1. End-of-life resource recovery from emerging electronic products

    DEFF Research Database (Denmark)

    Parajuly, Keshav; Habib, Komal; Cimpan, Ciprian

    2016-01-01

    Integrating product design with appropriate end-of-life (EoL) processing is widely recognized to have huge potentials in improving resource recovery from electronic products. In this study, we investigate both the product characteristics and EoL processing of robotic vacuum cleaner (RVC), as a case...... of emerging electronic product, in order to understand the recovery fate of different materials and its linkage to product design. Ten different brands of RVC were dismantled and their material composition and design profiles were studied. Another 125 RVCs (349 kg) were used for an experimental trial...... at a conventional ‘shred-and-separate’ type preprocessing plant in Denmark. A detailed material flow analysis was performed throughout the recycling chain. The results show a mismatch between product design and EoL processing, and the lack of practical implementation of ‘Design for EoL’ thinking. In the best...

  2. Analysis of Human Resources Management Strategy in China Electronic Commerce Enterprises

    Science.gov (United States)

    Shao, Fang

    The paper discussed electronic-commerce's influence on enterprise human resources management, proposed and proved the human resources management strategy which electronic commerce enterprise should adopt from recruitment strategy to training strategy, keeping talent strategy and other ways.

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

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... We have made continuum radio observations of these HII regions of the W51 complex at 240, 610, 1060 and 1400 MHz using GMRT with lower resolution (20'' × 15'') at the lowest frequency. The observed spectra of the prominent thermal subcomponents of W51 have been fitted to a free-free emission ...

  4. Toward single electron resolution phonon mediated ionization detectors

    Energy Technology Data Exchange (ETDEWEB)

    Mirabolfathi, Nader, E-mail: mirabolfathi@physics.tamu.edu [Department of Physics and Astronomy, Texas A& M University (United States); Harris, H. Rusty; Mahapatra, Rupak; Sundqvist, Kyle; Jastram, Andrew [Department of Physics and Astronomy, Texas A& M University (United States); Serfass, Bruno; Faiez, Dana; Sadoulet, Bernard [Department of Physics, University of California at Berkeley (United States)

    2017-05-21

    Experiments seeking to detect rare event interactions such as dark matter or coherent elastic neutrino nucleus scattering are striving for large mass detectors with very low detection threshold. Using Neganov-Luke phonon amplification effect, the Cryogenic Dark Matter Search (CDMS) experiment is reaching unprecedented RMS resolutions of ∼14 eV{sub ee}. CDMSlite is currently the most sensitive experiment to WIMPs of mass ∼5 GeV/c{sup 2} but is limited in achieving higher phonon gains due to an early onset of leakage current into Ge crystals. The contact interface geometry is particularly weak for blocking hole injection from the metal, and thus a new design is demonstrated that allows high voltage bias via vacuum separated electrode. With an increased bias voltage and a×2 Luke phonon gain, world best RMS resolution of sigma ∼7 eV{sub ee} for 0.25 kg (d=75 mm, h=1 cm) Ge detectors was achieved. Since the leakage current is a function of the field and the phonon gain is a function of the applied voltage, appropriately robust interface blocking material combined with thicker substrate (25 mm) will reach a resolution of ∼2.8 eV{sub ee}. In order to achieve better resolution of ∼ eV, we are investigating a layer of insulator between the phonon readout surface and the semiconductor crystals.

  5. High-resolution modeling assessment of tidal stream resource in Western Passage of Maine, USA

    Science.gov (United States)

    Yang, Zhaoqing; Wang, Taiping; Feng, Xi; Xue, Huijie; Kilcher, Levi

    2017-04-01

    Although significant efforts have been taken to assess the maximum potential of tidal stream energy at system-wide scale, accurate assessment of tidal stream energy resource at project design scale requires detailed hydrodynamic simulations using high-resolution three-dimensional (3-D) numerical models. Extended model validation against high quality measured data is essential to minimize the uncertainties of the resource assessment. Western Passage in the State of Maine in U.S. has been identified as one of the top ranking sites for tidal stream energy development in U.S. coastal waters, based on a number of criteria including tidal power density, market value and transmission distance. This study presents an on-going modeling effort for simulating the tidal hydrodynamics in Western Passage using the 3-D unstructured-grid Finite Volume Community Ocean Model (FVCOM). The model domain covers a large region including the entire the Bay of Fundy with grid resolution varies from 20 m in the Western Passage to approximately 1000 m along the open boundary near the mouth of Bay of Fundy. Preliminary model validation was conducted using existing NOAA measurements within the model domain. Spatial distributions of tidal power density were calculated and extractable tidal energy was estimated using a tidal turbine module embedded in FVCOM under different tidal farm scenarios. Additional field measurements to characterize resource and support model validation were discussed. This study provides an example of high resolution resource assessment based on the guidance recommended by the International Electrotechnical Commission Technical Specification.

  6. On the optimum resolution of transmission-electron backscattered diffraction (t-EBSD)

    Energy Technology Data Exchange (ETDEWEB)

    Bremen, R. van; Ribas Gomes, D.; Jeer, L.T.H. de; Ocelík, V., E-mail: v.ocelik@rug.nl; De Hosson, J.Th.M.

    2016-01-15

    The work presented aims at determining the optimum physical resolution of the transmission-electron backscattered diffraction (t-EBSD) technique. The resolution depends critically on intrinsic factors such as the density, atomic number and thickness of the specimen but also on the extrinsic experimental set-up of the electron beam voltage, specimen tilt and detector position. In the present study, the so-called physical resolution of a typical t-EBSD set-up was determined with the use of Monte Carlo simulations and confronted to experimental findings. In the case of a thin Au film of 20 nm, the best resolution obtained was 9 nm whereas for a 100 nm Au film the best resolution was 66 nm. The precise dependence of resolution on thickness was found to vary differently depending on the specific elements involved. This means that the resolution of each specimen should be determined individually. Experimentally the median probe size of the t-EBSD for a 140 nm thick AuAg specimen was measured to be 87 nm. The first and third quartiles of the probe size measurements were found to be 60 nm and 118 nm. Simulation of this specimen resulted in a resolution of 94 nm which fits between these quartiles. - Highlights: • Intrinsic and extrinsic factors affecting resolution of t-EBSD are determined and characterized. • Distinction between resolutions of transmitted and detected electrons is determined. • The simulated results are confirmed experimentally on 140 nm thick AuAg foil.

  7. COLLABORATIVE (PARTNERSHIP AS A FORM OF "RESTORATIVE JUSTICE" IN CONFLICT RESOLUTION FOREST RESOURCES MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Agus Surono

    2017-02-01

    Full Text Available Conflict management of forest resources among communities around forest areas often occur in various regions, particularly in some national parks and forest management as Perhutani in Java and Inhutani outside Java. These conflicts indicate the forest resources management has not effectively made a positive impact in improving communities welfare around forest areas. Although the provisions of Article 3 in conjunction with Article 68 of Law No. 41 of 1999 on Forestry, provide the basis for communities around the forest rights of forest areas, but in reality there are still people around forest areas that do not enjoy such rights and it is this which often leads to conflicts in the management of forest resources. In the event of conflict, the solution can be done collaboratively (partnership which is one form of restorative justice is an alternative dispute resolution (ADR. Keywords: collaborative, conflict, restorative justice, forest resources.

  8. Effects of Electronic Information Resources Skills Training for Lecturers on Pedagogical Practices and Research Productivity

    Science.gov (United States)

    Bhukuvhani, Crispen; Chiparausha, Blessing; Zuvalinyenga, Dorcas

    2012-01-01

    Lecturers use various electronic resources at different frequencies. The university library's information literacy skills workshops and seminars are the main sources of knowledge of accessing electronic resources. The use of electronic resources can be said to have positively affected lecturers' pedagogical practices and their work in general. The…

  9. Electronic Resources and Mission Creep: Reorganizing the Library for the Twenty-First Century

    Science.gov (United States)

    Stachokas, George

    2009-01-01

    The position of electronic resources librarian was created to serve as a specialist in the negotiation of license agreements for electronic resources, but mission creep has added more functions to the routine work of electronic resources such as cataloging, gathering information for collection development, and technical support. As electronic…

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

    International Nuclear Information System (INIS)

    Kilaas, R.

    1985-03-01

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

  11. Graphene-enabled electron microscopy and correlated super-resolution microscopy of wet cells.

    Science.gov (United States)

    Wojcik, Michal; Hauser, Margaret; Li, Wan; Moon, Seonah; Xu, Ke

    2015-06-11

    The application of electron microscopy to hydrated biological samples has been limited by high-vacuum operating conditions. Traditional methods utilize harsh and laborious sample dehydration procedures, often leading to structural artefacts and creating difficulties for correlating results with high-resolution fluorescence microscopy. Here, we utilize graphene, a single-atom-thick carbon meshwork, as the thinnest possible impermeable and conductive membrane to protect animal cells from vacuum, thus enabling high-resolution electron microscopy of wet and untreated whole cells with exceptional ease. Our approach further allows for facile correlative super-resolution and electron microscopy of wet cells directly on the culturing substrate. In particular, individual cytoskeletal actin filaments are resolved in hydrated samples through electron microscopy and well correlated with super-resolution results.

  12. Electronic Document Management: A Human Resource Management Case Study

    Directory of Open Access Journals (Sweden)

    Thomas Groenewald

    2004-11-01

    Full Text Available This case study serve as exemplar regarding what can go wrong with the implementation of an electronic document management system. Knowledge agility and knowledge as capital, is outlined against the backdrop of the information society and knowledge economy. The importance of electronic document management and control is sketched thereafter. The literature review is concluded with the impact of human resource management on knowledge agility, which includes references to the learning organisation and complexity theory. The intervention methodology, comprising three phases, follows next. The results of the three phases are presented thereafter. Partial success has been achieved with improving the human efficacy of electronic document management, however the client opted to discontinue the system in use. Opsomming Die gevalle studie dien as voorbeeld van wat kan verkeerd loop met die implementering van ’n elektroniese dokumentbestuur sisteem. Teen die agtergrond van die inligtingsgemeenskap en kennishuishouding word kennissoepelheid en kennis as kapitaal bespreek. Die literatuurstudie word afgesluit met die inpak van menslikehulpbronbestuur op kennissoepelheid, wat ook die verwysings na die leerorganisasie en kompleksietydsteorie insluit. Die metodologie van die intervensie, wat uit drie fases bestaan, volg daarna. Die resultate van die drie fases word vervolgens aangebied. Slegs gedeelte welslae is behaal met die verbetering van die menslike doeltreffendheid ten opsigte van elektroniese dokumentbestuur. Die klient besluit egter om nie voort te gaan om die huidige sisteem te gebruik nie.

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  14. Simulations of the temporal and spatial resolution for a compact time-resolved electron diffractometer

    Science.gov (United States)

    Robinson, Matthew S.; Lane, Paul D.; Wann, Derek A.

    2016-02-01

    A novel compact electron gun for use in time-resolved gas electron diffraction experiments has recently been designed and commissioned. In this paper we present and discuss the extensive simulations that were performed to underpin the design in terms of the spatial and temporal qualities of the pulsed electron beam created by the ionisation of a gold photocathode using a femtosecond laser. The response of the electron pulses to a solenoid lens used to focus the electron beam has also been studied. The simulated results show that focussing the electron beam affects the overall spatial and temporal resolution of the experiment in a variety of ways, and that factors that improve the resolution of one parameter can often have a negative effect on the other. A balance must, therefore, be achieved between spatial and temporal resolution. The optimal experimental time resolution for the apparatus is predicted to be 416 fs for studies of gas-phase species, while the predicted spatial resolution of better than 2 nm-1 compares well with traditional time-averaged electron diffraction set-ups.

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

    International Nuclear Information System (INIS)

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

    1987-01-01

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

  16. Analogical reasoning in working memory: resources shared among relational integration, interference resolution, and maintenance.

    Science.gov (United States)

    Cho, Soohyun; Holyoak, Keith J; Cannon, Tyrone D

    2007-09-01

    We report a series of experiments using a pictorial analogy task designed to manipulate relational integration, interference resolution, and active maintenance simultaneously. The difficulty of the problems was varied in terms of the number of relations to be integrated, the need for interference resolution, and the duration of maintenance required to correctly solve the analogy. The participants showed decreases in performance when integrating multiple relations, as compared with a single relation, and when interference resolution was required in solving the analogy. When the participants were required to integrate multiple relations while simultaneously engaged in interference resolution, performance was worse, as compared with problems that incorporated either of these features alone. Maintenance of information across delays in the range of 1-4.5 sec led to greater decrements in visual memory, as compared with analogical reasoning. Misleading information caused interference when it had been necessarily attended to and maintained in working memory and, hence, had to be actively suppressed. However, sources of conflict within information that had not been attended to or encoded into working memory did not interfere with the ongoing controlled information processing required for relational integration. The findings provide evidence that relational integration and interference resolution depend on shared cognitive resources in working memory during analogical reasoning.

  17. Minimum detection limit and spatial resolution of thin-sample field-emission electron probe microanalysis

    International Nuclear Information System (INIS)

    Kubo, Yugo; Hamada, Kotaro; Urano, Akira

    2013-01-01

    The minimum detection limit and spatial resolution for a thinned semiconductor sample were determined by electron probe microanalysis (EPMA) using a Schottky field emission (FE) electron gun and wavelength dispersive X-ray spectrometry. Comparison of the FE-EPMA results with those obtained using energy dispersive X-ray spectrometry in conjunction with scanning transmission electron microscopy, confirmed that FE-EPMA is largely superior in terms of detection sensitivity. Thin-sample FE-EPMA is demonstrated as a very effective method for high resolution, high sensitivity analysis in a laboratory environment because a high probe current and high signal-to-noise ratio can be achieved. - Highlights: • Minimum detection limit and spatial resolution determined for FE-EPMA. • Detection sensitivity of FE-EPMA greatly superior to that of STEM-EDX. • Minimum detection limit and spatial resolution controllable by probe current

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

    NARCIS (Netherlands)

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

    2006-01-01

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

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

    NARCIS (Netherlands)

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

    1996-01-01

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

  20. A Simple Metric for Determining Resolution in Optical, Ion, and Electron Microscope Images.

    Science.gov (United States)

    Curtin, Alexandra E; Skinner, Ryan; Sanders, Aric W

    2015-06-01

    A resolution metric intended for resolution analysis of arbitrary spatially calibrated images is presented. By fitting a simple sigmoidal function to pixel intensities across slices of an image taken perpendicular to light-dark edges, the mean distance over which the light-dark transition occurs can be determined. A fixed multiple of this characteristic distance is then reported as the image resolution. The prefactor is determined by analysis of scanning transmission electron microscope high-angle annular dark field images of Si. This metric has been applied to optical, scanning electron microscope, and helium ion microscope images. This method provides quantitative feedback about image resolution, independent of the tool on which the data were collected. In addition, our analysis provides a nonarbitrary and self-consistent framework that any end user can utilize to evaluate the resolution of multiple microscopes from any vendor using the same metric.

  1. High-resolution electron microscopy of detonation nanodiamond

    International Nuclear Information System (INIS)

    Iakoubovskii, K; Mitsuishi, K; Furuya, K

    2008-01-01

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

  2. High-resolution electron microscopy of detonation nanodiamond

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-04-16

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

  3. State of the art in atomic resolution off-axis electron holography

    International Nuclear Information System (INIS)

    Linck, Martin; Freitag, Bert; Kujawa, Stephan; Lehmann, Michael; Niermann, Tore

    2012-01-01

    As proposed by Hannes Lichte, to resolve structure–property relations not only the question “Which atom is where?” but also the question “Which fields are around?” has to be answered. High-resolution off-axis electron holography opens up an access to these key questions in that it allows accessing the complete exit-wave of the object provided within the information limit of the microscope, i.e. amplitude and phase including atomic details such as position and species, and moreover, information about large area electric potentials and magnetic fields, which a conventional transmission electron microscope is blind for—also when using a Cs-corrector. For an excellent object exit-wave reconstruction, special care has to be taken on the hologram quality, i.e. interference fringe contrast and electron dose. Severe restrictions are given to signal resolution by the limited brightness of the electron source. Utilizing a new high-brightness Schottky field electron emitter in a state-of-the-art transmission electron microscope operated at 300 kV, the phase signal resolution at atomic resolution can significantly be enhanced. An improvement by at least a factor of 2.88 compared to the most recently reported single hologram at atomic resolution is found. To proof the applicability of this setup to real materials science problems, a grain boundary of gold has been investigated holographically. -- Highlights: ► Impact of the brightness on the reconstructed signal in electron holography. ► Factor 2.8 gain in signal quality by setup with a high brightness electron gun. ► Investigation of a grain boundary in gold with a state-of-the-art holography setup. ► A-posteriori aberration fine-tuning for true one Angstrom resolution in the object wave. ► Mistilt analysis on the atomic scale by numerical wave optics.

  4. Study of spatial resolution of coordinate detectors based on Gas Electron Multipliers

    Science.gov (United States)

    Kudryavtsev, V. N.; Maltsev, T. V.; Shekhtman, L. I.

    2017-02-01

    Spatial resolution of GEM-based tracking detectors is determined in the simulation and measured in the experiments. The simulation includes GEANT4 implemented transport of high energy electrons with careful accounting of atomic relaxation processes including emission of fluorescent photons and Auger electrons and custom post-processing with accounting of diffusion, gas amplification fluctuations, distribution of signals on readout electrodes, electronics noise and particular algorithm of final coordinate calculation (center of gravity). The simulation demonstrates that the minimum of spatial resolution of about 10 μm can be achieved with a gas mixture of Ar -CO2 (75-25 %) at a strips pitch from 250 μm to 300 μm. At a larger pitch the resolution quickly degrades reaching 80-100 μm at a pitch of 460-500 μm. Spatial resolution of low-material triple-GEM detectors for the DEUTERON facility at the VEPP-3 storage ring is measured at the extracted beam facility of the VEPP-4 M collider. One-coordinate resolution of the DEUTERON detector is measured with electron beam of 500 MeV, 1 GeV and 3.5 GeV energies. The determined value of spatial resolution varies in the range from approximately 35 μm to 50 μm for orthogonal tracks in the experiments.

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

    International Nuclear Information System (INIS)

    Houben, L.; Bar Sadan, M.

    2011-01-01

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

  6. Imaging modes for potential mapping in semiconductor devices by electron holography with improved lateral resolution

    Energy Technology Data Exchange (ETDEWEB)

    Sickmann, Jan, E-mail: jan.sickmann@triebenberg.de [Triebenberg Laboratory, Institute of Structure Physics, Technische Universitaet Dresden, 01069 Dresden (Germany); Formanek, Petr; Linck, Martin [Triebenberg Laboratory, Institute of Structure Physics, Technische Universitaet Dresden, 01069 Dresden (Germany); Muehle, Uwe [Institut fuer Werkstoffwissenschaft, Technische Universitaet Bergakademie Freiberg, 09599 Freiberg (Germany); Lichte, Hannes [Triebenberg Laboratory, Institute of Structure Physics, Technische Universitaet Dresden, 01069 Dresden (Germany)

    2011-03-15

    Electron holography is the highest resolving tool for dopant profiling at nanometre-scale resolution. In order to measure the object areas of interest in a hologram, both a wide field of view and a sufficient lateral resolution are required. The usual path of rays for recording holograms with an electron biprism using the standard objective lens does not meet these requirements, because the field of view amounts to some 10 nm only, however, at a resolution of 0.1 nm better than needed here. Therefore, instead of the standard objective lens, the Lorentz lens is widely used for holography of semiconductors, since it provides a field of view up to 1000 nm at a sufficient lateral resolution of about 10 nm. Since the size of semiconductor structures is steadily shrinking, there is now a need for better lateral resolution at an appropriate field of view. Therefore, additional paths of rays for recording holograms are studied with special emphasis on the parameters field of view and lateral resolution. The findings allow an optimized scheme with a field of view of 200 nm and a lateral resolution of 3.3 nm filling the gap between the existing set-ups. In addition, the Lorentz lens is no longer required for investigation of non-magnetic materials, since the new paths of rays are realized with the standard objective lens and diffraction lens. An example proves the applicability of this arrangement for future semiconductor technology. -- Research highlights: {yields} Imaging modes for potential mapping in semiconductor devices by electron holography. {yields} Using objective and diffraction lens for imaging instead of Lorentz lens. {yields} Detailed investigation of four different paths of rays and its basic parameters for holographic application: field of view, lateral resolution, signal resolution. {yields} Measuring the phase profile of a field effect transistor with 3 nm lateral resolution at field of view of 200 nm.

  7. Ultrashort and coherent single-electron pulses for diffraction at ultimate resolutions

    International Nuclear Information System (INIS)

    Kirchner, Friedrich Oscar

    2013-01-01

    Ultrafast electron diffraction is a powerful tool for studying structural dynamics with femtosecond temporal and sub-aangstroem spatial resolutions. It benefits from the high scattering cross-sections of electrons compared X-rays and allows the examination of thin samples, surfaces and gases. One of the main challenges in ultrafast electron diffraction is the generation of electron pulses with a short duration and a large transverse coherence. The former limits the temporal resolution of the experiment while the latter determines the maximum size of the scattering structures that can be studied. In this work, we strive to push the limits of electron diffraction towards higher temporal and spatial resolutions. The decisive step in our approach is to eliminate all detrimental effects caused by Coulomb repulsion between the electrons by reducing the number of electrons per pulse to one. In this situation, the electrons' longitudinal and transverse velocity distributions are determined solely by the photoemission process. By reducing the electron source size on the photocathode, we make use of the small transverse velocity spread to produce electron pulses with a transverse coherence length of 20 nm, which is about an order of magnitude larger than the reported values for comparable experiments. The energy distribution of an ensemble of single-electron pulses from a photoemission source is directly linked to the mismatch between the photon energy and the cathode's work function. This excess energy can be reduced by using a photon energy close to the material's work function. Using a tunable source of ultraviolet pulses, we demonstrate the reduction of the velocity spread of the electrons, resulting in a shorter duration of the electron pulses. The reduced electron pulse durations achieved by a tunable excitation or by other approaches require new characterization techniques for electron pulses. We developed a novel method for the characterization of electron pulses at

  8. Design and performance of a spin-polarized electron energy loss spectrometer with high momentum resolution

    Energy Technology Data Exchange (ETDEWEB)

    Vasilyev, D.; Kirschner, J. [Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany)

    2016-08-15

    We describe a new “complete” spin-polarized electron energy loss spectrometer comprising a spin-polarized primary electron source, an imaging electron analyzer, and a spin analyzer of the “spin-polarizing mirror” type. Unlike previous instruments, we have a high momentum resolution of less than 0.04 Å{sup −1}, at an energy resolution of 90-130 meV. Unlike all previous studies which reported rather broad featureless data in both energy and angle dependence, we find richly structured spectra depending sensitively on small changes of the primary energy, the kinetic energy after scattering, and of the angle of incidence. The key factor is the momentum resolution.

  9. Electron energy-loss spectrometry at the frontier of spatial and energy resolution

    International Nuclear Information System (INIS)

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

    2004-01-01

    Full text: Electron energy-loss spectroscopy (EELS) in the transmission electron microscope (TEM) is now used routinely as a means of measuring chemical and structural properties of very small regions of a thin specimen. The power of this technique depends significantly on two parameters: its spatial resolution and the energy resolution available in the spectrum and in the energy-filtered TEM (EFTEM) image. The cold field emission source and the Schottky emitter have made an energy resolution below 1 eV possible and it is now feasible to obtain data with a spatial resolution close to atomic dimensions, given the right instrumentation and specimen. EFTEM allows to record elemental maps at sub-nanometre resolution, being mainly limited by chromatic and spherical aberration of the objective lens and by delocalization of inelastic scattering. Recently the possibility of correcting spherical and even chromatic aberrations of electron lenses has become a practical reality thus improving the point resolution of the TEM to below 0.1 nm. The other limiting factor for EFTEM resolution is delocalization. However, recent measurements show that resolution values in the range of 1 nm and below can be achieved, even for energy-losses of only a few eV. In terms of energy-resolution, EELS and EFTEM compare less favourably with other spectroscopies. For common TEMs, the overall energy-resolution is mainly determined by the energy width of the electron source, typically between 0.5 and 1.5 eV. For comparison, synchrotron x-ray sources and beam line spectrometers, provide a resolution well below 0.1 eV for absorption spectroscopy. During the early sixties, the energy spread of an electron beam could be reduced by incorporating an energy-filter into the illumination system, but the system lacked spatial resolution. Later developments combined high energy resolution in the range of 0.1 eV with improved spatial resolution. Recently, FEI introduced a new high resolution EELS system based

  10. Electronic Safety Resource Tools -- Supporting Hydrogen and Fuel Cell Commercialization

    Energy Technology Data Exchange (ETDEWEB)

    Barilo, Nick F.

    2014-09-29

    The Pacific Northwest National Laboratory (PNNL) Hydrogen Safety Program conducted a planning session in Los Angeles, CA on April 1, 2014 to consider what electronic safety tools would benefit the next phase of hydrogen and fuel cell commercialization. A diverse, 20-person team led by an experienced facilitator considered the question as it applied to the eight most relevant user groups. The results and subsequent evaluation activities revealed several possible resource tools that could greatly benefit users. The tool identified as having the greatest potential for impact is a hydrogen safety portal, which can be the central location for integrating and disseminating safety information (including most of the tools identified in this report). Such a tool can provide credible and reliable information from a trustworthy source. Other impactful tools identified include a codes and standards wizard to guide users through a series of questions relating to application and specific features of the requirements; a scenario-based virtual reality training for first responders; peer networking tools to bring users from focused groups together to discuss and collaborate on hydrogen safety issues; and a focused tool for training inspectors. Table ES.1 provides results of the planning session, including proposed new tools and changes to existing tools.

  11. An economic prediction of the finer resolution level wavelet coefficients in electronic structure calculations.

    Science.gov (United States)

    Nagy, Szilvia; Pipek, János

    2015-12-21

    In wavelet based electronic structure calculations, introducing a new, finer resolution level is usually an expensive task, this is why often a two-level approximation is used with very fine starting resolution level. This process results in large matrices to calculate with and a large number of coefficients to be stored. In our previous work we have developed an adaptively refined solution scheme that determines the indices, where the refined basis functions are to be included, and later a method for predicting the next, finer resolution coefficients in a very economic way. In the present contribution, we would like to determine whether the method can be applied for predicting not only the first, but also the other, higher resolution level coefficients. Also the energy expectation values of the predicted wave functions are studied, as well as the scaling behaviour of the coefficients in the fine resolution limit.

  12. Energy Resolution of the CMS ECAL Barrel Super-Module Using MGPA Electronics

    CERN Document Server

    Dewhirst, G

    2004-01-01

    A method for extracting the amplitude of a pulse has been developed in order to optimise the energy resolution of a CMS ECAL super-module in the 2003 test beam. The method consists of using a set of weights to extract the amplitude as well as subtract the baseline level event by event. For an incident beam impact restricted to an area of 4times 4~mm^2 the resolution of the ECAL, which uses the final prototype version of the MGPA electronics, is shown to match the target resolution.

  13. Controlling user access to electronic resources without password

    Science.gov (United States)

    Smith, Fred Hewitt

    2015-06-16

    Described herein are devices and techniques for remotely controlling user access to a restricted computer resource. The process includes pre-determining an association of the restricted computer resource and computer-resource-proximal environmental information. Indicia of user-proximal environmental information are received from a user requesting access to the restricted computer resource. Received indicia of user-proximal environmental information are compared to associated computer-resource-proximal environmental information. User access to the restricted computer resource is selectively granted responsive to a favorable comparison in which the user-proximal environmental information is sufficiently similar to the computer-resource proximal environmental information. In at least some embodiments, the process further includes comparing user-supplied biometric measure and comparing it with a predetermined association of at least one biometric measure of an authorized user. Access to the restricted computer resource is granted in response to a favorable comparison.

  14. Instrumentation at the National Center for Electron Microscopy: the Atomic Resolution Microscope

    International Nuclear Information System (INIS)

    Gronsky, R.; Thomas, G.

    1983-01-01

    The Atomic Resolution Microscope (ARM) is one of two unique high voltage electron microscopes at the Lawrence Berkeley Laboratory's National Center for Electron Microscopy (NCEM). The latest results from this new instrument which was manufactured by JEOL, Ltd. to the performance specifications of the NCEM, delivered in January of 1983, and soon to be open to access by the entire microscopy community are given. Details of its history and development are given and its performance specifications are reviewed

  15. Longitudinal profile diagnostic scheme with subfemtosecond resolution for high-brightness electron beams

    Directory of Open Access Journals (Sweden)

    G. Andonian

    2011-07-01

    Full Text Available High-resolution measurement of the longitudinal profile of a relativistic electron beam is of utmost importance for linac based free-electron lasers and other advanced accelerator facilities that employ ultrashort bunches. In this paper, we investigate a novel scheme to measure ultrashort bunches (subpicosecond with exceptional temporal resolution (hundreds of attoseconds and dynamic range. The scheme employs two orthogonally oriented deflecting sections. The first imparts a short-wavelength (fast temporal resolution horizontal angular modulation on the beam, while the second imparts a long-wavelength (slow angular kick in the vertical dimension. Both modulations are observable on a standard downstream screen in the form of a streaked sinusoidal beam structure. We demonstrate, using scaled variables in a quasi-1D approximation, an expression for the temporal resolution of the scheme and apply it to a proof-of-concept experiment at the UCLA Neptune high-brightness injector facility. The scheme is also investigated for application at the SLAC NLCTA facility, where we show that the subfemtosecond resolution is sufficient to resolve the temporal structure of the beam used in the echo-enabled free-electron laser. We employ beam simulations to verify the effect for typical Neptune and NLCTA parameter sets and demonstrate the feasibility of the concept.

  16. The Internet School of Medicine: use of electronic resources by medical trainees and the reliability of those resources.

    Science.gov (United States)

    Egle, Jonathan P; Smeenge, David M; Kassem, Kamal M; Mittal, Vijay K

    2015-01-01

    Electronic sources of medical information are plentiful, and numerous studies have demonstrated the use of the Internet by patients and the variable reliability of these sources. Studies have investigated neither the use of web-based resources by residents, nor the reliability of the information available on these websites. A web-based survey was distributed to surgical residents in Michigan and third- and fourth-year medical students at an American allopathic and osteopathic medical school and a Caribbean allopathic school regarding their preferred sources of medical information in various situations. A set of 254 queries simulating those faced by medical trainees on rounds, on a written examination, or during patient care was developed. The top 5 electronic resources cited by the trainees were evaluated for their ability to answer these questions accurately, using standard textbooks as the point of reference. The respondents reported a wide variety of overall preferred resources. Most of the 73 responding medical trainees favored textbooks or board review books for prolonged studying, but electronic resources are frequently used for quick studying, clinical decision-making questions, and medication queries. The most commonly used electronic resources were UpToDate, Google, Medscape, Wikipedia, and Epocrates. UpToDate and Epocrates had the highest percentage of correct answers (47%) and Wikipedia had the lowest (26%). Epocrates also had the highest percentage of wrong answers (30%), whereas Google had the lowest percentage (18%). All resources had a significant number of questions that they were unable to answer. Though hardcopy books have not been completely replaced by electronic resources, more than half of medical students and nearly half of residents prefer web-based sources of information. For quick questions and studying, both groups prefer Internet sources. However, the most commonly used electronic resources fail to answer clinical queries more than half

  17. Rapid increase of near atomic resolution virus capsid structures determined by cryo-electron microscopy.

    Science.gov (United States)

    Ho, Phuong T; Reddy, Vijay S

    2018-01-01

    The recent technological advances in electron microscopes, detectors, as well as image processing and reconstruction software have brought single particle cryo-electron microscopy (cryo-EM) into prominence for determining structures of bio-molecules at near atomic resolution. This has been particularly true for virus capsids, ribosomes, and other large assemblies, which have been the ideal specimens for structural studies by cryo-EM approaches. An analysis of time series metadata of virus structures on the methods of structure determination, resolution of the structures, and size of the virus particles revealed a rapid increase in the virus structures determined by cryo-EM at near atomic resolution since 2010. In addition, the data highlight the median resolution (∼3.0 Å) and size (∼310.0 Å in diameter) of the virus particles determined by X-ray crystallography while no such limits exist for cryo-EM structures, which have a median diameter of 508 Å. Notably, cryo-EM virus structures in the last four years have a median resolution of 3.9 Å. Taken together with minimal sample requirements, not needing diffraction quality crystals, and being able to achieve similar resolutions of the crystal structures makes cryo-EM the method of choice for current and future virus capsid structure determinations. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. High spatial resolution upgrade of the electron cyclotron emission radiometer for the DIII-D tokamak.

    Science.gov (United States)

    Truong, D D; Austin, M E

    2014-11-01

    The 40-channel DIII-D electron cyclotron emission (ECE) radiometer provides measurements of Te(r,t) at the tokamak midplane from optically thick, second harmonic X-mode emission over a frequency range of 83-130 GHz. The frequency spacing of the radiometer's channels results in a spatial resolution of ∼1-3 cm, depending on local magnetic field and electron temperature. A new high resolution subsystem has been added to the DIII-D ECE radiometer to make sub-centimeter (0.6-0.8 cm) resolution Te measurements. The high resolution subsystem branches off from the regular channels' IF bands and consists of a microwave switch to toggle between IF bands, a switched filter bank for frequency selectivity, an adjustable local oscillator and mixer for further frequency down-conversion, and a set of eight microwave filters in the 2-4 GHz range. Higher spatial resolution is achieved through the use of a narrower (200 MHz) filter bandwidth and closer spacing between the filters' center frequencies (250 MHz). This configuration allows for full coverage of the 83-130 GHz frequency range in 2 GHz bands. Depending on the local magnetic field, this translates into a "zoomed-in" analysis of a ∼2-4 cm radial region. Expected uses of these channels include mapping the spatial dependence of Alfven eigenmodes, geodesic acoustic modes, and externally applied magnetic perturbations. Initial Te measurements, which demonstrate that the desired resolution is achieved, are presented.

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

    Science.gov (United States)

    Houben, L; Bar Sadan, M

    2011-01-01

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

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

    NARCIS (Netherlands)

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

    2006-01-01

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

  1. Study of position resolution and electron-hadron separation of electromagnetic calorimeter with a silicon structure

    International Nuclear Information System (INIS)

    Gorodnichev, V.B.; Kachanov, V.A.; Khodyrev, V.Yu.; Kurchaninov, L.L.; Rykali, V.V.; Solovianov, V.L.; Ukhalov, M.N.

    1993-01-01

    The maximum shower silicon strip detectors embedded in a module of sandwich-type electromagnetic calorimeter have been tested. The position resolution at different depths of the silicon structure has been measured. The results on electron-hadron separation obtained as a byproduct in this study are presented, and possibility of their improvement is discussed. 8 refs., 10 figs., 1 tab

  2. Atomic resolution electrostatic potential mapping of graphene sheets by off-axis electron holography

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, David, E-mail: david.cooper@cea.fr [University Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054, Grenoble (France); Pan, Cheng-Ta; Haigh, Sarah [School of Materials, The University of Manchester, Manchester M13 9PL (United Kingdom)

    2014-06-21

    Off-axis electron holography has been performed at atomic resolution with the microscope operated at 80 kV to provide electrostatic potential maps from single, double, and triple layer graphene. These electron holograms have been reconstructed in order to obtain information about atomically resolved and mean inner potentials. We propose that off-axis electron holography can now be used to measure the electrical properties in a range of two-dimensional semiconductor materials and three dimensional devices comprising stacked layers of films to provide important information about their electrical properties.

  3. Atomic resolution electrostatic potential mapping of graphene sheets by off-axis electron holography

    International Nuclear Information System (INIS)

    Cooper, David; Pan, Cheng-Ta; Haigh, Sarah

    2014-01-01

    Off-axis electron holography has been performed at atomic resolution with the microscope operated at 80 kV to provide electrostatic potential maps from single, double, and triple layer graphene. These electron holograms have been reconstructed in order to obtain information about atomically resolved and mean inner potentials. We propose that off-axis electron holography can now be used to measure the electrical properties in a range of two-dimensional semiconductor materials and three dimensional devices comprising stacked layers of films to provide important information about their electrical properties.

  4. Developing Humanities Collections in the Digital Age: Exploring Humanities Faculty Engagement with Electronic and Print Resources

    Science.gov (United States)

    Kachaluba, Sarah Buck; Brady, Jessica Evans; Critten, Jessica

    2014-01-01

    This article is based on quantitative and qualitative research examining humanities scholars' understandings of the advantages and disadvantages of print versus electronic information resources. It explores how humanities' faculty members at Florida State University (FSU) use print and electronic resources, as well as how they perceive these…

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

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  6. Electronic resource management practical perspectives in a new technical services model

    CERN Document Server

    Elguindi, Anne

    2012-01-01

    A significant shift is taking place in libraries, with the purchase of e-resources accounting for the bulk of materials spending. Electronic Resource Management makes the case that technical services workflows need to make a corresponding shift toward e-centric models and highlights the increasing variety of e-formats that are forcing new developments in the field.Six chapters cover key topics, including: technical services models, both past and emerging; staffing and workflow in electronic resource management; implementation and transformation of electronic resource management systems; the ro

  7. A design for a subminiature, low energy scanning electron microscope with atomic resolution

    International Nuclear Information System (INIS)

    Eastham, D. A.; Edmondson, P.; Greene, S.; Donnelly, S.; Olsson, E.; Svensson, K.; Bleloch, A.

    2009-01-01

    We describe a type of scanning electron microscope that works by directly imaging the electron field-emission sites on a nanotip. Electrons are extracted from the nanotip through a nanoscale aperture, accelerated in a high electric field, and focused to a spot using a microscale Einzel lens. If the whole microscope (accelerating section and lens) and the focal length are both restricted in size to below 10 μm, then computer simulations show that the effects of aberration are extremely small and it is possible to have a system with approximately unit magnification at electron energies as low as 300 eV. Thus a typical emission site of 1 nm diameter will produce an image of the same size, and an atomic emission site will give a resolution of 0.1-0.2 nm (1-2 A). Also, because the beam is not allowed to expand beyond 100 nm in diameter, the depth of field is large and the contribution to the beam spot size from chromatic aberrations is less than 0.02 nm (0.2 A) for 500 eV electrons. Since it is now entirely possible to make stable atomic sized emitters (nanopyramids), it is expected that this instrument will have atomic resolution. Furthermore the brightness of the beam is determined only by the field emission and can be up to 1x10 6 times larger than in a typical (high energy) electron microscope. The advantages of this low energy, bright-beam electron microscope with atomic resolution are described and include the possibility of it being used to rapidly sequence the human genome from a single strand of DNA as well as being able to identify atomic species directly from the elastic scattering of electrons

  8. Electronic resources access and usage among the postgraduates of ...

    African Journals Online (AJOL)

    ... and usage among the postgraduates of a Nigerian University of Technology. ... faced by postgraduates in using e-resources include takes too much time to find, ... Resources, Access, Use, Postgraduat, Students, University, Technology, Nigeria ... By Country · List All Titles · Free To Read Titles This Journal is Open Access.

  9. Strategic Planning for Electronic Resources Management: A Case Study at Gustavus Adolphus College

    Science.gov (United States)

    Hulseberg, Anna; Monson, Sarah

    2009-01-01

    Electronic resources, the tools we use to manage them, and the needs and expectations of our users are constantly evolving; at the same time, the roles, responsibilities, and workflow of the library staff who manage e-resources are also in flux. Recognizing a need to be more intentional and proactive about how we manage e-resources, the…

  10. NASA Prediction of Worldwide Energy Resource High Resolution Meteorology Data For Sustainable Building Design

    Science.gov (United States)

    Chandler, William S.; Hoell, James M.; Westberg, David; Zhang, Taiping; Stackhouse, Paul W., Jr.

    2013-01-01

    A primary objective of NASA's Prediction of Worldwide Energy Resource (POWER) project is to adapt and infuse NASA's solar and meteorological data into the energy, agricultural, and architectural industries. Improvements are continuously incorporated when higher resolution and longer-term data inputs become available. Climatological data previously provided via POWER web applications were three-hourly and 1x1 degree latitude/longitude. The NASA Modern Era Retrospective-analysis for Research and Applications (MERRA) data set provides higher resolution data products (hourly and 1/2x1/2 degree) covering the entire globe. Currently POWER solar and meteorological data are available for more than 30 years on hourly (meteorological only), daily, monthly and annual time scales. These data may be useful to several renewable energy sectors: solar and wind power generation, agricultural crop modeling, and sustainable buildings. A recent focus has been working with ASHRAE to assess complementing weather station data with MERRA data. ASHRAE building design parameters being investigated include heating/cooling degree days and climate zones.

  11. Provincial Water Resource Allocation in Agricultural Sector Using Conflict Resolution Methods in Atrak Basin

    Directory of Open Access Journals (Sweden)

    Parvaneh KazemiMeresht

    2017-03-01

    Full Text Available Introduction: In spite of improving the water productivity due to development in water infrastructure systems, population increasing causing the water withdrawal is triple in the last fifty years. In this situation competition on water consumption especially in the agricultural sector which is the biggest consumer in the world and also in Iran is a severe problem. Water allocation has been assessed widely in the recent past. Additionally, several studies have explored methods to incorporate conflict resolution methods in water allocation. In a general classification, there are two types of methods. One is the method based on game theory, graph theory and general models based oncooperative game into a category that has the ability to consider the stakeholder preferences and assess the several scenarios under specified policy. Although this type of methods iseligible to cooperate the stakeholder in modeling but due to their weakness on considering the information on details and their limitations in adoption with changes caused from uncertainty, they are not popular in practical cases. Another type of conflict resolution method which is eligible to considering more detailed information of systems has the optimization approach basically, has the most interests between researchers. There is namely the Nash bargaining solution, the Kalai-Smorodinesky solution, the Equal loss solution and the area monotonic solution. There are several studies which areapplied these methods to investigate about groundwater (5, 6 and10. There are a few applications of water resource allocation models which is incorporated with conflict resolution methods in Transboundary Rivers nowadays and restricted to game theory related methods (1 and 2. The aim of this study is the assessment of the application of conflict resolution methods such as symmetric and non symmetric Nash solution, non symmetricKalai-Smorodinesky, non symmetric equal loss solution and finally the area

  12. Toward electron exit wave tomography of amorphous materials at atomic resolution

    Energy Technology Data Exchange (ETDEWEB)

    Borisenko, Konstantin B., E-mail: konstantin.borisenko@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Moldovan, Grigore [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Kirkland, Angus I., E-mail: angus.kirkland@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Van Dyck, Dirk [Department of Physics, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Tang, Hsin-Yu; Chen, Fu-Rong [Department of Engineering and System Science, National Tsing Hua University, Kuang-Fu Road, 300 Hsinchu, Taiwan (China)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer We suggest a novel electron exit wave tomography approach to obtain three dimensional atomic structures of amorphous materials. Black-Right-Pointing-Pointer Theoretical tests using a model of amorphous Si doped with Au show that it is feasible to reconstruct both Si and Au atoms positions. Black-Right-Pointing-Pointer Reconstructions of the strongly scattering Au atoms positions appear to be insensitive to typical experimental errors. - Abstract: We suggest to use electron exit wave phase for tomographic reconstruction of structure of Au-doped amorphous Si with atomic resolution. In the present theoretical investigation into the approach it is found that the number of projections and the accuracy of defocus in the focal series restoration are the main factors that contribute to the final resolution. Although resolution is ultimately limited by these factors, phase shifts in the exit wave are sufficient to identify the position of Au atoms in an amorphous Si needle model, even when only 19 projections with defocus error of 4 nm are used. Electron beam damage will probably further limit the resolution of such tomographic reconstructions, however beam damage can be mitigated using lower accelerating voltages.

  13. ELECTRON BUNCH CHARACTERIZATION WITH SUBPICOSECOND RESOLUTION USING ELECTRO-OPTIC TECHNIQUE

    International Nuclear Information System (INIS)

    SEMERTZIDIS, Y.K.; CASTILLO, V.; LARSEN, R.; LAZARUS, D.M.; NIKAS, D.; OZBEN, C.; SRINIVASAN-RAO, T.; STILLMAN, A.; TSANG, T.; KOWALSKI, L.

    2001-01-01

    In the past decade, the bunch lengths of electrons in accelerators have decreased dramatically and are in the range off a few millimeters. Measurement of the length as well as the longitudinal profile of these short bunches have been a topic of research in a number of institutions. One of the techniques uses the electric field induced by the passage of electrons in the vicinity of a birefringent crystal to change its optical characteristics. Well-established electro-optic techniques can then be used to measure the temporal characteristics of the electron bunch. The inherent fast response of the crystal facilitates the measurement to femtosecond time resolution. However, the resolution in experiments so far has been limited to 70 ps, by the bandwidth of the detection equipment. Use of a streak camera can improve this resolution to a few picoseconds. In this paper we present a novel, non-invasive, single-shot approach to improve the resolution to tens of femtoseconds so that sub mm bunch length can be measured

  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. Strain mapping for the semiconductor industry by dark-field electron holography and nanobeam electron diffraction with nm resolution

    International Nuclear Information System (INIS)

    Cooper, David; Hartmann, Jean Michel; Carron, Veronique; Béché, Armand; Rouvière, Jean-Luc

    2010-01-01

    There is a requirement of the semiconductor industry to measure strain in semiconductor devices with nm-scale resolution. Here we show that dark-field electron holography and nanobeam electron diffraction (NBED) are both complementary techniques that can be used to determine the strain in these devices. We show two-dimensional strain maps acquired by dark holography and line profiles that have been acquired by NBED of recessed SiGe sources and drains with a variety of different gate lengths and Ge concentrations. We have also used dark-field electron holography to measure the evolution in strain during the silicidation process, showing that this can reduce the applied uniaxial compressive strain in the conduction channel by up to a factor of 3

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

    Energy Technology Data Exchange (ETDEWEB)

    Lestinsky, M.

    2007-04-18

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

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

    International Nuclear Information System (INIS)

    Lestinsky, M.

    2007-01-01

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

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

    International Nuclear Information System (INIS)

    Sinclair, R.

    1982-01-01

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

  19. impact of the use of electronic resources on research output

    African Journals Online (AJOL)

    manda

    ... Julita Nawe. University of Dar Es Salaam Library, P.O. Box 35092, Dar Es Salaam, Tanzania .... significantly, while 28.3% observed that quality of service to the community had improved .... resources and evaluate them is an important area.

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

    International Nuclear Information System (INIS)

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

    1979-01-01

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

  1. Temporal resolution criterion for correctly simulating relativistic electron motion in a high-intensity laser field

    Energy Technology Data Exchange (ETDEWEB)

    Arefiev, Alexey V. [Institute for Fusion Studies, The University of Texas, Austin, Texas 78712 (United States); Cochran, Ginevra E.; Schumacher, Douglass W. [Physics Department, The Ohio State University, Columbus, Ohio 43210 (United States); Robinson, Alexander P. L. [Central Laser Facility, STFC Rutherford-Appleton Laboratory, Didcot OX11 0QX (United Kingdom); Chen, Guangye [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2015-01-15

    Particle-in-cell codes are now standard tools for studying ultra-intense laser-plasma interactions. Motivated by direct laser acceleration of electrons in sub-critical plasmas, we examine temporal resolution requirements that must be satisfied to accurately calculate electron dynamics in strong laser fields. Using the motion of a single electron in a perfect plane electromagnetic wave as a test problem, we show surprising deterioration of the numerical accuracy with increasing wave amplitude a{sub 0} for a given time-step. We go on to show analytically that the time-step must be significantly less than λ/ca{sub 0} to achieve good accuracy. We thus propose adaptive electron sub-cycling as an efficient remedy.

  2. Improved Temperature Diagnostic for Non-Neutral Plasmas with Single-Electron Resolution

    Science.gov (United States)

    Shanman, Sabrina; Evans, Lenny; Fajans, Joel; Hunter, Eric; Nelson, Cheyenne; Sierra, Carlos; Wurtele, Jonathan

    2016-10-01

    Plasma temperature diagnostics in a Penning-Malmberg trap are essential for reliably obtaining cold, non-neutral plasmas. We have developed a setup for detecting the initial electrons that escape from a trapped pure electron plasma as the confining electrode potential is slowly reduced. The setup minimizes external noise by using a silicon photomultiplier to capture light emitted from an MCP-amplified phosphor screen. To take advantage of this enhanced resolution, we have developed a new plasma temperature diagnostic analysis procedure which takes discrete electron arrival times as input. We have run extensive simulations comparing this new discrete algorithm to our existing exponential fitting algorithm. These simulations are used to explore the behavior of these two temperature diagnostic procedures at low N and at high electronic noise. This work was supported by the DOE DE-FG02-06ER54904, and the NSF 1500538-PHY.

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

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  4. Preservation of and Permanent Access to Electronic Information Resources

    National Research Council Canada - National Science Library

    Hodge, Gail

    2004-01-01

    The rapid growth in the creation and dissemination of electronic information has emphasized the digital environment's speed and ease of dissemination with little regard for its long-term preservation and access...

  5. Optical and mechanical design for 1 nm resolution Auger spectroscopy in an electron microscope

    International Nuclear Information System (INIS)

    Bleeker, A.J.

    1991-01-01

    Detailed information about the atomic structure of surfaces and interfaces is vital for the progress in materials science and physics. One widely used surface sensitive technique is Auger spectroscopy (AS). This technique, in which the electron energy spectrum emerging from the sample is evaluated, gives information about the average elemental composition of the surface over a relative large surface area (>30nm). Electron microscopy (EM), on the other hand, is capable of producing surface structural, but no elemental, information with almost atomic resolution. EM and AS techniques have not been combined so far because of the different nature of the instrumentation used in both techniques. In AS instruments the sample is placed in an Ultra High Vacuum (UHV) system with a relatively large open space around the sample. In EM the sample is situated in the tight volume between the magnetic polepieces of the probe forming objective lens. The space around the sample is therefore tight. Furthermore the vacuum in most electron microscopes is not in UHV range. Radical mechanical changes to improve the vacuum are necessary to do AS in an electron microscope. Since the sample is immersed in the strong magnetic field of the objective lens the Auger electrons can not be extracted with conventional electrostatical methods. The only possibility to extract the Auger electrons is through the upper bore of the objective lens. However, this has large implications on the optical system of the microscope and requires a thorough investigation of the extraction of the Auger electrons. In this work it will be discussed how the surface sensitive AS can be combined with the high spatial resolution of the electron microscope in a practical instrument. (author). 102 refs.; 81 figs.; 4 tabs

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

    International Nuclear Information System (INIS)

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

    1993-01-01

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

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

    Science.gov (United States)

    Russo, Christopher J.; Passmore, Lori A.

    2016-01-01

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

  8. Performance of ultrahigh resolution electron microscope JEM-4000EX and some applications of high Tc superconductors

    International Nuclear Information System (INIS)

    Honda, T.; Ibe, K.; Ishida, Y.; Kersker, M.M.

    1989-01-01

    The high resolution electron microscope is powerful for modern materials science because of its direct observation capability for the atomic structure of materials. the JEM-4000EX, a 400 kV accelerating voltage electron microscope whose objective lens has a 1 mm spherical aberration coefficient, has a 0.168 nm theoretical resolving power. Using this microscope, atomic structure images of high Tc superconductor such as Y-Ba-Cu-O, Bi-Ca-Sr-Cu-O and Tl-Ca-Ba-Cu-O are reported

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

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

    Science.gov (United States)

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

    2010-06-07

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

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

    Science.gov (United States)

    Hayashi, Y

    1994-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-02-01

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

  13. Electronic conferencing for continuing medical education: a resource survey.

    Science.gov (United States)

    Sternberg, R J

    1986-10-01

    The use of electronic technologies to link participants for education conferences is an option for providers of Continuing Medical Education. In order to profile the kinds of electronic networks currently offering audio- or videoteleconferences for physician audiences, a survey was done during late 1985. The information collected included range of services, fees, and geographic areas served. The results show a broad diversity of providers providing both interactive and didactic programming to both physicians and other health care professionals.

  14. High spatial resolution upgrade of the electron cyclotron emission radiometer for the DIII-D tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Truong, D. D., E-mail: dtruong@wisc.edu [Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Austin, M. E. [Institute for Fusion Studies, University of Texas, Austin, Texas, 78712 (United States)

    2014-11-15

    The 40-channel DIII-D electron cyclotron emission (ECE) radiometer provides measurements of T{sub e}(r,t) at the tokamak midplane from optically thick, second harmonic X-mode emission over a frequency range of 83–130 GHz. The frequency spacing of the radiometer's channels results in a spatial resolution of ∼1–3 cm, depending on local magnetic field and electron temperature. A new high resolution subsystem has been added to the DIII-D ECE radiometer to make sub-centimeter (0.6–0.8 cm) resolution T{sub e} measurements. The high resolution subsystem branches off from the regular channels’ IF bands and consists of a microwave switch to toggle between IF bands, a switched filter bank for frequency selectivity, an adjustable local oscillator and mixer for further frequency down-conversion, and a set of eight microwave filters in the 2–4 GHz range. Higher spatial resolution is achieved through the use of a narrower (200 MHz) filter bandwidth and closer spacing between the filters’ center frequencies (250 MHz). This configuration allows for full coverage of the 83–130 GHz frequency range in 2 GHz bands. Depending on the local magnetic field, this translates into a “zoomed-in” analysis of a ∼2–4 cm radial region. Expected uses of these channels include mapping the spatial dependence of Alfven eigenmodes, geodesic acoustic modes, and externally applied magnetic perturbations. Initial T{sub e} measurements, which demonstrate that the desired resolution is achieved, are presented.

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

    Science.gov (United States)

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

    2014-10-01

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

  16. Methods For Electron Bunch Measurement With Resolution Of The Order Of 1 Fs And 1 Nm

    CERN Document Server

    Tron, A M

    2004-01-01

    Methods for bunch length and shape monitoring with femtosecond resolution by means of time converting photochronography of the bunch radiation in the range of visible light using photoelectron camera of new principle of its operation, and for monitoring the transverse bunch size, based on new beam cross section wire scanner technique where the depth of electron escapement being not more than 1 nm is used, are described. Main limitation, caused by space charge effect, is considered.

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  18. Double-resolution electron holography with simple Fourier transform of fringe-shifted holograms

    International Nuclear Information System (INIS)

    Volkov, V.V.; Han, M.G.; Zhu, Y.

    2013-01-01

    We propose a fringe-shifting holographic method with an appropriate image wave recovery algorithm leading to exact solution of holographic equations. With this new method the complex object image wave recovered from holograms appears to have much less traditional artifacts caused by the autocorrelation band present practically in all Fourier transformed holograms. The new analytical solutions make possible a double-resolution electron holography free from autocorrelation band artifacts and thus push the limits for phase resolution. The new image wave recovery algorithm uses a popular Fourier solution of the side band-pass filter technique, while the fringe-shifting holographic method is simple to implement in practice. - Highlights: • We propose a fringe-shifting holographic method simple enough for practical implementations. • Our new image-wave-recovery algorithm follows from exact solution of holographic equations. • With autocorrelation band removal from holograms it is possible to achieve double-resolution electron holography data free from several commonly known artifacts. • The new fringe-shifting method can reach an image wave resolution close to single fringe spacing

  19. Double-resolution electron holography with simple Fourier transform of fringe-shifted holograms

    Energy Technology Data Exchange (ETDEWEB)

    Volkov, V.V., E-mail: volkov@bnl.gov; Han, M.G.; Zhu, Y.

    2013-11-15

    We propose a fringe-shifting holographic method with an appropriate image wave recovery algorithm leading to exact solution of holographic equations. With this new method the complex object image wave recovered from holograms appears to have much less traditional artifacts caused by the autocorrelation band present practically in all Fourier transformed holograms. The new analytical solutions make possible a double-resolution electron holography free from autocorrelation band artifacts and thus push the limits for phase resolution. The new image wave recovery algorithm uses a popular Fourier solution of the side band-pass filter technique, while the fringe-shifting holographic method is simple to implement in practice. - Highlights: • We propose a fringe-shifting holographic method simple enough for practical implementations. • Our new image-wave-recovery algorithm follows from exact solution of holographic equations. • With autocorrelation band removal from holograms it is possible to achieve double-resolution electron holography data free from several commonly known artifacts. • The new fringe-shifting method can reach an image wave resolution close to single fringe spacing.

  20. Controlling user access to electronic resources without password

    Science.gov (United States)

    Smith, Fred Hewitt

    2017-08-22

    Described herein are devices and techniques for remotely controlling user access to a restricted computer resource. The process includes obtaining an image from a communication device of a user. An individual and a landmark are identified within the image. Determinations are made that the individual is the user and that the landmark is a predetermined landmark. Access to a restricted computing resource is granted based on the determining that the individual is the user and that the landmark is the predetermined landmark. Other embodiments are disclosed.

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

    Directory of Open Access Journals (Sweden)

    Young-Min Kim

    2010-09-01

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

  2. Electron beam pasteurised oil palm waste: a potential feed resource

    International Nuclear Information System (INIS)

    Mat Rasol Awang; Hassan Hamdani Mutaat; Tamikazu Kume; Tachibana, H.

    2002-01-01

    Pasteurization of oil palm empty fruit bunch (EFB) was performed using electron beam single sided irradiation. The dose profiles of oil palm EFB samples for different thickness in both directions X and Y were established. The results showed the usual characteristics dose uniformity as sample thickness decreased. The mean average absorbed dose on both sides at the surface and bottom of the samples for different thickness samples lead to establishing depth dose curve. Based on depth dose curve and operation conditions of electron beam machine, the process throughput for pasteurized oil palm EFB were estimated. (Author)

  3. On the role of the gas environment, electron-dose-rate, and sample on the image resolution in transmission electron microscopy

    DEFF Research Database (Denmark)

    Ek, Martin; Jespersen, Sebastian Pirel Fredsgaard; Damsgaard, Christian Danvad

    2016-01-01

    on the electron-dose-rate. In this article, we demonstrate that both the total and areal electron-dose-rates work as descriptors for the dose-rate-dependent resolution and are related through the illumination area. Furthermore, the resolution degradation was observed to occur gradually over time after......The introduction of gaseous atmospheres in transmission electron microscopy offers the possibility of studying materials in situ under chemically relevant environments. The presence of a gas environment can degrade the resolution. Surprisingly, this phenomenon has been shown to depend...... initializing the illumination of the sample and gas by the electron beam. The resolution was also observed to be sensitive to the electrical conductivity of the sample. These observations can be explained by a charge buildup over the electron-illuminated sample area, caused by the beam–gas–sample interaction...

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

    Science.gov (United States)

    Béché, A; Juchtmans, R; Verbeeck, J

    2017-07-01

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

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

    International Nuclear Information System (INIS)

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

    1980-01-01

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

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

    Science.gov (United States)

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

    1996-03-01

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

  7. Availability of Electronic Resources for Service Provision in ...

    African Journals Online (AJOL)

    The study also revealed that majority of the University libraries have adequate basic infrastructure for effective electronic information services. ... acquired by the library are put into maximal use by the library clientele, thereby ensuring the achievement of the library's objective which is satisfying the users, information needs.

  8. Utilization of bio-resources by low energy electron beam

    International Nuclear Information System (INIS)

    Kume, Tamikazu

    2003-01-01

    Utilization of bio-resources by radiation has been investigated for recycling the natural resources and reducing the environmental pollution. Polysaccharides such as chitosan and sodium alginate were easily degraded by irradiation and induced various kinds of biological activities, i.g. anti-microbial activity, promotion of plant growth, suppression of heavy metal stress, phytoalexins induction. Radiation degraded chitosan was effective to enhance the growth of plants in tissue culture. It was demonstrated that the liquid sample irradiation system using low energy EB was effective for the preparation of degraded polysaccharides. Methylcellulose (MC) can be crosslinked under certain radiation condition as same as carboxymethylcellulose (CMC) and produced the biodegradable hydrogel for medical and agricultural use. Treatment of soybean seeds by low energy EB enhanced the growth and the number of rhizobia on the root. (author)

  9. Pulse radiolysis with (sub) nanosecond time resolution using a 3 MV electron accelerator

    International Nuclear Information System (INIS)

    Luthjens, L.H.

    1986-01-01

    In this thesis the development of equipment for pulse radiolysis is described and the application of the technique to time-resolved measurements of the fluorescence emission of excited states formed after irradiation of some alkanes is dealt with. A review is given of the development of the pulsed 3MV Van de Graaf electron accelerator for the generation of subnanosecond electron beam pulses and of the development of the equipment for optical detection as accomplished by the author. The initial stage of a further development for shorter pulses and higher time resolution is briefly discussed. A collection of papers on the development of apparatus and a collection of papers dealing with the results obtained from measurements of the fluorescence of excited states, formed by the recombination of electrons and ions in irradiated alkanes such as cyclohexane and the decalines, are included. (Auth.)

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

    International Nuclear Information System (INIS)

    Chutjian, A.

    1991-01-01

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

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

    Science.gov (United States)

    Czyrska-Filemonowicz, A; Buffat, P A

    2009-01-01

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

  12. Wind Resource Assessment in Complex Terrain with a High-Resolution Numerical Weather Prediction Model

    Science.gov (United States)

    Gruber, Karin; Serafin, Stefano; Grubišić, Vanda; Dorninger, Manfred; Zauner, Rudolf; Fink, Martin

    2014-05-01

    A crucial step in planning new wind farms is the estimation of the amount of wind energy that can be harvested in possible target sites. Wind resource assessment traditionally entails deployment of masts equipped for wind speed measurements at several heights for a reasonably long period of time. Simplified linear models of atmospheric flow are then used for a spatial extrapolation of point measurements to a wide area. While linear models have been successfully applied in the wind resource assessment in plains and offshore, their reliability in complex terrain is generally poor. This represents a major limitation to wind resource assessment in Austria, where high-altitude locations are being considered for new plant sites, given the higher frequency of sustained winds at such sites. The limitations of linear models stem from two key assumptions in their formulation, the neutral stratification and attached boundary-layer flow, both of which often break down in complex terrain. Consequently, an accurate modeling of near-surface flow over mountains requires the adoption of a NWP model with high horizontal and vertical resolution. This study explores the wind potential of a site in Styria in the North-Eastern Alps. The WRF model is used for simulations with a maximum horizontal resolution of 800 m. Three nested computational domains are defined, with the innermost one encompassing a stretch of the relatively broad Enns Valley, flanked by the main crest of the Alps in the south and the Nördliche Kalkalpen of similar height in the north. In addition to the simulation results, we use data from fourteen 10-m wind measurement sites (of which 7 are located within valleys and 5 near mountain tops) and from 2 masts with anemometers at several heights (at hillside locations) in an area of 1600 km2 around the target site. The potential for wind energy production is assessed using the mean wind speed and turbulence intensity at hub height. The capacity factor is also evaluated

  13. Spatial Statistical and Modeling Strategy for Inventorying and Monitoring Ecosystem Resources at Multiple Scales and Resolution Levels

    Science.gov (United States)

    Robin M. Reich; C. Aguirre-Bravo; M.S. Williams

    2006-01-01

    A statistical strategy for spatial estimation and modeling of natural and environmental resource variables and indicators is presented. This strategy is part of an inventory and monitoring pilot study that is being carried out in the Mexican states of Jalisco and Colima. Fine spatial resolution estimates of key variables and indicators are outputs that will allow the...

  14. Analysis of Pedagogic Potential of Electronic Educational Resources with Elements of Autodidactics

    Directory of Open Access Journals (Sweden)

    Igor A.

    2018-03-01

    Full Text Available Introduction: in recent years didactic properties of electronic educational resources undergo considerable changes, nevertheless, the question of studying of such complete phenomenon as “an electronic educational resource with autodidactics elements” remains open, despite sufficient scientific base of researches of the terms making this concept. Article purpose – determination of essence of electronic educational resources with autodidactics elements. Materials and Methods: the main method of research was the theoretical analysis of the pedagogical and psychological literature on the problem under study. We used the theoretical (analysis, synthesis, comparison and generalization methods, the method of interpretation, pedagogical modeling, and empirical methods (observation, testing, conversation, interview, analysis of students’ performance, pedagogical experiment, peer review. Results: we detected the advantages of electronic educational resources in comparison with traditional ones. The concept of autodidactics as applied to the subject of research is considered. Properties of electronic educational resources with a linear and nonlinear principle of construction are studied.The influence of the principle of construction on the development of the learners’ qualities is shown. We formulated an integral definition of electronic educational resources with elements of autodidactics, namely, the variability, adaptivity and cyclicity of training. A model of the teaching-learning process with electronic educational resources is developed. Discussion and Conclusions: further development of a problem will allow to define whether electronic educational resources with autodidactics elements pedagogical potential for realization of educational and self-educational activity of teachers have, to modify technological procedures taking into account age features of students, their specialties and features of the organization of process of training of

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

    International Nuclear Information System (INIS)

    Hofer, Werner A

    2012-01-01

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

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

    Science.gov (United States)

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

    2017-09-01

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

  17. Using elastic peak electron spectroscopy for enhanced depth resolution in sputter profiling

    International Nuclear Information System (INIS)

    Hofmann, S.; Kesler, V.

    2002-01-01

    Elastic peak electron spectroscopy (EPES) is an alternative to AES in sputter depth profiling of thin film structures. In contrast to AES, EPES depth profiling is not influenced by chemical effects. The high count rate ensures a good signal to noise ratio, that is lower measurement times and/or higher precision. In addition, because of the elastically scattered electrons travel twice through the sample, the effective escape depth is reduced, an important factor for the depth resolution function. Thus, the depth resolution is increased. EPES depth profiling was successfully applied to a Ge/Si multilayer structure. For an elastic peak energy of 1.0 keV the information depth is considerably lower (0.8 nm) as compared to the Ge (LMM, 1147 eV) peak (1.6 nm) used in AES depth profiling, resulting in a respectively improved depth resolution for EPES profiling under otherwise similar profiling conditions. EPES depth profiling is successfully applied to measure small diffusion lengths at Ge/Si interfaces of the order of 1 nm. (Authors)

  18. Contribution to the resolution of algebraic differential equations. Application to electronic circuits and nuclear reactors

    International Nuclear Information System (INIS)

    Monsef, Youssef.

    1977-05-01

    This note deals with the resolution of large algebraic differential systems involved in the physical sciences, with special reference to electronics and nuclear physics. The theoretical aspect of the algorithms established and developed for this purpose is discussed in detail. A decomposition algorithm based on the graph theory is developed in detail and the regressive analysis of the error involved in the decomposition is carried out. The specific application of these algorithms on the analyses of non-linear electronic circuits and to the integration of algebraic differential equations simulating the general operation of nuclear reactors coupled to heat exchangers is discussed in detail. To conclude, it is shown that the development of efficient digital resolution techniques dealing with the elements in order is sub-optimal for large systems and calls for the revision of conventional formulation methods. Thus for a high-order physical system, the larger, the number of auxiliary unknowns introduced, the easier the formulation and resolution, owing to the elimination of any form of complex matricial calculation such as those given by the state variables method [fr

  19. A Study on Developing Evaluation Criteria for Electronic Resources in Evaluation Indicators of Libraries

    Science.gov (United States)

    Noh, Younghee

    2010-01-01

    This study aimed to improve the current state of electronic resource evaluation in libraries. While the use of Web DB, e-book, e-journal, and other e-resources such as CD-ROM, DVD, and micro materials is increasing in libraries, their use is not comprehensively factored into the general evaluation of libraries and may diminish the reliability of…

  20. Managing Selection for Electronic Resources: Kent State University Develops a New System to Automate Selection

    Science.gov (United States)

    Downey, Kay

    2012-01-01

    Kent State University has developed a centralized system that manages the communication and work related to the review and selection of commercially available electronic resources. It is an automated system that tracks the review process, provides selectors with price and trial information, and compiles reviewers' feedback about the resource. It…

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-04-01

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

  2. Where Do Electronic Books Fit in the College Research Arsenal of Resources?

    Science.gov (United States)

    Barbier, Patricia

    2007-01-01

    Student use of electronic books has become an accepted supplement to traditional resources. Student use and satisfaction was monitored through an online course discussion board. Increased use of electronic books indicate this service is an accepted supplement to the print book collection.

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

    International Nuclear Information System (INIS)

    Hamar, G.; Varga, D.

    2012-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-12-01

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

  5. High mass-resolution electron-ion-ion coincidence measurements on core-excited organic molecules

    CERN Document Server

    Tokushima, T; Senba, Y; Yoshida, H; Hiraya, A

    2001-01-01

    Total electron-ion-ion coincidence measurements on core excited organic molecules have been carried out with high mass resolution by using multimode (reflectron/linear) time-of-flight mass analyzer. From the ion correlation spectra of core excited CH sub 3 OH and CD sub 3 OH, the reaction pathway to form H sub 3 sup + (D sub 3 sup +) is identified as the elimination of three H (D) atoms from the methyl group, not as the inter-group (-CH sub 3 and -OH) interactions. In a PEPIPICO spectrum of acetylacetone (CH sub 3 COCH sub 2 COCH sub 3) measured by using a reflectron TOF, correlations between ions up to mass number 70 with one-mass resolution was recorded.

  6. Double-resolution electron holography with simple Fourier transform of fringe-shifted holograms.

    Science.gov (United States)

    Volkov, V V; Han, M G; Zhu, Y

    2013-11-01

    We propose a fringe-shifting holographic method with an appropriate image wave recovery algorithm leading to exact solution of holographic equations. With this new method the complex object image wave recovered from holograms appears to have much less traditional artifacts caused by the autocorrelation band present practically in all Fourier transformed holograms. The new analytical solutions make possible a double-resolution electron holography free from autocorrelation band artifacts and thus push the limits for phase resolution. The new image wave recovery algorithm uses a popular Fourier solution of the side band-pass filter technique, while the fringe-shifting holographic method is simple to implement in practice. Published by Elsevier B.V.

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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

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

    International Nuclear Information System (INIS)

    Wang Zhenxia; Hu Jun; Wang Wenmin; Yu Guoqing

    1998-01-01

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

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

    Science.gov (United States)

    Crewe, Albert V.

    1996-01-01

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

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

    International Nuclear Information System (INIS)

    Thomas, G.; Westmacott, K.H.

    1978-01-01

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

  11. 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)

  12. High energy resolution and first time-dependent positron annihilation induced Auger electron spectroscopty

    International Nuclear Information System (INIS)

    Mayer, Jakob

    2010-01-01

    It was the aim of this thesis to improve the existing positron annihilation induced Auger spectrometer at the highly intense positron source NEPOMUC (NEutron induced POsitron source MUniCh) in several ways: Firstly, the measurement time for a single spectrum should be reduced from typically 12 h to roughly 1 h or even less. Secondly, the energy resolution, which amounted to ΔE/E∼10%, should be increased by at least one order of magnitude in order to make high resolution positron annihilation induced Auger spectroscopy (PAES)-measurements of Auger transitions possible and thus deliver more information about the nature of the Auger process. In order to achieve these objectives, the PAES spectrometer was equipped with a new electron energy analyzer. For its ideal operation all other components of the Auger analysis chamber had to be adapted. Particularly the sample manipulation and the positron beam guidance had to be renewed. Simulations with SIMION registered ensured the optimal positron lens parameters. After the adjustment of the new analyzer and its components, first measurements illustrated the improved performance of the PAES setup: Firstly, the measurement time for short overview measurements was reduced from 3 h to 420 s. The measurement time for more detailed Auger spectra was shortened from 12 h to 80 min. Secondly, even with the reduced measurement time, the signal to noise ratio was also enhanced by one order of magnitude. Finally, the energy resolution was improved to ΔE/E 2,3 VV-transition with PAES. Thus, within this thesis two objectives were achieved: Firstly, the PAES spectrometer was renewed and improved by at least one order of magnitude with respect to the signal to noise ratio, the measurement time and the energy resolution. Secondly, several measurements have been carried out, demonstrating the high performance of the spectrometer. Amongst them are first dynamic PAES measurements and a high resolution measurement of the CuM 2,3 VV

  13. RESOLUTION

    CERN Multimedia

    STAFF ASSOCIATION

    2010-01-01

    Research without a budget = Europe without a future !   Noting that the CERN Management has submitted to the Member States for the Finance Committee meeting on 25th August 2010 a budget for 2011 and a medium-term plan (MTP) for the period 2012-2015; Deploring the fact that, on the Member States’ request, this plan proposes a reduction of resources of 478 million Swiss francs over the period 2011–2015, compared to the initial proposal by the Management, which corresponded even then to the minimum needed to exploit the machines and experiments; Recalling that, following a decision by Council in 1996, CERN has suffered an annual budget cut of 100 million Swiss francs; Considering that this approach equates to an abandonment by the Member States of the European Union of a policy agreed upon in Barcelona in 2003 to invest 3% of their GDP in R&D by 2010, and today they can barely manage 1.85%; Considering that these budget cuts imposed on CERN compromise not on...

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  15. Electron Energy Resolution of the ATLAS TILECAL Modules with Flat Filter Method (July 2002 test beam)

    CERN Document Server

    Kulchitskii, Yu A; Vinogradov, V B

    2005-01-01

    The constructed ATLAS detector at the LHC will have the great physics discovery potential, in particular in the detection of a heavy Higgs boson. Calorimeters will play a crucial role in it. It is necessary to have confidence that the calorimeters will perform as expected. With the aim of understanding of performance of the ATLAS Tile hadronic calorimeter to electrons 12\\% of modules have been exposed in electron beams with various energies by three possible ways: cell-scan at $\\theta =20^o$ at the centers of the front face cells, $\\eta$-scan and tilerow scan at $\\theta = 90^o$ for the module side cells. We have extracted the electron energy resolutions of the $EBM-$ (ANL-44), $EBM+$ (IFA-42) and $BM$ (JINR-55) Modules of the ATLAS Tile Calorimeter at energies E = 10, 20, 50, 100 and 180 GeV and $\\theta = 20^o$ and $90^o $ and $\\eta$ scan from the July 2002 testbeam run data using the flat filter method of the PMT signal reconstruction. We have determined the statistical and constant terms for the electron en...

  16. Electron Energy Resolution of the ATLAS TILECAL Modules with Fit Filter Method (July 2002 test beam)

    CERN Document Server

    Kulchitskii, Yu A; Vinogradov, V B

    2006-01-01

    The constructed ATLAS detector at the LHC will have the great physics discovery potential, in particular in the detection of a heavy Higgs boson. Calorimeters will play a crucial role in it. It is necessary to have confidence that the calorimeters will perform as expected. With the aim of understanding of performance of the ATLAS Tile hadronic calorimeter to electrons 12\\% of modules have been exposed in electron beams with various energies by three possible ways: cell-scan at $\\theta =20^o$ at the centers of the front face cells, $\\eta$-scan and tilerow scan at $\\theta = 90^o$ for the module side cells. We have extracted the electron energy resolutions of the $EBM-$ (ANL-44), $EBM+$ (IFA-42) and $BM$ (JINR-55) Modules of the ATLAS Tile Calorimeter at energies E = 10, 20, 50, 100 and 180 GeV and $\\theta = 20^o$ and $90^o $ and $\\eta$ scan from the July 2002 testbeam run data using the fit filter method of the PMT signal reconstruction. We have determined the statistical and constant terms for the electron ene...

  17. 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.

  18. Grand Canonical adaptive resolution simulation for molecules with electrons: A theoretical framework based on physical consistency

    Science.gov (United States)

    Delle Site, Luigi

    2018-01-01

    A theoretical scheme for the treatment of an open molecular system with electrons and nuclei is proposed. The idea is based on the Grand Canonical description of a quantum region embedded in a classical reservoir of molecules. Electronic properties of the quantum region are calculated at constant electronic chemical potential equal to that of the corresponding (large) bulk system treated at full quantum level. Instead, the exchange of molecules between the quantum region and the classical environment occurs at the chemical potential of the macroscopic thermodynamic conditions. The Grand Canonical Adaptive Resolution Scheme is proposed for the treatment of the classical environment; such an approach can treat the exchange of molecules according to first principles of statistical mechanics and thermodynamic. The overall scheme is build on the basis of physical consistency, with the corresponding definition of numerical criteria of control of the approximations implied by the coupling. Given the wide range of expertise required, this work has the intention of providing guiding principles for the construction of a well founded computational protocol for actual multiscale simulations from the electronic to the mesoscopic scale.

  19. Nanometer-resolution electron microscopy through micrometers-thick water layers

    Energy Technology Data Exchange (ETDEWEB)

    Jonge, Niels de, E-mail: niels.de.jonge@vanderbilt.edu [Vanderbilt University Medical Center, Department of Molecular Physiology and Biophysics, Nashville, TN 37232-0615 (United States); Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN 37831-6064 (United States); Poirier-Demers, Nicolas; Demers, Hendrix [Universite de Sherbrooke, Electrical and Computer Engineering, Sherbrooke, Quebec J1K 2R1 (Canada); Peckys, Diana B. [Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN 37831-6064 (United States); University of Tennessee, Center for Environmental Biotechnology, Knoxville, TN 37996-1605 (United States); Drouin, Dominique [Universite de Sherbrooke, Electrical and Computer Engineering, Sherbrooke, Quebec J1K 2R1 (Canada)

    2010-08-15

    Scanning transmission electron microscopy (STEM) was used to image gold nanoparticles on top of and below saline water layers of several micrometers thickness. The smallest gold nanoparticles studied had diameters of 1.4 nm and were visible for a liquid thickness of up to 3.3 {mu}m. The imaging of gold nanoparticles below several micrometers of liquid was limited by broadening of the electron probe caused by scattering of the electron beam in the liquid. The experimental data corresponded to analytical models of the resolution and of the electron probe broadening as function of the liquid thickness. The results were also compared with Monte Carlo simulations of the STEM imaging on modeled specimens of similar geometry and composition as used for the experiments. Applications of STEM imaging in liquid can be found in cell biology, e.g., to study tagged proteins in whole eukaryotic cells in liquid and in materials science to study the interaction of solid:liquid interfaces at the nanoscale.

  20. The National Site Licensing of Electronic Resources: An Institutional Perspective

    Directory of Open Access Journals (Sweden)

    Xiaohua Zhu

    2011-06-01

    Full Text Available While academic libraries in most countries are struggling to negotiate with publishers and vendors individually or collaboratively via consortia, a few countries have experimented with a different model, national site licensing (NSL. Because NSL often involves government and large-scale collaboration, it has the potential to solve many problems in the complex licensing world. However, not many nations have adopted it. This study uses historical research approach and the comparative case study research method to explore the seemingly low level of adoption. The cases include the Canadian National Site Licensing Project (CNSLP, the United Kingdom’s National Electronic Site Licensing Initiative (NESLI, and the United States, which has not adopted NSL. The theoretical framework guiding the research design and data collection is W. Richard Scott’s institutional theory, which utilizes three supporting pillars—regulative, normative, and cultural-cognitive—to analyze institutional processes. In this study, the regulative pillar and the normative pillar of NSL adoption— an institutional construction and change—are examined. Data were collected from monographs, research articles, government documents, and relevant websites. Based on the analysis of these cases, a preliminary model is proposed for the adoption of NSL. The factors that support a country’s adoption of NSL include the need for new institutions, a centralized educational policy-making system and funding system, supportive political trends, and the tradition of cooperation. The factors that may prevent a country from adopting NSL include decentralized educational policy and funding, diversity and the large number of institutions, the concern for the “Big Deal,” and the concern for monopoly.

  1. Precision controlled atomic resolution scanning transmission electron microscopy using spiral scan pathways

    Science.gov (United States)

    Sang, Xiahan; Lupini, Andrew R.; Ding, Jilai; Kalinin, Sergei V.; Jesse, Stephen; Unocic, Raymond R.

    2017-03-01

    Atomic-resolution imaging in an aberration-corrected scanning transmission electron microscope (STEM) can enable direct correlation between atomic structure and materials functionality. The fast and precise control of the STEM probe is, however, challenging because the true beam location deviates from the assigned location depending on the properties of the deflectors. To reduce these deviations, i.e. image distortions, we use spiral scanning paths, allowing precise control of a sub-Å sized electron probe within an aberration-corrected STEM. Although spiral scanning avoids the sudden changes in the beam location (fly-back distortion) present in conventional raster scans, it is not distortion-free. “Archimedean” spirals, with a constant angular frequency within each scan, are used to determine the characteristic response at different frequencies. We then show that such characteristic functions can be used to correct image distortions present in more complicated constant linear velocity spirals, where the frequency varies within each scan. Through the combined application of constant linear velocity scanning and beam path corrections, spiral scan images are shown to exhibit less scan distortion than conventional raster scan images. The methodology presented here will be useful for in situ STEM imaging at higher temporal resolution and for imaging beam sensitive materials.

  2. High-resolution satellite imagery is an important yet underutilized resource in conservation biology.

    Science.gov (United States)

    Boyle, Sarah A; Kennedy, Christina M; Torres, Julio; Colman, Karen; Pérez-Estigarribia, Pastor E; de la Sancha, Noé U

    2014-01-01

    Technological advances and increasing availability of high-resolution satellite imagery offer the potential for more accurate land cover classifications and pattern analyses, which could greatly improve the detection and quantification of land cover change for conservation. Such remotely-sensed products, however, are often expensive and difficult to acquire, which prohibits or reduces their use. We tested whether imagery of high spatial resolution (≤5 m) differs from lower-resolution imagery (≥30 m) in performance and extent of use for conservation applications. To assess performance, we classified land cover in a heterogeneous region of Interior Atlantic Forest in Paraguay, which has undergone recent and dramatic human-induced habitat loss and fragmentation. We used 4 m multispectral IKONOS and 30 m multispectral Landsat imagery and determined the extent to which resolution influenced the delineation of land cover classes and patch-level metrics. Higher-resolution imagery more accurately delineated cover classes, identified smaller patches, retained patch shape, and detected narrower, linear patches. To assess extent of use, we surveyed three conservation journals (Biological Conservation, Biotropica, Conservation Biology) and found limited application of high-resolution imagery in research, with only 26.8% of land cover studies analyzing satellite imagery, and of these studies only 10.4% used imagery ≤5 m resolution. Our results suggest that high-resolution imagery is warranted yet under-utilized in conservation research, but is needed to adequately monitor and evaluate forest loss and conversion, and to delineate potentially important stepping-stone fragments that may serve as corridors in a human-modified landscape. Greater access to low-cost, multiband, high-resolution satellite imagery would therefore greatly facilitate conservation management and decision-making.

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  4. Annular dark field electron microscope images with better than 2 A resolution at 100 kV

    International Nuclear Information System (INIS)

    Shin, D.H.; Kirkland, E.J.; Silcox, J.

    1989-01-01

    High-resolution scanning transmission electron microscope (STEM) images in the annular dark field (ADF) imaging mode approaching the theoretical point-to-point resolution limit are presented. The ADF images were obtained from a high T c superconducting YBa 2 Cu 3 O 7-x thin-film specimen at 100 kV. The 1.9 A resolution lattice image, which is the smallest lattice spacing in the specimen, corresponds to the minimum resolvable spatial frequency with 5% contrast in the contrast transfer function for annular dark field, and is smaller than the resolution limit given by the Rayleigh criterion. This demonstrates that STEM ADF imaging can have a resolution approximately 40% better than that of the bright field conventional transmission electron microscope (CTEM) imaging at Scherzer condition

  5. High energy resolution and first time-dependent positron annihilation induced Auger electron spectroscopty

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Jakob

    2010-04-03

    It was the aim of this thesis to improve the existing positron annihilation induced Auger spectrometer at the highly intense positron source NEPOMUC (NEutron induced POsitron source MUniCh) in several ways: Firstly, the measurement time for a single spectrum should be reduced from typically 12 h to roughly 1 h or even less. Secondly, the energy resolution, which amounted to {delta}E/E{approx}10%, should be increased by at least one order of magnitude in order to make high resolution positron annihilation induced Auger spectroscopy (PAES)-measurements of Auger transitions possible and thus deliver more information about the nature of the Auger process. In order to achieve these objectives, the PAES spectrometer was equipped with a new electron energy analyzer. For its ideal operation all other components of the Auger analysis chamber had to be adapted. Particularly the sample manipulation and the positron beam guidance had to be renewed. Simulations with SIMION {sup registered} ensured the optimal positron lens parameters. After the adjustment of the new analyzer and its components, first measurements illustrated the improved performance of the PAES setup: Firstly, the measurement time for short overview measurements was reduced from 3 h to 420 s. The measurement time for more detailed Auger spectra was shortened from 12 h to 80 min. Secondly, even with the reduced measurement time, the signal to noise ratio was also enhanced by one order of magnitude. Finally, the energy resolution was improved to {delta}E/E < 1. The exceptional surface sensitivity and elemental selectivity of PAES was demonstrated in measurements of Pd and Fe, both coated with Cu layers of varying thickness. PAES showed that with 0.96 monolayer of Cu on Fe, more than 55% of the detected Auger electrons stem from Cu. In the case of the Cu coated Pd sample 0.96 monolayer of Cu resulted in a Cu Auger fraction of more than 30% with PAES and less than 5% with electron induced Auger spectroscopy

  6. Impact of precipitation spatial resolution on the hydrological response of an integrated distributed water resources model

    DEFF Research Database (Denmark)

    Fu, Suhua; Sonnenborg, Torben; Jensen, Karsten Høgh

    2011-01-01

    Precipitation is a key input variable to hydrological models, and the spatial variability of the input is expected to impact the hydrological response predicted by a distributed model. In this study, the effect of spatial resolution of precipitation on runoff , recharge and groundwater head...... of the total catchment and runoff discharge hydrograph at watershed outlet. On the other hand, groundwater recharge and groundwater head were both aff ected. The impact of the spatial resolution of precipitation input is reduced with increasing catchment size. The effect on stream discharge is relatively low...... was analyzed in the Alergaarde catchment in Denmark. Six different precipitation spatial resolutions were used as inputs to a physically based, distributed hydrological model, the MIKE SHE model. The results showed that the resolution of precipitation input had no apparent effect on annual water balance...

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

    Science.gov (United States)

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

    2013-10-01

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

  8. A survey of the use of electronic scientific information resources among medical and dental students

    Directory of Open Access Journals (Sweden)

    Aarnio Matti

    2006-05-01

    Full Text Available Abstract Background To evaluate medical and dental students' utilization of electronic information resources. Methods A web survey sent to 837 students (49.9% responded. Results Twenty-four per cent of medical students and ninteen per cent of dental students searched MEDLINE 2+ times/month for study purposes, and thiry-two per cent and twenty-four per cent respectively for research. Full-text articles were used 2+ times/month by thirty-three per cent of medical and ten per cent of dental students. Twelve per cent of respondents never utilized either MEDLINE or full-text articles. In multivariate models, the information-searching skills among students were significantly associated with use of MEDLINE and full-text articles. Conclusion Use of electronic resources differs among students. Forty percent were non-users of full-text articles. Information-searching skills are correlated with the use of electronic resources, but the level of basic PC skills plays not a major role in using these resources. The student data shows that adequate training in information-searching skills will increase the use of electronic information resources.

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

    International Nuclear Information System (INIS)

    Kirn, M.

    1979-01-01

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

  10. Analytical Study of Usage of Electronic Information Resources at Pharmacopoeial Libraries in India

    Directory of Open Access Journals (Sweden)

    Sunil Tyagi

    2014-02-01

    Full Text Available The objective of this study is to know the rate and purpose of the use of e-resource by the scientists at pharmacopoeial libraries in India. Among other things, this study examined the preferences of the scientists toward printed books and journals, electronic information resources, and pattern of using e-resources. Non-probability sampling specially accidental and purposive technique was applied in the collection of primary data through administration of user questionnaire. The sample respondents chosen for the study consists of principle scientific officer, senior scientific officer, scientific officer, and scientific assistant of different division of the laboratories, namely, research and development, pharmaceutical chemistry, pharmacovigilance, pharmacology, pharmacogonosy, and microbiology. The findings of the study reveal the personal experiences and perceptions they have had on practice and research activity using e-resource. The major findings indicate that of the total anticipated participants, 78% indicated that they perceived the ability to use computer for electronic information resources. The data analysis shows that all the scientists belonging to the pharmacopoeial libraries used electronic information resources to address issues relating to drug indexes and compendia, monographs, drugs obtained through online databases, e-journals, and the Internet sources—especially polices by regulatory agencies, contacts, drug promotional literature, and standards.

  11. Traditional natural resource conflict resolution vis-à-vis formal legal ...

    African Journals Online (AJOL)

    The article analyses how the formal legal systems in Ethiopia and Kenya marginalised and prevented traditional forms of resolving conf licts over natural resources. Both countries best illustrate two rapidly growing economies in transition. However, in Ethiopia and Kenya, conflicts over natural resource have to be ...

  12. Traditional natural resource conflict resolution vis-à-vis formal legal ...

    African Journals Online (AJOL)

    resources in both countries – which adopted the Western-style systems – need to be ... Conflict is part of life, and when it is wisely handled it could serve as an engine of ... structures had different impacts on Africa's traditional institutions and systems ... natural resource related conflict is linked to the social setting and cultural.

  13. Considering Point-of-Care Electronic Medical Resources in Lieu of Traditional Textbooks for Medical Education.

    Science.gov (United States)

    Hale, LaDonna S; Wallace, Michelle M; Adams, Courtney R; Kaufman, Michelle L; Snyder, Courtney L

    2015-09-01

    Selecting resources to support didactic courses is a critical decision, and the advantages and disadvantages must be carefully considered. During clinical rotations, students not only need to possess strong background knowledge but also are expected to be proficient with the same evidence-based POC resources used by clinicians. Students place high value on “real world” learning and therefore may place more value on POC resources that they know practicing clinicians use as compared with medical textbooks. The condensed nature of PA education requires students to develop background knowledge and information literacy skills over a short period. One way to build that knowledge and those skills simultaneously is to use POC resources in lieu of traditional medical textbooks during didactic training. Electronic POC resources offer several advantages over traditional textbooks and should be considered as viable options in PA education.

  14. Elektronik Bilgi Kaynaklarının Seçimi / Selection of Electronic Information Resources

    Directory of Open Access Journals (Sweden)

    Pınar Al

    2003-04-01

    Full Text Available For many years, library users have used only from the printed media in order to get the information that they have needed. Today with the widespread use of the Web and the addition of electronic information resources to library collections, the use of information in the electronic environment as well as in printed media is started to be used. In time, such types of information resources as, electronic journals, electronic books, electronic encyclopedias, electronic dictionaries and electronic theses have been added to library collections. In this study, selection criteria that can be used for electronic information resources are discussed and suggestions are provided for libraries that try to select electronic information resources for their collections.

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

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

    International Nuclear Information System (INIS)

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

    1978-01-01

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

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

    Science.gov (United States)

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

    2011-04-01

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

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

    Science.gov (United States)

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

    2011-04-01

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

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

    International Nuclear Information System (INIS)

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

    1988-12-01

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

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

    International Nuclear Information System (INIS)

    Schumacher, P.; Greer, A.L.

    1996-01-01

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

  1. 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.

  2. Understanding deformation with high angular resolution electron backscatter diffraction (HR-EBSD)

    Science.gov (United States)

    Britton, T. B.; Hickey, J. L. R.

    2018-01-01

    High angular resolution electron backscatter diffraction (HR-EBSD) affords an increase in angular resolution, as compared to ‘conventional’ Hough transform based EBSD, of two orders of magnitude, enabling measurements of relative misorientations of 1 x 10-4 rads (~ 0.006°) and changes in (deviatoric) lattice strain with a precision of 1 x 10-4. This is achieved through direct comparison of two or more diffraction patterns using sophisticated cross-correlation based image analysis routines. Image shifts between zone axes in the two-correlated diffraction pattern are measured with sub-pixel precision and this realises the ability to measure changes in interplanar angles and lattice orientation with a high degree of sensitivity. These shifts are linked to strains and lattice rotations through simple geometry. In this manuscript, we outline the basis of the technique and two case studies that highlight its potential to tackle real materials science challenges, such as deformation patterning in polycrystalline alloys.

  3. Water resources of the Black Sea Basin at high spatial and temporal resolution

    Science.gov (United States)

    Rouholahnejad, Elham; Abbaspour, Karim C.; Srinivasan, Raghvan; Bacu, Victor; Lehmann, Anthony

    2014-07-01

    The pressure on water resources, deteriorating water quality, and uncertainties associated with the climate change create an environment of conflict in large and complex river system. The Black Sea Basin (BSB), in particular, suffers from ecological unsustainability and inadequate resource management leading to severe environmental, social, and economical problems. To better tackle the future challenges, we used the Soil and Water Assessment Tool (SWAT) to model the hydrology of the BSB coupling water quantity, water quality, and crop yield components. The hydrological model of the BSB was calibrated and validated considering sensitivity and uncertainty analysis. River discharges, nitrate loads, and crop yields were used to calibrate the model. Employing grid technology improved calibration computation time by more than an order of magnitude. We calculated components of water resources such as river discharge, infiltration, aquifer recharge, soil moisture, and actual and potential evapotranspiration. Furthermore, available water resources were calculated at subbasin spatial and monthly temporal levels. Within this framework, a comprehensive database of the BSB was created to fill the existing gaps in water resources data in the region. In this paper, we discuss the challenges of building a large-scale model in fine spatial and temporal detail. This study provides the basis for further research on the impacts of climate and land use change on water resources in the BSB.

  4. Use of electronic sales data to tailor nutrition education resources for an ethnically diverse population.

    Science.gov (United States)

    Eyles, H; Rodgers, A; Ni Mhurchu, C

    2010-02-01

    Nutrition education may be most effective when personally tailored. Individualised electronic supermarket sales data offer opportunities to tailor nutrition education using shopper's usual food purchases. The present study aimed to use individualised electronic supermarket sales data to tailor nutrition resources for an ethnically diverse population in a large supermarket intervention trial in New Zealand. Culturally appropriate nutrition education resources (i.e. messages and shopping lists) were developed with the target population (through two sets of focus groups) and ethnic researchers. A nutrient database of supermarket products was developed using retrospective sales data and linked to participant sales to allow tailoring by usual food purchases. Modified Heart Foundation Tick criteria were used to identify 'healthier' products in the database suitable for promotion in the resources. Rules were developed to create a monthly report listing the tailored and culturally targeted messages to be sent to each participant, and to produce automated, tailored shopping lists. Culturally targeted nutrition messages (n = 864) and shopping lists (n = 3 formats) were developed. The food and nutrient database (n = 3000 top-selling products) was created using 12 months of retrospective sales data, and comprised 60%'healthier' products. Three months of baseline sales data were used to determine usual food purchases. Tailored resources were successfully mailed to 123 Māori, 52 Pacific and 346 non-Māori non-Pacific participants over the 6-month trial intervention period. Electronic supermarket sales data can be used to tailor nutrition education resources for a large number of ethnically diverse supermarket shoppers.

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

    International Nuclear Information System (INIS)

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

    1976-01-01

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

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

    Science.gov (United States)

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

    2017-03-01

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

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

    Science.gov (United States)

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

    2017-11-27

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

  8. 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

  9. REVIEW OF MOODLE PLUGINS FOR DESIGNING MULTIMEDIA ELECTRONIC EDUCATIONAL RESOURCES FROM LANGUAGE DISCIPLINES

    Directory of Open Access Journals (Sweden)

    Anton M. Avramchuk

    2015-09-01

    Full Text Available Today the problem of designing multimedia electronic educational resources from language disciplines in Moodle is very important. This system has a lot of different, powerful resources, plugins to facilitate the learning of students with language disciplines. This article presents an overview and comparative analysis of the five Moodle plugins for designing multimedia electronic educational resources from language disciplines. There have been considered their key features and functionality in order to choose the best for studying language disciplines in the Moodle. Plugins are compared by a group of experts according to the criteria: efficiency, functionality and easy use. For a comparative analysis of the plugins it is used the analytic hierarchy process.

  10. Effects of the Use of Electronic Human Resource Management (EHRM Within Human Resource Management (HRM Functions at Universities

    Directory of Open Access Journals (Sweden)

    Chux Gervase Iwu

    2016-09-01

    Full Text Available This study set out to examine the effect of e-hrm systems in assisting human resource practitioners to execute their duties and responsibilities. In comparison to developed economies of the world, information technology adoption in sub-Saharan Africa has not been without certain glitches. Some of the factors that are responsible for these include poor need identification, sustainable funding, and insufficient skills. Besides these factors, there is also the issue of change management and users sticking to what they already know. Although, the above factors seem negative, there is strong evidence that information systems such as electronic human resource management present benefits to an organization. To achieve this, a dual research approach was utilized. Literature assisted immensely in both the development of the conceptual framework upon which the study hinged as well as in the development of the questionnaire items. The study also made use of an interview checklist to guide the participants. The findings reveal a mix of responses that indicate that while there are gains in adopting e-hrm systems, it is wiser to consider supporting resources as well as articulate the needs of the university better before any investment is made.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  12. Update of the FANTOM web resource: high resolution transcriptome of diverse cell types in mammals.

    Science.gov (United States)

    Lizio, Marina; Harshbarger, Jayson; Abugessaisa, Imad; Noguchi, Shuei; Kondo, Atsushi; Severin, Jessica; Mungall, Chris; Arenillas, David; Mathelier, Anthony; Medvedeva, Yulia A; Lennartsson, Andreas; Drabløs, Finn; Ramilowski, Jordan A; Rackham, Owen; Gough, Julian; Andersson, Robin; Sandelin, Albin; Ienasescu, Hans; Ono, Hiromasa; Bono, Hidemasa; Hayashizaki, Yoshihide; Carninci, Piero; Forrest, Alistair R R; Kasukawa, Takeya; Kawaji, Hideya

    2017-01-04

    Upon the first publication of the fifth iteration of the Functional Annotation of Mammalian Genomes collaborative project, FANTOM5, we gathered a series of primary data and database systems into the FANTOM web resource (http://fantom.gsc.riken.jp) to facilitate researchers to explore transcriptional regulation and cellular states. In the course of the collaboration, primary data and analysis results have been expanded, and functionalities of the database systems enhanced. We believe that our data and web systems are invaluable resources, and we think the scientific community will benefit for this recent update to deepen their understanding of mammalian cellular organization. We introduce the contents of FANTOM5 here, report recent updates in the web resource and provide future perspectives. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  13. Geomorphometry of Drainage Basin for Natural Resources Management Using High Resolution Satellite Data an Indian Example

    Science.gov (United States)

    Venkateswarlu, P.; Reddy, M. A.; Prasad, A. T.

    2003-12-01

    Application of Remote Sensing and Geographic Information System for the development of land and water resources action plan at micro level for appropriate management of land/water resources of a watershed in rain fed region of Prakasam District in Andhra Pradesh, India forms the focal theme of this paper. The quantitative description of drainage basin geometry can be effectively determined using Remote Sensing and GIS techniques. Each of the sixty-two sub-watersheds of the study area have been studied in terms of the Morphometric parameters - Stream length, Bifurcation ratio, Length ratio, Drainage density, Stream frequency, Texture ratio, Form factor, Area Perimeters, Circularity ratio and Elongation ratio and prioritized all the sub-watersheds under study. The prioritization of sub sheds based on morphometry is compared with sediment yield prioritization and found nearly same for the study area. The information obtained from the thematic maps are integrated and action plans are suggested for land and water resources development on a sustainable basis. Landuse/Landcover, Hydrogeomorphology and Soil thematic maps were generated. In addition slope and Drainage maps were prepared from Survey of India toposheets. Based on the computerized database created using ARC/INFO software, information derived in terms of natural resources and their spatial distribution was then integrated with the socio economic data to formulate an action plan, which includes suggestion of alternative Landuse/Landcover practices. Such a plan is useful for natural resources management and for improving the socio-economic status of rural population on a sustainable basis. Keywords: Natural Resources, Remote Sensing, Morphometry sustainable development.

  14. The measurement and calculation of the X-ray spatial resolution obtained in the analytical electron microscope

    International Nuclear Information System (INIS)

    Michael, J.R.; Williams, D.B.

    1990-01-01

    The X-ray microanalytical spatial resolution is determined experimentally in various analytical electron microscopes by measuring the degradation of an atomically discrete composition profile across an interphase interface in a thin-foil of Ni-Cr-Fe. The experimental spatial resolutions are then compared with calculated values. The calculated spatial resolutions are obtained by the mathematical convolution of the electron probe size with an assumed beam-broadening distribution and the single-scattering model of beam broadening. The probe size is measured directly from an image of the probe in a TEM/SETEM and indirectly from dark-field signal changes resulting from scanning the probe across the edge of an MgO crystal in a dedicated STEM. This study demonstrates the applicability of the convolution technique to the calculation of the microanalytical spatial resolution obtained in the analytical electron microscope. It is demonstrated that, contrary to popular opinion, the electron probe size has a major impact on the measured spatial resolution in foils < 150 nm thick. (author)

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

    International Nuclear Information System (INIS)

    Ghazi, M.E.

    2002-01-01

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

  16. Elemental mapping in achromatic atomic-resolution energy-filtered transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Forbes, B.D. [School of Physics, University of Melbourne, Parkville, VIC 3010 (Australia); Houben, L. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Gruenberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Mayer, J. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Gruenberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Central Facility for Electron Microscopy, RWTH Aachen University, D-52074 Aachen (Germany); Dunin-Borkowski, R.E. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Gruenberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Allen, L.J., E-mail: lja@unimelb.edu.au [School of Physics, University of Melbourne, Parkville, VIC 3010 (Australia)

    2014-12-15

    We present atomic-resolution energy-filtered transmission electron microscopy (EFTEM) images obtained with the chromatic-aberration-corrected FEI Titan PICO at the Ernst-Ruska Centre, Jülich, Germany. We find qualitative agreement between experiment and simulation for the background-subtracted EFTEM images of the Ti–L{sub 2,3} and O–K edges for a specimen of SrTiO{sub 3} oriented down the [110] zone axis. The simulations utilize the transition potential formulation for inelastic scattering, which permits a detailed investigation of contributions to the EFTEM image. We find that energy-filtered images of the Ti–L{sub 2,3} and O–K edges are lattice images and that the background-subtracted core-loss maps may not be directly interpretable as elemental maps. Simulations show that this is a result of preservation of elastic contrast, whereby the qualitative details of the image are determined primarily by elastic, coherent scattering. We show that this effect places a constraint on the range of specimen thicknesses which could theoretically yield directly useful elemental maps. In general, interpretation of EFTEM images is ideally accompanied by detailed simulations. - Highlights: • Achromatic atomic-resolution EFTEM images were obtained for STO 〈110〉. • Simulations were in qualitative agreement with Ti–L{sub 2,3} and O–K edge maps. • The experimental EFTEM maps are not directly interpretable as elemental maps. • Image intensities are strongly determined by preservation of elastic contrast. • Interpretation of EFTEM images is ideally accompanied by detailed simulations.

  17. Identifying and evaluating electronic learning resources for use in adult-gerontology nurse practitioner education.

    Science.gov (United States)

    Thompson, Hilaire J; Belza, Basia; Baker, Margaret; Christianson, Phyllis; Doorenbos, Ardith; Nguyen, Huong

    2014-01-01

    Enhancing existing curricula to meet newly published adult-gerontology advanced practice registered nurse (APRN) competencies in an efficient manner presents a challenge to nurse educators. Incorporating shared, published electronic learning resources (ELRs) in existing or new courses may be appropriate in order to assist students in achieving competencies. The purposes of this project were to (a) identify relevant available ELR for use in enhancing geriatric APRN education and (b) to evaluate the educational utility of identified ELRs based on established criteria. A multilevel search strategy was used. Two independent team members reviewed identified ELR against established criteria to ensure utility. Only resources meeting all criteria were retained. Resources were found for each of the competency areas and included formats such as podcasts, Web casts, case studies, and teaching videos. In many cases, resources were identified using supplemental strategies and not through traditional search or search of existing geriatric repositories. Resources identified have been useful to advanced practice educators in improving lecture and seminar content in a particular topic area and providing students and preceptors with additional self-learning resources. Addressing sustainability within geriatric APRN education is critical for sharing of best practices among educators and for sustainability of teaching and related resources. © 2014.

  18. 'Big Bang' tomography as a new route to atomic-resolution electron tomography.

    Science.gov (United States)

    Van Dyck, Dirk; Jinschek, Joerg R; Chen, Fu-Rong

    2012-06-13

    Until now it has not been possible to image at atomic resolution using classical electron tomographic methods, except when the target is a perfectly crystalline nano-object imaged along a few zone axes. The main reasons are that mechanical tilting in an electron microscope with sub-ångström precision over a very large angular range is difficult, that many real-life objects such as dielectric layers in microelectronic devices impose geometrical constraints and that many radiation-sensitive objects such as proteins limit the total electron dose. Hence, there is a need for a new tomographic scheme that is able to deduce three-dimensional information from only one or a few projections. Here we present an electron tomographic method that can be used to determine, from only one viewing direction and with sub-ångström precision, both the position of individual atoms in the plane of observation and their vertical position. The concept is based on the fact that an experimentally reconstructed exit wave consists of the superposition of the spherical waves that have been scattered by the individual atoms of the object. Furthermore, the phase of a Fourier component of a spherical wave increases with the distance of propagation at a known 'phase speed'. If we assume that an atom is a point-like object, the relationship between the phase and the phase speed of each Fourier component is linear, and the distance between the atom and the plane of observation can therefore be determined by linear fitting. This picture has similarities with Big Bang cosmology, in which the Universe expands from a point-like origin such that the distance of any galaxy from the origin is linearly proportional to the speed at which it moves away from the origin (Hubble expansion). The proof of concept of the method has been demonstrated experimentally for graphene with a two-layer structure and it will work optimally for similar layered materials, such as boron nitride and molybdenum disulphide.

  19. Sub-nanometre resolution imaging of polymer-fullerene photovoltaic blends using energy-filtered scanning electron microscopy.

    Science.gov (United States)

    Masters, Robert C; Pearson, Andrew J; Glen, Tom S; Sasam, Fabian-Cyril; Li, Letian; Dapor, Maurizio; Donald, Athene M; Lidzey, David G; Rodenburg, Cornelia

    2015-04-24

    The resolution capability of the scanning electron microscope has increased immensely in recent years, and is now within the sub-nanometre range, at least for inorganic materials. An equivalent advance has not yet been achieved for imaging the morphologies of nanostructured organic materials, such as organic photovoltaic blends. Here we show that energy-selective secondary electron detection can be used to obtain high-contrast, material-specific images of an organic photovoltaic blend. We also find that we can differentiate mixed phases from pure material phases in our data. The lateral resolution demonstrated is twice that previously reported from secondary electron imaging. Our results suggest that our energy-filtered scanning electron microscopy approach will be able to make major inroads into the understanding of complex, nano-structured organic materials.

  20. Sub-nanometre resolution imaging of polymer–fullerene photovoltaic blends using energy-filtered scanning electron microscopy

    Science.gov (United States)

    Masters, Robert C.; Pearson, Andrew J.; Glen, Tom S.; Sasam, Fabian-Cyril; Li, Letian; Dapor, Maurizio; Donald, Athene M.; Lidzey, David G.; Rodenburg, Cornelia

    2015-01-01

    The resolution capability of the scanning electron microscope has increased immensely in recent years, and is now within the sub-nanometre range, at least for inorganic materials. An equivalent advance has not yet been achieved for imaging the morphologies of nanostructured organic materials, such as organic photovoltaic blends. Here we show that energy-selective secondary electron detection can be used to obtain high-contrast, material-specific images of an organic photovoltaic blend. We also find that we can differentiate mixed phases from pure material phases in our data. The lateral resolution demonstrated is twice that previously reported from secondary electron imaging. Our results suggest that our energy-filtered scanning electron microscopy approach will be able to make major inroads into the understanding of complex, nano-structured organic materials. PMID:25906738

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

    Science.gov (United States)

    1994-01-01

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

  2. Direct Detection Electron Energy-Loss Spectroscopy: A Method to Push the Limits of Resolution and Sensitivity.

    Science.gov (United States)

    Hart, James L; Lang, Andrew C; Leff, Asher C; Longo, Paolo; Trevor, Colin; Twesten, Ray D; Taheri, Mitra L

    2017-08-15

    In many cases, electron counting with direct detection sensors offers improved resolution, lower noise, and higher pixel density compared to conventional, indirect detection sensors for electron microscopy applications. Direct detection technology has previously been utilized, with great success, for imaging and diffraction, but potential advantages for spectroscopy remain unexplored. Here we compare the performance of a direct detection sensor operated in counting mode and an indirect detection sensor (scintillator/fiber-optic/CCD) for electron energy-loss spectroscopy. Clear improvements in measured detective quantum efficiency and combined energy resolution/energy field-of-view are offered by counting mode direct detection, showing promise for efficient spectrum imaging, low-dose mapping of beam-sensitive specimens, trace element analysis, and time-resolved spectroscopy. Despite the limited counting rate imposed by the readout electronics, we show that both core-loss and low-loss spectral acquisition are practical. These developments will benefit biologists, chemists, physicists, and materials scientists alike.

  3. USE OF ELECTRONIC EDUCATIONAL RESOURCES WHEN TRAINING IN WORK WITH SPREADSHEETS

    Directory of Open Access Journals (Sweden)

    Х А Гербеков

    2017-12-01

    Full Text Available Today the tools for maintaining training courses based on opportunities of information and communication technologies are developed. Practically in all directions of preparation and on all subject matters electronic textbook and self-instruction manuals are created. Nevertheless the industry of computer educational and methodical materials actively develops and gets more and more areas of development and introduction. In this regard more and more urgent is a problem of development of the electronic educational resources adequate to modern educational requirements. Creation and the organization of training courses with use of electronic educational resources in particular on the basis of Internet technologies remains a difficult methodical task.In article the questions connected with development of electronic educational resources for use when studying the substantial line “Information technologies” of a school course of informatics in particular for studying of spreadsheets are considered. Also the analysis of maintenance of a school course and the unified state examination from the point of view of representation of task in him corresponding to the substantial line of studying “Information technologies” on mastering technology of information processing in spreadsheets and the methods of visualization given by means of charts and schedules is carried out.

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  5. High-Resolution Hydrological Sub-Seasonal Forecasting for Water Resources Management Over Europe

    Science.gov (United States)

    Wood, E. F.; Wanders, N.; Pan, M.; Sheffield, J.; Samaniego, L. E.; Thober, S.; Kumar, R.; Prudhomme, C.; Houghton-Carr, H.

    2017-12-01

    For decision-making at the sub-seasonal and seasonal time scale, hydrological forecasts with a high temporal and spatial resolution are required by water managers. So far such forecasts have been unavailable due to 1) lack of availability of meteorological seasonal forecasts, 2) coarse temporal resolution of meteorological seasonal forecasts, requiring temporal downscaling, 3) lack of consistency between observations and seasonal forecasts, requiring bias-correction. The EDgE (End-to-end Demonstrator for improved decision making in the water sector in Europe) project commissioned by the ECMWF (C3S) created a unique dataset of hydrological seasonal forecasts derived from four global climate models (CanCM4, FLOR-B01, ECMF, LFPW) in combination with four global hydrological models (PCR-GLOBWB, VIC, mHM, Noah-MP), resulting in 208 forecasts for any given day. The forecasts provide a daily temporal and 5-km spatial resolution, and are bias corrected against E-OBS meteorological observations. The forecasts are communicated to stakeholders via Sectoral Climate Impact Indicators (SCIIs), created in collaboration with the end-user community of the EDgE project (e.g. the percentage of ensemble realizations above the 10th percentile of monthly river flow, or below the 90th). Results show skillful forecasts for discharge from 3 months to 6 months (latter for N Europe due to snow); for soil moisture up to three months due precipitation forecast skill and short initial condition memory; and for groundwater greater than 6 months (lowest skill in western Europe.) The SCIIs are effective in communicating both forecast skill and uncertainty. Overall the new system provides an unprecedented ensemble for seasonal forecasts with significant skill over Europe to support water management. The consistency in both the GCM forecasts and the LSM parameterization ensures a stable and reliable forecast framework and methodology, even if additional GCMs or LSMs are added in the future.

  6. From Millennium ERM to Proquest 360 Resource Manager: Implementing a new Electronic Resources Management System ERMS in an International Graduate Research University in Saudi Arabia

    KAUST Repository

    Ramli, Rindra M.

    2017-01-01

    An overview of the Recommendation Study and the subsequent Implementation of a new Electronic Resources Management system ERMS in an international graduate research university in the Kingdom of Saudi Arabia. It covers the timeline, deliverables

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

    Science.gov (United States)

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

    2013-12-01

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

  8. Fuzzy cognitive maps for issue identification in a water resources conflict resolution system

    Science.gov (United States)

    Giordano, R.; Passarella, G.; Uricchio, V. F.; Vurro, M.

    In water management, conflicts of interests are inevitable due to the variety in quality demands and the number of stakeholders, which are affected in different ways by decisions concerning the use of the resources. Ignoring the differences among interests involved in water resources management and not resolving the emerging conflicts could lead to controversial strategies. In such cases, proposed solutions could generate strong opposition, making these solutions unfeasible. In our contribution, a Community Decision Support System is proposed. Such a system is able to support discussion and collaboration. The system helps participants to structure their problem, to help them learn about possible alternatives, their constraints and implications and to support the participants in the specification of their own preferences. More in detail, the proposed system helps each user in representing and communicating problem perspectives. To reach this aim, cognitive maps are used to capture parts of the stakeholders’ point of view and to enhance negotiation among individuals and organizations. The aim of the negotiation process is to define a shared cognitive map with regard to water management problems. Such a map can be called a water community cognitive map. The system performance has been tested by simulating a real conflict on water resources management that occurred some years ago in a river basin in the south of Italy.

  9. Availability, Level of Use and Constraints to Use of Electronic Resources by Law Lecturers in Public Universities in Nigeria

    Science.gov (United States)

    Amusa, Oyintola Isiaka; Atinmo, Morayo

    2016-01-01

    (Purpose) This study surveyed the level of availability, use and constraints to use of electronic resources among law lecturers in Nigeria. (Methodology) Five hundred and fifty-two law lecturers were surveyed and four hundred and forty-two responded. (Results) Data analysis revealed that the level of availability of electronic resources for the…

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-08-15

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

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

    Science.gov (United States)

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

    2010-06-01

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

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

    Science.gov (United States)

    Onozuka, Takashi; Otsuka, Nobuo; Sato, Hiroshi

    1986-09-01

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

  13. Near-Atomic Resolution Structure of a Plant Geminivirus Determined by Electron Cryomicroscopy.

    Science.gov (United States)

    Hipp, Katharina; Grimm, Clemens; Jeske, Holger; Böttcher, Bettina

    2017-08-01

    African cassava mosaic virus is a whitefly-transmitted geminivirus which forms unique twin particles of incomplete icosahedra that are joined at five-fold vertices, building an unusual waist. How its 22 capsomers interact within a half-capsid or across the waist is unknown thus far. Using electron cryo-microscopy and image processing, we determined the virion structure with a resolution of 4.2 Å and built an atomic model for its capsid protein. The inter-capsomer contacts mediated by the flexible N termini and loop regions differed within the half-capsids and at the waist, explaining partly the unusual twin structure. The tip of the pentameric capsomer is sealed by a plug formed by a turn region harboring the evolutionary conserved residue Y193. Basic amino acid residues inside the capsid form a positively charged pocket next to the five-fold axis of the capsomer suitable for binding DNA. Within this pocket, density most likely corresponding to DNA was resolved. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1975-01-01

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

  15. Electron attachment to oxygen, ozone and other compounds of atmospheric relevance as studied with ultra-high energy resolution

    International Nuclear Information System (INIS)

    Maerk, T.D.; Matejcik, S.; Kiendler, A.; Cicman, P.; Senn, G.; Skalny, J.; Stampfli, P.; Illenberger, E.; Chu, Y.; Stamatovic, A.

    1996-01-01

    The processes of electron attachment to oxygen, ozone, ozone/oxygen cluster and oxygen cluster as well as other compounds of atmospheric relevance (CF 2 Cl 2 , CHCl 3 and CCl 3 Br) were studied with ultra-high energy resolution crossed beam technique

  16. GUIDELINES FOR EVALUATION OF PSYCHOLOGICAL AND PEDAGOGICAL QUALITY CHARACTERISTICS OF ELECTRONIC EDUCATIONAL RESOURCES

    Directory of Open Access Journals (Sweden)

    Galina P. Lavrentieva

    2014-05-01

    Full Text Available The article highlights the causes of insufficient effective use of electronic learning resources and sets out the guidelines on ways to solve the aforementioned problems. The set of didactic, methodical, psychological, pedagogical, design and ergonomic quality requirements is considered for evaluation, selection and application of information and communication technologies in the educational process. The most appropriate mechanisms for the ICT introduction into the learning process are disclosed as it should meet the specific learning needs of the student and the objectives of the educational process. The guidance for psycho-educational assessment of quality of electronic educational resources is provided. It is argued that the effectiveness of the ICT use is to be improved by means of quality evaluation mechanisms involved into the educational process.

  17. Model of e-learning with electronic educational resources of new generation

    OpenAIRE

    A. V. Loban; D. A. Lovtsov

    2017-01-01

    Purpose of the article: improving of scientific and methodical base of the theory of the е-learning of variability. Methods used: conceptual and logical modeling of the е-learning of variability process with electronic educational resource of new generation and system analysis of the interconnection of the studied subject area, methods, didactics approaches and information and communication technologies means. Results: the formalization complex model of the е-learning of variability with elec...

  18. A systematic review of portable electronic technology for health education in resource-limited settings.

    Science.gov (United States)

    McHenry, Megan S; Fischer, Lydia J; Chun, Yeona; Vreeman, Rachel C

    2017-08-01

    The objective of this study is to conduct a systematic review of the literature of how portable electronic technologies with offline functionality are perceived and used to provide health education in resource-limited settings. Three reviewers evaluated articles and performed a bibliography search to identify studies describing health education delivered by portable electronic device with offline functionality in low- or middle-income countries. Data extracted included: study population; study design and type of analysis; type of technology used; method of use; setting of technology use; impact on caregivers, patients, or overall health outcomes; and reported limitations. Searches yielded 5514 unique titles. Out of 75 critically reviewed full-text articles, 10 met inclusion criteria. Study locations included Botswana, Peru, Kenya, Thailand, Nigeria, India, Ghana, and Tanzania. Topics addressed included: development of healthcare worker training modules, clinical decision support tools, patient education tools, perceptions and usability of portable electronic technology, and comparisons of technologies and/or mobile applications. Studies primarily looked at the assessment of developed educational modules on trainee health knowledge, perceptions and usability of technology, and comparisons of technologies. Overall, studies reported positive results for portable electronic device-based health education, frequently reporting increased provider/patient knowledge, improved patient outcomes in both quality of care and management, increased provider comfort level with technology, and an environment characterized by increased levels of technology-based, informal learning situations. Negative assessments included high investment costs, lack of technical support, and fear of device theft. While the research is limited, portable electronic educational resources present promising avenues to increase access to effective health education in resource-limited settings, contingent

  19. Leveraging Earth Observations to Improve Data Resolution and Tracking of Sustainable Development Goals in Water Resources and Public Health

    Science.gov (United States)

    Akanda, A. S.; Nusrat, F.; Hasan, M. A.; Fallatah, O.

    2017-12-01

    Water scarcity affects more than 40 per cent of the world population and is projected to rise substantially, affecting safe water and sanitation access globally. The recently released WHO/UNICEF Joint Monitoring Programme (JMP) 2017 report on global water and sanitation access paints a grim picture across the planet; approximately 30% people worldwide, or 2.1 billion, still lack access to safe, readily available clean water, and 60% people worldwide, or 4.5 billion ppl, lack safely managed sanitation. Meanwhile, demand for water and competition for water resources are sharply rising amid growing uncertainty of climate change and its impacts on water resources. The United Nations Agenda 2030 Sustainable Development Goals (SDGs) call for substantially increasing water-use efficiency across all sectors and ensuring sustainable withdrawals and supply of freshwater to address water scarcity, providing clean water and sanitation for all, increasing international cooperation over transboundary surface and groundwater resources (under Goal 6), as well as ending preventable deaths of newborns and children under 5 years of age, and end the epidemics of neglected tropical and water-borne diseases (under Goal 3). Data availability in developing regions, especially at the appropriate resolution in both space and time, has been a recurring problem for various technological and institutional reasons. Earth observation techniques provide the most cost-effective and encompassing tool to monitor these regions, large transboundary river basins and aquifer systems, and water resources vulnerabilities to climate change around the globe. University of Rhode Island, with US and international collaborators, is using earth observations to develop tools to analyze, monitor and support decision-makers to track their progress towards SDGs with better data resolution and accuracy. Here, we provide case studies on 1) providing safe water and sanitation access South Asia through safe water

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-12-15

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

  2. Geometrically necessary dislocation densities in olivine obtained using high-angular resolution electron backscatter diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Wallis, David, E-mail: davidwa@earth.ox.ac.uk [Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, Oxfordshire, OX1 3AN (United Kingdom); Hansen, Lars N. [Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, Oxfordshire, OX1 3AN (United Kingdom); Ben Britton, T. [Department of Materials, Imperial College London, Royal School of Mines, Exhibition Road, London SW7 2AZ (United Kingdom); Wilkinson, Angus J. [Department of Materials, University of Oxford, Parks Road, Oxford, Oxfordshire, OX1 3PH (United Kingdom)

    2016-09-15

    Dislocations in geological minerals are fundamental to the creep processes that control large-scale geodynamic phenomena. However, techniques to quantify their densities, distributions, and types over critical subgrain to polycrystal length scales are limited. The recent advent of high-angular resolution electron backscatter diffraction (HR-EBSD), based on diffraction pattern cross-correlation, offers a powerful new approach that has been utilised to analyse dislocation densities in the materials sciences. In particular, HR-EBSD yields significantly better angular resolution (<0.01°) than conventional EBSD (~0.5°), allowing very low dislocation densities to be analysed. We develop the application of HR-EBSD to olivine, the dominant mineral in Earth's upper mantle by testing (1) different inversion methods for estimating geometrically necessary dislocation (GND) densities, (2) the sensitivity of the method under a range of data acquisition settings, and (3) the ability of the technique to resolve a variety of olivine dislocation structures. The relatively low crystal symmetry (orthorhombic) and few slip systems in olivine result in well constrained GND density estimates. The GND density noise floor is inversely proportional to map step size, such that datasets can be optimised for analysing either short wavelength, high density structures (e.g. subgrain boundaries) or long wavelength, low amplitude orientation gradients. Comparison to conventional images of decorated dislocations demonstrates that HR-EBSD can characterise the dislocation distribution and reveal additional structure not captured by the decoration technique. HR-EBSD therefore provides a highly effective method for analysing dislocations in olivine and determining their role in accommodating macroscopic deformation. - Highlights: • Lattice orientation gradients in olivine were measured using HR-EBSD. • The limited number of olivine slip systems enable simple least squares inversion for GND

  3. Model of e-learning with electronic educational resources of new generation

    Directory of Open Access Journals (Sweden)

    A. V. Loban

    2017-01-01

    Full Text Available Purpose of the article: improving of scientific and methodical base of the theory of the е-learning of variability. Methods used: conceptual and logical modeling of the е-learning of variability process with electronic educational resource of new generation and system analysis of the interconnection of the studied subject area, methods, didactics approaches and information and communication technologies means. Results: the formalization complex model of the е-learning of variability with electronic educational resource of new generation is developed, conditionally decomposed into three basic components: the formalization model of the course in the form of the thesaurusclassifier (“Author of e-resource”, the model of learning as management (“Coordination. Consultation. Control”, the learning model with the thesaurus-classifier (“Student”. Model “Author of e-resource” allows the student to achieve completeness, high degree of didactic elaboration and structuring of the studied material in triples of variants: modules of education information, practical task and control tasks; the result of the student’s (author’s of e-resource activity is the thesaurus-classifier. Model of learning as management is based on the principle of personal orientation of learning in computer environment and determines the logic of interaction between the lecturer and the student when determining the triple of variants individually for each student; organization of a dialogue between the lecturer and the student for consulting purposes; personal control of the student’s success (report generation and iterative search for the concept of the class assignment in the thesaurus-classifier before acquiring the required level of training. Model “Student” makes it possible to concretize the learning tasks in relation to the personality of the student and to the training level achieved; the assumption of the lecturer about the level of training of a

  4. Atomic resolution imaging of YAlO{sub 3}: Ce in the chromatic and spherical aberration corrected PICO electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Lei [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Jülich-Aachen Research Alliance (JARA), Forschungszentrum Jülich GmbH, 52425 Jülich (Germany); Barthel, Juri [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Jülich-Aachen Research Alliance (JARA), Forschungszentrum Jülich GmbH, 52425 Jülich (Germany); Central Facility for Electron Microscopy, RWTH Aachen University, 52074 Aachen (Germany); Jia, Chun-Lin [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Jülich-Aachen Research Alliance (JARA), Forschungszentrum Jülich GmbH, 52425 Jülich (Germany); School of Electronic and Information Engineering and State Key Laboratory for Mechanical Behaviour of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Urban, Knut W., E-mail: k.urban@fz-juelich.de [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Jülich-Aachen Research Alliance (JARA), Forschungszentrum Jülich GmbH, 52425 Jülich, (Germany); School of Electronic and Information Engineering and State Key Laboratory for Mechanical Behaviour of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)

    2017-05-15

    Highlights: • First time resolution of 57 pm atom separations by HRTEM with 200 keV electrons. • Quantification of the image spread by absolute matching of experiment and simulation. • An information limit of 52 pm is deduced from the determined image spread. • Substantial deviations from the bulk structure are observed for the ultra-thin sample. - Abstract: The application of combined chromatic and spherical aberration correction in high-resolution transmission electron microscopy enables a significant improvement of the spatial resolution down to 50 pm. We demonstrate that such a resolution can be achieved in practice at 200 kV. Diffractograms of images of gold nanoparticles on amorphous carbon demonstrate corresponding information transfer. The Y atom pairs in [010] oriented yttrium orthoaluminate are successfully imaged together with the Al and the O atoms. Although the 57 pm pair separation is well demonstrated separations between 55 pm and 80 pm are measured. This observation is tentatively attributed to structural relaxations and surface reconstruction in the very thin samples used. Quantification of the resolution limiting effective image spread is achieved based on an absolute match between experimental and simulated image intensity distributions.

  5. FOLD-EM: automated fold recognition in medium- and low-resolution (4-15 Å) electron density maps.

    Science.gov (United States)

    Saha, Mitul; Morais, Marc C

    2012-12-15

    Owing to the size and complexity of large multi-component biological assemblies, the most tractable approach to determining their atomic structure is often to fit high-resolution radiographic or nuclear magnetic resonance structures of isolated components into lower resolution electron density maps of the larger assembly obtained using cryo-electron microscopy (cryo-EM). This hybrid approach to structure determination requires that an atomic resolution structure of each component, or a suitable homolog, is available. If neither is available, then the amount of structural information regarding that component is limited by the resolution of the cryo-EM map. However, even if a suitable homolog cannot be identified using sequence analysis, a search for structural homologs should still be performed because structural homology often persists throughout evolution even when sequence homology is undetectable, As macromolecules can often be described as a collection of independently folded domains, one way of searching for structural homologs would be to systematically fit representative domain structures from a protein domain database into the medium/low resolution cryo-EM map and return the best fits. Taken together, the best fitting non-overlapping structures would constitute a 'mosaic' backbone model of the assembly that could aid map interpretation and illuminate biological function. Using the computational principles of the Scale-Invariant Feature Transform (SIFT), we have developed FOLD-EM-a computational tool that can identify folded macromolecular domains in medium to low resolution (4-15 Å) electron density maps and return a model of the constituent polypeptides in a fully automated fashion. As a by-product, FOLD-EM can also do flexible multi-domain fitting that may provide insight into conformational changes that occur in macromolecular assemblies.

  6. A 20-Year High-Resolution Wave Resource Assessment of Japan with Wave-Current Interactions

    Science.gov (United States)

    Webb, A.; Waseda, T.; Kiyomatsu, K.

    2016-02-01

    Energy harvested from surface ocean waves and tidal currents has the potential to be a significant source of green energy, particularly for countries with extensive coastlines such as Japan. As part of a larger marine renewable energy project*, The University of Tokyo (in cooperation with JAMSTEC) has conducted a state-of-the-art wave resource assessment (with uncertainty estimates) to assist with wave generator site identification and construction in Japan. This assessment will be publicly available and is based on a large-scale NOAA WAVEWATCH III (version 4.18) simulation using NCEP and JAMSTEC forcings. It includes several key components to improve model skill: a 20-year simulation to reduce aleatory uncertainty, a four-nested-layer approach to resolve a 1 km shoreline, and finite-depth and current effects included in all wave power density calculations. This latter component is particularly important for regions near strong currents such as the Kuroshio. Here, we will analyze the different wave power density equations, discuss the model setup, and present results from the 20-year assessment (with a focus on the role of wave-current interactions). Time permitting, a comparison will also be made with simulations using JMA MSM 5 km winds. *New Energy and Industrial Technology Development Organization (NEDO): "Research on the Framework and Infrastructure of Marine Renewable Energy; an Energy Potential Assessment"

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

    Science.gov (United States)

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

    2016-03-01

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

  8. Phase contrast scanning transmission electron microscopy imaging of light and heavy atoms at the limit of contrast and resolution.

    Science.gov (United States)

    Yücelen, Emrah; Lazić, Ivan; Bosch, Eric G T

    2018-02-08

    Using state of the art scanning transmission electron microscopy (STEM) it is nowadays possible to directly image single atomic columns at sub-Å resolution. In standard (high angle) annular dark field STEM ((HA)ADF-STEM), however, light elements are usually invisible when imaged together with heavier elements in one image. Here we demonstrate the capability of the recently introduced Integrated Differential Phase Contrast STEM (iDPC-STEM) technique to image both light and heavy atoms in a thin sample at sub-Å resolution. We use the technique to resolve both the Gallium and Nitrogen dumbbells in a GaN crystal in [[Formula: see text

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

    Science.gov (United States)

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

    2015-08-01

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

  10. 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.

  11. Review of material recovery from used electric and electronic equipment-alternative options for resource conservation.

    Science.gov (United States)

    Friege, Henning

    2012-09-01

    For waste from electric and electronic equipment, the WEEE Directive stipulates the separate collection of electric and electronic waste. As to new electric and electronic devices, the Restriction of Hazardous Substances (RoHS) Directive bans the use of certain chemicals dangerous for man and environment. From the implementation of the WEEE directive, many unsolved problems have been documented: poor collection success, emission of dangerous substances during collection and recycling, irretrievable loss of valuable metals among others. As to RoHS, data from the literature show a satisfying success. The problems identified in the process can be reduced to some basic dilemmas at the borders between waste management, product policy and chemical safety. The objectives of the WEEE Directive and the specific targets for use and recycling of appliances are not consistent. There is no focus on scarce resources. Extended producer responsibility is not sufficient to guarantee sustainable waste management. Waste management reaches its limits due to problems of implementation but also due to physical laws. A holistic approach is necessary looking at all branch points and sinks in the stream of used products and waste from electric and electronic equipment. This may be done with respect to the general rules for sustainable management of material streams covering the three dimensions of sustainable policy. The relationships between the players in the field of electric and electronic devices have to be taken into account. Most of the problems identified in the implementation process will not be solved by the current amendment of the WEEE Directive.

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

    International Nuclear Information System (INIS)

    Krakow, W.; Shaw, T.M.

    1988-01-01

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

  13. [Use of internet and electronic resources among Spanish intensivist physicians. First national survey].

    Science.gov (United States)

    Gómez-Tello, V; Latour-Pérez, J; Añón Elizalde, J M; Palencia-Herrejón, E; Díaz-Alersi, R; De Lucas-García, N

    2006-01-01

    Estimate knowledge and use habits of different electronic resources in a sample of Spanish intensivists: Internet, E-mail, distribution lists, and use of portable electronic devices. Self-applied questionnaire. A 50-question questionnaire was distributed among Spanish intensivists through the hospital marketing delegates of a pharmaceutical company and of electronic forums. A total of 682 questionnaires were analyzed (participation: 74%). Ninety six percent of those surveyed used Internet individually: 67% admitted training gap. Internet was the second source of clinical consultations most used (61%), slightly behind consultation to colleagues (65%). The pages consulted most were bibliographic databases (65%) and electronic professional journals (63%), with limited use of Evidence Based Medicine pages (19%). Ninety percent of those surveyed used e-mail regularly in the practice of their profession, although 25% admitted that were not aware of its possibilities. The use of E-mail decreased significantly with increase in age. A total of 62% of the intensivists used distribution lists. Of the rest, 42% were not aware of its existence and 32% admitted they had insufficient training to handle them. Twenty percent of those surveyed had portable electronic devices and 64% considered it useful, basically due to its rapid consultation at bedside. Female gender was a negative predictive factor of its use (OR 0.35; 95% CI 0.2-0.63; p=0.0002). A large majority of the Spanish intensivists use Internet and E-mail. E-mail lists and use of portable devices are still underused resources. There are important gaps in training and infrequent use of essential pages. There are specific groups that require directed educational policies.

  14. High Resolution Magnetotelluric Imaging of the Nisyros Caldera and Geothermal Resource (Greece)

    Science.gov (United States)

    Tzanis, Andreas; Sakkas, Vassilis; Lagios, Evangelos

    2017-04-01

    This work reports the qualitative and quantitative re-examination of legacy magnetotelluric soundings data obtained in the caldera of Nisyros, a small island volcano at the eastern end of the Hellenic Volcanic Arc (HVA), Greece, in an attempt to explore the high temperature geothermal resource of the area. The data set comprises 39 single-site soundings and is re-examined with improved data processing methods, new hypothetical event analysis techniques to study the spatial configuration of the telluric field and two-dimensional inversion tools. Iteratively reweighted least squares have been implemented to compute stable and smooth Earth response functions, which were found to exhibit 2-D to weakly 3-D attributes as a result of induction in low-contrast local geoelectric inhomogeneities, superimposed on a dominantly 2-D background structure. The transfer functions appear to be free of coastal and island induction effects due to the low offshore/onshore resistivity contrast at, and below sea level. The spatial properties of the telluric field are studied with hypothetical event analysis based on 3-D decompositions of the impedance tensor [1]. The results indicate that convection and hydrothermal circulation is controlled by a system of antithetic NE-SW oriented active normal faults which form a graben-like structure and define the 2-D background, as well as a conjugate system of NNW-SSE normal faults which is particularly active at the SW quadrant of the island and define the main convection path. It was determined that under these conditions the data can be interpreted with 2-D inversion, which was carried out with [2]. The inversion has successfully reconstructed detailed images of the structural and functional elements of the hydrothermal system. The structural elements include a number of shallow hot water reservoirs in the argillic and phyllic alteration zones and a laterally extended deep (approx. 1km) circulation zone, all embedded in a low-resistivity matrix

  15. Hybridization approach to in-line and off-axis (electron) holography for superior resolution and phase sensitivity

    Science.gov (United States)

    Ozsoy-Keskinbora, C.; Boothroyd, C. B.; Dunin-Borkowski, R. E.; van Aken, P. A.; Koch, C. T.

    2014-01-01

    Holography - originally developed for correcting spherical aberration in transmission electron microscopes - is now used in a wide range of disciplines that involve the propagation of waves, including light optics, electron microscopy, acoustics and seismology. In electron microscopy, the two primary modes of holography are Gabor's original in-line setup and an off-axis approach that was developed subsequently. These two techniques are highly complementary, offering superior phase sensitivity at high and low spatial resolution, respectively. All previous investigations have focused on improving each method individually. Here, we show how the two approaches can be combined in a synergetic fashion to provide phase information with excellent sensitivity across all spatial frequencies, low noise and an efficient use of electron dose. The principle is also expected to be widely to applications of holography in light optics, X-ray optics, acoustics, ultra-sound, terahertz imaging, etc. PMID:25387480

  16. Super-resolution imaging based on the temperature-dependent electron-phonon collision frequency effect of metal thin films

    Science.gov (United States)

    Ding, Chenliang; Wei, Jingsong; Xiao, Mufei

    2018-05-01

    We herein propose a far-field super-resolution imaging with metal thin films based on the temperature-dependent electron-phonon collision frequency effect. In the proposed method, neither fluorescence labeling nor any special properties are required for the samples. The 100 nm lands and 200 nm grooves on the Blu-ray disk substrates were clearly resolved and imaged through a laser scanning microscope of wavelength 405 nm. The spot size was approximately 0.80 μm , and the imaging resolution of 1/8 of the laser spot size was experimentally obtained. This work can be applied to the far-field super-resolution imaging of samples with neither fluorescence labeling nor any special properties.

  17. Deceleration of probe beam by stage bias potential improves resolution of serial block-face scanning electron microscopic images.

    Science.gov (United States)

    Bouwer, James C; Deerinck, Thomas J; Bushong, Eric; Astakhov, Vadim; Ramachandra, Ranjan; Peltier, Steven T; Ellisman, Mark H

    2017-01-01

    Serial block-face scanning electron microscopy (SBEM) is quickly becoming an important imaging tool to explore three-dimensional biological structure across spatial scales. At probe-beam-electron energies of 2.0 keV or lower, the axial resolution should improve, because there is less primary electron penetration into the block face. More specifically, at these lower energies, the interaction volume is much smaller, and therefore, surface detail is more highly resolved. However, the backscattered electron yield for metal contrast agents and the backscattered electron detector sensitivity are both sub-optimal at these lower energies, thus negating the gain in axial resolution. We found that the application of a negative voltage (reversal potential) applied to a modified SBEM stage creates a tunable electric field at the sample. This field can be used to decrease the probe-beam-landing energy and, at the same time, alter the trajectory of the signal to increase the signal collected by the detector. With decelerated low landing-energy electrons, we observed that the probe-beam-electron-penetration depth was reduced to less than 30 nm in epoxy-embedded biological specimens. Concurrently, a large increase in recorded signal occurred due to the re-acceleration of BSEs in the bias field towards the objective pole piece where the detector is located. By tuning the bias field, we were able to manipulate the trajectories of the  primary and secondary electrons, enabling the spatial discrimination of these signals using an advanced ring-type BSE detector configuration or a standard monolithic BSE detector coupled with a blocking aperture.

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

    Science.gov (United States)

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

    2012-01-01

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

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

    International Nuclear Information System (INIS)

    Jia Chunlin.

    1993-08-01

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

  20. Implementing IWRM: Delivering data and models with interactive dashboards and cyberinfrastructure to facilitate natural resource conflict resolution and valuation

    Science.gov (United States)

    Pierce, S. A.; Figueroa B, E.

    2016-12-01

    Sound science and adequate models of systems are necessary for environmental decisions, yet frequently it is insufficient. This study documents the outcome of a co-design effort that was convened initially to explore the potential role that technology may have in supporting multi-stakeholder deliberation about sustainability transitions for a region. The project aims to create science-based deliberation among diverse stakeholders about water-energy-mineral use and choices in the Atacama Desert region of Chile. An interactive dashboard that pairs stakeholder preferences, concept maps with natural resource valuation models seeks to visualize useful information. The ultimate goal is to improve levels of understanding and open possibilities for collaborative problem solving by engaging industry, academics, and indigenous communities in a long- term participatory modeling process. Collaborative discussions build technical knowledge and bridge across sectors that are often at odds over management of earth resources. The project began in the shadow of marked conflict and tensions among participants. Methodologically, tensions have been reduced by combining social process with information delivery that leverages interactive touch screen applications. Models and information act as boundary objects among participants and the tenets of a conflict resolution process called sustained dialogue provide guidance for facilitating the group sessions. Early results indicate that the gesture-enabled touch screens are useful for establishing an accessible environment for deliberation because subject matter experts and laypeople can interact with information with equal ease. Social process has been critical for bridging scales, managing group expectations and relationships, and addressing differences in epistemological and cultural perspectives. Recent incorporation of economic and resource valuation highlights new aspects and alternative views of tradeoffs and potential impacts.

  1. The Synthesis of the Hierarchical Structure of Information Resources for Management of Electronic Commerce Entities

    Directory of Open Access Journals (Sweden)

    Krutova Anzhelika S.

    2017-06-01

    Full Text Available The aim of the article is to develop the theoretical bases for the classification and coding of economic information and the scientific justification of the content of information resources of an electronic commerce enterprise. The essence of information resources for management of electronic business entities is investigated. It is proved that the organization of accounting in e-commerce systems is advisable to be built on the basis of two circuits: accounting for financial flows and accounting associated with transformation of business factors in products and services as a result of production activities. There presented a sequence of accounting organization that allows to combine the both circuits in a single information system, which provides a possibility for the integrated replenishment and distributed simultaneous use of the e-commerce system by all groups of users. It is proved that the guarantee of efficient activity of the information management system of electronic commerce entities is a proper systematization of the aggregate of information resources on economic facts and operations of an enterprise in accordance with the management tasks by building the hierarchy of accounting nomenclatures. It is suggested to understand nomenclature as an objective, primary information aggregate concerning a certain fact of the economic activity of an enterprise, which is characterized by minimum requisites, is entered into the database of the information system and is to be reflected in the accounting system. It is proposed to build a database of e-commerce systems as a part of directories (constants, personnel, goods / products, suppliers, buyers and the hierarchy of accounting nomenclatures. The package of documents regulating the organization of accounting at an enterprise should include: the provision on the accounting services, the order on the accounting policy, the job descriptions, the schedules of information exchange, the report card and

  2. 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

  3. Ultrahigh resolution focused electron beam induced processing: the effect of substrate thickness

    DEFF Research Database (Denmark)

    van Dorp, Willem F; Lazic, Ivan; Beyer, André

    2011-01-01

    It is often suggested that the growth in focused electron beam induced processing (FEBIP) is caused not only by primary electrons, but also (and even predominantly) by secondary electrons (SEs). If that is true, the growth rate for FEBIP can be changed by modifying the SE yield. Results from our ...

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

    International Nuclear Information System (INIS)

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

    1991-01-01

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

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

    Science.gov (United States)

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

    2015-01-07

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

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

    International Nuclear Information System (INIS)

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

    1991-01-01

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

  7. Reconstruction of high temporal resolution Thomson scattering data during a modulated electron cyclotron resonance heating using conditional averaging

    International Nuclear Information System (INIS)

    Kobayashi, T.; Yoshinuma, M.; Ohdachi, S.; Ida, K.; Itoh, K.; Moon, C.; Yamada, I.; Funaba, H.; Yasuhara, R.; Tsuchiya, H.; Yoshimura, Y.; Igami, H.; Shimozuma, T.; Kubo, S.; Tsujimura, T. I.; Inagaki, S.

    2016-01-01

    This paper provides a software application of the sampling scope concept for fusion research. The time evolution of Thomson scattering data is reconstructed with a high temporal resolution during a modulated electron cyclotron resonance heating (MECH) phase. The amplitude profile and the delay time profile of the heat pulse propagation are obtained from the reconstructed signal for discharges having on-axis and off-axis MECH depositions. The results are found to be consistent with the MECH deposition.

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

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  9. Reconstruction of high temporal resolution Thomson scattering data during a modulated electron cyclotron resonance heating using conditional averaging

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, T., E-mail: kobayashi.tatsuya@LHD.nifs.ac.jp; Yoshinuma, M.; Ohdachi, S. [National Institute for Fusion Science, Toki 509-5292 (Japan); SOKENDAI (The Graduate University for Advanced Studies), Toki 509-5292 (Japan); Ida, K. [National Institute for Fusion Science, Toki 509-5292 (Japan); SOKENDAI (The Graduate University for Advanced Studies), Toki 509-5292 (Japan); Research Center for Plasma Turbulence, Kyushu University, Kasuga 816-8580 (Japan); Itoh, K. [National Institute for Fusion Science, Toki 509-5292 (Japan); Research Center for Plasma Turbulence, Kyushu University, Kasuga 816-8580 (Japan); Moon, C.; Yamada, I.; Funaba, H.; Yasuhara, R.; Tsuchiya, H.; Yoshimura, Y.; Igami, H.; Shimozuma, T.; Kubo, S.; Tsujimura, T. I. [National Institute for Fusion Science, Toki 509-5292 (Japan); Inagaki, S. [Research Center for Plasma Turbulence, Kyushu University, Kasuga 816-8580 (Japan); Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8580 (Japan)

    2016-04-15

    This paper provides a software application of the sampling scope concept for fusion research. The time evolution of Thomson scattering data is reconstructed with a high temporal resolution during a modulated electron cyclotron resonance heating (MECH) phase. The amplitude profile and the delay time profile of the heat pulse propagation are obtained from the reconstructed signal for discharges having on-axis and off-axis MECH depositions. The results are found to be consistent with the MECH deposition.

  10. ELECTRONIC EDUCATIONAL RESOURCES FOR ONLINE SUPPORT OF MODERN CHEMISTRY CLASSES IN SPECIALIZED SCHOOL

    Directory of Open Access Journals (Sweden)

    Maria D. Tukalo

    2013-09-01

    Full Text Available This article contains material of some modern electronic educational resources that can be used via the Internet to support the modern chemistry classes in specialized school. It was drawn attention to the educational chemical experiments as means of knowledge; simulated key motivational characteristics to enhance students interest for learning subjects, their cognitive and practical activity in the formation of self-reliance and self-creative; commented forecasts for creating of conditions to enhance the creative potential of students in a modern learning environment.

  11. THE MODEL OF LINGUISTIC TEACHERS’ COMPETENCY DEVELOPMENT ON DESIGNING MULTIMEDIA ELECTRONIC EDUCATIONAL RESOURCES IN THE MOODLE SYSTEM

    Directory of Open Access Journals (Sweden)

    Anton M. Avramchuk

    2017-10-01

    Full Text Available The article is devoted to the problem of developing the competency of teachers of language disciplines on designing multimedia electronic educational resources in the Moodle system. The concept of "the competence of teachers of language disciplines on designing multimedia electronic educational resources in the Moodle system" is justified and defined. Identified and characterized the components by which the levels of the competency development of teachers of language disciplines on designing multimedia electronic educational resources in the Moodle system should be assessed. Developed a model for the development of the competency of teachers of language disciplines on designing multimedia electronic educational resources in the Moodle system, which is based on the main scientific approaches, used in adult education, and consists of five blocks: target, informative, technological, diagnostic and effective.

  12. A preliminary categorization of end-of-life electrical and electronic equipment as secondary metal resources

    International Nuclear Information System (INIS)

    Oguchi, Masahiro; Murakami, Shinsuke; Sakanakura, Hirofumi; Kida, Akiko; Kameya, Takashi

    2011-01-01

    Highlights: → End-of-life electrical and electronic equipment (EEE) as secondary metal resources. → The content and the total amount of metals in specific equipment are both important. → We categorized 21 EEE types from contents and total amounts of various metals. → Important equipment types as secondary resources were listed for each metal kind. → Collectability and possible collection systems of various EEE types were discussed. - Abstract: End-of-life electrical and electronic equipment (EEE) has recently received attention as a secondary source of metals. This study examined characteristics of end-of-life EEE as secondary metal resources to consider efficient collection and metal recovery systems according to the specific metals and types of EEE. We constructed an analogy between natural resource development and metal recovery from end-of-life EEE and found that metal content and total annual amount of metal contained in each type of end-of-life EEE should be considered in secondary resource development, as well as the collectability of the end-of-life products. We then categorized 21 EEE types into five groups and discussed their potential as secondary metal resources. Refrigerators, washing machines, air conditioners, and CRT TVs were evaluated as the most important sources of common metals, and personal computers, mobile phones, and video games were evaluated as the most important sources of precious metals. Several types of small digital equipment were also identified as important sources of precious metals; however, mid-size information and communication technology (ICT) equipment (e.g., printers and fax machines) and audio/video equipment were shown to be more important as a source of a variety of less common metals. The physical collectability of each type of EEE was roughly characterized by unit size and number of end-of-life products generated annually. Current collection systems in Japan were examined and potentially appropriate collection

  13. Open-Source Electronic Health Record Systems for Low-Resource Settings: Systematic Review.

    Science.gov (United States)

    Syzdykova, Assel; Malta, André; Zolfo, Maria; Diro, Ermias; Oliveira, José Luis

    2017-11-13

    Despite the great impact of information and communication technologies on clinical practice and on the quality of health services, this trend has been almost exclusive to developed countries, whereas countries with poor resources suffer from many economic and social issues that have hindered the real benefits of electronic health (eHealth) tools. As a component of eHealth systems, electronic health records (EHRs) play a fundamental role in patient management and effective medical care services. Thus, the adoption of EHRs in regions with a lack of infrastructure, untrained staff, and ill-equipped health care providers is an important task. However, the main barrier to adopting EHR software in low- and middle-income countries is the cost of its purchase and maintenance, which highlights the open-source approach as a good solution for these underserved areas. The aim of this study was to conduct a systematic review of open-source EHR systems based on the requirements and limitations of low-resource settings. First, we reviewed existing literature on the comparison of available open-source solutions. In close collaboration with the University of Gondar Hospital, Ethiopia, we identified common limitations in poor resource environments and also the main requirements that EHRs should support. Then, we extensively evaluated the current open-source EHR solutions, discussing their strengths and weaknesses, and their appropriateness to fulfill a predefined set of features relevant for low-resource settings. The evaluation methodology allowed assessment of several key aspects of available solutions that are as follows: (1) integrated applications, (2) configurable reports, (3) custom reports, (4) custom forms, (5) interoperability, (6) coding systems, (7) authentication methods, (8) patient portal, (9) access control model, (10) cryptographic features, (11) flexible data model, (12) offline support, (13) native client, (14) Web client,(15) other clients, (16) code

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

    Science.gov (United States)

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

    2013-04-28

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

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

    International Nuclear Information System (INIS)

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

    1992-01-01

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

  16. The spatial resolution of silicon-based electron detectors in beta-autoradiography.

    Science.gov (United States)

    Cabello, Jorge; Wells, Kevin

    2010-03-21

    Thin tissue autoradiography is an imaging modality where ex-vivo tissue sections are placed in direct contact with autoradiographic film. These tissue sections contain a radiolabelled ligand bound to a specific biomolecule under study. This radioligand emits beta - or beta+ particles ionizing silver halide crystals in the film. High spatial resolution autoradiograms are obtained using low energy radioisotopes, such as (3)H where an intrinsic 0.1-1 microm spatial resolution can be achieved. Several digital alternatives have been presented over the past few years to replace conventional film but their spatial resolution has yet to equal film, although silicon-based imaging technologies have demonstrated higher sensitivity compared to conventional film. It will be shown in this work how pixel size is a critical parameter for achieving high spatial resolution for low energy uncollimated beta imaging. In this work we also examine the confounding factors impeding silicon-based technologies with respect to spatial resolution. The study considers charge diffusion in silicon and detector noise, and this is applied to a range of radioisotopes typically used in autoradiography. Finally an optimal detector geometry to obtain the best possible spatial resolution for a specific technology and a specific radioisotope is suggested.

  17. THE MODEL OF LINGUISTIC TEACHERS’ COMPETENCY DEVELOPMENT ON DESIGNING MULTIMEDIA ELECTRONIC EDUCATIONAL RESOURCES IN THE MOODLE SYSTEM

    OpenAIRE

    Anton M. Avramchuk

    2017-01-01

    The article is devoted to the problem of developing the competency of teachers of language disciplines on designing multimedia electronic educational resources in the Moodle system. The concept of "the competence of teachers of language disciplines on designing multimedia electronic educational resources in the Moodle system" is justified and defined. Identified and characterized the components by which the levels of the competency development of teachers of language disciplines on designing ...

  18. Spatial coherence of electron beams from field emitters and its effect on the resolution of imaged objects

    Energy Technology Data Exchange (ETDEWEB)

    Latychevskaia, Tatiana, E-mail: tatiana@physik.uzh.ch

    2017-04-15

    Sub-nanometer and nanometer-sized tips provide high coherence electron sources. Conventionally, the effective source size is estimated from the extent of the experimental biprism interference pattern created on the detector by applying the van Cittert Zernike theorem. Previously reported experimental intensity distributions on the detector exhibit Gaussian distribution and our simulations show that this is an indication that such electron sources must be at least partially coherent. This, in turn means that strictly speaking the Van Cittert Zernike theorem cannot be applied, since it assumes an incoherent source. The approach of applying the van Cittert Zernike theorem is examined in more detail by performing simulations of interference patterns for the electron sources of different size and different coherence length, evaluating the effective source size from the extent of the simulated interference pattern and comparing the obtained result with the pre-defined value. The intensity distribution of the source is assumed to be Gaussian distributed, as it is observed in experiments. The visibility or the contrast in the simulated holograms is found to be always less than 1 which agrees well with previously reported experimental results and thus can be explained solely by the Gaussian intensity distribution of the source. The effective source size estimated from the extent of the interference pattern turns out to be of about 2–3 times larger than the pre-defined size, but it is approximately equal to the intrinsic resolution of the imaging system. A simple formula for estimating the intrinsic resolution, which could be useful when employing nano-tips in in-line Gabor holography or point-projection microscopy, is provided. - Highlights: • van Cittert Zernike theorem for nano- and sub-nano electron emitting tips is revised. • Simulations show that nano- and sub-nano electron emitting tips are at least partially coherent. • A simple formula for evaluating

  19. Determining the level of awareness of the physicians in using the variety of electronic information resources and the effecting factors.

    Science.gov (United States)

    Papi, Ahmad; Ghazavi, Roghayeh; Moradi, Salimeh

    2015-01-01

    Understanding of the medical society's from the types of information resources for quick and easy access to information is an imperative task in medical researches and management of the treatment. The present study was aimed to determine the level of awareness of the physicians in using various electronic information resources and the factors affecting it. This study was a descriptive survey. The data collection tool was a researcher-made questionnaire. The study population included all the physicians and specialty physicians of the teaching hospitals affiliated to Isfahan University of Medical Sciences and numbered 350. The sample size based on Morgan's formula was set at 180. The content validity of the tool was confirmed by the library and information professionals and the reliability was 95%. Descriptive statistics were used including the SPSS software version 19. On reviewing the need of the physicians to obtain the information on several occasions, the need for information in conducting the researches was reported by the maximum number of physicians (91.9%) and the usage of information resources, especially the electronic resources, formed 65.4% as the highest rate with regard to meeting the information needs of the physicians. Among the electronic information databases, the maximum awareness was related to Medline with 86.5%. Among the various electronic information resources, the highest awareness (43.3%) was related to the E-journals. The highest usage (36%) was also from the same source. The studied physicians considered the most effective deterrent in the use of electronic information resources as being too busy and lack of time. Despite the importance of electronic information resources for the physician's community, there was no comprehensive knowledge of these resources. This can lead to less usage of these resources. Therefore, careful planning is necessary in the hospital libraries in order to introduce the facilities and full capabilities of the

  20. Success criteria for electronic medical record implementations in low-resource settings: a systematic review.

    Science.gov (United States)

    Fritz, Fleur; Tilahun, Binyam; Dugas, Martin

    2015-03-01

    Electronic medical record (EMR) systems have the potential of supporting clinical work by providing the right information at the right time to the right people and thus make efficient use of resources. This is especially important in low-resource settings where reliable data are also needed to support public health and local supporting organizations. In this systematic literature review, our objectives are to identify and collect literature about success criteria of EMR implementations in low-resource settings and to summarize them into recommendations. Our search strategy relied on PubMed queries and manual bibliography reviews. Studies were included if EMR implementations in low-resource settings were described. The extracted success criteria and measurements were summarized into 7 categories: ethical, financial, functionality, organizational, political, technical, and training. We collected 381 success criteria with 229 measurements from 47 articles out of 223 articles. Most papers were evaluations or lessons learned from African countries, published from 1999 to 2013. Almost half of the EMR systems served a specific disease area like human immunodeficiency virus (HIV). The majority of criteria that were reported dealt with the functionality, followed by organizational issues, and technical infrastructures. Sufficient training and skilled personnel were mentioned in roughly 10%. Political, ethical, and financial considerations did not play a predominant role. More evaluations based on reliable frameworks are needed. Highly reliable data handling methods, human resources and effective project management, as well as technical architecture and infrastructure are all key factors for successful EMR implementation. © The Author 2015. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

    Science.gov (United States)

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

    2015-10-01

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

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-14

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

  4. Impact of Knowledge Resources Linked to an Electronic Health Record on Frequency of Unnecessary Tests and Treatments

    Science.gov (United States)

    Goodman, Kenneth; Grad, Roland; Pluye, Pierre; Nowacki, Amy; Hickner, John

    2012-01-01

    Introduction: Electronic knowledge resources have the potential to rapidly provide answers to clinicians' questions. We sought to determine clinicians' reasons for searching these resources, the rate of finding relevant information, and the perceived clinical impact of the information they retrieved. Methods: We asked general internists, family…

  5. Resource conservation approached with an appropriate collection and upgrade-remanufacturing for used electronic products.

    Science.gov (United States)

    Zlamparet, Gabriel I; Tan, Quanyin; Stevels, A B; Li, Jinhui

    2018-03-01

    This comparative research represents an example for a better conservation of resources by reducing the amount of waste (kg) and providing it more value under the umbrella of remanufacturing. The three discussed cases will expose three issues already addressed separately in the literature. The generation of waste electrical and electronic equipment (WEEE) interacts with the environmental depletion. In this article, we gave the examples of addressed issues under the concept of remanufacturing. Online collection opportunity eliminating classical collection, a business to business (B2B) implementation for remanufactured servers and medical devices. The material reuse (recycling), component sustainability, reuse (part harvesting), product reuse (after repair/remanufacturing) indicates the recovery potential using remanufacturing tool for a better conservation of resources adding more value to the products. Our findings can provide an overview of new system organization for the general collection, market potential and the technological advantages using remanufacturing instead of recycling of WEEE or used electrical and electronic equipment. Copyright © 2017. Published by Elsevier Ltd.

  6. 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.

  7. Mapping High-Resolution Soil Moisture over Heterogeneous Cropland Using Multi-Resource Remote Sensing and Ground Observations

    Directory of Open Access Journals (Sweden)

    Lei Fan

    2015-10-01

    Full Text Available High spatial resolution soil moisture (SM data are crucial in agricultural applications, river-basin management, and understanding hydrological processes. Merging multi-resource observations is one of the ways to improve the accuracy of high spatial resolution SM data in the heterogeneous cropland. In this paper, the Bayesian Maximum Entropy (BME methodology is implemented to merge the following four types of observed data to obtain the spatial distribution of SM at 100 m scale: soil moisture observed by wireless sensor network (WSN, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER-derived soil evaporative efficiency (SEE, irrigation statistics, and Polarimetric L-band Multi-beam Radiometer (PLMR-derived SM products (~700 m. From the poor BME predictions obtained by merging only WSN and SEE data, we observed that the SM heterogeneity caused by irrigation and the attenuating sensitivity of the SEE data to SM caused by the canopies result in BME prediction errors. By adding irrigation statistics to the merged datasets, the overall RMSD of the BME predictions during the low-vegetated periods can be successively reduced from 0.052 m3·m−3 to 0.033 m3·m−3. The coefficient of determination (R2 and slope between the predicted and in situ measured SM data increased from 0.32 to 0.64 and from 0.38 to 0.82, respectively, but large estimation errors occurred during the moderately vegetated periods (RMSD = 0.041 m3·m−3, R = 0.43 and the slope = 0.41. Further adding the downscaled SM information from PLMR SM products to the merged datasets, the predictions were satisfactorily accurate with an RMSD of 0.034 m3·m−3, R2 of 0.4 and a slope of 0.69 during moderately vegetated periods. Overall, the results demonstrated that merging multi-resource observations into SM estimations can yield improved accuracy in heterogeneous cropland.

  8. Automated transmission-mode scanning electron microscopy (tSEM for large volume analysis at nanoscale resolution.

    Directory of Open Access Journals (Sweden)

    Masaaki Kuwajima

    Full Text Available Transmission-mode scanning electron microscopy (tSEM on a field emission SEM platform was developed for efficient and cost-effective imaging of circuit-scale volumes from brain at nanoscale resolution. Image area was maximized while optimizing the resolution and dynamic range necessary for discriminating key subcellular structures, such as small axonal, dendritic and glial processes, synapses, smooth endoplasmic reticulum, vesicles, microtubules, polyribosomes, and endosomes which are critical for neuronal function. Individual image fields from the tSEM system were up to 4,295 µm(2 (65.54 µm per side at 2 nm pixel size, contrasting with image fields from a modern transmission electron microscope (TEM system, which were only 66.59 µm(2 (8.160 µm per side at the same pixel size. The tSEM produced outstanding images and had reduced distortion and drift relative to TEM. Automated stage and scan control in tSEM easily provided unattended serial section imaging and montaging. Lens and scan properties on both TEM and SEM platforms revealed no significant nonlinear distortions within a central field of ∼100 µm(2 and produced near-perfect image registration across serial sections using the computational elastic alignment tool in Fiji/TrakEM2 software, and reliable geometric measurements from RECONSTRUCT™ or Fiji/TrakEM2 software. Axial resolution limits the analysis of small structures contained within a section (∼45 nm. Since this new tSEM is non-destructive, objects within a section can be explored at finer axial resolution in TEM tomography with current methods. Future development of tSEM tomography promises thinner axial resolution producing nearly isotropic voxels and should provide within-section analyses of structures without changing platforms. Brain was the test system given our interest in synaptic connectivity and plasticity; however, the new tSEM system is readily applicable to other biological systems.

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

    Science.gov (United States)

    Patterson, C H

    2012-09-07

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

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  11. Electronic theses and dissertations: a review of this valuable resource for nurse scholars worldwide.

    Science.gov (United States)

    Goodfellow, L M

    2009-06-01

    A worldwide repository of electronic theses and dissertations (ETDs) could provide worldwide access to the most up-to-date research generated by masters and doctoral students. Until that international repository is established, it is possible to access some of these valuable knowledge resources. ETDs provide a technologically advanced medium with endless multimedia capabilities that far exceed the print and bound copies of theses and dissertations housed traditionally in individual university libraries. CURRENT USE: A growing trend exists for universities worldwide to require graduate students to submit theses or dissertations as electronic documents. However, nurse scholars underutilize ETDs, as evidenced by perusing bibliographic citation lists in many of the research journals. ETDs can be searched for and retrieved through several digital resources such as the Networked Digital Library of Theses and Dissertations (http://www.ndltd.org), ProQuest Dissertations and Theses (http://www.umi.com), the Australasian Digital Theses Program (http://adt.caul.edu.au/) and through individual university web sites and online catalogues. An international repository of ETDs benefits the community of nurse scholars in many ways. The ability to access recent graduate students' research electronically from anywhere in the world is advantageous. For scholars residing in developing countries, access to these ETDs may prove to be even more valuable. In some cases, ETDs are not available for worldwide access and can only be accessed through the university library from which the student graduated. Public access to university library ETD collections is not always permitted. Nurse scholars from both developing and developed countries could benefit from ETDs.

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

    Science.gov (United States)

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

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

  13. Investigations on resolution enhancement in EPR by means of electron spin echoes

    International Nuclear Information System (INIS)

    Merks, R.P.J.

    1979-01-01

    The electron spin echo technique has been applied in four types of experiments: the measurement of electric field induced shifts of the EPR line; the detection of electron spin echo ENDOR; a relaxation measurement and the measurement of hyperfine interactions via the nuclear modulation effect. (Auth.)

  14. Testing of Track Point Resolution of Gas Electron Multiplier with Pion Beam at CERN SPS

    CERN Document Server

    Adak, R P; Das, S; Dubey, A K; Ganti, M S; Saini, J; Singaraju, R

    2015-01-01

    A muon detection system using segmented and instrumented absorber has been designed for high-energy heavy-ion collision experiments to be held at GSI, Darmstadt, Germany. The muon detector system is mounted downstream of a Silicon Tracking System. The reconstructed tracks from the STS are to be matched to the hits in the GEM detector. For reconstructing track in the GEM Detector, track point resolution is an important issue. We report her first time the track point resolution of the GEM detector.

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  17. From Millennium ERM to Proquest 360 Resource Manager: Implementing a new Electronic Resources Management System ERMS in an International Graduate Research University in Saudi Arabia

    KAUST Repository

    Ramli, Rindra M.

    2017-05-17

    An overview of the Recommendation Study and the subsequent Implementation of a new Electronic Resources Management system ERMS in an international graduate research university in the Kingdom of Saudi Arabia. It covers the timeline, deliverables and challenges as well as lessons learnt by the Project Team.

  18. A high-resolution map of the Nile tilapia genome: a resource for studying cichlids and other percomorphs

    Science.gov (United States)

    2012-01-01

    Background The Nile tilapia (Oreochromis niloticus) is the second most farmed fish species worldwide. It is also an important model for studies of fish physiology, particularly because of its broad tolerance to an array of environments. It is a good model to study evolutionary mechanisms in vertebrates, because of its close relationship to haplochromine cichlids, which have undergone rapid speciation in East Africa. The existing genomic resources for Nile tilapia include a genetic map, BAC end sequences and ESTs, but comparative genome analysis and maps of quantitative trait loci (QTL) are still limited. Results We have constructed a high-resolution radiation hybrid (RH) panel for the Nile tilapia and genotyped 1358 markers consisting of 850 genes, 82 markers corresponding to BAC end sequences, 154 microsatellites and 272 single nucleotide polymorphisms (SNPs). From these, 1296 markers could be associated in 81 RH groups, while 62 were not linked. The total size of the RH map is 34,084 cR3500 and 937,310 kb. It covers 88% of the entire genome with an estimated inter-marker distance of 742 Kb. Mapping of microsatellites enabled integration to the genetic map. We have merged LG8 and LG24 into a single linkage group, and confirmed that LG16-LG21 are also merged. The orientation and association of RH groups to each chromosome and LG was confirmed by chromosomal in situ hybridizations (FISH) of 55 BACs. Fifty RH groups were localized on the 22 chromosomes while 31 remained small orphan groups. Synteny relationships were determined between Nile tilapia, stickleback, medaka and pufferfish. Conclusion The RH map and associated FISH map provide a valuable gene-ordered resource for gene mapping and QTL studies. All genetic linkage groups with their corresponding RH groups now have a corresponding chromosome which can be identified in the karyotype. Placement of conserved segments indicated that multiple inter-chromosomal rearrangements have occurred between Nile tilapia

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

    Czech Academy of Sciences Publication Activity Database

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

    2016-01-01

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

  20. Electron paramagnetic resonance imaging of tumor hypoxia: enhanced spatial and temporal resolution for in vivo pO2 determination.

    Science.gov (United States)

    Matsumoto, Ken-ichiro; Subramanian, Sankaran; Devasahayam, Nallathamby; Aravalluvan, Thirumaran; Murugesan, Ramachandran; Cook, John A; Mitchell, James B; Krishna, Murali C

    2006-05-01

    The time-domain (TD) mode of electron paramagnetic resonance (EPR) data collection offers a means of estimating the concentration of a paramagnetic probe and the oxygen-dependent linewidth (LW) to generate pO2 maps with minimal errors. A methodology for noninvasive pO2 imaging based on the application of TD-EPR using oxygen-induced LW broadening of a triarylmethyl (TAM)-based radical is presented. The decay of pixel intensities in an image is used to estimate T2*, which is inversely proportional to pO2. Factors affecting T2* in each pixel are critically analyzed to extract the contribution of dissolved oxygen to EPR line-broadening. Suitable experimental and image-processing parameters were obtained to produce pO2 maps with minimal artifacts. Image artifacts were also minimized with the use of a novel data collection strategy using multiple gradients. Results from a phantom and in vivo imaging of tumor-bearing mice validated this novel method of noninvasive oximetry. The current imaging protocols achieve a spatial resolution of approximately 1.0 mm and a temporal resolution of approximately 9 s for 2D pO2 mapping, with a reliable oxygen resolution of approximately 1 mmHg (0.12% oxygen in gas phase). This work demonstrates that in vivo oximetry can be performed with good sensitivity, accuracy, and high spatial and temporal resolution.

  1. Information System of Resolution of Procedural Incidents and Management of the Modifications Made to the Electronic Court Registration

    Directory of Open Access Journals (Sweden)

    Ştefan Gheorghe PENTIUC

    2011-01-01

    Full Text Available This information system was made for its use by the staff responsible for random distribution of cases to the courts. The Information System of Resolution of Procedural Incidents and Management of the Modifications Made to the Electronic Court Registration consists of three new developed modules: the management module is a Web application which chronicles the modifications made in the electronic court registration, regarding the random assignment of cases,the resolution of procedural incidents, which is a Web service whose logic implements a logic Semantic Web application and the module of confirming judges which is a windows service running on the judges’ workstations. The Web service implements a Semantic Web application which processes the knowledgebase achieved through OWL ontology (Ontology Web Language by applying inferences leading to the correct solution. If this does not solve the problem, a set of associated Jena rules are used to infer and generate new knowledge. It also uses the SPARQL(SPARQL Protocol and RDF Query Language language that allows queries on the knowledge,similar to the classic query languages of databases. The novelty of the new conceived, designed and implemented system consists in accessing the domain knowledge as a web service to solve the procedural incidents occurred in electronic court registration.

  2. Resolution and Efficiency of Monitored Drift-Tube Chambers with Final Read-out Electronics at High Background Rates

    CERN Document Server

    Dubbert, J; Kortner, O; Kroha, H; Manz, A; Mohrdieck-Möck, S; Rauscher, F; Richter, R; Staude, A; Stiller, W

    2003-01-01

    The performance of a monitored drift-tube chamber for ATLAS with the final read-out electronics was tested at the Gamma Irradiation facility at CERN under varyin photon irradiation rates of up to 990~Hz\\,cm$^{-2}$ which corresponds to 10 times the highest background rate expected in ATLAS. The signal pulse-height measurement of the final read-out electronics was used to perform time-slewing corrections. The corrections improve the average single-tube resolution from 106~$\\mu$m to 89~$\\mu$m at the nominal discriminator threshold of 44~mV without irradiation, and from 114~$\\mu$m to 89~$\\mu$m at the maximum nominal irradiation rate in ATLAS of 100~Hz\\,cm$^{-2}$. The reduction of the threshold from 44~mV to 34~mV and the time-slewing corrections lead to an average single-tube resolution of 82~$\\mu$m without photon background and of 89~$\\mu$m at 100~Hz\\,cm$^{-2}$. The measured muon detection efficiency agrees with the expectation for the final read-out electronics.

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

    National Research Council Canada - National Science Library

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

    2005-01-01

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

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

    International Nuclear Information System (INIS)

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

    1977-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-02-15

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

  6. Composition measurement in substitutionally disordered materials by atomic resolution energy dispersive X-ray spectroscopy in scanning transmission electron microscopy.

    Science.gov (United States)

    Chen, Z; Taplin, D J; Weyland, M; Allen, L J; Findlay, S D

    2017-05-01

    The increasing use of energy dispersive X-ray spectroscopy in atomic resolution scanning transmission electron microscopy invites the question of whether its success in precision composition determination at lower magnifications can be replicated in the atomic resolution regime. In this paper, we explore, through simulation, the prospects for composition measurement via the model system of Al x Ga 1-x As, discussing the approximations used in the modelling, the variability in the signal due to changes in configuration at constant composition, and the ability to distinguish between different compositions. Results are presented in such a way that the number of X-ray counts, and thus the expected variation due to counting statistics, can be gauged for a range of operating conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Electronic tracking of human resource skills and knowledge, just in time training, manageable due diligence

    Energy Technology Data Exchange (ETDEWEB)

    Kolodziej, M.A. [Quick Test International Inc., (Canada). Canadian Technology Human Resource Board; Baker, O. [KeySpan Energy Canada, Calgary, AB (Canada)

    2001-06-01

    KeySpan Energy Canada is in the process of obtaining recognition of various occupational profiles including pipeline operators, inspectors, and field and plant operators from various certifying organizations. The process of allowing individuals to obtain certification is recognized by Canadian Technology Human Resources Board as a step towards national standards for technologists and technicians. Proven competency is a must for workers in todays oil industry in response to increasingly stringent government safety regulations, environmental concerns and high public scrutiny. Quick Test international Inc. has developed a management tool in collaboration with end users at KeySpan Energy Canada. It is an electronic, Internet based competency tool for tracking personal competencies and maintaining continued competency. Response to the tool has been favourable. 2 refs., 4 figs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1981-01-01

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  10. Characterisation of radiation damage in perovskite using high angular resolution electron channeling x-ray spectroscopy (HARECXS)

    International Nuclear Information System (INIS)

    Smith, K.L.; Zaluzec, N.J.

    2002-01-01

    Full text: Predicting and/or modelling the occurrence of radiation damage induced defects and their effects on physical properties (eg. amorphisation induced swelling, electrical conductivity., optical response etc.) in ceramic phases requires knowledge of the displacement energies, E d , of cations and anions in those phases. In this study, High Angular Resolution Electron Channelling X-ray Spectroscopy (HARECXS) spectra were collected from perovskite (CaTiO 3 ) samples that had been exposed to high-energy electrons or high-energy heavy ions. Calculations based on experimental data were then used to indicate the E d of the cations in perovskite. The HARECXS measurements were conducted on a Philips EM 420T AEM (LaB6 source, operated at 120 kV) fitted with an EDAX ultra thin window Si(Li) detector. The specimen was first manually oriented to an appropriate zone axis. Then control of the relative orientation of the incident probe was accomplished via direct computer control of the beam tilt coils, Typical acquisition times for a complete two-dimensional scan were 18-24 hours, while one dimensional scans ranged from 1-5 hours. Our experiments established that: a) HARECXS can detect radiation damage in perovskite caused by either high energy heavy ions or high energy electrons, b) the HARECXS signature of perovskite shows a systematic change with ion dose, c) HARECXS detects damage in perovskite that has been irradiated with 900kV electrons and does not detect damage in perovskite that has been irradiated with 620kV electrons, indicating the existance of an electron irradiation damage threshold. Calculations based on the latter results indicate that the displacement energy, E d of calcium and titanium in perovskite lie between 50 and 85eV. Copyright (2002) Australian Society for Electron Microscopy Inc

  11. Availability, Use and Constraints to Use of Electronic Information Resources by Postgraduates Students at the University of Ibadan

    Directory of Open Access Journals (Sweden)

    Dare Samuel Adeleke

    2017-12-01

    Full Text Available Availability, awareness and use of electronic resources provide access to authoritative, reliable, accurate and timely access to information. The use of electronic information resources (EIRs can enable innovation in teaching and increase timeliness in research of postgraduate students which will eventual result into encouragement of the expected research-led enquiry in this digital age. The study adopted a descriptive survey design. Samples of 300 of postgraduate students within seven out 13 Faculties were randomly selected. Data were collected using questionnaire designed to elicit response from respondents and data were analyzed using descriptive statistics methods percentages, mean, and standard deviation. Results indicated that internet was ranked most available and used in the university. Low level of usage of electronic resources, in particular, full texts data bases is linked to a number of constraints: Interrupted power supply was ranked highest among other factors as speed and capacity of computers, retrieval of records with high recall and low precision, retrieving records relevant to information need, lack of knowledge of search techniques to retrieve information effectively, non possession of requisite IT skills and problems accessing the internet. The study recommended that usage of electronic resources be made compulsory, intensifying awareness campaigns concerning the availability, training on use of electronic resources and the problem of power outage be addressed.

  12. Using mobile electronic devices to deliver educational resources in developing countries.

    Science.gov (United States)

    Mazal, Jonathan Robert; Ludwig, Rebecca

    2015-01-01

    Developing countries have far fewer trained radiography professionals than developed countries, which exacerbates the limited access to imaging services. The lack of trained radiographers reflects, in part, limited availability of radiographer-specific educational resources. Historically, organizations that provided such resources in the developing world faced challenges related to the limited stock of current materials as well as expenses associated with shipping and delivery. Four mobile electronic devices (MEDs) were loaded with educational content (e-books, PDFs, and digital applications) spanning major radiography topics. The MEDs were distributed to 4 imaging departments in Ghana, India, Nepal, and Nigeria based on evidence of need for radiography-specific resources, as revealed by survey responses. A cost comparison of postal delivery vs digital delivery of educational content was performed. The effectiveness of delivering additional content via Wi-Fi transmission also was evaluated. Feedback was solicited on users' experience with the MEDs as a delivery tool for educational content. An initial average per e-book expense of $30.05, which included the cost of the device, was calculated for the MED delivery method compared with $15.56 for postal delivery of printed materials. The cost of the MED delivery method was reduced to an average of $10.05 for subsequent e-book deliveries. Additional content was successfully delivered via Wi-Fi transmission to all recipients during the 3-month follow-up period. Overall user feedback on the experience was positive, and ideas for enhancing the MED-based method were identified. Using MEDs to deliver radiography-specific educational content appears to be more cost effective than postal delivery of printed materials on a long-term basis. MEDs are more efficient for providing updates to educational materials. Customization of content to department needs, and using projector devices could enhance the usefulness of MEDs for

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  14. The electronic encapsulation of knowledge in hydraulics, hydrology and water resources

    Science.gov (United States)

    Abbott, Michael B.

    The rapidly developing practice of encapsulating knowledge in electronic media is shown to lead necessarily to the restructuring of the knowledge itself. The consequences of this for hydraulics, hydrology and more general water-resources management are investigated in particular relation to current process-simulation, real-time control and advice-serving systems. The generic properties of the electronic knowledge encapsulator are described, and attention is drawn to the manner in which knowledge 'goes into hiding' through encapsulation. This property is traced in the simple situations of pure mathesis and in the more complex situations of taxinomia using one example each from hydraulics and hydrology. The consequences for systems architectures are explained, pointing to the need for multi-agent architectures for ecological modelling and for more general hydroinformatics systems also. The relevance of these developments is indicated by reference to ongoing projects in which they are currently being realised. In conclusion, some more general epistemological aspects are considered within the same context. As this contribution is so much concerned with the processes of signification and communication, it has been partly shaped by the theory of semiotics, as popularised by Eco ( A Theory of Semiotics, Indiana University, Bloomington, 1977).

  15. Plastics disassembly versus bulk recycling: engineering design for end-of-life electronics resource recovery.

    Science.gov (United States)

    Rios, Pedro; Stuart, Julie Ann; Grant, Ed

    2003-12-01

    Annual plastic flows through the business and consumer electronics manufacturing supply chain include nearly 3 billion lb of high-value engineering plastics derived from petroleum. The recovery of resource value from this stream presents critical challenges in areas of materials identification and recycling process design that demand new green engineering technologies applied together with life cycle assessment and ecological supply chain analysis to create viable plastics-to-plastics supply cycles. The sustainable recovery of potentially high-value engineering plastics streams requires that recyclers either avoid mixing plastic parts or purify later by separating smaller plastic pieces created in volume reduction (shredding) steps. Identification and separation constitute significant barriers in the plastics-to-plastics recycling value proposition. In the present work, we develop a model that accepts randomly arriving electronic products to study scenarios by which a recycler might identify and separate high-value engineering plastics as well as metals. Using discrete eventsimulation,we compare current mixed plastics recovery with spectrochemical plastic resin identification and subsequent sorting. Our results show that limited disassembly with whole-part identification can produce substantial yields in separated streams of recovered engineering thermoplastics. We find that disassembly with identification does not constitute a bottleneck, but rather, with relatively few workers, can be configured to pull the process and thus decrease maximum staging space requirements.

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

    International Nuclear Information System (INIS)

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

    2003-01-01

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

  17. Achievement of extreme resolution for the selective by depth Moessbauer method on conversion electrons

    International Nuclear Information System (INIS)

    Babenkov, M.I.; Zhdanov, V.S.; Ryzhikh, V.Yu.; Chubisov, M.A.

    2001-01-01

    At the Institute of Nuclear Physics of the National Nuclear Center of the Republic of Kazakhstan the depth selective conversion electrons Moessbauer spectroscopy (DSCEMS) method was realized on the facility designed on the magnet sector beta-spectrometer base with the dual focusing equipped with non-equipotential electron source in the multi-ribbon variant and the position-sensitive detector. In the work the model statistical calculations of energy and angular distributions experienced not so many times of inelastic scattering acts were carried out

  18. Spatial and temporal resolution in cryo-electron microscopy : a scope for nano-chemistry

    NARCIS (Netherlands)

    Frederik, P.M.; Sommerdijk, N.A.J.M.

    2005-01-01

    Cryo-electron microscopy has evolved in an established approach to study the structure of bio-colloids. Recent developments in instrumentation and automation, often demanded by life sciences, made cryo-EM a general tool in colloid chemistry. Recently improved instrumentation for vitrification has

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

    International Nuclear Information System (INIS)

    King, G.C.

    1986-01-01

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

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

    International Nuclear Information System (INIS)

    1988-01-01

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

  1. Towards a Resolution of the Proton Form Factor Problem: New Electron and Positron Scattering Data

    Science.gov (United States)

    Adikaram, D.; Rimal, D.; Weinstein, L. B.; Raue, B.; Khetarpal, P.; Bennett, R. P.; Arrington, J.; Brooks, W. K.; Adhikari, K. P.; Afanasev, A. V.; Amaryan, M. J.; Anderson, M. D.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Bono, J.; Boiarinov, S.; Briscoe, W. J.; Burkert, V. D.; Carman, D. S.; Careccia, S.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dodge, G. E.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Filippi, A.; Fleming, J. A.; Fradi, A.; Garillon, B.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guegan, B.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joo, K.; Joosten, S.; Kalantarians, N.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mattione, P.; Mayer, M.; McKinnon, B.; Mestayer, M. D.; Meyer, C. A.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moody, C. I.; Moutarde, H.; Movsisyan, A.; Camacho, C. Munoz; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Peña, C.; Pisano, S.; Pogorelko, O.; Price, J. W.; Procureur, S.; Prok, Y.; Protopopescu, D.; Puckett, A. J. R.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Simonyan, A.; Skorodumina, I.; Smith, E. S.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Stoler, P.; Strauch, S.; Sytnik, V.; Taiuti, M.; Tian, Ye; Trivedi, A.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

    2015-02-01

    There is a significant discrepancy between the values of the proton electric form factor, GEp, extracted using unpolarized and polarized electron scattering. Calculations predict that small two-photon exchange (TPE) contributions can significantly affect the extraction of GEp from the unpolarized electron-proton cross sections. We determined the TPE contribution by measuring the ratio of positron-proton to electron-proton elastic scattering cross sections using a simultaneous, tertiary electron-positron beam incident on a liquid hydrogen target and detecting the scattered particles in the Jefferson Lab CLAS detector. This novel technique allowed us to cover a wide range in virtual photon polarization (ɛ ) and momentum transfer (Q2) simultaneously, as well as to cancel luminosity-related systematic errors. The cross section ratio increases with decreasing ɛ at Q2=1.45 GeV2 . This measurement is consistent with the size of the form factor discrepancy at Q2≈1.75 GeV2 and with hadronic calculations including nucleon and Δ intermediate states, which have been shown to resolve the discrepancy up to 2 - 3 GeV2 .

  2. Technique for measuring hot plsma electron temperture by soft X-ray spectra with increased resolution

    International Nuclear Information System (INIS)

    Gulyaev, V.A.; Kabanovskij, S.V.; Lyadina, E.S.

    1985-01-01

    Ways of improving time resolution of amplitude spectrometers used for diagnostics of hot plasma in tokamaks are discussed. The circuit of an analog-to-digital processor for processing signals coming from detectors is suggested. The converter comprises 8 similar channels each of them including an input shaper, differential discriminator with a wide energy band; fast shaper with shaping time of 0.1-0.2 μs, analog delay circuit, linear transmission circuit, control device, slow shaping circuit, differential discriminator with a narrow energy band, digital intensimeter. Model test of the described channel is conducted; it confirmed correctness of the applied method

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

    Directory of Open Access Journals (Sweden)

    M. Salewski

    2017-08-01

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

  4. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-05-15

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

  6. Online diagnostics of time-resolved electron beam properties with femtosecond resolution for X-ray FELs

    International Nuclear Information System (INIS)

    Yan, Minjie

    2016-07-01

    The European X-ray Free-electron Laser (XFEL) puts high demands on the quality of the highbrightness driving electron beam with bunch lengths in the femtosecond regime. Longitudinal diagnostics is requested to optimize and control the longitudinal profile, the longitudinal phase space, the slice energy spread and the slice emittance of the electron bunch, all of which are crucial to the generation of Self-Amplified Spontaneous Emission (SASE). The high bunch repetition rate of the super-conducting accelerator renders diagnostic method that is (quasi) non-destructive to the generation of SASE possible. In this thesis, three online diagnostic sections utilizing transverse deflecting structures (TDS) have been designed for the European XFEL, providing access to all parameters of interest with a longitudinal resolution down to below 10 fs.The requirement on the non-destructive capability has been realized by the implementation of fast kickermagnets and off-axis screens, which has been validated experimentally using an installation of the same concept at the Free-electron Laser in Hamburg. A special slicing procedure has been developed to significantly enhance the accuracy of slice energy spread measurements. Suppression of coherence effects, which impede the beam imaging in the TDS diagnostics, has been first demonstrated experimentally using the spatial separation method with scintillator screens. Comparison of the results of emittance measurements using the quadrupole scan method with those using the multi-screen method has proved the reliability of the latter method, which has been modelled intensively for the European XFEL.

  7. Resolution-of-identity stochastic time-dependent configuration interaction for dissipative electron dynamics in strong fields.

    Science.gov (United States)

    Klinkusch, Stefan; Tremblay, Jean Christophe

    2016-05-14

    In this contribution, we introduce a method for simulating dissipative, ultrafast many-electron dynamics in intense laser fields. The method is based on the norm-conserving stochastic unraveling of the dissipative Liouville-von Neumann equation in its Lindblad form. The N-electron wave functions sampling the density matrix are represented in the basis of singly excited configuration state functions. The interaction with an external laser field is treated variationally and the response of the electronic density is included to all orders in this basis. The coupling to an external environment is included via relaxation operators inducing transition between the configuration state functions. Single electron ionization is represented by irreversible transition operators from the ionizing states to an auxiliary continuum state. The method finds its efficiency in the representation of the operators in the interaction picture, where the resolution-of-identity is used to reduce the size of the Hamiltonian eigenstate basis. The zeroth-order eigenstates can be obtained either at the configuration interaction singles level or from a time-dependent density functional theory reference calculation. The latter offers an alternative to explicitly time-dependent density functional theory which has the advantage of remaining strictly valid for strong field excitations while improving the description of the correlation as compared to configuration interaction singles. The method is tested on a well-characterized toy system, the excitation of the low-lying charge transfer state in LiCN.

  8. Resolution-of-identity stochastic time-dependent configuration interaction for dissipative electron dynamics in strong fields

    Energy Technology Data Exchange (ETDEWEB)

    Klinkusch, Stefan; Tremblay, Jean Christophe [Institute for Chemistry and Biochemistry, Freie Universität Berlin, Takustr. 3, D-14195 Berlin (Germany)

    2016-05-14

    In this contribution, we introduce a method for simulating dissipative, ultrafast many-electron dynamics in intense laser fields. The method is based on the norm-conserving stochastic unraveling of the dissipative Liouville-von Neumann equation in its Lindblad form. The N-electron wave functions sampling the density matrix are represented in the basis of singly excited configuration state functions. The interaction with an external laser field is treated variationally and the response of the electronic density is included to all orders in this basis. The coupling to an external environment is included via relaxation operators inducing transition between the configuration state functions. Single electron ionization is represented by irreversible transition operators from the ionizing states to an auxiliary continuum state. The method finds its efficiency in the representation of the operators in the interaction picture, where the resolution-of-identity is used to reduce the size of the Hamiltonian eigenstate basis. The zeroth-order eigenstates can be obtained either at the configuration interaction singles level or from a time-dependent density functional theory reference calculation. The latter offers an alternative to explicitly time-dependent density functional theory which has the advantage of remaining strictly valid for strong field excitations while improving the description of the correlation as compared to configuration interaction singles. The method is tested on a well-characterized toy system, the excitation of the low-lying charge transfer state in LiCN.

  9. SAGES: a suite of freely-available software tools for electronic disease surveillance in resource-limited settings.

    Directory of Open Access Journals (Sweden)

    Sheri L Lewis

    Full Text Available Public health surveillance is undergoing a revolution driven by advances in the field of information technology. Many countries have experienced vast improvements in the collection, ingestion, analysis, visualization, and dissemination of public health data. Resource-limited countries have lagged behind due to challenges in information technology infrastructure, public health resources, and the costs of proprietary software. The Suite for Automated Global Electronic bioSurveillance (SAGES is a collection of modular, flexible, freely-available software tools for electronic disease surveillance in resource-limited settings. One or more SAGES tools may be used in concert with existing surveillance applications or the SAGES tools may be used en masse for an end-to-end biosurveillance capability. This flexibility allows for the development of an inexpensive, customized, and sustainable disease surveillance system. The ability to rapidly assess anomalous disease activity may lead to more efficient use of limited resources and better compliance with World Health Organization International Health Regulations.

  10. Improving the resolution in soft X-ray emission spectrometers through photon-counting using an Electron Multiplying CCD

    International Nuclear Information System (INIS)

    Hall, D J; Soman, M; Tutt, J; Murray, N; Holland, A; Schmitt, T; Raabe, J; Strocov, V N; Schmitt, B

    2012-01-01

    In 2007, a study of back-illuminated Charge-Coupled Devices (CCDs) for soft X-ray photon detection demonstrated the improvements that could be brought over more traditional micro-channel plate detectors for X-ray spectrometers based on diffraction gratings and position sensitive detectors. Whilst the spatial resolution was reported to be improved dramatically, an intrinsic limit of approximately 25 micrometers was found due to the spreading of the charge cloud generated in the CCD across several pixels. To overcome this resolution limit, it is necessary to move away from the current integrated imaging methods and consider a photon-counting approach, recording the photon interaction locations to the sub-pixel level. To make use of photon-counting techniques it is important that the individual events are separable. To maintain the throughput of the spectrometer for high intensity lines, higher frame rates and therefore higher readout speeds are required. With CCD based systems, the increased noise at high readout speeds can limit the photon-counting performance. The Electron-Multiplying CCD shares a similar architecture with the standard CCD but incorporates a g ain register . This novel addition allows controllable gain to be applied to the signal before the read noise is introduced, therefore allowing individual events to be resolved above the noise even at much higher readout rates. In the past, the EM-CCD has only been available with imaging areas too small to be practical in soft X-ray emission spectrometers. The current drive for large area Electron-Multiplying CCDs is opening this technology to new photon-counting applications, requiring in-depth analysis of the processes and techniques involved. Early results indicate that through the introduction of photon-counting techniques the resolution in such systems can be dramatically improved.

  11. Sensitivity and spatial resolution for electron-spin-resonance detection by magnetic resonance force microscopy

    International Nuclear Information System (INIS)

    Zhang, Z.; Roukes, M.L.; Hammel, P.C.

    1996-01-01

    The signal intensity of electron spin resonance in magnetic resonance force microscopy (MRFM) experiments employing periodic saturation of the electron spin magnetization is determined by four parameters: the rf field H 1 , the modulation level of the bias field H m , the spin relaxation time τ 1 , and the magnetic size R(∂H/∂z) of the sample. Calculations of the MRFM spectra obtained from a 2,2-diphenyl-1-picrylhydrazyl particle have been performed for various conditions. The results are compared with experimental data and excellent agreement is found. The systematic variation of the signal intensity as a function of H 1 and H m provides a powerful tool to characterize the MRFM apparatus. copyright 1996 American Institute of Physics

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

    International Nuclear Information System (INIS)

    Blok, H.

    1986-01-01

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

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

    International Nuclear Information System (INIS)

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

    2003-01-01

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

  14. Optical Sideband Generation: a Longitudinal Electron Beam Diagnostic Beyond the Laser Bandwidth Resolution Limit

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence Berkeley National Laboratory; Tilborg, J. van; Matlis, N. H.; Plateau, G. R.; Leemans, W. P.

    2010-06-01

    Electro-optic sampling (EOS) is widely used as a technique to measure THz-domain electric field pulses such asthe self-fields of femtosecond electron beams. We present an EOS-based approach for single-shot spectral measurement that excels in simplicity (compatible with fiber integration) and bandwidth coverage (overcomes the laser bandwidth limitation), allowing few-fs electron beams or single-cycle THz pulses to be characterized with conventional picosecond probes. It is shown that the EOS-induced optical sidebands on the narrow-bandwidth optical probe are spectrally-shifted replicas of the THz pulse. An experimental demonstration on a 0-3 THz source is presented.

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

    International Nuclear Information System (INIS)

    Borisenko, Konstantin B; Kirkland, Angus I

    2014-01-01

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

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

    International Nuclear Information System (INIS)

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

    1977-11-01

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

  17. Electronic Human Resources Management (e-HRM Adoption Studies: Past and Future Research

    Directory of Open Access Journals (Sweden)

    Winarto Winarto

    2018-05-01

    Full Text Available Electronic human resource management (e-HRM systems become more widely used by profit and non-profit organization. However, the field currently lacks sound theoretical frameworks that can be useful in addressing a key issue concerning the implementation of e-HRM systems, in particular to obtain a better understanding of the factors influencing the adoption of e-HRM systems. The objective of this paper is to provide a foundation towards the development of a theoretical framework for the implementation of e-HRM systems and develop a conceptual model that would reflect the nature of e-HRM systems’ adoption through systematic literature review. Adopting Crossan and Apaydin’s procedure of systematic review, this paper investigated 21 empirical papers of electronics human resources management, then categorized them into 4 characteristics which influence the adoption; System and technology characteristics; Organizational characteristics; User/individual characteristics, and Environmental and contextual characteristics. Finally, the e-HRM adoption research framework is drawn and based on the framework; avenues for future research are discussed.   Bahasa Indonesia Abstrak: Manajemen sumber daya manusia elektronik (selanjutnya disebut dengan e-HRM semakin banyak digunakan oleh organisasi profit dan nonprofit. Namun, bidang dan topik ini belum memiliki kerangka teori yang mapan, yang dapat digunakan untuk menganalisis isu-isu terkait penerapan e-HRM, terutama mengenai faktor-faktor yang mempengaruhi adopsi sistem e-HRM. Tujuan penelitian ini adalah untuk memberikan landasan bagi pengembangan kerangka teoritis untuk implementasi sistem e-HRM dan mengembangkan model konseptual yang akan menggambarkan adopsi sistem e-HRM melalui tinjauan literatur sistematis. Mengadopsi prosedur dan metode Crossan dan Apaydin untuk melakukan telaah literatur secara sistematis, paper ini menyelidiki 21 publikasi empiris manajemen sumber daya manusia elektronik dari 2

  18. Precision and resolution on Tore-Supra ECE electron temperature profile measurements

    International Nuclear Information System (INIS)

    Segui, J.L.; Molina, D.; Goniche, M.

    2003-01-01

    A 16-channel heterodyne radiometer, 2 GHz spaced, is used on Tore-Supra to measure the electron cyclotron emission in the frequency range 78-110 GHz for the O mode and 94 -126 GHz for the X mode. In the equatorial plane, a dual polarisation Gaussian optics lens antenna, with a perpendicular line of sight (with respect to the magnetic field), gives ECE measurements with very low refraction and Doppler effects. A separate O/X mode RF front-end allows the use of an IF electronic mode selector. This improves time stability calibration and gives the potentiality of simultaneous O/X mode measurements in the 94 -110 GHz RF band for polarisation studies. RF and IF filters reject the gyrotron frequency (118 GHz) in order to perform temperature measurements during ECRH plasmas. A precise absolute spectral calibration is performed outside the vacuum vessel by using a 600 deg. C black body, a digital signal averaging on the waveform generated by a mechanical chopper placed directly in front of it, and a simulation window without Fabry-Perot effects. The calibration precision leads to ECE temperature profiles which are very consistent with Thomson scattering measurements and guarantees a good stability of the ECE profiles for small changes on the magnetic field (absolute precision ± 6%, relative precision between channels ± 3%). Post-pulse data processing takes routinely into account the total magnetic field (B vacuum with ripple, B para , B dia , B pol , all with analytical formulations), the radial relativistic shift (analytical formulation is used), the refraction, not described in this paper, (cut-off detection with safety margin to avoid strong refraction), the nonthermal ECE spectra, not described in this paper, during LHCD (using an electron density threshold criterion). These previous analytical formulations are compatible with real time processing. Relativistic radial broadening simulations show that it is useful to fulfill 32 channels (1 GHz spaced). (authors)

  19. Precision and resolution on Tore-Supra ECE electron temperature profile measurements

    Energy Technology Data Exchange (ETDEWEB)

    Segui, J.L.; Molina, D.; Goniche, M. [Association EURATOM -CEA, CEA/DSM/DRFC CEA-Cadarache, 13108 St Paul-lez-Durance (France)

    2003-07-01

    A 16-channel heterodyne radiometer, 2 GHz spaced, is used on Tore-Supra to measure the electron cyclotron emission in the frequency range 78-110 GHz for the O mode and 94 -126 GHz for the X mode. In the equatorial plane, a dual polarisation Gaussian optics lens antenna, with a perpendicular line of sight (with respect to the magnetic field), gives ECE measurements with very low refraction and Doppler effects. A separate O/X mode RF front-end allows the use of an IF electronic mode selector. This improves time stability calibration and gives the potentiality of simultaneous O/X mode measurements in the 94 -110 GHz RF band for polarisation studies. RF and IF filters reject the gyrotron frequency (118 GHz) in order to perform temperature measurements during ECRH plasmas. A precise absolute spectral calibration is performed outside the vacuum vessel by using a 600 deg. C black body, a digital signal averaging on the waveform generated by a mechanical chopper placed directly in front of it, and a simulation window without Fabry-Perot effects. The calibration precision leads to ECE temperature profiles which are very consistent with Thomson scattering measurements and guarantees a good stability of the ECE profiles for small changes on the magnetic field (absolute precision {+-} 6%, relative precision between channels {+-} 3%). Post-pulse data processing takes routinely into account the total magnetic field (B{sub vacuum} with ripple, B{sub para}, B{sub dia}, B{sub pol}, all with analytical formulations), the radial relativistic shift (analytical formulation is used), the refraction, not described in this paper, (cut-off detection with safety margin to avoid strong refraction), the nonthermal ECE spectra, not described in this paper, during LHCD (using an electron density threshold criterion). These previous analytical formulations are compatible with real time processing. Relativistic radial broadening simulations show that it is useful to fulfill 32 channels (1 GHz

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

    Science.gov (United States)

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

    1995-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Guillaume Ducournau

    2009-11-01

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

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

    Science.gov (United States)

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

    2009-01-01

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

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

    Science.gov (United States)

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

    2009-01-01

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

  4. Sub-nanometre resolution of atomic motion during electronic excitation in phase-change materials.

    Science.gov (United States)

    Mitrofanov, Kirill V; Fons, Paul; Makino, Kotaro; Terashima, Ryo; Shimada, Toru; Kolobov, Alexander V; Tominaga, Junji; Bragaglia, Valeria; Giussani, Alessandro; Calarco, Raffaella; Riechert, Henning; Sato, Takahiro; Katayama, Tetsuo; Ogawa, Kanade; Togashi, Tadashi; Yabashi, Makina; Wall, Simon; Brewe, Dale; Hase, Muneaki

    2016-02-12

    Phase-change materials based on Ge-Sb-Te alloys are widely used in industrial applications such as nonvolatile memories, but reaction pathways for crystalline-to-amorphous phase-change on picosecond timescales remain unknown. Femtosecond laser excitation and an ultrashort x-ray probe is used to show the temporal separation of electronic and thermal effects in a long-lived (>100 ps) transient metastable state of Ge2Sb2Te5 with muted interatomic interaction induced by a weakening of resonant bonding. Due to a specific electronic state, the lattice undergoes a reversible nondestructive modification over a nanoscale region, remaining cold for 4 ps. An independent time-resolved x-ray absorption fine structure experiment confirms the existence of an intermediate state with disordered bonds. This newly unveiled effect allows the utilization of non-thermal ultra-fast pathways enabling artificial manipulation of the switching process, ultimately leading to a redefined speed limit, and improved energy efficiency and reliability of phase-change memory technologies.

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

    Directory of Open Access Journals (Sweden)

    H Ichinose

    2000-01-01

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

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

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  7. Resolution of the hydroxyapatite crystal lattice in bone and dental enamel by electron microscopy

    International Nuclear Information System (INIS)

    Selvig, K.A.

    1975-01-01

    The molecular and atomic structure of hydroxyapatite was studied by transmission electron microscopy. The form, size and packing of hydroxyapatite crystals in sections of bone and dental hard tissues could be determined. Lattice fringe patterns with repeat distances in the range 2.7-8.2 A occurred in images of individual crystals. On the basis of these fringes the true orientation of the crystals relative to the plane of sectioning was calculated. The observed crystal lattice spacings and interplanar angles were in close agreement with data derived from X-ray diffraction analysis. This study shows that the possibility exists of relating crystallographic analysis to the morphology and fine structure of calcified tissue in health and disease

  8. Band resolution of optical spectra of solvated electrons in water, alcohols, and tetrahydrofuran

    International Nuclear Information System (INIS)

    Jou, F.-Y.; Freeman, G.R.

    1979-01-01

    The optical absorption spectra of solvated electrons in water, alcohols, and tetrahydrofuran are empirically resolved into two Gaussian bands and a continuum tail. The first Gaussian band covers most of the low energy side of the spectrum. The second Gaussian band lies at an energy slightly above that of the absorption maximum of the total spectrum. With the exception of tert-butyl alcohol, in water and alcohols the following were observed: (a) the first Gaussian bands have the same half-width, but the oscillator strength in water is about double that in an alcohol; (b) the second Gaussian bands have similar half-widths and oscillator strengths; (c) the continuum tails have similar half-widths, yet that in water possesses only about one third as much oscillator strength as the one in alcohol. In tert-butyl alcohol and tetrahydrofuran the first Gaussian band and the continuum tail each carry nearly half of the total oscillator strength. (author)

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

    Science.gov (United States)

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

    2017-08-03

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

  10. Tensor decompositions for the analysis of atomic resolution electron energy loss spectra

    Energy Technology Data Exchange (ETDEWEB)

    Spiegelberg, Jakob; Rusz, Ján [Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala (Sweden); Pelckmans, Kristiaan [Department of Information Technology, Uppsala University, Box 337, S-751 05 Uppsala (Sweden)

    2017-04-15

    A selection of tensor decomposition techniques is presented for the detection of weak signals in electron energy loss spectroscopy (EELS) data. The focus of the analysis lies on the correct representation of the simulated spatial structure. An analysis scheme for EEL spectra combining two-dimensional and n-way decomposition methods is proposed. In particular, the performance of robust principal component analysis (ROBPCA), Tucker Decompositions using orthogonality constraints (Multilinear Singular Value Decomposition (MLSVD)) and Tucker decomposition without imposed constraints, canonical polyadic decomposition (CPD) and block term decompositions (BTD) on synthetic as well as experimental data is examined. - Highlights: • A scheme for compression and analysis of EELS or EDX data is proposed. • Several tensor decomposition techniques are presented for BSS on hyperspectral data. • Robust PCA and MLSVD are discussed for denoising of raw data.

  11. Impact of Electronic Resources and Usage in Academic Libraries in Ghana: Evidence from Koforidua Polytechnic & All Nations University College, Ghana

    Science.gov (United States)

    Akussah, Maxwell; Asante, Edward; Adu-Sarkodee, Rosemary

    2015-01-01

    The study investigates the relationship between impact of electronic resources and its usage in academic libraries in Ghana: evidence from Koforidua Polytechnic & All Nations University College, Ghana. The study was a quantitative approach using questionnaire to gather data and information. A valid response rate of 58.5% was assumed. SPSS…

  12. Utilization of Electronic Information Resources by Undergraduate Students of University of Ibadan: A Case Study of Social Sciences and Education

    Science.gov (United States)

    Owolabi, Sola; Idowu, Oluwafemi A.; Okocha, Foluke; Ogundare, Atinuke Omotayo

    2016-01-01

    The study evaluated utilization of electronic information resources by undergraduates in the Faculties of Education and the Social Sciences in University of Ibadan. The study adopted a descriptive survey design with a study population of 1872 undergraduates in the Faculties of Education and the Social Sciences in University of Ibadan, from which a…

  13. Crocus sativus Petals: Waste or Valuable Resource? The Answer of High-Resolution and High-Resolution Magic Angle Spinning Nuclear Magnetic Resonance.

    Science.gov (United States)

    Righi, Valeria; Parenti, Francesca; Tugnoli, Vitaliano; Schenetti, Luisa; Mucci, Adele

    2015-09-30

    Intact Crocus sativus petals were studied for the first time by high-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy, revealing the presence of kinsenoside (2) and goodyeroside A (3), together with 3-hydroxy-γ-butyrolactone (4). These findings were confirmed by HR-NMR analysis of the ethanol extract of fresh petals and showed that, even though carried out rapidly, partial hydrolysis of glucopyranosyloxybutanolides occurs during extraction. On the other hand, kaempferol 3-O-sophoroside (1), which is "NMR-silent" in intact petals, is present in extracts. These results suggest to evaluate the utilization of saffron petals for phytopharmaceutical and nutraceutical purposes to exploit a waste product of massive production of commercial saffron and point to the application of HR-MAS NMR for monitoring bioactive compounds directly on intact petals, avoiding the extraction procedure and the consequent hydrolysis reaction.

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

    International Nuclear Information System (INIS)

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

    1986-01-01

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

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

    International Nuclear Information System (INIS)

    Hewat, E.A.

    1988-01-01

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

  16. Structure and orbital ordering of ultrathin LaVO{sub 3} probed by atomic resolution electron microscopy and Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lindfors-Vrejoiu, Ionela; Engelmayer, Johannes; Loosdrecht, Paul H.M. van [II. Physikalisches Institut, Koeln Univ. (Germany); Jin, Lei; Jia, Chun-Lin [Peter Gruenberg Institut (PGI-5) and Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Juelich GmbH (Germany); Himcinschi, Cameliu [Institut fuer Theoretische Physik, TU Bergakademie Freiberg (Germany); Hensling, Felix; Waser, Rainer; Dittmann, Regina [Peter Gruenberg Institut (PGI-7), Forschungszentrum Juelich GmbH (Germany)

    2017-03-15

    Orbital ordering has been less investigated in epitaxial thin films, due to the difficulty to evidence directly the occurrence of this phenomenon in thin film samples. Atomic resolution electron microscopy enabled us to observe the structural details of the ultrathin LaVO{sub 3} films. The transition to orbital ordering of epitaxial layers as thin as ∼4 nm was probed by temperature-dependent Raman scattering spectroscopy of multilayer samples. From the occurrence and temperature dependence of the 700 cm{sup -1} Raman active mode it can be inferred that the structural phase transition associated with orbital ordering takes place in ultrathin LaVO{sub 3} films at about 130 K. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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

    International Nuclear Information System (INIS)

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

    1989-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1989-06-01

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

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

    Science.gov (United States)

    Hunter, Ryan C; Beveridge, Terry J

    2005-11-01

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

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

    Science.gov (United States)

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

    2018-06-01

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

  1. Systematic review of electronic surveillance of infectious diseases with emphasis on antimicrobial resistance surveillance in resource-limited settings.

    Science.gov (United States)

    Rattanaumpawan, Pinyo; Boonyasiri, Adhiratha; Vong, Sirenda; Thamlikitkul, Visanu

    2018-02-01

    Electronic surveillance of infectious diseases involves rapidly collecting, collating, and analyzing vast amounts of data from interrelated multiple databases. Although many developed countries have invested in electronic surveillance for infectious diseases, the system still presents a challenge for resource-limited health care settings. We conducted a systematic review by performing a comprehensive literature search on MEDLINE (January 2000-December 2015) to identify studies relevant to electronic surveillance of infectious diseases. Study characteristics and results were extracted and systematically reviewed by 3 infectious disease physicians. A total of 110 studies were included. Most surveillance systems were developed and implemented in high-income countries; less than one-quarter were conducted in low-or middle-income countries. Information technologies can be used to facilitate the process of obtaining laboratory, clinical, and pharmacologic data for the surveillance of infectious diseases, including antimicrobial resistance (AMR) infections. These novel systems require greater resources; however, we found that using electronic surveillance systems could result in shorter times to detect targeted infectious diseases and improvement of data collection. This study highlights a lack of resources in areas where an effective, rapid surveillance system is most needed. The availability of information technology for the electronic surveillance of infectious diseases, including AMR infections, will facilitate the prevention and containment of such emerging infectious diseases. Copyright © 2018 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  3. Optimizing low-light microscopy with back-illuminated electron multiplying charge-coupled device: enhanced sensitivity, speed, and resolution.

    Science.gov (United States)

    Coates, Colin G; Denvir, Donal J; McHale, Noel G; Thornbury, Keith D; Hollywood, Mark A

    2004-01-01

    The back-illuminated electron multiplying charge-coupled device (EMCCD) camera is having a profound influence on the field of low-light dynamic cellular microscopy, combining highest possible photon collection efficiency with the ability to virtually eliminate the readout noise detection limit. We report here the use of this camera, in 512 x 512 frame-transfer chip format at 10-MHz pixel readout speed, in optimizing a demanding ultra-low-light intracellular calcium flux microscopy setup. The arrangement employed includes a spinning confocal Nipkow disk, which, while facilitating the need to both generate images at very rapid frame rates and minimize background photons, yields very weak signals. The challenge for the camera lies not just in detecting as many of these scarce photons as possible, but also in operating at a frame rate that meets the temporal resolution requirements of many low-light microscopy approaches, a particular demand of smooth muscle calcium flux microscopy. Results presented illustrate both the significant sensitivity improvement offered by this technology over the previous standard in ultra-low-light CCD detection, the GenIII+intensified charge-coupled device (ICCD), and also portray the advanced temporal and spatial resolution capabilities of the EMCCD. Copyright 2004 Society of Photo-Optical Instrumentation Engineers.

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

    Science.gov (United States)

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

    1995-01-01

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

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

    Science.gov (United States)

    Heinemann, K.

    1985-01-01

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

  6. Atomic Resolution Structures of Human Bufaviruses Determined by Cryo-Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Maria Ilyas

    2018-01-01

    Full Text Available Bufavirus strain 1 (BuV1, a member of the Protoparvovirus genus of the Parvoviridae, was first isolated from fecal samples of children with acute diarrhea in Burkina Faso. Since this initial discovery, BuVs have been isolated in several countries, including Finland, the Netherlands, and Bhutan, in pediatric patients exhibiting similar symptoms. Towards their characterization, the structures of virus-like particles of BuV1, BuV2, and BuV3, the current known genotypes, have been determined by cryo-electron microscopy and image reconstruction to 2.84, 3.79, and 3.25 Å, respectively. The BuVs, 65–73% identical in amino acid sequence, conserve the major viral protein, VP2, structure and general capsid surface features of parvoviruses. These include a core β-barrel (βB-βI, α-helix A, and large surface loops inserted between these elements in VP2. The capsid contains depressions at the icosahedral 2-fold and around the 5-fold axes, and has three separated protrusions surrounding the 3-fold axes. Structure comparison among the BuVs and to available parvovirus structures revealed capsid surface variations and capsid 3-fold protrusions that depart from the single pinwheel arrangement of the animal protoparvoviruses. These structures provide a platform to begin the molecular characterization of these potentially pathogenic viruses.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-04-15

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

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

    NARCIS (Netherlands)

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

    2002-01-01

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

  9. The Use of Electronic Resources by Academic Staff at the University of Ilorin, Nigeria

    Science.gov (United States)

    Tella, Adeyinka; Orim, Faith; Ibrahim, Dauda Morenikeji; Memudu, Suleiman Ajala

    2018-01-01

    The use of e-resources is now commonplace among academics in tertiary educational institutions the world over. Many academics including those in the universities are exploring the opportunities of e-resources to facilitate teaching and research. As the use of e-resources is increasing particularly among academics at the University of Ilorin,…

  10. Modeling antecedents of electronic medical record system implementation success in low-resource setting hospitals.

    Science.gov (United States)

    Tilahun, Binyam; Fritz, Fleur

    2015-08-01

    With the increasing implementation of Electronic Medical Record Systems (EMR) in developing countries, there is a growing need to identify antecedents of EMR success to measure and predict the level of adoption before costly implementation. However, less evidence is available about EMR success in the context of low-resource setting implementations. Therefore, this study aims to fill this gap by examining the constructs and relationships of the widely used DeLone and MacLean (D&M) information system success model to determine whether it can be applied to measure EMR success in those settings. A quantitative cross sectional study design using self-administered questionnaires was used to collect data from 384 health professionals working in five governmental hospitals in Ethiopia. The hospitals use a comprehensive EMR system since three years. Descriptive and structural equation modeling methods were applied to describe and validate the extent of relationship of constructs and mediating effects. The findings of the structural equation modeling shows that system quality has significant influence on EMR use (β = 0.32, P quality has significant influence on EMR use (β = 0.44, P service quality has strong significant influence on EMR use (β = 0.36, P effect of EMR use on user satisfaction was not significant. Both EMR use and user satisfaction have significant influence on perceived net-benefit (β = 0.31, P mediating factor in the relationship between service quality and EMR use (P effect on perceived net-benefit of health professionals. EMR implementers and managers in developing countries are in urgent need of implementation models to design proper implementation strategies. In this study, the constructs and relationships depicted in the updated D&M model were found to be applicable to assess the success of EMR in low resource settings. Additionally, computer literacy was found to be a mediating factor in EMR use and user satisfaction of

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

    International Nuclear Information System (INIS)

    Putaux, Jean-Luc

    1991-01-01

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

  12. High-spatial-resolution electron density measurement by Langmuir probe for multi-point observations using tiny spacecraft

    Science.gov (United States)

    Hoang, H.; Røed, K.; Bekkeng, T. A.; Trondsen, E.; Clausen, L. B. N.; Miloch, W. J.; Moen, J. I.

    2017-11-01

    A method for evaluating electron density using a single fixed-bias Langmuir probe is presented. The technique allows for high-spatio-temporal resolution electron density measurements, which can be effectively carried out by tiny spacecraft for multi-point observations in the ionosphere. The results are compared with the multi-needle Langmuir probe system, which is a scientific instrument developed at the University of Oslo comprising four fixed-bias cylindrical probes that allow small-scale plasma density structures to be characterized in the ionosphere. The technique proposed in this paper can comply with the requirements of future small-sized spacecraft, where the cost-effectiveness, limited space available on the craft, low power consumption and capacity for data-links need to be addressed. The first experimental results in both the plasma laboratory and space confirm the efficiency of the new approach. Moreover, detailed analyses on two challenging issues when deploying the DC Langmuir probe on a tiny spacecraft, which are the limited conductive area of the spacecraft and probe surface contamination, are presented in the paper. It is demonstrated that the limited conductive area, depending on applications, can either be of no concern for the experiment or can be resolved by mitigation methods. Surface contamination has a small impact on the performance of the developed probe.

  13. StatSTEM: An efficient approach for accurate and precise model-based quantification of atomic resolution electron microscopy images

    Energy Technology Data Exchange (ETDEWEB)

    De Backer, A.; Bos, K.H.W. van den [Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Van den Broek, W. [AG Strukturforschung/Elektronenmikroskopie, Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, 12489 Berlin (Germany); Sijbers, J. [iMinds-Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Van Aert, S., E-mail: sandra.vanaert@uantwerpen.be [Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium)

    2016-12-15

    An efficient model-based estimation algorithm is introduced to quantify the atomic column positions and intensities from atomic resolution (scanning) transmission electron microscopy ((S)TEM) images. This algorithm uses the least squares estimator on image segments containing individual columns fully accounting for overlap between neighbouring columns, enabling the analysis of a large field of view. For this algorithm, the accuracy and precision with which measurements for the atomic column positions and scattering cross-sections from annular dark field (ADF) STEM images can be estimated, has been investigated. The highest attainable precision is reached even for low dose images. Furthermore, the advantages of the model-based approach taking into account overlap between neighbouring columns are highlighted. This is done for the estimation of the distance between two neighbouring columns as a function of their distance and for the estimation of the scattering cross-section which is compared to the integrated intensity from a Voronoi cell. To provide end-users this well-established quantification method, a user friendly program, StatSTEM, is developed which is freely available under a GNU public license. - Highlights: • An efficient model-based method for quantitative electron microscopy is introduced. • Images are modelled as a superposition of 2D Gaussian peaks. • Overlap between neighbouring columns is taken into account. • Structure parameters can be obtained with the highest precision and accuracy. • StatSTEM, auser friendly program (GNU public license) is developed.

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

    Science.gov (United States)

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

    1989-10-01

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

  15. An Inexpensive High-Temporal Resolution Electronic Sun Journal for Monitoring Personal Day to Day Sun Exposure Patterns

    Directory of Open Access Journals (Sweden)

    Nathan J. Downs

    2017-11-01

    Full Text Available Exposure to natural sunlight, specifically solar ultraviolet (UV radiation contributes to lifetime risks of skin cancer, eye disease, and diseases associated with vitamin D insufficiency. Improved knowledge of personal sun exposure patterns can inform public health policy; and help target high-risk population groups. Subsequently, an extensive number of studies have been conducted to measure personal solar UV exposure in a variety of settings. Many of these studies, however, use digital or paper-based journals (self-reported volunteer recall, or employ cost prohibitive electronic UV dosimeters (that limit the size of sample populations, to estimate periods of exposure. A cost effective personal electronic sun journal (ESJ built from readily available infrared photodiodes is presented in this research. The ESJ can be used to complement traditional UV dosimeters that measure total biologically effective exposure by providing a time-stamped sun exposure record. The ESJ can be easily attached to clothing and data logged to personal devices (including fitness monitors or smartphones. The ESJ improves upon self-reported exposure recording and is a cost effective high-temporal resolution option for monitoring personal sun exposure behavior in large population studies.

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

    International Nuclear Information System (INIS)

    Woods, J.P.

    1986-01-01

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

  17. Use and Cost of Electronic Resources in Central Library of Ferdowsi University Based on E-metrics

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Davarpanah

    2012-07-01

    Full Text Available The purpose of this study was to investigate the usage of electronic journals in Ferdowsi University, Iran based on e-metrics. The paper also aimed to emphasize the analysis of cost-benefit and the correlation between the journal impact factors and the usage data. In this study experiences of Ferdowsi University library on licensing and usage of electronic resources was evaluated by providing a cost-benefit analysis based on the cost and usage statistics of electronic resources. Vendor-provided data were also compared with local usage data. The usage data were collected by tracking web-based access locally, and by collecting vender-provided usage data. The data sources were one-year of vendor-supplied e-resource usage data such as Ebsco, Elsevier, Proquest, Emerald, Oxford and Springer and local usage data collected from the Ferdowsi university web server. The study found that actual usage values differ for vendor-provided data and local usage data. Elsevier has got the highest usage degree in searches, sessions and downloads. Statistics also showed that a small number of journals satisfy significant amount of use while the majority of journals were used less frequent and some were never used at all. The users preferred the PDF rather than HTML format. The data in subject profile suggested that the provided e-resources were best suited to certain subjects. There was no correlation between IF and electronic journal use. Monitoring the usage of e-resources gained increasing importance for acquisition policy and budget decisions. The article provided information about local metrics for the six surveyed vendors/publishers, e.g. usage trends, requests per package, cost per use as related to the scientific specialty of the university.

  18. Water Resource Management Mechanisms for Intrastate Violent Conflict Resolution: the Capacity Gap and What To Do About It.

    Science.gov (United States)

    Workman, M.; Veilleux, J. C.

    2014-12-01

    Violent conflict and issues surrounding available water resources are both global problems and are connected. Violent conflict is increasingly intrastate in nature and coupled with increased hydrological variability as a function of climate change, there will be increased pressures on water resource use. The majority of mechanisms designed to secure water resources are often based on the presence of a governance framework or another type of institutional capacity, such as offered through a supra- or sub-national organization like the United Nations or a river basin organization. However, institutional frameworks are not present or loose functionality during violent conflict. Therefore, it will likely be extremely difficult to secure water resources for a significant proportion of populations in Fragile and Conflict Affected States. However, the capacity in Organisation for Economic Co-operation and Development nations for the appropriate interventions to address this problem is reduced by an increasing reluctance to participate in interventionist operations following a decade of expeditionary warfighting mainly in Iraq and Afghanistan, and related defence cuts. Therefore, future interventions in violent conflict and securing water resources may be more indirect in nature. This paper assesses the state of understanding key areas in the present literature and highlights the gap of securing water resources during violent conflict in the absence of institutional capacity. There is a need to close this gap as a matter of urgency by formulating frameworks to assess the lack of institutional oversight / framework for water resources in areas where violent conflict is prevalent; developing inclusive resource management platforms through transparency and reconciliation mechanisms; and developing endogenous confidence-building measures and evaluate how these may be encouraged by exogenous initiatives including those facilitated by the international community. This effort

  19. Design and implementation of an optimal laser pulse front tilting scheme for ultrafast electron diffraction in reflection geometry with high temporal resolution

    Directory of Open Access Journals (Sweden)

    Francesco Pennacchio

    2017-07-01

    Full Text Available Ultrafast electron diffraction is a powerful technique to investigate out-of-equilibrium atomic dynamics in solids with high temporal resolution. When diffraction is performed in reflection geometry, the main limitation is the mismatch in group velocity between the overlapping pump light and the electron probe pulses, which affects the overall temporal resolution of the experiment. A solution already available in the literature involved pulse front tilt of the pump beam at the sample, providing a sub-picosecond time resolution. However, in the reported optical scheme, the tilted pulse is characterized by a temporal chirp of about 1 ps at 1 mm away from the centre of the beam, which limits the investigation of surface dynamics in large crystals. In this paper, we propose an optimal tilting scheme designed for a radio-frequency-compressed ultrafast electron diffraction setup working in reflection geometry with 30 keV electron pulses containing up to 105 electrons/pulse. To characterize our scheme, we performed optical cross-correlation measurements, obtaining an average temporal width of the tilted pulse lower than 250 fs. The calibration of the electron-laser temporal overlap was obtained by monitoring the spatial profile of the electron beam when interacting with the plasma optically induced at the apex of a copper needle (plasma lensing effect. Finally, we report the first time-resolved results obtained on graphite, where the electron-phonon coupling dynamics is observed, showing an overall temporal resolution in the sub-500 fs regime. The successful implementation of this configuration opens the way to directly probe structural dynamics of low-dimensional systems in the sub-picosecond regime, with pulsed electrons.

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

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  1. Attainment of 40.5 pm spatial resolution using 300 kV scanning transmission electron microscope equipped with fifth-order aberration corrector.

    Science.gov (United States)

    Morishita, Shigeyuki; Ishikawa, Ryo; Kohno, Yuji; Sawada, Hidetaka; Shibata, Naoya; Ikuhara, Yuichi

    2018-02-01

    The achievement of a fine electron probe for high-resolution imaging in scanning transmission electron microscopy requires technological developments, especially in electron optics. For this purpose, we developed a microscope with a fifth-order aberration corrector that operates at 300 kV. The contrast flat region in an experimental Ronchigram, which indicates the aberration-free angle, was expanded to 70 mrad. By using a probe with convergence angle of 40 mrad in the scanning transmission electron microscope at 300 kV, we attained the spatial resolution of 40.5 pm, which is the projected interatomic distance between Ga-Ga atomic columns of GaN observed along [212] direction.

  2. Use and User Perception of Electronic Information Resources: A Case Study of Siva Institute of Frontier Technology, India

    Directory of Open Access Journals (Sweden)

    Velmurugan Chandran

    2013-12-01

    Full Text Available The present study aims to explore the use and user perception of electronic resources in Siva Institute of Frontier Technology, India. A total number of 123 users were taken into account for the study through a questionnaire-based survey method. A well-structured questionnaire was designed and distributed to the selected 200 students and staff members. 123 copies of the questionnaires were returned dully filled in and the overall response rate was 61.50 percent. The questionnaire contained both open- and close-ended questions. The collected data were classified, analyzed, and tabulated by using simple statistical methods. This study covers the impact of electronic resources on students and faculty in their academic pursuit.

  3. Challenges in the implementation of an electronic surveillance system in a resource-limited setting: Alerta, in Peru

    Directory of Open Access Journals (Sweden)

    Soto Giselle

    2008-11-01

    Full Text Available Abstract Background Infectious disease surveillance is a primary public health function in resource-limited settings. In 2003, an electronic disease surveillance system (Alerta was established in the Peruvian Navy with support from the U.S. Naval Medical Research Center Detachment (NMRCD. Many challenges arose during the implementation process, and a variety of solutions were applied. The purpose of this paper is to identify and discuss these issues. Methods This is a retrospective description of the Alerta implementation. After a thoughtful evaluation according to the Centers for Disease Control and Prevention (CDC guidelines, the main challenges to implementation were identified and solutions were devised in the context of a resource-limited setting, Peru. Results After four years of operation, we have identified a number of challenges in implementing and operating this electronic disease surveillance system. These can be divided into the following categories: (1 issues with personnel and stakeholders; (2 issues with resources in a developing setting; (3 issues with processes involved in the collection of data and operation of the system; and (4 issues with organization at the central hub. Some of the challenges are unique to resource-limited settings, but many are applicable for any surveillance system. For each of these challenges, we developed feasible solutions that are discussed. Conclusion There are many challenges to overcome when implementing an electronic disease surveillance system, not only related to technology issues. A comprehensive approach is required for success, including: technical support, personnel management, effective training, and cultural sensitivity in order to assure the effective deployment of an electronic disease surveillance system.

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

    Science.gov (United States)

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

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

  5. RESEARCH OF INFLUENCE OF QUALITY OF ELECTRONIC EDUCATIONAL RESOURCES ON QUALITY OF TRAINING WITH USE OF DISTANCE TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    H. M. Kravtsov

    2013-03-01

    Full Text Available Communication improving of educational processes requires today new approaches to the management arrangements and forming of educational policy in the field of distance learning, which is based on the use of modern information and communication technologies. An important step in this process is the continuous monitoring of the development and implementation of information technology and, in particular, the distance learning systems in higher educational establishments. The main objective of the monitoring is the impact assessment on the development of distance learning following the state educational standards, curricula, methodical and technical equipment and other factors; factors revelation that influence the implementation and outcomes of distance learning; results comparison of educational institution functioning and distance education systems in order to determine the most efficient ways of its development. The paper presents the analysis results of the dependence of the quality of educational services on the electronic educational resources. Trends in educational services development was studied by comparing the quality influence of electronic educational resources on the quality of educational services of higher pedagogical educational institutions of Ukraine as of 2009-2010 and 2012-2013. Generally, the analysis of the survey results allows evaluating quality of the modern education services as satisfactory and it can be said that almost 70% of the success of their future development depends on the quality of the used electronic educational resources and distance learning systems in particular.

  6. Tracking the Flow of Resources in Electronic Waste - The Case of End-of-Life Computer Hard Disk Drives.

    Science.gov (United States)

    Habib, Komal; Parajuly, Keshav; Wenzel, Henrik

    2015-10-20

    Recovery of resources, in particular, metals, from waste flows is widely seen as a prioritized option to reduce their potential supply constraints in the future. The current waste electrical and electronic equipment (WEEE) treatment system is more focused on bulk metals, where the recycling rate of specialty metals, such as rare earths, is negligible compared to their increasing use in modern products, such as electronics. This study investigates the challenges in recovering these resources in the existing WEEE treatment system. It is illustrated by following the material flows of resources in a conventional WEEE treatment plant in Denmark. Computer hard disk drives (HDDs) containing neodymium-iron-boron (NdFeB) magnets were selected as the case product for this experiment. The resulting output fractions were tracked until their final treatment in order to estimate the recovery potential of rare earth elements (REEs) and other resources contained in HDDs. The results further show that out of the 244 kg of HDDs treated, 212 kg comprising mainly of aluminum and steel can be finally recovered from the metallurgic process. The results further demonstrate the complete loss of REEs in the existing shredding-based WEEE treatment processes. Dismantling and separate processing of NdFeB magnets from their end-use products can be a more preferred option over shredding. However, it remains a technological and logistic challenge for the existing system.

  7. HELP (INFORMATION ELECTRONIC RESOURCE "CHRONICLE OF ONU: DATES, FACTS, EVENTS": HISTORY OF UNIVERSITY IN INFORMATION SPACE

    Directory of Open Access Journals (Sweden)

    А. М. Гавриленко

    2016-03-01

    Object of research is the help information resource "The chronicle of the Odessa national university of I. I. Mechnikov: dates, facts, events". The main objective of our article – to state the main methodological bases of creation of information resource. One of advantages of information resource is possibility of continuous updating and replenishment by new information. Main objective of creation of this information resource is systematization of material on stories of the Odessa national university of I. I. Mechnikov from the date of his basis to the present, ensuring interactive access to information on the main dates, the most significant events in life of university. The base of research are sources on the history of university, chronology of historical development, formation of infrastructure, cadres and scientific researches. In information resource the main stages of development, functioning and transformation of the Odessa University are analyzed, information on its divisions is collected. For creation of this information resource in Scientific library the method of work was developed, the main selection criteria of data are allocated. This information resource have practical value for all who is interested in history of university, historians, scientists-researchers of history of science and the city of Odessa.

  8. Atomic-resolution studies of In2O3-ZnO compounds on aberration-corrected electron microscopes

    International Nuclear Information System (INIS)

    Yu, Wentao

    2009-01-01

    In this work, the characteristic inversion domain microstructures of In 2 O 3 (ZnO) m (m=30) compounds were investigated by TEM methods. At bright-atom contrast condition, atomically resolved HR-TEM images of In 2 O 3 (ZnO) 30 were successfully acquired in [1 anti 100] zone axis of ZnO, with projected metal columns of ∝1.6 A well resolved. From contrast maxima in the TEM images, local lattice distortions at the pyramidal inversion domain boundaries were observed for the first time. Lattice displacements and the strain field in two-dimensions were visualized and measured using the 'DALI' algorithm. Atomically resolved single shot and focal series images of In 2 O 3 (ZnO) 30 were achieved in both zone axes of ZnO, [1 anti 100] and [2 anti 1 anti 10], respectively. The electron waves at the exit-plane were successfully reconstructed using the software package 'TrueImage'. Finally, a three dimensional atomic structure model for the pyramidal IDB was proposed, with an In distribution of 10%, 20%, 40%, 20% and 10% of In contents over 5 atom columns along basal planes, respectively. Through a detailed structural study of In 2 O 3 (ZnO) m compounds by using phase-contrast and Z-contrast imaging at atomic resolution, In 3+ atoms are determined with trigonal bi-pyramidal co-ordination and are distributed at the pyramidal IDBs. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-01-15

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

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

    International Nuclear Information System (INIS)

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

    1980-01-01

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

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

    International Nuclear Information System (INIS)

    Okabe, Toshio; Ura, Katsuhiko

    1994-01-01

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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

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

    International Nuclear Information System (INIS)

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

    2003-01-01

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

  14. Structure of a headful DNA-packaging bacterial virus at 2.9 Å resolution by electron cryo-microscopy.

    Science.gov (United States)

    Zhao, Haiyan; Li, Kunpeng; Lynn, Anna Y; Aron, Keith E; Yu, Guimei; Jiang, Wen; Tang, Liang

    2017-04-04

    The enormous prevalence of tailed DNA bacteriophages on this planet is enabled by highly efficient self-assembly of hundreds of protein subunits into highly stable capsids. These capsids can stand with an internal pressure as high as ∼50 atmospheres as a result of the phage DNA-packaging process. Here we report the complete atomic model of the headful DNA-packaging bacteriophage Sf6 at 2.9 Å resolution determined by electron cryo-microscopy. The structure reveals the DNA-inflated, tensed state of a robust protein shell assembled via noncovalent interactions. Remarkable global conformational polymorphism of capsid proteins, a network formed by extended N arms, mortise-and-tenon-like intercapsomer joints, and abundant β-sheet-like mainchain:mainchain intermolecular interactions, confers significant strength yet also flexibility required for capsid assembly and DNA packaging. Differential formations of the hexon and penton are mediated by a drastic α-helix-to-β-strand structural transition. The assembly scheme revealed here may be common among tailed DNA phages and herpesviruses.

  15. Quantitative strain mapping of InAs/InP quantum dots with 1 nm spatial resolution using dark field electron holography

    DEFF Research Database (Denmark)

    Cooper, David; Rouviere, Jean-Luc; Béché, Armand

    2011-01-01

    The optical properties of semiconductor quantum dots are greatly influenced by their strain state. Dark field electron holography has been used to measure the strain in InAs quantum dots grown in InP with a spatial resolution of 1 nm. A strain value of 5.4%60.1% has been determined which...

  16. Print and Electronic Resources: Usage Statistics at Guru Gobind Singh Indraprastha University Library

    Science.gov (United States)

    Kapoor, Kanta

    2010-01-01

    Purpose: The purpose of this paper is to quantify the use of electronic journals in comparison with the print collections in the Guru Gobind Singh Indraprastha University Library. Design/methodology/approach: A detailed analysis was made of the use of lending services, the Xerox facility and usage of electronic journals such as Science Direct,…

  17. Understanding intention to use electronic information resources: A theoretical extension of the technology acceptance model (TAM).

    Science.gov (United States)

    Tao, Donghua

    2008-11-06

    This study extended the Technology Acceptance Model (TAM) by examining the roles of two aspects of e-resource characteristics, namely, information quality and system quality, in predicting public health students' intention to use e-resources for completing research paper assignments. Both focus groups and a questionnaire were used to collect data. Descriptive analysis, data screening, and Structural Equation Modeling (SEM) techniques were used for data analysis. The study found that perceived usefulness played a major role in determining students' intention to use e-resources. Perceived usefulness and perceived ease of use fully mediated the impact that information quality and system quality had on behavior intention. The research model enriches the existing technology acceptance literature by extending TAM. Representing two aspects of e-resource characteristics provides greater explanatory information for diagnosing problems of system design, development, and implementation.

  18. Statistical Strategy for Inventorying and Monitoring the Ecosystem Resources of the State of Jalisco at Multiple Scales and Resolution Levels

    Science.gov (United States)

    Robin M. Reich; Hans T. Schreuder

    2006-01-01

    The sampling strategy involving both statistical and in-place inventory information is presented for the natural resources project of the Green Belt area (Centuron Verde) in the Mexican state of Jalisco. The sampling designs used were a grid based ground sample of a 90x90 m plot and a two-stage stratified sample of 30 x 30 m plots. The data collected were used to...

  19. The Development of a Long-Term, Continually Updated Global Solar Resource at 10 km Resolution: Preliminary Results From Test Processing and Continuing Plans

    Science.gov (United States)

    Stackhouse, P.; Perez, R.; Sengupta, M.; Knapp, K.; Cox, Stephen; Mikovitz, J. Colleen; Zhang, T.; Hemker, K.; Schlemmer, J.; Kivalov, S.

    2014-01-01

    Background: Considering the likelihood of global climatic weather pattern changes and the global competition for energy resources, there is an increasing need to provide improved and continuously updated global Earth surface solar resource information. Toward this end, a project was funded under the NASA Applied Science program involving the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC), National Renewable Energy Laboratory (NREL), the State University of New York/Albany (SUNY) and the NOAA National Climatic Data Center (NCDC) to provide NREL with a global long-term advanced global solar mapping production system for improved depiction of historical solar resources and variability and to provide a mechanism for continual updates of solar resource information. This new production system is made possible by the efforts of NOAA and NASA to completely reprocess the International Satellite Cloud Climatology Project (ISCCP) data set that provides satellite visible and infrared radiances together with retrieved cloud and surface properties on a 3-hourly basis beginning from July 1983. The old version of the ISCCP data provided this information for all the world TMs available geosynchronous satellite systems and NOAA TMs AVHRR data sets at a 30 km effective resolution. This new version aims to provide a new and improved satellite calibration at an effective 10 km resolution. Thus, working with SUNY, NASA will develop and test an improved production system that will enable NREL to continually update the Earth TM solar resource. Objective and Methods: In this presentation, we provide a general overview of this project together with samples of the new solar irradiance mapped data products and comparisons to surface measurements at various locations across the world. An assessment of the solar resource values relative to calibration uncertainty and assumptions are presented. Errors resulting assumptions in snow cover and background aerosol

  20. Building and Managing Electronic Resources in Digital Era in India with Special Reference to IUCAA and NIV, Pune: A Comparative Case Study

    Science.gov (United States)

    Sahu, H. K.; Singh, S. N.

    2015-04-01

    This paper discusses and presents a comparative case study of two libraries in Pune, India, Inter-University Centre for Astronomy and Astrophysics and Information Centre and Library of National Institute of Virology (Indian Council of Medical Research). It compares how both libraries have managed their e-resource collections, including acquisitions, subscriptions, and consortia arrangements, while also developing a collection of their own resources, including pre-prints and publications, video lectures, and other materials in an institutional repository. This study illustrates how difficult it is to manage electronic resources in a developing country like India, even though electronic resources are used more than print resources. Electronic resource management can be daunting, but with a systematic approach, various problems can be solved, and use of the materials will be enhanced.

  1. The level of the usage of the human resource information system and electronic recruitment in Croatian companies

    Directory of Open Access Journals (Sweden)

    Snježana Pivac

    2014-12-01

    Full Text Available Performing business according to contemporary requirements influences companies for continuous usage of modern managerial tools, such as a human resource information system (HRIS and electronic recruitment (ER. Human resources have been recognised as curtail resources and the main source of a competitive advantage in creation of successful business performance. In order to attract and select the top employees, companies use quality information software for attracting internal ones, and electronic recruitment for attracting the best possible external candidates. The main aim of this paper is to research the level of the usage of HRIS and ER within medium-size and large Croatian companies. Moreover, the additional aim of this paper is to evaluate the relationship among the usage of these modern managerial tools and the overall success of human resource management within these companies. For the purpose of this paper, primary and secondary research has been conducted in order to reveal the level of the usage of HRIS and ER as well as the overall success of human resource management in Croatian companies. The companies’ classification (HRIS and ER is done by using the non-hierarchical k-means cluster method as well as the nonparametric Kruskal Wallis test. Further, the companies are ranked by the multicriteria PROMETHEE method. Relevant nonparametric tests are used for testing the overall companies’ HRM. Finally, binary logistic regression is estimated, relating binary variable HRM and HRIS development. After detailed research, it can be concluded that large Croatian companies apply HRIS in majority (with a positive relation to HRM performance, but still require certain degrees of its development.

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

    International Nuclear Information System (INIS)

    Waitz, T.

    1999-06-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-16

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-12-15

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

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-15

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

  7. Anelasticity of olivine single crystals investigated by stress-reduction tests and high-angular resolution electron backscatter diffraction

    Science.gov (United States)

    Wallis, D.; Hansen, L. N.; Kempton, I.; Wilkinson, A. J.

    2017-12-01

    Geodynamic phenomena, including glacial isostatic adjustment and postseismic deformation, can involve transient deformation in response to changes in differential stress acting on mantle rocks. As such, rheological models of transient deformation are incorporated in predictions of associated processes, including sea-level rise and stress redistribution after earthquakes. However, experimental constraints on rheological models for transient deformation of mantle materials are sparse. In particular, experiments involving stress reductions have been lacking. Moreover, a material's response to a reduction in stress can provide clues to the microphysical processes controlling deformation. To constrain models of transient deformation of mantle rocks we performed stress-reduction tests on single crystals of olivine at 1250-1300°C. Mechanical and piezoelectric actuators controlled constant initial stress during creep. At various strain intervals stress was reduced near-instantaneously using the piezoelectric actuator, inducing both elastic and anelastic (time-dependent) lengthening of the samples. A range of magnitudes of stress reduction were applied, typically unloading 10-90% of the initial stress. High-angular resolution electron backscatter diffraction (HR-EBSD), based on cross-correlation of diffraction patterns, was used to map dislocation density and elastic strain distributions in the recovered samples. Magnitudes of anelastic back-strain increase with increasing magnitudes of stress reduction and show a marked increase when stress reductions exceed 50% of the initial stress, consistent with previous observations in metals and alloys. This observation is inconsistent with the Burgers rheological model commonly used to describe transient behaviour and suggests that the style of rheological behaviour depends on the magnitude of stress change. HR-EBSD maps reveal that the crystal lattices are smoothly curved and generally lack subgrain boundaries and elastic strain

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

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  9. MendelWeb: An Electronic Science/Math/History Resource for the WWW.

    Science.gov (United States)

    Blumberg, Roger B.

    This paper describes a hypermedia resource, called MendelWeb that integrates elementary biology, discrete mathematics, and the history of science. MendelWeb is constructed from Gregor Menders 1865 paper, "Experiments in Plant Hybridization". An English translation of Mendel's paper, which is considered to mark the birth of classical and…

  10. Helping Patrons Find Locally Held Electronic Resources: An Interlibrary Loan Perspective

    Science.gov (United States)

    Johnston, Pamela

    2016-01-01

    The University of North Texas Libraries provide extensive online access to academic journals through major vendor databases. As illustrated by interlibrary loan borrowing requests for items held in our databases, patrons often have difficulty navigating the available resources. In this study, the Interlibrary Loan staff used data gathered from the…

  11. QR Codes as Finding Aides: Linking Electronic and Print Library Resources

    Science.gov (United States)

    Kane, Danielle; Schneidewind, Jeff

    2011-01-01

    As part of a focused, methodical, and evaluative approach to emerging technologies, QR codes are one of many new technologies being used by the UC Irvine Libraries. QR codes provide simple connections between print and virtual resources. In summer 2010, a small task force began to investigate how QR codes could be used to provide information and…

  12. Analysis of improvement in performance and design parameters for enhancing resolution in an atmospheric scanning electron microscope.

    Science.gov (United States)

    Yoon, Yeo Hun; Kim, Seung Jae; Kim, Dong Hwan

    2015-12-01

    The scanning electron microscope is used in various fields to go beyond diffraction limits of the optical microscope. However, the electron pathway should be conducted in a vacuum so as not to scatter electrons. The pretreatment of the sample is needed for use in the vacuum. To directly observe large and fully hydrophilic samples without pretreatment, the atmospheric scanning electron microscope (ASEM) is needed. We developed an electron filter unit and an electron detector unit for implementation of the ASEM. The key of the electron filter unit is that electrons are transmitted while air molecules remain untransmitted through the unit. The electron detector unit collected the backscattered electrons. We conducted experiments using the selected materials with Havar foil, carbon film and SiN film. © The Author 2015. 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. Label-free cellular structure imaging with 82 nm lateral resolution using an electron-beam excitation-assisted optical microscope.

    Science.gov (United States)

    Fukuta, Masahiro; Masuda, Yuriko; Inami, Wataru; Kawata, Yoshimasa

    2016-07-25

    We present label-free and high spatial-resolution imaging for specific cellular structures using an electron-beam excitation-assisted optical microscope (EXA microscope). Images of the actin filament and mitochondria of stained HeLa cells, obtained by fluorescence and EXA microscopy, were compared to identify cellular structures. Based on these results, we demonstrated the feasibility of identifying label-free cellular structures at a spatial resolution of 82 nm. Using numerical analysis, we calculated the imaging depth region and determined the spot size of a cathodoluminescent (CL) light source to be 83 nm at the membrane surface.

  14. Global agricultural land resources--a high resolution suitability evaluation and its perspectives until 2100 under climate change conditions.

    Directory of Open Access Journals (Sweden)

    Florian Zabel

    Full Text Available Changing natural conditions determine the land's suitability for agriculture. The growing demand for food, feed, fiber and bioenergy increases pressure on land and causes trade-offs between different uses of land and ecosystem services. Accordingly, an inventory is required on the changing potentially suitable areas for agriculture under changing climate conditions. We applied a fuzzy logic approach to compute global agricultural suitability to grow the 16 most important food and energy crops according to the climatic, soil and topographic conditions at a spatial resolution of 30 arc seconds. We present our results for current climate conditions (1981-2010, considering today's irrigated areas and separately investigate the suitability of densely forested as well as protected areas, in order to investigate their potentials for agriculture. The impact of climate change under SRES A1B conditions, as simulated by the global climate model ECHAM5, on agricultural suitability is shown by comparing the time-period 2071-2100 with 1981-2010. Our results show that climate change will expand suitable cropland by additionally 5.6 million km2, particularly in the Northern high latitudes (mainly in Canada, China and Russia. Most sensitive regions with decreasing suitability are found in the Global South, mainly in tropical regions, where also the suitability for multiple cropping decreases.

  15. Eavesdropping on Electronic Guidebooks: Observing Learning Resources in Shared Listening Environments.

    Science.gov (United States)

    Woodruff, Allison; Aoki, Paul M.; Grinter, Rebecca E.; Hurst, Amy; Szymanski, Margaret H.; Thornton, James D.

    This paper describes an electronic guidebook, "Sotto Voce," that enables visitors to share audio information by eavesdropping on each others guidebook activity. The first section discusses the design and implementation of the guidebook device, key aspects of its user interface, the design goals for the audio environment, the eavesdropping…

  16. High-resolution multi-model projections of onshore wind resources over Portugal under a changing climate

    Science.gov (United States)

    Nogueira, Miguel; Soares, Pedro M. M.; Tomé, Ricardo; Cardoso, Rita M.

    2018-05-01

    We present a detailed evaluation of wind energy density (WED) over Portugal, based on the EURO-CORDEX database of high-resolution regional climate model (RCM) simulations. Most RCMs showed reasonable accuracy in reproducing the observed near-surface wind speed. The climatological patterns of WED displayed large sub-regional heterogeneity, with higher values over coastal regions and steep orography. Subsequently, we investigated the future changes of WED throughout the twenty-first century, considering mid- and end-century periods, and two emission scenarios (RCP4.5 and RCP8.5). On the yearly average, the multi-model ensemble WED changes were below 10% (15%) under RCP4.5 (RCP8.5). However, the projected WED anomalies displayed strong seasonality, dominated by low positive values in summer (< 10% for both scenarios), negative values in winter and spring (up to - 10% (- 20%) under RCP4.5 (RCP8.5)), and stronger negative anomalies in autumn (up to - 25% (- 35%) under RCP4.5 (RCP8.5)). These projected WED anomalies displayed large sub-regional variability. The largest reductions (and lowest increases) are linked to the northern and central-eastern elevated terrain, and the southwestern coast. In contrast, the largest increases (and lowest reductions) are linked to the central-western orographic features of moderate elevation. The projections also showed changes in inter-annual variability of WED, with small increases for annual averages, but with distinct behavior when considering year-to-year variability over a specific season: small increases in winter, larger increases in summer, slight decrease in autumn, and no relevant change in spring. The changes in inter-annual variability also displayed strong dependence on the underlying terrain. Finally, we found significant model spread in the magnitude of projected WED anomalies and inter-annual variability, affecting even the signal of the changes.

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

    Science.gov (United States)

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

    2018-01-01

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

  18. Calibration for medium resolution off-axis electron holography using a flexible dual-lens imaging system in a JEOL ARM 200F microscope

    International Nuclear Information System (INIS)

    Cantu-Valle, Jesus; Ruiz-Zepeda, Francisco; Mendoza-Santoyo, Fernando; Jose-Yacaman, Miguel; Ponce, Arturo

    2014-01-01

    In this work the calibration of a medium resolution off-axis electron holography using a dual-lens imaging system in a JEOL ARM 200F is shown. The objective dual-lens configuration allows adjusting the field of view from 35 nm to 2.5 μm. Subsequently, the parameters used in phase shift reconstruction were calibrated considering biprism voltage versus fringe spacing (σ) and versus fringe width (W). The reliability of the transmission electron microscope performance using these parameters was achieved using gold nanoparticles of known size and adjusting the excitation voltage of the lenses. - Highlights: • We presented the off-axis electron holography calibration in dual-lens mode of a JEOL ARM 200F. • We provide optimal conditions for a wide field of views varying the objective lens excitation. • The calibration was made using Au-nanoparticles controlling fringe width, spacing and contrast. • Application of electron holography to nanoparticles is also shown

  19. Visualising reacting single atoms under controlled conditions: Advances in atomic resolution in situ Environmental (Scanning) Transmission Electron Microscopy (E(S)TEM)

    Science.gov (United States)

    Boyes, Edward D.; Gai, Pratibha L.

    2014-02-01

    Advances in atomic resolution Environmental (Scanning) Transmission Electron Microscopy (E(S)TEM) for probing gas-solid catalyst reactions in situ at the atomic level under controlled reaction conditions of gas environment and temperature are described. The recent development of the ESTEM extends the capability of the ETEM by providing the direct visualisation of single atoms and the atomic structure of selected solid state heterogeneous catalysts in their working states in real-time. Atomic resolution E(S)TEM provides a deeper understanding of the dynamic atomic processes at the surface of solids and their mechanisms of operation. The benefits of atomic resolution-E(S)TEM to science and technology include new knowledge leading to improved technological processes with substantial economic benefits, improved healthcare, reductions in energy needs and the management of environmental waste generation. xml:lang="fr"

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

    International Nuclear Information System (INIS)

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

    1977-12-01

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

  1. Calibration for medium resolution off-axis electron holography using a flexible dual-lens imaging system in a JEOL ARM 200F microscope.

    Science.gov (United States)

    Cantu-Valle, Jesus; Ruiz-Zepeda, Francisco; Mendoza-Santoyo, Fernando; Jose-Yacaman, Miguel; Ponce, Arturo

    2014-12-01

    In this work the calibration of a medium resolution off-axis electron holography using a dual-lens imaging system in a JEOL ARM 200F is shown. The objective dual-lens configuration allows adjusting the field of view from 35nm to 2.5μm. Subsequently, the parameters used in phase shift reconstruction were calibrated considering biprism voltage versus fringe spacing (σ) and versus fringe width (W). The reliability of the transmission electron microscope performance using these parameters was achieved using gold nanoparticles of known size and adjusting the excitation voltage of the lenses. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Development and evolution of The Knowledge Hub for Pathology and related electronic resources.

    Science.gov (United States)

    Hardwick, David F; Sinard, John; Silva, Fred

    2011-06-01

    The Knowledge Hub for Pathology was created to provide authenticated and validated knowledge for United States and Canadian Academy of Pathology members and pathologists worldwide with access to the Web. Using the material presented at the annual meeting of the United States and Canadian Academy of Pathology with existing selection and review procedures ensured that these criteria were met without added costly procedures. Further submissions for courses and research papers are provided in electronic format and funded by universities and hospitals for their creation; thus, the principal costs borne by the United States and Canadian Academy of Pathology are Web site-posting costs. Use has escalated rapidly from 2 million hits in 2002 to 51 million in 2009 with use by 35,000 pathologists from now a total of 180 countries. This true "freemium" model is a successful process as are more traditional continuing professional development course structures such as Anatomic Pathology Electronic Case Series, a "premium" model for learning electronically also sponsored by the United States and Canadian Academy of Pathology. Copyright © 2011 Elsevier Inc. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-07

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  5. An Exploratory study on the use of LibAnswers to Resolve, Track and Monitor Electronic Resources Issues: The KAUST Library experience

    KAUST Repository

    Ramli, Rindra M.

    2017-01-01

    An Exploratory study on KAUST library use of LibAnswers in resolving electronic resources questions received in LibAnswers. It describes the findings of the questions received in LibAnswers. The author made suggestions based on the findings to improve the reference services in responding to e-resources questions.

  6. An Exploratory study on the use of LibAnswers to Resolve, Track and Monitor Electronic Resources Issues: The KAUST Library experience

    KAUST Repository

    Ramli, Rindra M.

    2017-05-03

    An Exploratory study on KAUST library use of LibAnswers in resolving electronic resources questions received in LibAnswers. It describes the findings of the questions received in LibAnswers. The author made suggestions based on the findings to improve the reference services in responding to e-resources questions.

  7. Designing a model of electronic human resource management’s implementation at the Ministry of Communications and Information Technology

    Directory of Open Access Journals (Sweden)

    Mirali Seyednaghavi

    2017-06-01

    Full Text Available : In the first phase of this study a model for electronic human resource management in government agencies based on new public services was explored by using software MAXQDA, then in the second phase, relationship between the elements of the theory were tested using software Smart PLS2. So the aim of this study is to design a model of electronic human resource management’s implementation at the Ministry of Communications and Information Technology. In this regard, according to Strauss and Corbin’s structured plan, five hypotheses were tested. Quantitative data analysis indicates that the pressures of the policies and global perspectives cause to move toward e-HRM. Among the contextual conditions macro structural mechanisms, considerations of actors, governance considerations have a significant impact on the strategy of new public services and therefore lead to the consequences of its implementation in public organizations. The findings suggest that e-HRM does not have a positive and meaningful impact on new public services, and in our country, although the recent political developments have somehow removed the gap between public policy makers, administrators, and the public, but there is still a long way to go.

  8. Preference and Use of Electronic Information and Resources by Blind/Visually Impaired in NCR Libraries in India

    Directory of Open Access Journals (Sweden)

    Shailendra Kumar

    2013-06-01

    Full Text Available This paper aims to determine the preference and use of electronic information and resources by blind/visually impaired users in the leading National Capital Region (NCR libraries of India. Survey methodology has been used as the basic research tool for data collection with the help of questionnaires. The 125 in total users surveyed in all the five libraries were selected randomly on the basis of willingness of the users with experience of working in digital environments to participate in the survey. The survey results were tabulated and analyzed with descriptive statistics methods using Excel software and 'Stata version 11'. The findings reveal that ICT have a positive impact in the lives of people with disabilities as it helps them to work independently and increases the level of confidence among them. The Internet is the most preferred medium of access to information among the majority of blind/visually impaired users. The 'Complexity of content available on the net' is found as the major challenge faced during Internet use by blind users of NCR libraries. 'Audio books on CDs/DVDs and DAISY books' are the most preferred electronic resources among the majority of blind/visually impaired users. This study will help the library professionals and organizations/institutions serving people with disabilities to develop effective library services for blind/visually impaired users in the digital environment on the basis of findings on information usage behavior in the study.

  9. Remote sensing of potential lunar resources. 2: High spatial resolution mapping of spectral reflectance ratios and implications for nearside mare TiO2 content`

    Science.gov (United States)

    Melendrez, David E.; Johnson, Jeffrey R.; Larson, Stephen M.; Singer, Robert B.

    1994-01-01

    High spatial resolution maps illustrating variations in spectral reflectance 400/560 nm ratio values have been generated for the following mare regions: (1) the border between southern Mare Serenitatis and northern Mare Tranquillitatis (including the MS-2 standard area and Apollo 17 landing site), (2) central Mare Tranquillitatis, (3) Oceanus Procellarum near Seleucus, and (4) southern Oceanus Procellarum and Flamsteed. We have also obtained 320-1000 nm reflectance spectra of several sites relative to MS-2 to facilitate scaling of the images and provide additional information on surface composition. Inferred TiO2 abundances for these mare regions have been determined using an empirical calibration which relates the weight percent TiO2 in mature mare regolith to the observed 400/560 nm ratio. Mare areas with high TiO2 abundances are probably rich in ilmenite (FeTiO3) a potential lunar resource. The highest potential TiO2 concentrations we have identified in the nearside maria occur in central Mare Tranquillitatis. Inferred TiO2 contents for these areas are greater than 9 wt% and are spatially consistent with the highest-TiO2 regions mapped previously at lower spatial resolution. We note that the morphology of surface units with high 400/560 nm ratio values increases in complexity at higher spatial resolutions. Comparisons have been made with previously published geologic maps, Lunar Orbiter IV, and ground-based images, and some possible morphologic correlatins have been found between our mapped 400/560 nm ratio values and volcanic landforms such as lava flows, mare domes, and collapse pits.

  10. Internet and electronic resources for inflammatory bowel disease: a primer for providers and patients.

    Science.gov (United States)

    Fortinsky, Kyle J; Fournier, Marc R; Benchimol, Eric I

    2012-06-01

    Patients with inflammatory bowel disease (IBD) are increasingly turning to the Internet to research their condition and engage in discourse on their experiences. This has resulted in new dynamics in the relationship between providers and their patients, with misinformation and advertising potentially presenting barriers to the cooperative patient-provider partnership. This article addresses important issues of online IBD-related health information and social media activity, such as quality, reliability, objectivity, and privacy. We reviewed the medical literature on the quality of online information provided to IBD patients, and summarized the most commonly accessed Websites related to IBD. We also assessed the activity on popular social media sites (such as Facebook, Twitter, and YouTube), and evaluated currently available applications for use by IBD patients and providers on mobile phones and tablets. Through our review of the literature and currently available resources, we developed a list of recommended online resources to strengthen patient participation in their care by providing reliable, comprehensive educational material. Copyright © 2011 Crohn's & Colitis Foundation of America, Inc.

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

    Science.gov (United States)

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

    2008-02-26

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

  12. Electronic medical records in diabetes consultations: participants' gaze as an interactional resource.

    Science.gov (United States)

    Rhodes, Penny; Small, Neil; Rowley, Emma; Langdon, Mark; Ariss, Steven; Wright, John

    2008-09-01

    Two routine consultations in primary care diabetes clinics are compared using extracts from video recordings of interactions between nurses and patients. The consultations were chosen to present different styles of interaction, in which the nurse's gaze was either primarily toward the computer screen or directed more toward the patient. Using conversation analysis, the ways in which nurses shift both gaze and body orientation between the computer screen and patient to influence the style, pace, content, and structure of the consultation were investigated. By examining the effects of different levels of engagement between the electronic medical record and the embodied patient in the consultation room, we argue for the need to consider the contingent nature of the interface of technology and the person in the consultation. Policy initiatives designed to deliver what is considered best-evidenced practice are modified in the micro context of the interactions of the consultation.

  13. Granulometric composition study of mineral resources using opto-electronic devices and Elsieve software system

    Directory of Open Access Journals (Sweden)

    Kaminski Stanislaw

    2016-01-01

    Full Text Available The use of mechanical sieves has a great impact on measurement results because occurrence of anisometric particles causes undercounting the average size. Such errors can be avoided by using opto-electronic measuring devices that enable measurement of particles from 10 μm up to a few dozen millimetres in size. The results of measurement of each particle size fraction are summed up proportionally to its weight with the use of Elsieve software system and for every type of material particle-size distribution can be obtained. The software allows further statistical interpretation of the results. Beam of infrared radiation identifies size of particles and counts them precisely. Every particle is represented by an electronic impulse proportional to its size. Measurement of particles in aqueous suspension that replaces the hydrometer method can be carried out by using the IPS L analyser (range from 0.2 to 600 μm. The IPS UA analyser (range from 0.5 to 2000 μm is designed for measurement in the air. An ultrasonic adapter enables performing measurements of moist and aggregated particles from 0.5 to 1000 μm. The construction and software system allow to determine second dimension of the particle, its shape coefficient and specific surface area. The AWK 3D analyser (range from 0.2 to 31.5 mm is devoted to measurement of various powdery materials with subsequent determination of particle shape. The AWK B analyser (range from 1 to 130 mm measures materials of thick granulation and shape of the grains. The presented method of measurement repeatedly accelerates and facilitates study of granulometric composition.

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

    Science.gov (United States)

    Entringer, Anthony G.

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

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

    Science.gov (United States)

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

    2017-12-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  17. Automated conflict resolution issues

    Science.gov (United States)

    Wike, Jeffrey S.

    1991-01-01

    A discussion is presented of how conflicts for Space Network resources should be resolved in the ATDRSS era. The following topics are presented: a description of how resource conflicts are currently resolved; a description of issues associated with automated conflict resolution; present conflict resolution strategies; and topics for further discussion.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-07-15

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

  19. An (e, 2e + ion) study of low-energy electron-impact ionization and fragmentation of tetrahydrofuran with high mass and energy resolutions

    Science.gov (United States)

    Ren, Xueguang; Pflüger, Thomas; Weyland, Marvin; Baek, Woon Yoon; Rabus, Hans; Ullrich, Joachim; Dorn, Alexander

    2014-10-01

    We study the low-energy (E0 = 26 eV) electron-impact induced ionization and fragmentation of tetrahydrofuran using a reaction microscope. All three final-state charged particles, i.e., two outgoing electrons and one fragment ion, are detected in triple coincidence such that the momentum vectors and, consequently, the kinetic energies for charged reaction products are determined. The ionic fragments are clearly identified in the experiment with a mass resolution of 1 amu. The fragmentation pathways of tetrahydrofuran are investigated by measuring the ion kinetic energy spectra and the binding energy spectra where an energy resolution of 1.5 eV has been achieved using the recently developed photoemission electron source. Here, we will discuss the fragmentation reactions for the cations C4H8O+, C4H7O+, C2H3O+, C3H_6^+, C3H_5^+, C3H_3^+, CH3O+, CHO+, and C2H_3^+.

  20. The influence of experimental resolution and background upon ion-induced vsub(e) approximately equal to vsub(i) electron distributions measured behind solid foils; and reply

    International Nuclear Information System (INIS)

    Chiu, K.C.R.; McGowan, J.W.; Meckbach, W.; Sarmiento, G.S.; Steckelmacher, W.; Lucas, M.W.

    1979-01-01

    It is stated that some confusion has developed with regard to the correct procedure necessary to compare charge exchange to the continuum (CEC) theories and experiment for ion-beam-foil collisions where the emitted electrons have velocities vsub(e) approximately equal to vsub(1) and that to make such comparisons it is necessary that (a) the instrumental resolutions in angle and absolute value of velocity be folded into the theoretical double differential cross section, and (b) if the emission of CEC electrons occurs only because of interaction with the outermost atomic layers, those electrons originating from further inside the foil be subtracted as background. It is felt that Steckelmacher et al (J. Phys. B.; 11: 2711 (1978)) did not properly account for these considerations in their comparison of theoretical and experimental results. In a reply Steckelmacher and Lucas, while agreeing that confusion has arisen in the literature, state that possible errors due to insufficiently low values in the ratio of velocity resolution to angular acceptance were overcome in their work by careful experimental design but suggest that the main area of disagreement concerns the treatment of direct ionisation background. (U.K.)

  1. Structure analysis of OmpC, one of the major proteins in the outer membrane of E. coli, by high resolution electron microscopy

    International Nuclear Information System (INIS)

    Chang, C.F.

    1983-07-01

    This dissertation is concerned with the structure analysis of a pore-forming membrane protein, OmpC, which is one of the major proteins in the outer membrane of Escherichia coli. In order to obtain structural information it was necessary to develop a suitable technique for preparing two-dimensional crystalline arrays of this membrane protein in an unfixed, unstained and hydrated condition. Electron micrographs were recorded at exposures of less than 5 electrons/A 2 in order to avoid severe radiation damage. The resulting images were crystallographically averaged, in order to overcome the statistical limitations associated with the low electron exposures. The resulting images, which extend to a resolution of approx. 13.5 A, lend themselves to a natural interpretation that is consistent with the mass density of protein, water and lipid, prior data from 2-D and 3-D structure studies of negatively stained specimens at approx. = 20 A resolution, and published spectroscopic data on the peptide chain secondary structure

  2. Green Supply Chain Collaboration for Fashionable Consumer Electronics Products under Third-Party Power Intervention—A Resource Dependence Perspective

    Directory of Open Access Journals (Sweden)

    Jiuh-Biing Sheu

    2014-05-01

    Full Text Available Under third-party power intervention (TPPI, which increases uncertainty in task environments, complex channel power interplays and restructuring are indispensable among green supply chain members as they move toward sustainable collaborative relationships for increased viability and competitive advantage. From the resource dependence perspective, this work presents a novel conceptual model to investigate the influence of political and social power on channel power restructuring and induced green supply chain collaboration in brander-retailer bidirectional green supply chains of fashionable consumer electronics products (FCEPs. An FCEP refers to the consumer electronics product (e.g., personal computers, mobile phones, computer notebooks, and game consoles with the features of a well-known brand associated, a short product lifecycle, timely and fashionable design fit for market trends, and quick responsiveness to the variations of market demands. The proposed model is tested empirically using questionnaire data obtained from retailers in the FCEP brander-retailer distribution channels. Analytical results reveal that as an extension of political and social power, TPPI positively affects the reciprocal interdependence of dyadic members and reduces power asymmetry, thereby enhancing the collaborative relationship of dyadic members and leading to improved green supply chain performance. Therein, reciprocal interdependence underlying collaborative relationship is the key to reducing the external environmental uncertainties in the TPPI context.

  3. The management of online resources and long-term saving of electronic documents by transfer into the digital space

    Directory of Open Access Journals (Sweden)

    Marius Daniel MAREŞ

    2011-12-01

    The electronic archive refers to the electronic storage system, along with the totality of electronic-type stored documents, while using as storage support any environment that can support storing and from which an electronic document can be presented.

  4. FamPlex: a resource for entity recognition and relationship resolution of human protein families and complexes in biomedical text mining.

    Science.gov (United States)

    Bachman, John A; Gyori, Benjamin M; Sorger, Peter K

    2018-06-28

    Normalization Task dataset demonstrated the utility of FamPlex in other settings. FamPlex is an effective resource for improving named entity recognition, grounding, and relationship resolution in automated reading of biomedical text. The content in FamPlex is available in both tabular and Open Biomedical Ontology formats at https://github.com/sorgerlab/famplex under the Creative Commons CC0 license and has been integrated into the TRIPS/DRUM and REACH reading systems.

  5. Multiple resolution chirp reflectometry for fault localization and diagnosis in a high voltage cable in automotive electronics

    Science.gov (United States)

    Chang, Seung Jin; Lee, Chun Ku; Shin, Yong-June; Park, Jin Bae

    2016-12-01

    A multiple chirp reflectometry system with a fault estimation process is proposed to obtain multiple resolution and to measure the degree of fault in a target cable. A multiple resolution algorithm has the ability to localize faults, regardless of fault location. The time delay information, which is derived from the normalized cross-correlation between the incident signal and bandpass filtered reflected signals, is converted to a fault location and cable length. The in-phase and quadrature components are obtained by lowpass filtering of the mixed signal of the incident signal and the reflected signal. Based on in-phase and quadrature components, the reflection coefficient is estimated by the proposed fault estimation process including the mixing and filtering procedure. Also, the measurement uncertainty for this experiment is analyzed according to the Guide to the Expression of Uncertainty in Measurement. To verify the performance of the proposed method, we conduct comparative experiments to detect and measure faults under different conditions. Considering the installation environment of the high voltage cable used in an actual vehicle, target cable length and fault position are designed. To simulate the degree of fault, the variety of termination impedance (10 Ω , 30 Ω , 50 Ω , and 1 \\text{k} Ω ) are used and estimated by the proposed method in this experiment. The proposed method demonstrates advantages in that it has multiple resolution to overcome the blind spot problem, and can assess the state of the fault.

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

    Science.gov (United States)

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

    2017-10-01

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

  7. Construction of an apparatus for the investigation of inelastic electron scattering processes at high energy resolution and experimental determination of appearance energies of various atoms, molecules and small van-der-Waals clusters

    International Nuclear Information System (INIS)

    Winkler, C.

    1993-03-01

    A new experimental setup is presented, which enables the investigation of inelastic electron scattering processes at high energy resolution with dE n + cluster ions, n>3, is supported by these measurements

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

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  9. Calibration of high-dynamic-range, finite-resolution x-ray pulse-height spectrometers for extracting electron energy distribution data from the PFRC-2 device

    Science.gov (United States)

    Swanson, C.; Jandovitz, P.; Cohen, S. A.

    2017-10-01

    Knowledge of the full x-ray energy distribution function (XEDF) emitted from a plasma over a large dynamic range of energies can yield valuable insights about the electron energy distribution function (EEDF) of that plasma and the dynamic processes that create them. X-ray pulse height detectors such as Amptek's X-123 Fast SDD with Silicon Nitride window can detect x-rays in the range of 200eV to 100s of keV. However, extracting EEDF from this measurement requires precise knowledge of the detector's response function. This response function, including the energy scale calibration, the window transmission function, and the resolution function, can be measured directly. We describe measurements of this function from x-rays from a mono-energetic electron beam in a purpose-built gas-target x-ray tube. Large-Z effects such as line radiation, nuclear charge screening, and polarizational Bremsstrahlung are discussed.

  10. The role of symmetry in the theory of inelastic high-energy electron scattering and its application to atomic-resolution core-loss imaging.

    Science.gov (United States)

    Dwyer, C

    2015-04-01

    The inelastic scattering of a high-energy electron in a solid constitutes a bipartite quantum system with an intrinsically large number of excitations, posing a considerable challenge for theorists. It is demonstrated how and why the utilization of symmetries, or approximate symmetries, can lead to significant improvements in both the description of the scattering physics and the efficiency of numerical computations. These ideas are explored thoroughly for the case of core-loss excitations, where it is shown that the coupled angular momentum basis leads to dramatic improvements over the bases employed in previous work. The resulting gains in efficiency are demonstrated explicitly for K-, L- and M-shell excitations, including such excitations in the context of atomic-resolution imaging in the scanning transmission electron microscope. The utilization of other symmetries is also discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

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

    1989-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1989-01-01

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

  13. Laser resolution of unpolarized-electron scattering cross sections into spin-conserved and spin-flip components

    International Nuclear Information System (INIS)

    Ritchie, B.

    1981-01-01

    The theory is presented for one-photon free-free absorption by electrons scattering from high-Z atoms. The absorption cross section provides sufficient information to resolve the unpolarized-electron total cross section, Vertical Barf(theta)Vertical Bar 2 +Vertical Barg(theta)Vertical Bar 2 , into its individual components for spin-nonflip, Vertical Barf(theta)Vertical Bar 2 , and spin-flip, Vertical Barg(theta)Vertical Bar 2 , scattering. The observation of a spin-polarization effect for a spin-independent process (free-free absorption) is analogous to the Fano effect for bound-free absorption

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

    NARCIS (Netherlands)

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

    2009-01-01

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

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

    Science.gov (United States)

    Heinemann, K.

    1987-01-01

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

  16. Development of an Electronic Medical Record Based Alert for Risk of HIV Treatment Failure in a Low-Resource Setting

    Science.gov (United States)

    Puttkammer, Nancy; Zeliadt, Steven; Balan, Jean Gabriel; Baseman, Janet; Destiné, Rodney; Domerçant, Jean Wysler; France, Garilus; Hyppolite, Nathaelf; Pelletier, Valérie; Raphael, Nernst Atwood; Sherr, Kenneth; Yuhas, Krista; Barnhart, Scott

    2014-01-01

    Background The adoption of electronic medical record systems in resource-limited settings can help clinicians monitor patients' adherence to HIV antiretroviral therapy (ART) and identify patients at risk of future ART failure, allowing resources to be targeted to those most at risk. Methods Among adult patients enrolled on ART from 2005–2013 at two large, public-sector hospitals in Haiti, ART failure was assessed after 6–12 months on treatment, based on the World Health Organization's immunologic and clinical criteria. We identified models for predicting ART failure based on ART adherence measures and other patient characteristics. We assessed performance of candidate models using area under the receiver operating curve, and validated results using a randomly-split data sample. The selected prediction model was used to generate a risk score, and its ability to differentiate ART failure risk over a 42-month follow-up period was tested using stratified Kaplan Meier survival curves. Results Among 923 patients with CD4 results available during the period 6–12 months after ART initiation, 196 (21.2%) met ART failure criteria. The pharmacy-based proportion of days covered (PDC) measure performed best among five possible ART adherence measures at predicting ART failure. Average PDC during the first 6 months on ART was 79.0% among cases of ART failure and 88.6% among cases of non-failure (pART initiation were added to PDC, the risk score differentiated between those who did and did not meet failure criteria over 42 months following ART initiation. Conclusions Pharmacy data are most useful for new ART adherence alerts within iSanté. Such alerts offer potential to help clinicians identify patients at high risk of ART failure so that they can be targeted with adherence support interventions, before ART failure occurs. PMID:25390044

  17. Development of an electronic medical record based alert for risk of HIV treatment failure in a low-resource setting.

    Directory of Open Access Journals (Sweden)

    Nancy Puttkammer

    Full Text Available The adoption of electronic medical record systems in resource-limited settings can help clinicians monitor patients' adherence to HIV antiretroviral therapy (ART and identify patients at risk of future ART failure, allowing resources to be targeted to those most at risk.Among adult patients enrolled on ART from 2005-2013 at two large, public-sector hospitals in Haiti, ART failure was assessed after 6-12 months on treatment, based on the World Health Organization's immunologic and clinical criteria. We identified models for predicting ART failure based on ART adherence measures and other patient characteristics. We assessed performance of candidate models using area under the receiver operating curve, and validated results using a randomly-split data sample. The selected prediction model was used to generate a risk score, and its ability to differentiate ART failure risk over a 42-month follow-up period was tested using stratified Kaplan Meier survival curves.Among 923 patients with CD4 results available during the period 6-12 months after ART initiation, 196 (21.2% met ART failure criteria. The pharmacy-based proportion of days covered (PDC measure performed best among five possible ART adherence measures at predicting ART failure. Average PDC during the first 6 months on ART was 79.0% among cases of ART failure and 88.6% among cases of non-failure (p<0.01. When additional information including sex, baseline CD4, and duration of enrollment in HIV care prior to ART initiation were added to PDC, the risk score differentiated between those who did and did not meet failure criteria over 42 months following ART initiation.Pharmacy data are most useful for new ART adherence alerts within iSanté. Such alerts offer potential to help clinicians identify patients at high risk of ART failure so that they can be targeted with adherence support interventions, before ART failure occurs.

  18. Innovative direct energy conversion systems using electronic adiabatic processes of electron fluid in solid conductors: new plants of electrical power and hydrogen gas resources without environmental pollutions

    International Nuclear Information System (INIS)

    Kondoh, Y.; Kondo, M.; Shimoda, K.; Takahashi, T.

    2001-07-01

    It is shown that using a novel recycling process of the environmental thermal energy, innovative permanent auto-working direct energy converter systems (PA-DEC systems) from the environmental thermal to electrical and/or chemical potential (TE/CP) energies, abbreviated as PA-TE/CP-DEC systems, can be used for new auto-working electrical power plants and the plants of the compressible and conveyable hydrogen gas resources at various regions in the whole world, with contributions to the world peace and the economical development in the south part of the world. It is shown that the same physical mechanism by free electrons and electrical potential determined by temperature in conductors, which include semiconductors, leads to the Peltier effect and the Seebeck one. It is experimentally clarified that the long distance separation between two π type elements of the heat absorption (HAS) and the production one (HPS) of the Peltier effect circuit system or between the higher temperature side (HTS) and the lower one (LTS) of the Seebeck effect circuit one does not change in the whole for the both effects. By using present systems, we do not need to use petrified fuels such as coals, oils, and natural gases in order to decrease the greenhouse effect by the CO 2 surrounding the earth. Furthermore, we do not need plats of nuclear fissions that left radiating wastes, i.e., with no environmental pollutions. The PA-TE/CP-DEC systems can be applicable for several km scale systems to the micro ones, such as the plants of the electrical power, the compact transportable hydrogen gas resources, a large heat energy container, which can be settled at far place from thermal energy absorbing area, the refrigerators, the air conditioners, home electrical apparatuses, and further the computer elements. It is shown that the simplest PA-TE/CP-DEC system can be established by using only the Seebeck effect components and the resolving water ones. It is clarified that the externally applied

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

    International Nuclear Information System (INIS)

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

    1983-01-01

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

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

    Science.gov (United States)

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

    2015-06-01

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