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Sample records for resolution transmission electron

  1. Image Resolution in Scanning Transmission Electron Microscopy

    SciTech Connect

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

    2008-06-26

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

  2. Image resolution and sensitivity in an environmental transmission electron microscope.

    PubMed

    Jinschek, J R; Helveg, S

    2012-11-01

    An environmental transmission electron microscope provides unique means for the atomic-scale exploration of nanomaterials during the exposure to a reactive gas environment. Here we examine conditions to obtain such in situ observations in the high-resolution transmission electron microscopy (HRTEM) mode with an image resolution of 0.10nm. This HRTEM image resolution threshold is mapped out under different gas conditions, including gas types and pressures, and under different electron optical settings, including electron beam energies, doses and dose-rates. The 0.10nm resolution is retainable for H(2) at 1-10mbar. Even for N(2), the 0.10nm resolution threshold is reached up to at least 10mbar. The optimal imaging conditions are determined by the electron beam energy and the dose-rate as well as an image signal-to-noise (S/N) ratio that is consistent with Rose's criterion of S/N≥5. A discussion on the electron-gas interactions responsible for gas-induced resolution deterioration is given based on interplay with complementary electron diffraction (ED), scanning transmission electron microscopy (STEM) as well as electron energy loss spectroscopy (EELS) data.

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

    PubMed

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

    2010-01-01

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

  4. High-resolution transmission electron microscopy: the ultimate nanoanalytical technique.

    PubMed

    Thomas, John Meurig; Midgley, Paul A

    2004-06-07

    To be able to determine the elemental composition and morphology of individual nanoparticles consisting of no more than a dozen or so atoms that weigh a few zeptograms (10(-21) g) is but one of the attainments of modern electron microscopy. With slightly larger specimens (embracing a few unit cells of the structure) their symmetry, crystallographic phase, unit-cell dimension, chemical composition and often the valence state (from parallel electron spectroscopic measurements) of the constituent atoms may also be determined using a scanning beam of electrons of ca. 0.5 nm diameter. Nowadays electron crystallography, which treats the digital data of electron diffraction (ED) and high-resolution transmission electron microscope (HRTEM) images of minute (ca. 10(-18)g) specimens in a quantitatively rigorous manner, solves hitherto unknown structures just as X-ray diffraction does with bulk single crystals. In addition, electron tomography (see cover photograph and its animation) enables a three-dimensional picture of the internal structure of minute objects, such as nanocatalysts in a single pore, as well as structural faults such as micro-fissures, to be constructed with a resolution of 1 nm from an angular series of two-dimensional (projected) images. Very recently (since this article was first written) a new meaning has been given to electron crystallography as a result of the spatio-temporal resolution of surface phenomena achieved on a femtosecond timescale.

  5. Quantitative high-resolution transmission electron microscopy of single atoms.

    PubMed

    Gamm, Björn; Blank, Holger; Popescu, Radian; Schneider, Reinhard; Beyer, André; Gölzhäuser, Armin; Gerthsen, Dagmar

    2012-02-01

    Single atoms can be considered as the most basic objects for electron microscopy to test the microscope performance and basic concepts for modeling image contrast. In this work high-resolution transmission electron microscopy was applied to image single platinum, molybdenum, and titanium atoms in an aberration-corrected transmission electron microscope. The atoms are deposited on a self-assembled monolayer substrate that induces only negligible contrast. Single-atom contrast simulations were performed on the basis of Weickenmeier-Kohl and Doyle-Turner form factors. Experimental and simulated image intensities are in quantitative agreement on an absolute intensity scale, which is provided by the vacuum image intensity. This demonstrates that direct testing of basic properties such as form factors becomes feasible.

  6. Spatial resolution and information transfer in scanning transmission electron microscopy.

    PubMed

    Peng, Yiping; Oxley, Mark P; Lupini, Andrew R; Chisholm, Matthew F; Pennycook, Stephen J

    2008-02-01

    The relation between image resolution and information transfer is explored. It is shown that the existence of higher frequency transfer in the image is just a necessary but not sufficient condition for the achievement of higher resolution. Adopting a two-point resolution criterion, we suggest that a 10% contrast level between two features in an image should be used as a practical definition of resolution. In the context of scanning transmission electron microscopy, it is shown that the channeling effect does not have a direct connection with image resolution because sharp channeling peaks do not move with the scanning probe. Through a quantitative comparison between experimental image and simulation, a Fourier-space approach is proposed to estimate defocus and sample thickness. The effective atom size in Z-contrast imaging depends on the annular detector's inner angle. Therefore, an optimum angle exists for the highest resolution as a trade-off between reduced atom size and reduced signal with limited information transfer due to noise.

  7. High Resolution Transmission Electron Microscopy (HRTEM) of nanophase ferric oxides

    NASA Technical Reports Server (NTRS)

    Golden, D. C.; Morris, R. V.; Ming, D. W.; Lauer, H. V., Jr.

    1994-01-01

    Iron oxide minerals are the prime candidates for Fe(III) signatures in remotely sensed Martian surface spectra. Magnetic, Mossbauer, and reflectance spectroscopy have been carried out in the laboratory in order to understand the mineralogical nature of Martian analog ferric oxide minerals of submicron or nanometer size range. Out of the iron oxide minerals studied, nanometer sized ferric oxides are promising candidates for possible Martian spectral analogs. 'Nanophase ferric oxide (np-Ox)' is a generic term for ferric oxide/oxihydroxide particles having nanoscale (less than 10 nm) particle dimensions. Ferrihydrite, superparamagnetic particles of hematite, maghemite and goethite, and nanometer sized particles of inherently paramagnetic lepidocrocite are all examples of nanophase ferric oxides. np-Ox particles in general do not give X-ray diffraction (XRD) patterns with well defined peaks and would often be classified as X-ray amorphous. Therefore, different np-Oxs preparations should be characterized using a more sensitive technique e.g., high resolution transmission electron microscopy (HRTEM). The purpose of this study is to report the particle size, morphology and crystalline order, of five np-Ox samples by HRTEM imaging and electron diffraction (ED).

  8. Ultrahigh-Resolution Scanning Transmission Electron Microscopy with Sub-Angstrom-Sized Electron Beams

    SciTech Connect

    Abe, E.; Pennycook, Stephen J

    2005-01-01

    The scanning transmission electron microscope (STEM) with an annular dark-field (ADF) detector provides atomic-resolution incoherent images, whose resolution is dominated, to a good approximation, by the size of convergent electron beams. Improving a spherical aberration of microscope objective lenses has been successful in converging the beam into sub-angstrom scale, promising a remarkably higher resolution for STEM. Here we describe the performance of aberration-corrected 300kV-STEM-the world-best STEM available today. The results clearly demonstrate that a sub-angstrom resolution has been indeed achieved for not only simple structures but also structurally complex systems (quasicrystals).

  9. Metals on BN Studied by High Resolution Transmission Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Bangert, U.; Zan, R.; Ramasse, Q.; Jalil, Rashid; Riaz, Ibstam; Novoselov, K. S.

    2012-07-01

    Metal impurities, gold and nickel, have been deliberately introduced into boron-nitride (BN) sheets. The structural and topographic properties of doped BN have been studied by aberration corrected scanning transmission electron microscopy (STEM). Analysis revealed that metal atoms cluster preferentially in/on contaminated areas. The metal coverage on BN is almost the same for the same evaporated amount of 1 Å.

  10. Spatial Resolution in Scanning Electron Microscopy and Scanning Transmission Electron Microscopy Without a Specimen Vacuum Chamber.

    PubMed

    Nguyen, Kayla X; Holtz, Megan E; Richmond-Decker, Justin; Muller, David A

    2016-08-01

    A long-standing goal of electron microscopy has been the high-resolution characterization of specimens in their native environment. However, electron optics require high vacuum to maintain an unscattered and focused probe, a challenge for specimens requiring atmospheric or liquid environments. Here, we use an electron-transparent window at the base of a scanning electron microscope's objective lens to separate column vacuum from the specimen, enabling imaging under ambient conditions, without a specimen vacuum chamber. We demonstrate in-air imaging of specimens at nanoscale resolution using backscattered scanning electron microscopy (airSEM) and scanning transmission electron microscopy. We explore resolution and contrast using Monte Carlo simulations and analytical models. We find that nanometer-scale resolution can be obtained at gas path lengths up to 400 μm, although contrast drops with increasing gas path length. As the electron-transparent window scatters considerably more than gas at our operating conditions, we observe that the densities and thicknesses of the electron-transparent window are the dominant limiting factors for image contrast at lower operating voltages. By enabling a variety of detector configurations, the airSEM is applicable to a wide range of environmental experiments including the imaging of hydrated biological specimens and in situ chemical and electrochemical processes.

  11. Modeling atomic-resolution scanning transmission electron microscopy images.

    PubMed

    Findlay, Scott D; Oxley, Mark P; Allen, Leslie J

    2008-02-01

    A real-space description of inelastic scattering in scanning transmission electron microscopy is derived with particular attention given to the implementation of the projected potential approximation. A hierarchy of approximations to expressions for inelastic images is presented. Emphasis is placed on the conditions that must hold in each case. The expressions that justify the most direct, visual interpretation of experimental data are also the most approximate. Therefore, caution must be exercised in selecting experimental parameters that validate the approximations needed for the analysis technique used. To make the most direct, visual interpretation of electron-energy-loss spectroscopic images from core-shell excitations requires detector improvements commensurate with those that aberration correction provides for the probe-forming lens. Such conditions can be relaxed when detailed simulations are performed as part of the analysis of experimental data.

  12. Acquisition of a High Voltage/High resolution Transmission Electron Microscope.

    DTIC Science & Technology

    1988-08-21

    Electron Energy Loss Spectroscopy (EELS) The EELS is the study of energy distribution of electrons ...or aggregates of small particles can be studied directly by transmission electron mi- croscopy techniques (Fig. 7).12 17 - .,’ L -. 𔃾 " ", , M. 1.5 "m...characterization of the ceramic producrs in terms of imaging at all levels of resolution (from optical to atomic 21 resolution) by direct

  13. Resolution enhancement in transmission electron microscopy with 60-kV monochromated electron source

    SciTech Connect

    Morishita, Shigeyuki; Mukai, Masaki; Sawada, Hidetaka; Suenaga, Kazutomo

    2016-01-04

    Transmission electron microscopy (TEM) at low accelerating voltages is useful to obtain images with low irradiation damage. For a low accelerating voltage, linear information transfer, which determines the resolution for observation of single-layered materials, is largely limited by defocus spread, which improves when a narrow energy spread is used in the electron source. In this study, we have evaluated the resolution of images obtained at 60 kV by TEM performed with a monochromated electron source. The defocus spread has been evaluated by comparing diffractogram tableaux from TEM images obtained under nonmonochromated and monochromated illumination. The information limits for different energy spreads were precisely measured by using diffractograms with a large beam tilt. The result shows that the information limit reaches 0.1 nm with an energy width of 0.10 eV. With this monochromated source and a higher-order aberration corrector, we have obtained images of single carbon atoms in a graphene sheet by TEM at 60 kV.

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

    PubMed

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

    2011-08-01

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

  15. Ultrahigh-resolution Scanning Transmission Microscopy with Sub-?ngstrom-Sized Electron Beams

    SciTech Connect

    Abe, E.; Pennycook, Stephen J

    2005-01-01

    The scanning transmission electron microscope(STEM)with an annular dark-field(ADF) detector provides atomic-resolution incoherent images, whose resolution is dominated, to a good approximation, by the size of convergent electron beams. Improving a spherical aberra- tion of microscope objective lenses has been successful in converging the beam into sub- scale, promising a remarkably higher resolution for STEM. Here we describe the performance of aberration-corrected 300kV-STEM - the world-best STEM available today. The results clearly demonstrate that a sub- ngstrom resolution has been indeed achieved for not only simple structures but also structurally complex systems(quasicrystals).

  16. Practical Considerations for High Spatial and Temporal Resolution Dynamic Transmission Electron Microscopy

    SciTech Connect

    Armstrong, M; Boyden, K; Browning, N D; Campbell, G H; Colvin, J D; DeHope, B; Frank, A M; Gibson, D J; Hartemann, F; Kim, J S; King, W E; LaGrange, T B; Pyke, B J; Reed, B W; Shuttlesworth, R M; Stuart, B C; Torralva, B R

    2006-05-01

    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 5 x 10{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.

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

    PubMed

    Barthel, J; Thust, A

    2013-11-01

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

  18. New area detector for atomic-resolution scanning transmission electron microscopy.

    PubMed

    Shibata, Naoya; Kohno, Yuji; Findlay, Scott D; Sawada, Hidetaka; Kondo, Yukihito; Ikuhara, Yuichi

    2010-01-01

    A new area detector for atomic-resolution scanning transmission electron microscopy (STEM) is developed and tested. The circular detector is divided into 16 segments which are individually optically coupled with photomultiplier tubes. Thus, 16 atomic-resolution STEM images which are sensitive to the spatial distribution of scattered electrons on the detector plane can be simultaneously obtained. This new detector can be potentially used not only for the simultaneous formation of common bright-field, low-angle annular dark-field and high-angle annular dark-field images, but also for the quantification of images by detecting the full range of scattered electrons and even for exploring novel atomic-resolution imaging modes by post-processing combination of the individual images.

  19. Nanoscale deformation analysis with high-resolution transmission electron microscopy and digital image correlation

    DOE PAGES

    Wang, Xueju; Pan, Zhipeng; Fan, Feifei; ...

    2015-09-10

    We present an application of the digital image correlation (DIC) method to high-resolution transmission electron microscopy (HRTEM) images for nanoscale deformation analysis. The combination of DIC and HRTEM offers both the ultrahigh spatial resolution and high displacement detection sensitivity that are not possible with other microscope-based DIC techniques. We demonstrate the accuracy and utility of the HRTEM-DIC technique through displacement and strain analysis on amorphous silicon. Two types of error sources resulting from the transmission electron microscopy (TEM) image noise and electromagnetic-lens distortions are quantitatively investigated via rigid-body translation experiments. The local and global DIC approaches are applied for themore » analysis of diffusion- and reaction-induced deformation fields in electrochemically lithiated amorphous silicon. As a result, the DIC technique coupled with HRTEM provides a new avenue for the deformation analysis of materials at the nanometer length scales.« less

  20. Nanoscale deformation analysis with high-resolution transmission electron microscopy and digital image correlation

    SciTech Connect

    Wang, Xueju; Pan, Zhipeng; Fan, Feifei; Wang, Jiangwei; Liu, Yang; Mao, Scott X.; Zhu, Ting; Xia, Shuman

    2015-09-10

    We present an application of the digital image correlation (DIC) method to high-resolution transmission electron microscopy (HRTEM) images for nanoscale deformation analysis. The combination of DIC and HRTEM offers both the ultrahigh spatial resolution and high displacement detection sensitivity that are not possible with other microscope-based DIC techniques. We demonstrate the accuracy and utility of the HRTEM-DIC technique through displacement and strain analysis on amorphous silicon. Two types of error sources resulting from the transmission electron microscopy (TEM) image noise and electromagnetic-lens distortions are quantitatively investigated via rigid-body translation experiments. The local and global DIC approaches are applied for the analysis of diffusion- and reaction-induced deformation fields in electrochemically lithiated amorphous silicon. As a result, the DIC technique coupled with HRTEM provides a new avenue for the deformation analysis of materials at the nanometer length scales.

  1. Correlative super-resolution fluorescence and metal replica transmission electron microscopy

    PubMed Central

    Sochacki, Kem A.; Shtengel, Gleb; van Engelenburg, Schuyler B.; Hess, Harald F.; Taraska, Justin W.

    2014-01-01

    Super-resolution localization microscopy is combined with a complementary imaging technique, transmission electron microscopy of metal replicas, to locate proteins on the landscape of the cellular plasma membrane at the nanoscale. Robust correlation on the scale of 20 nm is validated by imaging endogenous clathrin (with 2D and 3D PALM/TEM) and the method is further used to find the previously unknown 3D position of epsin on clathrin coated structures. PMID:24464288

  2. Atomic Resolution Imaging at an Ultralow Accelerating Voltage by a Monochromatic Transmission Electron Microscope

    NASA Astrophysics Data System (ADS)

    Morishita, Shigeyuki; Mukai, Masaki; Suenaga, Kazu; Sawada, Hidetaka

    2016-10-01

    Transmission electron microscopy using low-energy electrons would be very useful for atomic resolution imaging of specimens that would be damaged at higher energies. However, the resolution at low voltages is degraded because of geometrical and chromatic aberrations. In the present study, we diminish the effect of these aberrations by using a delta-type corrector and a monochromator. The dominant residual aberration in a delta-type corrector, which is the sixth-order three-lobe aberration, is counterbalanced by other threefold aberrations. Defocus spread caused by chromatic aberration is reduced by using a monochromated beam with an energy spread of 0.05 eV. We obtain images of graphene and demonstrate atomic resolution at an ultralow accelerating voltage of 15 kV.

  3. Effect of microscope parameter and specimen thickness of spatial resolution of transmission electron backscatter diffraction.

    PubMed

    Wang, Y Z; Kong, M G; Liu, Z W; Lin, C C; Zeng, Y

    2016-10-01

    The spatial resolution of transmission electron backscatter diffraction (t-EBSD) with a standard conventional EBSD detector was evaluated quantitatively based on the calculation of the correlation coefficient of transmission patterns which were acquired across a twin boundary in the sample of austenitic steel. The results showed that the resolution of t-EBSD improved from tens of nanometres to below 10 nm with increasing accelerating voltage and thinning of specimen thickness. High voltage could enhance the penetration depth and reduce the scattering angle. And the thinning of specimen thickness would result in decreasing of the scattering events according to the theory of thermal diffuse scattering (TDS). In addition, the transmission patterns were found to be weak and noisy if the specimen was too thin, because of the decreasing intensity detected by the screen. Consequently, in this work, the best spatial resolution of 7 nm was achieved at 30 kV and 41 nm thickness. Moreover, the specimen thickness range was also discussed using Monte-Carlo simulation. This approach was helpful to account for the differences of measured spatial resolutions, by t-EBSD, of lamellas with different thickness.

  4. High-energy-resolution monochromator for aberration-corrected scanning transmission electron microscopy/electron energy-loss spectroscopy.

    PubMed

    Krivanek, Ondrej L; Ursin, Jonathan P; Bacon, Neil J; Corbin, George J; Dellby, Niklas; Hrncirik, Petr; Murfitt, Matthew F; Own, Christopher S; Szilagyi, Zoltan S

    2009-09-28

    An all-magnetic monochromator/spectrometer system for sub-30 meV energy-resolution electron energy-loss spectroscopy in the scanning transmission electron microscope is described. It will link the energy being selected by the monochromator to the energy being analysed by the spectrometer, without resorting to decelerating the electron beam. This will allow it to attain spectral energy stability comparable to systems using monochromators and spectrometers that are raised to near the high voltage of the instrument. It will also be able to correct the chromatic aberration of the probe-forming column. It should be able to provide variable energy resolution down to approximately 10 meV and spatial resolution less than 1 A.

  5. The probe profile and lateral resolution of scanning transmission electron microscopy of thick specimens.

    PubMed

    Demers, Hendrix; Ramachandra, Ranjan; Drouin, Dominique; de Jonge, Niels

    2012-06-01

    Lateral profiles of the electron probe of scanning transmission electron microscopy (STEM) were simulated at different vertical positions in a micrometers-thick carbon sample. The simulations were carried out using the Monte Carlo method in CASINO software. A model was developed to fit the probe profiles. The model consisted of the sum of a Gaussian function describing the central peak of the profile and two exponential decay functions describing the tail of the profile. Calculations were performed to investigate the fraction of unscattered electrons as a function of the vertical position of the probe in the sample. Line scans were also simulated over gold nanoparticles at the bottom of a carbon film to calculate the achievable resolution as a function of the sample thickness and the number of electrons. The resolution was shown to be noise limited for film thicknesses less than 1 μm. Probe broadening limited the resolution for thicker films. The validity of the simulation method was verified by comparing simulated data with experimental data. The simulation method can be used as quantitative method to predict STEM performance or to interpret STEM images of thick specimens.

  6. Soot Nanostructure: Using Fringe Analysis Software on High Resolution Transmission Electron Microscopy of Carbon Soot

    NASA Technical Reports Server (NTRS)

    King, James D.

    2004-01-01

    Using high resolution transmission electron images of carbon nanotubes and carbon particles, we are able to use image analysis program to determine several carbon fringe properties, including length, separation, curvature and orientation. Results are shown in the form of histograms for each of those quantities. The combination of those measurements can give a better indication of the graphic structure within nanotubes and particles of carbon and can distinguish carbons based upon fringe properties. Carbon with longer, straighter and closer spaced fringes are considered graphite, while amorphous carbon contain shorter, less structured fringes.

  7. Crack tip shielding observed with high-resolution transmission electron microscopy.

    PubMed

    Adhika, Damar Rastri; Tanaka, Masaki; Daio, Takeshi; Higashida, Kenji

    2015-10-01

    The dislocation shielding field at a crack tip was experimentally proven at the atomic scale by measuring the local strain in front of the crack tip using high-resolution transmission electron microscopy (HRTEM) and geometric phase analysis (GPA). Single crystalline (110) silicon wafers were employed. Cracks were introduced using a Vickers indenter at room temperature. The crack tip region was observed using HRTEM followed by strain measurements using GPA. The measured strain field at the crack tip was compressive owing to dislocation shielding, which is in good agreement with the strain field calculated from elastic theory.

  8. Crack tip shielding observed with high-resolution transmission electron microscopy

    PubMed Central

    Adhika, Damar Rastri; Tanaka, Masaki; Daio, Takeshi; Higashida, Kenji

    2015-01-01

    The dislocation shielding field at a crack tip was experimentally proven at the atomic scale by measuring the local strain in front of the crack tip using high-resolution transmission electron microscopy (HRTEM) and geometric phase analysis (GPA). Single crystalline (110) silicon wafers were employed. Cracks were introduced using a Vickers indenter at room temperature. The crack tip region was observed using HRTEM followed by strain measurements using GPA. The measured strain field at the crack tip was compressive owing to dislocation shielding, which is in good agreement with the strain field calculated from elastic theory. PMID:26115957

  9. Investigation of non-linear imaging in high-resolution transmission electron microscopy.

    PubMed

    Chang, Yunjie; Wang, Yumei; Cui, Yanxiang; Ge, Binghui

    2016-12-01

    Transmission cross-coefficient theory and pseudo-weak-phase object approximation theory were combined to investigate the non-linear imaging in high-resolution transmission electron microscopy (HRTEM). The analytical expressions of linear and non-linear imaging components in diffractogram were obtained and changes of linear and non-linear components over sample thickness were analyzed. Moreover, the linear and non-linear components are found to be an odd and even-function of the defocus and Cs, respectively. Based on this, a method for separating the linear and non-linear contrasts in Cs-corrected (non-zero Cs conditions included) HRTEM images was proposed, and its effectiveness was confirmed by image simulations with AlN as an example.

  10. Live Bacterial Physiology Visualized with 5 nm Resolution Using Scanning Transmission Electron Microscopy.

    PubMed

    Kennedy, Eamonn; Nelson, Edward M; Tanaka, Tetsuya; Damiano, John; Timp, Gregory

    2016-02-23

    It is now possible to visualize at nanometer resolution the infection of a living biological cell with virus without compromising cell viability using scanning transmission electron microscopy (STEM). To provide contrast while preserving viability, Escherichia coli and P1 bacteriophages were first positively stained with a very low concentration of uranyl acetate in minimal phosphate medium and then imaged with low-dose STEM in a microfluidic liquid flow cell. Under these conditions, it was established that the median lethal dose of electrons required to kill half the tested population was LD50 = 30 e(-)/nm(2), which coincides with the disruption of a wet biological membrane, according to prior reports. Consistent with the lateral resolution and high-contrast signal-to-noise ratio (SNR) inferred from Monte Carlo simulations, images of the E. coli membrane, flagella, and the bacteriophages were acquired with 5 nm resolution, but the cumulative dose exceeded LD50. On the other hand, with a cumulative dose below LD50 (and lower SNR), it was still possible to visualize the infection of E. coli by P1, showing the insertion of viral DNA within 3 s, with 5 nm resolution.

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

    NASA Astrophysics Data System (ADS)

    Loyer-Prost, M.; Merot, J.-S.; Ribis, J.; Le Bouar, Y.; Chaffron, L.; Legendre, F.

    2016-10-01

    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) 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.

  12. Quantitative atomic resolution mapping using high-angle annular dark field scanning transmission electron microscopy.

    PubMed

    Van Aert, S; Verbeeck, J; Erni, R; Bals, S; Luysberg, M; Van Dyck, D; Van Tendeloo, G

    2009-09-01

    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.

  13. Well-orientated cubic boron nitride nanocrystals as studied by high-resolution transmission electron microscopy.

    PubMed

    Tsiaoussis, I; Frangis, N

    2006-09-01

    In a boron nitride thin film, grown on a Si (100) substrate by radio frequency magnetron sputtering, a striking nanostructure is observed by high-resolution transmission electron microscopy. It consists of cubic boron nitride nanocrystals with a rather good triangular shape, pointing always to the substrate. The nanocrystals are usually highly defected and present their own interesting internal structure. Texture formation is observed within a nanocrystal, with all the subgrains observed to have a common <011> axis, which is also approximately parallel to a <011> axis of the Si substrate, i.e. the nanocrystals are very well structurally orientated in relation to the Si substrate (self-organized). Dislocations and stacking faults are also found in the nanocrystals.

  14. High resolution transmission electron microscopic in-situ observations of plastic deformation of compressed nanocrystalline gold

    SciTech Connect

    Wang, Guoyong; Lian, Jianshe; Jiang, Qing; Sun, Sheng; Zhang, Tong-Yi

    2014-09-14

    Nanocrystalline (nc) metals possess extremely high strength, while their capability to deform plastically has been debated for decades. Low ductility has hitherto been considered an intrinsic behavior for most nc metals, due to the lack of five independent slip systems actively operating during deformation in each nanograin. Here we report in situ high resolution transmission electron microscopic (HRTEM) observations of deformation process of nc gold under compression, showing the excellent ductility of individual and aggregate nanograins. Compression causes permanent change in the profile of individual nanograins, which is mediated by dislocation slip and grain rotation. The high rate of grain boundary sliding and large extent of widely exited grain rotation may meet the boundary compatibility requirements during plastic deformation. The in situ HRTEM observations suggest that nc gold is not intrinsically brittle under compressive loading.

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

    SciTech Connect

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

    2008-10-15

    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{sub 8}Al{sub 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. High resolution transmission electron microscope observation of zero-strain deformation twinning mechanisms in Ag.

    PubMed

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

    2011-04-29

    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.

  17. Enhanced light element imaging in atomic resolution scanning transmission electron microscopy.

    PubMed

    Findlay, S D; Kohno, Y; Cardamone, L A; Ikuhara, Y; Shibata, N

    2014-01-01

    We show that an imaging mode based on taking the difference between signals recorded from the bright field (forward scattering region) in atomic resolution scanning transmission electron microscopy provides an enhancement of the detectability of light elements over existing techniques. In some instances this is an enhancement of the visibility of the light element columns relative to heavy element columns. In all cases explored it is an enhancement in the signal-to-noise ratio of the image at the light column site. The image formation mechanisms are explained and the technique is compared with earlier approaches. Experimental data, supported by simulation, are presented for imaging the oxygen columns in LaAlO₃. Case studies looking at imaging hydrogen columns in YH₂ and lithium columns in Al₃Li are also explored through simulation, particularly with respect to the dependence on defocus, probe-forming aperture angle and detector collection aperture angles.

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

    PubMed Central

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

    2017-01-01

    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. PMID:28272404

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

    PubMed

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

    2017-03-08

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  1. High resolution transmission electron microscopy study of diamond films grown from fullerene precursors

    SciTech Connect

    Luo, J.S.; Gruen, D.M.; Krauss, A.R.

    1995-07-01

    High-resolution transmission electron microscopy (HRTEM) has been used to investigate the microstructure of diamond films grown by plasma-assisted chemical vapor deposition using fullerene precursors. HRTEM observations of as-grown films revealed an array of larger crystals (>200 nm) within a polycrystalline matrix of much smaller crystallites (<20 nm). The randomly oriented small crystallites were nearly free of structural imperfections such as stacking faults or twins, while the larger ones had preferred <110> orientations with respect to the Si (100) substrate and showed evidence of structural defects on the periphery of the crystals. The most common defects were V-shaped {Sigma}9 twin boundaries, which are generally believed to serve as re-entrant sites for diamond nucleation and growth. The observation of growth steps on both (111) and (110) surfaces seems to support a reaction model in which fragments of C{sub 60}, including C{sub 2}, are considered the growth species. In particular, the nanocrystallinity of the films is most likely due to a high carbon cluster density from C{sub 60} fragmentation at or near the diamond surface, which can serve as nucleation sites for the growth of new crystallites.

  2. In-Situ High-Resolution Transmission Electron Microscopy Investigation of Overheating of Cu Nanoparticles

    NASA Astrophysics Data System (ADS)

    Chen, Chunlin; Hu, Ziyu; Li, Yanfen; Liu, Limin; Mori, Hirotaro; Wang, Zhangchang

    2016-01-01

    Synthesizing and functionalizing metal nanoparticles supported on substrates is currently the subject of intensive study owing to their outstanding catalytic performances for heterogeneous catalysis. Revealing the fundamental effect of the substrates on metal nanoparticles represents a key step in clarifying mechanisms of stability and catalytic properties of these heterogeneous systems. However, direct identification of these effects still poses a significant challenge due to the complicacy of interactions between substrates and nanoparticles and also for the technical difficulty, restraining our understanding of these heterogeneous systems. Here, we combine in situ high-resolution transmission electron microscopy with molecular dynamics simulations to investigate Cu nanoparticles supported on graphite and Cu2O substrates, and demonstrate that melting behavior and thermal stability of Cu nanoparticles can be markedly influenced by substrates. The graphite-supported Cu nanoparticles do not melt during annealing at 1073 K until they vanish completely, i.e. only the sublimation occurs, while the Cu2O-supported Cu nanoparticles suffer melting during annealing at 973 K. Such selective superheating of the Cu nanoparticles can be attributed to the adsorption of a thin carbon layer on the surface of the Cu nanoparticles, which helps guide further stability enhancement of functional nanoparticles for realistic applications.

  3. Extended Depth of Field for High-Resolution Scanning Transmission Electron Microscopy

    SciTech Connect

    Hovden, Robert; Xin, Huolin L.; Muller, David A.

    2010-12-02

    Aberration-corrected scanning transmission electron microscopes (STEMs) provide sub-Angstrom lateral resolution; however, the large convergence angle greatly reduces the depth of field. For microscopes with a small depth of field, information outside of the focal plane quickly becomes blurred and less defined. It may not be possible to image some samples entirely in focus. Extended depth-of-field techniques, however, allow a single image, with all areas in focus, to be extracted from a series of images focused at a range of depths. In recent years, a variety of algorithmic approaches have been employed for bright-field optical microscopy. Here, we demonstrate that some established optical microscopy methods can also be applied to extend the ~6 nm depth of focus of a 100 kV 5th-order aberration-corrected STEM (α{sub max} = 33 mrad) to image Pt-Co nanoparticles on a thick vulcanized carbon support. These techniques allow us to automatically obtain a single image with all the particles in focus as well as a complimentary topography map.

  4. Extended depth of field for high-resolution scanning transmission electron microscopy.

    PubMed

    Hovden, Robert; Xin, Huolin L; Muller, David A

    2011-02-01

    Aberration-corrected scanning transmission electron microscopes (STEMs) provide sub-Angstrom lateral resolution; however, the large convergence angle greatly reduces the depth of field. For microscopes with a small depth of field, information outside of the focal plane quickly becomes blurred and less defined. It may not be possible to image some samples entirely in focus. Extended depth-of-field techniques, however, allow a single image, with all areas in focus, to be extracted from a series of images focused at a range of depths. In recent years, a variety of algorithmic approaches have been employed for bright-field optical microscopy. Here, we demonstrate that some established optical microscopy methods can also be applied to extend the ∼ 6 nm depth of focus of a 100 kV 5th-order aberration-corrected STEM (α max = 33 mrad) to image Pt-Co nanoparticles on a thick vulcanized carbon support. These techniques allow us to automatically obtain a single image with all the particles in focus as well as a complimentary topography map.

  5. The influence of the sample thickness on the lateral and axial resolution of aberration-corrected scanning transmission electron microscopy.

    PubMed

    Ramachandra, Ranjan; Demers, Hendrix; de Jonge, Niels

    2013-02-01

    The lateral and axial resolution of three-dimensional (3D) focal series aberration-corrected scanning transmission electron microscopy was studied for samples of different thicknesses. The samples consisted of gold nanoparticles placed on the top and at the bottom of silicon nitride membranes of thickness between 50 and 500 nm. Atomic resolution was obtained for nanoparticles on top of 50-, 100-, and 200-nm-thick membranes with respect to the electron beam traveling downward. Atomic resolution was also achieved for nanoparticles placed below 50-, 100-, and 200-nm-thick membranes but with a lower contrast at the larger thicknesses. Beam broadening led to a reduced resolution for a 500-nm-thick membrane. The influence of the beam broadening on the axial resolution was also studied using Monte Carlo simulations with a 3D sample geometry.

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

    DOEpatents

    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. Solid-gas reactions of complex oxides inside an environmental high-resolution transmission electron microscope.

    PubMed

    Sayagués, M J; Krumeich, F; Hutchison, J L

    2001-07-01

    In a gas reaction cell (GRC), installed in a high-resolution transmission electron microscope (HRTEM) (JEOL 4000EX), samples can be manipulated in an ambient atmosphere (p<50mbar). This experimental setup permits not only the observation of solid-gas reactions in situ at close to the atomic level but also the induction of structural modifications under the influence of a plasma, generated by the ionization of gas particles by an intense electron beam. Solid state reactions of non-stoichiometric niobium oxides and niobium tungsten oxides with different gases (O2, H2 and He) have been carried out inside this controlled environment transmission electron microscope (CETEM), and this has led to reaction products with novel structures which are not accessible by conventional solid state synthesis methods. Monoclinic and orthorhombic Nb(12)O(29) crystallize in block structures comprising [3x4] blocks. The oxidation of the monoclinic phase occurs via a three step mechanism: firstly, a lamellar defect of composition Nb(11)O(27) is formed. Empty rectangular channels in this defect provide the diffusion paths in the subsequent oxidation. In the second step, microdomains of the Nb(22)O(54) phase are generated as an intermediate state of the oxidation process. The structure of the final product Nb(10)O(25), which consists of [3x3] blocks and tetrahedral coordinated sites, is isostructural to PNb(9)O(25). Microdomains of this apparently metastable phase appear as a product of the Nb(22)O(54) oxidation. The oxidation reaction of Nb(12)O(29) was found to be a reversible process: the reduction of the oxidation product with H(2) results in the formation of the starting Nb(12)O(29) structure. On the other hand, the block structure of Nb(12)O(29) has been destroyed by a direct treatment of the sample with H(2) while NbO in a cubic rock salt structure is produced. This in situ technique has also been applied to niobium tungsten oxides which constitute the solid solution series Nb(8-n

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

    PubMed

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

    2016-01-01

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

  9. In situ high-resolution transmission electron microscopy study of interfacial reactions of Cu thin films on amorphous silicon

    NASA Astrophysics Data System (ADS)

    Lee, Sung Bo; Choi, Duck-Kyun; Phillipp, Fritz; Jeon, Kyung-Sook; Kim, Chang Kyung

    2006-02-01

    Interfacial reactions of Cu with amorphous silicon (a-Si) in the Cu /a-Si/glass system are studied by in situ high-resolution transmission electron microscopy at 550°C. Various Cu silicides, such as η-Cu3Si, Cu15Si4, and Cu5Si, and Cu particles are observed. The formation of the Cu particles can be attributed to a heating effect from electron beam irradiation. Around the Cu silicides, crystallization of a-Si occurs. Around the Cu particles, however, crystallization does not occur. Crystallization appears to be enhanced by Cu dissolved in a-Si.

  10. Carbon Nanostructure Examined by Lattice Fringe Analysis of High Resolution Transmission Electron Microscopy Images

    NASA Technical Reports Server (NTRS)

    VanderWal, Randy L.; Tomasek, Aaron J.; Street, Kenneth; Thompson, William K.

    2002-01-01

    The dimensions of graphitic layer planes directly affect the reactivity of soot towards oxidation and growth. Quantification of graphitic structure could be used to develop and test correlations between the soot nanostructure and its reactivity. Based upon transmission electron microscopy images, this paper provides a demonstration of the robustness of a fringe image analysis code for determining the level of graphitic structure within nanoscale carbon, i.e. soot. Results, in the form of histograms of graphitic layer plane lengths, are compared to their determination through Raman analysis.

  11. Carbon Nanostructure Examined by Lattice Fringe Analysis of High Resolution Transmission Electron Microscopy Images

    NASA Technical Reports Server (NTRS)

    VanderWal, Randy L.; Tomasek, Aaron J.; Street, Kenneth; Thompson, William K.; Hull, David R.

    2003-01-01

    The dimensions of graphitic layer planes directly affect the reactivity of soot towards oxidation and growth. Quantification of graphitic structure could be used to develop and test correlations between the soot nanostructure and its reactivity. Based upon transmission electron microscopy images, this paper provides a demonstration of the robustness of a fringe image analysis code for determining the level of graphitic structure within nanoscale carbon, i.e., soot. Results, in the form of histograms of graphitic layer plane lengths, are compared to their determination through Raman analysis.

  12. Enhanced resolution of soft-materials spectroscopic imaging in the scanning transmission electron microscope

    NASA Astrophysics Data System (ADS)

    Yakovlev, Sergey

    The quantitative analysis of soft-materials morphology at nano lengths is an important scientific and technical challenge. Imaging based on spatially resolved Electron Energy-Loss Spectroscopy (EELS) enables both real-space morphological measurements and the quantitative determination of local composition without assuming a particular model as is done by scattering approaches. EELS imaging is being increasingly used in a variety of hard-materials applications. However, its application to soft materials, such as synthetic polymers and biological tissue, remains challenging because of the resolution limits imposed by the radiation sensitivity of most soft materials. This thesis explores the factors that affect the dose-limited resolution of soft materials, and it develops new approaches to improve this resolution. We show that the accuracy of compositional analysis can be compromised in order to enhance the resolution, and we successfully apply this approach to a semi-quantitative analysis of alkane-based coatings on nanosized poly(amine) nanoparticles. More generally, however, one would like to preserve compositional accuracy while using the higher electron doses required to achieve high resolution. To this end, we have discovered that the effects of radiation-induced evolution of hydrogen---a damage mechanism known to be a significant limitation in EELS studies of frozen-hydrated soft materials---can be completely avoided if very thin TEM sections are studied. We illustrate the thickness dependence of hydrogen evolution in solvated Nafion, a perflourinated ionomer, and in hydrated porcine skin. Then, working with thin sections of frozen-hydrated skin, we develop and apply a method to extract from an experimental spectrum dataset a reference spectrum that accurately represents the hydrated skin's protein component under conditions where the protein has suffered significant radiation damage. Using such an extracted reference spectrum virtually eliminates the error

  13. Aberration corrected 1.2-MV cold field-emission transmission electron microscope with a sub-50-pm resolution

    SciTech Connect

    Akashi, Tetsuya; Takahashi, Yoshio; Tanigaki, Toshiaki Shimakura, Tomokazu; Kawasaki, Takeshi; Furutsu, Tadao; Shinada, Hiroyuki; Osakabe, Nobuyuki; Müller, Heiko; Haider, Maximilian; Tonomura, Akira

    2015-02-16

    Atomic-resolution electromagnetic field observation is critical to the development of advanced materials and to the unveiling of their fundamental physics. For this purpose, a spherical-aberration corrected 1.2-MV cold field-emission transmission electron microscope has been developed. The microscope has the following superior properties: stabilized accelerating voltage, minimized electrical and mechanical fluctuation, and coherent electron emission. These properties have enabled to obtain 43-pm information transfer. On the bases of these performances, a 43-pm resolution has been obtained by correcting lens aberrations up to the third order. Observations of GaN [411] thin crystal showed a projected atomic locations with a separation of 44 pm.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    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 MoS2 will be discussed. MoS2-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.

  15. Preparation of the planarian Schmidtea mediterranea for high-resolution histology and transmission electron microscopy

    PubMed Central

    Brubacher, John L.; Vieira, Ana P.; Newmark, Phillip A.

    2014-01-01

    The flatworm Schmidtea mediterranea is an emerging model species in such fields as stem-cell biology, regeneration, and evolutionary biology. Excellent molecular tools have been developed for S. mediterranea, but ultrastructural techniques have received far less attention. Processing specimens for histology and transmission electron microscopy is notoriously idiosyncratic for particular species or specimen types. Unfortunately however, most methods for S. mediterranea described in the literature lack numerous essential details, and those few that do provide them rely on specialized equipment that may not be readily available. Here we present an optimized protocol for ultrastructural preparation of S. mediterranea. The protocol can be completed in six days, much of which is “hands-off” time. To aid with troubleshooting, we also illustrate the significant effects of seemingly minor variations in fixative, buffer concentration, and dehydration steps. This procedure will be useful for all planarian researchers, particularly those with relatively little experience in tissue processing. PMID:24556788

  16. Time-Resolved High-Resolution Transmission Electron Microscopy Using a Piezo-Driving Specimen Holder for Atomic-Scale Mechanical Interaction.

    PubMed

    Kizuka; Tanaka; Deguchi; Naruse

    1998-05-01

    : Time-resolved high-resolution transmission electron microscopy at a spatial resolution of 0.2 nm and a time resolution of 1/60 sec using a piezo-driving specimen holder is reported here. Various types of atomic processes in mechanical interaction, such as contact, bonding, deformation, and fracture, in nanometer-sized gold crystallites and carbon nanotubes are demonstrated.

  17. High resolution transmission electron microscopy characterization of fcc --> 9R transformation in nanocrystalline palladium films due to hydriding

    NASA Astrophysics Data System (ADS)

    Amin-Ahmadi, Behnam; Idrissi, Hosni; Delmelle, Renaud; Pardoen, Thomas; Proost, Joris; Schryvers, Dominique

    2013-02-01

    Sputtered nanocrystalline palladium thin films with nanoscale growth twins have been subjected to hydriding cycles. The evolution of the twin boundaries has been investigated using high resolution transmission electron microscopy. Surprisingly, the ∑3{112} incoherent twin boundaries dissociate after hydriding into two phase boundaries bounding a 9R phase. This phase which corresponds to single stacking faults located every three {111} planes in the fcc Pd structure was not expected because of the high stacking fault energy of Pd. This observation is connected to the influence of the Hydrogen on the stacking fault energy of palladium and the high compressive stresses building up during hydriding.

  18. Automated Transmission-Mode Scanning Electron Microscopy (tSEM) for Large Volume Analysis at Nanoscale Resolution

    PubMed Central

    Kuwajima, Masaaki; Mendenhall, John M.; Lindsey, Laurence F.; Harris, Kristen M.

    2013-01-01

    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 µm2 (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 µm2 (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 µm2 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. PMID:23555711

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

    PubMed

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

    2016-10-21

    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 AlxGa1-xAs, 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.

  20. Optimized deconvolution for maximum axial resolution in three-dimensional aberration-corrected scanning transmission electron microscopy.

    PubMed

    Ramachandra, Ranjan; de Jonge, Niels

    2012-02-01

    Three-dimensional (3D) datasets were recorded of gold nanoparticles placed on both sides of silicon nitride membranes using focal series aberration-corrected scanning transmission electron microscopy (STEM). Deconvolution of the 3D datasets was applied to obtain the highest possible axial resolution. The deconvolution involved two different point spread functions, each calculated iteratively via blind deconvolution. Supporting membranes of different thicknesses were tested to study the effect of beam broadening on the deconvolution. It was found that several iterations of deconvolution was efficient in reducing the imaging noise. With an increasing number of iterations, the axial resolution was increased, and most of the structural information was preserved. Additional iterations improved the axial resolution by maximal a factor of 4 to 6, depending on the particular dataset, and up to 8 nm maximal, but also led to a reduction of the lateral size of the nanoparticles in the image. Thus, the deconvolution procedure optimized for the highest axial resolution is best suited for applications where one is interested in the 3D locations of nanoparticles only.

  1. Compositional analysis with atomic column spatial resolution by 5th-order aberration-corrected scanning transmission electron microscopy.

    PubMed

    Hernández-Maldonado, David; Herrera, Miriam; Alonso-González, Pablo; González, Yolanda; González, Luisa; Gazquez, Jaume; Varela, María; Pennycook, Stephen J; Guerrero-Lebrero, María de la Paz; Pizarro, Joaquín; Galindo, Pedro L; Molina, Sergio I

    2011-08-01

    We show in this article that it is possible to obtain elemental compositional maps and profiles with atomic-column resolution across an InxGa1-xAs multilayer structure from 5th-order aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images. The compositional profiles obtained from the analysis of HAADF-STEM images describe accurately the distribution of In in the studied multilayer in good agreement with Muraki's segregation model [Muraki, K., Fukatsu, S., Shiraki, Y. & Ito, R. (1992). Surface segregation of In atoms during molecular beam epitaxy and its influence on the energy levels in InGaAs/GaAs quantums wells. Appl Phys Lett 61, 557-559].

  2. Observation of antisite domain boundaries in Cu2ZnSnS4 by atomic-resolution transmission electron microscopy.

    PubMed

    Kattan, N A; Griffiths, I J; Cherns, D; Fermín, D J

    2016-08-14

    Atomic resolution transmission electron microscopy has been used to examine antisite defects in Cu2ZnSnS4 (CZTS) kesterite crystals grown by a hot injection method. High angle annular dark field (HAADF) imaging at sub-0.1 nm resolution, and lower magnification dark field imaging using reflections sensitive to cation ordering, are used to reveal antisite domain boundaries (ADBs). These boundaries, typically 5-20 nm apart, and extending distances of 100 nm or more into the crystals, lie on a variety of planes and have displacements of the type ½[110] or ¼[201], which translate Sn, Cu and Zn cations into antisite positions. It is shown that some ADBs describe a change in the local stoichiometry by removing planes of S and either Cu or Zn atoms, implying that these boundaries can be electrically charged. The observations also showed a marked increase in cation disorder in regions within 1-2 nm of the grain surfaces suggesting that growth of the ordered crystal takes place at the interface with a disordered shell. It is estimated that the ADBs contribute on average ∼0.1 antisite defect pairs per unit cell. Although this is up to an order of magnitude less than the highest antisite defect densities reported, the presence of high densities of ADBs that may be charged suggests these defects may have a significant influence on the efficiency of CZTS solar cells.

  3. Soot Structure and Reactivity Analysis by Raman Microspectroscopy, Temperature-Programmed Oxidation, and High-Resolution Transmission Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Knauer, Markus; Schuster, Manfred E.; Su, Dangsheng; Schlögl, Robert; Niessner, Reinhard; Ivleva, Natalia P.

    2009-11-01

    Raman microspectroscopy (RM), temperature-programmed oxidation (TPO), high-resolution transmission electron microscopy (HRTEM), and electron energy loss spectroscopy (EELS) were combined to get comprehensive information on the relationship between structure and reactivity of soot in samples of spark discharge (GfG), heavy duty engine diesel (EURO VI and IV) soot, and graphite powder upon oxidation by oxygen at increasing temperatures. GfG soot and graphite powder represent the higher and lower reactivity limits. Raman microspectroscopic analysis was conducted by determination of spectral parameters using a five band fitting procedure (G, D1-D4) as well as by evaluation of the dispersive character of the D mode. The analysis of spectral parameters shows a higher degree of disorder and a higher amount of molecular carbon for untreated GfG soot samples than for samples of untreated EURO VI and EURO IV soot. The structural analysis based on the dispersive character of the D mode revealed substantial differences in ordering descending from graphite powder, EURO IV, VI to GfG soot. HRTEM images and EELS analysis of EURO IV and VI samples indicated a different morphology and a higher structural order as compared to GfG soot in full agreement with the Raman analysis. These findings are also confirmed by the reactivity of soot during oxidation (TPO), where GfG soot was found to be the most reactive and EURO IV and VI soot samples exhibited a moderate reactivity.

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

    NASA Technical Reports Server (NTRS)

    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.

  5. Observation of antisite domain boundaries in Cu2ZnSnS4 by atomic-resolution transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Kattan, N. A.; Griffiths, I. J.; Cherns, D.; Fermín, D. J.

    2016-07-01

    Atomic resolution transmission electron microscopy has been used to examine antisite defects in Cu2ZnSnS4 (CZTS) kesterite crystals grown by a hot injection method. High angle annular dark field (HAADF) imaging at sub-0.1 nm resolution, and lower magnification dark field imaging using reflections sensitive to cation ordering, are used to reveal antisite domain boundaries (ADBs). These boundaries, typically 5-20 nm apart, and extending distances of 100 nm or more into the crystals, lie on a variety of planes and have displacements of the type ½[110] or ¼[201], which translate Sn, Cu and Zn cations into antisite positions. It is shown that some ADBs describe a change in the local stoichiometry by removing planes of S and either Cu or Zn atoms, implying that these boundaries can be electrically charged. The observations also showed a marked increase in cation disorder in regions within 1-2 nm of the grain surfaces suggesting that growth of the ordered crystal takes place at the interface with a disordered shell. It is estimated that the ADBs contribute on average ~0.1 antisite defect pairs per unit cell. Although this is up to an order of magnitude less than the highest antisite defect densities reported, the presence of high densities of ADBs that may be charged suggests these defects may have a significant influence on the efficiency of CZTS solar cells.Atomic resolution transmission electron microscopy has been used to examine antisite defects in Cu2ZnSnS4 (CZTS) kesterite crystals grown by a hot injection method. High angle annular dark field (HAADF) imaging at sub-0.1 nm resolution, and lower magnification dark field imaging using reflections sensitive to cation ordering, are used to reveal antisite domain boundaries (ADBs). These boundaries, typically 5-20 nm apart, and extending distances of 100 nm or more into the crystals, lie on a variety of planes and have displacements of the type ½[110] or ¼[201], which translate Sn, Cu and Zn cations into antisite

  6. Separating strain from composition in unit cell parameter maps obtained from aberration corrected high resolution transmission electron microscopy imaging

    SciTech Connect

    Schulz, T.; Remmele, T.; Korytov, M.; Markurt, T.; Albrecht, M.; Duff, A.; Lymperakis, L.; Neugebauer, J.; Chèze, C.

    2014-01-21

    Based on the evaluation of lattice parameter maps in aberration corrected high resolution transmission electron microscopy images, we propose a simple method that allows quantifying the composition and disorder of a semiconductor alloy at the unit cell scale with high accuracy. This is realized by considering, next to the out-of-plane, also the in-plane lattice parameter component allowing to separate the chemical composition from the strain field. Considering only the out-of-plane lattice parameter component not only yields large deviations from the true local alloy content but also carries the risk of identifying false ordering phenomena like formations of chains or platelets. Our method is demonstrated on image simulations of relaxed supercells, as well as on experimental images of an In{sub 0.20}Ga{sub 0.80}N quantum well. Principally, our approach is applicable to all epitaxially strained compounds in the form of quantum wells, free standing islands, quantum dots, or wires.

  7. Genesis of presolar diamonds: Comparative high-resolution transmission electron microscopy study of meteoritic and terrestrial nano-diamonds

    SciTech Connect

    Daulton, T.L. |; Eisenhour, D.D.; Buseck, P.R.

    1996-12-01

    Nano-diamonds isolated from acid dissolution residues of primitive carbonaceous meteorites (Allende and Murchison) were studied using high-resolution transmission electron microscopy. To discriminate among their most likely formation mechanisms, high-pressure shock-induced metamorphism or low-pressure vapor condensation. the microstructures of presolar diamond crystallites were compared to those of (terrestrial) synthesized nano-diamonds. The synthesized diamonds used for comparison in this study were produced by high-pressure shock waves generated in controlled detonations and by direct nucleation and homoepitaxial growth from the vapor phase in low-pressure chemical vapor deposition (CVD)-type processes. Microstructural features were identified that appear unique to shock metamorphism and to nucleation from the vapor phase, respectively. A comparison of these features to the microstructures found in presolar diamonds indicates that the predominant mechanism for presolar diamond formation is a vapor deposition process, suggesting a circumstellar condensation origin. A new presolar grain component has also been identified in the meteoritic residues, the (2H) hexagonal polytype of diamond (lonsdaleite). 93 refs., 17 figs., 1 tab.

  8. High resolution transmission electron microscope Imaging and first-principles simulations of atomic-scale features in graphene membrane

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Bhandari, Sagar; Yi, Wei; Bell, David; Westervelt, Robert; Kaxiras, Efthimios

    2012-02-01

    Ultra-thin membranes such as graphene[1] are of great importance for basic science and technology applications. Graphene sets the ultimate limit of thinness, demonstrating that a free-standing single atomic layer not only exists but can be extremely stable and strong [2--4]. However, both theory [5, 6] and experiments [3, 7] suggest that the existence of graphene relies on intrinsic ripples that suppress the long-wavelength thermal fluctuations which otherwise spontaneously destroy long range order in a two dimensional system. Here we show direct imaging of the atomic features in graphene including the ripples resolved using monochromatic aberration-corrected transmission electron microscopy (TEM). We compare the images observed in TEM with simulated images based on an accurate first-principles total potential. We show that these atomic scale features can be mapped through accurate first-principles simulations into high resolution TEM contrast. [1] Geim, A. K. & Novoselov, K. S. Nat. Mater. 6, 183-191, (2007). [2] Novoselov, K. S.et al. Science 306, 666-669, (2004). [3] Meyer, J. C. et al. Nature 446, 60-63, (2007). [4] Lee, C., Wei, X. D., Kysar, J. W. & Hone, J. Science 321, 385-388, (2008). [5] Nelson, D. R. & Peliti, L. J Phys-Paris 48, 1085-1092, (1987). [6] Fasolino, A., Los, J. H. & Katsnelson, M. I. Nat. Mater. 6, 858-861, (2007). [7] Meyer, J. C. et al. Solid State Commun. 143, 101-109, (2007).

  9. Characterization of Al2O3 in High-Strength Mo Alloy Sheets by High-Resolution Transmission Electron Microscopy.

    PubMed

    Zhou, Yucheng; Gao, Yimin; Wei, Shizhong; Hu, Yajie

    2016-02-01

    A novel type of alumina (Al2O3)-doped molybdenum (Mo) alloy sheet was prepared by a hydrothermal method and a subsequent powder metallurgy process. Then the characterization of α-Al2O3 was investigated using high-resolution transmission electron microscopy as the research focus. The tensile strength of the Al2O3-doped Mo sheet is 43-85% higher than that of the pure Mo sheet, a very obvious reinforcement effect. The sub-micron and nanometer-scale Al2O3 particles can increase the recrystallization temperature by hindering grain boundary migration and improve the tensile strength by effectively blocking the motion of the dislocations. The Al2O3 particles have a good bond with the Mo matrix and there exists an amorphous transition layer at the interface between Al2O3 particles and the Mo matrix in the as-rolled sheet. The sub-structure of α-Al2O3 is characterized by a number of nanograins in the $\\left[ {2\\bar{2}1} \\right]$ direction. Lastly, a new computer-based method for indexing diffraction patterns of the hexagonal system is introduced, with 16 types of diffraction patterns of α-Al2O3 indexed.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  13. Morphometric, quantitative, and three-dimensional analysis of the heart muscle fibers of old rats: transmission electron microscopy and high-resolution scanning electron microscopy methods.

    PubMed

    Cury, Diego Pulzatto; Dias, Fernando José; Sosthenes, Marcia Consentino Kronka; Dos Santos Haemmerle, Carlos Alexandre; Ogawa, Koichi; Da Silva, Marcelo Cavenaghi Pereira; Mardegan Issa, João Paulo; Iyomasa, Mamie Mizusaki; Watanabe, Ii-Sei

    2013-02-01

    This research investigated the morphological, morphometric, and ultrastructural cardiomyocyte characteristics of male Wistar rats at 18 months of age. The animals were euthanized using an overdose of anesthesia (ketamine and xylazine, 150/10 mg/kg) and perfused transcardially, after which samples were collected for light microscopy, transmission electron microscopy, and high-resolution scanning electron microscopy. The results showed that cardiomyocyte arrangement was disposed parallel between the mitochondria and the A-, I-, and H-bands and their M- and Z-lines from the sarcomere. The sarcomere junction areas had intercalated disks, a specific structure of heart muscle. The ultrastructural analysis revealed several mitochondria of various sizes and shapes intermingled between the blood capillaries and their endothelial cells; some red cells inside vessels are noted. The muscle cell sarcolemma could be observed associated with the described structures. The cardiomyocytes of old rats presented an average sarcomere length of 2.071 ± 0.09 μm, a mitochondrial volume density (Vv) of 0.3383, a mitochondrial average area of 0.537 ± 0.278 μm(2), a mitochondrial average length of 1.024 ± 0.352 μm, an average mitochondrial cristae thickness of 0.038 ± 0.09 μm and a ratio of mitochondrial greater length/lesser length of 1.929 ± 0.965. Of the observed mitochondrial shapes, 23.4% were rounded, 45.3% were elongated, and 31.1% had irregular profiles. In this study, we analyzed the morphology and morphometry of cardiomyocytes in old rats, focusing on mitochondria. These data are important for researchers who focus the changes in cardiac tissue, especially changes owing to pathologies and drug administration that may or may not be correlated with aging.

  14. Oxidation-state sensitive imaging of cerium dioxide by atomic-resolution low-angle annular dark field scanning transmission electron microscopy

    PubMed Central

    Johnston-Peck, Aaron C.; Winterstein, Jonathan P.; Roberts, Alan D.; DuChene, Joseph S.; Qian, Kun; Sweeny, Brendan C.; Wei, Wei David; Sharma, Renu; Stach, Eric A.; Herzing, Andrew A.

    2016-01-01

    Low-angle annular dark field (LAADF) scanning transmission electron microscopy (STEM) imaging is presented as a method that is sensitive to the oxidation state of cerium ions in CeO2 nanoparticles. This relationship was validated through electron energy loss spectroscopy (EELS), in situ measurements, as well as multislice image simulations. Static displacements caused by the increased ionic radius of Ce3+ influence the electron channeling process and increase electron scattering to low angles while reducing scatter to high angles. This process manifests itself by reducing the high-angle annular dark field (HAADF) signal intensity while increasing the LAADF signal intensity in close proximity to Ce3+ ions. This technique can supplement STEM-EELS and in so doing, relax the experimental challenges associated with acquiring oxidation state information at high spatial resolutions. PMID:26744830

  15. Oxidation-state sensitive imaging of cerium dioxide by atomic-resolution low-angle annular dark field scanning transmission electron microscopy.

    PubMed

    Johnston-Peck, Aaron C; Winterstein, Jonathan P; Roberts, Alan D; DuChene, Joseph S; Qian, Kun; Sweeny, Brendan C; Wei, Wei David; Sharma, Renu; Stach, Eric A; Herzing, Andrew A

    2016-03-01

    Low-angle annular dark field (LAADF) scanning transmission electron microscopy (STEM) imaging is presented as a method that is sensitive to the oxidation state of cerium ions in CeO2 nanoparticles. This relationship was validated through electron energy loss spectroscopy (EELS), in situ measurements, as well as multislice image simulations. Static displacements caused by the increased ionic radius of Ce(3+) influence the electron channeling process and increase electron scattering to low angles while reducing scatter to high angles. This process manifests itself by reducing the high-angle annular dark field (HAADF) signal intensity while increasing the LAADF signal intensity in close proximity to Ce(3+) ions. This technique can supplement STEM-EELS and in so doing, relax the experimental challenges associated with acquiring oxidation state information at high spatial resolutions.

  16. Visualising reacting single atoms under controlled conditions: Advances in atomic resolution in situ Environmental (Scanning) Transmission Electron Microscopy (E(S)TEM)

    NASA Astrophysics Data System (ADS)

    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"

  17. Optimal experimental design for the detection of light atoms from high-resolution scanning transmission electron microscopy images

    SciTech Connect

    Gonnissen, J.; De Backer, A.; Martinez, G. T.; Van Aert, S.; Dekker, A. J. den; Rosenauer, A.; Sijbers, J.

    2014-08-11

    We report an innovative method to explore the optimal experimental settings to detect light atoms from scanning transmission electron microscopy (STEM) images. Since light elements play a key role in many technologically important materials, such as lithium-battery devices or hydrogen storage applications, much effort has been made to optimize the STEM technique in order to detect light elements. Therefore, classical performance criteria, such as contrast or signal-to-noise ratio, are often discussed hereby aiming at improvements of the direct visual interpretability. However, when images are interpreted quantitatively, one needs an alternative criterion, which we derive based on statistical detection theory. Using realistic simulations of technologically important materials, we demonstrate the benefits of the proposed method and compare the results with existing approaches.

  18. Electronically controlled automatic transmission

    SciTech Connect

    Ohkubo, M.; Shiba, H.; Nakamura, K.

    1989-03-28

    This patent describes an electronically controlled automatic transmission having a manual valve working in connection with a manual shift lever, shift valves operated by solenoid valves which are driven by an electronic control circuit previously memorizing shift patterns, and a hydraulic circuit controlled by these manual valve and shift valves for driving brakes and a clutch in order to change speed. Shift patterns of 2-range and L-range, in addition to a shift pattern of D-range, are memorized previously in the electronic control circuit, an operation switch is provided which changes the shift pattern of the electronic control circuit to any shift pattern among those of D-range, 2-range and L-range at time of the manual shift lever being in a D-range position, a releasable lock mechanism is provided which prevents the manual shift lever from entering 2-range and L-range positions, and the hydraulic circuit is set to a third speed mode when the manual shift lever is in the D-range position. The circuit is set to a second speed mode when it is in the 2-range position, and the circuit is set to a first speed mode when it is in the L-range position, respectively, in case where the shift valves are not working.

  19. Low voltage transmission electron microscopy of graphene.

    PubMed

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

    2015-02-04

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

  20. Transmission electron microscope studies of extraterrestrial materials

    NASA Technical Reports Server (NTRS)

    Keller, Lindsay P.

    1995-01-01

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

  1. Liquid Cell Transmission Electron Microscopy.

    PubMed

    Liao, Hong-Gang; Zheng, Haimei

    2016-05-27

    Liquid cell transmission electron microscopy (TEM) has attracted significant interest in recent years. With nanofabricated liquid cells, it has been possible to image through liquids using TEM with subnanometer resolution, and many previously unseen materials dynamics have been revealed. Liquid cell TEM has been applied to many areas of research, ranging from chemistry to physics, materials science, and biology. So far, topics of study include nanoparticle growth and assembly, electrochemical deposition and lithiation for batteries, tracking and manipulation of nanoparticles, catalysis, and imaging of biological materials. In this article, we first review the development of liquid cell TEM and then highlight progress in various areas of research. In the study of nanoparticle growth, the electron beam can serve both as the illumination source for imaging and as the input energy for reactions. However, many other research topics require the control of electron beam effects to minimize electron beam damage. We discuss efforts to understand electron beam-liquid matter interactions. Finally, we provide a perspective on future challenges and opportunities in liquid cell TEM.

  2. Liquid Cell Transmission Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Liao, Hong-Gang; Zheng, Haimei

    2016-05-01

    Liquid cell transmission electron microscopy (TEM) has attracted significant interest in recent years. With nanofabricated liquid cells, it has been possible to image through liquids using TEM with subnanometer resolution, and many previously unseen materials dynamics have been revealed. Liquid cell TEM has been applied to many areas of research, ranging from chemistry to physics, materials science, and biology. So far, topics of study include nanoparticle growth and assembly, electrochemical deposition and lithiation for batteries, tracking and manipulation of nanoparticles, catalysis, and imaging of biological materials. In this article, we first review the development of liquid cell TEM and then highlight progress in various areas of research. In the study of nanoparticle growth, the electron beam can serve both as the illumination source for imaging and as the input energy for reactions. However, many other research topics require the control of electron beam effects to minimize electron beam damage. We discuss efforts to understand electron beam-liquid matter interactions. Finally, we provide a perspective on future challenges and opportunities in liquid cell TEM.

  3. Identifying the crystallinity, phase, and arsenic uptake of the nanomineral schwertmannite using analytical high resolution transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    French, R. A.; Kim, B.; Murayama, M.; Hochella, M. F.

    2010-12-01

    Schwertmannite, an iron oxyhydroxide sulfate nanomineral, plays a significant role in the geochemistry of acid mine drainage (AMD) as a metastable phase with respect to goethite and by retaining toxic metals, e.g. arsenic [1]. Schwertmannite’s characteristic morphology is needles 100-300 nm long and only 5-10 nm in diameter extending from a dense aggregate. The poorly-and nano-crystalline nature of this mineral requires using high resolution electron microscopy (HRTEM) to be fully characterized. We used HRTEM to identify the polyphasic nature of natural samples of schwertmannite collected from the Iberian Pyrite Belt in Spain. In order to analyze the dense core, samples were prepared in thin section using an ultramicrotome. Data on a sample identified as pure schwertmannite through powder XRD shows the presence of 5-10 nm goethite nanocrystals making up a significant portion of one of the nanoneedle tips (Figure 1). These nanocrystals exhibit lattice fringes and faceted surfaces, both of which match that expected for goethite. The great majority of the nanoneedles are poorly-crystalline (no lattice fringes) with atomically rough surfaces which may be highly active in the uptake of As. The presence of a range of phases and crystallinities in this sample demonstrate incipient stages of the mechanism that results in transformation of schwertmannite to goethite. Further analytical TEM analyses will help us track sorption/desorption, as well as the specific locations of As within these materials upon initial formation, as well as during transformation. [1] Acero et al. (2006) GCA 70, 4130-4139. Figure 1. HRTEM image of 'schwertmannite' nanoneedle with FFT data (inset).

  4. Determination of crystal growth rates during rapid solidification of polycrystalline aluminum by nano-scale spatio-temporal resolution in situ transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Zweiacker, K.; McKeown, J. T.; Liu, C.; LaGrange, T.; Reed, B. W.; Campbell, G. H.; Wiezorek, J. M. K.

    2016-08-01

    In situ investigations of rapid solidification in polycrystalline Al thin films were conducted using nano-scale spatio-temporal resolution dynamic transmission electron microscopy. Differences in crystal growth rates and asymmetries in melt pool development were observed as the heat extraction geometry was varied by controlling the proximity of the laser-pulse irradiation and the associated induced melt pools to the edge of the transmission electron microscopy support grid, which acts as a large heat sink. Experimental parameters have been established to maximize the reproducibility of the material response to the laser-pulse-related heating and to ensure that observations of the dynamical behavior of the metal are free from artifacts, leading to accurate interpretations and quantifiable measurements with improved precision. Interface migration rate measurements revealed solidification velocities that increased consistently from ˜1.3 m s-1 to ˜2.5 m s-1 during the rapid solidification process of the Al thin films. Under the influence of an additional large heat sink, increased crystal growth rates as high as 3.3 m s-1 have been measured. The in situ experiments also provided evidence for development of a partially melted, two-phase region prior to the onset of rapid solidification facilitated crystal growth. Using the experimental observations and associated measurements as benchmarks, finite-element modeling based calculations of the melt pool evolution after pulsed laser irradiation have been performed to obtain estimates of the temperature evolution in the thin films.

  5. High-resolution transmission electron microscopy study of 1.5 nm ultrathin tunnel oxides of metal-nitride-oxide-silicon nonvolatile memory devices

    NASA Astrophysics Data System (ADS)

    Kamigaki, Yoshiaki; Minami, Shin-ichi; Shimotsu, Teruho

    1988-12-01

    Metal-nitride-oxide-silicon (MNOS) nonvolatile memory devices have an ultrathin tunnel oxide SiO2 layer and a signal-charge-stored nitride Si3N4 layer. Using high-resolution transmission electron microscopy (TEM), the cross-sectional structure of MNOS devices has been observed for the first time, including direct observation of tunnel SiO2. The following is revealed: (1) Tunnel SiO2 of 1.5 nm thickness is fabricated very uniformly on the surface of a Si substrate. (2) No mixing of tunnel SiO2 and Si3N4 is observed even though tunnel SiO2 is extremely thin. As a result, we can suggest that tunnel SiO2 in a MNOS device exhibits very stable morphology and stoichiometry characteristics.

  6. In situ fabrication and optoelectronic analysis of axial CdS/p-Si nanowire heterojunctions in a high-resolution transmission electron microscope.

    PubMed

    Zhang, Chao; Xu, Zhi; Tian, Wei; Tang, Dai-Ming; Wang, Xi; Bando, Yoshio; Fukata, Naoki; Golberg, Dmitri

    2015-04-17

    A high-precision technique was utilized to construct and characterize axial nanowire heterojunctions inside a high-resolution transmission electron microscope (HRTEM). By an in-tandem technique using an ultra-sharp tungsten probe as the nanomanipulator and an optical fiber as the optical waveguide the nanoscale CdS/p-Si axial nanowire junctions were fabricated, and in situ photocurrents from them were successfully measured. Compared to a single constituting nanowire, the CdS/p-Si axial nanowire junctions possess a photocurrent saturation effect, which protects them from damage under high voltages. Furthermore, a set of experiments reveals the clear relationship between the saturation photocurrent values and the incident light intensities. The applied technique is expected to be valuable for bottom-up nanodevice fabrications, and the regarded photocurrent saturation feature may solve the Joule heating-induced failure problem in nanowire optoelectronic devices caused by a fluctuating bias.

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

    SciTech Connect

    Zhang, C.; Golberg, D. E-mail: golberg.dmitri@nims.go.jp; Xu, Z. E-mail: golberg.dmitri@nims.go.jp; Kvashnin, D. G.; Tang, D.-M.; Xue, Y. M.; Bando, Y.; Sorokin, P. B.

    2015-08-31

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

  8. In situ high-resolution transmission electron microscopy observation of the phason-strain relaxation process in an Al-Cu-Co-Si decagonal quasicrystal

    NASA Astrophysics Data System (ADS)

    Edagawa, Keiichi; Mandal, Pranabananda; Hosono, Kaoru; Suzuki, Kunio; Takeuchi, Shin

    2004-11-01

    Transition process from a rational approximant state, which is regarded as containing a uniform phason strain in a quasicrystalline state, to the quasicrystalline state in the Al-Cu-Co-Si system has been observed by in situ high-temperature high-resolution transmission electron microscopy (HRTEM). The tiling pattern changing with lapse of time in the HRTEM image has been analyzed, and the spatial and temporal variations of the phason field have been deduced. The results show that two types of processes lead the phason-strain relaxation: one is the shrink of the area with the uniform strain by shifting the boundaries and the other a continuous strain-relaxation in the area outside of the boundary. Such processes arise from a combination of collective and successive phason flips like domino-toppling along different symmetry directions.

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

    NASA Astrophysics Data System (ADS)

    Zhang, C.; Xu, Z.; Kvashnin, D. G.; Tang, D.-M.; Xue, Y. M.; Bando, Y.; Sorokin, P. B.; Golberg, D.

    2015-08-01

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

  10. In situ fabrication and optoelectronic analysis of axial CdS/p-Si nanowire heterojunctions in a high-resolution transmission electron microscope

    NASA Astrophysics Data System (ADS)

    Zhang, Chao; Xu, Zhi; Tian, Wei; Tang, Dai-Ming; Wang, Xi; Bando, Yoshio; Fukata, Naoki; Golberg, Dmitri

    2015-04-01

    A high-precision technique was utilized to construct and characterize axial nanowire heterojunctions inside a high-resolution transmission electron microscope (HRTEM). By an in-tandem technique using an ultra-sharp tungsten probe as the nanomanipulator and an optical fiber as the optical waveguide the nanoscale CdS/p-Si axial nanowire junctions were fabricated, and in situ photocurrents from them were successfully measured. Compared to a single constituting nanowire, the CdS/p-Si axial nanowire junctions possess a photocurrent saturation effect, which protects them from damage under high voltages. Furthermore, a set of experiments reveals the clear relationship between the saturation photocurrent values and the incident light intensities. The applied technique is expected to be valuable for bottom-up nanodevice fabrications, and the regarded photocurrent saturation feature may solve the Joule heating-induced failure problem in nanowire optoelectronic devices caused by a fluctuating bias.

  11. Atomic arrangement at ZnTe/CdSe interfaces determined by high resolution scanning transmission electron microscopy and atom probe tomography

    SciTech Connect

    Bonef, Bastien; Rouvière, Jean-Luc; Jouneau, Pierre-Henri; Bellet-Amalric, Edith; Gérard, Lionel; Mariette, Henri; André, Régis; Bougerol, Catherine; Grenier, Adeline

    2015-02-02

    High resolution scanning transmission electron microscopy and atom probe tomography experiments reveal the presence of an intermediate layer at the interface between two binary compounds with no common atom, namely, ZnTe and CdSe for samples grown by Molecular Beam Epitaxy under standard conditions. This thin transition layer, of the order of 1 to 3 atomic planes, contains typically one monolayer of ZnSe. Even if it occurs at each interface, the direct interface, i.e., ZnTe on CdSe, is sharper than the reverse one, where the ZnSe layer is likely surrounded by alloyed layers. On the other hand, a CdTe-like interface was never observed. This interface knowledge is crucial to properly design superlattices for optoelectronic applications and to master band-gap engineering.

  12. Direct Observation of the Layer-by-Layer Growth of ZnO Nanopillar by In situ High Resolution Transmission Electron Microscopy

    PubMed Central

    Li, Xing; Cheng, Shaobo; Deng, Shiqing; Wei, Xianlong; Zhu, Jing; Chen, Qing

    2017-01-01

    Catalyst-free methods are important for the fabrication of pure nanowires (NWs). However, the growth mechanism remains elusive due to the lack of crucial information on the growth dynamics at atomic level. Here, the noncatalytic growth process of ZnO NWs is studied through in situ high resolution transmission electron microscopy. We observe the layer-by-layer growth of ZnO nanopillars along the polar [0001] direction under electron beam irradiation, while no growth is observed along the radial directions, indicating an anisotropic growth mechanism. The source atoms are mainly from the electron beam induced damage of the sample and the growth is assisted by subsequent absorption and then diffusion of atoms along the side surface to the top (0002) surface. The different binding energy on different ZnO surface is the main origin for the anisotropic growth. Additionally, the coalescence of ZnO nanocrystals related to the nucleation stage is uncovered to realize through the rotational motions and recrystallization. Our in situ results provide atomic-level detailed information about the dynamic growth and coalescence processes in the noncatalytic synthesis of ZnO NW and are helpful for understanding the vapor-solid mechanism of catalyst-free NW growth. PMID:28098261

  13. Combining 2 nm Spatial Resolution and 0.02% Precision for Deformation Mapping of Semiconductor Specimens in a Transmission Electron Microscope by Precession Electron Diffraction.

    PubMed

    Cooper, David; Bernier, Nicolas; Rouvière, Jean-Luc

    2015-08-12

    Precession electron diffraction has been used to provide accurate deformation maps of a device structure showing that this technique can provide a spatial resolution of better than 2 nm and a precision of better than 0.02%. The deformation maps have been fitted to simulations that account for thin specimen relaxation. By combining the experimental deformation maps and simulations, we have been able to separate the effects of the stressor and recessed sources and drains and show that the Si3N4 stressor increases the in-plane deformation in the silicon channel from 0.92 to 1.52 ± 0.02%. In addition, the stress in the deposited Si3N4 film has been calculated from the simulations, which is an important parameter for device design.

  14. Determination of crystal growth rates during rapid solidification of polycrystalline aluminum by nano-scale spatio-temporal resolution in situ transmission electron microscopy

    SciTech Connect

    Zweiacker, K.; McKeown, J. T.; Liu, C.; LaGrange, T.; Reed, B. W.; Campbell, G. H.; Wiezorek, J. M. K.

    2016-08-04

    In situ investigations of rapid solidification in polycrystalline Al thin films were conducted using nano-scale spatio-temporal resolution dynamic transmission electron microscopy. Differences in crystal growth rates and asymmetries in melt pool development were observed as the heat extraction geometry was varied by controlling the proximity of the laser-pulse irradiation and the associated induced melt pools to the edge of the transmission electron microscopy support grid, which acts as a large heat sink. Experimental parameters have been established to maximize the reproducibility of the material response to the laser-pulse-related heating and to ensure that observations of the dynamical behavior of the metal are free from artifacts, leading to accurate interpretations and quantifiable measurements with improved precision. Interface migration rate measurements revealed solidification velocities that increased consistently from ~1.3 m s–1 to ~2.5 m s–1 during the rapid solidification process of the Al thin films. Under the influence of an additional large heat sink, increased crystal growth rates as high as 3.3 m s–1 have been measured. The in situ experiments also provided evidence for development of a partially melted, two-phase region prior to the onset of rapid solidification facilitated crystal growth. As a result, using the experimental observations and associated measurements as benchmarks, finite-element modeling based calculations of the melt pool evolution after pulsed laser irradiation have been performed to obtain estimates of the temperature evolution in the thin films.

  15. Determination of crystal growth rates during rapid solidification of polycrystalline aluminum by nano-scale spatio-temporal resolution in situ transmission electron microscopy

    DOE PAGES

    Zweiacker, K.; McKeown, J. T.; Liu, C.; ...

    2016-08-04

    In situ investigations of rapid solidification in polycrystalline Al thin films were conducted using nano-scale spatio-temporal resolution dynamic transmission electron microscopy. Differences in crystal growth rates and asymmetries in melt pool development were observed as the heat extraction geometry was varied by controlling the proximity of the laser-pulse irradiation and the associated induced melt pools to the edge of the transmission electron microscopy support grid, which acts as a large heat sink. Experimental parameters have been established to maximize the reproducibility of the material response to the laser-pulse-related heating and to ensure that observations of the dynamical behavior of themore » metal are free from artifacts, leading to accurate interpretations and quantifiable measurements with improved precision. Interface migration rate measurements revealed solidification velocities that increased consistently from ~1.3 m s–1 to ~2.5 m s–1 during the rapid solidification process of the Al thin films. Under the influence of an additional large heat sink, increased crystal growth rates as high as 3.3 m s–1 have been measured. The in situ experiments also provided evidence for development of a partially melted, two-phase region prior to the onset of rapid solidification facilitated crystal growth. As a result, using the experimental observations and associated measurements as benchmarks, finite-element modeling based calculations of the melt pool evolution after pulsed laser irradiation have been performed to obtain estimates of the temperature evolution in the thin films.« less

  16. Analysis of composition fluctuations on an atomic scale in Al0.25Ga0.75N by high-resolution transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Neubauer, B.; Rosenauer, A.; Gerthsen, D.; Ambacher, O.; Stutzmann, M.

    1998-08-01

    Composition fluctuations in the Al0.25Ga0.75N layer of an AlGaN/GaN transistor structure grown by plasma induced molecular beam epitaxy on Al2O3(0001) at a growth temperature of 870 °C were studied by digital analysis of lattice images (DALI) of high-resolution transmission electron microscopy (HRTEM) cross-section images. DALI exploits the linear dependence of the lattice parameters on the Al content by applying Vegard's law. Detecting the distances between intensity maxima positions in the micrograph which can be considered as a fingerprint of the local lattice parameters quantitatively derives composition profiles on an atomic scale. In the HRTEM cross-section image different areas were observed in the Al0.25Ga0.75N layer with either homogeneous or "striped" contrast. In the striped areas the analyses indicate a strong periodic decomposition with a period of 1 nm consisting of 1 ML Al0.8Ga0.2N and about 3 ML Al0.07Ga0.93N. The regions with homogeneous contrast do not exhibit significant composition fluctuations.

  17. Single grain analysis on a nanoscale in ZrO2:Al2O3 nano-composites by means of high-resolution scanning transmission electron Microscopy

    NASA Astrophysics Data System (ADS)

    Brossmann, Ulrich; Albu, Mihaela; Hofer, Ferdinand; Würschum, Roland

    2016-12-01

    Nano-particulate powders of Al2O3:ZrO2 composites and the pure constituents were prepared by microwave plasma process synthesis and studied by high resolution scanning transmission electron microscopy. The ZrO2:Al2O3 nanocomposite samples showed a structure of randomly arranged, crystalline grains of both ZrO2 and Al2O3 with a size in the range of 3-5 nm. For each constituent, both cubic and monoclinic grains were observed. Similarly prepared, single phase Al2O3 nanoparticles were found to be completely amorphous. In the case of ZrO2, the crystallite size and the fraction of the monoclinic ZrO2 phase is noticeably reduced in the ZrO2:Al2O3 nanocomposite in comparison to single phase samples. The observation of ultra-small crystalline Al2O3 in the composite samples, is tentatively ascribed to a modification of the interface energy by the contact of Al2O3 and ZrO2 as well as a possible uptake of ZrO2 into the Al2O3 grains from the gas phase during synthesis.

  18. Evidence for anisotropic dielectric properties of monoclinic hafnia using valence electron energy-loss spectroscopy in high-resolution transmission electron microscopy and ab initio time-dependent density-functional theory

    NASA Astrophysics Data System (ADS)

    Guedj, C.; Hung, L.; Zobelli, A.; Blaise, P.; Sottile, F.; Olevano, V.

    2014-12-01

    The effect of nanocrystal orientation on the energy loss spectra of monoclinic hafnia (m-HfO2) is measured by high resolution transmission electron microscopy (HRTEM) and valence energy loss spectroscopy (VEELS) on high quality samples. For the same momentum-transfer directions, the dielectric properties are also calculated ab initio by time-dependent density-functional theory (TDDFT). Experiments and simulations evidence anisotropy in the dielectric properties of m-HfO2, most notably with the direction-dependent oscillator strength of the main bulk plasmon. The anisotropic nature of m-HfO2 may contribute to the differences among VEELS spectra reported in literature. The good agreement between the complex dielectric permittivity extracted from VEELS with nanometer spatial resolution, TDDFT modeling, and past literature demonstrates that the present HRTEM-VEELS device-oriented methodology is a possible solution to the difficult nanocharacterization challenges given in the International Technology Roadmap for Semiconductors.

  19. Ponderomotive phase plate for transmission electron microscopes

    DOEpatents

    Reed, Bryan W [Livermore, CA

    2012-07-10

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

  20. Wavelet encoding and variable resolution progressive transmission

    NASA Technical Reports Server (NTRS)

    Blanford, Ronald P.

    1993-01-01

    Progressive transmission is a method of transmitting and displaying imagery in stages of successively improving quality. The subsampled lowpass image representations generated by a wavelet transformation suit this purpose well, but for best results the order of presentation is critical. Candidate data for transmission are best selected using dynamic prioritization criteria generated from image contents and viewer guidance. We show that wavelets are not only suitable but superior when used to encode data for progressive transmission at non-uniform resolutions. This application does not preclude additional compression using quantization of highpass coefficients, which to the contrary results in superior image approximations at low data rates.

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

    DOEpatents

    Brown, Jr., R. Malcolm; Barnes, Zack; Sawatari, Chie; Kondo, Tetsuo

    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.

  2. Aberration corrected Lorentz scanning transmission electron microscopy.

    PubMed

    McVitie, S; McGrouther, D; McFadzean, S; MacLaren, D A; O'Shea, K J; Benitez, M J

    2015-05-01

    We present results from an aberration corrected scanning transmission electron microscope which has been customised for high resolution quantitative Lorentz microscopy with the sample located in a magnetic field free or low field environment. We discuss the innovations in microscope instrumentation and additional hardware that underpin the imaging improvements in resolution and detection with a focus on developments in differential phase contrast microscopy. Examples from materials possessing nanometre scale variations in magnetisation illustrate the potential for aberration corrected Lorentz imaging as a tool to further our understanding of magnetism on this lengthscale.

  3. TEBAL: Nanosculpting devices with electrons in a transmission electron microscope

    NASA Astrophysics Data System (ADS)

    Drndic, Marija

    2008-03-01

    Manipulation of matter on the scale of atoms and molecules is an essential part of realizing the potential that nanotechnology has to offer. In this talk I will describe transmission electron beam ablation lithography (TEBAL), a method for fabricating nanostructures and fully integrated devices on silicon nitride membranes by nanosculpting evaporated metal films with electron beams. TEBAL works by controllably exposing materials to an intense and highly focused beam of 200 keV electrons inside the transmission electron microscope (TEM). The effect of electron irradiation can be used to controllably displace or ablate regions of the metal with resolution on the scale of tens of atoms per exposure. In situ TEM imaging of the ablation action with atomic resolution allows for real-time feedback control during fabrication. Specific examples presented here include the fabrication and characterization of nanogaps, nanorings, nanowires with tailored shapes and curvatures, and multi-terminal devices with nanoislands or nanopores between the terminals. These nanostructures are fabricated at precise locations on a chip and seamlessly integrated into large-scale circuitry. I will discuss how the combination of high resolution, geometrical control and yield make TEBAL attractive for many applications including nanoelectronics, superconductivity, nanofluidics and molecular (DNA) translocation studies through nanopore-based transistors. References: 1) M.D. Fischbein and M. Drndic, ``Sub-10 nm Device Fabrication in a Transmission Electron Microscope'', Nano Letters, 7 (5), 1329, 2007. 2) M. D. Fischbein and M. Drndic, ``Nanogaps by direct lithography for high-resolution imaging and electronic characterization of nanostructures'', Applied Physics Letters, 88 (6), 063116, 2006.

  4. Atmospheric pressure scanning transmission electron microscopy.

    PubMed

    de Jonge, Niels; Bigelow, Wilbur C; Veith, Gabriel M

    2010-03-10

    Scanning transmission electron microscope (STEM) images of gold nanoparticles at atmospheric pressure have been recorded through a 0.36 mm thick mixture of CO, O2, and He. This was accomplished using a reaction cell consisting of two electron-transparent silicon nitride membranes. Gold nanoparticles of a full width at half-maximum diameter of 1.0 nm were visible above the background noise, and the achieved edge resolution was 0.4 nm in accordance with calculations of the beam broadening.

  5. Large-volume reconstruction of brain tissue from high-resolution serial section images acquired by SEM-based scanning transmission electron microscopy.

    PubMed

    Kuwajima, Masaaki; Mendenhall, John M; Harris, Kristen M

    2013-01-01

    With recent improvements in instrumentation and computational tools, serial section electron microscopy has become increasingly straightforward. A new method for imaging ultrathin serial sections is developed based on a field emission scanning electron microscope fitted with a transmitted electron detector. This method is capable of automatically acquiring high-resolution serial images with a large field size and very little optical and physical distortions. In this chapter, we describe the procedures leading to the generation and analyses of a large-volume stack of high-resolution images (64 μm × 64 μm × 10 μm, or larger, at 2 nm pixel size), including how to obtain large-area serial sections of uniform thickness from well-preserved brain tissue that is rapidly perfusion-fixed with mixed aldehydes, processed with a microwave-enhanced method, and embedded into epoxy resin.

  6. Evolution of titania nanotubes-supported WO{sub x} species by in situ thermo-Raman spectroscopy, X-ray diffraction and high resolution transmission electron microscopy

    SciTech Connect

    Cortes-Jacome, M.A.; Angeles-Chavez, C.; Morales, M.; Lopez-Salinas, E.; Toledo-Antonio, J.A.

    2007-10-15

    Structural evolution of WO{sub x} species on the surface of titania nanotubes was followed by in situ thermo-Raman spectroscopy. A total of 15 wt% of W atoms were loaded on the surface of a hydroxylated titania nanotubes by impregnation with ammonium metatungstate solution and then, the sample was thermally treated in a Linkam cell at different temperatures in nitrogen flow. The band characteristic of the W=O bond was observed at 962 cm{sup -1} in the dried sample, which vanished between 300 and 700 deg. C, and reappear again after annealing at 800 deg. C, along with a broad band centered at 935 cm{sup -1}, attributed to the v{sub 1} vibration of W=O in tetrahedral coordination. At 900 and 1000 deg. C, the broad band decomposed into four bands at 923, 934, 940 and 950 cm{sup -1}, corresponding to the symmetric and asymmetric vibration of W=O bonds in Na{sub 2}WO{sub 4} and Na{sub 2}W{sub 2}O{sub 7} phases as determined by X-ray diffraction and High resolution transmission electron microscopy (HRTEM). The structure of the nanotubular support was kept at temperatures below 450 deg. C, thereafter, it transformed into anatase being stabilized at temperatures as high as 900 deg. C. At 1000 deg. C, anatase phase partially converted into rutile. After annealing at 1000 deg. C, a core-shell model material was obtained, with a shell of ca. 5 nm thickness, composed of sodium tungstate nanoclusters, and a core composed mainly of rutile TiO{sub 2} phase. - Graphical abstract: Titania nanotubes loaded with 15 wt% W atoms were characterized from room temperature (rt) to 1000 deg. C by thermo-Raman spectroscopy in N{sub 2}. At 1000 deg. C, a core-shell model material was obtained, with a shell thickness of ca. 5 nm composed by nanoclusters of sodium tungstate, and a core composed mainly of rutile TiO{sub 2} phase.

  7. Oxidation products of the niobium tungsten oxide Nb{sub 4}W{sub 13}O{sub 47}: A high-resolution scanning transmission electron microscopy study

    SciTech Connect

    Krumeich, Frank . E-mail: krumeich@inorg.chem.ethz.ch; Nesper, Reinhard

    2006-06-15

    Nb{sub 4}W{sub 13}O{sub 47}, a member of the solid solution series Nb{sub 8-n}W{sub 9+n}O{sub 47} (0=transmission electron microscopy applying a high-angle annular dark field detector. At the selected imaging conditions (Z contrast), not only the metal positions are revealed by this technique but valuable additional information about the elemental distribution can be obtained simultaneously.

  8. High-resolution three-dimensional scanning transmission electron microscopy characterization of oxide-nitride-oxide layer interfaces in Si-based semiconductors using computed tomography.

    PubMed

    Sadayama, Shoji; Sekiguchi, Hiromi; Bright, Alexander; Suzuki, Naohisa; Yamada, Kazuhiro; Kaneko, Kenji

    2011-01-01

    Oxide-nitride-oxide (ONO) layer structures are widely used for charge storage in flash memory devices. The ONO layer interfaces should be as flat as possible, so measurement of the nanoscale roughness of those interfaces is needed. In this study, quantification of an ONO film from a commercially available flash memory device was carried out with a pillar-shaped specimen using scanning transmission electron microscopy (STEM) and computed tomography. The ONO area contained only low Z- and low STEM-contrast materials, which makes high-quality reconstruction difficult. The optimum three-dimensional reconstruction was achieved with an STEM annular dark-field detector inner collection angle of 32 mrad, a sample tilt range from -78° to +78° and 25 iterations for the simultaneous iterative reconstruction technique.

  9. Low Resolution Picture Transmission (LRPT) Demonstration System

    NASA Technical Reports Server (NTRS)

    Fong, Wai; Yeh, Pen-Shu; Sank, Victor; Nyugen, Xuan; Xia, Wei; Duran, Steve; Day, John H. (Technical Monitor)

    2002-01-01

    Low-Resolution Picture Transmission (LRPT) is a proposed standard for direct broadcast transmission of satellite weather images. This standard is a joint effort by the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) and the National Oceanic Atmospheric Administration (NOAA). As a digital transmission scheme, its purpose is to replace the current analog Automatic Picture Transmission (APT) system for use in the Meteorological Operational (METOP) satellites. Goddard Space Flight Center has been tasked to build an LRPT Demonstration System (LDS). It's main objective is to develop or demonstrate the feasibility of a low-cost receiver utilizing a Personal Computer (PC) as the primary processing component and determine the performance of the protocol in the simulated Radio Frequency (RF) environment. The approach would consist of two phases. In the phase 1, a Commercial-off-the-Shelf (COTS) Modulator-Demodulator (MODEM) board that would perform RF demodulation would be purchased allowing the Central Processing Unit (CPU) to perform the Consultative Committee for Space Data Systems (CCSDS) protocol processing. Also since the weather images are compressed the PC would perform the decompression. Phase 1 was successfully demonstrated on December 1997. Phase 2 consists of developing a high-fidelity receiver, transmitter and environment simulator. Its goal is to find out how the METOP Specification performs in a simulated noise environment in a cost-effective receiver. The approach would be to produce a receiver using as much software as possible to perform front-end processing to take advantage of the latest high-speed PCs. Thus the COTS MODEM used in Phase 1 is performing RF demodulation along with data acquisition providing data to the receiving software. Also, environment simulator is produced using the noise patterns generated by Institute for Telecommunications Sciences (ITS) from their noise environment study.

  10. CONDENSED MATTER: STRUCTURE, THERMAL AND MECHANICAL PROPERTIES: High-resolution transmission electron microscopy and bulk magnetometry study of LaFe11.5Si1.5 compound

    NASA Astrophysics Data System (ADS)

    Zou, Jun-Ding; Li, Wei; Shen, Bao-Gen

    2009-10-01

    This paper studies the microstructural and magnetic properties of LaFe11.5Si1.5 compound by means of high-resolution transmission electron microscope and bulk magnetometry measurements. The crystalline structure is accompanied with the noncrystalline and nanocrystalline structures. This characteristic is the reflection of the crystalline process held by quenching. The inverse susceptibilities diverge and deviate from Curie-Weiss law under low applied magnetic fields. This paper proposes the possible mechanism between the anomalous susceptibilities and microstructure, and offers a perspective on the magnetic properties of metastable intermetallic compounds.

  11. Periodic cation segregation in Cs0.44[Nb2.54W2.46O14] quantified by high-resolution scanning transmission electron microscopy.

    PubMed

    Heidelmann, Markus; Barthel, Juri; Cox, Gerhard; Weirich, Thomas E

    2014-10-01

    The atomic structure of Cs0.44[Nb2.54W2.46O14] closely resembles the structure of the most active catalyst for the synthesis of acrylic acid, the M1 phase of Mo10V2(4+)Nb2TeO42-x. Consistently with observations made for the latter compound, the high-angle electron scattering signal recorded by scanning transmission electron microscopy shows a significant intensity variation, which repeats periodically with the projected crystallographic unit cell. The occupation factors for the individual mixed Nb/W atomic columns are extracted from the observed intensity variations. For this purpose, experimental images and simulated images are compared on an identical intensity scale, which enables a quantification of the cation distribution. According to our analysis specific sites possess low tungsten concentrations of 25%, whereas other sites have tungsten concentrations above 70%. These findings allow us to refine the existing structure model of the target compound, which has until now described a uniform distribution of the niobium and tungsten atoms in the unit cell, showing that the similarity between Cs0.44[Nb2.54W2.46O14] and the related catalytic compounds also extends to the level of the cation segregation.

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

    PubMed

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

    2012-12-01

    Some four decades were needed to catch up with the vision that Albert Crewe and his group had for the scanning transmission electron microscope (STEM) in the nineteen sixties and seventies: attaining 0.5Å resolution, and identifying single atoms spectroscopically. With these goals now attained, STEM developments are turning toward new directions, such as rapid atomic resolution imaging and exploring atomic bonding and electronic properties of samples at atomic resolution. The accomplishments and the future challenges are reviewed and illustrated with practical examples.

  13. Transmission electron microscope CCD camera

    DOEpatents

    Downing, Kenneth H.

    1999-01-01

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

  14. Sub-10 nm device fabrication in a transmission electron microscope.

    PubMed

    Fischbein, Michael D; Drndić, Marija

    2007-05-01

    We show that a high-resolution transmission electron microscope can be used to fabricate metal nanostructures and devices on insulating membranes by nanosculpting metal films. Fabricated devices include nanogaps, nanodiscs, nanorings, nanochannels, and nanowires with tailored curvatures and multi-terminal nanogap devices with nanoislands or nanoholes between the terminals. The high resolution, geometrical flexibility, and yield make this fabrication method attractive for many applications including nanoelectronics and nanofluidics.

  15. Super-Resolution Image Reconstruction by Nonlocal Means Applied to High-Angle Annular Darkfield Scanning Transmission Electron Microscopy (HAADF-STEM)

    DTIC Science & Technology

    2009-10-06

    When talking about superresolution we always mean to recover the level of resolution set by the microscope, but by using a time series of low...on low resolution possibly very noisy data, is not feasible. Thus, standard superresolution concepts as described above that are based on registration

  16. Quantification of the Information Limit of Transmission Electron Microscopes

    SciTech Connect

    Barthel, J.; Thust, A.

    2008-11-14

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

  17. Direct observations of atomic diffusion by scanning transmission electron microscopy

    PubMed Central

    Isaacson, M.; Kopf, D.; Utlaut, M.; Parker, N. W.; Crewe, A. V.

    1977-01-01

    The feasibility of using a high-resolution scanning transmission electron microscope to study the diffusion of heavy atoms on thin film substrates of low atomic number has been investigated. We have shown that it is possible to visualize the diffusion of individual uranium atoms adsorbed to thin carbon film substrates and that the observed motion of the atoms does not appear to be induced by the incident electron beam. Images PMID:16592396

  18. Component analyses of urinary nanocrystallites of uric acid stone formers by combination of high-resolution transmission electron microscopy, fast Fourier transformation, energy dispersive X-ray spectroscopy, X-ray diffraction and Fourier transform infrared spectroscopy.

    PubMed

    Sun, Xin-Yuan; Xue, Jun-Fa; Xia, Zhi-Yue; Ouyang, Jian-Ming

    2015-06-01

    This study aimed to analyse the components of nanocrystallites in urines of patients with uric acid (UA) stones. X-ray diffraction (XRD), Fourier transform infrared spectroscopy, high-resolution transmission electron microscopy (HRTEM), fast Fourier transformation (FFT) of HRTEM, and energy dispersive X-ray spectroscopy (EDS) were performed to analyse the components of these nanocrystallites. XRD and FFT showed that the main component of urinary nanocrystallites was UA, which contains a small amount of calcium oxalate monohydrate and phosphates. EDS showed the characteristic absorption peaks of C, O, Ca and P. The formation of UA stones was closely related to a large number of UA nanocrystallites in urine. A combination of HRTEM, FFT, EDS and XRD analyses could be performed accurately to analyse the components of urinary nanocrystallites.

  19. Improved methods for high resolution electron microscopy

    SciTech Connect

    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.

  20. Improved methods for high resolution electron microscopy

    NASA Astrophysics Data System (ADS)

    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 C44H90 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.

  1. High-resolution electron microscopy of advanced materials

    SciTech Connect

    Mitchell, T.E.; Kung, H.H.; Sickafus, K.E.; Gray, G.T. III; Field, R.D.; Smith, J.F.

    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.

  2. Sunrise over Mars - electronic transmission

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Caption: 'Taken during the Viking Orbiter 1's 40th revolution of Mars, this electronically transmitted image shows sunrise over the tributary canyons of a high plateau region. The white areas are bright clouds of water ice.' As the sun rises over Noctis Labryinthus (the labyrinth of the night), bright clouds of water ice can be observed in and around the tributary canyons of this high plateau region of Mars. This color composite image, reconstructed from three individual black and white frames taken through violet, green, and orange filters, vividly shows the distribution of the clouds against the rust colored background of this Martian desert. The picture was reconstructed by JPL's Image Processing Laboratory using in-flight calibration data to correct the color balance. Scientists have puzzled why the clouds cling to the canyon areas and, only in certain areas, spill over onto the plateau surface. One possibility is that water which condensed during the previous afternoon in shaded eastern-facing slopes of the canyon floor is vaporized as the early morning sun falls on those same slopes. The area covered is about 10,000 square kilometers (4000 square miles), centered at 9 degrees South, 95 degrees West, and the large partial crater at lower right is Oudemans. The picture was taken on Viking Orbiter 1's 40th revolution of the planet. Photograph and caption published in Winds of Change, 75th Anniversary NASA publication (pages 108-109), by James Schultz.

  3. Cryo-scanning transmission electron tomography of vitrified cells.

    PubMed

    Wolf, Sharon Grayer; Houben, Lothar; Elbaum, Michael

    2014-04-01

    Cryo-electron tomography (CET) of fully hydrated, vitrified biological specimens has emerged as a vital tool for biological research. For cellular studies, the conventional imaging modality of transmission electron microscopy places stringent constraints on sample thickness because of its dependence on phase coherence for contrast generation. Here we demonstrate the feasibility of using scanning transmission electron microscopy for cryo-tomography of unstained vitrified specimens (CSTET). We compare CSTET and CET for the imaging of whole bacteria and human tissue culture cells, finding favorable contrast and detail in the CSTET reconstructions. Particularly at high sample tilts, the CSTET signals contain more informative data than energy-filtered CET phase contrast images, resulting in improved depth resolution. Careful control over dose delivery permits relatively high cumulative exposures before the onset of observable beam damage. The increase in acceptable specimen thickness broadens the applicability of electron cryo-tomography.

  4. In situ formation of bismuth nanoparticles through electron-beam irradiation in a transmission electron microscope

    NASA Astrophysics Data System (ADS)

    Sepulveda-Guzman, S.; Elizondo-Villarreal, N.; Ferrer, D.; Torres-Castro, A.; Gao, X.; Zhou, J. P.; Jose-Yacaman, M.

    2007-08-01

    In this work, bismuth nanoparticles were synthesized when a precursor, sodium bismuthate, was exposed to an electron beam at room temperature in a transmission electron microscope (TEM). The irradiation effects were investigated in situ using selected-area electron diffraction, high-resolution transmission electron microscopy and x-ray energy dispersive spectroscopy. After the electron irradiation, bismuth nanoparticles with a rhombohedral structure and diameter of 6 nm were observed. The average particle size increased with the irradiation time. The electron-induced reduction is attributed to the desorption of oxygen ions. This method offers a one-step route to synthesize bismuth nanoparticles using electron irradiation, and the particle size can be controlled by the irradiation time.

  5. Extreme ultraviolet spectrometer based on a transmission electron microscopy grid

    DOE PAGES

    Sistrunk, Emily; Gühr, Markus

    2014-12-12

    Here, we performed extreme ultraviolet spectroscopy using an 80 lines/mm transmission electron microscope mesh as the dispersive element. We also present the usefulness of this instrument for dispersing a high harmonic spectrum from the 13th to the 29th harmonic of a Ti:sapph laser, corresponding to a wavelength range from 60 to 27 nm. The resolution of the instrument is limited by the image size of the high harmonic generation region on the detector. Finally, the resolution in first order diffraction is under 2 nm over the entire spectral range with a resolving power around 30.

  6. Coherent Chromatic Effect in the Transmission Electron Microscope

    NASA Astrophysics Data System (ADS)

    Erni, Rolf

    2016-03-01

    Under the assumption of local atomic scattering, elastic electron scattering at finite scattering angles implies a small but finite energy loss. This energy loss, which under conventional imaging conditions in high-resolution transmission electron microscopy is of the order of 0.1 meV and thus negligible, increases by more than 2 orders of magnitude if light elements are investigated at sub-Ångström resolution. For a microscope of finite chromatic aberration, the energy loss leads to an element-specific chromatic effect which increases with the instrument resolution and with decreasing mass of the scattering atom. Despite that this effect is small, it can degrade the achievable image contrast. However, the effect can be considered in the optimization of the phase-contrast imaging conditions and even be beneficial to enhance the relative image contrast of light atoms in the presence of heavy atoms.

  7. Coherent Chromatic Effect in the Transmission Electron Microscope.

    PubMed

    Erni, Rolf

    2016-03-18

    Under the assumption of local atomic scattering, elastic electron scattering at finite scattering angles implies a small but finite energy loss. This energy loss, which under conventional imaging conditions in high-resolution transmission electron microscopy is of the order of 0.1 meV and thus negligible, increases by more than 2 orders of magnitude if light elements are investigated at sub-Ångström resolution. For a microscope of finite chromatic aberration, the energy loss leads to an element-specific chromatic effect which increases with the instrument resolution and with decreasing mass of the scattering atom. Despite that this effect is small, it can degrade the achievable image contrast. However, the effect can be considered in the optimization of the phase-contrast imaging conditions and even be beneficial to enhance the relative image contrast of light atoms in the presence of heavy atoms.

  8. Three-dimensional scanning transmission electron microscopy of biological specimens

    SciTech Connect

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

    2010-01-01

    A three-dimensional (3D) reconstruction of the cytoskeleton and a clathrin-coated pit in mammalian cells has been achieved from a focal-series of images recorded in an aberration-corrected scanning transmission electron microscope (STEM). The specimen was a metallic replica of the biological structure comprising Pt nanoparticles 2 - 3 nm in diameter, with a high stability under electron beam radiation. The 3D dataset was processed by an automated deconvolution procedure. The lateral resolution was 1.1 nm, set by pixel size. Particles differing by only 10 nm in vertical position were identified as separate objects with greater than 20% dip in contrast between them. We refer to this value as the axial resolution of the deconvolution or reconstruction, the ability to recognize two objects, which were unresolved in the original data set. The precision of the height determination was 0.2 nm. The resolution of the reconstruction is comparable to that achieved by tilt-series transmission electron microscopy (TEM). However, the focal-series method does not require mechanical tilting and is therefore much faster. 3D STEM images were also recorded of the Golgi ribbon in conventional thin sections containing 3T3 cells with a comparable axial resolution in the deconvolved data set.

  9. Three-dimensional scanning transmission electron microscopy of biological specimens.

    PubMed

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

    2010-02-01

    A three-dimensional (3D) reconstruction of the cytoskeleton and a clathrin-coated pit in mammalian cells has been achieved from a focal-series of images recorded in an aberration-corrected scanning transmission electron microscope (STEM). The specimen was a metallic replica of the biological structure comprising Pt nanoparticles 2-3 nm in diameter, with a high stability under electron beam radiation. The 3D dataset was processed by an automated deconvolution procedure. The lateral resolution was 1.1 nm, set by pixel size. Particles differing by only 10 nm in vertical position were identified as separate objects with greater than 20% dip in contrast between them. We refer to this value as the axial resolution of the deconvolution or reconstruction, the ability to recognize two objects, which were unresolved in the original dataset. The resolution of the reconstruction is comparable to that achieved by tilt-series transmission electron microscopy. However, the focal-series method does not require mechanical tilting and is therefore much faster. 3D STEM images were also recorded of the Golgi ribbon in conventional thin sections containing 3T3 cells with a comparable axial resolution in the deconvolved dataset.

  10. Transmission Electron Microscope Measures Lattice Parameters

    NASA Technical Reports Server (NTRS)

    Pike, William T.

    1996-01-01

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

  11. Atomic resolution 3D electron diffraction microscopy

    SciTech Connect

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

    2002-03-01

    Electron lens aberration is the major barrier limiting the resolution of electron microscopy. Here we describe a novel form of electron microscopy to overcome electron lens aberration. By combining coherent electron diffraction with the oversampling phasing method, we show that the 3D structure of a 2 x 2 x 2 unit cell nano-crystal (framework of LTA [Al12Si12O48]8) can be ab initio determined at the resolution of 1 Angstrom from a series of simulated noisy diffraction pattern projections with rotation angles ranging from -70 degrees to +70 degrees in 5 degrees increments along a single rotation axis. This form of microscopy (which we call 3D electron diffraction microscopy) does not require any reference waves, and can image the 3D structure of nanocrystals, as well as non-crystalline biological and materials science samples, with the resolution limited only by the quality of sample diffraction.

  12. High resolution transmission electron microscopy of aluminophosphates

    SciTech Connect

    Ulan, J.G.; Gronsky, R. ); Szostak, R. ); Sorby, K. . Dept. of Chemistry)

    1990-04-01

    VPI-5 transforms to AlPO{sub 4}-8 under mild thermal treatment (100{degree}C, 18 hrs). HRTEM micrographs, oriented normal to the c axis, show extensive defect-free regions in VPI-5, while slip planes normal to the c axis are found in AlPO{sub 4}-8. Analysis of the HRTEM data, in conjunction with infrared and thermal analysis, adsorption studies and x-ray powder diffraction, has lead to a proposed structure for AlPO{sub 4}-8. Though the sheets containing the 18 member rings which define the pores in VPI-5 remain intact in AlPO{sub 4}-8, reduction in the porosity is attributed to blockages created by the movement of these sheets relative to each other. 8 refs., 7 figs.

  13. Concurrent in situ ion irradiation transmission electron microscope

    DOE PAGES

    Hattar, K.; Bufford, D. C.; Buller, D. L.

    2014-08-29

    An in situ ion irradiation transmission electron microscope has been developed and is operational at Sandia National Laboratories. This facility permits high spatial resolution, real time observation of electron transparent samples under ion irradiation, implantation, mechanical loading, corrosive environments, and combinations thereof. This includes the simultaneous implantation of low-energy gas ions (0.8–30 keV) during high-energy heavy ion irradiation (0.8–48 MeV). In addition, initial results in polycrystalline gold foils are provided to demonstrate the range of capabilities.

  14. Introduction to high-resolution cryo-electron microscopy.

    PubMed

    Czarnocki-Cieciura, Mariusz; Nowotny, Marcin

    2016-01-01

    For many years two techniques have dominated structural biology - X-ray crystallography and NMR spectroscopy. Traditional cryo-electron microscopy of biological macromolecules produced macromolecular reconstructions at resolution limited to 6-10 Å. Recent development of transmission electron microscopes, in particular the development of direct electron detectors, and continuous improvements in the available software, have led to the "resolution revolution" in cryo-EM. It is now possible to routinely obtain near-atomic-resolution 3D maps of intact biological macromolecules as small as ~100 kDa. Thus, cryo-EM is now becoming the method of choice for structural analysis of many complex assemblies that are unsuitable for structure determination by other methods.

  15. 7 CFR 400.209 - Electronic transmission and receiving system.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 6 2013-01-01 2013-01-01 false Electronic transmission and receiving system. 400.209... Contract-Standards for Approval § 400.209 Electronic transmission and receiving system. Any Contractor... Corporation approval of the electronic system as a condition to the electronic transmission and reception...

  16. 7 CFR 400.209 - Electronic transmission and receiving system.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 6 2014-01-01 2014-01-01 false Electronic transmission and receiving system. 400.209... Contract-Standards for Approval § 400.209 Electronic transmission and receiving system. Any Contractor... Corporation approval of the electronic system as a condition to the electronic transmission and reception...

  17. 7 CFR 400.209 - Electronic transmission and receiving system.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 6 2012-01-01 2012-01-01 false Electronic transmission and receiving system. 400.209... Contract-Standards for Approval § 400.209 Electronic transmission and receiving system. Any Contractor... Corporation approval of the electronic system as a condition to the electronic transmission and reception...

  18. 7 CFR 400.209 - Electronic transmission and receiving system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Electronic transmission and receiving system. 400.209... Contract-Standards for Approval § 400.209 Electronic transmission and receiving system. Any Contractor... Corporation approval of the electronic system as a condition to the electronic transmission and reception...

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

    PubMed

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

    2014-09-01

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

  20. Transmission Electron Microscopy of Itokawa Regolith Grains

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  1. Phase-contrast scanning transmission electron microscopy.

    PubMed

    Minoda, Hiroki; Tamai, Takayuki; Iijima, Hirofumi; Hosokawa, Fumio; Kondo, Yukihito

    2015-06-01

    This report introduces the first results obtained using phase-contrast scanning transmission electron microscopy (P-STEM). A carbon-film phase plate (PP) with a small center hole is placed in the condenser aperture plane so that a phase shift is introduced in the incident electron waves except those passing through the center hole. A cosine-type phase-contrast transfer function emerges when the phase-shifted scattered waves interfere with the non-phase-shifted unscattered waves, which passed through the center hole before incidence onto the specimen. The phase contrast resulting in P-STEM is optically identical to that in phase-contrast transmission electron microscopy that is used to provide high contrast for weak phase objects. Therefore, the use of PPs can enhance the phase contrast of the STEM images of specimens in principle. The phase shift resulting from the PP, whose thickness corresponds to a phase shift of π, has been confirmed using interference fringes displayed in the Ronchigram of a silicon single crystal specimen. The interference fringes were found to abruptly shift at the edge of the PP hole by π.

  2. Transmission electron microscopy of electrospun GaN nanofibers

    NASA Astrophysics Data System (ADS)

    Robles-García, Joshua L.; Meléndez, Anamaris; Yates, Douglas; Santiago-Avilés, Jorge J.; Ramos, Idalia; Campo, Eva M.

    2011-06-01

    We have reported earlier progress in producing polycrystalline wurtzite-polymorph and photo-conductive GaN nanofibers by electrospinning. This paper shows grain stacking during heat treatment and suggests the need to understand nucleation and grain growth following electrospinning. Transmission Electron Microscopy (TEM) analysis of GaN shows brittle fibers, grain stacking, and unfinished grain nucleation. X-Ray Diffraction analysis confirmed dominant hexagonal 101-wurtzite preferential overall orientation and the incipient grains are of high crystalline quality as seen by high resolution TEM.

  3. Transmission electron microscopy study of flea lymph cell thin sections

    NASA Astrophysics Data System (ADS)

    Volkov, Uryi P.; Konnov, Nikolai P.; Novikova, Olga V.

    2002-07-01

    Transmission electron microscopy investigation of thin sections remains the major method of cells inner structure study with high resolution. However, the present-day technique of cells preparation make it impossible to study a number of biological samples, such as very small quantity of lymph cells of little insects. A new technique of cells preparation has been developed in our lab, which allows to obtain a thin sections of ultra small quantity of cells. Structure of lymph cells of flea was investigated by the technique.

  4. Time Resolved Phase Transitions via Dynamic Transmission Electron Microscopy

    SciTech Connect

    Reed, B W; Armstrong, M R; Blobaum, K J; Browning, N D; Burnham, A K; Campbell, G H; Gee, R; Kim, J S; King, W E; Maiti, A; Piggott, W T; Torralva, B R

    2007-02-22

    The Dynamic Transmission Electron Microscope (DTEM) project is developing an in situ electron microscope with nanometer- and nanosecond-scale resolution for the study of rapid laser-driven processes in materials. We report on the results obtained in a year-long LDRD-supported effort to develop DTEM techniques and results for phase transitions in molecular crystals, reactive multilayer foils, and melting and resolidification of bismuth. We report the first in situ TEM observation of the HMX {beta}-{delta} phase transformation in sub-{micro}m crystals, computational results suggesting the importance of voids and free surfaces in the HMX transformation kinetics, and the first electron diffraction patterns of intermediate states in fast multilayer foil reactions. This project developed techniques which are applicable to many materials systems and will continue to be employed within the larger DTEM effort.

  5. Pulsed Power for a Dynamic Transmission Electron Microscope

    SciTech Connect

    dehope, w j; browning, n; campbell, g; cook, e; king, w; lagrange, t; reed, b; stuart, b; Shuttlesworth, R; Pyke, B

    2009-06-25

    Lawrence Livermore National Laboratory (LLNL) has converted a commercial 200kV transmission electron microscope (TEM) into an ultrafast, nanoscale diagnostic tool for material science studies. The resulting Dynamic Transmission Electron Microscope (DTEM) has provided a unique tool for the study of material phase transitions, reaction front analyses, and other studies in the fields of chemistry, materials science, and biology. The TEM's thermionic electron emission source was replaced with a fast photocathode and a laser beam path was provided for ultraviolet surface illumination. The resulting photoelectron beam gives downstream images of 2 and 20 ns exposure times at 100 and 10 nm spatial resolution. A separate laser, used as a pump pulse, is used to heat, ignite, or shock samples while the photocathode electron pulses, carefully time-synchronized with the pump, function as probe in fast transient studies. The device functions in both imaging and diffraction modes. A laser upgrade is underway to make arbitrary cathode pulse trains of variable pulse width of 10-1000 ns. Along with a fast e-beam deflection scheme, a 'movie mode' capability will be added to this unique diagnostic tool. This talk will review conventional electron microscopy and its limitations, discuss the development and capabilities of DTEM, in particularly addressing the prime and pulsed power considerations in the design and fabrication of the DTEM, and conclude with the presentation of a deflector and solid-state pulser design for Movie-Mode DTEM.

  6. Nonlinear transmission line based electron beam driver

    SciTech Connect

    French, David M.; Hoff, Brad W.; Tang Wilkin; Heidger, Susan; Shiffler, Don; Allen-Flowers, Jordan

    2012-12-15

    Gated field emission cathodes can provide short electron pulses without the requirement of laser systems or cathode heating required by photoemission or thermionic cathodes. The large electric field requirement for field emission to take place can be achieved by using a high aspect ratio cathode with a large field enhancement factor which reduces the voltage requirement for emission. In this paper, a cathode gate driver based on the output pulse train from a nonlinear transmission line is experimentally demonstrated. The application of the pulse train to a tufted carbon fiber field emission cathode generates short electron pulses. The pulses are approximately 2 ns in duration with emission currents of several mA, and the train contains up to 6 pulses at a frequency of 100 MHz. Particle-in-cell simulation is used to predict the characteristic of the current pulse train generated from a single carbon fiber field emission cathode using the same technique.

  7. Photocathode Optimization for a Dynamic Transmission Electron Microscope: Final Report

    SciTech Connect

    Ellis, P; Flom, Z; Heinselman, K; Nguyen, T; Tung, S; Haskell, R; Reed, B W; LaGrange, T

    2011-08-04

    The Dynamic Transmission Electron Microscope (DTEM) team at Harvey Mudd College has been sponsored by LLNL to design and build a test setup for optimizing the performance of the DTEM's electron source. Unlike a traditional TEM, the DTEM achieves much faster exposure times by using photoemission from a photocathode to produce electrons for imaging. The DTEM team's work is motivated by the need to improve the coherence and current density of the electron cloud produced by the electron gun in order to increase the image resolution and contrast achievable by DTEM. The photoemission test setup is nearly complete and the team will soon complete baseline tests of electron gun performance. The photoemission laser and high voltage power supply have been repaired; the optics path for relaying the laser to the photocathode has been finalized, assembled, and aligned; the internal setup of the vacuum chamber has been finalized and mostly implemented; and system control, synchronization, and data acquisition has been implemented in LabVIEW. Immediate future work includes determining a consistent alignment procedure to place the laser waist on the photocathode, and taking baseline performance measurements of the tantalum photocathode. Future research will examine the performance of the electron gun as a function of the photoemission laser profile, the photocathode material, and the geometry and voltages of the accelerating and focusing components in the electron gun. This report presents the team's progress and outlines the work that remains.

  8. Electronic automatic gear transmission control apparatus

    SciTech Connect

    Koshizawa, T.

    1989-04-25

    This patent describes an electronic automatic gear transmission control apparatus having a shift schedule map for commanding an optimum gear position based on a vehicle speed signal and an accelerator opening signal, the electronic automatic gear transmission control apparatus comprising: first means for comparing a gear position commanded by the shift schedule map with a present gear position; second means for effecting a gear shift to a gear position which is one gear position higher than the present gear position and for restraining a gear shift to the commanded gear position for a prescribed period of time, if the commanded gear position requires an upshift to a gear position which is two or more gear positions higher than the present gear position as a result of the comparison performed by the first means; and third means for holding the gear position which is one gear position higher than the present gear position until an accelerator pedal is depressed again, when the accelerator opening signal indicates an idling position while the gear shift up to the gear position which is one gear position higher than the present gear position, is being effected by the second means.

  9. Phase contrast in high resolution electron microscopy

    DOEpatents

    Rose, H.H.

    1975-09-23

    This patent relates to a device for developing a phase contrast signal for a scanning transmission electron microscope. The lens system of the microscope is operated in a condition of defocus so that predictable alternate concentric regions of high and low electron density exist in the cone of illumination. Two phase detectors are placed beneath the object inside the cone of illumination, with the first detector having the form of a zone plate, each of its rings covering alternate regions of either higher or lower electron density. The second detector is so configured that it covers the regions of electron density not covered by the first detector. Each detector measures the number of electrons incident thereon and the signal developed by the first detector is subtracted from the signal developed by the record detector to provide a phase contrast signal. (auth)

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

    SciTech Connect

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

    2003-09-01

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

  11. Sub-ångstrom resolution using aberration corrected electron optics

    NASA Astrophysics Data System (ADS)

    Batson, P. E.; Dellby, N.; Krivanek, O. L.

    2002-08-01

    Following the invention of electron optics during the 1930s, lens aberrations have limited the achievable spatial resolution to about 50 times the wavelength of the imaging electrons. This situation is similar to that faced by Leeuwenhoek in the seventeenth century, whose work to improve the quality of glass lenses led directly to his discovery of the ubiquitous ``animalcules'' in canal water, the first hints of the cellular basis of life. The electron optical aberration problem was well understood from the start, but more than 60 years elapsed before a practical correction scheme for electron microscopy was demonstrated, and even then the remaining chromatic aberrations still limited the resolution. We report here the implementation of a computer-controlled aberration correction system in a scanning transmission electron microscope, which is less sensitive to chromatic aberration. Using this approach, we achieve an electron probe smaller than 1Å. This performance, about 20 times the electron wavelength at 120keV energy, allows dynamic imaging of single atoms, clusters of a few atoms, and single atomic layer `rafts' of atoms coexisting with Au islands on a carbon substrate. This technique should also allow atomic column imaging of semiconductors, for detection of single dopant atoms, using an electron beam with energy below the damage threshold for silicon.

  12. Computer synthesis of high resolution electron micrographs

    NASA Technical Reports Server (NTRS)

    Nathan, R.

    1976-01-01

    Specimen damage, spherical aberration, low contrast and noisy sensors combine to prevent direct atomic viewing in a conventional electron microscope. The paper describes two methods for obtaining ultra-high resolution in biological specimens under the electron microscope. The first method assumes the physical limits of the electron objective lens and uses a series of dark field images of biological crystals to obtain direct information on the phases of the Fourier diffraction maxima; this information is used in an appropriate computer to synthesize a large aperture lens for a 1-A resolution. The second method assumes there is sufficient amplitude scatter from images recorded in focus which can be utilized with a sensitive densitometer and computer contrast stretching to yield fine structure image details. Cancer virus characterization is discussed as an illustrative example. Numerous photographs supplement the text.

  13. Characterization of nanomaterials with transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Anjum, D. H.

    2016-08-01

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

  14. Electron microscopy of gold nanoparticles at atomic resolution

    PubMed Central

    Azubel, Maia; Koivisto, Jaakko; Malola, Sami; Bushnell, David; Hura, Greg L.; Koh, Ai Leen; Tsunoyama, Hironori; Tsukuda, Tatsuya; Pettersson, Mika; Häkkinen, Hannu; Kornberg, Roger D.

    2014-01-01

    Structure determination of gold nanoparticles (AuNPs) is necessary for understanding their physical and chemical properties, and only one AuNP larger than 1 nm in diameter, an Au102NP, has been solved to atomic resolution. Whereas the Au102NP structure was determined by X-ray crystallography, other large AuNPs have proved refractory to this approach. Here we report the structure determination of an Au68NP at atomic resolution by aberration-corrected transmission electron microscopy (AC-TEM), performed with the use of a minimal electron dose, an approach that should prove applicable to metal NPs in general. The structure of the Au68NP was supported by small angle X-ray scattering (SAXS) and by comparison of observed infrared (IR) absorption spectra with calculations by density functional theory (DFT). PMID:25146285

  15. Nanoparticle imaging. Electron microscopy of gold nanoparticles at atomic resolution.

    PubMed

    Azubel, Maia; Koivisto, Jaakko; Malola, Sami; Bushnell, David; Hura, Greg L; Koh, Ai Leen; Tsunoyama, Hironori; Tsukuda, Tatsuya; Pettersson, Mika; Häkkinen, Hannu; Kornberg, Roger D

    2014-08-22

    Structure determination of gold nanoparticles (AuNPs) is necessary for understanding their physical and chemical properties, but only one AuNP larger than 1 nanometer in diameter [a 102-gold atom NP (Au102NP)] has been solved to atomic resolution. Whereas the Au102NP structure was determined by x-ray crystallography, other large AuNPs have proved refractory to this approach. Here, we report the structure determination of a Au68NP at atomic resolution by aberration-corrected transmission electron microscopy, performed with the use of a minimal electron dose, an approach that should prove applicable to metal NPs in general. The structure of the Au68NP was supported by small-angle x-ray scattering and by comparison of observed infrared absorption spectra with calculations by density functional theory.

  16. Atomic resolution electron microscopy of small metal clusters

    NASA Astrophysics Data System (ADS)

    Bovin, J.-O.; Malm, J.-O.

    1991-03-01

    Atomic resolution imaging of cluster structures has been performed with high resolution transmission electron microscopy (HRTEM). Metal particles of the sizes 1 nanometer to tens of nanometers have been surface profile imaged on different supports; like zeolites, cordierite and amorphous carbon. It is shown that organic ligands in Schmid-clusters coordinated to the metal surface are desorbed or destroyed by the electron beam. Dynamic events on the surfaces and in the bulk of small metal particles have been recorded for small crystals of Au, Pt, Rh and Pb and can be classified under three headings; The smaller the crystals are the faster rearrangements of the crystal structure; “clouds” of atoms existing outside some surfaces are involved in extensive structural rearrangements of the surface or crystal surface growth; localized atom hopping on surfaces during crystal growth and desorption also occurs.

  17. Data processing for atomic resolution electron energy loss spectroscopy.

    PubMed

    Cueva, Paul; Hovden, Robert; Mundy, Julia A; Xin, Huolin L; Muller, David A

    2012-08-01

    The high beam current and subangstrom resolution of aberration-corrected scanning transmission electron microscopes has enabled electron energy loss spectroscopy (EELS) mapping with atomic resolution. These spectral maps are often dose limited and spatially oversampled, leading to low counts/channel and are thus highly sensitive to errors in background estimation. However, by taking advantage of redundancy in the dataset map, one can improve background estimation and increase chemical sensitivity. We consider two such approaches--linear combination of power laws and local background averaging--that reduce background error and improve signal extraction. Principal component analysis (PCA) can also be used to analyze spectrum images, but the poor peak-to-background ratio in EELS can lead to serious artifacts if raw EELS data are PCA filtered. We identify common artifacts and discuss alternative approaches. These algorithms are implemented within the Cornell Spectrum Imager, an open source software package for spectroscopic analysis.

  18. Combined Scanning Transmission Electron Microscopy Tilt- and Focal Series

    SciTech Connect

    Dahmen, Tim; Baudoin, Jean-Pierre G; Lupini, Andrew R; Kubel, Christian; Slusallek, Phillip; De Jonge, Niels

    2014-01-01

    In this study, a combined tilt- and focal series is proposed as a new recording scheme for high-angle annular dark-field scanning transmission electron microscopy (STEM) tomography. Three-dimensional (3D) data were acquired by mechanically tilting the specimen, and recording a through-focal series at each tilt direction. The sample was a whole-mount macrophage cell with embedded gold nanoparticles. The tilt focal algebraic reconstruction technique (TF-ART) is introduced as a new algorithm to reconstruct tomograms from such combined tilt- and focal series. The feasibility of TF-ART was demonstrated by 3D reconstruction of the experimental 3D data. The results were compared with a conventional STEM tilt series of a similar sample. The combined tilt- and focal series led to smaller missing wedge artifacts, and a higher axial resolution than obtained for the STEM tilt series, thus improving on one of the main issues of tilt series-based electron tomography.

  19. Scanning transmission electron microscopy strain measurement from millisecond frames of a direct electron charge coupled device

    SciTech Connect

    Mueller, Knut; Rosenauer, Andreas; Ryll, Henning; Ordavo, Ivan; Ihle, Sebastian; Soltau, Heike; Strueder, Lothar; Volz, Kerstin; Zweck, Josef

    2012-11-19

    A high-speed direct electron detection system is introduced to the field of transmission electron microscopy and applied to strain measurements in semiconductor nanostructures. In particular, a focused electron probe with a diameter of 0.5 nm was scanned over a fourfold quantum layer stack with alternating compressive and tensile strain and diffracted discs have been recorded on a scintillator-free direct electron detector with a frame time of 1 ms. We show that the applied algorithms can accurately detect Bragg beam positions despite a significant point spread each 300 kV electron causes during detection on the scintillator-free camera. For millisecond exposures, we find that strain can be measured with a precision of 1.3 Multiplication-Sign 10{sup -3}, enabling, e.g., strain mapping in a 100 Multiplication-Sign 100 nm{sup 2} region with 0.5 nm resolution in 40 s.

  20. Observation of a vacuum tunnel gap in a transmission electron microscope using a micromechanical tunneling microscope

    NASA Astrophysics Data System (ADS)

    Lutwyche, M. I.; Wada, Y.

    1995-05-01

    This letter reports the observation of the vacuum tunnel gap between two conductors using a high resolution transmission electron microscope. A 2.5 mm square micromachined tunneling microscope chip has been fabricated with a minimum feature size of 0.4 μm. The chip fits into a modified side-entry type transmission electron microscope holder. The tunnel gap is controlled by a purpose-built feedback controller. The micromachines work reliably during observation of the tip apex in a transmission electron microscope, allowing the voltage and current to be changed while the tunnel gap is observed.

  1. Materials characterisation by angle-resolved scanning transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Müller-Caspary, Knut; Oppermann, Oliver; Grieb, Tim; Krause, Florian F.; Rosenauer, Andreas; Schowalter, Marco; Mehrtens, Thorsten; Beyer, Andreas; Volz, Kerstin; Potapov, Pavel

    2016-11-01

    Solid-state properties such as strain or chemical composition often leave characteristic fingerprints in the angular dependence of electron scattering. Scanning transmission electron microscopy (STEM) is dedicated to probe scattered intensity with atomic resolution, but it drastically lacks angular resolution. Here we report both a setup to exploit the explicit angular dependence of scattered intensity and applications of angle-resolved STEM to semiconductor nanostructures. Our method is applied to measure nitrogen content and specimen thickness in a GaNxAs1‑x layer independently at atomic resolution by evaluating two dedicated angular intervals. We demonstrate contrast formation due to strain and composition in a Si- based metal-oxide semiconductor field effect transistor (MOSFET) with GexSi1‑x stressors as a function of the angles used for imaging. To shed light on the validity of current theoretical approaches this data is compared with theory, namely the Rutherford approach and contemporary multislice simulations. Inconsistency is found for the Rutherford model in the whole angular range of 16–255 mrad. Contrary, the multislice simulations are applicable for angles larger than 35 mrad whereas a significant mismatch is observed at lower angles. This limitation of established simulations is discussed particularly on the basis of inelastic scattering.

  2. Materials characterisation by angle-resolved scanning transmission electron microscopy

    PubMed Central

    Müller-Caspary, Knut; Oppermann, Oliver; Grieb, Tim; Krause, Florian F.; Rosenauer, Andreas; Schowalter, Marco; Mehrtens, Thorsten; Beyer, Andreas; Volz, Kerstin; Potapov, Pavel

    2016-01-01

    Solid-state properties such as strain or chemical composition often leave characteristic fingerprints in the angular dependence of electron scattering. Scanning transmission electron microscopy (STEM) is dedicated to probe scattered intensity with atomic resolution, but it drastically lacks angular resolution. Here we report both a setup to exploit the explicit angular dependence of scattered intensity and applications of angle-resolved STEM to semiconductor nanostructures. Our method is applied to measure nitrogen content and specimen thickness in a GaNxAs1−x layer independently at atomic resolution by evaluating two dedicated angular intervals. We demonstrate contrast formation due to strain and composition in a Si- based metal-oxide semiconductor field effect transistor (MOSFET) with GexSi1−x stressors as a function of the angles used for imaging. To shed light on the validity of current theoretical approaches this data is compared with theory, namely the Rutherford approach and contemporary multislice simulations. Inconsistency is found for the Rutherford model in the whole angular range of 16–255 mrad. Contrary, the multislice simulations are applicable for angles larger than 35 mrad whereas a significant mismatch is observed at lower angles. This limitation of established simulations is discussed particularly on the basis of inelastic scattering. PMID:27849001

  3. Materials characterisation by angle-resolved scanning transmission electron microscopy.

    PubMed

    Müller-Caspary, Knut; Oppermann, Oliver; Grieb, Tim; Krause, Florian F; Rosenauer, Andreas; Schowalter, Marco; Mehrtens, Thorsten; Beyer, Andreas; Volz, Kerstin; Potapov, Pavel

    2016-11-16

    Solid-state properties such as strain or chemical composition often leave characteristic fingerprints in the angular dependence of electron scattering. Scanning transmission electron microscopy (STEM) is dedicated to probe scattered intensity with atomic resolution, but it drastically lacks angular resolution. Here we report both a setup to exploit the explicit angular dependence of scattered intensity and applications of angle-resolved STEM to semiconductor nanostructures. Our method is applied to measure nitrogen content and specimen thickness in a GaNxAs1-x layer independently at atomic resolution by evaluating two dedicated angular intervals. We demonstrate contrast formation due to strain and composition in a Si- based metal-oxide semiconductor field effect transistor (MOSFET) with GexSi1-x stressors as a function of the angles used for imaging. To shed light on the validity of current theoretical approaches this data is compared with theory, namely the Rutherford approach and contemporary multislice simulations. Inconsistency is found for the Rutherford model in the whole angular range of 16-255 mrad. Contrary, the multislice simulations are applicable for angles larger than 35 mrad whereas a significant mismatch is observed at lower angles. This limitation of established simulations is discussed particularly on the basis of inelastic scattering.

  4. Structural Fingerprinting of Nanocrystals in the Transmission Electron Microscope

    NASA Astrophysics Data System (ADS)

    Rouvimov, Sergei; Plachinda, Pavel; Moeck, Peter

    2010-03-01

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

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

    DTIC Science & Technology

    2005-01-01

    AFRL-ML-WP-TP-2006-464 HIGH-RESOLUTION OF ELECTRON MICROSCOPY OF MONTMORILLONITE AND MONTMORILLONITE /EPOXY NANOCOMPOSITES Lawrence F...HIGH-RESOLUTION OF ELECTRON MICROSCOPY OF MONTMORILLONITE AND MONTMORILLONITE /EPOXY NANOCOMPOSITES 5c. PROGRAM ELEMENT NUMBER 62102F 5d...transmission electron microscopy the structure and morphology of montmorillonite (MMT), a material of current interest for use in polymer nanocomposites, was

  6. Contamination mitigation strategies for scanning transmission electron microscopy.

    PubMed

    Mitchell, D R G

    2015-06-01

    Modern scanning transmission electron microscopy (STEM) enables imaging and microanalysis at very high magnification. In the case of aberration-corrected STEM, atomic resolution is readily achieved. However, the electron fluxes used may be up to three orders of magnitude greater than those typically employed in conventional STEM. Since specimen contamination often increases with electron flux, specimen cleanliness is a critical factor in obtaining meaningful data when carrying out high magnification STEM. A range of different specimen cleaning methods have been applied to a variety of specimen types. The contamination rate has been measured quantitatively to assess the effectiveness of cleaning. The methods studied include: baking, cooling, plasma cleaning, beam showering and UV/ozone exposure. Of the methods tested, beam showering is rapid, experimentally convenient and very effective on a wide range of specimens. Oxidative plasma cleaning is also very effective and can be applied to specimens on carbon support films, albeit with some care. For electron beam-sensitive materials, cooling may be the method of choice. In most cases, preliminary removal of the bulk of the contamination by methods such as baking or plasma cleaning, followed by beam showering, where necessary, can result in a contamination-free specimen suitable for extended atomic scale imaging and analysis.

  7. Ultra-high resolution electron microscopy

    NASA Astrophysics Data System (ADS)

    Oxley, Mark P.; Lupini, Andrew R.; Pennycook, Stephen J.

    2017-02-01

    The last two decades have seen dramatic advances in the resolution of the electron microscope brought about by the successful correction of lens aberrations that previously limited resolution for most of its history. We briefly review these advances, the achievement of sub-Ångstrom resolution and the ability to identify individual atoms, their bonding configurations and even their dynamics and diffusion pathways. We then present a review of the basic physics of electron scattering, lens aberrations and their correction, and an approximate imaging theory for thin crystals which provides physical insight into the various different imaging modes. Then we proceed to describe a more exact imaging theory starting from Yoshioka’s formulation and covering full image simulation methods using Bloch waves, the multislice formulation and the frozen phonon/quantum excitation of phonons models. Delocalization of inelastic scattering has become an important limiting factor at atomic resolution. We therefore discuss this issue extensively, showing how the full-width-half-maximum is the appropriate measure for predicting image contrast, but the diameter containing 50% of the excitation is an important measure of the range of the interaction. These two measures can differ by a factor of 5, are not a simple function of binding energy, and full image simulations are required to match to experiment. The Z-dependence of annular dark field images is also discussed extensively, both for single atoms and for crystals, and we show that temporal incoherence must be included accurately if atomic species are to be identified through matching experimental intensities to simulations. Finally we mention a few promising directions for future investigation.

  8. Ultra-high resolution electron microscopy

    DOE PAGES

    Oxley, Mark P.; Lupini, Andrew R.; Pennycook, Stephen J.

    2016-12-23

    The last two decades have seen dramatic advances in the resolution of the electron microscope brought about by the successful correction of lens aberrations that previously limited resolution for most of its history. Here we briefly review these advances, the achievement of sub-Ångstrom resolution and the ability to identify individual atoms, their bonding configurations and even their dynamics and diffusion pathways. We then present a review of the basic physics of electron scattering, lens aberrations and their correction, and an approximate imaging theory for thin crystals which provides physical insight into the various different imaging modes. Then we proceed tomore » describe a more exact imaging theory starting from Yoshioka’s formulation and covering full image simulation methods using Bloch waves, the multislice formulation and the frozen phonon/quantum excitation of phonons models. Delocalization of inelastic scattering has become an important limiting factor at atomic resolution. We therefore discuss this issue extensively, showing how the full-width-half-maximum is the appropriate measure for predicting image contrast, but the diameter containing 50% of the excitation is an important measure of the range of the interaction. These two measures can differ by a factor of 5, are not a simple function of binding energy, and full image simulations are required to match to experiment. The Z-dependence of annular dark field images is also discussed extensively, both for single atoms and for crystals, and we show that temporal incoherence must be included accurately if atomic species are to be identified through matching experimental intensities to simulations. Finally we mention a few promising directions for future investigation.« less

  9. Ultra-high resolution electron microscopy

    SciTech Connect

    Oxley, Mark P.; Lupini, Andrew R.; Pennycook, Stephen J.

    2016-12-23

    The last two decades have seen dramatic advances in the resolution of the electron microscope brought about by the successful correction of lens aberrations that previously limited resolution for most of its history. Here we briefly review these advances, the achievement of sub-Ångstrom resolution and the ability to identify individual atoms, their bonding configurations and even their dynamics and diffusion pathways. We then present a review of the basic physics of electron scattering, lens aberrations and their correction, and an approximate imaging theory for thin crystals which provides physical insight into the various different imaging modes. Then we proceed to describe a more exact imaging theory starting from Yoshioka’s formulation and covering full image simulation methods using Bloch waves, the multislice formulation and the frozen phonon/quantum excitation of phonons models. Delocalization of inelastic scattering has become an important limiting factor at atomic resolution. We therefore discuss this issue extensively, showing how the full-width-half-maximum is the appropriate measure for predicting image contrast, but the diameter containing 50% of the excitation is an important measure of the range of the interaction. These two measures can differ by a factor of 5, are not a simple function of binding energy, and full image simulations are required to match to experiment. The Z-dependence of annular dark field images is also discussed extensively, both for single atoms and for crystals, and we show that temporal incoherence must be included accurately if atomic species are to be identified through matching experimental intensities to simulations. Finally we mention a few promising directions for future investigation.

  10. Nanomaterial datasets to advance tomography in scanning transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Levin, Barnaby D. A.; Padgett, Elliot; Chen, Chien-Chun; Scott, M. C.; Xu, Rui; Theis, Wolfgang; Jiang, Yi; Yang, Yongsoo; Ophus, Colin; Zhang, Haitao; Ha, Don-Hyung; Wang, Deli; Yu, Yingchao; Abruña, Hector D.; Robinson, Richard D.; Ercius, Peter; Kourkoutis, Lena F.; Miao, Jianwei; Muller, David A.; Hovden, Robert

    2016-06-01

    Electron tomography in materials science has flourished with the demand to characterize nanoscale materials in three dimensions (3D). Access to experimental data is vital for developing and validating reconstruction methods that improve resolution and reduce radiation dose requirements. This work presents five high-quality scanning transmission electron microscope (STEM) tomography datasets in order to address the critical need for open access data in this field. The datasets represent the current limits of experimental technique, are of high quality, and contain materials with structural complexity. Included are tomographic series of a hyperbranched Co2P nanocrystal, platinum nanoparticles on a carbon nanofibre imaged over the complete 180° tilt range, a platinum nanoparticle and a tungsten needle both imaged at atomic resolution by equal slope tomography, and a through-focal tilt series of PtCu nanoparticles. A volumetric reconstruction from every dataset is provided for comparison and development of post-processing and visualization techniques. Researchers interested in creating novel data processing and reconstruction algorithms will now have access to state of the art experimental test data.

  11. Nanomaterial datasets to advance tomography in scanning transmission electron microscopy

    PubMed Central

    Levin, Barnaby D.A.; Padgett, Elliot; Chen, Chien-Chun; Scott, M.C.; Xu, Rui; Theis, Wolfgang; Jiang, Yi; Yang, Yongsoo; Ophus, Colin; Zhang, Haitao; Ha, Don-Hyung; Wang, Deli; Yu, Yingchao; Abruña, Hector D.; Robinson, Richard D.; Ercius, Peter; Kourkoutis, Lena F.; Miao, Jianwei; Muller, David A.; Hovden, Robert

    2016-01-01

    Electron tomography in materials science has flourished with the demand to characterize nanoscale materials in three dimensions (3D). Access to experimental data is vital for developing and validating reconstruction methods that improve resolution and reduce radiation dose requirements. This work presents five high-quality scanning transmission electron microscope (STEM) tomography datasets in order to address the critical need for open access data in this field. The datasets represent the current limits of experimental technique, are of high quality, and contain materials with structural complexity. Included are tomographic series of a hyperbranched Co2P nanocrystal, platinum nanoparticles on a carbon nanofibre imaged over the complete 180° tilt range, a platinum nanoparticle and a tungsten needle both imaged at atomic resolution by equal slope tomography, and a through-focal tilt series of PtCu nanoparticles. A volumetric reconstruction from every dataset is provided for comparison and development of post-processing and visualization techniques. Researchers interested in creating novel data processing and reconstruction algorithms will now have access to state of the art experimental test data. PMID:27272459

  12. Nanomaterial datasets to advance tomography in scanning transmission electron microscopy.

    PubMed

    Levin, Barnaby D A; Padgett, Elliot; Chen, Chien-Chun; Scott, M C; Xu, Rui; Theis, Wolfgang; Jiang, Yi; Yang, Yongsoo; Ophus, Colin; Zhang, Haitao; Ha, Don-Hyung; Wang, Deli; Yu, Yingchao; Abruña, Hector D; Robinson, Richard D; Ercius, Peter; Kourkoutis, Lena F; Miao, Jianwei; Muller, David A; Hovden, Robert

    2016-06-07

    Electron tomography in materials science has flourished with the demand to characterize nanoscale materials in three dimensions (3D). Access to experimental data is vital for developing and validating reconstruction methods that improve resolution and reduce radiation dose requirements. This work presents five high-quality scanning transmission electron microscope (STEM) tomography datasets in order to address the critical need for open access data in this field. The datasets represent the current limits of experimental technique, are of high quality, and contain materials with structural complexity. Included are tomographic series of a hyperbranched Co2P nanocrystal, platinum nanoparticles on a carbon nanofibre imaged over the complete 180° tilt range, a platinum nanoparticle and a tungsten needle both imaged at atomic resolution by equal slope tomography, and a through-focal tilt series of PtCu nanoparticles. A volumetric reconstruction from every dataset is provided for comparison and development of post-processing and visualization techniques. Researchers interested in creating novel data processing and reconstruction algorithms will now have access to state of the art experimental test data.

  13. 8 CFR 217.7 - Electronic data transmission requirement.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 8 Aliens and Nationality 1 2012-01-01 2012-01-01 false Electronic data transmission requirement. 217.7 Section 217.7 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS VISA WAIVER PROGRAM § 217.7 Electronic data transmission requirement. (a) An alien who applies...

  14. 8 CFR 217.7 - Electronic data transmission requirement.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 8 Aliens and Nationality 1 2013-01-01 2013-01-01 false Electronic data transmission requirement. 217.7 Section 217.7 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS VISA WAIVER PROGRAM § 217.7 Electronic data transmission requirement. (a) An alien who applies...

  15. 8 CFR 217.7 - Electronic data transmission requirement.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Electronic data transmission requirement. 217.7 Section 217.7 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS VISA WAIVER PROGRAM § 217.7 Electronic data transmission requirement. (a) An alien who applies...

  16. 8 CFR 217.7 - Electronic data transmission requirement.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 8 Aliens and Nationality 1 2011-01-01 2011-01-01 false Electronic data transmission requirement. 217.7 Section 217.7 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS VISA WAIVER PROGRAM § 217.7 Electronic data transmission requirement. (a) An alien who applies...

  17. 8 CFR 217.7 - Electronic data transmission requirement.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 8 Aliens and Nationality 1 2014-01-01 2014-01-01 false Electronic data transmission requirement. 217.7 Section 217.7 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS VISA WAIVER PROGRAM § 217.7 Electronic data transmission requirement. (a) An alien who applies...

  18. Dynamical behaviour of nanocrystals in transmission electron microscopy: size, temperature or irradiation effects.

    PubMed

    Buffat, Philippe André

    2003-02-15

    High-resolution transmission electron microscopy shows that metal nanoparticles sinter within a fraction of a second under an electron beam at 'room temperature' as long as classical models of thermal equilibrium apply. Images exhibit crystal planes that change in orientation with time as if the particle was undergoing melting and resolidification processes. We explore whether these dynamical effects are the result of heating or transformation effects in the electron microscope or quantum fluctuations in small systems.

  19. Mapping magnetism with atomic resolution using aberrated electron probes

    NASA Astrophysics Data System (ADS)

    Idrobo, Juan; Rusz, Ján; McGuire, Michael A.; Symons, Christopher T.; Vatsavai, Ranga Raju; Lupini, Andrew R.

    2015-03-01

    In this talk, we report a direct experimental real-space mapping of magnetic circular dichroism with atomic resolution in aberration-corrected scanning transmission electron microscopy (STEM). Using an aberrated electron probe with customized phase distribution, we reveal with electron energy-loss (EEL) spectroscopy the checkerboard antiferromagnetic ordering of Mn moments in LaMnAsO by observing a dichroic signal in the Mn L-edge. The aberrated probes allow the collection of EEL spectra using the transmitted beam, which results in a magnetic circular dichroic signal with intrinsically larger signal-to-noise ratios than those obtained via nanodiffraction techniques (where most of the transmitted electrons are discarded). The novel experimental setup presented here, which can easily be implemented in aberration-corrected STEM, opens new paths for probing dichroic signals in materials with unprecedented spatial resolution. This research was supported by DOE SUFD MSED, by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the US DOE, and by the Swedish Research Council and Swedish National Infrastructure for Computing (NSC center)

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

    PubMed

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

    2012-07-27

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

  1. Aberrated electron probes for magnetic spectroscopy with atomic resolution: Theory and practical aspects

    SciTech Connect

    Rusz, Ján; Idrobo, Juan Carlos

    2016-03-24

    It was recently proposed that electron magnetic circular dichroism (EMCD) can be measured in scanning transmission electron microscopy (STEM) with atomic resolution by tuning the phase distribution of a electron beam. Here, we describe the theoretical and practical aspects for the detection of out-of-plane and in-plane magnetization utilizing atomic size electron probes. Here we present the calculated optimized astigmatic probes and discuss how to achieve them experimentally.

  2. Transmission Kikuchi diffraction and transmission electron forescatter imaging of electropolished and FIB manufactured TEM specimens

    SciTech Connect

    Zieliński, W. Płociński, T.; Kurzydłowski, K.J.

    2015-06-15

    We present a study of the efficiency of the utility of scanning electron microscope (SEM)-based transmission methods for characterizing grain structure in thinned bulk metals. Foils of type 316 stainless steel were prepared by two methods commonly used for transmission electron microscopy — double-jet electropolishing and focused ion beam milling. A customized holder allowed positioning of the foils in a configuration appropriate for both transmission electron forward scatter diffraction, and for transmission imaging by the use of a forescatter detector with two diodes. We found that both crystallographic orientation maps and dark-field transmitted images could be obtained for specimens prepared by either method. However, for both methods, preparation-induced artifacts may affect the quality or accuracy of transmission SEM data, especially those acquired by the use of transmission Kikuchi diffraction. Generally, the quality of orientation data was better for specimens prepared by electropolishing, due to the absence of ion-induced damage. - Highlights: • The transmission imaging and diffraction techniques are emerging in scanning electron microscopy (SEM) as promising new field of materials characterization. • The manuscript titled: “Transmission Kikuchi Diffraction and Transmission Electron Forescatter Imaging of Electropolished and FIB Manufactured TEM Specimens” documents how different specimen thinning procedures can effect efficiency of transmission Kikuchi diffraction and transmission electron forescatter imaging. • The abilities to make precision crystallographic orientation maps and dark-field images in transmission was studied on electropolished versus focus ion beam manufactured TEM specimens. • Depending on the need, electropolished and focused ion beam technique may produce suitable specimens for transmission imaging and diffraction in SEM.

  3. Depth Sectioning with the Aberration-Corrected Scanning Transmission Electron Microscope

    SciTech Connect

    Borisevich, Albina Y; Lupini, Andrew R; Pennycook, Stephen J

    2006-01-01

    The ability to correct the aberrations of the probe-forming lens in the scanning transmission electron microscope provides not only a significant improvement in transverse resolution but in addition brings depth resolution at the nanometer scale. Aberration correction therefore opens up the possibility of 3D imaging by optical sectioning. Here we develop a definition for the depth resolution for scanning transmission electron microscope depth sectioning and present initial results from this method. Objects such as catalytic metal clusters and single atoms on various support materials are imaged in three dimensions with a resolution of several nanometers. Effective focal depth is determined by statistical analysis and the contributing factors are discussed. Finally, current challenges and future capabilities available through new instruments are discussed.

  4. Time of flight secondary ion mass spectrometry and high-resolution transmission electron microscopy/energy dispersive spectroscopy: a preliminary study of the distribution of Cu2+ and Cu2+/Pb2+ on a Bt horizon surfaces.

    PubMed

    Cerqueira, B; Vega, F A; Serra, C; Silva, L F O; Andrade, M L

    2011-11-15

    Relatively new techniques can help in determining the occurrence of mineral species and the distribution of contaminants on soil surfaces such as natural minerals and organic matter. The Bt horizon from an Endoleptic Luvisol was chosen because of its well-known sorption capability. The samples were contaminated with Cu(2+) and/or Pb(2+) and both sorption and desorption experiments were performed. The preferential distribution of the contaminant species ((63)Cu and (208)Pb) to the main soil components and their associations were studied together with the effectiveness of the surface sorption and desorption processes. The results obtained were compared with non-contaminated samples as well as with previous results obtained by different analytical techniques and advanced statistical analysis. Pb(2+) competes favorably for the sorption sites in this soil, mainly in oxides and the clay fraction. Cu(2+) and Pb(2+) were mainly associated with hematite, gibbsite, vermiculite and chlorite. This study will serve as a basis for further scientific research on the soil retention of heavy metals. New techniques such as spectroscopic imaging and transmission electron microscopy make it possible to check which soil components retain heavy metals, thereby contributing to propose effective measures for the remediation of contaminated soil.

  5. High Cycle Fatigue in the Transmission Electron Microscope.

    PubMed

    Bufford, Daniel C; Stauffer, Douglas; Mook, William M; Syed Asif, S A; Boyce, Brad L; Hattar, Khalid

    2016-08-10

    One of the most common causes of structural failure in metals is fatigue induced by cyclic loading. Historically, microstructure-level analysis of fatigue cracks has primarily been performed post mortem. However, such investigations do not directly reveal the internal structural processes at work near micro- and nanoscale fatigue cracks and thus do not provide direct evidence of active microstructural mechanisms. In this study, the tension-tension fatigue behavior of nanocrystalline Cu was monitored in real time at the nanoscale by utilizing a new capability for quantitative cyclic mechanical loading performed in situ in a transmission electron microscope (TEM). Controllable loads were applied at frequencies from one to several hundred hertz, enabling accumulations of 10(6) cycles within 1 h. The nanometer-scale spatial resolution of the TEM allows quantitative fatigue crack growth studies at very slow crack growth rates, measured here at ∼10(-12) m·cycle(-1). This represents an incipient threshold regime that is well below the tensile yield stress and near the minimum conditions for fatigue crack growth. Evidence of localized deformation and grain growth within 150 nm of the crack tip was observed by both standard imaging and precession electron diffraction orientation mapping. These observations begin to reveal with unprecedented detail the local microstructural processes that govern damage accumulation, crack nucleation, and crack propagation during fatigue loading in nanocrystalline Cu.

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

    SciTech Connect

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

    2011-01-01

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

  7. Combined scanning transmission electron microscopy tilt- and focal series.

    PubMed

    Dahmen, Tim; Baudoin, Jean-Pierre; Lupini, Andrew R; Kübel, Christian; Slusallek, Philipp; de Jonge, Niels

    2014-04-01

    In this study, a combined tilt- and focal series is proposed as a new recording scheme for high-angle annular dark-field scanning transmission electron microscopy (STEM) tomography. Three-dimensional (3D) data were acquired by mechanically tilting the specimen, and recording a through-focal series at each tilt direction. The sample was a whole-mount macrophage cell with embedded gold nanoparticles. The tilt-focal algebraic reconstruction technique (TF-ART) is introduced as a new algorithm to reconstruct tomograms from such combined tilt- and focal series. The feasibility of TF-ART was demonstrated by 3D reconstruction of the experimental 3D data. The results were compared with a conventional STEM tilt series of a similar sample. The combined tilt- and focal series led to smaller "missing wedge" artifacts, and a higher axial resolution than obtained for the STEM tilt series, thus improving on one of the main issues of tilt series-based electron tomography.

  8. Transmission electron microscope calibration methods for critical dimension standards

    NASA Astrophysics Data System (ADS)

    Orji, Ndubuisi G.; Dixson, Ronald G.; Garcia-Gutierrez, Domingo I.; Bunday, Benjamin D.; Bishop, Michael; Cresswell, Michael W.; Allen, Richard A.; Allgair, John A.

    2016-10-01

    One of the key challenges in critical dimension (CD) metrology is finding suitable dimensional calibration standards. The transmission electron microscope (TEM), which produces lattice-resolved images having scale traceability to the SI (International System of Units) definition of length through an atomic lattice constant, has gained wide usage in different areas of CD calibration. One such area is critical dimension atomic force microscope (CD-AFM) tip width calibration. To properly calibrate CD-AFM tip widths, errors in the calibration process must be quantified. Although the use of TEM for CD-AFM tip width calibration has been around for about a decade, there is still confusion on what should be considered in the uncertainty analysis. We characterized CD-AFM tip-width samples using high-resolution TEM and high angle annular dark field scanning TEM and two CD-AFMs that are implemented as reference measurement systems. The results are used to outline how to develop a rigorous uncertainty estimate for TEM/CD-AFM calibration, and to compare how information from the two electron microscopy modes are applied to practical CD-AFM measurements. The results also represent a separate validation of previous TEM/CD-AFM calibration. Excellent agreement was observed.

  9. Amyloid structure and assembly: insights from scanning transmission electron microscopy.

    PubMed

    Goldsbury, Claire; Baxa, Ulrich; Simon, Martha N; Steven, Alasdair C; Engel, Andreas; Wall, Joseph S; Aebi, Ueli; Müller, Shirley A

    2011-01-01

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

  10. High cycle fatigue in the transmission electron microscope

    DOE PAGES

    Bufford, Daniel C.; Stauffer, Douglas; Mook, William M.; ...

    2016-06-28

    One of the most common causes of structural failure in metals is fatigue induced by cyclic loading. Historically, microstructure-level analysis of fatigue cracks has primarily been performed post mortem. However, such investigations do not directly reveal the internal structural processes at work near micro- and nanoscale fatigue cracks and thus do not provide direct evidence of active microstructural mechanisms. In this paper, the tension–tension fatigue behavior of nanocrystalline Cu was monitored in real time at the nanoscale by utilizing a new capability for quantitative cyclic mechanical loading performed in situ in a transmission electron microscope (TEM). Controllable loads were appliedmore » at frequencies from one to several hundred hertz, enabling accumulations of 106 cycles within 1 h. The nanometer-scale spatial resolution of the TEM allows quantitative fatigue crack growth studies at very slow crack growth rates, measured here at ~10–12 m·cycle–1. This represents an incipient threshold regime that is well below the tensile yield stress and near the minimum conditions for fatigue crack growth. Evidence of localized deformation and grain growth within 150 nm of the crack tip was observed by both standard imaging and precession electron diffraction orientation mapping. Finally, these observations begin to reveal with unprecedented detail the local microstructural processes that govern damage accumulation, crack nucleation, and crack propagation during fatigue loading in nanocrystalline Cu.« less

  11. High cycle fatigue in the transmission electron microscope

    SciTech Connect

    Bufford, Daniel C.; Stauffer, Douglas; Mook, William M.; Syed Asif, S. A.; Boyce, Brad L.; Hattar, Khalid

    2016-06-28

    One of the most common causes of structural failure in metals is fatigue induced by cyclic loading. Historically, microstructure-level analysis of fatigue cracks has primarily been performed post mortem. However, such investigations do not directly reveal the internal structural processes at work near micro- and nanoscale fatigue cracks and thus do not provide direct evidence of active microstructural mechanisms. In this paper, the tension–tension fatigue behavior of nanocrystalline Cu was monitored in real time at the nanoscale by utilizing a new capability for quantitative cyclic mechanical loading performed in situ in a transmission electron microscope (TEM). Controllable loads were applied at frequencies from one to several hundred hertz, enabling accumulations of 106 cycles within 1 h. The nanometer-scale spatial resolution of the TEM allows quantitative fatigue crack growth studies at very slow crack growth rates, measured here at ~10–12 m·cycle–1. This represents an incipient threshold regime that is well below the tensile yield stress and near the minimum conditions for fatigue crack growth. Evidence of localized deformation and grain growth within 150 nm of the crack tip was observed by both standard imaging and precession electron diffraction orientation mapping. Finally, these observations begin to reveal with unprecedented detail the local microstructural processes that govern damage accumulation, crack nucleation, and crack propagation during fatigue loading in nanocrystalline Cu.

  12. Phase reconstruction in annular bright-field scanning transmission electron microscopy.

    PubMed

    Ishida, Takafumi; Kawasaki, Tadahiro; Tanji, Takayoshi; Kodama, Tetsuji; Matsutani, Takaomi; Ogai, Keiko; Ikuta, Takashi

    2015-04-01

    A novel technique for reconstructing the phase shifts of electron waves was applied to Cs-corrected scanning transmission electron microscopy (STEM). To realize this method, a new STEM system equipped with an annular aperture, annularly arrayed detectors and an arrayed image processor has been developed and evaluated in experiments. We show a reconstructed phase image of graphite particles and demonstrate that this new method works effectively for high-resolution phase imaging.

  13. Standardless atom counting in scanning transmission electron microscopy.

    PubMed

    LeBeau, James M; Findlay, Scott D; Allen, Leslie J; Stemmer, Susanne

    2010-11-10

    We demonstrate that high-angle annular dark-field imaging in scanning transmission electron microscopy allows for quantification of the number and location of all atoms in a three-dimensional, crystalline, arbitrarily shaped specimen without the need for a calibration standard. We show that the method also provides for an approach to directly measure the finite effective source size of a scanning transmission electron microscope.

  14. Fluorescence-integrated transmission electron microscopy images: integrating fluorescence microscopy with transmission electron microscopy.

    PubMed

    Sims, Paul A; Hardin, Jeff D

    2007-01-01

    This chapter describes high-pressure freezing (HPF) techniques for correlative light and electron microscopy on the same sample. Laser scanning confocal microscopy (LSCM) is exploited for its ability to collect fluorescent, as well as transmitted and back scattered light (BSL) images at the same time. Fluorescent information from a whole mount (preembedding) or from thin sections (post-embedding) can be displayed as a color overlay on transmission electron microscopy (TEM) images. Fluorescence-integrated TEM (F-TEM) images provide a fluorescent perspective to TEM images. The pre-embedding method uses a thin two-part agarose pad to immobilize live Caenorhabditis elegans embryos for LSCM, HPF, and TEM. Pre-embedding F-TEM images display fluorescent information collected from a whole mount of live embryos onto all thin sections collected from that sample. In contrast, the postembedding method uses HPF and freeze substitution with 1% paraformaldehyde in 95% ethanol followed by low-temperature embedding in methacrylate resin. This procedure preserves the structure and function of green fluorescent protein (GFP) as determined by immunogold labeling of GFP, when compared with GFP expression, both demonstrated in the same thin section.

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

    PubMed

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

    2011-06-01

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

  16. Visualizing Macromolecular Complexes with In Situ Liquid Scanning Transmission Electron Microscopy

    SciTech Connect

    Evans, James E.; Jungjohann, K. L.; Wong, Peony C. K.; Chiu, Po-Lin; Dutrow, Gavin H.; Arslan, Ilke; Browning, Nigel D.

    2012-11-01

    A central focus of biological research is understanding the structure/function relationship of macromolecular protein complexes. Yet conventional transmission electron microscopy techniques are limited to static observations. Here we present the first direct images of purified macromolecular protein complexes using in situ liquid scanning transmission electron microscopy. Our results establish the capability of this technique for visualizing the interface between biology and nanotechnology with high fidelity while also probing the interactions of biomolecules within solution. This method represents an important advancement towards allowing future high-resolution observations of biological processes and conformational dynamics in real-time.

  17. Visualizing macromolecular complexes with in situ liquid scanning transmission electron microscopy.

    PubMed

    Evans, James E; Jungjohann, Katherine L; Wong, Peony C K; Chiu, Po-Lin; Dutrow, Gavin H; Arslan, Ilke; Browning, Nigel D

    2012-11-01

    A central focus of biological research is understanding the structure/function relationship of macromolecular protein complexes. Yet conventional transmission electron microscopy techniques are limited to static observations. Here we present the first direct images of purified macromolecular protein complexes using in situ liquid scanning transmission electron microscopy. Our results establish the capability of this technique for visualizing the interface between biology and nanotechnology with high fidelity while also probing the interactions of biomolecules within solution. This method represents an important advancement towards allowing future high-resolution observations of biological processes and conformational dynamics in real-time.

  18. Electron transmission through a class of anthracene aldehyde molecules

    NASA Astrophysics Data System (ADS)

    Petreska, Irina; Ohanesjan, Vladimir; Pejov, Ljupco; Kocarev, Ljupco

    2016-03-01

    Transmission of electrons via metal-molecule-metal junctions, involving rotor-stator anthracene aldehyde molecules is investigated. Two model barriers having input parameters evaluated from accurate ab initio calculations are proposed and the transmission coefficients are obtained by using the quasiclassical approximation. Transmission coefficients further enter in the integral for the net current, utilizing Simmons' method. Conformational dependence of the tunneling processes is evident and the presence of the side groups enhances the functionality of the future single-molecule based electronic devices.

  19. Transmission electron microscopy and electrical transport investigations performed on the same single-walled carbon nanotube

    SciTech Connect

    Philipp, G.; Burghard, M.; Roth, S.

    1998-08-11

    Electrical transport measurements and high resolution transmission electron microscopy performed on the same (rope of) single-walled carbon nanotube(s) (SWCNTs) allow to establish links between structural and electronic properties of the tubes. The tubes are deposited on electron transparent ultrathin Si{sub 3}N{sub 4}-membranes bearing Cr/AuPd-electrodes defined by electron beam lithography. TEM-micrographs of the setup reveal mostly ropes consisting of 2-3 tubes which also appear on a scanning force microscope image of the same area. A current-voltage trace of the ropes at 4.2 K is also presented.

  20. Possibilities and limitations of advanced transmission electron microscopy for carbon-based nanomaterials.

    PubMed

    Ke, Xiaoxing; Bittencourt, Carla; Van Tendeloo, Gustaaf

    2015-01-01

    A major revolution for electron microscopy in the past decade is the introduction of aberration correction, which enables one to increase both the spatial resolution and the energy resolution to the optical limit. Aberration correction has contributed significantly to the imaging at low operating voltages. This is crucial for carbon-based nanomaterials which are sensitive to electron irradiation. The research of carbon nanomaterials and nanohybrids, in particular the fundamental understanding of defects and interfaces, can now be carried out in unprecedented detail by aberration-corrected transmission electron microscopy (AC-TEM). This review discusses new possibilities and limits of AC-TEM at low voltage, including the structural imaging at atomic resolution, in three dimensions and spectroscopic investigation of chemistry and bonding. In situ TEM of carbon-based nanomaterials is discussed and illustrated through recent reports with particular emphasis on the underlying physics of interactions between electrons and carbon atoms.

  1. Possibilities and limitations of advanced transmission electron microscopy for carbon-based nanomaterials

    PubMed Central

    Bittencourt, Carla; Van Tendeloo, Gustaaf

    2015-01-01

    Summary A major revolution for electron microscopy in the past decade is the introduction of aberration correction, which enables one to increase both the spatial resolution and the energy resolution to the optical limit. Aberration correction has contributed significantly to the imaging at low operating voltages. This is crucial for carbon-based nanomaterials which are sensitive to electron irradiation. The research of carbon nanomaterials and nanohybrids, in particular the fundamental understanding of defects and interfaces, can now be carried out in unprecedented detail by aberration-corrected transmission electron microscopy (AC-TEM). This review discusses new possibilities and limits of AC-TEM at low voltage, including the structural imaging at atomic resolution, in three dimensions and spectroscopic investigation of chemistry and bonding. In situ TEM of carbon-based nanomaterials is discussed and illustrated through recent reports with particular emphasis on the underlying physics of interactions between electrons and carbon atoms. PMID:26425406

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

    PubMed

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

    2012-10-01

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

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

    PubMed

    Kubo, Yugo; Hamada, Kotaro; Urano, Akira

    2013-12-01

    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.

  4. High-Resolution Analytical Electron Microscopy Characterization of Corrosion and Cracking at Buried Interfaces

    SciTech Connect

    Bruemmer, Stephen M.; Thomas, Larry E.

    2001-07-01

    Recent results are presented demonstrating the application of cross-sectional analytical transmission electron microscopy (ATEM) to corrosion and cracking in high-temperature water environments. Microstructural, chemical and crystallographic characterization of buried interfaces at near-atomic resolutions is shown to reveal evidence for unexpected local environments, corrosion reactions and material transformations. Information obtained by a wide variety of high-resolution imaging and analysis methods indicates the processes occurring during crack advance and provides insights into the mechanisms controlling environmental degradation.

  5. The spatial coherence function in scanning transmission electron microscopy and spectroscopy.

    PubMed

    Nguyen, D T; Findlay, S D; Etheridge, J

    2014-11-01

    We investigate the implications of the form of the spatial coherence function, also referred to as the effective source distribution, for quantitative analysis in scanning transmission electron microscopy, and in particular for interpreting the spatial origin of imaging and spectroscopy signals. These questions are explored using three different source distribution models applied to a GaAs crystal case study. The shape of the effective source distribution was found to have a strong influence not only on the scanning transmission electron microscopy (STEM) image contrast, but also on the distribution of the scattered electron wavefield and hence on the spatial origin of the detected electron intensities. The implications this has for measuring structure, composition and bonding at atomic resolution via annular dark field, X-ray and electron energy loss STEM imaging are discussed.

  6. Dose-dependent high-resolution electron ptychography

    SciTech Connect

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

    2016-02-07

    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.

  7. First experimental proof for aberration correction in XPEEM: resolution, transmission enhancement, and limitation by space charge effects.

    PubMed

    Schmidt, Th; Sala, A; Marchetto, H; Umbach, E; Freund, H-J

    2013-03-01

    The positive effect of double aberration correction in x-ray induced Photoelectron Emission Microscopy (XPEEM) has been successfully demonstrated for both, the lateral resolution and the transmission, using the Au 4f XPS peak for element specific imaging at a kinetic energy of 113 eV. The lateral resolution is improved by a factor of four, compared to a non-corrected system, whereas the transmission is enhanced by a factor of 5 at a moderate resolution of 80 nm. With an optimized system setting, a lateral resolution of 18 nm could be achieved, which is up to now the best value reported for energy filtered XPEEM imaging. However, the absolute resolution does not yet reach the theoretical limit of 2 nm, which is due to space charge limitation. This occurs along the entire optical axis up to the contrast aperture. In XPEEM the pulsed time structure of the exciting soft x-ray light source causes a short and highly intense electron pulse, which results in an image blurring. In contrast, the imaging with elastically reflected electrons in the low energy electron microscopy (LEEM) mode yields a resolution clearly below 5 nm. Technical solutions to reduce the space charge effect in an aberration-corrected spectro-microscope are discussed.

  8. Scanning transmission electron microscopy methods for the analysis of nanoparticles.

    PubMed

    Ponce, Arturo; Mejía-Rosales, Sergio; José-Yacamán, Miguel

    2012-01-01

    Here we review the scanning transmission electron microscopy (STEM) characterization technique and STEM imaging methods. We describe applications of STEM for studying inorganic nanoparticles, and other uses of STEM in biological and health sciences and discuss how to interpret STEM results. The STEM imaging mode has certain benefits compared with the broad-beam illumination mode; the main advantage is the collection of the information about the specimen using a high angular annular dark field (HAADF) detector, in which the images registered have different levels of contrast related to the chemical composition of the sample. Another advantage of its use in the analysis of biological samples is its contrast for thick stained sections, since HAADF images of samples with thickness of 100-120 nm have notoriously better contrast than those obtained by other techniques. Combining the HAADF-STEM imaging with the new aberration correction era, the STEM technique reaches a direct way to imaging the atomistic structure and composition of nanostructures at a sub-angstrom resolution. Thus, alloying in metallic nanoparticles is directly resolved at atomic scale by the HAADF-STEM imaging, and the comparison of the STEM images with results from simulations gives a very powerful way of analysis of structure and composition. The use of X-ray energy dispersive spectroscopy attached to the electron microscope for STEM mode is also described. In issues where characterization at the atomic scale of the interaction between metallic nanoparticles and biological systems is needed, all the associated techniques to STEM become powerful tools for the best understanding on how to use these particles in biomedical applications.

  9. Power electronics in electric utilities: HVDC power transmission systems

    SciTech Connect

    Nozari, F.; Patel, H.S.

    1988-04-01

    High Voltage Direct Current (HVDC) power transmission systems constitute an important application of power electronics technology. This paper reviews salient aspects of this growing industry. The paper summarizes the history of HVDC transmission and discusses the economic and technical reasons responsible for development of HVDC systems. The paper also describes terminal design and basic configurations of HVDC systems, as well as major equipments of HVDC transmission system. In this regard, the state-of-the-art technology in the equipments constructions are discussed. Finally, the paper reviews future developments in the HVDC transmission systems, including promising technologies, such as multiterminal configurations, Gate Turn-Off (GTO) devices, forced commutation converters, and new advances in control electronics.

  10. Analysis on electronic control unit of continuously variable transmission

    NASA Astrophysics Data System (ADS)

    Cao, Shuanggui

    Continuously variable transmission system can ensure that the engine work along the line of best fuel economy, improve fuel economy, save fuel and reduce harmful gas emissions. At the same time, continuously variable transmission allows the vehicle speed is more smooth and improves the ride comfort. Although the CVT technology has made great development, but there are many shortcomings in the CVT. The CVT system of ordinary vehicles now is still low efficiency, poor starting performance, low transmission power, and is not ideal controlling, high cost and other issues. Therefore, many scholars began to study some new type of continuously variable transmission. The transmission system with electronic systems control can achieve automatic control of power transmission, give full play to the characteristics of the engine to achieve optimal control of powertrain, so the vehicle is always traveling around the best condition. Electronic control unit is composed of the core processor, input and output circuit module and other auxiliary circuit module. Input module collects and process many signals sent by sensor and , such as throttle angle, brake signals, engine speed signal, speed signal of input and output shaft of transmission, manual shift signals, mode selection signals, gear position signal and the speed ratio signal, so as to provide its corresponding processing for the controller core.

  11. Efficient linear phase contrast in scanning transmission electron microscopy with matched illumination and detector interferometry

    NASA Astrophysics Data System (ADS)

    Ophus, Colin; Ciston, Jim; Pierce, Jordan; Harvey, Tyler R.; Chess, Jordan; McMorran, Benjamin J.; Czarnik, Cory; Rose, Harald H.; Ercius, Peter

    2016-02-01

    The ability to image light elements in soft matter at atomic resolution enables unprecedented insight into the structure and properties of molecular heterostructures and beam-sensitive nanomaterials. In this study, we introduce a scanning transmission electron microscopy technique combining a pre-specimen phase plate designed to produce a probe with structured phase with a high-speed direct electron detector to generate nearly linear contrast images with high efficiency. We demonstrate this method by using both experiment and simulation to simultaneously image the atomic-scale structure of weakly scattering amorphous carbon and strongly scattering gold nanoparticles. Our method demonstrates strong contrast for both materials, making it a promising candidate for structural determination of heterogeneous soft/hard matter samples even at low electron doses comparable to traditional phase-contrast transmission electron microscopy. Simulated images demonstrate the extension of this technique to the challenging problem of structural determination of biological material at the surface of inorganic crystals.

  12. Efficient linear phase contrast in scanning transmission electron microscopy with matched illumination and detector interferometry

    SciTech Connect

    Ophus, Colin; Ciston, Jim; Pierce, Jordan; Harvey, Tyler R.; Chess, Jordan; McMorran, Benjamin J.; Czarnik, Cory; Rose, Harald H.; Ercius, Peter

    2016-02-29

    The ability to image light elements in soft matter at atomic resolution enables unprecedented insight into the structure and properties of molecular heterostructures and beam-sensitive nanomaterials. In this study, we introduce a scanning transmission electron microscopy technique combining a pre-specimen phase plate designed to produce a probe with structured phase with a high-speed direct electron detector to generate nearly linear contrast images with high efficiency. We demonstrate this method by using both experiment and simulation to simultaneously image the atomic-scale structure of weakly scattering amorphous carbon and strongly scattering gold nanoparticles. Our method demonstrates strong contrast for both materials, making it a promising candidate for structural determination of heterogeneous soft/hard matter samples even at low electron doses comparable to traditional phase-contrast transmission electron microscopy. Ultimately, simulated images demonstrate the extension of this technique to the challenging problem of structural determination of biological material at the surface of inorganic crystals.

  13. Efficient linear phase contrast in scanning transmission electron microscopy with matched illumination and detector interferometry.

    PubMed

    Ophus, Colin; Ciston, Jim; Pierce, Jordan; Harvey, Tyler R; Chess, Jordan; McMorran, Benjamin J; Czarnik, Cory; Rose, Harald H; Ercius, Peter

    2016-02-29

    The ability to image light elements in soft matter at atomic resolution enables unprecedented insight into the structure and properties of molecular heterostructures and beam-sensitive nanomaterials. In this study, we introduce a scanning transmission electron microscopy technique combining a pre-specimen phase plate designed to produce a probe with structured phase with a high-speed direct electron detector to generate nearly linear contrast images with high efficiency. We demonstrate this method by using both experiment and simulation to simultaneously image the atomic-scale structure of weakly scattering amorphous carbon and strongly scattering gold nanoparticles. Our method demonstrates strong contrast for both materials, making it a promising candidate for structural determination of heterogeneous soft/hard matter samples even at low electron doses comparable to traditional phase-contrast transmission electron microscopy. Simulated images demonstrate the extension of this technique to the challenging problem of structural determination of biological material at the surface of inorganic crystals.

  14. Electron Diffraction and High-Resolution Electron Microscopy of Mineral Structures

    NASA Astrophysics Data System (ADS)

    Nord, Gordon L., Jr.

    This book is a well-written English translation of the original 1981 Russian edition, Strukturnoye issledovaniye mineralov metodami mikrodifraktsii i elechtronnoi mikroskopii vysokogo razresheniya. The 1987 English version has been extensively updated and includes references up to 1986. The book is essentially a text on the theoretical and experimental aspects of transmission electron microscopy and has chapters on the reciprocal lattice, electron diffraction (both kinematic and dynamic), and high-resolution electron microscopy.Electron diffraction is emphasized, especially its use for structure analysis of poorly crystalline and fine-grained phases not readily determined by the more exact X ray diffraction method. Two methods of electron diffraction are discussed: selected area electron diffraction (SAED) and oblique-texture electron diffraction (OTED); the latter technique is rarely used in the west and is never discussed in western electron microscopy texts. A SAED pattern is formed by isolating a small micrometer-size area with an aperture and obtaining single-crystal patterns from the diffracted beams. By tilting the sample and obtaining many patterns, a complete picture of the reciprocal lattice can be taken. An OTED pattern is formed when the incident electron beam passes through an inclined preparation consisting of a great number of thin platy crystals lying normal to the texture axis (axis normal to the support grid). To form an OTED pattern, the plates must all lie on a common face, such as a basal plane in phyllosilicates. Upon tilting the plates, an elliptical powder diffraction pattern is formed. Intensities measured from these patterns are used for a structural analysis of the platy minerals.

  15. High resolution electron microscopy and spectroscopy of ferritin in thin window liquid cells

    NASA Astrophysics Data System (ADS)

    Wang, Canhui; Qiao, Qiao; Shokuhfar, Tolou; Klie, Robert

    2014-03-01

    In-situ transmission electron microscopy (TEM) has seen a dramatic increase in interest in recent years with the commercial development of liquid and gas stages. High-resolution TEM characterization of samples in a liquid environment remains limited by radiation damage and loss of resolution due to the thick window-layers required by the in-situ stages. We introduce thin-window static-liquid cells that enable sample imaging with atomic resolution and electron energy-loss (EEL) spectroscopy with 1.3 nm resolution. Using this approach, atomic and electronic structures of biological samples such as ferritin is studied via in-situ transmission electron microscopy experiments. Ferritin in solution is encapsulated using the static liquid cells with reduced window thickness. The integrity of the thin window liquid cell is maintained by controlling the electron dose rate. Radiation damage of samples, such as liquid water and protein, is quantitatively studied to allow precision control of radiation damage level within the liquid cells. Biochemical reactions, such as valence change of the iron in a functioning ferritin, is observed and will be quantified. Relevant biochemical activity: the release and uptake of Fe atoms through the channels of ferritin protein shell is also imaged at atomic resolution. This work is funded by Michigan Technological University. The UIC JEOL JEM-ARM200CF is supported by an MRI-R2 grant from the National Science Foundation (Grant No. DMR-0959470).

  16. Achieving atomic resolution magnetic dichroism by controlling the phase symmetry of an electron probe

    DOE PAGES

    Rusz, Jan; Idrobo, Juan -Carlos; Bhowmick, Somnath

    2014-09-30

    The calculations presented here reveal that an electron probe carrying orbital angular momentum is just a particular case of a wider class of electron beams that can be used to measure electron magnetic circular dichroism (EMCD) with atomic resolution. It is possible to obtain an EMCD signal with atomic resolution by simply breaking the symmetry of the electron probe phase front using the aberration-corrected optics of a scanning transmission electron microscope. The probe’s required phase distribution depends on the sample’s magnetic symmetry and crystal structure. The calculations indicate that EMCD signals that use the electron probe’s phase are as strongmore » as those obtained by nanodiffraction methods.« less

  17. Achieving atomic resolution magnetic dichroism by controlling the phase symmetry of an electron probe

    SciTech Connect

    Rusz, Jan; Idrobo, Juan -Carlos; Bhowmick, Somnath

    2014-09-30

    The calculations presented here reveal that an electron probe carrying orbital angular momentum is just a particular case of a wider class of electron beams that can be used to measure electron magnetic circular dichroism (EMCD) with atomic resolution. It is possible to obtain an EMCD signal with atomic resolution by simply breaking the symmetry of the electron probe phase front using the aberration-corrected optics of a scanning transmission electron microscope. The probe’s required phase distribution depends on the sample’s magnetic symmetry and crystal structure. The calculations indicate that EMCD signals that use the electron probe’s phase are as strong as those obtained by nanodiffraction methods.

  18. Highlighting material structure with transmission electron diffraction correlation coefficient maps.

    PubMed

    Kiss, Ákos K; Rauch, Edgar F; Lábár, János L

    2016-04-01

    Correlation coefficient maps are constructed by computing the differences between neighboring diffraction patterns collected in a transmission electron microscope in scanning mode. The maps are shown to highlight material structural features like grain boundaries, second phase particles or dislocations. The inclination of the inner crystal interfaces are directly deduced from the resulting contrast.

  19. In situ nanoindentation in a transmission electron microscope

    SciTech Connect

    Minor, Andrew M.

    2002-01-01

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

  20. Nanowire growth kinetics in aberration corrected environmental transmission electron microscopy

    SciTech Connect

    Chou, Yi -Chia; Panciera, Federico; Reuter, Mark C.; Stach, Eric A.; Ross, Frances M.

    2016-03-15

    Here, we visualize atomic level dynamics during Si nanowire growth using aberration corrected environmental transmission electron microscopy, and compare with lower pressure results from ultra-high vacuum microscopy. We discuss the importance of higher pressure observations for understanding growth mechanisms and describe protocols to minimize effects of the higher pressure background gas.

  1. Transmission electron microscopy of subsolidus oxidation and weathering of olivine

    USGS Publications Warehouse

    Banfield, J.F.; Veblen, D.R.; Jones, B.F.

    1990-01-01

    Olivine crystals in basaltic andesites which crop out in the Abert Rim, south-central Oregon have been studied by high-resolution and analytical transmission electron microscopy. The observations reveal three distinct assemblages of alteration products that seem to correspond to three episodes of olivine oxidation. The olivine crystals contain rare, dense arrays of coherently intergrown Ti-free magnetite and inclusions of a phase inferred to be amorphous silica. We interpret this first assemblage to be the product of an early subsolidus oxidation event in the lava. The second olivine alteration assemblage contains complex ordered intergrowths on (001) of forsterite-rich olivine and laihunite (distorted olivine structure with Fe3+ charge balanced by vacancies). Based on experimental results for laihunite synthesis (Kondoh et al. 1985), these intergrowths probably formed by olivine oxidation between 400 and 800??C. The third episode of alteration involves the destruction of olivine by low-temperature hydrothermal alteration and weathering. Elongate etch-pits and channels in the margins of fresh olivine crystals contain semi-oriented bands of smectite. Olivine weathers to smectite and hematite, and subsequently to arrays of oriented hematite crystals. The textures resemble those reported by Eggleton (1984) and Smith et al. (1987). We find no evidence for a metastable phase intermediate between olivine and smectite ("M" - Eggleton 1984). The presence of laihunite exerts a strong control on the geometry of olivine weathering. Single laihunite layers and laihunite-forsteritic olivine intergrowths increase the resistance of crystals to weathering. Preferential development of channels between laihunite layers occurs where growth of laihunite produced compositional variations in olivine, rather than where coherency-strain is associated with laihunite-olivine interfaces. ?? 1990 Springer-Verlag.

  2. Liquid scanning transmission electron microscopy: Nanoscale imaging in micrometers-thick liquids

    NASA Astrophysics Data System (ADS)

    Schuh, Tobias; de Jonge, Niels

    2014-02-01

    Scanning transmission electron microscopy (STEM) of specimens in liquid is possible using a microfluidic chamber with thin silicon nitride windows. This paper includes an analytic equation of the resolution as a function of the sample thickness and the vertical position of an object in the liquid. The equipment for STEM of liquid specimen is briefly described. STEM provides nanometer resolution in micrometer-thick liquid layers with relevance for both biological research and materials science. Using this technique, we investigated tagged proteins in whole eukaryotic cells, and gold nanoparticles in liquid with time-lapse image series. Possibly future applications are discussed. xml:lang="fr"

  3. Writing silica structures in liquid with scanning transmission electron microscopy.

    PubMed

    van de Put, Marcel W P; Carcouët, Camille C M C; Bomans, Paul H H; Friedrich, Heiner; de Jonge, Niels; Sommerdijk, Nico A J M

    2015-02-04

    Silica nanoparticles are imaged in solution with scanning transmission electron microscopy (STEM) using a liquid cell with silicon nitride (SiN) membrane windows. The STEM images reveal that silica structures are deposited in well-defined patches on the upper SiN membranes upon electron beam irradiation. The thickness of the deposits is linear with the applied electron dose. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) demonstrate that the deposited patches are a result of the merging of the original 20 nm-diameter nanoparticles, and that the related surface roughness depends on the electron dose rate used. Using this approach, sub-micrometer scale structures are written on the SiN in liquid by controlling the electron exposure as function of the lateral position.

  4. Molecular interactions on single-walled carbon nanotubes revealed by high-resolution transmission microscopy

    PubMed Central

    Umeyama, Tomokazu; Baek, Jinseok; Sato, Yuta; Suenaga, Kazu; Abou-Chahine, Fawzi; Tkachenko, Nikolai V.; Lemmetyinen, Helge; Imahori, Hiroshi

    2015-01-01

    The close solid-state structure–property relationships of organic π−aromatic molecules have attracted interest due to their implications for the design of organic functional materials. In particular, a dimeric structure, that is, a unit consisting of two molecules, is required for precisely evaluating intermolecular interactions. Here, we show that the sidewall of a single-walled carbon nanotube (SWNT) represents a unique molecular dimer platform that can be directly visualized using high-resolution transmission electron microscopy. Pyrene is chosen as the π−aromatic molecule; its dimer is covalently linked to the SWNT sidewalls by aryl addition. Reflecting the orientation and separation of the two molecules, the pyrene dimer on the SWNT exhibits characteristic optical and photophysical properties. The methodology discussed here—form and probe molecular dimers—is highly promising for the creation of unique models and provides indispensable and fundamental information regarding molecular interactions. PMID:26173983

  5. Foucault imaging by using non-dedicated transmission electron microscope

    NASA Astrophysics Data System (ADS)

    Taniguchi, Yoshifumi; Matsumoto, Hiroaki; Harada, Ken

    2012-08-01

    An electron optical system for observing Foucault images was constructed using a conventional transmission electron microscope without any special equipment for Lorentz microscopy. The objective lens was switched off and an electron beam was converged by a condenser optical system to the crossover on the selected area aperture plane. The selected area aperture was used as an objective aperture to select the deflected beam for Foucault mode, and the successive image-forming lenses were controlled for observation of the specimen images. The irradiation area on the specimen was controlled by selecting the appropriate diameter of the condenser aperture.

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

    PubMed

    Wu, M; Davidson, N

    1981-11-01

    A transmission electron microscope method for gene mapping by in situ hybridization to Drosophila polytene chromosomes has been developed. As electron-opaque labels, we use colloidal gold spheres having a diameter of 25 nm. The spheres are coated with a layer of protein to which Escherichia coli single-stranded DNA is photochemically crosslinked. Poly(dT) tails are added to the 3' OH ends of these DNA strands, and poly(dA) tails are added to the 3' OH ends of a fragmented cloned Drosophila DNA. These probe--dA strands are hybridized in situ to polytene chromosome squashes. Gold spheres are linked to the hybridized probe--dA strands by A.T base pairing. The sphere positions relative to the chromosome bands can be observed by transmission electron microscopy. The method shows low background and high resolution.

  7. Transmission of electrons inside the cryogenic pumps of ITER injector

    SciTech Connect

    Veltri, P. Sartori, E.

    2016-02-15

    Large cryogenic pumps are installed in the vessel of large neutral beam injectors (NBIs) used to heat the plasma in nuclear fusion experiments. The operation of such pumps can be compromised by the presence of stray secondary electrons that are generated along the beam path. In this paper, we present a numerical model to analyze the propagation of the electrons inside the pump. The aim of the study is to quantify the power load on the active pump elements, via evaluation of the transmission probabilities across the domain of the pump. These are obtained starting from large datasets of particle trajectories, obtained by numerical means. The transmission probability of the electrons across the domain is calculated for the NBI of the ITER and for its prototype Megavolt ITer Injector and Concept Advancement (MITICA) and the results are discussed.

  8. Synergy between transmission electron microscopy and powder diffraction: application to modulated structures.

    PubMed

    Batuk, Dmitry; Batuk, Maria; Abakumov, Artem M; Hadermann, Joke

    2015-04-01

    The crystal structure solution of modulated compounds is often very challenging, even using the well established methodology of single-crystal X-ray crystallography. This task becomes even more difficult for materials that cannot be prepared in a single-crystal form, so that only polycrystalline powders are available. This paper illustrates that the combined application of transmission electron microscopy (TEM) and powder diffraction is a possible solution to the problem. Using examples of anion-deficient perovskites modulated by periodic crystallographic shear planes, it is demonstrated what kind of local structural information can be obtained using various TEM techniques and how this information can be implemented in the crystal structure refinement against the powder diffraction data. The following TEM methods are discussed: electron diffraction (selected area electron diffraction, precession electron diffraction), imaging (conventional high-resolution TEM imaging, high-angle annular dark-field and annular bright-field scanning transmission electron microscopy) and state-of-the-art spectroscopic techniques (atomic resolution mapping using energy-dispersive X-ray analysis and electron energy loss spectroscopy).

  9. High Speed, Radiation Hard CMOS Pixel Sensors for Transmission Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Contarato, Devis; Denes, Peter; Doering, Dionisio; Joseph, John; Krieger, Brad

    CMOS monolithic active pixel sensors are currently being established as the technology of choice for new generation digital imaging systems in Transmission Electron Microscopy (TEM). A careful sensor design that couples μm-level pixel pitches with high frame rate readout and radiation hardness to very high electron doses enables the fabrication of direct electron detectors that are quickly revolutionizing high-resolution TEM imaging in material science and molecular biology. This paper will review the principal characteristics of this novel technology and its advantages over conventional, optically-coupled cameras, and retrace the sensor development driven by the Transmission Electron Aberration corrected Microscope (TEAM) project at the LBNL National Center for Electron Microscopy (NCEM), illustrating in particular the imaging capabilities enabled by single electron detection at high frame rate. Further, the presentation will report on the translation of the TEAM technology to a finer feature size process, resulting in a sensor with higher spatial resolution and superior radiation tolerance currently serving as the baseline for a commercial camera system.

  10. Transmission electron microscopy investigation of auto catalyst and cobalt germanide

    NASA Astrophysics Data System (ADS)

    Sun, Haiping

    The modern ceria-zirconia based catalysts are used in automobiles to reduce exhaust pollutants. Cobalt germanides have potential applications as electrical contacts in the future Ge-based semiconductor devices. In this thesis, transmission electron microscopy (TEM) techniques were used to study the atomic scale interactions between metallic nanostructures and crystalline substrates in the two material systems mentioned above. The model catalyst samples consisted of precious metal nano-particles (Pd, Rh) supported on the surface of (Ce,Zr)O2 thin films. The response of the microstructure of the metal-oxide interface to the reduction and oxidation treatments was investigated by cross-sectional high resolution TEM. Atomic detail of the metal-oxide interface was obtained. It was found that Pd and Rh showed different sintering and interaction behaviors on the oxide surface. The preferred orientation of Pd particles in this study was Pd(111)//CZO(111). Partial encapsulation of Pd particles by reduced (Ce,Zr)O 2 surface was observed and possible mechanisms of the encapsulation were discussed. The characteristics of the metal-oxide interaction depend on the properties of the oxide, as well as their relative orientation. The results provide experimental evidence for understanding the thermodynamics of the equilibrium morphology of a solid particle supported on a solid surface that is not considered as inert. The reaction of Co with Ge to form epitaxial Co5Ge7 was studied by in situ ultra-high vacuum (UHV) TEM using two methods. One was reactive deposition of Co on Ge, in which the Ge substrate was maintained at 350°C during deposition. The other method was solid state reaction, in which the deposition of Co on Ge was carried out at room temperature followed by annealing to higher temperatures. During reactive deposition, the deposited Co reacted with Ge to form nanosized 3D Co 5Ge7 islands. During solid state reaction, a continuous epitaxial Co5Ge7 film on the (001) Ge

  11. Secondary electron imaging of monolayer materials inside a transmission electron microscope

    SciTech Connect

    Cretu, Ovidiu Lin, Yung-Chang; Suenaga, Kazutomo

    2015-08-10

    A scanning transmission electron microscope equipped with a backscattered and secondary electron detector is shown capable to image graphene and hexagonal boron nitride monolayers. Secondary electron contrasts of the two lightest monolayer materials are clearly distinguished from the vacuum level. A signal difference between these two materials is attributed to electronic structure differences, which will influence the escape probabilities of the secondary electrons. Our results show that the secondary electron signal can be used to distinguish between the electronic structures of materials with atomic layer sensitivity, enhancing its applicability as a complementary signal in the analytical microscope.

  12. Interaction of electrons with light metal hydrides in the transmission electron microscope.

    PubMed

    Wang, Yongming; Wakasugi, Takenobu; Isobe, Shigehito; Hashimoto, Naoyuki; Ohnuki, Somei

    2014-12-01

    Transmission electron microscope (TEM) observation of light metal hydrides is complicated by the instability of these materials under electron irradiation. In this study, the electron kinetic energy dependences of the interactions of incident electrons with lithium, sodium and magnesium hydrides, as well as the constituting element effect on the interactions, were theoretically discussed, and electron irradiation damage to these hydrides was examined using in situ TEM. The results indicate that high incident electron kinetic energy helps alleviate the irradiation damage resulting from inelastic or elastic scattering of the incident electrons in the TEM. Therefore, observations and characterizations of these materials would benefit from increased, instead decreased, TEM operating voltage.

  13. Atomic scale characterization of semiconductor interfaces by scanning transmission electron microscopy

    SciTech Connect

    Pennycook, S.J.; Chisholm, M.F.; Duscher, G.; Maiti, A.; Pantelides, S.T.

    1997-05-01

    Recently, the scanning transmission electron microscope has become capable of forming electron probes of atomic dimensions. Through the technique of Z-contrast imaging, it is now possible to form atomic resolution images with high compositional sensitivity from which atomic column positions can be directly determined. An incoherent image of this nature also allows atomic resolution chemical analysis to be performed, by locating the probe over particular columns or planes seen in the image while electron energy loss spectra are collected. These powerful techniques, combined with atomic-scale calculations, constitute a powerful probe of the structural, kinetic and thermodynamic properties of complex materials. The authors show the direct observation of As segregated to specific sites in a Si grain boundary, and present a candidate model for the structure of the Si/SiO{sub 2} interface.

  14. Concurrent in situ ion irradiation transmission electron microscope

    SciTech Connect

    Hattar, K.; Bufford, D. C.; Buller, D. L.

    2014-08-29

    An in situ ion irradiation transmission electron microscope has been developed and is operational at Sandia National Laboratories. This facility permits high spatial resolution, real time observation of electron transparent samples under ion irradiation, implantation, mechanical loading, corrosive environments, and combinations thereof. This includes the simultaneous implantation of low-energy gas ions (0.8–30 keV) during high-energy heavy ion irradiation (0.8–48 MeV). In addition, initial results in polycrystalline gold foils are provided to demonstrate the range of capabilities.

  15. Transmission electron microscopy analysis of skin lesions from sporotrichosis epidemic in Rio de Janeiro, Brazil.

    PubMed

    Ferreira, Cassio Porto; Oliveira de Almeida, Ana Cristina; Corte-Real, Suzana

    2015-02-01

    Transmission electron microscopy can yield useful information in a range of scientific fields; it is capable of imaging at a significantly higher resolution than light microscopes and has been a very useful tool in the identification of morphological changes of the dermis as well as assessment of changes in the extracellular matrix. Our aim is to characterize by electron microscopy the cellular profile of lesions caused by Sporothrix schenckii from the sporotrichosis epidemic in its zoonotic form that occurs in Rio de Janeiro, Brazil.

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

    SciTech Connect

    Kim, Suhyun; Kim, Joong Jung; Jung, Younheum; Lee, Kyungwoo; Byun, Gwangsun; Hwang, KyoungHwan; Lee, Sunyoung; Lee, Kyupil

    2013-09-15

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

  17. New views of materials through aberration-corrected scanning transmission electron microscopy.

    PubMed

    Pennycook, S J; Varela, M

    2011-01-01

    The successful correction of third-order and, more recently, fifth-order aberrations has enormously enhanced the capabilities of the scanning transmission electron microscope (STEM), by not only achieving record resolution, but also allowing near 100% efficiency for electron energy loss spectroscopy, and higher currents for two-dimensional spectrum imaging. These advances have meant that the intrinsic advantages of the STEM, incoherent imaging and simultaneous collection of multiple complementary images can now give new insights into many areas of materials physics. Here, we review a number of examples, mostly from the field of complex oxides, and look towards new directions for the future.

  18. Defects in paramagnetic Co-doped ZnO films studied by transmission electron microscopy

    SciTech Connect

    Kovacs, Andras; Ney, A.; Duchamp, Martial; Ney, V.; Boothroyd, Chris; Galindo, Pedro L.; Kaspar, Tiffany C.; Chambers, Scott A.; Dunin-Borkowski, Rafal

    2013-12-23

    We have studied planar defects in epitaxial Co:ZnO dilute magnetic semiconductor thin films deposited on c-plane sapphire (Al2O3) and the Co:ZnO/Al2O3 interface structure at atomic resolution using aberration-corrected transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS). Comparing Co:ZnO samples deposited by pulsed laser deposition and reactive magnetron sputtering, both exhibit extrinsic stacking faults, incoherent interface structures, and compositional variations within the first 3-4 Co:ZnO layers at the interface.. In addition, we have measured the local strain which reveals the lattice distortion around the stacking faults.

  19. Electron and hole transmission through superconductor — Normal metal interfaces

    NASA Astrophysics Data System (ADS)

    Gloos, Kurt; Tuuli, Elina

    2013-05-01

    We have investigated the transmission of electrons and holes through interfaces between superconducting aluminum ( T c = 1.2K) and various normal non-magnetic metals (copper, gold, palladium, platinum, and silver) using Andreev-reflection spectroscopy at T = 0.1K. We analysed the point contacts with the modified BTK theory that includes Dynes' lifetime as a fitting parameter Γ in addition to superconducting energy gap 2Δ and normal reflection described by Z. For contact areas from 1 nm2 to 10000nm2 the BTK Z parameter was 0.5, corresponding to transmission coefficients of about 80%, independent of the normal metal. The very small variation of Z indicates that the interfaces have a negligible dielectric tunneling barrier. Fermi surface mismatch does not account for the observed transmission coefficient.

  20. Electron-beam-induced ferroelectric domain behavior in the transmission electron microscope: Toward deterministic domain patterning

    NASA Astrophysics Data System (ADS)

    Hart, James L.; Liu, Shi; Lang, Andrew C.; Hubert, Alexander; Zukauskas, Andrius; Canalias, Carlota; Beanland, Richard; Rappe, Andrew M.; Arredondo, Miryam; Taheri, Mitra L.

    2016-11-01

    We report on transmission electron microscope beam-induced ferroelectric domain nucleation and motion. While previous observations of this phenomenon have been reported, a consistent theory explaining induced domain response is lacking, and little control over domain behavior has been demonstrated. We identify positive sample charging, a result of Auger and secondary electron emission, as the underlying mechanism driving domain behavior. By converging the electron beam to a focused probe, we demonstrate controlled nucleation of nanoscale domains. Molecular dynamics simulations performed are consistent with experimental results, confirming positive sample charging and reproducing the result of controlled domain nucleation. Furthermore, we discuss the effects of sample geometry and electron irradiation conditions on induced domain response. These findings elucidate past reports of electron beam-induced domain behavior in the transmission electron microscope and provide a path towards more predictive, deterministic domain patterning through electron irradiation.

  1. Transfer-printing of single DNA molecule arrays on graphene for high resolution electron imaging and analysis

    PubMed Central

    Cerf, Aline; Alava, Thomas; Barton, Robert A.; Craighead, Harold G.

    2011-01-01

    Graphene represents the ultimate substrate for high-resolution transmission electron microscopy, but the deposition of biological samples on this highly hydrophobic material has until now been a challenge. We present a reliable method for depositing ordered arrays of individual elongated DNA molecules on single-layer graphene substrates for high resolution electron beam imaging and electron energy loss spectroscopy analysis. This method is a necessary step towards the observation of single elongated DNA molecules with single base spatial resolution to directly read genetic and epigenetic information. PMID:21919532

  2. Formation of bimetallic clusters in superfluid helium nanodroplets analysed by atomic resolution electron tomography

    PubMed Central

    Haberfehlner, Georg; Thaler, Philipp; Knez, Daniel; Volk, Alexander; Hofer, Ferdinand; Ernst, Wolfgang E.; Kothleitner, Gerald

    2015-01-01

    Structure, shape and composition are the basic parameters responsible for properties of nanoscale materials, distinguishing them from their bulk counterparts. To reveal these in three dimensions at the nanoscale, electron tomography is a powerful tool. Advancing electron tomography to atomic resolution in an aberration-corrected transmission electron microscope remains challenging and has been demonstrated only a few times using strong constraints or extensive filtering. Here we demonstrate atomic resolution electron tomography on silver/gold core/shell nanoclusters grown in superfluid helium nanodroplets. We reveal morphology and composition of a cluster identifying gold- and silver-rich regions in three dimensions and we estimate atomic positions without using any prior information and with minimal filtering. The ability to get full three-dimensional information down to the atomic scale allows understanding the growth and deposition process of the nanoclusters and demonstrates an approach that may be generally applicable to all types of nanoscale materials. PMID:26508471

  3. Practical aspects of monochromators developed for transmission electron microscopy

    PubMed Central

    Kimoto, Koji

    2014-01-01

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

  4. Transmission of High-Power Electron Beams Through Small Apertures

    SciTech Connect

    Tschalaer, Christoph; Alarcon, Ricardo O.; Balascuta, S.; Benson, Stephen V.; Bertozzi, William; Boyce, James R.; Cowan, Ray Franklin; Douglas, David R.; Evtushenko, Pavel; Fisher, Peter H.; Ihloff, Ernest E.; Kalantarians, Narbe; Kelleher, Aidan Michael; Legg, Robert A.; Milner, Richard; Neil, George R.; Ou, Longwu; Schmookler, Barak Abraham; Tennant, Christopher D.; Williams, Gwyn P.; Zhang, Shukui

    2013-11-01

    Tests were performed to pass a 100 MeV, 430 kWatt c.w. electron beam from the energy-recovery linac at the Jefferson Laboratory's FEL facility through a set of small apertures in a 127 mm long aluminum block. Beam transmission losses of 3 p.p.m. through a 2 mm diameter aperture were maintained during a 7 hour continuous run.

  5. High Brightness and high polarization electron source using transmission photocathode

    SciTech Connect

    Yamamoto, Naoto; Jin Xiuguang; Ujihara, Toru; Takeda, Yoshikazu; Mano, Atsushi; Nakagawa, Yasuhide; Nakanishi, Tsutomu; Okumi, Shoji; Yamamoto, Masahiro; Konomi, Taro; Ohshima, Takashi; Saka, Takashi; Kato, Toshihiro; Horinaka, Hiromichi; Yasue, Tsuneo; Koshikawa, Takanori

    2009-08-04

    A transmission photocathode was fabricated based on GaAs-GaAsP strained superlattice layers on a GaP substrate and a 20 kV-gun was built to generate the polarized electron beams with the diameter of a few micro-meter. As the results, the reduced brightness of 1.3x10{sup 7} A/cm{sup 2}/sr and the polarization of 90% were achieved.

  6. Studying localized corrosion using liquid cell transmission electron microscopy

    SciTech Connect

    Chee, See Wee; Pratt, Sarah H.; Hattar, Khalid; Duquette, David; Ross, Frances M.; Hull, Robert

    2014-11-07

    Using liquid cell transmission electron microscopy (LCTEM), localized corrosion of Cu and Al thin films immersed in aqueous NaCl solutions was studied. We demonstrate that potentiostatic control can be used to initiate pitting and that local compositional changes, due to focused ion beam implantation of Au+ ions, can modify the corrosion susceptibility of Al films. Likewise, a discussion on strategies to control the onset of pitting is also presented.

  7. Studying localized corrosion using liquid cell transmission electron microscopy

    DOE PAGES

    Chee, See Wee; Pratt, Sarah H.; Hattar, Khalid; ...

    2014-11-07

    Using liquid cell transmission electron microscopy (LCTEM), localized corrosion of Cu and Al thin films immersed in aqueous NaCl solutions was studied. We demonstrate that potentiostatic control can be used to initiate pitting and that local compositional changes, due to focused ion beam implantation of Au+ ions, can modify the corrosion susceptibility of Al films. Likewise, a discussion on strategies to control the onset of pitting is also presented.

  8. Reciprocity relations in transmission electron microscopy: A rigorous derivation.

    PubMed

    Krause, Florian F; Rosenauer, Andreas

    2017-01-01

    A concise derivation of the principle of reciprocity applied to realistic transmission electron microscopy setups is presented making use of the multislice formalism. The equivalence of images acquired in conventional and scanning mode is thereby rigorously shown. The conditions for the applicability of the found reciprocity relations is discussed. Furthermore the positions of apertures in relation to the corresponding lenses are considered, a subject which scarcely has been addressed in previous publications.

  9. Analysis of Electron Beam Damage of Crystalline Pharmaceutical Materials by Transmission Electron Microscopy

    NASA Astrophysics Data System (ADS)

    S'ari, M.; Cattle, J.; Hondow, N.; Blade, H.; Cosgrove, S.; Brydson, R. M.; Brown, A. P.

    2015-10-01

    We have studied the impact of transmission electron microscopy (TEM) and low dose electron diffraction on ten different crystalline pharmaceutical compounds, covering a diverse chemical space and with differing physical properties. The aim was to establish if particular chemical moieties were more susceptible to damage within the electron beam. We have measured crystalline diffraction patterns for each and indexed nine out of ten of them. Characteristic electron dosages are reported for each material, with no apparent correlation between chemical structure and stability within the electron beam. Such low dose electron diffraction protocols are suitable for the study of pharmaceutical compounds.

  10. Applications of 1 MV field-emission transmission electron microscope.

    PubMed

    Tonomura, Akira

    2003-01-01

    A newly developed 1 MV field-emission transmission electron microscope has recently been applied to the field of superconductivity by utilizing its bright and monochromatic field-emission electron beam. This microscope allows individual magnetic vortices inside high-Tc superconductors to be observed, thus, opening the way to investigate the unusual behaviour of vortices, which reflects the anisotropic layered structure of these superconducting materials. One example is the observation of the arrangements of chain vortex lines that are formed when a magnetic field is applied obliquely to the layer plane of the materials.

  11. Transmission electron microscopy of a model crystalline organic, theophylline

    NASA Astrophysics Data System (ADS)

    Cattle, J.; S'ari, M.; Hondow, N.; Abellán, P.; Brown, A. P.; Brydson, R. M. D.

    2015-10-01

    We report on the use of transmission electron microscopy (TEM) to analyse the diffraction patterns of the model crystalline organic theophylline to investigate beam damage in relation to changing accelerating voltage, sample temperature and TEM grid support films. We find that samples deposited on graphene film grids have the longest lifetimes when also held at -190 °C and imaged at 200 kV accelerating voltage. Finally, atomic lattice images are obtained in bright field STEM by working close to the estimated critical electron dose for theophylline.

  12. Free-standing graphene by scanning transmission electron microscopy.

    PubMed

    Song, F Q; Li, Z Y; Wang, Z W; He, L; Han, M; Wang, G H

    2010-11-01

    Free-standing graphene sheets have been imaged by scanning transmission electron microscopy (STEM). We show that the discrete numbers of graphene layers enable an accurate calibration of STEM intensity to be performed over an extended thickness and with single atomic layer sensitivity. We have applied this calibration to carbon nanoparticles with complex structures. This leads to the direct and accurate measurement of the electron mean free path. Here, we demonstrate potentials using graphene sheets as a novel mass standard in STEM-based mass spectrometry.

  13. Transmission Electron Microscopy Study of InN Nanorods

    SciTech Connect

    Liliental-Weber, Z.; Li, X.; Kryliouk, Olga; Park, H.J.; Mangum,J.; Anderson, T.

    2006-07-13

    InN nanorods were grown on a, c-, and r-plane of sapphire and also on Si (111) and GaN (0001) by non-catalytic, template-free hydride metal-organic vapor phase epitaxy and studied by transmission electron microscopy, electron energy loss (EELS) and photoluminescence (PL) at room temperature. These nanocrystals have different shapes and different faceting depending on the substrate used and their crystallographic orientation. EELS measurements have confirmed the high purity of these crystals. The observed PL peak was in the range of 0.9-0.95 eV. The strongest PL intensity was observed for the nanocrystals with the larger diameters.

  14. Precision electron flow measurements in a disk transmission line.

    SciTech Connect

    Clark, Waylon T.; Pelock, Michael D.; Martin, Jeremy Paul; Jackson, Daniel Peter Jr.; Savage, Mark Edward; Stoltzfus, Brian Scott; Mendel, Clifford Will, Jr.; Pointon, Timothy David

    2008-01-01

    An analytic model for electron flow in a system driving a fixed inductive load is described and evaluated with particle in cell simulations. The simple model allows determining the impedance profile for a magnetically insulated transmission line given the minimum gap desired, and the lumped inductance inside the transition to the minimum gap. The model allows specifying the relative electron flow along the power flow direction, including cases where the fractional electron flow decreases in the power flow direction. The electrons are able to return to the cathode because they gain energy from the temporally rising magnetic field. The simulations were done with small cell size to reduce numerical heating. An experiment to compare electron flow to the simulations was done. The measured electron flow is {approx}33% of the value from the simulations. The discrepancy is assumed to be due to a reversed electric field at the cathode because of the inductive load and falling electron drift velocity in the power flow direction. The simulations constrain the cathode electric field to zero, which gives the highest possible electron flow.

  15. High resolution dissociative electron attachment to gas phase adenine

    SciTech Connect

    Huber, D.; Beikircher, M.; Denifl, S.; Zappa, F.; Matejcik, S.; Bacher, A.; Grill, V.; Maerk, T. D.; Scheier, P.

    2006-08-28

    The dissociative electron attachment to the gas phase nucleobase adenine is studied using two different experiments. A double focusing sector field mass spectrometer is utilized for measurements requiring high mass resolution, high sensitivity, and relative ion yields for all the fragment anions and a hemispherical electron monochromator instrument for high electron energy resolution. The negative ion mass spectra are discussed at two different electron energies of 2 and 6 eV. In contrast to previous gas phase studies a number of new negative ions are discovered in the mass spectra. The ion efficiency curves for the negative ions of adenine are measured for the electron energy range from about 0 to 15 eV with an electron energy resolution of about 100 meV. The total anion yield derived via the summation of all measured fragment anions is compared with the total cross section for negative ion formation measured recently without mass spectrometry. For adenine the shape of the two cross section curves agrees well, taking into account the different electron energy resolutions; however, for thymine some peculiar differences are observed.

  16. Recent developments of the in situ wet cell technology for transmission electron microscopies

    NASA Astrophysics Data System (ADS)

    Chen, Xin; Li, Chang; Cao, Hongling

    2015-03-01

    In situ wet cells for transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) allow studying structures and processes in a liquid environment with high temporal and spatial resolutions, and have been attracting increasing research interests in many fields. In this review, we highlight the structural and functional developments of the wet cells for TEM and STEM. One of the key features of the wet cells is the sealing technique used to isolate the liquid sample from the TEM/STEM vacuum environments, thus the existing in situ wet cells are grouped by different sealing methods. In this study, the advantages and shortcomings of each type of in situ wet cells are discussed, the functional developments of different wet cells are presented, and the future trends of the wet cell technology are addressed. It is suggested that in the future the in situ wet cell TEM/STEM technology will have an increasing impact on frontier nanoscale research.

  17. A specimen preparation technique for plane-view studies of surfaces using transmission electron microscopy.

    PubMed

    Foss, Steinar; Taftø, Johan; Haakenaasen, Randi

    2010-01-01

    A method for preparing plane-view transmission electron microscope (TEM) samples is presented. With this inclined pseudo-plane-view technique, the undisturbed surface of the sample can be studied in plane view. Thus, nanostructures on the surface of a substrate can be studied with TEM in much the same way as with scanning electron microscopy (SEM), but in transmission at a much higher spatial resolution and with the opportunity of performing nanoscale diffraction. A glued sandwich with two surfaces facing each other was thinned at a low angle relative to the surfaces. The resultant construction contained thin wedges of the surfaces upon which it was possible to do TEM analysis. SEM analysis before and TEM analysis after such sample preparation was found to be consistent.

  18. Liquid scanning transmission electron microscopy: imaging protein complexes in their native environment in whole eukaryotic cells.

    PubMed

    Peckys, Diana B; de Jonge, Niels

    2014-04-01

    Scanning transmission electron microscopy (STEM) of specimens in liquid, so-called Liquid STEM, is capable of imaging the individual subunits of macromolecular complexes in whole eukaryotic cells in liquid. This paper discusses this new microscopy modality within the context of state-of-the-art microscopy of cells. The principle of operation and equations for the resolution are described. The obtained images are different from those acquired with standard transmission electron microscopy showing the cellular ultrastructure. Instead, contrast is obtained on specific labels. Images can be recorded in two ways, either via STEM at 200 keV electron beam energy using a microfluidic chamber enclosing the cells, or via environmental scanning electron microscopy at 30 keV of cells in a wet environment. The first series of experiments involved the epidermal growth factor receptor labeled with gold nanoparticles. The labels were imaged in whole fixed cells with nanometer resolution. Since the cells can be kept alive in the microfluidic chamber, it is also feasible to detect the labels in unfixed, live cells. The rapid sample preparation and imaging allows studies of multiple whole cells.

  19. Choice of operating voltage for a transmission electron microscope.

    PubMed

    Egerton, R F

    2014-10-01

    An accelerating voltage of 100-300kV remains a good choice for the majority of TEM or STEM specimens, avoiding the expense of high-voltage microscopy but providing the possibility of atomic resolution even in the absence of lens-aberration correction. For specimens thicker than a few tens of nm, the image intensity and scattering contrast are likely to be higher than at lower voltage, as is the visibility of ionization edges below 1000eV (as required for EELS elemental analysis). In thick (>100nm) specimens, higher voltage ensures less beam broadening and better spatial resolution for STEM imaging and EDX spectroscopy. Low-voltage (e.g. 30kV) TEM or STEM is attractive for a very thin (e.g. 10nm) specimen, as it provides higher scattering contrast and fewer problems for valence-excitation EELS. Specimens that are immune to radiolysis suffer knock-on damage at high current densities, and this form of radiation damage can be reduced or avoided by choosing a low accelerating voltage. Low-voltage STEM with an aberration-corrected objective lens (together with a high-angle dark-field detector and/or EELS) offers atomic resolution and elemental identification from very thin specimens. Conventional TEM can provide atomic resolution in low-voltage phase-contrast images but requires correction of chromatic aberration and preferably an electron-beam monochromator. Many non-conducting (e.g. organic) specimens damage easily by radiolysis and radiation damage then determines the TEM image resolution. For bright-field scattering contrast, low kV can provide slightly better dose-limited resolution if the specimen is very thin (a few nm) but considerably better resolution is possible from a thicker specimen, for which higher kV is required. Use of a phase plate in a conventional TEM offers the most dose-efficient way of achieving atomic resolution from beam-sensitive specimens.

  20. Local temperature measurements on nanoscale materials using a movable nanothermocouple assembled in a transmission electron microscope

    NASA Astrophysics Data System (ADS)

    Kawamoto, Naoyuki; Wang, Ming-Sheng; Wei, Xianlong; Tang, Dai-Ming; Murakami, Yasukazu; Shindo, Daisuke; Mitome, Masanori; Golberg, Dmitri

    2011-12-01

    A nanoscale thermocouple consisting of merged Cu and Cu-Ni tips is developed for local temperature measurements on advanced nanomaterials by using a probing technique in a high-resolution transmission electron microscope (TEM) equipped with a double probe scanning tunneling microcopy (STM) unit. The fabricated nanothermocouple works as the so-called T-type thermocouple and displays a quick response and high spatial and thermal resolutions. A generated thermoelectromotive force which reflects rapid temperature changes controlled by electron beam intensity alternations on a metal nanoelectrode proves the technique's usefulness for high-precision local temperature measurements. The developed method demonstrates the effectiveness while also measuring temperature changes in Joule heated multi-walled carbon nanotubes (CNTs) and in a modeled electrical conductive composite nanosystem.

  1. Accurate Nanoscale Crystallography in Real-Space Using Scanning Transmission Electron Microscopy.

    PubMed

    Dycus, J Houston; Harris, Joshua S; Sang, Xiahan; Fancher, Chris M; Findlay, Scott D; Oni, Adedapo A; Chan, Tsung-Ta E; Koch, Carl C; Jones, Jacob L; Allen, Leslie J; Irving, Douglas L; LeBeau, James M

    2015-08-01

    Here, we report reproducible and accurate measurement of crystallographic parameters using scanning transmission electron microscopy. This is made possible by removing drift and residual scan distortion. We demonstrate real-space lattice parameter measurements with <0.1% error for complex-layered chalcogenides Bi2Te3, Bi2Se3, and a Bi2Te2.7Se0.3 nanostructured alloy. Pairing the technique with atomic resolution spectroscopy, we connect local structure with chemistry and bonding. Combining these results with density functional theory, we show that the incorporation of Se into Bi2Te3 causes charge redistribution that anomalously increases the van der Waals gap between building blocks of the layered structure. The results show that atomic resolution imaging with electrons can accurately and robustly quantify crystallography at the nanoscale.

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

    SciTech Connect

    Kempton, Eliza M.-R.; Perna, Rosalba; Heng, Kevin

    2014-11-01

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

  3. In Situ Electrochemical Transmission Electron Microscopy for Battery Research

    SciTech Connect

    Mehdi, Beata L.; Gu, Meng; Parent, Lucas R.; Xu, Wu; Nasybulin, Eduard N.; Chen, Xilin; Unocic, Raymond R.; Xu, Pinghong; Welch, David A.; Abellan, Patricia; Zhang, Jiguang; Liu, Jun; Wang, Chong M.; Arslan, Ilke; Evans, James E.; Browning, Nigel D.

    2014-04-01

    The recent development of in situ liquid stages for (scanning) transmission electron microscopes now makes it possible for us to study the details of electrochemical processes under operando conditions. As electrochemical processes are complex, care must be taken to calibrate the system before any in situ/operando observations. In addition, as the electron beam can cause effects that look similar to electrochemical processes at the electrolyte/electrode interface, an understanding of the role of the electron beam in modifying the operando observations must also be understood. In this paper we describe the design, assembly, and operation of an in situ electrochemical cell, paying particular attention to the method for controlling and quantifying the experimental parameters. The use of this system is then demonstrated for the lithiation/delithiation of silicon nanowires.

  4. In-situ electrochemical transmission electron microscopy for battery research.

    PubMed

    Mehdi, B Layla; Gu, Meng; Parent, Lucas R; Xu, Wu; Nasybulin, Eduard N; Chen, Xilin; Unocic, Raymond R; Xu, Pinghong; Welch, David A; Abellan, Patricia; Zhang, Ji-Guang; Liu, Jun; Wang, Chong-Min; Arslan, Ilke; Evans, James; Browning, Nigel D

    2014-04-01

    The recent development of in-situ liquid stages for (scanning) transmission electron microscopes now makes it possible for us to study the details of electrochemical processes under operando conditions. As electrochemical processes are complex, care must be taken to calibrate the system before any in-situ/operando observations. In addition, as the electron beam can cause effects that look similar to electrochemical processes at the electrolyte/electrode interface, an understanding of the role of the electron beam in modifying the operando observations must also be understood. In this paper we describe the design, assembly, and operation of an in-situ electrochemical cell, paying particular attention to the method for controlling and quantifying the experimental parameters. The use of this system is then demonstrated for the lithiation/delithiation of silicon nanowires.

  5. Transmission electron microscopic examination of phosphoric acid fuel cell components

    NASA Technical Reports Server (NTRS)

    Pebler, A.

    1986-01-01

    Transmission electron microscopy (TEM) was used to physically characterize tested and untested phosphoric acid fuel cell (PAFC) components. Those examined included carbon-supported platinum catalysts, carbon backing paper, and Teflon-bonded catalyst layers at various stages of fabrication and after testing in pressurized PAFC's. Applicability of electron diffraction and electron energy loss spectroscopy for identifying the various phases was explored. The discussion focuses on the morphology and size distribution of platinum, the morphology and structural aspects of Teflon in catalyst layers, and the structural evidence of carbon corrosion. Reference is made to other physical characterization techniques where appropriate. A qualitative model of the catalyst layer that emerged from the TEM studies is presented.

  6. Transmission electron microscope characterisation of molar-incisor-hypomineralisation.

    PubMed

    Xie, Zonghan; Kilpatrick, Nicky M; Swain, Michael V; Munroe, Paul R; Hoffman, Mark

    2008-10-01

    Molar-incisor-hypomineralisation (MIH), one of the major developmental defects in dental enamel, is presenting challenge to clinicians due, in part, to the limited understanding of microstructural changes in affected teeth. Difficulties in the preparation of site-specific transmission electron microscope (TEM) specimens are partly responsible for this deficit. In this study, a dual-beam field emission scanning electron microscope (FESEM)/focused ion beam (FIB) milling instrument was used to prepare electron transparent specimens of sound and hypomineralised enamel. Microstructural analysis revealed that the hypomineralised areas in enamel were associated with marked changes in microstructure; loosely packed apatite crystals within prisms and wider sheath regions were identified. Microstructural changes appear to occur during enamel maturation and may be responsible for the dramatic reduction in mechanical properties of the affected regions. An enhanced knowledge of the degradation of structural integrity in hypomineralised enamel could shed light on more appropriate management strategies for these developmental defects.

  7. Effects of instrument imperfections on quantitative scanning transmission electron microscopy.

    PubMed

    Krause, Florian F; Schowalter, Marco; Grieb, Tim; Müller-Caspary, Knut; Mehrtens, Thorsten; Rosenauer, Andreas

    2016-02-01

    Several instrumental imperfections of transmission electron microscopes are characterized and their effects on the results of quantitative scanning electron microscopy (STEM) are investigated and quantified using simulations. Methods to either avoid influences of these imperfections during acquisition or to include them in reference calculations are proposed. Particularly, distortions inflicted on the diffraction pattern by an image-aberration corrector can cause severe errors of more than 20% if not accounted for. A procedure for their measurement is proposed here. Furthermore, afterglow phenomena and nonlinear behavior of the detector itself can lead to incorrect normalization of measured intensities. Single electrons accidentally impinging on the detector are another source of error but can also be exploited for threshold-less calibration of STEM images to absolute dose, incident beam current determination and measurement of the detector sensitivity.

  8. High Resolution Emission and Transmission Imaging Using the Same Detector.

    PubMed

    Panse, Ashish S; Jain, A; Wang, W; Yao, R; Bednarek, D R; Rudin, S

    2010-10-30

    We demonstrate the capability of one detector, the Micro-Angiographic Fluoroscope (MAF) detector, to image for two types of applications: nuclear medicine imaging and radiography. The MAF has 1024 × 1024 pixels with an effective pixel size of 35 microns and is capable of real-time imaging at 30 fps. It has a CCD camera coupled by a fiber-optic taper to a light image intensifier (LII) viewing a 300-micron thick CsI phosphor. The large variable gain of the LII provides quantum-limited operation with little additive instrumentation noise and enables operation in both energy-integrating (EI) and sensitive low-exposure single photon counting (SPC) modes. We used the EI mode to take a radiograph, and the SPC mode to image a custom phantom filled with 1 mCi of I-125. The phantom is made of hot rods with diameters ranging from 0.9 mm to 2.3 mm. A 1 mm diameter parallel hole, medium energy gamma camera collimator was placed between the phantom and the MAF and was moved multiple times at equal intervals in random directions to eliminate the grid pattern corresponding to the collimator septa. Data was acquired at 20 fps. Two algorithms to localize the events were used: 1) simple threshold and 2) a weighted centroid method. Although all the hot rods could be clearly identified, the image generated with the simple threshold method shows more blurring than that with the weighted centroid method. With the diffuse cluster of pixels from each single detection event localized to a single pixel, the weighted centroid method shows improved spatial resolution. A radiograph of the phantom was taken with the same MAF in EI mode without the collimator. It shows clear structural details of the rods. Compared to the radiograph, the sharpness of the emission image is limited by the collimator resolution and could be improved by optimized collimator design. This study demonstrated that the same MAF detector can be used in both radioisotope and x-ray imaging, combining the benefits of each.

  9. Breaking the spherical and chromatic aberration barrier in transmission electron microscopy.

    PubMed

    Freitag, B; Kujawa, S; Mul, P M; Ringnalda, J; Tiemeijer, P C

    2005-02-01

    Since the invention of transmission electron microscopy (TEM) in 1932 (Z. Physik 78 (1932) 318) engineering improvements have advanced system resolutions to levels that are now limited only by the two fundamental aberrations of electron lenses; spherical and chromatic aberration (Z. Phys. 101 (1936) 593). Since both aberrations scale with the dimensions of the lens, research resolution requirements are pushing the designs to lenses with only a few mm space in the pole-piece gap for the specimen. This is in conflict with the demand for more and more space at the specimen, necessary in order to enable novel techniques in TEM, such as He-cooled cryo electron microscopy, 3D-reconstruction through tomography (Science 302 (2003) 1396) TEM in gaseous environments, or in situ experiments (Nature 427 (2004) 426). All these techniques will only be able to achieve Angstrom resolution when the aberration barriers have been overcome. The spherical aberration barrier has recently been broken by introducing spherical aberration correctors (Nature 392 (1998) 392, 418 (2002) 617), but the correction of the remaining chromatic aberrations have proved to be too difficult for the present state of technology (Optik 57 (1980) 73). Here we present an alternative and successful method to eliminate the chromatic blur, which consists of monochromating the TEM beam (Inst. Phys. Conf. Ser. 161 (1999) 191). We show directly interpretable resolutions well below 1A for the first time, which is significantly better than any TEM operating at 200 KV has reached before.

  10. High-resolution threshold photoelectron spectroscopy by electron attachment

    NASA Technical Reports Server (NTRS)

    Ajello, J. M.; Chutjian, A.

    1976-01-01

    A new technique for measuring high-resolution threshold photoelectron spectra of atoms, molecules, and radicals is described. It involves photoionization of a gaseous species, attachment of the threshold, or nearly zero electron to some trapping molecule (here SF6 or CFCl3), and mass detection of the attachment product (SF6/-/ or Cl/-/ respectively). This technique of threshold photoelectron spectroscopy by electron attachment was used to measure the spectra of argon and xenon at 11 meV (FWHM) resolution, and was also applied to CFCl3.

  11. Strain mapping at nanometer resolution using advanced nano-beam electron diffraction

    SciTech Connect

    Ozdol, V. B.; Ercius, P.; Ophus, C.; Ciston, J.; Gammer, C. E-mail: aminor@lbl.gov; Jin, X. G.; Minor, A. M. E-mail: aminor@lbl.gov

    2015-06-22

    We report on the development of a nanometer scale strain mapping technique by means of scanning nano-beam electron diffraction. Only recently possible due to fast acquisition with a direct electron detector, this technique allows for strain mapping with a high precision of 0.1% at a lateral resolution of 1 nm for a large field of view reaching up to 1 μm. We demonstrate its application to a technologically relevant strain-engineered GaAs/GaAsP hetero-structure and show that the method can even be applied to highly defected regions with substantial changes in local crystal orientation. Strain maps derived from atomically resolved scanning transmission electron microscopy images were used to validate the accuracy, precision and resolution of this versatile technique.

  12. Nanocrystal size distribution analysis from transmission electron microscopy images

    NASA Astrophysics Data System (ADS)

    van Sebille, Martijn; van der Maaten, Laurens J. P.; Xie, Ling; Jarolimek, Karol; Santbergen, Rudi; van Swaaij, René A. C. M. M.; Leifer, Klaus; Zeman, Miro

    2015-12-01

    We propose a method, with minimal bias caused by user input, to quickly detect and measure the nanocrystal size distribution from transmission electron microscopy (TEM) images using a combination of Laplacian of Gaussian filters and non-maximum suppression. We demonstrate the proposed method on bright-field TEM images of an a-SiC:H sample containing embedded silicon nanocrystals with varying magnifications and we compare the accuracy and speed with size distributions obtained by manual measurements, a thresholding method and PEBBLES. Finally, we analytically consider the error induced by slicing nanocrystals during TEM sample preparation on the measured nanocrystal size distribution and formulate an equation to correct this effect.We propose a method, with minimal bias caused by user input, to quickly detect and measure the nanocrystal size distribution from transmission electron microscopy (TEM) images using a combination of Laplacian of Gaussian filters and non-maximum suppression. We demonstrate the proposed method on bright-field TEM images of an a-SiC:H sample containing embedded silicon nanocrystals with varying magnifications and we compare the accuracy and speed with size distributions obtained by manual measurements, a thresholding method and PEBBLES. Finally, we analytically consider the error induced by slicing nanocrystals during TEM sample preparation on the measured nanocrystal size distribution and formulate an equation to correct this effect. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06292f

  13. 45 CFR Appendix C to Part 1355 - Electronic Data Transmission Format

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 4 2013-10-01 2013-10-01 false Electronic Data Transmission Format C Appendix C.... 1355, App. C Appendix C to Part 1355—Electronic Data Transmission Format All AFCARS data to be sent... be four semi-annual electronic data transmissions from the title IV-E agency to the...

  14. Improving transmission rates of electronic discharge summaries to GPs.

    PubMed

    Barr, Rory; Chin, Kuen Yeow; Yeong, Keefai

    2013-01-01

    Discharge summaries are a vital tool to communicate information from Hospital to Primary Care teams; updating GPs about what happened during an admission, and handing over care detailing any follow up care required. Historically, Discharge Summaries have been posted to hospitals, increasing costs for hospitals, creating administrative work for GP practices receiving the letters, and resulting in some letters being lost or delayed in reaching the GP, with implications for patient safety if follow up requests are not received and acted upon. In an effort to improve patient care, the Clinical Commissioning Group in Surrey drew up a contract with Ashford and St Peter's Foundation Trust, aiming to increase the percentage of discharge summaries sent electronically from the rate of 9% sent within 24 hours, to over 75%. This contract set targets of 50% in May, 65% in June, and 80% in July. Financial penalties would be imposed if targets were not achieved, starting in June 2013. The Trust set up a working group comprising of doctors, IT personnel and ward PAs to devise a multi-pronged solution to achieve this target. The electronic discharge summary system was reviewed and improvements were designed and developed to make the process of signing off letters easier, and transmission of signed off letters became automated rather than requiring manual transmission by ward PAs. Presentations and leaflets to explain the importance of prompt completion and transmission of discharge summaries were given to Doctors to improve compliance using the revised IT system. Figures on transmission rates were automatically emailed to key stakeholders every day (Ward PAs, Divisional Leads) showing performance on each ward. This helped identify areas requiring more intervention. Areas (e.g. Day Surgery) that had not used electronic discharge summaries were engaged with, and persuaded to take part. As a result, transmission rates of Discharge Summaries within 24 hours of patient discharge

  15. Copper Decoration of Carbon Nanotubes and High Resolution Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Probst, Camille

    A new process of decorating carbon nanotubes with copper was developed for the fabrication of nanocomposite aluminum-nanotubes. The process consists of three stages: oxidation, activation and electroless copper plating on the nanotubes. The oxidation step was required to create chemical function on the nanotubes, essential for the activation step. Then, catalytic nanoparticles of tin-palladium were deposited on the tubes. Finally, during the electroless copper plating, copper particles with a size between 20 and 60 nm were uniformly deposited on the nanotubes surface. The reproducibility of the process was shown by using another type of carbon nanotube. The fabrication of nanocomposites aluminum-nanotubes was tested by aluminum vacuum infiltration. Although the infiltration of carbon nanotubes did not produce the expected results, an interesting electron microscopy sample was discovered during the process development: the activated carbon nanotubes. Secondly, scanning transmitted electron microscopy (STEM) imaging in SEM was analysed. The images were obtained with a new detector on the field emission scanning electron microscope (Hitachi S-4700). Various parameters were analysed with the use of two different samples: the activated carbon nanotubes (previously obtained) and gold-palladium nanodeposits. Influences of working distance, accelerating voltage or sample used on the spatial resolution of images obtained with SMART (Scanning Microscope Assessment and Resolution Testing) were analysed. An optimum working distance for the best spatial resolution related to the sample analysed was found for the imaging in STEM mode. Finally, relation between probe size and spatial resolution of backscattered electrons (BSE) images was studied. An image synthesis method was developed to generate the BSE images from backscattered electrons coefficients obtained with CASINO software. Spatial resolution of images was determined using SMART. The analysis shown that using a probe

  16. Segmentation of virus particle candidates in transmission electron microscopy images.

    PubMed

    Kylberg, G; Uppström, M; Hedlund, K-O; Borgefors, G; Sintorn, I-M

    2012-02-01

    In this paper, we present an automatic segmentation method that detects virus particles of various shapes in transmission electron microscopy images. The method is based on a statistical analysis of local neighbourhoods of all the pixels in the image followed by an object width discrimination and finally, for elongated objects, a border refinement step. It requires only one input parameter, the approximate width of the virus particles searched for. The proposed method is evaluated on a large number of viruses. It successfully segments viruses regardless of shape, from polyhedral to highly pleomorphic.

  17. Transmission Electron Microscopy Of Lipid Vesicles For Drug Delivery

    NASA Astrophysics Data System (ADS)

    Bello, Valentina; Mattei, Giovanni; Mazzoldi, Paolo; Vivenza, Nicoletta; Gasco, Paolo; Idee, Jean Marc; Robic, Caroline; Borsella, Elisabetta

    2010-10-01

    Iron oxides nanocrystals are largely used for biomedical applications due to their high magnetization. Furthermore for in vivo applications these nanoparticles must be covered with a non-toxic material. Inside the numerous nano-systems for drug delivery, lipid structures, such as Solid Lipid Nanoparticles (SLNs), have been largely developed for various administration routes. In this work SLNs and iron-oxide nanocrystals covered with a lipid shell are characterized by Transmission Electron Microscopy. This technique has revealed to be essential to investigate the ultrafine compositional and morphological properties of these systems.

  18. Simultaneous orientation and thickness mapping in transmission electron microscopy

    SciTech Connect

    Tyutyunnikov, Dmitry; Özdöl, V. Burak; Koch, Christoph T.

    2014-12-04

    In this paper we introduce an approach for simultaneous thickness and orientation mapping of crystalline samples by means of transmission electron microscopy. We show that local thickness and orientation values can be extracted from experimental dark-field (DF) image data acquired at different specimen tilts. The method has been implemented to automatically acquire the necessary data and then map thickness and crystal orientation for a given region of interest. We have applied this technique to a specimen prepared from a commercial semiconductor device, containing multiple 22 nm technology transistor structures. The performance and limitations of our method are discussed and compared to those of other techniques available.

  19. Transmission electron microscopy study of thin sections of ultrasmall quantity of cells

    NASA Astrophysics Data System (ADS)

    Volkov, Uryi P.; Konnov, Nikolai P.; Novikova, Olga V.

    2001-10-01

    Transmission electron microscopy investigation of thin sections remains the major method of cells inner structure study with high resolution. However, the present-day technique of cells preparation make it impossible to study a number of biological samples, such as very small quantity of lymph cells of little insects (spiders, fleas, etc.). A new technique of cells preparation has been developed in our lab, which allow to obtain a thin sections of ultra small quantity of cells (less then 100). Structure of lymph cells of flea was investigated by the technique.

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

    PubMed

    Chu, Ming-Wen; Chen, Cheng Hsuan

    2013-06-25

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

  1. The three-dimensional point spread function of aberration-corrected scanning transmission electron microscopy.

    PubMed

    Lupini, Andrew R; de Jonge, Niels

    2011-10-01

    Aberration correction reduces the depth of field in scanning transmission electron microscopy (STEM) and thus allows three-dimensional (3D) imaging by depth sectioning. This imaging mode offers the potential for sub-Ångstrom lateral resolution and nanometer-scale depth sensitivity. For biological samples, which may be many microns across and where high lateral resolution may not always be needed, optimizing the depth resolution even at the expense of lateral resolution may be desired, aiming to image through thick specimens. Although there has been extensive work examining and optimizing the probe formation in two dimensions, there is less known about the probe shape along the optical axis. Here the probe shape is examined in three dimensions in an attempt to better understand the depth resolution in this mode. Examples are presented of how aberrations change the probe shape in three dimensions, and it is found that off-axial aberrations may need to be considered for focal series of large areas. It is shown that oversized or annular apertures theoretically improve the vertical resolution for 3D imaging of nanoparticles. When imaging nanoparticles of several nanometer size, regular STEM can thereby be optimized such that the vertical full-width at half-maximum approaches that of the aberration-corrected STEM with a standard aperture.

  2. Element discrimination in a hexagonal boron nitride nanosheet by aberration corrected transmission electron microscopy.

    PubMed

    Mitome, Masanori; Sawada, Hidetaka; Kondo, Yukihito; Tanishiro, Yasumasa; Takayanagi, Kunio

    2012-11-01

    Boron nitride nanosheets prepared by an exfoliation technique were observed by aberration corrected transmission electron microscopy at 300 kV acceleration voltage. Single boron and nitrogen atoms in a monolayer region were imaged with different image contrast; a boron atom gave 16% less intensity reduction than a nitrogen atom. The number of atoms at each hexagonal ring site was determined by the image intensity that changed discretely with a 0.25-0.30 intensity difference. A double BN sheet was found to have a boron vacancy layer, and a triple BN layer has also a boron deficient layer on the incident surface resulting from the electron beam thinning process. The high sensitivity for atomic species was achieved by the high resolution and a small information limit due to the use of a cold field emission electron source.

  3. In situ transmission electron microscopy for magnetic nanostructures

    NASA Astrophysics Data System (ADS)

    Ngo, Duc-The; Theil Kuhn, Luise

    2016-12-01

    Nanomagnetism is a subject of great interest because of both application and fundamental aspects in which understanding of the physical and electromagnetic structure of magnetic nanostructures is essential to explore the magnetic properties. Transmission electron microscopy (TEM) is a powerful tool that allows understanding of both physical structure and micromagnetic structure of the thin samples at nanoscale. Among TEM techniques, in situ TEM is the state-of-the-art approach for imaging such structures in dynamic experiments, reconstructing a real-time nanoscale picture of the properties-structure correlation. This paper aims at reviewing and discussing in situ TEM magnetic imaging studies, including Lorentz microscopy and electron holography in TEM, applied to the research of magnetic nanostructures.

  4. A transmission electron microscopic study of the Bethany iron meteorite

    NASA Astrophysics Data System (ADS)

    Hasan, F.; Axon, H. J.

    1985-02-01

    The Bethany iron meteorite, which is a part of the Gibeon shower, is a fine octahedrite with zoned plessite fields of various sizes. The optically irresolvable microstructural details inside the plessitic fields have been studied by transmission electron microscopy, and the crystallographic relationships between the primary kamacite (alpha) and the parent taenite (gamma), and between the alpha and gamma particles in the coarse plessite, have been examined using electron diffraction. In the case of primary kamacite, the orientation-relationship with gamma was close to the Nishiyama-Wasserman relationship, whereas, for the plessitic alpha, the orientation-relationship with gamma was close to Kurdjumov-Sachs. It was also found that the (111)-gamma and (110)-alpha planes were not strictly parallel. Additionally, measurements of the composition profile through the zoned plessite have been made using STEM microanalysis technique, and related to microstructure.

  5. Human enamel structure studied by high resolution electron microscopy

    SciTech Connect

    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.

  6. The Potential for Bayesian Compressive Sensing to Significantly Reduce Electron Dose in High Resolution STEM Images

    SciTech Connect

    Stevens, Andrew J.; Yang, Hao; Carin, Lawrence; Arslan, Ilke; Browning, Nigel D.

    2014-02-11

    The use of high resolution imaging methods in the scanning transmission electron microscope (STEM) is limited in many cases by the sensitivity of the sample to the beam and the onset of electron beam damage (for example in the study of organic systems, in tomography and during in-situ experiments). To demonstrate that alternative strategies for image acquisition can help alleviate this beam damage issue, here we apply compressive sensing via Bayesian dictionary learning to high resolution STEM images. These experiments successively reduce the number of pixels in the image (thereby reducing the overall dose while maintaining the high resolution information) and show promising results for reconstructing images from this reduced set of randomly collected measurements. We show that this approach is valid for both atomic resolution images and nanometer resolution studies, such as those that might be used in tomography datasets, by applying the method to images of strontium titanate and zeolites. As STEM images are acquired pixel by pixel while the beam is scanned over the surface of the sample, these post acquisition manipulations of the images can, in principle, be directly implemented as a low-dose acquisition method with no change in the electron optics or alignment of the microscope itself.

  7. Toward 10 meV electron energy-loss spectroscopy resolution for plasmonics.

    PubMed

    Bellido, Edson P; Rossouw, David; Botton, Gianluigi A

    2014-06-01

    Energy resolution is one of the most important parameters in electron energy-loss spectroscopy. This is especially true for measurement of surface plasmon resonances, where high-energy resolution is crucial for resolving individual resonance peaks, in particular close to the zero-loss peak. In this work, we improve the energy resolution of electron energy-loss spectra of surface plasmon resonances, acquired with a monochromated beam in a scanning transmission electron microscope, by the use of the Richardson-Lucy deconvolution algorithm. We test the performance of the algorithm in a simulated spectrum and then apply it to experimental energy-loss spectra of a lithographically patterned silver nanorod. By reduction of the point spread function of the spectrum, we are able to identify low-energy surface plasmon peaks in spectra, more localized features, and higher contrast in surface plasmon energy-filtered maps. Thanks to the combination of a monochromated beam and the Richardson-Lucy algorithm, we improve the effective resolution down to 30 meV, and evidence of success up to 10 meV resolution for losses below 1 eV. We also propose, implement, and test two methods to limit the number of iterations in the algorithm. The first method is based on noise measurement and analysis, while in the second we monitor the change of slope in the deconvolved spectrum.

  8. 14 CFR 221.500 - Transmission of electronic tariffs to subscribers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Transmission of electronic tariffs to... TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS TARIFFS Electronically Filed Tariffs § 221.500 Transmission of electronic tariffs to subscribers. (a) Each filer that files an electronic tariff under...

  9. 14 CFR 221.500 - Transmission of electronic tariffs to subscribers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Transmission of electronic tariffs to... TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS TARIFFS Electronically Filed Tariffs § 221.500 Transmission of electronic tariffs to subscribers. (a) Each filer that files an electronic tariff under...

  10. 76 FR 71044 - International Conference on Harmonisation; E2B(R3) Electronic Transmission of Individual Case...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-16

    ...) Electronic Transmission of Individual Case Safety Reports; Draft Guidance on Implementation; Data Elements...) Electronic Transmission of Individual Case Safety Reports (ICSRs): Implementation Guide--Data Elements...

  11. Efficient linear phase contrast in scanning transmission electron microscopy with matched illumination and detector interferometry

    DOE PAGES

    Ophus, Colin; Ciston, Jim; Pierce, Jordan; ...

    2016-02-29

    The ability to image light elements in soft matter at atomic resolution enables unprecedented insight into the structure and properties of molecular heterostructures and beam-sensitive nanomaterials. In this study, we introduce a scanning transmission electron microscopy technique combining a pre-specimen phase plate designed to produce a probe with structured phase with a high-speed direct electron detector to generate nearly linear contrast images with high efficiency. We demonstrate this method by using both experiment and simulation to simultaneously image the atomic-scale structure of weakly scattering amorphous carbon and strongly scattering gold nanoparticles. Our method demonstrates strong contrast for both materials, makingmore » it a promising candidate for structural determination of heterogeneous soft/hard matter samples even at low electron doses comparable to traditional phase-contrast transmission electron microscopy. Ultimately, simulated images demonstrate the extension of this technique to the challenging problem of structural determination of biological material at the surface of inorganic crystals.« less

  12. Transmission electron microscopy characterisation of 0-D nanomaterials

    NASA Astrophysics Data System (ADS)

    Turner, Stuart Matthew

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

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

    PubMed

    Murata, Kazuyoshi; Esaki, Masatoshi; Ogura, Teru; Arai, Shigeo; Yamamoto, Yuta; Tanaka, Nobuo

    2014-11-01

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

  14. Direct Imaging of Single Cells and Tissue at Subcellular Spatial Resolution Using Transmission Geometry MALDI MS

    PubMed Central

    Zavalin, Andre; Todd, Erik M.; Rawhouser, Patrick D.; Yang, Junhai; Norris, Jeremy L.; Caprioli, Richard M.

    2012-01-01

    The need of cellular and sub-cellular spatial resolution in LDI / MALDI Imaging Mass Spectrometry (IMS) necessitates micron and sub-micron laser spot sizes at biologically relevant sensitivities, introducing significant challenges for MS technology. To this end we have developed a transmission geometry vacuum ion source that allows the laser beam to irradiate the back side of the sample. This arrangement obviates the mechanical / ion optic complications in the source by completely separating the optical lens and ion optic structures. We have experimentally demonstrated the viability of transmission geometry MALDI MS for imaging biological tissues and cells with sub-cellular spatial resolution. Furthermore, we demonstrate that in conjunction with new sample preparation protocols, the sensitivity of this instrument is sufficient to obtain molecular images at sub-micron spatial resolution. PMID:23147833

  15. Factors influencing quantitative liquid (scanning) transmission electron microscopy

    SciTech Connect

    Abellan Baeza, Patricia; Woehl, Taylor J.; Parent, Lucas R.; Browning, Nigel D.; Evans, James E.; Arslan, Ilke

    2014-04-15

    One of the experimental challenges in the study of nanomaterials in liquids in the (scanning) transmission electron microscope ((S)TEM) is gaining quantitative information. A successful experiment in the fluid stage will depend upon the ability to plan for sensitive factors such as the electron dose applied, imaging mode, acceleration voltage, beam-induced solution chemistry changes, and the specifics of solution reactivity. In this paper, we make use of a visual approach to show the extent of damage of different instrumental and experimental factors in liquid samples imaged in the (S)TEM. Previous results as well as new insights are presented to create an overview of beam-sample interactions identified for changing imaging and experimental conditions. This work establishes procedures to understand the effect of the electron beam on a solution, provides information to allow for a deliberate choice of the optimal experimental conditions to enable quantification, and identifies the experimental factors that require further analysis for achieving fully quantitative results in the liquid (S)TEM.

  16. Transmission electron microscopy in molecular structural biology: A historical survey.

    PubMed

    Harris, J Robin

    2015-09-01

    In this personal, historic account of macromolecular transmission electron microscopy (TEM), published data from the 1940s through to recent times is surveyed, within the context of the remarkable progress that has been achieved during this time period. The evolution of present day molecular structural biology is described in relation to the associated biological disciplines. The contribution of numerous electron microscope pioneers to the development of the subject is discussed. The principal techniques for TEM specimen preparation, thin sectioning, metal shadowing, negative staining and plunge-freezing (vitrification) of thin aqueous samples are described, with a selection of published images to emphasise the virtues of each method. The development of digital image analysis and 3D reconstruction is described in detail as applied to electron crystallography and reconstructions from helical structures, 2D membrane crystals as well as single particle 3D reconstruction of icosahedral viruses and macromolecules. The on-going development of new software, algorithms and approaches is highlighted before specific examples of the historical progress of the structural biology of proteins and viruses are presented.

  17. 46 CFR 531.8 - Amendment, correction, cancellation, and electronic transmission errors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... transmission errors. 531.8 Section 531.8 Shipping FEDERAL MARITIME COMMISSION REGULATIONS AFFECTING OCEAN..., cancellation, and electronic transmission errors. (a) Amendment. (1) NSAs may be amended by mutual agreement of.... (c) Electronic transmission errors. (1) An authorized person who experiences a purely...

  18. 46 CFR 530.10 - Amendment, correction, cancellation, and electronic transmission errors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... transmission errors. 530.10 Section 530.10 Shipping FEDERAL MARITIME COMMISSION REGULATIONS AFFECTING OCEAN..., cancellation, and electronic transmission errors. (a) Terms. When used in this section, the following terms... in appendix A to this part. (d) Electronic transmission errors. An authorized person who...

  19. 46 CFR 531.8 - Amendment, correction, cancellation, and electronic transmission errors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... transmission errors. 531.8 Section 531.8 Shipping FEDERAL MARITIME COMMISSION REGULATIONS AFFECTING OCEAN..., cancellation, and electronic transmission errors. (a) Amendment. (1) NSAs may be amended by mutual agreement of.... (c) Electronic transmission errors. (1) An authorized person who experiences a purely...

  20. 46 CFR 530.10 - Amendment, correction, cancellation, and electronic transmission errors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... transmission errors. 530.10 Section 530.10 Shipping FEDERAL MARITIME COMMISSION REGULATIONS AFFECTING OCEAN..., cancellation, and electronic transmission errors. (a) Terms. When used in this section, the following terms... in appendix A to this part. (d) Electronic transmission errors. An authorized person who...

  1. The Effect of Electron Beam Irradiation in Environmental Scanning Transmission Electron Microscopy of Whole Cells in Liquid.

    PubMed

    Hermannsdörfer, Justus; Tinnemann, Verena; Peckys, Diana B; de Jonge, Niels

    2016-06-01

    Whole cells can be studied in their native liquid environment using electron microscopy, and unique information about the locations and stoichiometry of individual membrane proteins can be obtained from many cells thus taking cell heterogeneity into account. Of key importance for the further development of this microscopy technology is knowledge about the effect of electron beam radiation on the samples under investigation. We used environmental scanning electron microscopy (ESEM) with scanning transmission electron microscopy (STEM) detection to examine the effect of radiation for whole fixed COS7 fibroblasts in liquid. The main observation was the localization of nanoparticle labels attached to epidermal growth factor receptors (EGFRs). It was found that the relative distances between the labels remained mostly unchanged (<1.5%) for electron doses ranging from the undamaged native state at 10 e-/Å2 toward 103 e-/Å2. This dose range was sufficient to determine the EGFR locations with nanometer resolution and to distinguish between monomers and dimers. Various different forms of radiation damage became visible at higher doses, including severe dislocation, and the dissolution of labels.

  2. Precession electron diffraction in scanning transmission electron microscopy: phase, orientation and strain mapping at the nanometer scale

    NASA Astrophysics Data System (ADS)

    Sharp, T. G.

    2015-12-01

    Precession electron diffraction is a technique used in scanning transmission electron microscopy (STEM) to collect electron diffraction patterns while precessing the beam in a cone around the optic axis of the microscope. Electrons are strongly scattered by matter, resulting in dynamical diffraction effects and complex intensity distributions. Precession diffraction produces patterns that are nearly kinematical and lack the complicated intensity distributions of dynamical scattering. These patterns are readily indexed by computer, which allows for the structural characterization of the sample at each pixel. This technique is analogous to electron backscatter diffraction (EBSD), but with higher spatial resolution. Like EBSD, precession diffraction is used to make phase and orientation maps in polycrystalline aggregates and deformed crystals. The technique also provides quantitative strain mapping at the nanometer scale for characterization of defects and coherent interfaces. This technique is especially useful for characterizing nano-scale intergrowths that are produced in high-pressure experiments and in naturally shocked samples. We are using this technique on our aberration corrects JEOL ARM200F STEM. Examples of experimentally and naturally transformed olivine will be presented.

  3. Low Resolution Picture Transmission (LRPT) Demonstration System. Phase II; 1.0

    NASA Technical Reports Server (NTRS)

    Fong, Wai; Yeh, Pen-Shu; Duran, Steve; Sank, Victor; Nyugen, Xuan; Xia, Wei; Day, John H. (Technical Monitor)

    2002-01-01

    Low-Resolution Picture Transmission (LRPT) is a proposed standard for direct broadcast transmission of satellite weather images. This standard is a joint effort by the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) and NOAA. As a digital transmission scheme, its purpose is to replace the current analog Automatic Picture Transmission (APT) system for use in the Meteorological Operational (METOP) satellites. GSFC has been tasked to build an LRPT Demonstration System (LDS). Its main objective is to develop or demonstrate the feasibility of a low-cost receiver utilizing a PC as the primary processing component and determine the performance of the protocol in the simulated Radio Frequency (RF) environment. The approach would consist of two phases.

  4. Interfacing Microfluidics with Negative Stain Transmission Electron Microscopy

    PubMed Central

    Mukhitov, Nikita; Spear, John M.; Stagg, Scott M.; Roper, Michael G.

    2016-01-01

    A microfluidic platform is presented for preparing negatively stained grids for use in transmission electron microscopy (EM). The microfluidic device is composed of glass etched with readily fabricated features that facilitate the extraction of the grid post-staining and maintains the integrity of the sample. Utilization of this device simultaneously reduced environmental contamination on the grids and improved the homogeneity of the heavy metal stain needed to enhance visualization of biological specimens as compared to conventionally prepared EM grids. This easy-to-use EM grid preparation device provides the basis for future developments of systems with more integrated features, which will allow for high throughput and dynamic structural biology studies. PMID:26642355

  5. A Transmission Electron Microscope Study of Experimentally Shocked Pregraphitic Carbon

    NASA Technical Reports Server (NTRS)

    Rietmeijer, Frans J. M.

    1995-01-01

    A transmission electron microscope study of experimental shock metamorphism in natural pre-graphitic carbon simulates the response of the most common natural carbons to increased shock pressure. The d-spacings of this carbon are insensitive to the shock pressure and have no apparent diagnostic value, but progressive comminution occurs in response to increased shock pressure up to 59.6 GPa. The function, P = 869.1 x (size(sub minimum )(exp -0.83), describes the relationship between the minimum root-mean-square subgrain size (nm) and shock pressure (GPa). While a subgrain texture of natural pregraphitic carbons carries little information when pre-shock textures are unknown, this texture may go unnoticed as a shock metamorphic feature.

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

    PubMed

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

    2016-06-01

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

  7. Transmission electron microscope cells for use with liquid samples

    DOEpatents

    Khalid, Waqas; Alivisatos, Paul A.; Zettl, Alexander K.

    2016-08-09

    This disclosure provides systems, methods, and devices related to transmission electron microscopy cells for use with liquids. In one aspect a device includes a substrate, a first graphene layer, and a second graphene layer. The substrate has a first surface and a second surface. The first surface defines a first channel, a second channel, and an outlet channel. The first channel and the second channel are joined to the outlet channel. The outlet channel defines a viewport region forming a though hole in the substrate. The first graphene layer overlays the first surface of the substrate, including an interior area of the first channel, the second channel, and the outlet channel. The second graphene layer overlays the first surface of the substrate, including open regions defined by the first channel, the second channel, and the outlet channel.

  8. Temperature Calibration for In Situ Environmental Transmission Electron Microscopy Experiments

    PubMed Central

    Winterstein, JP; Lin, PA; Sharma, R

    2016-01-01

    In situ environmental transmission electron microscopy (ETEM) experiments require specimen heating holders to study material behavior in gaseous environments at elevated temperatures. In order to extract meaningful kinetic parameters, such as activation energies, it is essential to have a direct and accurate measurement of local sample temperature. This is particularly important if the sample temperature might fluctuate, for example when room temperature gases are introduced to the sample area. Using selected-area diffraction (SAD) in an ETEM, the lattice parameter of Ag nanoparticles was measured as a function of the temperature and pressure of hydrogen gas to provide a calibration of the local sample temperature. SAD permits measurement of temperature to an accuracy of ± 30 °C using Ag lattice expansion. Gas introduction can cause sample cooling of several hundred degrees celsius for gas pressures achievable in the ETEM. PMID:26441334

  9. Transmission electron microscope sample holder with optical features

    DOEpatents

    Milas, Mirko [Port Jefferson, NY; Zhu, Yimei [Stony Brook, NY; Rameau, Jonathan David [Coram, NY

    2012-03-27

    A sample holder for holding a sample to be observed for research purposes, particularly in a transmission electron microscope (TEM), generally includes an external alignment part for directing a light beam in a predetermined beam direction, a sample holder body in optical communication with the external alignment part and a sample support member disposed at a distal end of the sample holder body opposite the external alignment part for holding a sample to be analyzed. The sample holder body defines an internal conduit for the light beam and the sample support member includes a light beam positioner for directing the light beam between the sample holder body and the sample held by the sample support member.

  10. Simultaneous orientation and thickness mapping in transmission electron microscopy

    DOE PAGES

    Tyutyunnikov, Dmitry; Özdöl, V. Burak; Koch, Christoph T.

    2014-12-04

    In this paper we introduce an approach for simultaneous thickness and orientation mapping of crystalline samples by means of transmission electron microscopy. We show that local thickness and orientation values can be extracted from experimental dark-field (DF) image data acquired at different specimen tilts. The method has been implemented to automatically acquire the necessary data and then map thickness and crystal orientation for a given region of interest. We have applied this technique to a specimen prepared from a commercial semiconductor device, containing multiple 22 nm technology transistor structures. The performance and limitations of our method are discussed and comparedmore » to those of other techniques available.« less

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

    PubMed

    Koeck, Philip J B

    2016-02-01

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

  12. Dynamics of a nanodroplet under a transmission electron microscope

    SciTech Connect

    Leong, Fong Yew; Mirsaidov, Utkur M.; Matsudaira, Paul; Mahadevan, L.

    2014-01-15

    We investigate the cyclical stick-slip motion of water nanodroplets on a hydrophilic substrate viewed with and stimulated by a transmission electron microscope. Using a continuum long wave theory, we show how the electrostatic stress imposed by non-uniform charge distribution causes a pinned convex drop to deform into a toroidal shape, with the shape characterized by the competition between the electrostatic stress and the surface tension of the drop, as well as the charge density distribution which follows a Poisson equation. A horizontal gradient in the charge density creates a lateral driving force, which when sufficiently large, overcomes the pinning induced by surface heterogeneities in the substrate disjoining pressure, causing the drop to slide on the substrate via a cyclical stick-slip motion. Our model predicts step-like dynamics in drop displacement and surface area jumps, qualitatively consistent with experimental observations.

  13. Detector non-uniformity in scanning transmission electron microscopy.

    PubMed

    Findlay, S D; LeBeau, J M

    2013-01-01

    A non-uniform response across scanning transmission electron microscope annular detectors has been found experimentally, but is seldom incorporated into simulations. Through case study simulations, we establish the nature and scale of the discrepancies which may arise from failing to account for detector non-uniformity. If standard detectors are used at long camera lengths such that the detector is within or near to the bright field region, we find errors in contrast of the order of 10%, sufficiently small for qualitative work but non-trivial as experiments become more quantitative. In cases where the detector has been characterized in advance, we discuss the detector response normalization and how it may be incorporated in simulations.

  14. Resolution of Transverse Electron Beam Measurements using Optical Transition Radiation

    SciTech Connect

    Ischebeck, Rasmus; Decker, Franz-Josef; Hogan, Mark; Iverson, Richard H.; Krejcik, Patrick; Lincoln, Melissa; Siemann, Robert H.; Walz, Dieter; Clayton, Chris E.; Huang, Chengkun; Lu, Wei; Deng, Suzhi; Oz, Erdem; /Southern California U.

    2005-06-22

    In the plasma wakefield acceleration experiment E-167, optical transition radiation is used to measure the transverse profile of the electron bunches before and after the plasma acceleration. The distribution of the electric field from a single electron does not give a point-like distribution on the detector, but has a certain extension. Additionally, the resolution of the imaging system is affected by aberrations. The transverse profile of the bunch is thus convolved with a point spread function (PSF). Algorithms that deconvolve the image can help to improve the resolution. Imaged test patterns are used to determine the modulation transfer function of the lens. From this, the PSF can be reconstructed. The Lucy-Richardson algorithm is used to deconvolute this PSF from test images.

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

    SciTech Connect

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

    2004-12-01

    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.

  16. Detection of pharmaceutical crystals in polymer particles by transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Ricarte, Ralm; Hillmyer, Marc; Lodge, Timothy

    2015-03-01

    The use of solid dispersions, blends of an active pharmaceutical ingredient (API) and a polymer excipient, may significantly enhance the dissolution performance of a poorly water soluble drug. However, the polymer's role in inhibiting API crystallization within the solid dispersion is not well understood. One of the main challenges in elucidating this mechanism is the difficulty of detecting small amounts of API crystals (less than 5 volume percent) within the polymer matrix. In this work, we explore the use of transmission electron microscopy (TEM) to characterize the crystallinity of griseofulvin (GF) in hydroxypropyl methylcellulose acetate succinate (HPMCAS) solid dispersions. Using both real-space images and electron diffraction patterns from TEM, GF crystals in the HPMCAS matrix were unambiguously identified with nanometer resolution and with a crystal detection sensitivity superior to both wide-angle X-ray scattering and differential scanning calorimetry. TEM shows great potential for characterizing even trace API crystallinity in solid polymeric dispersions.

  17. Cellulose Nanocrystals as Chiral Inducers: Enantioselective Catalysis and Transmission Electron Microscopy 3D Characterization.

    PubMed

    Kaushik, Madhu; Basu, Kaustuv; Benoit, Charles; Cirtiu, Ciprian M; Vali, Hojatollah; Moores, Audrey

    2015-05-20

    Cellulose nanocrystals (CNCs), derived from cellulose, provide us with an opportunity to devise more sustainable solutions to current technological challenges. Enantioselective catalysis, especially heterogeneous, is the preferred method for the synthesis of pure chiral molecules in the fine chemical industries. Cellulose has been long sought as a chiral inducer in enantioselective catalysis. We report herein an unprecedentedly high enantiomeric excess (ee) for Pd patches deposited onto CNCs used as catalysts for the hydrogenation of prochiral ketones in water at room temperature and 4 bar H2. Our system, where CNCs acted as support and sole chiral source, achieved an ee of 65% with 100% conversions. Cryo-electron microscopy, high-resolution transmission electron microscopy, and tomography were used for the first time to study the 3D structure of a metal functionalized CNC hybrid. It established the presence of sub-nanometer-thick Pd patches at the surface of CNCs and provided insight into the chiral induction mechanism.

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

    PubMed

    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.

  19. Robust image alignment for cryogenic transmission electron microscopy.

    PubMed

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

    2016-12-27

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

  20. Microstructure of highly strained BiFeO{sub 3} thin films: Transmission electron microscopy and electron-energy loss spectroscopy studies

    SciTech Connect

    Heon Kim, Young; Bhatnagar, Akash; Pippel, Eckhard; Hesse, Dietrich; Alexe, Marin

    2014-01-28

    Microstructure and electronic structure of highly strained bismuth ferrite (BiFeO{sub 3}) thin films grown on lanthanum aluminate substrates are studied using high-resolution transmission and scanning transmission electron microscopies and electron energy loss spectroscopy (EELS). Monoclinic and tetragonal phases were observed in films grown at different temperatures, and a mix of both phases was detected in a film grown at intermediate temperature. In this film, a smooth transition of the microstructure was found between the monoclinic and the tetragonal phases. A considerable increase in the c-axis parameters was observed in both phases compared with the rhombohedral bulk phase. The off-center displacement of iron (Fe) ions was increased in the monoclinic phase as compared with the tetragonal phase. EEL spectra show different electronic structures in the monoclinic and the tetragonal phases. These experimental observations are well consistent with the results of theoretical first-principle calculations performed.

  1. Microstructure of highly strained BiFeO3 thin films: Transmission electron microscopy and electron-energy loss spectroscopy studies

    NASA Astrophysics Data System (ADS)

    Heon Kim, Young; Bhatnagar, Akash; Pippel, Eckhard; Alexe, Marin; Hesse, Dietrich

    2014-01-01

    Microstructure and electronic structure of highly strained bismuth ferrite (BiFeO3) thin films grown on lanthanum aluminate substrates are studied using high-resolution transmission and scanning transmission electron microscopies and electron energy loss spectroscopy (EELS). Monoclinic and tetragonal phases were observed in films grown at different temperatures, and a mix of both phases was detected in a film grown at intermediate temperature. In this film, a smooth transition of the microstructure was found between the monoclinic and the tetragonal phases. A considerable increase in the c-axis parameters was observed in both phases compared with the rhombohedral bulk phase. The off-center displacement of iron (Fe) ions was increased in the monoclinic phase as compared with the tetragonal phase. EEL spectra show different electronic structures in the monoclinic and the tetragonal phases. These experimental observations are well consistent with the results of theoretical first-principle calculations performed.

  2. High-Resolution Electron Energy-Loss Spectroscopy (HREELS) Using a Monochromated TEM/STEM

    NASA Technical Reports Server (NTRS)

    Sai, Z. R.; Bradley, J. P.; Erni, R.; Browning, N.

    2005-01-01

    A 200 keV FEI TF20 XT monochromated (scanning) transmission electron microscope funded by NASA's SRLIDAP program is undergoing installation at Lawrence Livermore National Laboratory. Instrument specifications in STEM mode are Cs =1.0 mm, Cc =1.2 mm, image resolution =0.18 nm, and in TEM mode Cs =1.3 mm, Cc =1.3 mm, information limit =0.14 nm. Key features of the instrument are a voltage-stabilized high tension (HT) supply, a monochromator, a high-resolution electron energy-loss spectrometer/energy filter, a high-resolution annular darkfield detector, and a solid-state x-ray energy-dispersive spectrometer. The high-tension tank contains additional sections for 60Hz and high frequency filtering, resulting in an operating voltage of 200 kV plus or minus 0.005V, a greater than 10-fold improvement over earlier systems. The monochromator is a single Wien filter design. The energy filter is a Gatan model 866 Tridiem-ERS high resolution GIF spec d for less than or equal to 0.15 eV energy resolution with 29 pA of current in a 2 nm diameter probe. 0.13 eV has already been achieved during early installation. The x-ray detector (EDAX/Genesis 4000) has a take-off angle of 20 degrees, an active area of 30 square millimeters, and a solid angle of 0.3 steradians. The higher solid angle is possible because the objective pole-piece allows the detector to be positioned as close as 9.47 mm from the specimen. The voltage-stabilized HT supply, monochromator and GIF enable high-resolution electron energy-loss spectroscopy (HREELS) with energy resolution comparable to synchrotron XANES, but with approximately 100X better spatial resolution. The region between 0 and 100 eV is called the low-loss or valence electron energy-loss spectroscopy (VEELS) region where features due to collective plasma oscillations and single electron transitions of valence electrons are observed. Most of the low-loss VEELS features we are detecting are being observed for the first time in IDPs. A major focus of

  3. Imaging flux vortices in type II superconductors with a commercial transmission electron microscope.

    PubMed

    Loudon, J C; Midgley, P A

    2009-05-01

    Flux vortices in superconductors can be imaged using transmission electron microscopy because the electron beam is deflected by the magnetic flux associated with the vortices. This technique has a better spatial and temporal resolution than many other imaging techniques and is sensitive to the magnetic flux density within each vortex, not simply the fields at the sample surface. Despite these advantages, only two groups have successfully employed the technique using specially adapted instruments. Here we demonstrate that vortices can be imaged with a modern, commercial transmission electron microscope operating at 300kV equipped with a field emission gun, Lorentz lens and a liquid helium cooled sample holder. We introduce superconductivity for non-specialists and discuss techniques for simulating and optimising images of flux vortices. Sample preparation is discussed in detail as the main difficulty with the technique is the requirement for samples with very large (>10microm), flat areas so that the image is not dominated by diffraction contrast. We have imaged vortices in superconducting Bi(2)Sr(2)CaCu(2)O(8-delta) and use correlation functions to investigate the ordered arrangements they adopt as a function of applied magnetic field.

  4. Atomic-scale imaging and spectroscopy for in situ liquid scanning transmission electron microscopy.

    PubMed

    Jungjohann, Katherine L; Evans, James E; Aguiar, Jeffery A; Arslan, Ilke; Browning, Nigel D

    2012-06-01

    Observation of growth, synthesis, dynamics, and electrochemical reactions in the liquid state is an important yet largely unstudied aspect of nanotechnology. The only techniques that can potentially provide the insights necessary to advance our understanding of these mechanisms is simultaneous atomic-scale imaging and quantitative chemical analysis (through spectroscopy) under environmental conditions in the transmission electron microscope. In this study we describe the experimental and technical conditions necessary to obtain electron energy loss (EEL) spectra from a nanoparticle in colloidal suspension using aberration-corrected scanning transmission electron microscopy (STEM) combined with the environmental liquid stage. At a fluid path length below 400 nm, atomic resolution images can be obtained and simultaneous compositional analysis can be achieved. We show that EEL spectroscopy can be used to quantify the total fluid path length around the nanoparticle and demonstrate that characteristic core-loss signals from the suspended nanoparticles can be resolved and analyzed to provide information on the local interfacial chemistry with the surrounding environment. The combined approach using aberration-corrected STEM and EEL spectra with the in situ fluid stage demonstrates a plenary platform for detailed investigations of solution-based catalysis.

  5. Atomic-Scale Imaging and Spectroscopy for In Situ Liquid Scanning Transmission Electron Microscopy

    SciTech Connect

    Jungjohann, K. L.; Evans, James E.; Aguiar, Jeff; Arslan, Ilke; Browning, Nigel D.

    2012-06-04

    Observation of growth, synthesis, dynamics and electrochemical reactions in the liquid state is an important yet largely unstudied aspect of nanotechnology. The only techniques that can potentially provide the insights necessary to advance our understanding of these mechanisms is simultaneous atomic-scale imaging and quantitative chemical analysis (through spectroscopy) under environmental conditions in the transmission electron microscope (TEM). In this study we describe the experimental and technical conditions necessary to obtain electron energy loss (EEL) spectra from a nanoparticle in colloidal suspension using aberration corrected scanning transmission electron microscopy (STEM) combined with the environmental liquid stage. At a fluid path length below 400 nm, atomic resolution images can be obtained and simultaneous compositional analysis can be achieved. We show that EEL spectroscopy can be used to quantify the total fluid path length around the nanoparticle, and demonstrate characteristic core-loss signals from the suspended nanoparticles can be resolved and analyzed to provide information on the local interfacial chemistry with the surrounding environment. The combined approach using aberration corrected STEM and EEL spectra with the in situ fluid stage demonstrates a plenary platform for detailed investigations of solution based catalysis and biological research.

  6. Studying Dynamic Processes of Nano-sized Objects in Liquid using Scanning Transmission Electron Microscopy.

    PubMed

    Hermannsdörfer, Justus; de Jonge, Niels

    2017-02-05

    Samples fully embedded in liquid can be studied at a nanoscale spatial resolution with Scanning Transmission Electron Microscopy (STEM) using a microfluidic chamber assembled in the specimen holder for Transmission Electron Microscopy (TEM) and STEM. The microfluidic system consists of two silicon microchips supporting thin Silicon Nitride (SiN) membrane windows. This article describes the basic steps of sample loading and data acquisition. Most important of all is to ensure that the liquid compartment is correctly assembled, thus providing a thin liquid layer and a vacuum seal. This protocol also includes a number of tests necessary to perform during sample loading in order to ensure correct assembly. Once the sample is loaded in the electron microscope, the liquid thickness needs to be measured. Incorrect assembly may result in a too-thick liquid, while a too-thin liquid may indicate the absence of liquid, such as when a bubble is formed. Finally, the protocol explains how images are taken and how dynamic processes can be studied. A sample containing AuNPs is imaged both in pure water and in saline.

  7. Transmission Electron Diffraction Studies of Xenon Adsorbed on Graphite.

    NASA Astrophysics Data System (ADS)

    Faisal, A. Q. D.

    1987-09-01

    Available from UMI in association with The British Library. Adsorption studies of xenon on graphite were performed using the Hitachi HU-11B Transmission Electron Microscope (TEM). It has been used as a Transmission High Energy Electron Diffraction (THEED) camera. This has been modified to include an Ultra High Vacuum (UHV) environmental chamber. This chamber was isolated from the microscope vacuum by two 400 μm diameter differentially pumped apertures. Pressures of {~}10 ^{-6} torr and {~ }10^{-9} torr were achieved inside the microscope column and the environmental chamber respectively. The chamber was fitted with a new sample holder designed with double "O" rings. The sample was cooled with liquid helium. Previous THEED experiments by Venables et al and Schabes-Retchkiman and Venables revealed the presence of a 2D-solid incommensurate (I)-commensurate (C) phase transition as the temperature is lowered. These results were confirmed and extended in the present work. Hong et al have recently interpreted their X-ray diffraction experiments as showing an incommensurate-striped domain phase transition at {~}65rm K. No evidence was found for the existence of a striped domain structure on any part of the xenon phase diagram studied. Experiments of xenon adsorbed on the basal plane (0001) of graphite were carried out at pressures from {~}1.5 times 10^{-5} torr to {~}1.8 times 10^{-8} torr over a temperature range from 55K^.90K. A set of lattice parameter (misfit) measurements were made as a function of temperature at constant pressure with an accuracy of +/-0.1% rather than +/-0.3% previously obtained. The misfit data was fitted to a power law formula, i.e. misfit m = B_{rm o} (rm T - rm T_{rm o})^{rm A} , where A is a constant and equal to 0.8. It was found that B_{rm o} and T_{rm o} are functions of log(P). The data fell into two groups corresponding to two phase transitions. The same power law was used for both sets of data. Two transitions were found, one is I-C and

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

    PubMed

    Nebesarova, Jana; Wandrol, Petr; Vancova, Marie

    2016-01-01

    We present a new method of multiple immunolabeling that is suitable for a broad spectrum of biomedical applications. The general concept is to label both sides of the ultrathin section with the thickness of 70-80 nm with different antibodies conjugated to gold nanoparticles and to distinguish the labeled side by advanced imaging methods with high resolution scanning electron microscopy, such as by correlating images acquired at different energies of primary electrons using different signals. From the Clinical Editor: The use of transmission electron microscopy has become an indispensible tool in the detection of cellular proteins. In this short but interesting article, the authors described their new method of labeling and the identification of four different proteins simultaneously, which represents another advance in imaging technique.

  9. In situ transmission electron microscopy of electron-beam induced damage process in nuclear grade graphite

    NASA Astrophysics Data System (ADS)

    Karthik, C.; Kane, J.; Butt, D. P.; Windes, W. E.; Ubic, R.

    2011-05-01

    Atomic level processes involved in the swelling and crack-closing in nuclear grade graphite under electron irradiation have been observed in real-time using transmission electron microscopy. Noise-filtered lattice images show the formation of vacancy loops, interstitial loops and resulting dislocations with unprecedented clarity. The dislocation dipoles formed via vacancy loops were found to undergo climb resulting in extra basal planes. Concurrent EELS studies showed a reduction in the atomic density because of the breakage of hexagonal carbon rings. The formation of new basal planes via dislocation climb in addition to the bending/breaking of basal planes leads to swelling and closing of micro-cracks.

  10. Nanocuvette: A Functional Ultrathin Liquid Container for Transmission Electron Microscopy.

    PubMed

    Wadell, Carl; Inagaki, Satoshi; Nakamura, Tomiro; Shi, Ji; Nakamura, Yoshio; Sannomiya, Takumi

    2017-02-28

    Advances in TEM techniques have spurred a renewed interest in a wide variety of research fields. A rather recent track within these endeavors is the use of TEM for in situ imaging in liquids. In this article, we show the fabrication of a liquid cell for TEM observations which we call the nanocuvette. The structure consists of a nanohole film sandwiched by carbon films, sealing liquid in the holes. The hole film can be produced using a variety of materials, tailored for the desired application. Since the fabrication is based on self-assembly, it is both cheap and straightforward. Compared to previously reported liquid cells, this structure allows for thinner liquid layers with better controlled cell structures, making it possible to achieve a high resolution even at lower acceleration voltages and electron doses. We demonstrate a resolution corresponding to an information transfer up to ∼2 nm at 100 kV for molecular imaging. Apart from the advantages arising from the thin liquid layer, the nanocuvette also enables the possibility to study liquid-solid interfaces at the side walls of the nanoholes. We illustrate the possibilities of the nanocuvette by studying several model systems: electron beam induced growth dynamics of silver nanoparticles in salt solution, polymer deposition from solution, and imaging of nonstained antibodies in solution. Finally, we show how the inclusion of a plasmonically active gold layer in the nanocuvette structure enables optical confirmation of successful liquid encapsulation prior to TEM studies. The nanocuvette provides an easily fabricated and flexible platform which can help further the understanding of reactions, processes, and conformation of molecules and atoms in liquid environments.

  11. Correlative super-resolution fluorescence and electron microscopy of the nuclear pore complex with molecular resolution.

    PubMed

    Löschberger, Anna; Franke, Christian; Krohne, Georg; van de Linde, Sebastian; Sauer, Markus

    2014-10-15

    Here, we combine super-resolution fluorescence localization microscopy with scanning electron microscopy to map the position of proteins of nuclear pore complexes in isolated Xenopus laevis oocyte nuclear envelopes with molecular resolution in both imaging modes. We use the periodic molecular structure of the nuclear pore complex to superimpose direct stochastic optical reconstruction microscopy images with a precision of <20 nm on electron micrographs. The correlative images demonstrate quantitative molecular labeling and localization of nuclear pore complex proteins by standard immunocytochemistry with primary and secondary antibodies and reveal that the nuclear pore complex is composed of eight gp210 (also known as NUP210) protein homodimers. In addition, we find subpopulations of nuclear pore complexes with ninefold symmetry, which are found occasionally among the more typical eightfold symmetrical structures.

  12. Transmission Electron Microscopy of Magnetite Plaquettes in Orgueil

    NASA Technical Reports Server (NTRS)

    Chan, Q. H. S.; Han, J.; Zolensky, M.

    2016-01-01

    Magnetite sometimes takes the form of a plaquette - barrel-shaped stack of magnetite disks - in carbonaceous chondrites (CC) that show evidence of aqueous alteration. The asymmetric nature of the plaquettes caused Pizzarello and Groy to propose magnetite plaquettes as a naturally asymmetric mineral that can indroduce symmetry-breaking in organic molecules. Our previous synchrotron X-ray computed microtomography (SXRCT) and electron backscatter diffraction (EBSD) analyses of the magnetite plaquettes in fifteen CCs indicate that magnetite plaquettes are composed of nearly parallel discs, and the crystallographic orientations of the discs change around a rotational axis normal to the discs surfaces. In order to further investigate the nanostructures of magnetite plaquettes, we made two focused ion beam (FIB) sections of nine magnetite plaquettes from a thin section of CI Orgueil for transmission electron microscope (TEM) analysis. The X-ray spectrum imaging shows that the magnetite discs are purely iron oxide Fe3O4 (42.9 at% Fe and 57.1 at% O), which suggest that the plaquettes are of aqueous origin as it is difficult to form pure magnetite as a nebular condensate. The selected area electron diffraction (SAED) patterns acquired across the plaquettes show that the magnetite discs are single crystals. SEM and EBSD analyses suggest that the planar surfaces of the magnetite discs belong to the {100} planes of the cubic inverse spinel structure, which are supported by our TEM observations. Kerridge et al. suggested that the epitaxial relationship between magnetite plaquette and carbonate determines the magnetite face. However, according to our TEM observation, the association of magnetite with porous networks of phyllosilicate indicates that the epitaxial relationship with carbonate is not essential to the formation of magnetite plaquettes. It was difficult to determine the preferred rotational orientation of the plaquettes due to the symmetry of the cubic structure

  13. High resolution X-ray CT for advanced electronics packaging

    NASA Astrophysics Data System (ADS)

    Oppermann, M.; Zerna, T.

    2017-02-01

    Advanced electronics packaging is a challenge for non-destructive Testing (NDT). More, smaller and mostly hidden interconnects dominate modern electronics components and systems. To solve the demands of customers to get products with a high functionality by low volume, weight and price (e.g. mobile phones, personal medical monitoring systems) often the designers use System-in-Package solutions (SiP). The non-destructive testing of such devices is a big challenge. So our paper will impart fundamentals and applications for non-destructive evaluation of inner structures of electronics packaging for quality assurance and reliability investigations with a focus on X-ray methods, especially on high resolution X-ray computed tomography (CT).

  14. Magnetic dynamics studied by high-resolution electron spectroscopy and time-resolved electron microscopy

    NASA Astrophysics Data System (ADS)

    Jayaraman, Rajeswari

    Future information technology requires an increased magnetically encoded data density and novel electromagnetic modes of data transfer. While to date magnetic properties are observed and characterized mostly statically, the need emerges to monitor and capture their fast dynamics. In this talk, I will focus on the spin dynamics i.e. spin wave excitations and the dynamics of a new topological distribution of spins termed ``skyrmions''. Wave packets of spin waves offer the unique capability to transport a quantum bit, the spin, without the transport of charge or mass. Here, large wave-vector spin waves are of particular interest as they admit spin localization within a few nanometers. By using our recently developed electron energy loss spectrometer, we could study such spin waves in ultrathin films with an unprecedented energy resolution of 4 meV. By virtue of the finite penetration depth of low energy electrons, spin waves localized at interfaces between a substrate and a thin capping layer can be been studied yielding information about the exchange coupling between atoms at the interface. The quantization of spin waves with wave vectors perpendicular to the film gives rise to standing modes to which EELS has likewise access. Such studies when carried out as function of the film thickness again yield information on the layer dependence of the exchange coupling. Magnetic skyrmions are promising candidates as information carriers in logic or storage devices. Currently, little is known about the influence of disorder, defects, or external stimuli on the spatial distribution and temporal evolution of the skyrmion lattice. In this talk, I will describe the dynamical role of disorder in a large and flat thin film of Cu2OSeO3, exhibiting a skyrmion phase in an insulating material. We image up to 70,000 skyrmions by means of cryo-Lorentz Transmission Electron Microscopy as a function of the applied magnetic field. In the skyrmion phase, dislocations are shown to cause the

  15. Measurement of vibrational spectrum of liquid using monochromated scanning transmission electron microscopy-electron energy loss spectroscopy.

    PubMed

    Miyata, Tomohiro; Fukuyama, Mao; Hibara, Akihide; Okunishi, Eiji; Mukai, Masaki; Mizoguchi, Teruyasu

    2014-10-01

    Investigations on the dynamic behavior of molecules in liquids at high spatial resolution are greatly desired because localized regions, such as solid-liquid interfaces or sites of reacting molecules, have assumed increasing importance with respect to improving material performance. In application to liquids, electron energy loss spectroscopy (EELS) observed with transmission electron microscopy (TEM) is a promising analytical technique with the appropriate resolutions. In this study, we obtained EELS spectra from an ionic liquid, 1-ethyl-3-methylimidazolium bis (trifluoromethyl-sulfonyl) imide (C2mim-TFSI), chosen as the sampled liquid, using monochromated scanning TEM (STEM). The molecular vibrational spectrum and the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap of the liquid were investigated. The HOMO-LUMO gap measurement coincided with that obtained from the ultraviolet-visible spectrum. A shoulder in the spectrum observed ∼0.4 eV is believed to originate from the molecular vibration. From a separately performed infrared observation and first-principles calculations, we found that this shoulder coincided with the vibrational peak attributed to the C-H stretching vibration of the [C2mim(+)] cation. This study demonstrates that a vibrational peak for a liquid can be observed using monochromated STEM-EELS, and leads one to expect observations of chemical reactions or aids in the analysis of the dynamic behavior of molecules in liquid.

  16. Nanoscale imaging of whole cells using a liquid enclosure and a scanning transmission electron microscope.

    PubMed

    Peckys, Diana B; Veith, Gabriel M; Joy, David C; de Jonge, Niels

    2009-12-14

    Nanoscale imaging techniques are needed to investigate cellular function at the level of individual proteins and to study the interaction of nanomaterials with biological systems. We imaged whole fixed cells in liquid state with a scanning transmission electron microscope (STEM) using a micrometer-sized liquid enclosure with electron transparent windows providing a wet specimen environment. Wet-STEM images were obtained of fixed E. coli bacteria labeled with gold nanoparticles attached to surface membrane proteins. Mammalian cells (COS7) were incubated with gold-tagged epidermal growth factor and fixed. STEM imaging of these cells resulted in a resolution of 3 nm for the gold nanoparticles. The wet-STEM method has several advantages over conventional imaging techniques. Most important is the capability to image whole fixed cells in a wet environment with nanometer resolution, which can be used, e.g., to map individual protein distributions in/on whole cells. The sample preparation is compatible with that used for fluorescent microscopy on fixed cells for experiments involving nanoparticles. Thirdly, the system is rather simple and involves only minimal new equipment in an electron microscopy (EM) laboratory.

  17. Quantifying Transient States in Materials with the Dynamic Transmission Electron Microscope

    SciTech Connect

    Campbell, G; LaGrange, T; Kim, J; Reed, B; Browning, N

    2009-09-21

    The Dynamic Transmission Electron Microscope (DTEM) offers a means of capturing rapid evolution in a specimen through in-situ microscopy experiments by allowing 15 ns electron micrograph exposure times. The rapid exposure time is enabled by creating a burst of electrons at the emitter by ultraviolet pulsed laser illumination. This burst arrives a specified time after a second laser initiates the specimen reaction. The timing of the two Q-switched lasers is controlled by high-speed pulse generators with a timing error much less than the pulse duration. Both diffraction and imaging experiments can be performed, just as in a conventional TEM. The brightness of the emitter and the total current control the spatial and temporal resolutions. We have demonstrated 7 nm spatial resolution in single 15 ns pulsed images. These single-pulse imaging experiments have been used to study martensitic transformations, nucleation and crystallization of an amorphous metal, and rapid chemical reactions. Measurements have been performed on these systems that are possible by no other experimental approaches currently available.

  18. Nanoscale imaging of whole cells using a liquid enclosure and a scanning transmission electron microscopy

    SciTech Connect

    De Jonge, Niels; Peckys, Diana B; Veith, Gabriel M; Joy, David Charles

    2009-01-01

    Nanoscale imaging techniques are needed to investigate cellular function at the level of individual proteins and to study the interaction of nanomaterials with biological systems. We imaged whole fixed cells in liquid state with a scanning transmission electron microscope (STEM) using a micrometer-sized liquid enclosure with electron transparent windows providing a wet specimen environment. Wet-STEM images were obtained of fixed E. coli bacteria labeled with gold nanoparticles attached to surface membrane proteins. Mammalian cells (COS7) were incubated with gold-tagged epidermal growth factor and fixed. STEM imaging of these cells resulted in a resolution of 3 nm for the gold nanoparticles. The wet-STEM method has several advantages over conventional imaging techniques. Most important is the capability to image whole fixed cells in a wet environment with nanometer resolution, which can be used, e.g., to map individual protein distributions in/on whole cells. The sample preparation is compatible with that used for fluorescent microscopy on fixed cells for experiments involving nanoparticles. Thirdly, the system is rather simple and involves only minimal new equipment in an electron microscopy (EM) laboratory.

  19. Characterizations of Preheated and Non-Preheated HY-80 Steel Weldments by Transmission Electron Microscopy.

    DTIC Science & Technology

    1983-09-01

    D- 36 966 CHARACTERIZATIONS OF PREHEATED AND NON-PREHEATED HY-80 i/I • " STEEL NELDMENTS BY TRANSMISSION ELECTRON MICROSCOPY(U) C T T NAVAL...34. NAVAL POSTGRADUATE SCHOOL Monterey, California THESIS CHARACTERIZATIONS OF PREHEATED AND NON-PREHEATED HY-80 STEEL WELDMENTS BY TRANSMISSION ELECTRON...Master’s Thesis; Non-Preheated HY-80 Steel Weldments September 1983 by Transmission Electron Microscopy S. PERFORMING ONG. REPORT NUMBER 7. ATNOR"a S

  20. Direct electron detection yields cryo-EM reconstructions at resolutions beyond ¾ Nyquist frequency

    PubMed Central

    Bammes, Benjamin E.; Rochat, Ryan H.; Jakana, Joanita; Chen, Dong-Hua; Chiu, Wah

    2012-01-01

    One limitation in electron cryo-microscopy (cryo-EM) is the inability to recover high-resolution signal from the image-recording media at the full-resolution limit of the transmission electron microscope. Direct electron detection using CMOS-based sensors for digitally recording images has the potential to alleviate this shortcoming. Here, we report a practical performance evaluation of a Direct Detection Device (DDD) for biological cryo-EM at two different microscope voltages: 200 and 300 kV. Our DDD images of amorphous and graphitized carbon show strong per-pixel contrast with image resolution near the theoretical sampling limit of the data. Single-particle reconstructions of two frozen-hydrated bacteriophages, P22 and ε15, establish that the DDD is capable of recording usable signal for 3-D reconstructions at about 4/5 of the Nyquist frequency, which is a vast improvement over the performance of conventional imaging media. We anticipate the unparalleled performance of this digital recording device will dramatically benefit cryo-EM for routine tomographic and single-particle structural determination of biological specimens. PMID:22285189

  1. Sample thickness determination by scanning transmission electron microscopy at low electron energies.

    PubMed

    Volkenandt, Tobias; Müller, Erich; Gerthsen, Dagmar

    2014-02-01

    Sample thickness is a decisive parameter for any quantification of image information and composition in transmission electron microscopy. In this context, we present a method to determine the local sample thickness by scanning transmission electron microscopy at primary energies below 30 keV. The image intensity is measured with respect to the intensity of the incident electron beam and can be directly compared with Monte Carlo simulations. Screened Rutherford and Mott scattering cross-sections are evaluated with respect to fitting experimental data with simulated image intensities as a function of the atomic number of the sample material and primary electron energy. The presented method is tested for sample materials covering a wide range of atomic numbers Z, that is, fluorenyl hexa-peri-hexabenzocoronene (Z = 3.5), carbon (Z = 6), silicon (Z = 14), gallium nitride (Z = 19), and tungsten (Z = 74). Investigations were conducted for two primary energies (15 and 30 keV) and a sample thickness range between 50 and 400 nm.

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

    PubMed Central

    2011-01-01

    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. PMID:21749679

  3. Multilayer Patterning of High Resolution Intrinsically Stretchable Electronics

    PubMed Central

    Tybrandt, Klas; Stauffer, Flurin; Vörös, Janos

    2016-01-01

    Stretchable electronics can bridge the gap between hard planar electronic circuits and the curved, soft and elastic objects of nature. This has led to applications like conformal displays, electronic skin and soft neuroprosthetics. A remaining challenge, however, is to match the dimensions of the interfaced systems, as all require feature sizes well below 100 μm. Intrinsically stretchable nanocomposites are attractive in this context as the mechanical deformations occur on the nanoscale, although methods for patterning high performance materials have been lacking. Here we address these issues by reporting on a multilayer additive patterning approach for high resolution fabrication of stretchable electronic devices. The method yields highly conductive 30 μm tracks with similar performance to their macroscopic counterparts. Further, we demonstrate a three layer micropatterned stretchable electroluminescent display with pixel sizes down to 70 μm. These presented findings pave the way towards future developments of high definition displays, electronic skins and dense multielectrode arrays. PMID:27157804

  4. In situ transmission electron microscopy experimentation of nanostructured materials

    NASA Astrophysics Data System (ADS)

    Alducin, Diego

    Due to the remarkable mechanical and electrical properties some nanostructured materials possess, it is important to be able to quantitatively characterize how these materials react under different types of stimulus. In situ transmission electron microscopy is a unique technique that allows the user to fully observe and record the crystallographic behavior of such materials undergoing a variety of tests. The crystallographic orientations silver nanowires were mapped in order to understand the structure and facets due to its geometry. Measuring the toughness and yield of the material led us to understand the anisotropic behavior of AgNWs. Depending on whether a load is applied to either a boundary between facets or on a facet will change the mechanical strength of the nanowire. By measuring the resistivity of the this material during deformation has also led us to understand that the intrinsic defects in the crystal structure of nanowires will change the way the material reacts to an electric potential. We have been also able to completely map the crystallographic orientations of very complex geometries of gold nanoparticles and characterize the weak forces involved in the manipulation if these nanoparticles. Finally, the elasticity of MoS2 was tested and found to be exponentially dependent upon the thickness of the nanosheets. However, the resistivity of this material does not seem to be affected by any type of deformation it is subjected to. The complete categorization of how materials interact with external stimulus while comparing the changes observed in its crystal structure is essential to understanding the underlying properties of nanostructured materials, which would not be possible without in situ transmisison electron microscopy experimentation.

  5. Probing electron beam effects with chemoresistive nanosensors during in situ environmental transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Steinhauer, S.; Wang, Z.; Zhou, Z.; Krainer, J.; Köck, A.; Nordlund, K.; Djurabekova, F.; Grammatikopoulos, P.; Sowwan, M.

    2017-02-01

    We report in situ and ex situ fabrication approaches to construct p-type (CuO) and n-type (SnO2) metal oxide nanowire devices for operation inside an environmental transmission electron microscope (TEM). By taking advantage of their chemoresistive properties, the nanowire devices were employed as sensitive probes for detecting reactive species induced by the interactions of high-energy electrons with surrounding gas molecules, in particular, for the case of O2 gas pressures up to 20 mbar. In order to rationalize our experimental findings, a computational model based on the particle-in-cell method was implemented to calculate the spatial distributions of scattered electrons and ionized oxygen species in the environmental TEM. Our approach enables the a priori identification and qualitative measurement of undesirable beam effects, paving the way for future developments related to their mitigation.

  6. Rapid diagnosis of plant virus diseases by transmission electron microscopy.

    PubMed

    Zechmann, Bernd; Zellnig, Günther

    2009-12-01

    A clear and rapid diagnosis of plant virus diseases is of great importance for agriculture and scientific experiments in plant phytopathology. Even though negative staining and transmission electron microscopy (TEM) are often used for detection and identification of viral particles and provide rapid and reliable results, it is necessary to examine ultrastructural changes induced by viruses for clear identification of the disease. With conventional sample preparation for TEM it can take several days to obtain ultrastructural results and it is therefore not suitable for rapid diagnosis of virus diseases of plants. The use of microwave irradiation can reduce the time for sample preparation for TEM investigations. Two model virus-plant systems [Nicotiana tabacum plants infected with Tobacco mosaic virus (TMV), Cucurbita pepo plants infected with Zucchini yellow mosaic virus (ZYMV)] demonstrate that it is possible to diagnose ultrastructural alterations induced by viruses in less than half a day by using microwave irradiation for preparation of samples. Negative staining of the sap of plants infected with TMV and ZYMV and the examination of ultrastructure and size were also carried out during sample preparation thus permitting diagnosis of the viral agent by TEM in a few hours. These methods will contribute towards a rapid and clear identification of virus diseases of plants and will be useful for diagnostic purposes in agriculture and in plant phytopathology.

  7. Characterization of paired helical filaments by scanning transmission electron microscopy.

    PubMed

    Ksiezak-Reding, Hanna; Wall, Joseph S

    2005-07-01

    Paired helical filaments (PHFs) are abnormal twisted filaments composed of hyperphosphorylated tau protein. They are found in Alzheimer's disease and other neurodegenerative disorders designated as tauopathies. They are a major component of intracellular inclusions known as neurofibrillary tangles (NFTs). The objective of this review is to summarize various structural studies of PHFs in which using scanning transmission electron microscopy (STEM) has been particularly informative. STEM provides shape and mass per unit length measurements important for studying ultrastructural aspects of filaments. These include quantitative comparisons between dispersed and aggregated populations of PHFs as well as comparative studies of PHFs in Alzheimer's disease and other neurodegenerative disorders. Other approaches are also discussed if relevant or complementary to studies using STEM, e.g., application of a novel staining reagent, Nanovan. Our understanding of the PHF structure and the development of PHFs into NFTs is presented from a historical perspective. Others goals are to describe the biochemical and ultrastructural complexity of authentic PHFs, to assess similarities between authentic and synthetic PHFs, and to discuss recent advances in PHF modeling.

  8. Low Voltage Transmission Electron Microscopy in Cell Biology.

    PubMed

    Bendayan, Moise; Paransky, Eugene

    2015-07-01

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

  9. High-resolution AMLCD for the electronic library system

    NASA Astrophysics Data System (ADS)

    Martin, Russel A.; Middo, Kathy; Turner, William D.; Lewis, Alan; Thompson, Malcolm J.; Silverstein, Louis D.

    1994-06-01

    The Electronic Library System (ELS), is a proposed data resource for the cockpit which can provide the aircrew with a vast array of technical information on their aircraft and flight plan. This information includes, but is not limited to, approach plates, Jeppeson Charts, and aircraft technical manuals. Most of these data are appropriate for digitization at high resolution (300 spi). Xerox Corporation has developed a flat panel active matrix liquid crystal display, AMLCD, that is an excellent match to the ELS, due to its innovative and aggressive design.

  10. High resolution electron microscopy study of amorphous calcium phosphate

    NASA Astrophysics Data System (ADS)

    Brès, E. F.; Moebus, G.; Kleebe, H.-J.; Pourroy, G.; Werkmann, J.; Ehret, G.

    1993-03-01

    "Amorphous" calcium phosphate (ACP) from human tooth enamel and different synthetic materials has been analysed by high resolution electron microscopy (HREM). All the materials studied showed, in addition to a "truly" amorphous phase, other calcium phosphate phases such as poorly crystalline hydroxyapatite (OHAP), well crystallized OHAP and poorly crystalline CaO type phase. Such structural heterogeneities have not been observed before in ACP, and are only possible to be detected by HREM as this is the only technique able to analyse nanometre size materials in the real space.

  11. The formation and interpretation of defect images from crystalline materials in a scanning transmission electron microscope.

    PubMed

    Maher, D M; Joy, D C

    1976-06-01

    The technique of scanning transmission electron microscopy (STEM) has been employed usefully in studies of amorphous materials, and the theory of image formation and interpretation in this case has been well developed. Less attention has been given to the practical and theoretical problems associated with the use of STEM for the examination of crystalline materials. In this case the contrast mechanisms are dominated by Bragg diffraction and so they are quite different from those occurring in amorphous substances. In this paper practical techniques for the observation and interpretation of contrast from defects in crystalline materials are discussed. It is shown that whilst images of defects are obtained readily under all typical STEM operating conditions, the form of the image and the information it contains varies with the angle subtended at the specimen by the detector. If this angle is too large significant image modifications relative to the "conventional" transmission electron microscope case may occur and the resolution of the image may degrade. If this angle is too small, then signal to noise considerations make an interpretation of the image difficult. In this paper we indicate how the detector angle may be chosen correctly, and also present techniques for setting up a STEM instrument for imaging a crystalline material containing lattice defects.

  12. A Scanning Transmission Electron Microscopy (STEM) Approach to Analyzing Large Volumes of Tissue to Detect Nanoparticles

    PubMed Central

    Kempen, Paul J.; Thakor, Avnesh S.; Zavaleta, Cristina; Gambhir, Sanjiv S.; Sinclair, Robert

    2013-01-01

    The use of nanoparticles for the diagnosis and treatment of cancer requires the complete characterization of their toxicity, including accurately locating them within biological tissues. Owing to their size, traditional light microscopy techniques are unable to resolve them. Transmission electron microscopy provides the necessary spatial resolution to image individual nanoparticles in tissue but is severely limited by the very small analysis volume, usually on the order of tens of cubic microns. In this work we developed a scanning transmission electron microscopy (STEM) approach to analyze large volumes of tissue for the presence of polyethylene glycol coated Raman-active-silica-gold-nanoparticles (PEG-R-Si-Au-NPs). This approach utilizes the simultaneous bright and dark field imaging capabilities of STEM along with careful control of the image contrast settings to readily identify PEG-R-Si-Au-NPs in mouse liver tissue without the need for additional time consuming analytical characterization. We utilized this technique to analyze 243,000 µm3 of mouse liver tissue for the presence of PEG-R-Si-Au-NPs. Nanoparticles injected into the mice intravenously via the tail-vein accumulated in the liver while those injected intrarectally did not, indicating that they remain in the colon and do not pass through the colon wall into the systemic circulation. PMID:23803218

  13. A scanning transmission electron microscopy approach to analyzing large volumes of tissue to detect nanoparticles.

    PubMed

    Kempen, Paul J; Thakor, Avnesh S; Zavaleta, Cristina; Gambhir, Sanjiv S; Sinclair, Robert

    2013-10-01

    The use of nanoparticles for the diagnosis and treatment of cancer requires the complete characterization of their toxicity, including accurately locating them within biological tissues. Owing to their size, traditional light microscopy techniques are unable to resolve them. Transmission electron microscopy provides the necessary spatial resolution to image individual nanoparticles in tissue, but is severely limited by the very small analysis volume, usually on the order of tens of cubic microns. In this work, we developed a scanning transmission electron microscopy (STEM) approach to analyze large volumes of tissue for the presence of polyethylene glycol-coated Raman-active-silica-gold-nanoparticles (PEG-R-Si-Au-NPs). This approach utilizes the simultaneous bright and dark field imaging capabilities of STEM along with careful control of the image contrast settings to readily identify PEG-R-Si-Au-NPs in mouse liver tissue without the need for additional time-consuming analytical characterization. We utilized this technique to analyze 243,000 mm³ of mouse liver tissue for the presence of PEG-R-Si-Au-NPs. Nanoparticles injected into the mice intravenously via the tail vein accumulated in the liver, whereas those injected intrarectally did not, indicating that they remain in the colon and do not pass through the colon wall into the systemic circulation.

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

    PubMed

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

    2017-05-01

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

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

    PubMed

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

    2017-03-02

    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 (<3eV). In this contribution, high-resolution EELS was used to investigate four materials commonly used in organic photovoltaics (OPVs): poly(3-hexlythiophene) (P3HT), [6,6] phenyl-C61 butyric acid methyl ester (PCBM), copper phthalocyanine (CuPc), and fullerene (C60). 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.

  16. Unravelling surface and interfacial structures of a metal-organic framework by transmission electron microscopy.

    PubMed

    Zhu, Yihan; Ciston, Jim; Zheng, Bin; Miao, Xiaohe; Czarnik, Cory; Pan, Yichang; Sougrat, Rachid; Lai, Zhiping; Hsiung, Chia-En; Yao, Kexin; Pinnau, Ingo; Pan, Ming; Han, Yu

    2017-02-20

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

  17. Rapidly Alternating Transmission Mode Electron Transfer Dissociation and Collisional Activation for the Characterization of Polypeptide Ions

    PubMed Central

    Han, Hongling; Xia, Yu; Yang, Min; McLuckey, Scott A.

    2009-01-01

    Cation transmission/electron transfer reagent anion storage mode electron transfer ion/ion reactions and beam-type collisional activation of the polypeptide ions are performed in rapid succession in the high pressure collision cell (Q2) of a quadrupole/time-of-flight tandem mass spectrometer (QqTOF), where the electron transfer reagent anions are accumulated. Duty cycles for both electron transfer dissociation (ETD) and collision-induced dissociation (CID) experiments are improved relative to ion trapping approaches since there are no discrete ion storage and reaction steps for ETD experiments and no discrete ion storage step and frequency tuning for CID experiments. For this technique, moderately high resolution and mass accuracy are also obtained due to mass analysis via the TOF analyzer. This relatively simple approach has been demonstrated with a triply charged tryptic peptide, a triply charged tryptic phosphopeptide, and a triply charged tryptic N-linked glycopeptide. For the tryptic peptide, the sequence is identified with more certainty than would be available from a single method alone due to the complementary information provided by these two dissociation methods. Because of the complementary information derived from both ETD and CID dissociation methods, peptide sequence and post-translational modification (PTM) sites for the phosphopeptide are identified. This combined ETD and CID approach is particularly useful for characterizing glycopeptides because ETD generates information about both peptide sequence and locations of the glycosylation sites while CID provides information about the glycan structure. PMID:18396915

  18. Microcalorimeter-type energy dispersive X-ray spectrometer for a transmission electron microscope.

    PubMed

    Hara, Toru; Tanaka, Keiichi; Maehata, Keisuke; Mitsuda, Kazuhisa; Yamasaki, Noriko Y; Ohsaki, Mitsuaki; Watanabe, Katsuaki; Yu, Xiuzhen; Ito, Takuji; Yamanaka, Yoshihiro

    2010-01-01

    A new energy dispersive X-ray spectrometer (EDS) with a microcalorimeter detector equipped with a transmission electron microscope (TEM) has been developed for high- accuracy compositional analysis in the nanoscale. A superconducting transition-edge-sensor-type microcalorimeter is applied as the detector. A cryogen-free cooling system, which consists of a mechanical and a dilution refrigerator, is selected to achieve long-term temperature stability. In order to mount these detector and refrigerators on a TEM, the cooling system is specially designed such that these two refrigerators are separated. Also, the detector position and arrangement are carefully designed to avoid adverse affects between the superconductor detector and the TEM lens system. Using the developed EDS system, at present, an energy resolution of 21.92 eV full-width-at-half maximum has been achieved at the Cr K alpha line. This value is about seven times better than that of the current typical commercial Si(Li) detector, which is usually around 140 eV. The developed microcalorimeter EDS system can measure a wide energy range, 1-20 keV, at one time with this high energy resolution that can resolve peaks from most of the elements. Although several further developments will be needed to enable practical use, highly accurate compositional analysis with high energy resolution will be realized by this microcalorimeter EDS system.

  19. Visualizing non-equilibrium lithiation of spinel oxide via in situ transmission electron microscopy.

    PubMed

    He, Kai; Zhang, Sen; Li, Jing; Yu, Xiqian; Meng, Qingping; Zhu, Yizhou; Hu, Enyuan; Sun, Ke; Yun, Hongseok; Yang, Xiao-Qing; Zhu, Yimei; Gan, Hong; Mo, Yifei; Stach, Eric A; Murray, Christopher B; Su, Dong

    2016-05-09

    Spinel transition metal oxides are important electrode materials for lithium-ion batteries, whose lithiation undergoes a two-step reaction, whereby intercalation and conversion occur in a sequential manner. These two reactions are known to have distinct reaction dynamics, but it is unclear how their kinetics affects the overall electrochemical response. Here we explore the lithiation of nanosized magnetite by employing a strain-sensitive, bright-field scanning transmission electron microscopy approach. This method allows direct, real-time, high-resolution visualization of how lithiation proceeds along specific reaction pathways. We find that the initial intercalation process follows a two-phase reaction sequence, whereas further lithiation leads to the coexistence of three distinct phases within single nanoparticles, which has not been previously reported to the best of our knowledge. We use phase-field theory to model and describe these non-equilibrium reaction pathways, and to directly correlate the observed phase evolution with the battery's discharge performance.

  20. Observations of carbon nanotube oxidation in an aberration-corrected environmental transmission electron microscope.

    PubMed

    Koh, Ai Leen; Gidcumb, Emily; Zhou, Otto; Sinclair, Robert

    2013-03-26

    We report the first direct study on the oxidation of carbon nanotubes at the resolution of an aberration-corrected environmental transmission electron microscope (ETEM), as we locate and identify changes in the same nanotubes as they undergo oxidation at increasing temperatures in situ in the ETEM. Contrary to earlier reports that CNT oxidation initiates at the end of the tube and proceeds along its length, our findings show that only the outside graphene layer is being removed and, on occasion, the interior inner wall is oxidized, presumably due to oxygen infiltrating into the hollow nanotube through an open end or breaks in the tube. We believe that this work provides the foundation for a greater scientific understanding of the mechanism underlying the nanotube oxidation process, as well as guidelines to manipulate the nanotubes' structure or prevent their oxidation.

  1. Observations of Carbon Nanotube Oxidation in an Aberration-Corrected, Environmental Transmission Electron Microscope

    PubMed Central

    Koh, Ai Leen; Gidcumb, Emily; Zhou, Otto; Sinclair, Robert

    2013-01-01

    We report the first direct study on the oxidation of carbon nanotubes at the resolution of an aberration-corrected environmental transmission electron microscope (ETEM), as we locate and identify changes in the same nanotubes as they undergo oxidation at increasing temperatures in-situ in the ETEM. Contrary to earlier reports that CNT oxidation initiates at the end of the tube and proceeds along its length, our findings show that only the outside graphene layer is being removed and on occasion, the interior inner wall is oxidized, presumably due to oxygen infiltrating into the hollow nanotube through an open end or breaks in the tube. We believe that this work provides the foundation for much scientific understanding of the mechanism underlying the nanotube oxidation process, as well as guidelines to manipulate their structure or prevent their oxidation. PMID:23360330

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

    PubMed

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

    2014-01-01

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

  3. Analytical Transmission Electron Microscopy of Amphibole Fibers From the Lungs of Quebec Miners.

    PubMed

    Germine, Mark; Puffer, John H

    2015-01-01

    The objective of this study is to describe the morphology, molecular structure, and chemistry of amphibole fibers from lung samples from workers in the chrysotile mines at Asbestos and Thetford Mines, Quebec. A fibrous tremolite-actinolite contaminant in an asbestos ore sample from the deposit at Asbestos was used for comparison. Lattice imaging was performed using high-resolution transmission electron microscopy (HRTEM). Silica-rich amorphous coatings (SIRA) that may be related to carcinogenesis are noted on all of the HRTEM photographs of fibers retained in lung, but not on fiber surfaces of the bulk comparison sample. Fibers found in lung samples and in a bulk comparison sample are produced primarily by splitting of thicker crystals and, as such, might not be considered asbestos fibers on the basis of certain mineralogical criteria. Implications of SIRA coatings with respect to carcinogenesis are worthy of further study.

  4. Strain measurement in semiconductor heterostructures by scanning transmission electron microscopy.

    PubMed

    Müller, Knut; Rosenauer, Andreas; Schowalter, Marco; Zweck, Josef; Fritz, Rafael; Volz, Kerstin

    2012-10-01

    This article deals with the measurement of strain in semiconductor heterostructures from convergent beam electron diffraction patterns. In particular, three different algorithms in the field of (circular) pattern recognition are presented that are able to detect diffracted disc positions accurately, from which the strain in growth direction is calculated. Although the three approaches are very different as one is based on edge detection, one on rotational averages, and one on cross correlation with masks, it is found that identical strain profiles result for an In x Ga1-x N y As1-y /GaAs heterostructure consisting of five compressively and tensile strained layers. We achieve a precision of strain measurements of 7-9·10-4 and a spatial resolution of 0.5-0.7 nm over the whole width of the layer stack which was 350 nm. Being already very applicable to strain measurements in contemporary nanostructures, we additionally suggest future hardware and software designs optimized for fast and direct acquisition of strain distributions, motivated by the present studies.

  5. Automated Detection of Synapses in Serial Section Transmission Electron Microscopy Image Stacks

    PubMed Central

    Kreshuk, Anna; Koethe, Ullrich; Pax, Elizabeth; Bock, Davi D.; Hamprecht, Fred A.

    2014-01-01

    We describe a method for fully automated detection of chemical synapses in serial electron microscopy images with highly anisotropic axial and lateral resolution, such as images taken on transmission electron microscopes. Our pipeline starts from classification of the pixels based on 3D pixel features, which is followed by segmentation with an Ising model MRF and another classification step, based on object-level features. Classifiers are learned on sparse user labels; a fully annotated data subvolume is not required for training. The algorithm was validated on a set of 238 synapses in 20 serial 7197×7351 pixel images (4.5×4.5×45 nm resolution) of mouse visual cortex, manually labeled by three independent human annotators and additionally re-verified by an expert neuroscientist. The error rate of the algorithm (12% false negative, 7% false positive detections) is better than state-of-the-art, even though, unlike the state-of-the-art method, our algorithm does not require a prior segmentation of the image volume into cells. The software is based on the ilastik learning and segmentation toolkit and the vigra image processing library and is freely available on our website, along with the test data and gold standard annotations (http://www.ilastik.org/synapse-detection/sstem). PMID:24516550

  6. Video-frequency scanning transmission electron microscopy of moving gold nanoparticles in liquid.

    PubMed

    Ring, Elisabeth A; de Jonge, Niels

    2012-11-01

    Immobilized gold nanoparticles were imaged in a liquid containing water and 50% glycerol with scanning transmission electron microscopy (STEM). The specimen was enclosed in a liquid compartment formed by two silicon microchips with electron transparent windows. A series of images was recorded at video frequency with a spatial resolution of 1.5nm. The nanoparticles detached from their support after imaging them for several seconds at a magnification of 250,000. Their movement was found to be much different than the movement of nanoparticles moving freely in liquid as described by Brownian Motion. The direction of motion was not random-the nanoparticles moved either in a preferred direction, or radially outwards from the center of the image. The displacement of the gold nanoparticles over time was three orders of magnitude smaller than expected on the basis of Brownian Motion. This finding implies that nanoscale objects of flexible structure or freely floating, including nanoparticles and biological objects, can be imaged with nanoscale resolution, as long as they are in close proximity to a solid support structure.

  7. Nanoparticle suspensions enclosed in methylcellulose: a new approach for quantifying nanoparticles in transmission electron microscopy.

    PubMed

    Hacker, Christian; Asadi, Jalal; Pliotas, Christos; Ferguson, Sophie; Sherry, Lee; Marius, Phedra; Tello, Javier; Jackson, David; Naismith, James; Lucocq, John Milton

    2016-05-04

    Nanoparticles are of increasing importance in biomedicine but quantification is problematic because current methods depend on indirect measurements at low resolution. Here we describe a new high-resolution method for measuring and quantifying nanoparticles in suspension. It involves premixing nanoparticles in a hydrophilic support medium (methylcellulose) before introducing heavy metal stains for visualization in small air-dried droplets by transmission electron microscopy (TEM). The use of methylcellulose avoids artifacts of conventional negative stain-TEM by (1) restricting interactions between the nanoparticles, (2) inhibiting binding to the specimen support films and (3) reducing compression after drying. Methylcellulose embedment provides effective electron imaging of liposomes, nanodiscs and viruses as well as comprehensive visualization of nanoparticle populations in droplets of known size. These qualities facilitate unbiased sampling, rapid size measurement and estimation of nanoparticle numbers by means of ratio counting using a colloidal gold calibrant. Specimen preparation and quantification take minutes and require a few microliters of sample using only basic laboratory equipment and a standard TEM.

  8. Dark field imaging of biological macromolecules with the scanning transmission electron microscope

    PubMed Central

    Ohtsuki, Mitsuo; Isaacson, Michael S.; Crewe, A. V.

    1979-01-01

    A scanning transmission electron microscope (STEM) equipped with a field emission gun has been employed for the examination of biological macromolecules at high resolution. The quality of micrographs obtained with the STEM is dependent upon the quality of the substrate used to support biological objects because the image contrast in dark field is proportional to the mass density of the specimen. In order to reduce deleterious effects of the substrates on the image quality, we have developed a method of fabricating substrates consisting of very thin, very clean carbon films supported on very clean fenestrated plastic films. These films are approximately 15 Å thick. Well-known biological macromolecules such as glutamine synthetase and tobacco mosaic virus (both stained) and low-density lipoprotein and ferritin (both unstained were placed on these substrates and examined with the STEM by using various modes of contrast. The micrographs obtained by using the dark field mode of contrast employing an annular detector were free from phase contrast, as expected. Using this contrast mode, we have been able to directly observe (in-focus) 2.5- to 4.4-Å lattice spacings in the ferritin core. The effect of electron radiation damage on the helical structure of tobacco mosaic virus was also examined. Micrographs as well as corresponding optical diffraction patterns obtained with moderately low doses showed very clear helical structure from both sides of the virus. In addition, the (11.5 Å)-1 layer lines indicated the effective resolution attained on these particles. Images PMID:35788

  9. Nanoparticle suspensions enclosed in methylcellulose: a new approach for quantifying nanoparticles in transmission electron microscopy

    PubMed Central

    Hacker, Christian; Asadi, Jalal; Pliotas, Christos; Ferguson, Sophie; Sherry, Lee; Marius, Phedra; Tello, Javier; Jackson, David; Naismith, James; Lucocq, John Milton

    2016-01-01

    Nanoparticles are of increasing importance in biomedicine but quantification is problematic because current methods depend on indirect measurements at low resolution. Here we describe a new high-resolution method for measuring and quantifying nanoparticles in suspension. It involves premixing nanoparticles in a hydrophilic support medium (methylcellulose) before introducing heavy metal stains for visualization in small air-dried droplets by transmission electron microscopy (TEM). The use of methylcellulose avoids artifacts of conventional negative stain-TEM by (1) restricting interactions between the nanoparticles, (2) inhibiting binding to the specimen support films and (3) reducing compression after drying. Methylcellulose embedment provides effective electron imaging of liposomes, nanodiscs and viruses as well as comprehensive visualization of nanoparticle populations in droplets of known size. These qualities facilitate unbiased sampling, rapid size measurement and estimation of nanoparticle numbers by means of ratio counting using a colloidal gold calibrant. Specimen preparation and quantification take minutes and require a few microliters of sample using only basic laboratory equipment and a standard TEM. PMID:27141843

  10. Rare-earth-doped nanophosphors for multicolor cathodoluminescence nanobioimaging using scanning transmission electron microscopy.

    PubMed

    Furukawa, Taichi; Fukushima, Shoichiro; Niioka, Hirohiko; Yamamoto, Naoki; Miyake, Jun; Araki, Tsutomu; Hashimoto, Mamoru

    2015-05-01

    We describe rare-earth-doped nanophosphors (RE-NPs) for biological imaging using cathodoluminescence(CL) microscopy based on scanning transmission electron microscopy (STEM). We report the first demonstration of multicolor CL nanobioimaging using STEM with nanophosphors. The CL spectra of the synthesized nanophosphors (Y2O3∶Eu, Y2O3∶Tb) were sufficiently narrow to be distinguished. From CL images of RE-NPs on an elastic carbon-coated copper grid, the spatial resolution was beyond the diffraction limit of light.Y2O3∶Tb and Y2O3∶Eu RE-NPs showed a remarkable resistance against electron beam exposure even at high acceleration voltage (80 kV) and retained a CL intensity of more than 97% compared with the initial intensity for 1 min. In biological CL imaging with STEM, heavy-metal-stained cell sections containing the RE-NPs were prepared,and both the CL images of RE-NPs and cellular structures, such as mitochondria, were clearly observed from STEM images with high contrast. The cellular CL imaging using RE-NPs also had high spatial resolution even though heavy-metal-stained cells are normally regarded as highly scattering media. Moreover, since theRE-NPs exhibit photoluminescence (PL) excited by UV light, they are useful for multimodal correlative imaging using CL and PL.

  11. 21 CFR 1311.05 - Standards for technologies for electronic transmission of orders.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Standards for technologies for electronic transmission of orders. 1311.05 Section 1311.05 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF... technologies for electronic transmission of orders. (a) A registrant or a person with power of attorney to...

  12. Scanning Transmission Electron Microscopy Using Selective High-Order Laue Zones: Three-Dimensional Atomic Ordering in Sodium Cobaltate

    NASA Astrophysics Data System (ADS)

    Huang, F.-T.; Gloter, A.; Chu, M.-W.; Chou, F. C.; Shu, G. J.; Liu, L.-K.; Chen, C. H.; Colliex, C.

    2010-09-01

    A new scanning transmission electron microscopy (STEM) imaging technique using high-order Laue zones (named HOLZ-STEM), a diffraction contrast which has been strenuously avoided or minimized in traditional STEM imaging, can be used to obtain the additional 1D periodic information along the electron propagation axis without sacrificing atomic resolution in the lateral (2D) dimension. HOLZ-STEM has been demonstrated to resolve the 3D long-range Na ordering of Na0.71CoO2. Direct evidence of spiral-like Na-trimer chains twisting along the c axis is unambiguously established in real space.

  13. Magnified pseudo-elemental map of atomic column obtained by Moiré method in scanning transmission electron microscopy.

    PubMed

    Kondo, Yukihito; Okunishi, Eiji

    2014-10-01

    Moiré method in scanning transmission electron microscopy allows observing a magnified two-dimensional atomic column elemental map of a higher pixel resolution with a lower electron dose unlike conventional atomic column mapping. The magnification of the map is determined by the ratio between the pixel size and the lattice spacing. With proper ratios for the x and y directions, we could observe magnified elemental maps, homothetic to the atomic arrangement in the sample of SrTiO3 [0 0 1]. The map showed peaks at all expected oxygen sites in SrTiO3 [0 0 1].

  14. Advanced fertility diagnosis in stallion semen using transmission electron microscopy.

    PubMed

    Pesch, Sandra; Bostedt, Hartwig; Failing, Klaus; Bergmann, Martin

    2006-02-01

    Routine semen analysis of stallions is based on light microscopy (LM). However, there are still a number of animals that are subfertile or even infertile not being identified with conventional semen analysis. The objective of this study was to investigate the suitability of transmission electron microscopy (TEM) for advanced fertility diagnosis in stallion. We examined ejaculates of 46 stallions with known fertility. Animals were divided into three different groups: group 1, fertile stallions (pregnant mares> or =70%, n=29); group 2, subfertile stallions (pregnant mares 10-69%, n=14); group 3, infertile stallions (pregnant mares<10%, n=3). Ejaculates were collected in spring 2002. Conventional semen analysis (volume, sperm concentration, motility, live:dead ratio and percentage of morphologically normal sperm) was immediately performed after semen collection. Ultrastructural analysis included the evaluation of 200 acrosomes, heads, midpieces and cross-sections of tails as well as 100 longitudinal sections of tails from every ejaculate. Using LM, we found a significant increase of morphological deviations from 24.5% (x ) in group 1 to 34.5% in group 2 and 73.5% in group 3. Using TEM, we found a significant increase of detached acrosomes from 6.1% in group 1 to 7.6% in group 2 and 21.4% in group 3. Deviations in tubule pattern were also increased (but not significant) from 2.7% in fertile and 2.8% in subfertile to 11.4% in infertile stallions as well as multiple tails from 1.9% in fertile to 2.0% in subfertile and 8.9% in infertile. Our data indicate that TEM is suitable for advanced fertility diagnostic in stallions, giving a connection between fertility and morphology. It suggests that the most likely reason for sub- and infertility in stallion in case of increased LM pathomorphology of semen are acrosomal alterations, especially detached acrosomes.

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  16. Correlative in-resin super-resolution and electron microscopy using standard fluorescent proteins

    PubMed Central

    Johnson, Errin; Seiradake, Elena; Jones, E. Yvonne; Davis, Ilan; Grünewald, Kay; Kaufmann, Rainer

    2015-01-01

    We introduce a method for correlative in-resin super-resolution fluorescence and electron microscopy (EM) of biological structures in mammalian culture cells. Cryo-fixed resin embedded samples offer superior structural preservation, performing in-resin super-resolution, however, remains a challenge. We identified key aspects of the sample preparation procedure of high pressure freezing, freeze substitution and resin embedding that are critical for preserving fluorescence and photo-switching of standard fluorescent proteins, such as mGFP, mVenus and mRuby2. This enabled us to combine single molecule localization microscopy with transmission electron microscopy imaging of standard fluorescent proteins in cryo-fixed resin embedded cells. We achieved a structural resolution of 40–50 nm (~17 nm average single molecule localization accuracy) in the fluorescence images without the use of chemical fixation or special fluorophores. Using this approach enabled the correlation of fluorescently labeled structures to the ultrastructure in the same cell at the nanometer level and superior structural preservation. PMID:25823571

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

    PubMed

    El Mel, Abdel-Aziz; Bittencourt, Carla

    2016-06-07

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

  18. Bright-field scanning confocal electron microscopy using a double aberration-corrected transmission electron microscope.

    PubMed

    Wang, Peng; Behan, Gavin; Kirkland, Angus I; Nellist, Peter D; Cosgriff, Eireann C; D'Alfonso, Adrian J; Morgan, Andrew J; Allen, Leslie J; Hashimoto, Ayako; Takeguchi, Masaki; Mitsuishi, Kazutaka; Shimojo, Masayuki

    2011-06-01

    Scanning confocal electron microscopy (SCEM) offers a mechanism for three-dimensional imaging of materials, which makes use of the reduced depth of field in an aberration-corrected transmission electron microscope. The simplest configuration of SCEM is the bright-field mode. In this paper we present experimental data and simulations showing the form of bright-field SCEM images. We show that the depth dependence of the three-dimensional image can be explained in terms of two-dimensional images formed in the detector plane. For a crystalline sample, this so-called probe image is shown to be similar to a conventional diffraction pattern. Experimental results and simulations show how the diffracted probes in this image are elongated in thicker crystals and the use of this elongation to estimate sample thickness is explored.

  19. Metal particles in a ceramic matrix--scanning electron microscopy and transmission electron microscopy characterization.

    PubMed

    Konopka, K

    2006-09-01

    This paper is concerned with ceramic matrix (Al(2)O(3)) composites with introduced metal particles (Ni, Fe). The composites were obtained via sintering of powders under very high pressure (2.5 GPa). Scanning electron microscopy and transmission electron microscopy were chosen as the tools for the identification and description of the shape, size and distribution of the metal particles. The Al(2)O(3)-Ni composite contained agglomerates of the Ni particles surrounded by ceramic grains and nanometre-size Ni particles located inside the ceramic grains and at the ceramic grain boundaries. In the Al(2)O(3)-Fe composite, the Fe particles were mostly surrounded by ceramic grains. Moreover, holes left by the Fe particles were found. The high pressure used in the fabrication of the composites changed the shape of the metal and ceramic powder grains via plastic deformation.

  20. Ultralow Energy Electron Attachment at Sub-Millielectron Volt Resolution

    NASA Technical Reports Server (NTRS)

    Chutjian, A.; Kortyna, A.; Darrach, M. R.; Howe, P. -T.

    1999-01-01

    The technique of rare-gas photoionization has been extended by use of direct laser ionization to electron energies epsilon in the range 0-100 meV, with a resolution Delta(epsilon) of 0.4-0.5 meV (FWHM). Tunable UV light at (Lambda)276 nm is produced using a pulsed Nd:YAG laser and nonlinear mixing techniques. The beam is frequency tripled in a pulsed jet of xenon. The VUV radiation, tunable at (Lambda)92 nm, is then used to photoionize Xe at its 2P(sub 1/2) threshold (single-photon ionization). The photoelectrons produced interact with admixed target gas to generate negative ions through the s-wave capture process. Recent results in electron attachment to SF(sub 6) will be reported which show resonance structure at the opening of the ground-state vibrational channels. This structure corresponds to the process of vibrational excitation + attachment, which is superimposed on the underlying s-wave (direct) capture process. It should be a general phenomenon, present in a wide variety of zero-energy electron attaching molecules.

  1. Electron beam direct write: shaped beam overcomes resolution concerns

    NASA Astrophysics Data System (ADS)

    Stolberg, Ines; Pain, Laurent; Kretz, Johannes; Boettcher, Monika; Doering, Hans-Joachim; Gramss, Juergen; Hahmann, Peter

    2007-02-01

    In semiconductor industry time to market is one of the key success factors. Therefore fast prototyping and low-volume production will become extremely important for developing process technologies that are well ahead of the current technological level. Electron Beam Lithography has been launched for industrial use as a direct write technology for these types of applications. However, limited throughput rates and high tool complexity have been seen as the major concerns restricting the industrial use of this technology. Nowadays this begins to change. Variable Shaped Beam (VSB) writers have been established in Electron Beam Direct Write (EBDW) on Si or GaAs. In the paper semiconductor industry requirements to EBDW will be outlined. Behind this background the Vistec SB3050 lithography system will be reviewed. The achieved resolution enhancement of the VSB system down to the 22nm node exposure capability will be discussed in detail; application examples will be given. Combining EBDW in a Mix and Match technology with optical lithography is one way to utilize the high flexibility advantage of this technology and to overcome existing throughput concerns. However, to some extend a common Single Electron Beam Technology (SBT) will always be limited in throughput. Therefore Vistec's approach of a system that is based on the massive parallelisation of beams (MBT), which was initially pursued in a European Project, will also be discussed.

  2. High Resolution Studies of Electron Attachment to Molecules

    SciTech Connect

    Braun, M.; Ruf, M.-W.; Hotop, H.; Fabrikant, I. I.

    2009-05-02

    In this paper, we survey recent progress in studies of anion formation via (dissociative) electron attachment (DEA) to simple molecules, as measured with the laser photoelectron attachment (LPA) method at high resolution. The limiting (E{yields}0) threshold behavior of the cross sections is elucidated for s-wave and p-wave attachment. Cusps at onsets for vibrational excitation (VE), due to interaction of the DEA channnel with the VE channel, are clearly detected, and vibrational Feshbach resonances just below vibrational onsets are observed for molecules with sufficiently strong long-range attraction between the electron and the molecule. From the LPA anion yields, absolute DEA cross sections (energy range typically E = 0.001-2 eV) are determined with reference to rate coefficients for thermal electron attachment at the appropriate gas temperature (normally T{sub G} = 300 K). The experimental data are compared with theoretical cross sections, calculated within the framework of an R-matrix or an Effective Range theory approach.

  3. Structural and Physicochemical Characterization of Spirulina (Arthrospira maxima) Nanoparticles by High-Resolution Electron Microscopic Techniques.

    PubMed

    Neri-Torres, Elier Ekberg; Chanona-Pérez, Jorge J; Calderón, Hector A; Torres-Figueredo, Neil; Chamorro-Cevallos, German; Calderón-Domínguez, Georgina; Velasco-Bedrán, Hugo

    2016-08-01

    The objective of this work was to obtain Spirulina (Arthrospira maxima) nanoparticles (SNPs) by using high-impact mechanical milling and to characterize them by electron microscopy and spectroscopy techniques. The milling products were analyzed after various processing times (1-4 h), and particle size distribution and number mean size (NMS) were determined by analysis of high-resolution scanning electron microscopic images. The smallest particles are synthesized after 3 h of milling, had an NMS of 55.6±3.6 nm, with 95% of the particles being smaller than 100 nm. High-resolution transmission electron microscopy showed lattice spacing of ~0.27±0.015 nm for SNPs. The corresponding chemical composition was obtained by energy-dispersive X-ray spectroscopy, and showed the presence of Ca, Fe, K, Mg, Na, and Zn. The powder flow properties showed that the powder density was higher when the average nanoparticle size is smaller. They showed free flowability and an increase in their specific surface area (6.89±0.23 m2/g) up to 12-14 times larger than the original material (0.45±0.02 m2/g). Fourier transform infrared spectroscopy suggested that chemical damage related to the milling is not significant.

  4. High time resolution electron measurement by Fast Electron energy Spectrum Analyzer (FESA)

    SciTech Connect

    Saito, Yoshifumi; Fujimoto, Masaki; Maezawa, Kiyoshi; Shinohara, Iku; Tsuda, Yuichi; Sasaki, Shintaro; Kojima, Hirotsugu

    2009-06-16

    We have newly developed an electron energy analyzer FESA (Fast Electron energy Spectrum Analyzer) for a future magnetospheric satellite mission SCOPE. The SCOPE mission is designed in order that observational studies from the cross-scale coupling viewpoint are enabled. One of the key observations necessary for the SCOPE mission is high-time resolution electron measurement. Eight FESAs on a spinning spacecraft are capable of measuring three dimensional electron distribution function with time resolution of 8 msec. FESA consists of two electrostatic analyzers that are composed of three nested hemispherical deflectors. Single FESA functions as four top-hat type electrostatic analyzers that can measure electrons with four different energies simultaneously. By measuring the characteristics of the test model FESA, we proved the validity of the design concept of FESA. Based on the measured characteristics, we designed FESA optimized for the SCOPE mission. This optimized analyzer has good enough performance to measure three dimensional electron distribution functions around the magnetic reconnection region in the Earth's magnetotail.

  5. In situ electronic characterization of graphene nanoconstrictions fabricated in a transmission electron microscope.

    PubMed

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

    2011-12-14

    We report electronic measurements on high-quality graphene nanoconstrictions (GNCs) fabricated in a transmission electron microscope (TEM), and the first measurements on GNC conductance with an accurate measurement of constriction width down to 1 nm. To create the GNCs, freely suspended graphene ribbons were fabricated using few-layer graphene grown by chemical vapor deposition. The ribbons were loaded into the TEM, and a current-annealing procedure was used to clean the material and improve its electronic characteristics. The TEM beam was then used to sculpt GNCs to a series of desired widths in the range 1-700 nm; after each sculpting step, the sample was imaged by TEM and its electronic properties were measured in situ. GNC conductance was found to be remarkably high, comparable to that of exfoliated graphene samples of similar size. The GNC conductance varied with width approximately as G(w)=(e2/h)w0.75, where w is the constriction width in nanometers. GNCs support current densities greater than 120 μA/nm2, 2 orders of magnitude higher than that which has been previously reported for graphene nanoribbons and 2000 times higher than that reported for copper.

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

  7. Solving the Accelerator-Condenser Coupling Problem in a Nanosecond Dynamic Transmission Electron Microscope

    SciTech Connect

    Reed, B W; LaGrange, T; Shuttlesworth, R M; Gibson, D J; Campbell, G H; Browning, N D

    2009-12-29

    We describe a modification to a transmission electron microscope (TEM) that allows it to briefly (using a pulsed-laser-driven photocathode) operate at currents in excess of 10 mA while keeping the effects of condenser lens aberrations to a minimum. This modification allows real-space imaging of material microstructure with a resolution of order 10 nm over regions several {micro}m across with an exposure time of 15 ns. This is more than 6 orders of magnitude faster than typical video-rate TEM imaging. The key is the addition of a weak magnetic lens to couple the large-diameter high-current beam exiting the accelerator into the acceptance aperture of a conventional TEM condenser lens system. We show that the performance of the system is essentially consistent with models derived from ray tracing and finite element simulations. The instrument can also be operated as a conventional TEM by using the electron gun in a thermionic mode. The modification enables very high electron current densities in {micro}m-sized areas and could also be used in a non-pulsed system for high-throughput imaging and analytical TEM.

  8. In situ nanoindentation in a transmission electron microscope

    NASA Astrophysics Data System (ADS)

    Minor, Andrew Murphy

    This dissertation presents the development of the novel mechanical testing technique of in situ nanoindentation in a transmission electron microscope (TEM). This technique makes it possible to simultaneously observe and quantify the mechanical behavior of nano-scale volumes of solids. Chapter 2 details the unique specimen preparation techniques employed to meet the geometrical constraints of the in situ experiments. These techniques include bulk silicon micromachining and the use of a focused ion beam. In section 2.4 a method of voltage-controlled mechanical testing is derived theoretically and proven experimentally. This method enables the quantification of the mechanical behavior during in situ nanoindentation experiments. Three classes of material systems were studied with this new technique: (1) bulk single crystal, (2) a soft thin film on a harder substrate and (3) a hard thin film on a softer substrate. Section 3.2 provides the first direct evidence of dislocation nucleation in single crystal silicon at room temperature. In contrast to the observation of phase transformations during conventional indentation experiments, the unique geometry employed for the in situ experiments resulted in dislocation plasticity. In section 3.3 results from in situ nanoindentation of Al films on Si substrates are presented. These results include the correlation of the microstructural deformation behavior with load vs. displacement data. It is shown that a sharp change in the force-displacement response at the elastic-to-plastic transition signifies the nucleation of dislocations. Additionally, the softening of sub-micron grains with size is observed. Section 3.4 discussed the influence of the substrate on the indentation response of two thin film/substrate systems where the films were harder than the substrate. Amorphous diamond on Si and epitaxial TiN on MgO (001) systems were studied. It was found that the deformation in the harder films was controlled by the deformation in

  9. Aberration-corrected scanning transmission electron microscopy for complex transition metal oxides

    NASA Astrophysics Data System (ADS)

    Qing-Hua, Zhang; Dong-Dong, Xiao; Lin, Gu

    2016-06-01

    Lattice, charge, orbital, and spin are the four fundamental degrees of freedom in condensed matter, of which the interactive coupling derives tremendous novel physical phenomena, such as high-temperature superconductivity (high-T c SC) and colossal magnetoresistance (CMR) in strongly correlated electronic system. Direct experimental observation of these freedoms is essential to understanding the structure-property relationship and the physics behind it, and also indispensable for designing new materials and devices. Scanning transmission electron microscopy (STEM) integrating multiple techniques of structure imaging and spectrum analysis, is a comprehensive platform for providing structural, chemical and electronic information of materials with a high spatial resolution. Benefiting from the development of aberration correctors, STEM has taken a big breakthrough towards sub-angstrom resolution in last decade and always steps forward to improve the capability of material characterization; many improvements have been achieved in recent years, thereby giving an in-depth insight into material research. Here, we present a brief review of the recent advances of STEM by some representative examples of perovskite transition metal oxides; atomic-scale mapping of ferroelectric polarization, octahedral distortions and rotations, valence state, coordination and spin ordering are presented. We expect that this brief introduction about the current capability of STEM could facilitate the understanding of the relationship between functional properties and these fundamental degrees of freedom in complex oxides. Project supported by the National Key Basic Research Project, China (Grant No. 2014CB921002), the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB07030200), and the National Natural Science Foundation of China (Grant Nos. 51522212 and 51421002).

  10. Three-dimensional bright-field scanning transmission electron microscopy elucidate novel nanostructure in microbial biofilms.

    PubMed

    Hickey, William J; Shetty, Ameesha R; Massey, Randall J; Toso, Daniel B; Austin, Jotham

    2017-01-01

    Bacterial biofilms play key roles in environmental and biomedical processes, and understanding their activities requires comprehension of their nanoarchitectural characteristics. Electron microscopy (EM) is an essential tool for nanostructural analysis, but conventional EM methods are limited in that they either provide topographical information alone, or are suitable for imaging only relatively thin (<300 nm) sample volumes. For biofilm investigations, these are significant restrictions. Understanding structural relations between cells requires imaging of a sample volume sufficiently large to encompass multiple cells and the capture of both external and internal details of cell structure. An emerging EM technique with such capabilities is bright-field scanning transmission electron microscopy (BF-STEM) and in the present report BF-STEM was coupled with tomography to elucidate nanostructure in biofilms formed by the polycyclic aromatic hydrocarbon-degrading soil bacterium, Delftia acidovorans Cs1-4. Dual-axis BF-STEM enabled high-resolution 3-D tomographic recontructions (6-10 nm) visualization of thick (1250 and 1500 nm) sections. The 3-D data revealed that novel extracellular structures, termed nanopods, were polymorphic and formed complex networks within cell clusters. BF-STEM tomography enabled visualization of conduits formed by nanopods that could enable intercellular movement of outer membrane vesicles, and thereby enable direct communication between cells. This report is the first to document application of dual-axis BF-STEM tomography to obtain high-resolution 3-D images of novel nanostructures in bacterial biofilms. Future work with dual-axis BF-STEM tomography combined with correlative light electron microscopy may provide deeper insights into physiological functions associated with nanopods as well as other nanostructures.

  11. Nanoscale analysis of unstained biological specimens in water without radiation damage using high-resolution frequency transmission electric-field system based on FE-SEM

    SciTech Connect

    Ogura, Toshihiko

    2015-04-10

    Scanning electron microscopy (SEM) has been widely used to examine biological specimens of bacteria, viruses and proteins. Until now, atmospheric and/or wet biological specimens have been examined using various atmospheric holders or special equipment involving SEM. Unfortunately, they undergo heavy radiation damage by the direct electron beam. In addition, images of unstained biological samples in water yield poor contrast. We recently developed a new analytical technology involving a frequency transmission electric-field (FTE) method based on thermionic SEM. This method is suitable for high-contrast imaging of unstained biological specimens. Our aim was to optimise the method. Here we describe a high-resolution FTE system based on field-emission SEM; it allows for imaging and nanoscale examination of various biological specimens in water without radiation damage. The spatial resolution is 8 nm, which is higher than 41 nm of the existing FTE system. Our new method can be easily utilised for examination of unstained biological specimens including bacteria, viruses and protein complexes. Furthermore, our high-resolution FTE system can be used for diverse liquid samples across a broad range of scientific fields, e.g. nanoparticles, nanotubes and organic and catalytic materials. - Highlights: • We developed a high-resolution frequency transmission electric-field (FTE) system. • High-resolution FTE system is introduced in the field-emission SEM. • The spatial resolution of high-resolution FTE method is 8 nm. • High-resolution FTE system enables observation of the intact IgM particles in water.

  12. Compact soft x-ray transmission microscopy with sub-50 nm spatial resolution.

    PubMed

    Kim, Kyong Woo; Kwon, Youngman; Nam, Ki-Yong; Lim, Jong-Hyeok; Kim, Kyu-Gyum; Chon, Kwon Su; Kim, Byoung Hoon; Kim, Dong Eon; Kim, JinGon; Ahn, Byoung Nam; Shin, Hyun Joon; Rah, Seungyu; Kim, Ki-Ho; Chae, Jin Seok; Gweon, Dae Gab; Kang, Dong Woo; Kang, Sung Hoon; Min, Jin Young; Choi, Kyu-Sil; Yoon, Seong Eon; Kim, Eun-A; Namba, Yoshiharu; Yoon, Kwon-Ha

    2006-03-21

    In this paper, the development of compact transmission soft x-ray microscopy (XM) with sub-50 nm spatial resolution for biomedical applications is described. The compact transmission soft x-ray microscope operates at lambda = 2.88 nm (430 eV) and is based on a tabletop regenerative x-ray source in combination with a tandem ellipsoidal condenser mirror for sample illumination, an objective micro zone plate and a thinned back-illuminated charge coupled device to record an x-ray image. The new, compact x-ray microscope system requires the fabrication of proper x-ray optical devices in order to obtain high-quality images. For an application-oriented microscope, the alignment procedure is fully automated via computer control through a graphic user interface. In imaging studies using our compact XM system, a gold mesh image was obtained with 45 nm resolution at x580 magnification and 1 min exposure. Images of a biological sample (Coscinodiscus oculoides) were recorded.

  13. HIGH-RESOLUTION ELECTRON MICROSCOPIC ANALYSIS OF THE AMYLOID FIBRIL

    PubMed Central

    Shirahama, Tsuranobu; Cohen, Alan S.

    1967-01-01

    The ultrastructural organization of the fibrous component of amyloid has been analyzed by means of high resolution electron microscopy of negatively stained isolated amyloid fibrils and of positively stained amyloid fibrils in thin tissue sections. It was found that a number of subunits could be resolved according to their dimensions. The following structural organization is proposed. The amyloid fibril, the fibrous component of amyloid as seen in electron microscopy of thin tissue sections, consists of a number of filaments aggregated side-by-side. These amyloid filaments are approximately 75–80 A in diameter and consist of five (or less likely six) subunits (amyloid protofibrils) which are arranged parallel to each other, longitudinal or slightly oblique to the long axis of the filament. The filament has often seemed to disperse into several longitudinal rows. The amyloid protofibril is about 25–35 A wide and appears to consist of two or three subunit strands helically arranged with a 35–50-A repeat (or, less likely, is composed of globular subunits aggregated end-to-end). These amyloid subprotofibrillar strands measure approximately 10–15 A in diameter. PMID:6036530

  14. Stereological characterization of the {gamma}' particles in a nickel base superalloy: Comparison between transmission electron microscopy and atomic force microscopy techniques

    SciTech Connect

    Risbet, M. Feaugas, X.; Guillemer-Neel, C.; Clavel, M.

    2008-09-15

    Critical comparison of transmission electron microscopy and atomic force microscopy techniques was provided concerning size measurements of {gamma}' precipitates in a nickel-base superalloy. The divergence between results is explained in terms of the resolution limit for atomic force microscopy, linked both to the tip dimension and the diameter of the investigated particles.

  15. In Situ Observation of Carbonaceous Material in the Matrices of CV and CM Carbonaceous Chondrites: Preliminary Results from Energy Filtered Transmission Electron Microscopy

    NASA Technical Reports Server (NTRS)

    Brearley, A. J.; Abreu, N. M.

    2001-01-01

    Energy filtered transmission electron microscopy shows that organic matter can be detected in situ in the matrices of carbonaceous chondrites at a spatial resolution of at least 1 nm. In CM chondrites, carbon is often associated with sulfide particles. Additional information is contained in the original extended abstract.

  16. Strain mapping with nm-scale resolution for the silicon-on-insulator generation of semiconductor devices by advanced electron microscopy

    SciTech Connect

    Cooper, David; Denneulin, Thibaud; Barnes, Jean-Paul; Hartmann, Jean-Michel; Hutin, Louis; Le Royer, Cyrille; Beche, Armand; Rouviere, Jean-Luc

    2012-12-15

    Strain engineering in the conduction channel is a cost effective method of boosting the performance in state-of-the-art semiconductor devices. However, given the small dimensions of these devices, it is difficult to quantitatively measure the strain with the required spatial resolution. Three different transmission electron microscopy techniques, high-angle annular dark field scanning transmission electron microscopy, dark field electron holography, and nanobeam electron diffraction have been applied to measure the strain in simple bulk and SOI calibration specimens. These techniques are then applied to different gate length SiGe SOI pFET devices in order to measure the strain in the conduction channel. For these devices, improved spatial resolution is required, and strain maps with spatial resolutions as good as 1 nm have been achieved. Finally, we discuss the relative advantages and disadvantages of using these three different techniques when used for strain measurement.

  17. R-Matrix Analysis of 238U High Resolution Neutron Transmissions and Capture Cross Sections in the Energy Range 0 keV to 20 keV

    SciTech Connect

    Derrien, Herve; Leal, Luiz C; Larson, Nancy M

    2009-01-01

    The neutron resonance parameters of 238U were obtained from a SAMMY analysis of high-resolution neutron transmission measurements and high-resolution capture cross section measurements performed at the Oak Ridge Electron Linear Accelerator (ORELA) in the years 1970-1990 and from more recent transmission and capture cross section measurements performed at the Geel Linear Accelerator (GELINA). Compared with previous evaluations, the energy range for this resonance analysis was extended from 10 to 20 keV, taking advantage of the high resolution of the most recent ORELA transmission measurements. The experimental database and the method of analysis are described in this report. The neutron transmissions and the capture cross sections calculated with the resonance parameters are compared with the experimental data. A description is given of the statistical properties of the resonance parameters and of the recommended values of the average parameters. The new evaluation results in a slight decrease of the effective capture resonance integral and improves the prediction of integral thermal benchmarks by 70 to 200 pcm.

  18. Correlative fluorescence microscopy and scanning transmission electron microscopy of quantum-dot-labeled proteins in whole cells in liquid.

    PubMed

    Dukes, Madeline J; Peckys, Diana B; de Jonge, Niels

    2010-07-27

    Correlative fluorescence microscopy and transmission electron microscopy (TEM) is a state-of-the-art microscopy methodology to study cellular function, combining the functionality of light microscopy with the high resolution of electron microscopy. However, this technique involves complex sample preparation procedures due to its need for either thin sections or frozen samples for TEM imaging. Here, we introduce a novel correlative approach capable of imaging whole eukaryotic cells in liquid with fluorescence microscopy and with scanning transmission electron microscopy (STEM); there is no additional sample preparation necessary for the electron microscopy. Quantum dots (QDs) were bound to epidermal growth factor (EGF) receptors of COS7 fibroblast cells. Fixed whole cells in saline water were imaged with fluorescence microscopy and subsequently with STEM. The STEM images were correlated with fluorescence images of the same cellular regions. QDs of dimensions 7x12 nm were visible in a 5 microm thick layer of saline water, consistent with calculations. A spatial resolution of 3 nm was achieved on the QDs.

  19. Correlative Fluorescence Microscopy and Scanning Transmission Electron Microscopy of Quantum Dot Labeled Proteins in Whole Cells in Liquid

    PubMed Central

    Dukes, Madeline J.; Peckys, Diana B.; de Jonge, Niels

    2010-01-01

    Correlative fluorescence microscopy and transmission electron microscopy (TEM) is a state-of-the-art microscopy methodology to study cellular function, combining the functionality of light microscopy with the high resolution of electron microscopy. However, this technique involves complex sample preparation procedures due to its need for either thin sections or frozen samples for TEM imaging. Here, we introduce a novel correlative approach capable of imaging whole eukaryotic cells in liquid with fluorescence microscopy and with scanning transmission electron microscopy (STEM); there is no additional sample preparation necessary for the electron microscopy. Quantum dots (QDs) were bound to epidermal growth factor (EGF) receptors of COS7 fibroblast cells. Fixed whole cells in saline water were imaged with fluorescence microscopy and subsequently with STEM. The STEM images were correlated with fluorescence images of the same cellular regions. QDs of dimensions 7 × 12 nm were visible in a 5 μm thick layer of saline water, consistent with calculations. A spatial resolution of 3 nm was achieved on the QDs. PMID:20550177

  20. Common Bias Readout for TES Array on Scanning Transmission Electron Microscope

    NASA Astrophysics Data System (ADS)

    Yamamoto, R.; Sakai, K.; Maehisa, K.; Nagayoshi, K.; Hayashi, T.; Muramatsu, H.; Nakashima, Y.; Mitsuda, K.; Yamasaki, N. Y.; Takei, Y.; Hidaka, M.; Nagasawa, S.; Maehata, K.; Hara, T.

    2016-07-01

    A transition edge sensor (TES) microcalorimeter array as an X-ray sensor for a scanning transmission electron microscope system is being developed. The technical challenge of this system is a high count rate of ˜ 5000 counts/second/array. We adopted a 64 pixel array with a parallel readout. Common SQUID bias, and common TES bias are planned to reduce the number of wires and the resources of a room temperature circuit. The reduction rate of wires is 44 % when a 64 pixel array is read out by a common bias of 8 channels. The possible degradation of the energy resolution has been investigated by simulations and experiments. The bias fluctuation effects of a series connection are less than those of a parallel connection. Simple calculations expect that the fluctuations of the common SQUID bias and common TES bias in a series connection are 10^{-7} and 10^{-3}, respectively. We constructed 8 SQUIDs which are connected to 8 TES outputs and a room temperature circuit for common bias readout and evaluated experimentally. Our simulation of crosstalk indicates that at an X-ray event rate of 500 cps/pixel, crosstalk will broaden a monochromatic line by about 0.01 %, or about 1.5 eV at 15 keV. Thus, our design goal of 10 eV energy resolution across the 0.5-15 keV band should be achievable.

  1. Local sample thickness determination via scanning transmission electron microscopy defocus series.

    PubMed

    Beyer, A; Straubinger, R; Belz, J; Volz, K

    2016-05-01

    The usable aperture sizes in (scanning) transmission electron microscopy ((S)TEM) have significantly increased in the past decade due to the introduction of aberration correction. In parallel with the consequent increase of convergence angle the depth of focus has decreased severely and optical sectioning in the STEM became feasible. Here we apply STEM defocus series to derive the local sample thickness of a TEM sample. To this end experimental as well as simulated defocus series of thin Si foils were acquired. The systematic blurring of high resolution high angle annular dark field images is quantified by evaluating the standard deviation of the image intensity for each image of a defocus series. The derived dependencies exhibit a pronounced maximum at the optimum defocus and drop to a background value for higher or lower values. The full width half maximum (FWHM) of the curve is equal to the sample thickness above a minimum thickness given by the size of the used aperture and the chromatic aberration of the microscope. The thicknesses obtained from experimental defocus series applying the proposed method are in good agreement with the values derived from other established methods. The key advantages of this method compared to others are its high spatial resolution and that it does not involve any time consuming simulations.

  2. Structural defects in cubic semiconductors characterized by aberration-corrected scanning transmission electron microscopy.

    PubMed

    Arroyo Rojas Dasilva, Yadira; Kozak, Roksolana; Erni, Rolf; Rossell, Marta D

    2016-09-28

    The development of new electro-optical devices and the realization of novel types of transistors require a profound understanding of the structural characteristics of new semiconductor heterostructures. This article provides a concise review about structural defects which occur in semiconductor heterostructures on the basis of micro-patterned Si substrates. In particular, one- and two-dimensional crystal defects are being discussed which are due to the plastic relaxation of epitaxial strain caused by the misfit of crystal lattices. Besides a few selected examples from literature, we treat in particular crystal defects occurring in GaAs/Si, Ge/Si and β-SiC/Si structures which are studied by high-resolution annular dark-field scanning transmission electron microscopy. The relevance of this article is twofold; firstly, it should provide a collection of data which are of help for the identification and characterization of defects in cubic semiconductors by means of atomic-resolution imaging, and secondly, the experimental data shall provide a basis for advancing the understanding of device characteristics with the aid of theoretical modelling by considering the defective nature of strained semiconductor heterostructures.

  3. Revolving scanning transmission electron microscopy: correcting sample drift distortion without prior knowledge.

    PubMed

    Sang, Xiahan; LeBeau, James M

    2014-03-01

    We report the development of revolving scanning transmission electron microscopy--RevSTEM--a technique that enables characterization and removal of sample drift distortion from atomic resolution images without the need for a priori crystal structure information. To measure and correct the distortion, we acquire an image series while rotating the scan coordinate system between successive frames. Through theory and experiment, we show that the revolving image series captures the information necessary to analyze sample drift rate and direction. At atomic resolution, we quantify the image distortion using the projective standard deviation, a rapid, real-space method to directly measure lattice vector angles. By fitting these angles to a physical model, we show that the refined drift parameters provide the input needed to correct distortion across the series. We demonstrate that RevSTEM simultaneously removes the need for a priori structure information to correct distortion, leads to a dramatically improved signal-to-noise ratio, and enables picometer precision and accuracy regardless of drift rate.

  4. Performance of high-resolution SEM/EDX systems equipped with transmission mode (TSEM) for imaging and measurement of size and size distribution of spherical nanoparticles.

    PubMed

    Hodoroaba, Vasile-Dan; Motzkus, Charles; Macé, Tatiana; Vaslin-Reimann, Sophie

    2014-04-01

    The analytical performance of high-resolution scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) for accurate determination of the size, size distribution, qualitative elemental analysis of nanoparticles (NPs) was systematically investigated. It is demonstrated how powerful high-resolution SEM is by using both mono- and bi-modal distributions of SiO2 airborne NPs collected on appropriate substrates after their generation from colloidal suspension. The transmission mode of the SEM (TSEM) is systematically employed for NPs prepared on thin film substrates such as transmission electron microscopy grids. Measurements in the transmission mode were performed by using a "single-unit" TSEM transmission setup as manufactured and patented by Zeiss. This alternative to the "conventional" STEM detector consists of a special sample holder that is used in conjunction with the in-place Everhart-Thornley detector. In addition, the EDX capabilities for imaging NPs, highlighting the promising potential with respect to exploitation of the sensitivity of the new large area silicon drift detector energy dispersive X-ray spectrometers were also investigated. The work was carried out in the frame of a large prenormative VAMAS (Versailles Project on Advanced Materials and Standards) project, dedicated to finding appropriate methods and procedures for traceable characterization of NP size and size distribution.

  5. Atomic resolution imaging of YAlO3: Ce in the chromatic and spherical aberration corrected PICO electron microscope.

    PubMed

    Jin, Lei; Barthel, Juri; Jia, Chun-Lin; Urban, Knut W

    2017-01-31

    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 200kV. 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.

  6. Electron diffraction from free-standing, metal-coated transmission gratings

    NASA Astrophysics Data System (ADS)

    Gronniger, Glen; Barwick, Brett; Batelaan, Herman; Savas, Tim; Pritchard, Dave; Cronin, Alex

    2005-09-01

    Electron diffraction from a free-standing nanofabricated transmission grating was demonstrated, with energies ranging from 125 eV to 25 keV. Observation of 21 diffraction orders highlights the quality of the gratings. The image charge potential due to one electron was measured by rotating the grating. These gratings may pave the way to low-energy electron interferometry.

  7. Electronic transmission and switch effect in kappa-component Fibonacci nanowires.

    PubMed

    Li, Jia; Zhang, Ruili; Li, De; Peng, Ruwen; Wang, Mu

    2010-11-01

    We present the electronic transport in the k-component Fibonacci (KCF) nanowires, in which kappa different incommensurate intervals are arranged according to a substitution rule. For the KCF nanowires with an identical kappa, by increasing the length of the nanowire, the minima in transmission extend gradually into the band gap over which the transmission is blocked. Meanwhile more transmission peaks appear. For finite KCF nanowire, by increasing the number of different incommensurate intervals kappa, the width of electronic band gap is enlarged. Moreover, when the value of kappa is sufficiently large, the transmission is shut off, except at a few resonant energies. These properties make it possible to use the KCF nanowires as switching devices. Furthermore, a dimensional spectrum of singularities associated with the transmission spectrum demonstrates that the electronic propagation in the KCF nanowire shows multifractality. These investigations open a unique way to control quantum transport in nanodevices.

  8. High-resolution electron microscopy in spin pumping NiFe/Pt interfaces

    SciTech Connect

    Ley Domínguez, D. Sáenz-Hernández, R. J.; Faudoa Arzate, A.; Arteaga Duran, A. I.; Ornelas Gutiérrez, C. E.; Solís Canto, O.; Botello-Zubiate, M. E.; Rivera-Gómez, F. J.; Matutes-Aquino, J. A.; Azevedo, A.; Silva, G. L. da; Rezende, S. M.

    2015-05-07

    In order to understand the effect of the interface on the spin pumping and magnetic proximity effects, high resolution transmission electron microscopy and ferromagnetic resonance (FMR) were used to analyze Py/Pt bilayer and Pt/Py/Pt trilayer systems. The samples were deposited by dc magnetron sputtering at room temperature on Si (001) substrates. The Py layer thickness was fixed at 12 nm in all the samples and the Pt thickness was varied in a range of 0–23 nm. A diffusion zone of approximately 8 nm was found in the Py/Pt interfaces and confirmed by energy dispersive X-ray microanalysis. The FMR measurements show an increase in the linewidth and a shift in the ferromagnetic resonance field, which reach saturation.

  9. APES: Acute Precipitating Electron Spectrometer -- A high time resolution monodirectional magnetic deflection electron spectrometer

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    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 × 100 mm), and there was a total of 50 discrete anodes under the MCP, each one 15 mm × 1.5 mm, with a 0.5 mm spacing between anodes. The target energy range of APES was 200 eV to 30 keV.

  10. Transmission electron microscopy and theoretical analysis of AuCu nanoparticles: atomic distribution and dynamic behavior.

    PubMed

    Ascencio, J A; Liu, H B; Pal, U; Medina, A; Wang, Z L

    2006-07-01

    Though the application of bimetallic nanoparticles is becoming increasingly important, the local atomistic structure of such alloyed particles, which is critical for tailoring their properties, is not yet very clearly understood. In this work, we present detailed study on the atomistic structure of Au-Cu nanoparticles so as to determine their most stable configurations and the conditions for obtaining clusters of different structural variants. The dynamic behavior of these nanoparticles upon local heating is investigated. AuCu nanoparticles are characterized by high resolution transmission electron microscopy (HRTEM) and energy filtering elemental composition mapping (EFECM), which allowed us to study the internal structure and the elemental distribution in the particles. Quantum mechanical approaches and classic molecular dynamics methods are applied to model the structure and to determine the lowest energy configurations, the corresponding electronic structures, and understand structural transition of clusters upon heating, supported by experimental evidences. Our theoretical results demonstrate only the core/shell bimetallic structure have negative heat of formation, both for decahedra and octahedral, and energetically favoring core/shell structure is with Au covering the core of Cu, whose reverse core/shell structure is not stable and may transform back at a certain temperature. Experimental evidences corroborate these structures and their structural changes upon heating, demonstrating the possibility to manipulate the structure of such bimetallic nanoparticles using extra stimulating energy, which is in accordance with the calculated coherence energy proportions between the different configurations.

  11. A Simple Transmission Electron Microscopy Method for Fast Thickness Characterization of Suspended Graphene and Graphite Flakes.

    PubMed

    Rubino, Stefano; Akhtar, Sultan; Leifer, Klaus

    2016-02-01

    We present a simple, fast method for thickness characterization of suspended graphene/graphite flakes that is based on transmission electron microscopy (TEM). We derive an analytical expression for the intensity of the transmitted electron beam I 0(t), as a function of the specimen thickness t (t<λ; where λ is the absorption constant for graphite). We show that in thin graphite crystals the transmitted intensity is a linear function of t. Furthermore, high-resolution (HR) TEM simulations are performed to obtain λ for a 001 zone axis orientation, in a two-beam case and in a low symmetry orientation. Subsequently, HR (used to determine t) and bright-field (to measure I 0(0) and I 0(t)) images were acquired to experimentally determine λ. The experimental value measured in low symmetry orientation matches the calculated value (i.e., λ=225±9 nm). The simulations also show that the linear approximation is valid up to a sample thickness of 3-4 nm regardless of the orientation and up to several ten nanometers for a low symmetry orientation. When compared with standard techniques for thickness determination of graphene/graphite, the method we propose has the advantage of being simple and fast, requiring only the acquisition of bright-field images.

  12. Scanning and transmission electron microscopy for evaluation of order/disorder in bone structure.

    PubMed

    Suvorova, Elena I; Petrenko, Pavel P; Buffat, Philippe A

    2007-01-01

    A comparative characterization of the structure of normal and abnormal (osteoporotic) human lumbar and thoracic vertebrae samples was carried out to reveal the type of possible disorder. Samples from the bone fragments extracted during the surgery due to vertebra fractures were examined by scanning electron microscopy (SEM), conventional and high resolution transmission electron microscopy (TEM and HRTEM), and X-ray energy dispersive spectroscopy (EDS). Contrary to what might be expected in accordance with possible processes of dissolution, formation and remineralization of hard tissues, no changes in phase composition of mineral part, crystal sizes (length, width, and thickness), and arrangement of crystals on collagen fibers were detected in abnormal bones compared to the normal ones. The following sizes were determined by HRTEM for all bone samples:

  13. In Situ Transmission Electron Microscopy of Lead Dendrites and Lead Ions in Aqueous Solution

    PubMed Central

    White, Edward R.; Singer, Scott B.; Augustyn, Veronica; Hubbard, William A.; Mecklenburg, Matthew; Dunn, Bruce; Regan, Brian C.

    2012-01-01

    An ideal technique for observing nanoscale assembly would provide atomic-resolution images of both the products and the reactants in real time. Using a transmission electron microscope (TEM) we image in situ the electrochemical deposition of lead from an aqueous solution of lead(II) nitrate. Both the lead deposits and the local Pb2+ concentration can be visualized. Depending on the rate of potential change and the potential history, lead deposits on the cathode in a structurally compact layer or in dendrites. In both cases the deposits can be removed and the process repeated. Asperities that persist through many plating and stripping cycles consistently nucleate larger dendrites. Quantitative digital image analysis reveals excellent correlation between changes in the Pb2+ concentration, the rate of lead deposition, and the current passed by the electrochemical cell. Real-time electron microscopy of dendritic growth dynamics and the associated local ionic concentrations can provide new insight into the functional electrochemistry of batteries and related energy storage technologies. PMID:22702348

  14. Lithium electrodeposition dynamics in aprotic electrolyte observed in situ via transmission electron microscopy

    DOE PAGES

    Leenheer, Andrew Jay; Jungjohann, Katherine Leigh; Zavadil, Kevin Robert; ...

    2015-03-18

    Electrodeposited metallic lithium is an ideal negative battery electrode, but nonuniform microstructure evolution during cycling leads to degradation and safety issues. A better understanding of the Li plating and stripping processes is needed to enable practical Li-metal batteries. Here we use a custom microfabricated, sealed liquid cell for in situ scanning transmission electron microscopy (STEM) to image the first few cycles of lithium electrodeposition/dissolution in liquid aprotic electrolyte at submicron resolution. Cycling at current densities from 1 to 25 mA/cm2 leads to variations in grain structure, with higher current densities giving a more needle-like, higher surface area deposit. The effectmore » of the electron beam was explored, and it was found that, even with minimal beam exposure, beam-induced surface film formation could alter the Li microstructure. The electrochemical dissolution was seen to initiate from isolated points on grains rather than uniformly across the Li surface, due to the stabilizing solid electrolyte interphase surface film. As a result, we discuss the implications for operando STEM liquid-cell imaging and Li-battery applications.« less

  15. Small bimetallic (Pt/Pd) particles by biosynthesis: transmission electron microscopy and quantum mechanical analysis.

    PubMed

    Herrera-Becerra, R; Zorrilla, C; Canizal, G; Schabes-Retchkiman, P S; Liu, H B; Tavera-Davila, L; Rosano-Ortega, G; Rendon, L; Ascencio, J A

    2009-03-01

    Bimetallic Pd/Pt nanoparticles were synthesized by bio-reduction method. The structural characterizations were performed by high resolution transmission electron microscope and energy dispersive spectroscopy. The size distribution, shapes, structures and elemental distribution were studied for the synthesized samples. Molecular simulation methods based on quantum mechanics have been applied to acquire the further information on their structural stability, electronic properties etc. The results show that the particle size for the pH = 4 was bimodal with an average particle size of 3.2 nm and a variance of 1.8 nm. While for pH is 7 the average is 3.9 nm about the variance increase up to 3.7 nm, and larger particles can be found. By the HREM micrographs, it is identified fcc-like clusters with a few planar defects, which may be pure Pd or Pt, or bimetallic Pd/Pt. Theoretically the most stable configuration corresponds to the Pd18Pt37 eutectic-like structure, which implies a cluster in cluster form.

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

    PubMed

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

    2011-12-01

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

  17. Xenon Implantation in Nanodiamonds: In Situ Transmission Electron Microscopy Study and Molecular Dynamics Simulations

    NASA Astrophysics Data System (ADS)

    Shiryaev, A. A.; Hinks, J.; Marks, N.; Greaves, G.; Donnelly, S.; Fisenko, A. V.; Kiwi, M.

    2016-08-01

    We present results of the first investigation of the Xe implantation process into nanodiamonds of various sizes studied in situ in transmission electron microscope (TEM), complemented by advanced molecular dynamics simulations.

  18. 45 CFR Appendix C to Part 1355 - Electronic Data Transmission Format

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... DEVELOPMENT SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES THE ADMINISTRATION ON CHILDREN, YOUTH AND FAMILIES, FOSTER CARE MAINTENANCE PAYMENTS, ADOPTION ASSISTANCE, AND CHILD AND FAMILY SERVICES GENERAL Pt... for Children and Families (ACF). Regardless of the electronic data transmission methodology...

  19. 7 CFR 400.209 - Electronic transmission and receiving system.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... store actuarial data electronically via telecommunications utilizing 3780 protocol and utilizing a BELL... the data elements in the Summary of Protection; (5) Transmit crop insurance data electronically, via... acknowledgements, error messages, and other data via 3780 protocol utilizing a BELL 208B or compatible modem...

  20. Coupling Automated Electron Backscatter Diffraction with Transmission Electron and Atomic Force Microscopies

    SciTech Connect

    Schwartz, A.J.; Kumar, M.; Bedrossian, P.J.; King, W.E.

    2000-01-26

    Grain boundary network engineering is an emerging field that encompasses the concept that modifications to conventional thermomechanical processing can result in improved properties through the disruption of the random grain boundary network. Various researchers have reported a correlation between the grain boundary character distribution (defined as the fractions of special and random grain boundaries) and dramatic improvements in properties such as corrosion and stress corrosion cracking, creep, etc. While much early work in the field emphasized property improvements, the opportunity now exists to elucidate the underlying materials science of grain boundary network engineering. Recent investigations at LLNL have coupled automated electron backscatter diffraction (EBSD) with transmission electron microscopy (TEM) and atomic force microscopy (AFM) to elucidate these fundamental mechanisms. This investigation provides evidence that grain boundary network engineering and the formation of annealing twins disrupt the connectivity of the random grain boundary network and is likely responsible for the experimentally observed improvement in properties. This work illustrates that coupling of automated EBSD with other microstructural probes such as TEM and AFM provides data of greater value than any single technique in isolation. The coupled techniques have been applied to aid in understanding the underlying mechanisms of grain boundary network engineering and the corrosion properties of individual boundaries.

  1. Measurements of the UV and VUV transmission of optical materials during high energy electron irradiation

    NASA Technical Reports Server (NTRS)

    Palma, G. E.

    1972-01-01

    An experimental program was conducted in which the optical transmission of several transparent materials was measured during high energy electron irradiation. These experiments were conducted using the Dynamitron electron accelerator as a continuous source of 1.5 MeV electrons and the LINAC electron accelerator as a pulsed source of 5-7 MeV electrons. The experimental program consisted of three major portions. The first portion, the optical transmission of fused silica, BeO, MgF2, and LiF was measured at vacuum ultraviolet wavelengths in the range 1550-2000 A during ambient temperature, 1.5 MeV electron irradiation at ionizing dose rates to 0.5 Mrad/sec. In the second portion of the program, the optical transmission of fused silica and BeO was measured in the range 2000-3000 A during high dose rate, elevated temperature 1.5 MeV electron irradiation. In particular, accurate measurements of the optical transmission were made at ionizing dose rates as high as 10 Mrad/sec. In the final portion of the program, the optical transmission of fused silica and BeO was measured in the wavelength range 2000-3000 A during pulsed 5 and 7 MeV electron irradiation from the LINAC accelerator. The maximum time averaged ionizing dose rate was limited to 0.75 Mrad/sec due to accelerator limitations.

  2. Deciphering the physics and chemistry of perovskites with transmission electron microscopy.

    PubMed

    Polking, Mark J

    2016-03-28

    Perovskite oxides exhibit rich structural complexity and a broad range of functional properties, including ferroelectricity, ferromagnetism, and superconductivity. The development of aberration correction for the transmission electron microscope and concurrent progress in electron spectroscopy, electron holography, and other techniques has fueled rapid progress in the understanding of the physics and chemistry of these materials. New techniques based on the transmission electron microscope are first surveyed, and the applications of these techniques for the study of the structure, chemistry, electrostatics, and dynamics of perovskite oxides are then explored in detail, with a particular focus on ferroelectric materials.

  3. Deciphering the physics and chemistry of perovskites with transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Polking, Mark J.

    2016-03-01

    Perovskite oxides exhibit rich structural complexity and a broad range of functional properties, including ferroelectricity, ferromagnetism, and superconductivity. The development of aberration correction for the transmission electron microscope and concurrent progress in electron spectroscopy, electron holography, and other techniques has fueled rapid progress in the understanding of the physics and chemistry of these materials. New techniques based on the transmission electron microscope are first surveyed, and the applications of these techniques for the study of the structure, chemistry, electrostatics, and dynamics of perovskite oxides are then explored in detail, with a particular focus on ferroelectric materials.

  4. High Resolution Inelastic Electron Scattering from LEAD-208.

    NASA Astrophysics Data System (ADS)

    Connelly, James Patrick

    Inclusive electron scattering differential cross sections from ^{208}Pb have been measured with energy resolutions better than 20 keV for over 120 discrete states with excitation energies less than 7.3 MeV. The momentum-transfer dependence of these cross sections has been mapped over a range of 0.5 to 2.8 fm^{-1} in the forward direction and 1.0 to 2.9 fm^{ -1} in the backward scattering direction. Over fifty excitations have been analyzed in the Distorted Wave Born Approximation to yield transition charge, current and magnetization densities. The nuclear structure of discrete excitations are interpreted in the framework of 1p-1h transition. The nuclear structure of levels in the excitation region below 4.8 MeV is studied in detail. Above 4.8 MeV, multiplets from single particle-hole configurations coupling to high spin states (J >=q 7) are investigated. Experimental transition densities are compared to Tamm-Dancoff calculations from a correlated ground state.

  5. Electronic Master Monitor and Advisory Display System, Data Transmission Study.

    DTIC Science & Technology

    1980-08-01

    Master Monitor and Advisory Display system (EMMADS). By contrac- tual requirement the EMMADS demonstration hardware will use a dual redundant MIL- STD -1553B...data multiplexing bus, the minimum requirement for EMMADS data transmission rate is 74.2 Kilobits per second. The MIL- STD -1553 Bus is specified to...as the French military standard, the counterpart of US MIL- STD -1553. DSDBS is developed for the sole purpose of minimizing the hardware with

  6. Reconstruction of nuclear quadrupole interaction in (In,Ga)As/GaAs quantum dots observed by transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Sokolov, P. S.; Petrov, M. Yu.; Mehrtens, T.; Müller-Caspary, K.; Rosenauer, A.; Reuter, D.; Wieck, A. D.

    2016-01-01

    A microscopic study of the individual annealed (In,Ga)As/GaAs quantum dots is done by means of high-resolution transmission electron microscopy. The Cauchy-Green strain-tensor component distribution and the chemical composition of the (In,Ga)As alloy are extracted from the microscopy images. The image processing allows for the reconstruction of the strain-induced electric-field gradients at the individual atomic columns extracting thereby the magnitude and asymmetry parameter of the nuclear quadrupole interaction. Nuclear magnetic resonance absorption spectra are analyzed for parallel and transverse mutual orientations of the electric-field gradient and a static magnetic field.

  7. Transmissive x-ray beam position monitors with submicron position- and submillisecond time resolution.

    PubMed

    Fuchs, Martin R; Holldack, Karsten; Bullough, Mark; Walsh, Susanne; Wilburn, Colin; Erko, Alexei; Schäfers, Franz; Mueller, Uwe

    2008-06-01

    We present the development of fast transmissive center-of-mass x-ray beam position monitors with a large active area, based on a thinned position sensitive detector in both a duo- and a tetra-lateral variant. The detectors were tested at BESSY beamlines BL14.1, KMC-1, and KMC-2 and yielded signal currents of up to 3 microA/100 mA ring current at 10 keV photon energy using the monochromatic focused beam of BL14.1. The active area sizes were 1 x 1 and 3 x 3 mm(2) for the duo-lateral and 5 x 5 mm(2) for the tetra-lateral devices, with the duo-lateral detectors currently being available in sizes from 1 x 1 to 10 x 10 mm(2) and thicknesses between 5 and 10 microm. The presented detectors' thicknesses were measured to be 5 and 8 microm with a corresponding transmission of up to 93% at 10 keV and 15% at 2.5 keV. Up to a detection bandwidth of 10 kHz, the monitors provide submicron position resolution. For lower detection bandwidths, the signal-to-noise reaches values of up to 6 x 10(4) at 10 Hz, corresponding to a position resolution of better than 50 nm for both detector sizes. As it stands, this monitor design approach promises to be a generic solution for automation of state-of-the-art crystal monochromator beamlines.

  8. High-resolution electron microscopy and electron energy-loss spectroscopy of giant palladium clusters

    NASA Astrophysics Data System (ADS)

    Oleshko, V.; Volkov, V.; Gijbels, R.; Jacob, W.; Vargaftik, M.; Moiseev, I.; van Tendeloo, G.

    1995-12-01

    Combined structural and chemical characterization of cationic polynuclear palladium coordination compounds Pd561L60(OAc)180, where L=1,10-phenantroline or 2,2'-bipyridine has been carried out by high-resolution electron microscopy (HREM) and analytical electron microscopy methods including electron energy-loss spectroscopy (EELS), zero-loss electron spectroscopic imaging, and energy-dispersive X-ray spectroscopy (EDX). The cell structure of the cluster matter with almost completely uniform metal core size distributions centered around 2.3 ±0.5 nm was observed. Zero-loss energy filtering allowed to improve the image contrast and resolution. HREM images showed that most of the palladium clusters had a cubo-octahedral shape. Some of them had a distorted icosahedron structure exhibiting multiple twinning. The selected-area electron diffraction patterns confirmed the face centered cubic structure with lattice parameter close to that of metallic palladium. The energy-loss spectra of the populations of clusters contained several bands, which could be assigned to the delayed Pd M4, 5-edge at 362 eV, the Pd M3-edge at 533 eV and the Pd M2-edge at 561 eV, the NK-edge at about 400 eV, the O K-edge at 532 eV overlapping with the Pd M3-edge and the carbon C K-edge at 284 eV. Background subtraction was applied to reveal the exact positions and fine structure of low intensity elemental peaks. EELS evaluations have been confirmed by EDX. The recorded series of the Pd M-edges and the N K-edge in the spectra of the giant palladium clusters obviously were related to Pd-Pd- and Pd-ligand bonding.

  9. Characterization of an HY-130 Steel Weldment by Transmission Electron Microscopy.

    DTIC Science & Technology

    1981-12-01

    A0A1IA 451 NAVAL POSTGRADUATE SCHOOL MONTEREY CA F/6 11/6 cHARACTERZXATION O AN NY-130 STEEL WELOMENT BY TRANSMISSION EL--ETC(U) UNLA D DEC 81 W N...17 19.8 THESIS S CHARACTERIZATION OF AN HY-130 STEEL WELDMENT BY TRANSMISSION ELECTRON MICROSCOPY by Wallace Michael Elger December 1981 0-. Thesis...REPORT & PERIOD COVERED Characterization of an HY-130 Steel Master’s Thesis; Weidment by Transmission Electron December 1981 Microscopy 6. PERFORMING

  10. Low-loss electron energy loss spectroscopy: An atomic-resolution complement to optical spectroscopies and application to graphene

    SciTech Connect

    Kapetanakis, Myron; Zhou, Wu; Oxley, Mark P.; Lee, Jaekwang; Prange, Micah P.; Pennycook, Stephen J.; Idrobo Tapia, Juan Carlos; Pantelides, Sokrates T.

    2015-09-25

    Photon-based spectroscopies have played a central role in exploring the electronic properties of crystalline solids and thin films. They are a powerful tool for probing the electronic properties of nanostructures, but they are limited by lack of spatial resolution. On the other hand, electron-based spectroscopies, e.g., electron energy loss spectroscopy (EELS), are now capable of subangstrom spatial resolution. Core-loss EELS, a spatially resolved analog of x-ray absorption, has been used extensively in the study of inhomogeneous complex systems. In this paper, we demonstrate that low-loss EELS in an aberration-corrected scanning transmission electron microscope, which probes low-energy excitations, combined with a theoretical framework for simulating and analyzing the spectra, is a powerful tool to probe low-energy electron excitations with atomic-scale resolution. The theoretical component of the method combines density functional theory–based calculations of the excitations with dynamical scattering theory for the electron beam. We apply the method to monolayer graphene in order to demonstrate that atomic-scale contrast is inherent in low-loss EELS even in a perfectly periodic structure. The method is a complement to optical spectroscopy as it probes transitions entailing momentum transfer. The theoretical analysis identifies the spatial and orbital origins of excitations, holding the promise of ultimately becoming a powerful probe of the structure and electronic properties of individual point and extended defects in both crystals and inhomogeneous complex nanostructures. The method can be extended to probe magnetic and vibrational properties with atomic resolution.

  11. Low-loss electron energy loss spectroscopy: An atomic-resolution complement to optical spectroscopies and application to graphene

    DOE PAGES

    Kapetanakis, Myron; Zhou, Wu; Oxley, Mark P.; ...

    2015-09-25

    Photon-based spectroscopies have played a central role in exploring the electronic properties of crystalline solids and thin films. They are a powerful tool for probing the electronic properties of nanostructures, but they are limited by lack of spatial resolution. On the other hand, electron-based spectroscopies, e.g., electron energy loss spectroscopy (EELS), are now capable of subangstrom spatial resolution. Core-loss EELS, a spatially resolved analog of x-ray absorption, has been used extensively in the study of inhomogeneous complex systems. In this paper, we demonstrate that low-loss EELS in an aberration-corrected scanning transmission electron microscope, which probes low-energy excitations, combined with amore » theoretical framework for simulating and analyzing the spectra, is a powerful tool to probe low-energy electron excitations with atomic-scale resolution. The theoretical component of the method combines density functional theory–based calculations of the excitations with dynamical scattering theory for the electron beam. We apply the method to monolayer graphene in order to demonstrate that atomic-scale contrast is inherent in low-loss EELS even in a perfectly periodic structure. The method is a complement to optical spectroscopy as it probes transitions entailing momentum transfer. The theoretical analysis identifies the spatial and orbital origins of excitations, holding the promise of ultimately becoming a powerful probe of the structure and electronic properties of individual point and extended defects in both crystals and inhomogeneous complex nanostructures. The method can be extended to probe magnetic and vibrational properties with atomic resolution.« less

  12. Light transmission spectroscopy in real time: a high-resolution nanoparticle analysis instrument.

    PubMed

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

    2017-03-01

    This paper describes light transmission spectroscopy (LTS), a technique for eliminating spectral noise and systematic effects in real-time spectroscopic measurements. In our work, we combine LTS with spectral inversion for the purpose of nanoparticle analysis. This work employs a wideband multi-wavelength light source and grating spectrometers coupled to CCD detectors. The light source ranges from 210 to 2000 nm, the wavelength-dependent light detection system ranges from 200 to 1100 nm with ≤1  nm resolution, and the nanoparticle diameters range from 1 to 3000 nm. The nanoparticles are suspended in pure water or water-based buffer solutions. For testing and calibration purposes, results are presented for nanoparticles composed of polystyrene and gold. Mie theory is used to model the total extinction cross section, and spectral inversion is employed to obtain quantitative particle size distributions, from which information on the size, shape, and number of nanoparticles can be derived. Discussed are the precision, accuracy, resolution, and sensitivity of our results. The LTS technique is quite versatile and can be applied to spectroscopic investigations where wideband, accurate, low-noise, real-time spectra are desired.

  13. X-ray Interferometry with Transmissive Beam Combiners for Ultra-High Angular Resolution Astronomy

    NASA Technical Reports Server (NTRS)

    Skinner, G. K.; Krismanic, John F.

    2009-01-01

    Abstract Interferometry provides one of the possible routes to ultra-high angular resolution for X-ray and gamma-ray astronomy. Sub-micro-arc-second angular resolution, necessary to achieve objectives such as imaging the regions around the event horizon of a super-massive black hole at the center of an active galaxy, can be achieved if beams from parts of the incoming wavefront separated by 100s of meters can be stably and accurately brought together at small angles. One way of achieving this is by using grazing incidence mirrors. We here investigate an alternative approach in which the beams are recombined by optical elements working in transmission. It is shown that the use of diffractive elements is a particularly attractive option. We report experimental results from a simple 2-beam interferometer using a low-cost commercially available profiled film as the diffractive elements. A rotationally symmetric filled (or mostly filled) aperture variant of such an interferometer, equivalent to an X-ray axicon, is shown to offer a much wider bandpass than either a Phase Fresnel Lens (PFL) or a PFL with a refractive lens in an achromatic pair. Simulations of an example system are presented.

  14. Interpreting electron transmission spectroscopy and negative ion mass spectrometry data using a spherical potential well model

    SciTech Connect

    Asfandiarov, N. L. Nafikova, E. P.; Pshenichnyuk, S. A.

    2007-03-15

    Experimental data obtained using electron transmission spectroscopy and negative ion mass spectrometry based on resonance electron capture are interpreted within the framework of a spherical potential well model in application to a series of chloro-and bromoalkane molecules. Allowance for the scattering of a single partial p-wave of the incoming electron makes possible (i) reproduction of the ratio of a resonance peak width to the electron energy observed in the electron transmission spectra and (ii) establishment of a relation between the total cross section of electron scattering on a molecule and the dissociative electron attachment cross section. The proposed model offers a radical simplification of the approach developed previously based on the Fashbach-Fano resonance theory.

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

    PubMed

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

    2010-01-01

    Charge-coupled devices (CCD) are nowadays commonly utilized in transmission electron microscopy (TEM) for applications in life sciences. Direct access to digitized images has revolutionized the use of electron microscopy, sparking developments such as automated collection of tomographic data, focal series, random conical tilt pairs and ultralarge single-particle data sets. Nevertheless, for ultrahigh-resolution work photographic plates are often still preferred. In the ideal case, the quality of the recorded image of a vitrified biological sample would solely be determined by the counting statistics of the limited electron dose the sample can withstand before beam-induced alterations dominate. Unfortunately, the image is degraded by the non-ideal point-spread function of the detector, as a result of a scintillator coupled by fibre optics to a CCD, and the addition of several inherent noise components. Different detector manufacturers provide different types of figures of merit when advertising the quality of their detector. It is hard for most laboratories to verify whether all of the anticipated specifications are met. In this report, a set of algorithms is presented to characterize on-axis slow-scan large-area CCD-based TEM detectors. These tools have been added to a publicly available image-processing toolbox for MATLAB. Three in-house CCD cameras were carefully characterized, yielding, among others, statistics for hot and bad pixels, the modulation transfer function, the conversion factor, the effective gain and the detective quantum efficiency. These statistics will aid data-collection strategy programs and provide prior information for quantitative imaging. The relative performance of the characterized detectors is discussed and a comparison is made with similar detectors that are used in the field of X-ray crystallography.

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

    NASA Astrophysics Data System (ADS)

    Reuter, Matthew; Harrison, Robert

    2014-03-01

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

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

    PubMed Central

    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

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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.

  19. Quantum Interference and Ballistic Transmission in Nanotube Electron Waveguides

    SciTech Connect

    Kong, Jing; Yenilmez, Erhan; Tombler, Thomas W.; Kim, Woong; Dai, Hongjie; Laughlin, Robert B.; Liu, Lei; Jayanthi, C. S.; Wu, S. Y.

    2001-09-03

    The electron transport properties of well-contacted individual single-walled carbon nanotubes are investigated in the ballistic regime. Phase coherent transport and electron interference manifest as conductance fluctuations as a function of Fermi energy. Resonance with standing waves in finite-length tubes and localized states due to imperfections are observed for various Fermi energies. Two units of quantum conductance 2G{sub 0}=4e{sup 2}/h are measured for the first time, corresponding to the maximum conductance limit for ballistic transport in two channels of a nanotube.

  20. Low impact to fixed cell processing aiming transmission electron microscopy

    PubMed Central

    Barth, Ortrud Monika; da Silva, Marcos Alexandre Nunes; Barreto-Vieira, Debora Ferreira

    2016-01-01

    In cell culture, cell structures suffer strong impact due to centrifugation during processing for electron microscope observation. In order to minimise this effect, a new protocol was successfully developed. Using conventional reagents and equipments, it took over one week, but cell compression was reduced to none or the lowest deformation possible. PMID:27276186

  1. Free electron lasers for transmission of energy in space

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

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

  2. 21 CFR 1311.05 - Standards for technologies for electronic transmission of orders.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 9 2012-04-01 2012-04-01 false Standards for technologies for electronic transmission of orders. 1311.05 Section 1311.05 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE REQUIREMENTS FOR ELECTRONIC ORDERS AND PRESCRIPTIONS General § 1311.05 Standards for...

  3. 21 CFR 1311.05 - Standards for technologies for electronic transmission of orders.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 9 2011-04-01 2011-04-01 false Standards for technologies for electronic transmission of orders. 1311.05 Section 1311.05 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE REQUIREMENTS FOR ELECTRONIC ORDERS AND PRESCRIPTIONS General § 1311.05 Standards for...

  4. 21 CFR 1311.05 - Standards for technologies for electronic transmission of orders.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 9 2013-04-01 2013-04-01 false Standards for technologies for electronic transmission of orders. 1311.05 Section 1311.05 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE REQUIREMENTS FOR ELECTRONIC ORDERS AND PRESCRIPTIONS General § 1311.05 Standards for...

  5. 77 FR 50932 - Electronic Transmission of Customs Data-Outbound International Letter-Post Items

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-23

    ... 20 Electronic Transmission of Customs Data--Outbound International Letter-Post Items AGENCY: Postal... Standards of the United States Postal Service, International Mail Manual (IMM ) to require that customs data be electronically transmitted for international letter-post mailpieces bearing a customs...

  6. Gold Induced SILICON(111) Surface Reconstructions Studied by Ultrahigh Vacuum Transmission Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Plass, Richard Anton

    Due to its growing scientific and technical importance in semiconductor metallization, the Au on Si(111) system has recently drawn the attention of many researchers. Therefore, the atomic structures of two gold induced Si(111) surface reconstructions were determined using ultrahigh vacuum transmission electron microscopy. The Si(111)-(5 x 2) Au atomic structure was determined using a combination of off-zone HREM imaging, "heavy-atom holography", and chi^2 electron diffraction refinement. It contains two rows of gold atoms between expanded surface arrangements of silicon atoms. Si(111) -(5 x 2) Au passivates the surface to oxygen attack and room temperature gold deposition onto it indicates surface diffusion is important in its disordering. Transmission electron diffraction data of the Si(111)-(surd 3 x surd3)R30 ^circAu surface support the missing top layer twisted trimer model of this surface in which gold and silicon atoms in the top two layers form rotated like-atom trimers. This gold-silicon structure is quite similar to part of the Si(111)-(5 x 2) Au structure. The degree of trimer rotation and the interatomic spacings of the Si(111)-(surd3 x surd3)R30 ^circAu structure vary significantly with the sharpness of the structure's diffraction spots. These variations and large fitted Debye Waller term values indicate substantial static disorder is present. Evidence of subsurface displacements and charge transfer was also found. The presence of gold trimers is confirmed by the local symmetry seen in high resolution micrographs, which also show surface domain morphology differences between diffuse and sharp diffraction spot regions. Based on these images, models for the Si(111)-(surd3 x surd3)R30 ^circAu domain walls are proposed. Room temperature gold deposition onto the Si(111) -(surd3timessurd3)R30 ^circAu surface shows that higher order surface diffracted beams decay more quickly with coverage than lower order beams. Direct phasing analysis of this result

  7. An inexpensive approach for bright-field and dark-field imaging by scanning transmission electron microscopy in scanning electron microscopy.

    PubMed

    Patel, Binay; Watanabe, Masashi

    2014-02-01

    Scanning transmission electron microscopy in scanning electron microscopy (STEM-in-SEM) is a convenient technique for soft materials characterization. Various specimen-holder geometries and detector arrangements have been used for bright-field (BF) STEM-in-SEM imaging. In this study, to further the characterization potential of STEM-IN-SEM, a new specimen holder has been developed to facilitate direct detection of BF signals and indirect detection of dark-field (DF) signals without the need for substantial instrument modification. DF imaging is conducted with the use of a gold (Au)-coated copper (Cu) plate attached to the specimen holder which directs highly scattered transmitted electrons to an off-axis yttrium-aluminum-garnet (YAG) detector. A hole in the copper plate allows for BF imaging with a transmission electron (TE) detector. The inclusion of an Au-coated Cu plate enhanced DF signal intensity. Experiments validating the acquisition of true DF signals revealed that atomic number (Z) contrast may be achieved for materials with large lattice spacing. However, materials with small lattice spacing still exhibit diffraction contrast effects in this approach. The calculated theoretical fine probe size is 1.8 nm. At 30 kV, in this indirect approach, DF spatial resolution is limited to 3.2 nm as confirmed experimentally.

  8. Development of large area, pico-second resolution photo-detectors and associated readout electronics

    SciTech Connect

    Grabas, H.; Oberla, E.; Attenkoffer, K.; Bogdan, M.; Frisch, H. J.; Genat, J. F.; May, E. N.; Varner, G. S.; Wetstein, M.

    2011-07-01

    The Large Area Pico-second Photo-detectors described in this contribution incorporate a photo-cathode and a borosilicate glass capillary Micro-Channel Plate (MCP) pair functionalized by atomic layer deposition (ALD) of separate resistive and electron secondary emitters materials. They may be used for biomedical imaging purposes, a remarkable opportunity to apply technologies developed in HEP having the potential to make major advances in the medical world, in particular for Positron Emission Tomography (PET). If daisy-chained and coupled to fast transmission lines read at both ends, they could be implemented in very large dimensions. Initial testing with matched pairs of small glass capillary test has demonstrated gains of the order of 105 to 106. Compared to other fast imaging devices, these photo-detectors are expected to provide timing resolutions in the 10-100 ps range, and two-dimension position in the sub-millimeter range. A 6-channel readout ASIC has been designed in 130 nm CMOS technology and tested. As a result, fast analog sampling up to 17 GS/s has been obtained, the intrinsic analog bandwidth being presently under evaluation. The digitization in parallel of several cells in two microseconds allows getting off-chip digital data read at a maximum rate of 40 MHz. Digital Signal Processing of the sampled waveforms is expected achieving the timing and space resolutions obtained with digital oscilloscopes. (authors)

  9. A Feasibility Study of 50 nm Resolution with Low Energy Electron Beam Proximity Projection Lithography

    NASA Astrophysics Data System (ADS)

    Yoshizawa, Masaki; Savas, T. A.

    2002-01-01

    Patterns of 50 nm lines and spaces were demonstrated by low energy electron beam proximity lithography using 47-nm-thick poly methyl methacrylate (PMMA) and stencil masks fabricated by achromatic interference lithography (AIL). The result indicates the validity of the resolution analysis previously reported and the resolution capabilities of low energy electron beam proximity projection lithography (LEEPL) as a 50 nm node technology.

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

    NASA Astrophysics Data System (ADS)

    Haas, Oliver Sebastian; Boine-Frankenheim, Oliver; Petrov, Fedor

    2013-11-01

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

  11. Aberration Corrected Scanning Transmission Electron Microscopy of (Ca , Sr)Fe2O5 Brownmillerite superlattices

    NASA Astrophysics Data System (ADS)

    Mukherjee, Debangshu; Stone, Greg; Moon, Eun Ju; Young, Joshua; Gopalan, Venkatraman; Rondinelli, James; May, Steven; Alem, Nasim

    The brownmillerite phase A2B2O5 consists of ordered oxygen vacancies in alternate perovskite layers forming chiral tetrahedral chains. The handedness of these tetrahedral chains control the polarization of the structure. The current study focuses on 1-1 brownmillerite superlattices grown on a SrTiO3 substrates using molecular beam epitaxy. The B-site in this structure is iron throughout the superlattice film, while the A-site alternates between calcium and strontium in the superlattice layers. In this study, we use atomic resolution aberration corrected scanning transmission electron microscopy (STEM) to investigate the structure and chemistry of the film-substrate interface as well as the chemical structure of the superlattice. Atom positions are determined to measure displacement vectors of A-site cations in the superlattice structure. D.M., G.A.S., V.G. and N.A. were supported by the National Science Foundation under Grant No. DMR-1420620. E.J.M. and S.J.M. were supported by the National Science Foundation under Grant No. DMR-1151649.

  12. High-speed nanoscale characterization of dewetting via dynamic transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Hihath, Sahar; Santala, Melissa K.; Campbell, Geoffrey; van Benthem, Klaus

    2016-08-01

    The dewetting of thin films can occur in either the solid or the liquid state for which different mass transport mechanisms are expected to control morphological changes. Traditionally, dewetting dynamics have been examined on time scales between several seconds to hours, and length scales ranging between nanometers and millimeters. The determination of mass transport mechanisms on the nanoscale, however, requires nanoscale spatial resolution and much shorter time scales. This study reports the high-speed observation of dewetting phenomena for kinetically constrained Ni thin films on crystalline SrTiO3 substrates. Movie-mode Dynamic Transmission Electron Microscopy (DTEM) was used for high-speed image acquisition during thin film dewetting at different temperatures. DTEM imaging confirmed that the initial stages of film agglomeration include edge retraction, hole formation, and growth. Finite element modeling was used to simulate temperature distributions within the DTEM samples after laser irradiation with different energies. For pulsed laser irradiation at 18 μJ, experimentally observed hole growth suggests that Marangoni flow dominates hole formation in the liquid nickel film. After irradiation with 13.8 μJ, however, the observations suggest that dewetting was initiated by nucleation of voids followed by hole growth through solid-state surface diffusion.

  13. TRANSMISSION ELECTRON MICROSCOPY OF Al-RICH SILICATE STARDUST FROM ASYMPTOTIC GIANT BRANCH STARS

    SciTech Connect

    Vollmer, Christian; Hoppe, Peter; Brenker, Frank E.

    2013-05-20

    We report on transmission electron microscopy (TEM) investigations of two mineralogically unusual stardust silicates to constrain their circumstellar condensation conditions. Both grains were identified by high spatial resolution nano secondary ion mass spectrometry (NanoSIMS) in the Acfer 094 meteorite, one of the most pristine carbonaceous chondrites available for study. One grain is a highly crystalline, highly refractory (Fe content < 0.5 at%), structurally undisturbed orthopyroxene (MgSiO{sub 3}) with an unusually high Al content (1.8 {+-} 0.5 at%). This is the first TEM documentation of a single crystal pyroxene within the complete stardust silicate data set. We interpret the microstructure and chemistry of this grain as being a direct condensate from a gas of locally non-solar composition (i.e., with a higher-than-solar Al content and most likely also a lower-than-solar Mg/Si ratio) at (near)-equilibrium conditions. From the overabundance of crystalline olivine (six reported grains to date) compared to crystalline pyroxene (only documented as a single crystal in this work) we infer that formation of olivine over pyroxene is favored in circumstellar environments, in agreement with expectations from condensation theory and experiments. The second stardust silicate consists of an amorphous Ca-Si rich material which lacks any crystallinity based on TEM observations in which tiny (<20 nm) hibonite nanocrystallites are embedded. This complex assemblage therefore attests to the fast cooling and rapidly changing chemical environments under which dust grains in circumstellar shells form.

  14. Transmission Electron Microscopy of Al-rich Silicate Stardust from Asymptotic Giant Branch Stars

    NASA Astrophysics Data System (ADS)

    Vollmer, Christian; Hoppe, Peter; Brenker, Frank E.

    2013-05-01

    We report on transmission electron microscopy (TEM) investigations of two mineralogically unusual stardust silicates to constrain their circumstellar condensation conditions. Both grains were identified by high spatial resolution nano secondary ion mass spectrometry (NanoSIMS) in the Acfer 094 meteorite, one of the most pristine carbonaceous chondrites available for study. One grain is a highly crystalline, highly refractory (Fe content < 0.5 at%), structurally undisturbed orthopyroxene (MgSiO3) with an unusually high Al content (1.8 ± 0.5 at%). This is the first TEM documentation of a single crystal pyroxene within the complete stardust silicate data set. We interpret the microstructure and chemistry of this grain as being a direct condensate from a gas of locally non-solar composition (i.e., with a higher-than-solar Al content and most likely also a lower-than-solar Mg/Si ratio) at (near)-equilibrium conditions. From the overabundance of crystalline olivine (six reported grains to date) compared to crystalline pyroxene (only documented as a single crystal in this work) we infer that formation of olivine over pyroxene is favored in circumstellar environments, in agreement with expectations from condensation theory and experiments. The second stardust silicate consists of an amorphous Ca-Si rich material which lacks any crystallinity based on TEM observations in which tiny (<20 nm) hibonite nanocrystallites are embedded. This complex assemblage therefore attests to the fast cooling and rapidly changing chemical environments under which dust grains in circumstellar shells form.

  15. Visualizing non-equilibrium lithiation of spinel oxide via in situ transmission electron microscopy

    PubMed Central

    He, Kai; Zhang, Sen; Li, Jing; Yu, Xiqian; Meng, Qingping; Zhu, Yizhou; Hu, Enyuan; Sun, Ke; Yun, Hongseok; Yang, Xiao-Qing; Zhu, Yimei; Gan, Hong; Mo, Yifei; Stach, Eric A.; Murray, Christopher B.; Su, Dong

    2016-01-01

    Spinel transition metal oxides are important electrode materials for lithium-ion batteries, whose lithiation undergoes a two-step reaction, whereby intercalation and conversion occur in a sequential manner. These two reactions are known to have distinct reaction dynamics, but it is unclear how their kinetics affects the overall electrochemical response. Here we explore the lithiation of nanosized magnetite by employing a strain-sensitive, bright-field scanning transmission electron microscopy approach. This method allows direct, real-time, high-resolution visualization of how lithiation proceeds along specific reaction pathways. We find that the initial intercalation process follows a two-phase reaction sequence, whereas further lithiation leads to the coexistence of three distinct phases within single nanoparticles, which has not been previously reported to the best of our knowledge. We use phase-field theory to model and describe these non-equilibrium reaction pathways, and to directly correlate the observed phase evolution with the battery's discharge performance. PMID:27157119

  16. Multivariate statistics applications in scanning transmission electron microscopy X-ray spectrum imaging

    SciTech Connect

    Parish, Chad M

    2011-01-01

    A modern scanning transmission electron microscope (STEM) fitted with an energy dispersive X-ray spectroscopy (EDS) system can quickly and easily produce spectrum image (SI) datasets containing so much information (hundreds to thousands of megabytes) that they cannot be comprehensively interrogated by a human analyst. Therefore, advanced mathematical techniques are needed to glean materials science and engineering insight into the processing-structure-properties relationship of the examined material from the SI data. This review will discuss recent advances in the application of multivariate statistical analysis (MVSA) methods to STEM-EDS SI experiments. In particular, the fundamental mathematics of principal component analysis (PCA) and related methods are reviewed, and advanced methods such as multivariate curve resolution (MCR) are discussed. The applications of PCA and MCR-based techniques to solve difficult materials science problems, such as the analysis of a particle fully embedded in a matrix phase are discussed, as well as confounding effects such as rank deficiency that can confuse the results of MVSA computations. Possible future advances and areas in need of study are also mentioned.

  17. Transmission electron microscopy investigation of Ag diffusion mechanisms in β-SiC

    NASA Astrophysics Data System (ADS)

    Coward, Robert A.; Winkler, Christopher R.; Hanson, William A.; Jablonski, Michael L.; Taheri, Mitra L.

    2015-02-01

    β-Silicon carbide (β-SiC) acts as the main layer for metallic fission product retention in tristructural-isotropic (TRISO) fuel particles. It is critical to track these fission products in the β-SiC layer to provide a baseline understanding of safe fuel operation for next generation nuclear reactors. In this study, the microstructural evolution of the β-SiC layer is examined through the comparison of as-implanted and annealed samples up to 1600 °C using high resolution transmission electron microscopy (HRTEM). Faceted voids were observed in annealed samples but not in the as-implanted samples, suggesting the possibility that a void mediated fission product transport mechanism due to the change in microstructure of the β-SiC layer at elevated temperatures plays a role in the diffusion of metallic species through the β-SiC cladding layer. It should be noted, however, that Ag implantation at room temperature is not an ideal method to study Ag diffusion in TRISO fuel particles. Ultimately, Ag implantation should be performed above the critical temperature for which amorphization will not occur to better correlate to conditions in a Generation IV reactor and to see if void formation occurs.

  18. Applying an information transmission approach to extract valence electron information from reconstructed exit waves.

    PubMed

    Xu, Qiang; Zandbergen, Henny W; Van Dyck, Dirk

    2011-06-01

    The knowledge of the valence electron distribution is essential for understanding the properties of materials. However this information is difficult to obtain from HREM images because it is easily obscured by the large scattering contribution of core electrons and by the strong dynamical scattering process. In order to develop a sensitive method to extract the information of valence electrons, we have used an information transmission approach to describe the electron interaction with the object. The scattered electron wave is decomposed in a set of basic functions, which are the eigen functions of the Hamiltonian of the projected electrostatic object potential. Each basic function behaves as a communication channel that transfers the information of the object with its own transmission characteristic. By properly combining the components of the different channels, it is possible to design a scheme to extract the information of valence electron distribution from a series of exit waves. The method is described theoretically and demonstrated by means of computer simulations.

  19. Electronic control system for control of electronic electric shift apparatus for manual transmission

    SciTech Connect

    Tury, E.L.; Thoe, G.A.

    1989-04-18

    An electrical control apparatus is described for control of a manual transmission apparatus in a motor vehicle having a plurality of transmission states selected by the position of a shift select lever, the electrical control apparatus comprising: a first electric motor; means drive by the first electric motor and operative in response to energization of the first electric motor to move the shift select lever laterally between left, center, and right locations; a second electric motor; means driven by the second electric motor and operative in response to energization of the second electric motor to move the shift select lever longitudinally between forward, neutral, and rearward locations; operator input means operative to generate a desired transmission sate signal corresponding to manual operator input; a first transmission state sensing means for indicating the left, center, or right location of the shift select lever; a second transmission state sensing means for indicating the forward, neutral or rearward location of the shift select lever; and a logic control unit connected to the operator input means and the first and second transmission state sensing means for generation of a sequence of motor drive signals corresponding to the sequence of motions required for movement of the shift select lever from the present transmission state to the desired transmission state when the desired transmission state differs from the present transmission state, the motor drive signals including a clockwise motor drive signal, a counter-clockwise motor drive signal, a shift up motor drive signal and a shift down motor drive signal.

  20. High-Resolution Transmission Measurements of 233U Using a Cooled Sample at the Temperature T=11 K

    SciTech Connect

    Guber, Klaus H; Spencer, R. R.; Leal, Luiz C; Koehler, Paul Edward; Harvey, John A; Sayer, Royce O; Derrien, Herve; Valentine, Timothy E; Pierce, D. E.; Cauley, V Mike; Lewis, T A

    2001-01-01

    For the first time, high-resolution transmission data of {sup 233}U have been obtained using a cooled sample. The samples were cooled to T = 11 K using a cryogenic device, which reduced the Doppler broadening of resonances by 50% compared to room-temperature measurements. The measurements were carried out at the Oak Ridge Electron Linear Accelerator over the energy range from 0.6 eV to 300 keV at the 80-m flight path station. Corrections were made for experimental effects, and the average total cross section in this energy range was determined. Results are compared to previous measurements.

  1. The potential for Bayesian compressive sensing to significantly reduce electron dose in high-resolution STEM images.

    PubMed

    Stevens, Andrew; Yang, Hao; Carin, Lawrence; Arslan, Ilke; Browning, Nigel D

    2014-02-01

    The use of high-resolution imaging methods in scanning transmission electron microscopy (STEM) is limited in many cases by the sensitivity of the sample to the beam and the onset of electron beam damage (for example, in the study of organic systems, in tomography and during in situ experiments). To demonstrate that alternative strategies for image acquisition can help alleviate this beam damage issue, here we apply compressive sensing via Bayesian dictionary learning to high-resolution STEM images. These computational algorithms have been applied to a set of images with a reduced number of sampled pixels in the image. For a reduction in the number of pixels down to 5% of the original image, the algorithms can recover the original image from the reduced data set. We show that this approach is valid for both atomic-resolution images and nanometer-resolution studies, such as those that might be used in tomography datasets, by applying the method to images of strontium titanate and zeolites. As STEM images are acquired pixel by pixel while the beam is scanned over the surface of the sample, these postacquisition manipulations of the images can, in principle, be directly implemented as a low-dose acquisition method with no change in the electron optics or the alignment of the microscope itself.

  2. Mass-mapping of ECM macromolecules by scanning transmission electron microscopy.

    PubMed

    Sherratt, Michael J; Graham, Helen K; Kielty, Cay M; Holmes, David F

    2009-01-01

    In the scanning transmission electron microscope, the degree of electron scattering induced by biological specimens, such as ECM macromolecules, is dependent on the molecular mass. By calibrating the ratio of scattered to non-scattered electrons against a known mass standard, such as tobacco mosaic virus, it is possible to quantify absolute changes in both mass and mass distribution. These mass mapping approaches can provide important information on ECM assembly, organisation, and interactions which is not obtainable by other means.

  3. Electron transmission through bilayer graphene: A time-dependent first-principles study

    NASA Astrophysics Data System (ADS)

    Miyauchi, Hironari; Ueda, Yoshihiro; Suzuki, Yasumitsu; Watanabe, Kazuyuki

    2017-03-01

    Incident-energy-dependent electron transmittances through single-layer graphene (SLG) and bilayer graphene (BLG) were investigated using time-dependent density functional theory. The transmittances of BLG with two kinds of stacking exhibit an unexpected crossing at a certain incident electron energy. The behavior is preserved for the BLG with reduced or increased layer distances compared to that of typical BLG. We determined the origin of the crossing by investigating transmission electron diffraction patterns for SLG.

  4. High-efficiency blazed transmission gratings for high-resolution soft x-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Heilmann, Ralf K.; Bruccoleri, Alexander R.; Schattenburg, Mark L.

    2015-09-01

    High-resolution spectroscopy of astrophysical sources is the key to gaining a quantitative understanding of the history, dynamics, and current conditions of the cosmos. A large-area (> 1,000 cm2), high resolving power (R = λ/Δλ> 3000) soft x-ray grating spectrometer (XGS) that covers the lines of C, N, O, Ne and Fe ions is the ideal tool to address a number of high-priority science questions from the 2010 Decadal Survey, such as the connection between super-massive black holes and large-scale structure via cosmic feedback, the evolution of large- scale structure, the behavior of matter at high densities, and the conditions close to black holes. While no grating missions or instruments are currently approved, an XGS aboard a potential future X-ray Surveyor could easily surpass the above performance metrics. To improve the chances for future soft x-ray grating spectroscopy missions or instruments, grating technology has to progress and advance to higher Technology Readiness Levels (TRLs). To that end we have developed Critical-Angle Transmission (CAT) gratings that combine the advantages of blazed reflection gratings (high efficiency, use of higher diffraction orders) with those of conventional transmission gratings (low mass, relaxed alignment tolerances and temperature requirements, high transparency at higher energies). A CAT grating-based spectrometer can provide performance 1-2 orders of magnitude better than current grating instruments on Chandra and Newton-XMM with minimal resource requirements. At present we have fabricated large-area freestanding CAT gratings with narrow integrated support structures from silicon-on- insulator wafers using advanced lithography and a combination of deep reactive-ion and wet etching. Our latest x-ray test results show record high absolute diffraction efficiencies in blazed orders in excess of 30% with room for improvement.

  5. Development of a monochromator for aberration-corrected scanning transmission electron microscopy.

    PubMed

    Mukai, Masaki; Okunishi, Eiji; Ashino, Masanori; Omoto, Kazuya; Fukuda, Tomohisa; Ikeda, Akihiro; Somehara, Kazunori; Kaneyama, Toshikatsu; Saitoh, Tomohiro; Hirayama, Tsukasa; Ikuhara, Yuichi

    2015-06-01

    In this article, we report the development of a new 200-kV analytical electron microscope equipped with a monochromator with an integrated double Wien-filter system. It enables us to study the electronic structures of materials in detail using electron energy-loss spectroscopy (EELS) analysis at an atomic scale. A highly monochromated and isotropically round electron probe is produced on the specimen plane. The ultimate energy resolutions with 0.1-s acquisition times are measured to be 36 meV at 200 kV and 30 meV at 60 kV. In an EELS mapping experiment performed on SrTiO3 with a monochromated electron probe whose energy resolution is 146 meV, an elemental map exhibits atomic resolution.

  6. Chromatic aberration-corrected tilt series transmission electron microscopy of nanoparticles in a whole mount macrophage cell.

    PubMed

    Baudoin, Jean-Pierre; Jinschek, Joerg R; Boothroyd, Chris B; Dunin-Borkowski, Rafal E; de Jonge, Niels

    2013-08-01

    Transmission electron microscopy (TEM) in combination with electron tomography is widely used to obtain nanometer scale three-dimensional (3D) structural information about biological samples. However, studies of whole eukaryotic cells are limited in resolution and/or contrast on account of the effect of chromatic aberration of the TEM objective lens on electrons that have been scattered inelastically in the specimen. As a result, 3D information is usually obtained from sections and not from whole cells. Here, we use chromatic aberration-corrected TEM to record bright-field TEM images of nanoparticles in a whole mount macrophage cell. Tilt series of images are used to generate electron tomograms, which are analyzed to assess the spatial resolution that can be achieved for different vertical positions in the specimen. The uptake of gold nanoparticles coated with low-density lipoprotein (LDL) is studied. The LDL is found to assemble in clusters. The clusters contain nanoparticles taken up on different days, which are joined without mixing their nanoparticle cargo.

  7. Transmission electron microscopic pathoanatomy of congenital trigger thumb.

    PubMed

    Buchman, M T; Gibson, T W; McCallum, D; Cuda, D D; Ramos, A G

    1999-01-01

    Previous studies of trigger digits in children have been limited to gross morphology and light-microscopic histology. Nine children with 11 trigger thumbs formed a preliminary study group for electron-microscopic evaluation of tendon nodules and A-1 pulleys. This pathoanatomic investigation was not previously reported. Comparison was made with light-microscopic sections. Large amounts of mature collagen was observed. Fibroblasts with prominent rough endoplasmic reticulum were present. No degenerative or inflammatory changes were noted in either tendon or sheath. We believe that although the etiology of trigger digits is still uncertain, an infectious, inflammatory, or degenerative process is unlikely.

  8. High resolution simulation of beam dynamics in electron linacs for x-ray free electron lasers

    NASA Astrophysics Data System (ADS)

    Qiang, J.; Ryne, R. D.; Venturini, M.; Zholents, A. A.; Pogorelov, I. V.

    2009-10-01

    In this paper we report on large-scale high resolution simulations of beam dynamics in electron linacs for the next-generation x-ray free electron lasers (FELs). We describe key features of a parallel macroparticle simulation code including three-dimensional (3D) space-charge effects, short-range structure wakefields, coherent synchrotron radiation (CSR) wakefields, and treatment of radio-frequency (rf) accelerating cavities using maps obtained from axial field profiles. We present a study of the microbunching instability causing severe electron beam fragmentation in the longitudinal phase space which is a critical issue for future FELs. Using parameters for a proposed FEL linac at Lawrence Berkeley National Laboratory (LBNL), we show that a large number of macroparticles (beyond 100 million) is generally needed to control the numerical macroparticle shot noise and avoid overestimating the microbunching instability. We explore the effect of the longitudinal grid on simulation results. We also study the effect of initial uncorrelated energy spread on the final uncorrelated energy spread of the beam for the FEL linac.

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

    PubMed

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

    2016-10-27

    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.

  10. Indium redistribution in an InGaN quantum well induced by electron-beam irradiation in a transmission electron microscope

    SciTech Connect

    Li, T.; Hahn, E.; Gerthsen, D.; Rosenauer, A.; Strittmatter, A.; Reissmann, L.; Bimberg, D.

    2005-06-13

    The change of the morphology and indium distribution in an In{sub 0.12}Ga{sub 0.88}N quantum well embedded in GaN was investigated depending on the duration of electron-beam irradiation in a transmission electron microscope. Strain-state analysis based on high-resolution lattice-fringe images was used to determine quantitatively the local and average indium concentration of the InGaN quantum well. In-rich clusters were found already in the first image taken after 20 s of irradiation. The indium concentration in the clusters tends to increase with prolonged irradiation time. In contrast, the locally averaged indium concentration and the quantum-well width do not change within the first minute.

  11. Big Data Analytics for Scanning Transmission Electron Microscopy Ptychography

    PubMed Central

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

    2016-01-01

    Electron microscopy is undergoing a transition; from the model of producing only a few micrographs, through the current state where many images and spectra can be digitally recorded, to a new mode where very large volumes of data (movies, ptychographic and multi-dimensional series) can be rapidly obtained. Here, we discuss the application of so-called “big-data” methods to high dimensional microscopy data, using unsupervised multivariate statistical techniques, in order to explore salient image features in a specific example of BiFeO3 domains. Remarkably, k-means clustering reveals domain differentiation despite the fact that the algorithm is purely statistical in nature and does not require any prior information regarding the material, any coexisting phases, or any differentiating structures. While this is a somewhat trivial case, this example signifies the extraction of useful physical and structural information without any prior bias regarding the sample or the instrumental modality. Further interpretation of these types of results may still require human intervention. However, the open nature of this algorithm and its wide availability, enable broad collaborations and exploratory work necessary to enable efficient data analysis in electron microscopy. PMID:27211523

  12. Big Data Analytics for Scanning Transmission Electron Microscopy Ptychography

    SciTech Connect

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

    2016-05-23

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

  13. Big Data Analytics for Scanning Transmission Electron Microscopy Ptychography

    DOE PAGES

    Jesse, S.; Chi, M.; Belianinov, A.; ...

    2016-05-23

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

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

    PubMed

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

    2016-05-23

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

  15. Big Data Analytics for Scanning Transmission Electron Microscopy Ptychography

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  16. Transmission electron microscopy of deformed omphacite from the Tauern Window (Eastern Alps)

    NASA Astrophysics Data System (ADS)

    Mueller, W. F.; Brenker, F. E.; Barnert, E.; Franz, G.

    2003-04-01

    Deformed omphacite from an eclogite sample of the Lower Schist Cover of the Tauern Window was studied by conventional and high resolution transmission electron microscopy. The formation conditions of this eclogite were 400 to 500 °C at 8 to 12 kbar (Zimmermann &Franz, 1988); radiometric age dating yielded a formation age of about 420 Ma (von Quadt et al., 1997). The electron diffraction patterns of the omphacite grains (40 to 50 mol-% Jd) contained almost always reflections of the type h + k odd. The following microstructures were observed: antiphase domains, perfect and partial dislocations, chain multiplicity faults (CMFs), low angle grain boundaries, recrystallized grains, exsolution lamellae, barroisite precipitates, titanite and rutile inclusions. The CMFs are mostly intercalations of one or two double chain slabs parallel to (010) into the single chain omphacite, are up to 3 µm long, often terminated by partial dislocations, and were seen in most omphacite grains of suitable orientation. The CMFs contain often small steps and display even hairpin-like turns. Contrast analysis showed that the displacement vector R and the Burgers vector b of the partial dislocations is probably 1/2[011], less likely 1/2[101]. It is assumed that the CMFs were formed by stress-induced dissociation of [011] dislocations. A direct proof of CMFs acting as slip plane has been observed at a low angle grain boundary which was displaced along an CMF. The frequent occurrence of CMFs in omphacite suggests that 1/2[011](010) is an important slip system which is probably responsible for lattice preferred orientation. The interaction observed between CMFs and APBs provides a recovery mechanism hitherto not reported from omphacite. To the best of our knowledge, CMFs in omphacite, especially such formed by dissociation of dislocations, have not been analysed before by other authors, although they have been probably seen by Buatier et al. (1991) and Godard &Roermund (1995).

  17. Imaging heterostructured quantum dots in cultured cells with epifluorescence and transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Rivera, Erin M.; Trujillo Provencio, Casilda; Steinbrueck, Andrea; Rastogi, Pawan; Dennis, Allison; Hollingsworth, Jennifer; Serrano, Elba

    2011-03-01

    Quantum dots (QDs) are semiconductor nanocrystals with extensive imaging and diagnostic capabilities, including the potential for single molecule tracking. Commercially available QDs offer distinct advantages over organic fluorophores, such as increased photostability and tunable emission spectra, but their cadmium selenide (CdSe) core raises toxicity concerns. For this reason, replacements for CdSe-based QDs have been sought that can offer equivalent optical properties. The spectral range, brightness and stability of InP QDs may comprise such a solution. To this end, LANL/CINT personnel fabricated moderately thick-shell novel InP QDs that retain brightness and emission over time in an aqueous environment. We are interested in evaluating how the composition and surface properties of these novel QDs affect their entry and sequestration within the cell. Here we use epifluorescence and transmission electron microscopy (TEM) to evaluate the structural properties of cultured Xenopus kidney cells (A6; ATCC) that were exposed either to commercially available CdSe QDs (Qtracker® 565, Invitrogen) or to heterostructured InP QDs (LANL). Epifluorescence imaging permitted assessment of the general morphology of cells labeled with fluorescent molecular probes (Alexa Fluor® ® phalloidin; Hoechst 33342), and the prevalence of QD association with cells. In contrast, TEM offered unique advantages for viewing electron dense QDs at higher resolution with regard to subcellular sequestration and compartmentalization. Preliminary results show that in the absence of targeting moieties, InP QDs (200 nM) can passively enter cells and sequester nonspecifically in cytosolic regions whereas commercially available targeted QDs principally associate with membranous structures within the cell. Supported by: NIH 5R01GM084702.

  18. Large-scale Scanning Transmission Electron Microscopy (Nanotomy) of Healthy and Injured Zebrafish Brain

    PubMed Central

    Kuipers, Jeroen; Kalicharan, Ruby D.; Wolters, Anouk H. G.

    2016-01-01

    Large-scale 2D electron microscopy (EM), or nanotomy, is the tissue-wide application of nanoscale resolution electron microscopy. Others and we previously applied large scale EM to human skin pancreatic islets, tissue culture and whole zebrafish larvae1-7. Here we describe a universally applicable method for tissue-scale scanning EM for unbiased detection of sub-cellular and molecular features. Nanotomy was applied to investigate the healthy and a neurodegenerative zebrafish brain. Our method is based on standardized EM sample preparation protocols: Fixation with glutaraldehyde and osmium, followed by epoxy-resin embedding, ultrathin sectioning and mounting of ultrathin-sections on one-hole grids, followed by post staining with uranyl and lead. Large-scale 2D EM mosaic images are acquired using a scanning EM connected to an external large area scan generator using scanning transmission EM (STEM). Large scale EM images are typically ~ 5 - 50 G pixels in size, and best viewed using zoomable HTML files, which can be opened in any web browser, similar to online geographical HTML maps. This method can be applied to (human) tissue, cross sections of whole animals as well as tissue culture1-5. Here, zebrafish brains were analyzed in a non-invasive neuronal ablation model. We visualize within a single dataset tissue, cellular and subcellular changes which can be quantified in various cell types including neurons and microglia, the brain's macrophages. In addition, nanotomy facilitates the correlation of EM with light microscopy (CLEM)8 on the same tissue, as large surface areas previously imaged using fluorescent microscopy, can subsequently be subjected to large area EM, resulting in the nano-anatomy (nanotomy) of tissues. In all, nanotomy allows unbiased detection of features at EM level in a tissue-wide quantifiable manner. PMID:27285162

  19. Large-scale Scanning Transmission Electron Microscopy (Nanotomy) of Healthy and Injured Zebrafish Brain.

    PubMed

    Kuipers, Jeroen; Kalicharan, Ruby D; Wolters, Anouk H G; van Ham, Tjakko J; Giepmans, Ben N G

    2016-05-25

    Large-scale 2D electron microscopy (EM), or nanotomy, is the tissue-wide application of nanoscale resolution electron microscopy. Others and we previously applied large scale EM to human skin pancreatic islets, tissue culture and whole zebrafish larvae(1-7). Here we describe a universally applicable method for tissue-scale scanning EM for unbiased detection of sub-cellular and molecular features. Nanotomy was applied to investigate the healthy and a neurodegenerative zebrafish brain. Our method is based on standardized EM sample preparation protocols: Fixation with glutaraldehyde and osmium, followed by epoxy-resin embedding, ultrathin sectioning and mounting of ultrathin-sections on one-hole grids, followed by post staining with uranyl and lead. Large-scale 2D EM mosaic images are acquired using a scanning EM connected to an external large area scan generator using scanning transmission EM (STEM). Large scale EM images are typically ~ 5 - 50 G pixels in size, and best viewed using zoomable HTML files, which can be opened in any web browser, similar to online geographical HTML maps. This method can be applied to (human) tissue, cross sections of whole animals as well as tissue culture(1-5). Here, zebrafish brains were analyzed in a non-invasive neuronal ablation model. We visualize within a single dataset tissue, cellular and subcellular changes which can be quantified in various cell types including neurons and microglia, the brain's macrophages. In addition, nanotomy facilitates the correlation of EM with light microscopy (CLEM)(8) on the same tissue, as large surface areas previously imaged using fluorescent microscopy, can subsequently be subjected to large area EM, resulting in the nano-anatomy (nanotomy) of tissues. In all, nanotomy allows unbiased detection of features at EM level in a tissue-wide quantifiable manner.

  20. Transmission electron microscopy, photoluminescence, and capacitance spectroscopy on GaAs/Si grown by metal organic chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Bremond, Georges E.; Said, Hicham; Guillot, Gerard; Meddeb, Jaafar; Pitaval, M.; Draidia, Nasser; Azoulay, Rozette

    1991-03-01

    We present a complete characterization study of GaAs/Si heteroepitaxial layers grown by metalorganic chemical vapor deposition (MOCVD) at 750C using the two-step method. High resolution transmission electron microscopy secondary ion mass spectroscopy deep level transient spectroscopy (DLTS) and photoluminescence (PL) spectroscopy have been performed to study the initial stage of growth misfit and threading dislocations Si diffusion and the deep levels in the GaAs layer. We describe the influence of GaAs/AlAs superlattices in the buffer layer on the decrease of dislocation density and on Si diffusion from the substrate and the existence of deep electron traps induced by the heteroepitaxy. DLTS reveals hole traps attributed to Si incorporation on the basis of PL measurements which could contribute to the reduction of the minority carrier lifetime. We also show an improvement of the layer quality by the use of selective epitaxy.

  1. Nanoimaging and spectroscopic analysis of rubber/ZnO interfaces by energy-filtering transmission electron microscopy.

    PubMed

    Horiuchi, Shin; Dohi, Hidehiko

    2006-05-09

    Energy-filtering transmission electron microscopy (EFTEM) was employed for investigating interactions between rubber and ZnO particles in the accelerated vulcanization process. Combining elemental mapping and electron energy loss spectroscopy (EELS) by EFTEM enabled the characterization of the interfaces with spatial resolutions of less than 10 nm and with high elemental detection sensitivity. We found that a sulfur- and zinc-rich compound was generated around ZnO particles, and that product was then revealed to be ZnS-generated as a byproduct in the accelerated vulcanization process. Through this study, it is indicated that the accelerated vulcanization with ZnO does not occur uniformly in the rubber matrix; it occurs locally around ZnO particles at a higher reaction rate, implying that the rubber network structure is not uniform on the nanoscale.

  2. Automatic grading of carbon blacks from transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Luengo, L.; Treuillet, S.; Gomez, E.

    2015-04-01

    Carbon blacks are widely used as filler in industrial products to modify their mechanical, electrical and optical properties. For rubber products, they are the subject of a standard classification system relative to their surface area, particle size and structure. The electron microscope remains the most accurate means of measuring these characteristics on condition that boundaries of aggregates and particles are correctly detected. In this paper, we propose an image processing chain allowing subsequent characterization for automatic grading of the carbon black aggregates. Based on literature review, 31 features are extracted from TEM images to obtain reliable information on the particle size, the shape and microstructure of the carbon black aggregates. Then, they are used for training several classifiers to compare their results for automatic grading. To obtain better results, we suggest to use a cluster identification of aggregates in place of the individual characterization of aggregates.

  3. In situ transmission electron microscopy of cadmium selenide nanorod sublimation

    SciTech Connect

    Hellebusch, Daniel J.; Manthiram, Karthish; Beberwyck, Brandon J.; Alivisatos, A. Paul

    2015-01-23

    In situ electron microscopy is used to observe the morphological evolution of cadmium selenide nanorods as they sublime under vacuum at a series of elevated temperatures. Mass loss occurs anisotropically along the nanorod’s long axis. At temperatures close to the sublimation threshold, the phase change occurs from both tips of the nanorods and proceeds unevenly with periods of rapid mass loss punctuated by periods of relative stability. At higher temperatures, the nanorods sublime at a faster, more uniform rate, but mass loss occurs from only a single end of the rod. Furthermore, we propose a mechanism that accounts for the observed sublimation behavior based on the terrace–ledge–kink (TLK) model and how the nanorod surface chemical environment influences the kinetic barrier of sublimation.

  4. In Situ Transmission Electron Microscopy of Cadmium Selenide Nanorod Sublimation.

    PubMed

    Hellebusch, Daniel J; Manthiram, Karthish; Beberwyck, Brandon J; Alivisatos, A Paul

    2015-02-19

    In situ electron microscopy is used to observe the morphological evolution of cadmium selenide nanorods as they sublime under vacuum at a series of elevated temperatures. Mass loss occurs anisotropically along the nanorod's long axis. At temperatures close to the sublimation threshold, the phase change occurs from both tips of the nanorods and proceeds unevenly with periods of rapid mass loss punctuated by periods of relative stability. At higher temperatures, the nanorods sublime at a faster, more uniform rate, but mass loss occurs from only a single end of the rod. We propose a mechanism that accounts for the observed sublimation behavior based on the terrace-ledge-kink (TLK) model and how the nanorod surface chemical environment influences the kinetic barrier of sublimation.

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

    PubMed

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

    2009-04-01

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

  6. In situ transmission electron microscopy of cadmium selenide nanorod sublimation

    DOE PAGES

    Hellebusch, Daniel J.; Manthiram, Karthish; Beberwyck, Brandon J.; ...

    2015-01-23

    In situ electron microscopy is used to observe the morphological evolution of cadmium selenide nanorods as they sublime under vacuum at a series of elevated temperatures. Mass loss occurs anisotropically along the nanorod’s long axis. At temperatures close to the sublimation threshold, the phase change occurs from both tips of the nanorods and proceeds unevenly with periods of rapid mass loss punctuated by periods of relative stability. At higher temperatures, the nanorods sublime at a faster, more uniform rate, but mass loss occurs from only a single end of the rod. Furthermore, we propose a mechanism that accounts for themore » observed sublimation behavior based on the terrace–ledge–kink (TLK) model and how the nanorod surface chemical environment influences the kinetic barrier of sublimation.« less

  7. Numerical simulation of microwave transmission in the presence of an electron cloud

    NASA Astrophysics Data System (ADS)

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

    2007-11-01

    Electron cloud effects on the transmission of microwaves through beam pipes in the CERN SPS experiment and the PEP-II Low Energy Ring (LER) at SLAC have been recently observed. Electrons within the vacuum chamber generated primarily via secondary electron emission have been observed to cause a phase shift in microwaves injected into the vacuum chamber. Understanding this effect may provide a useful diagnostic tool for measuring electron cloud densities in accelerators. We present numerical simulation results generated by the electromagnetic Particle-In-Cell (PIC) code VORPAL, which predicts this phase shift. We also measure the effects of non-uniform electron cloud density and externally applied magnetic fields on the transmission properties, and compare our predictions to recent experiments at the PEP-II LER.

  8. Vertical profiles of aerosol volume from high-spectral-resolution infrared transmission measurements. I. Methodology.

    PubMed

    Eldering, A; Irion, F W; Chang, A Y; Gunson, M R; Mills, F P; Steele, H M

    2001-06-20

    The wavelength-dependent aerosol extinction in the 800-1250-cm(-1) region has been derived from ATMOS (atmospheric trace molecule spectroscopy) high-spectral-resolution IR transmission measurements. Using models of aerosol and cloud extinction, we have performed weighted nonlinear least-squares fitting to determine the aerosol-volume columns and vertical profiles of stratospheric sulfate aerosol and cirrus cloud volume. Modeled extinction by use of cold-temperature aerosol optical constants for a 70-80% sulfuric-acid-water solution shows good agreement with the measurements, and the derived aerosol volumes for a 1992 occultation are consistent with data from other experiments after the eruption of Mt. Pinatubo. The retrieved sulfuric acid aerosol-volume profiles are insensitive to the aerosol-size distribution and somewhat sensitive to the set of optical constants used. Data from the nonspherical cirrus extinction model agree well with a 1994 mid-latitude measurement indicating the presence of cirrus clouds at the tropopause.

  9. Proton Transmitting Energy Spectra and Transmission Electron Microscope Examinations of Biological Samples

    NASA Astrophysics Data System (ADS)

    Tan, Chun-yu; Xia, Yue-yuan; Zhang, Jian-hua; Mu, Yu-guang; Wang, Rui-jin; Liu, Ji-tian; Liu, Xiang-dong; Yu, Zeng-liang

    1999-02-01

    Transmission energy spectra of 530 keV H+ ion penetrating 140 μm thick seed coat of maize and fruit peel of grape with thickness of 100 μm were measured. The result indicates that these thick biological targets, as seen by the penetrating ions, are inhomogeneous, and there are open "channel like" paths along which the incident ions can transmit the targets easily. While most of the incident ions are stopped in the targets, some of the transmitting ions only lose a small fraction of their initial incident energy. The transmission energy spectra show a pure electronic stopping feature. Transmission electron microscope (TEM) micrographes taken from the samples of seed coat of maize and fruit peel of tomato with thickness of 60 μm indicate that 150 keV electron beam from the TEM can penetrate the thick samples to give very good images with clear contrasts.

  10. Degradation of spatial resolution in thin-foil x-ray microchemical analysis due to plural scattering of electrons

    SciTech Connect

    Twigg, Mark Erickson

    1982-01-01

    A computer-based Monte Carlo simulation of incoherent plural scattering of electrons has been developed in order to estimate the broadening of an electron probe as it propagates through a solid. By applying this approach to modeling the spreading of a fine (50 A) probe focused on a thin foil in a scanning transmission electron microscope (STEM), we have estimated the spatial resolution of the compositional analysis obtainable using energy dispersive x-ray spectroscopy (EDS). Specifically, an attempt has been made to determine how the apparent microchemistry of a feature of finer dimensions than the broadened beam differs from the actual composition of the given feature. The apparent Ge concentration profile in the vicinity of a 200 A wide Ge platelet in a 5000 A thick Al foil was measured, using STEM and EDS, and compared with the profile predicted by Monte Carlo calculations. Results are presented and discussed.

  11. Detection of local chemical states of lithium and their spatial mapping by scanning transmission electron microscopy, electron energy-loss spectroscopy and hyperspectral image analysis.

    PubMed

    Muto, Shunsuke; Tatsumi, Kazuyoshi

    2017-02-08

    Advancements in the field of renewable energy resources have led to a growing demand for the analysis of light elements at the nanometer scale. Detection of lithium is one of the key issues to be resolved for providing guiding principles for the synthesis of cathode active materials, and degradation analysis after repeated use of those materials. We have reviewed the different techniques currently used for the characterization of light elements such as high-resolution transmission electron microscopy, scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS). In the present study, we have introduced a methodology to detect lithium in solid materials, particularly for cathode active materials used in lithium-ion battery. The chemical states of lithium were isolated and analyzed from the overlapping multiple spectral profiles, using a suite of STEM, EELS and hyperspectral image analysis. The method was successfully applied in the chemical state analyses of hetero-phases near the surface and grain boundary regions of the active material particles formed by chemical reactions between the electrolyte and the active materials.

  12. Transmission Electron Microscopy of Bombyx Mori Silk Fibers

    NASA Astrophysics Data System (ADS)

    Shen, Y.; Martin, D. C.

    1997-03-01

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

  13. Removal of Vesicle Structures From Transmission Electron Microscope Images

    PubMed Central

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

    2016-01-01

    In this paper, we address the problem of imaging membrane proteins for single-particle cryo-electron microscopy reconstruction of the isolated protein structure. More precisely, we propose a method for learning and removing the interfering vesicle signals from the micrograph, prior to reconstruction. In our approach, we estimate the subspace of the vesicle structures and project the micrographs onto the orthogonal complement of this subspace. We construct a 2d statistical model of the vesicle structure, based on higher order singular value decomposition (HOSVD), by considering the structural symmetries of the vesicles in the polar coordinate plane. We then propose to lift the HOSVD model to a novel hierarchical model by summarizing the multidimensional HOSVD coefficients by their principal components. Along with the model, a solid vesicle normalization scheme and model selection criterion are proposed to make a compact and general model. The results show that the vesicle structures are accurately separated from the background by the HOSVD model that is also able to adapt to the asymmetries of the vesicles. This is a promising result and suggests even wider applicability of the proposed approach in learning and removal of statistical structures. PMID:26642456

  14. Visualization of newt aragonitic otoconial matrices using transmission electron microscopy

    NASA Technical Reports Server (NTRS)

    Steyger, P. S.; Wiederhold, M. L.

    1995-01-01

    Otoconia are calcified protein matrices within the gravity-sensing organs of the vertebrate vestibular system. These protein matrices are thought to originate from the supporting or hair cells in the macula during development. Previous studies of mammalian calcitic, barrel-shaped otoconia revealed an organized protein matrix consisting of a thin peripheral layer, a well-defined organic core and a flocculent matrix inbetween. No studies have reported the microscopic organization of the aragonitic otoconial matrix, despite its protein characterization. Pote et al. (1993b) used densitometric methods and inferred that prismatic (aragonitic) otoconia have a peripheral protein distribution, compared to that described for the barrel-shaped, calcitic otoconia of birds, mammals, and the amphibian utricle. By using tannic acid as a negative stain, we observed three kinds of organic matrices in preparations of fixed, decalcified saccular otoconia from the adult newt: (1) fusiform shapes with a homogenous electron-dense matrix; (2) singular and multiple strands of matrix; and (3) more significantly, prismatic shapes outlined by a peripheral organic matrix. These prismatic shapes remain following removal of the gelatinous matrix, revealing an internal array of organic matter. We conclude that prismatic otoconia have a largely peripheral otoconial matrix, as inferred by densitometry.

  15. Utility of Transmission Electron Microscopy in Small Round Cell Tumors

    PubMed Central

    Kim, Na Rae; Ha, Seung Yeon; Cho, Hyun Yee

    2015-01-01

    Small round cell tumors (SRCTs) are a heterogeneous group of neoplasms composed of small, primitive, and undifferentiated cells sharing similar histology under light microscopy. SRCTs include Ewing sarcoma/peripheral neuroectodermal tumor family tumors, neuroblastoma, desmoplastic SRCT, rhabdomyosarcoma, poorly differentiated round cell synovial sarcoma, mesenchymal chondrosarcoma, small cell osteosarcoma, small cell malignant peripheral nerve sheath tumor, and small cell schwannoma. Non-Hodgkin’s malignant lymphoma, myeloid sarcoma, malignant melanoma, and gastrointestinal stromal tumor may also present as SRCT. The current shift towards immunohistochemistry and cytogenetic molecular techniques for SRCT may be inappropriate because of antigenic overlapping or inconclusive molecular results due to the lack of differentiation of primitive cells and unavailable genetic service or limited moleculocytogenetic experience. Although usage has declined, electron microscopy (EM) remains very useful and shows salient features for the diagnosis of SRCTs. Although EM is not always required, it provides reliability and validity in the diagnosis of SRCT. Here, the ultrastructural characteristics of SRCTs are reviewed and we suggest that EM would be utilized as one of the reliable modalities for the diagnosis of undifferentiated and poorly differentiated SRCTs. PMID:25812730

  16. Scanning and Transmission Electron Microscopy of High Temperature Materials

    NASA Technical Reports Server (NTRS)

    1994-01-01

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

  17. Probing core-electron orbitals by scanning transmission electron microscopy and measuring the delocalization of core-level excitations

    NASA Astrophysics Data System (ADS)

    Jeong, Jong Seok; Odlyzko, Michael L.; Xu, Peng; Jalan, Bharat; Mkhoyan, K. Andre

    2016-04-01

    By recording low-noise energy-dispersive x-ray spectroscopy maps from crystalline specimens using aberration-corrected scanning transmission electron microscopy, it is possible to probe core-level electron orbitals in real space. Both the 1 s and 2 p orbitals of Sr and Ti atoms in SrTi O3 are probed, and their projected excitation potentials are determined. This paper also demonstrates experimental measurement of the electronic excitation impact parameter and the delocalization of an excitation due to Coulombic beam-orbital interaction.

  18. Electron-beam irradiation induced conductivity in ZnS nanowires as revealed by in situ transmission electron microscope

    NASA Astrophysics Data System (ADS)

    Liu, Baodan; Bando, Yoshio; Wang, Mingsheng; Zhi, Chunyi; Fang, Xiaosheng; Tang, Chengchun; Mitome, Masanori; Golberg, Dmitri

    2009-08-01

    Electron transport variations in individual ZnS nanowires synthesized through a chemical vapor deposition process were in situ studied in transmission electron microscope under convergent electron-beam irradiation (EBI). It was found that the transport can dramatically be enhanced using proper irradiation conditions. The conductivity mechanism was revealed based on a detailed study of microstructure and composition evolutions under irradiation. EBI-induced Zn-rich domains' appearance and related O doping were mainly responsible for the conductivity improvements. First-principles theoretical calculations additionally indicated that the generation of midbands within a ZnS band gap might also contribute to the improved conductivity.

  19. Ultrasensitive Scanning Transmission X-ray Microscopy: Pushing the Limits of Time Resolution and Magnetic Sensitivity

    NASA Astrophysics Data System (ADS)

    Ohldag, Hendrik

    Understanding magnetic properties at ultrafast timescales is crucial for the development of new magnetic devices. Samples of interest are often thin film magnetic multilayers with thicknesses in the range of a few atomic layers. This fact alone presents a sensitivity challenge in STXM microscopy, which is more suited toward studying thicker samples. In addition the relevant time scale is of the order of 10 ps, which is well below the typical x-ray pulse length of 50 - 100 ps. The SSRL STXM is equipped with a single photon counting electronics that effectively allows using a double lock-in detection at 476MHz (the x-ray pulse frequency) and 1.28MHz (the synchrotron revelation frequency) to provide the required sensitivity. In the first year of operation the excellent spatial resolution, temporal stability and sensitivity of the detection electronics of this microscope has enabled researchers to acquire time resolved images of standing as well as traveling spin waves in a spin torque oscillator in real space as well as detect the real time spin accumulation in non magnetic Copper once a spin polarized current is injected into this material. The total magnetic moment is comparable to that of a single nanocube of magnetic Fe buried under a micron of non-magnetic material.

  20. Transmission electron microscopy investigations of AZ91 alloy deformed by equal-channel angular pressing.

    PubMed

    Braszczyńska-Malik, K N; Lityńska, L; Baliga, W

    2006-10-01

    The microstructure of transverse and longitudinal sections of a commercial AZ91 alloy processed by equal-channel angular pressing was examined by transmission electron microscopy. A high dislocation density and large number of deformation twins were observed in the investigated material. The {102}(matrix) // {012}(twin) twinning system was determined by selection area diffraction patterns obtained from the twin and matrix. Transmission electron microscopy analyses also revealed that the twins interacted with each other and pile-ups of dislocations occurred near the twin boundary.