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Sample records for three-dimensional electron microscopic

  1. Three-Dimensional Orientation Mapping in the Transmission Electron Microscope

    DEFF Research Database (Denmark)

    Liu, Haihua; Schmidt, Søren; Poulsen, Henning Friis

    2011-01-01

    resolution of 200 nanometers (nm). We describe here a nondestructive technique that enables 3D orientation mapping in the transmission electron microscope of mono- and multiphase nanocrystalline materials with a spatial resolution reaching 1 nm. We demonstrate the technique by an experimental study...

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

    Science.gov (United States)

    Jones, L; Nellist, P D

    2014-05-01

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

  3. Compact design of a transmission electron microscope-scanning tunneling microscope holder with three-dimensional coarse motion

    International Nuclear Information System (INIS)

    Svensson, K.; Jompol, Y.; Olin, H.; Olsson, E.

    2003-01-01

    A scanning tunneling microscope (STM) with a compact, three-dimensional, inertial slider design is presented. Inertial sliding of the STM tip, in three dimensions, enables coarse motion and scanning using only one piezoelectric tube. Using the same electronics both for scanning and inertial sliding, step lengths of less than 5% of the piezo range were achieved. The compact design, less than 1 cm3 in volume, ensures a low mechanical noise level and enables us to fit the STM into the sample holder of a transmission electron microscope (TEM), while maintaining atomic scale resolution in both STM and TEM imaging

  4. Three-dimensional architecture of hair-cell linkages as revealedby electron-microscopic tomography

    Energy Technology Data Exchange (ETDEWEB)

    Auer, Manfred; Koster, Bram; Ziese, Ulrike; Bajaj, Chandrajit; Volkmann, Niels; Wang, Da Neng; Hudspeth, A. James

    2006-07-28

    The senses of hearing and balance rest upon mechanoelectrical transduction by the hair bundles of hair cells in the inner ear. Located at the apical cellular surface, each hair bundle comprises several tens of stereocilia and a single kinocilium that are interconnected by extracellular proteinaceous links. Using electron-microscopic tomography of bullfrog saccular sensory epithelia, we examined the three-dimensional structures of ankle or basal links, kinociliary links, and tip links. We observed clear differences in the dimensions and appearances of the three links. We found two distinct populations of tip links suggestive of the involvement of two proteins or splice variants. We noted auxiliary links connecting the upper portions of tip links to the taller stereocilia. Tip links and auxiliary links show a tendency to adopt a globular conformation when disconnected from the membrane surface.

  5. Scanning photoelectron microscope for nanoscale three-dimensional spatial-resolved electron spectroscopy for chemical analysis.

    Science.gov (United States)

    Horiba, K; Nakamura, Y; Nagamura, N; Toyoda, S; Kumigashira, H; Oshima, M; Amemiya, K; Senba, Y; Ohashi, H

    2011-11-01

    In order to achieve nondestructive observation of the three-dimensional spatially resolved electronic structure of solids, we have developed a scanning photoelectron microscope system with the capability of depth profiling in electron spectroscopy for chemical analysis (ESCA). We call this system 3D nano-ESCA. For focusing the x-ray, a Fresnel zone plate with a diameter of 200 μm and an outermost zone width of 35 nm is used. In order to obtain the angular dependence of the photoelectron spectra for the depth-profile analysis without rotating the sample, we adopted a modified VG Scienta R3000 analyzer with an acceptance angle of 60° as a high-resolution angle-resolved electron spectrometer. The system has been installed at the University-of-Tokyo Materials Science Outstation beamline, BL07LSU, at SPring-8. From the results of the line-scan profiles of the poly-Si/high-k gate patterns, we achieved a total spatial resolution better than 70 nm. The capability of our system for pinpoint depth-profile analysis and high-resolution chemical state analysis is demonstrated. © 2011 American Institute of Physics

  6. Three-Dimensional (3D) Nanometrology Based on Scanning Electron Microscope (SEM) Stereophotogrammetry.

    Science.gov (United States)

    Tondare, Vipin N; Villarrubia, John S; Vlada R, András E

    2017-10-01

    Three-dimensional (3D) reconstruction of a sample surface from scanning electron microscope (SEM) images taken at two perspectives has been known for decades. Nowadays, there exist several commercially available stereophotogrammetry software packages. For testing these software packages, in this study we used Monte Carlo simulated SEM images of virtual samples. A virtual sample is a model in a computer, and its true dimensions are known exactly, which is impossible for real SEM samples due to measurement uncertainty. The simulated SEM images can be used for algorithm testing, development, and validation. We tested two stereophotogrammetry software packages and compared their reconstructed 3D models with the known geometry of the virtual samples used to create the simulated SEM images. Both packages performed relatively well with simulated SEM images of a sample with a rough surface. However, in a sample containing nearly uniform and therefore low-contrast zones, the height reconstruction error was ≈46%. The present stereophotogrammetry software packages need further improvement before they can be used reliably with SEM images with uniform zones.

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

    Science.gov (United States)

    de Jonge, Niels [Oak Ridge, TN

    2010-08-17

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

  8. Three-dimensional machining of carbon nanotube forests using water-assisted scanning electron microscope processing

    Energy Technology Data Exchange (ETDEWEB)

    Rajabifar, Bahram; Maschmann, Matthew R., E-mail: MaschmannM@missouri.edu [Department of Mechanical and Aerospace Engineering, University of Missouri, Columbia, Missouri 65211 (United States); Kim, Sanha; Hart, A. John [Department of Mechanical Engineering and Laboratory for Manufacturing and Productivity, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Slinker, Keith [Materials and Manufacturing Directorate, AFRL/RX, Air Force Research Lab, Ohio 45433 (United States); Universal Technology Corporation, Beavercreek, Ohio 45424 (United States); Ehlert, Gregory J. [Materials and Manufacturing Directorate, AFRL/RX, Air Force Research Lab, Ohio 45433 (United States)

    2015-10-05

    We demonstrate that vertically aligned carbon nanotubes (CNTs) can be precisely machined in a low pressure water vapor ambient using the electron beam of an environmental scanning electron microscope. The electron beam locally damages the irradiated regions of the CNT forest and also dissociates the water vapor molecules into reactive species including hydroxyl radicals. These species then locally oxidize the damaged region of the CNTs. The technique offers material removal capabilities ranging from selected CNTs to hundreds of cubic microns. We study how the material removal rate is influenced by the acceleration voltage, beam current, dwell time, operating pressure, and CNT orientation. Milled cuts with depths between 0–100 microns are generated, corresponding to a material removal rate of up to 20.1 μm{sup 3}/min. The technique produces little carbon residue and does not disturb the native morphology of the CNT network. Finally, we demonstrate direct machining of pyramidal surfaces and re-entrant cuts to create freestanding geometries.

  9. Three-dimensional machining of carbon nanotube forests using water-assisted scanning electron microscope processing

    Science.gov (United States)

    Rajabifar, Bahram; Kim, Sanha; Slinker, Keith; Ehlert, Gregory J.; Hart, A. John; Maschmann, Matthew R.

    2015-10-01

    We demonstrate that vertically aligned carbon nanotubes (CNTs) can be precisely machined in a low pressure water vapor ambient using the electron beam of an environmental scanning electron microscope. The electron beam locally damages the irradiated regions of the CNT forest and also dissociates the water vapor molecules into reactive species including hydroxyl radicals. These species then locally oxidize the damaged region of the CNTs. The technique offers material removal capabilities ranging from selected CNTs to hundreds of cubic microns. We study how the material removal rate is influenced by the acceleration voltage, beam current, dwell time, operating pressure, and CNT orientation. Milled cuts with depths between 0-100 microns are generated, corresponding to a material removal rate of up to 20.1 μm3/min. The technique produces little carbon residue and does not disturb the native morphology of the CNT network. Finally, we demonstrate direct machining of pyramidal surfaces and re-entrant cuts to create freestanding geometries.

  10. Three-dimensional apoptotic nuclear behavior analyzed by means of Field Emission in Lens Scanning Electron Microscope

    Directory of Open Access Journals (Sweden)

    S. Salucci

    2015-09-01

    Full Text Available Apoptosis is an essential biological function required during embryogenesis, tissue homeostasis, organ development and immune system regulation. It is an active cell death pathway involved in a variety of pathological conditions. During this process cytoskeletal proteins appear damaged and undergo an enzymatic disassembling, leading to formation of apoptotic features. This study was designed to examine the three-dimensional chromatin behavior and cytoskeleton involvement, in particular actin re-modeling. HL-60 cells, exposed to hyperthermia, a known apoptotic trigger, were examined by means of a Field Emission in Lens Scanning Electron Microscope (FEISEM. Ultrastructural observations revealed in treated cells the presence of apoptotic patterns after hyperthermia trigger. In particular, three-dimensional apoptotic chromatin rearrangements appeared involving the translocation of filamentous actin from cytoplasm to the nucleus. FEISEM immunogold techniques showed actin labeling and its precise three-dimensional localization in the diffuse chromatin, well separated from the condensed one. The actin presence in dispersed chromatin inside the apoptotic nucleus can be considered an important feature, indispensable to permit the apoptotic machinery evolution.

  11. Three-dimensional nanofabrication by electron-beam-induced deposition using 200-keV electrons in scanning transmission electron microscope

    International Nuclear Information System (INIS)

    Liu, Z.Q.; Mitsuishi, K.; Furuya, K.

    2005-01-01

    Attempts were made to fabricate three-dimensional nanostructures on and out of a substrate by electron-beam-induced deposition in a 200-kV scanning transmission electron microscope. Structures with parallel wires over the substrate surface were difficult to fabricate due to the direct deposition of wires on both top and bottom surfaces of the substrate. Within the penetration depth of the incident electron beam, nanotweezers were fabricated by moving the electron beam beyond different substrate layers. Combining the deposition of self-supporting wires and self-standing tips, complicated three-dimensional doll-like, flag-like, and gate-like nanostructures that extend out of the substrate were successfully fabricated with one-step or multi-step scans of the electron beam. Effects of coarsening, nucleation, and distortion during electron-beam-induced deposition are discussed. (orig.)

  12. Three-dimensional reconstruction of highly complex microscopic samples using scanning electron microscopy and optical flow estimation.

    Directory of Open Access Journals (Sweden)

    Ahmadreza Baghaie

    Full Text Available Scanning Electron Microscope (SEM as one of the major research and industrial equipment for imaging of micro-scale samples and surfaces has gained extensive attention from its emerge. However, the acquired micrographs still remain two-dimensional (2D. In the current work a novel and highly accurate approach is proposed to recover the hidden third-dimension by use of multi-view image acquisition of the microscopic samples combined with pre/post-processing steps including sparse feature-based stereo rectification, nonlocal-based optical flow estimation for dense matching and finally depth estimation. Employing the proposed approach, three-dimensional (3D reconstructions of highly complex microscopic samples were achieved to facilitate the interpretation of topology and geometry of surface/shape attributes of the samples. As a byproduct of the proposed approach, high-definition 3D printed models of the samples can be generated as a tangible means of physical understanding. Extensive comparisons with the state-of-the-art reveal the strength and superiority of the proposed method in uncovering the details of the highly complex microscopic samples.

  13. Investigation on the traceability of three dimensional scanning electron microscope measurements based on the stereo-pair technique

    DEFF Research Database (Denmark)

    Bariani, Paolo; De Chiffre, Leonardo; Hansen, Hans Nørgaard

    2005-01-01

    An investigation was carried out concerning the traceability of dimensional measurements performed with the scanning electron microscope (SEM) using reconstruction of surface topography through stereo-photogrammetry. A theoretical description of the effects that the main instrumental variables...... with the scanning electron microscope (SEM) using reconstruction of surface topography through stereo-photogrammetry. A theoretical description of the effects that the main instrumental variables and measurement parameters have on the reconstruction accuracy of any point on the surface of the object being imaged......-dimensional topography of the type C roughness standards showed good agreement with the nominal profile wavelength values. An investigation was carried out concerning the traceability of dimensional measurements performed with the scanning electron microscope (SEM) using reconstruction of surface topography through...

  14. Three-dimensional fine structure of the organization of microtubules in neurite varicosities by ultra-high voltage electron microscope tomography.

    Science.gov (United States)

    Nishida, Tomoki; Yoshimura, Ryoichi; Endo, Yasuhisa

    2017-09-01

    Neurite varicosities are highly specialized compartments that are involved in neurotransmitter/ neuromodulator release and provide a physiological platform for neural functions. However, it remains unclear how microtubule organization contributes to the form of varicosity. Here, we examine the three-dimensional structure of microtubules in varicosities of a differentiated PC12 neural cell line using ultra-high voltage electron microscope tomography. Three-dimensional imaging showed that a part of the varicosities contained an accumulation of organelles that were separated from parallel microtubule arrays. Further detailed analysis using serial sections and whole-mount tomography revealed microtubules running in a spindle shape of swelling in some other types of varicosities. These electron tomographic results showed that the structural diversity and heterogeneity of microtubule organization supported the form of varicosities, suggesting that a different distribution pattern of microtubules in varicosities is crucial to the regulation of varicosities development.

  15. Laboratory-size three-dimensional x-ray microscope with Wolter type I mirror optics and an electron-impact water window x-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Ohsuka, Shinji, E-mail: ohsuka@crl.hpk.co.jp [Hamamatsu Photonics K.K., 5000 Hirakuchi, Hamakita-ku, Hamamatsu-City, 434-8601 (Japan); The Graduate School for the Creation of New Photonics Industries, 1955-1 Kurematsu-cho, Nishi-ku, Hamamatsu-City, 431-1202 (Japan); Ohba, Akira; Onoda, Shinobu; Nakamoto, Katsuhiro [Hamamatsu Photonics K.K., 5000 Hirakuchi, Hamakita-ku, Hamamatsu-City, 434-8601 (Japan); Nakano, Tomoyasu [Hamamatsu Photonics K.K., 5000 Hirakuchi, Hamakita-ku, Hamamatsu-City, 434-8601 (Japan); Ray-Focus Co. Ltd., 6009 Shinpara, Hamakita-ku, Hamamatsu-City, 434-0003 (Japan); Miyoshi, Motosuke; Soda, Keita; Hamakubo, Takao [Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan)

    2014-09-15

    We constructed a laboratory-size three-dimensional water window x-ray microscope that combines wide-field transmission x-ray microscopy with tomographic reconstruction techniques, and observed bio-medical samples to evaluate its applicability to life science research fields. It consists of a condenser and an objective grazing incidence Wolter type I mirror, an electron-impact type oxygen Kα x-ray source, and a back-illuminated CCD for x-ray imaging. A spatial resolution limit of around 1.0 line pairs per micrometer was obtained for two-dimensional transmission images, and 1-μm scale three-dimensional fine structures were resolved.

  16. Laboratory-size three-dimensional x-ray microscope with Wolter type I mirror optics and an electron-impact water window x-ray source.

    Science.gov (United States)

    Ohsuka, Shinji; Ohba, Akira; Onoda, Shinobu; Nakamoto, Katsuhiro; Nakano, Tomoyasu; Miyoshi, Motosuke; Soda, Keita; Hamakubo, Takao

    2014-09-01

    We constructed a laboratory-size three-dimensional water window x-ray microscope that combines wide-field transmission x-ray microscopy with tomographic reconstruction techniques, and observed bio-medical samples to evaluate its applicability to life science research fields. It consists of a condenser and an objective grazing incidence Wolter type I mirror, an electron-impact type oxygen Kα x-ray source, and a back-illuminated CCD for x-ray imaging. A spatial resolution limit of around 1.0 line pairs per micrometer was obtained for two-dimensional transmission images, and 1-μm scale three-dimensional fine structures were resolved.

  17. Uncertainty evaluation for three-dimensional scanning electron microscope reconstructions based on the stereo-pair technique

    DEFF Research Database (Denmark)

    Carli, Lorenzo; Genta, G; Cantatore, Angela

    2011-01-01

    3D-SEM is a method, based on the stereophotogrammetry technique, which obtains three-dimensional topographic reconstructions starting typically from two SEM images, called the stereo-pair. In this work, a theoretical uncertainty evaluation of the stereo-pair technique, according to GUM (Guide to ...

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

    KAUST Repository

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

    2010-01-01

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

  19. Uncertainty evaluation for three-dimensional scanning electron microscope reconstructions based on the stereo-pair technique

    International Nuclear Information System (INIS)

    Carli, L; Cantatore, A; De Chiffre, L; Genta, G; Barbato, G; Levi, R

    2011-01-01

    3D-SEM is a method, based on the stereophotogrammetry technique, which obtains three-dimensional topographic reconstructions starting typically from two SEM images, called the stereo-pair. In this work, a theoretical uncertainty evaluation of the stereo-pair technique, according to GUM (Guide to the Expression of Uncertainty in Measurement), was carried out, considering 3D-SEM reconstructions of a wire gauge with a reference diameter of 250 µm. Starting from the more commonly used tilting strategy, one based on the item rotation inside the SEM chamber was also adopted. The latter enables multiple-view reconstructions of the cylindrical item under consideration. Uncertainty evaluation was performed starting from a modified version of the Piazzesi equation, enabling the calculation of the z-coordinate from a given stereo-pair. The metrological characteristics of each input variable have been taken into account and a SEM stage calibration has been performed. Uncertainty tables for the cases of tilt and rotation were then produced, leading to the calculation of expanded uncertainty. For the case of rotation, the largest uncertainty contribution resulted to be the rotational angle; however, for the case of tilt it resulted to be the pixel size. A relative expanded uncertainty equal to 5% and 4% was obtained for the case of rotation and tilt, respectively

  20. Porcine pulmonary angiotensin I-converting enzyme--biochemical characterization and spatial arrangement of the N- and C-domains by three-dimensional electron microscopic reconstruction.

    Science.gov (United States)

    Chen, Hui-Ling; Lünsdorf, Heinrich; Hecht, Hans-Jürgen; Tsai, Hsin

    2010-08-01

    The somatic angiotensin I-converting enzyme (sACE; peptidyl-dipeptidase A; EC 3.4.15.1) was isolated from pig lung and purified to homogeneity. The purified enzyme has a molecular mass of about 180 kDa. Upon proteolytic cleavage, two approximately 90 kDa fragments were obtained and identified by amino-terminal sequence analysis as the N- and C-domains of sACE. Both purified domains were shown to be catalytically active. A 2.3 nm resolution model of sACE was obtained by three-dimensional electron microscopic reconstruction of negatively stained sACE particles, based on atomic X-ray data fitting. Our model shows for the first time the relative orientation of the sACE catalytically active domains and their spatial distance. (c) 2010 Elsevier Ltd. All rights reserved.

  1. Electron crystallography of three dimensional protein crystals

    NARCIS (Netherlands)

    Georgieva, Dilyana

    2008-01-01

    This thesis describes an investigation of the potential of electron diffraction for studying three dimensional sub-micro-crystals of proteins and pharmaceuticals. A prerequisite for using electron diffraction for structural studies is the predictable availability of tiny crystals. A method for

  2. Secondary signal imaging (SSI) electron tomography (SSI-ET): A new three-dimensional metrology for mesoscale specimens in transmission electron microscope.

    Science.gov (United States)

    Han, Chang Wan; Ortalan, Volkan

    2015-09-01

    We have demonstrated a new electron tomography technique utilizing the secondary signals (secondary electrons and backscattered electrons) for ultra thick (a few μm) specimens. The Monte Carlo electron scattering simulations reveal that the amount of backscattered electrons generated by 200 and 300keV incident electrons is a monotonic function of the sample thickness and this causes the thickness contrast satisfying the projection requirement for the tomographic reconstruction. Additional contribution of the secondary electrons emitted from the edges of the specimens enhances the visibility of the surface features. The acquired SSI tilt series of the specimen having mesoscopic dimensions are successfully reconstructed verifying that this new technique, so called the secondary signal imaging electron tomography (SSI-ET), can directly be utilized for 3D structural analysis of mesoscale structures. Published by Elsevier Ltd.

  3. Porcine pulmonary angiotensin I-converting enzyme--biochemical characterization and spatial arrangement of the N- and C-domains by three-dimensional electron microscopic reconstruction.

    OpenAIRE

    Chen, Hui-Ling; Lünsdorf, Heinrich; Hecht, Hans-Jürgen; Tsai, Hsin

    2010-01-01

    The somatic angiotensin I-converting enzyme (sACE; peptidyl-dipeptidase A; EC 3.4.15.1) was isolated from pig lung and purified to homogeneity. The purified enzyme has a molecular mass of about 180 kDa. Upon proteolytic cleavage, two approximately 90 kDa fragments were obtained and identified by amino-terminal sequence analysis as the N- and C-domains of sACE. Both purified domains were shown to be catalytically active. A 2.3 nm resolution model of sACE was obtained by three-dimensional elect...

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

    KAUST Repository

    De Jonge, Niels

    2010-01-18

    A three-dimensional (3D) reconstruction of the cytoskeleton and a clathrin-coated pit in mammalian cells has been achieved from a focal-series of images recorded in an aberration-corrected scanning transmission electron microscope (STEM). The specimen was a metallic replica of the biological structure comprising Pt nanoparticles 2-3 nm in diameter, with a high stability under electron beam radiation. The 3D dataset was processed by an automated deconvolution procedure. The lateral resolution was 1.1 nm, set by pixel size. Particles differing by only 10 nm in vertical position were identified as separate objects with greater than 20% dip in contrast between them. We refer to this value as the axial resolution of the deconvolution or reconstruction, the ability to recognize two objects, which were unresolved in the original dataset. The resolution of the reconstruction is comparable to that achieved by tilt-series transmission electron microscopy. However, the focal-series method does not require mechanical tilting and is therefore much faster. 3D STEM images were also recorded of the Golgi ribbon in conventional thin sections containing 3T3 cells with a comparable axial resolution in the deconvolved dataset. © 2010 Microscopy Society of America.

  5. Three-dimensional microscopic deformation measurements on cellular solids.

    Science.gov (United States)

    Genovese, K

    2016-07-01

    The increasing interest in small-scale problems demands novel experimental protocols providing dense sets of 3D deformation data of complex shaped microstructures. Obtaining such information is particularly significant for the study of natural and engineered cellular solids for which experimental data collected at macro scale and describing the global mechanical response provide only limited information on their function/structure relationship. Cellular solids, in fact, due their superior mechanical performances to a unique arrangement of the bulk material properties (i.e. anisotropy and heterogeneity) and cell structural features (i.e. pores shape, size and distribution) at the micro- and nano-scales. To address the need for full-field experimental data down to the cell level, this paper proposes a single-camera stereo-Digital Image Correlation (DIC) system that makes use of a wedge prism in series to a telecentric lens for performing surface shape and deformation measurements on microstructures in three dimensions. Although the system possesses a limited measurement volume (FOV~2.8×4.3mm(2), error-free DOF ~1mm), large surface areas of cellular samples can be accurately covered by employing a sequential image capturing scheme followed by an optimization-based mosaicing procedure. The basic principles of the proposed method together with the results of the benchmarking of its metrological performances and error analysis are here reported and discussed in detail. Finally, the potential utility of this method is illustrated with micro-resolution three-dimensional measurements on a 3D printed honeycomb and on a block sample of a Luffa sponge under compression. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Optical microscope for three-dimensional surface displacement and shape measurements at the microscale.

    Science.gov (United States)

    Xia, Shuman; Pan, Zhipeng; Zhang, Jingwen

    2014-07-15

    We report a novel optical microscope for full-field, noncontact measurements of three-dimensional (3D) surface deformation and topography at the microscale. The microscope system is based on a seamless integration of the diffraction-assisted image correlation (DAIC) method with fluorescent microscopy. We experimentally demonstrate the microscope's capability for 3D measurements with submicrometer spatial resolution and subpixel measurement accuracy.

  7. Three-dimensional simulations of free-electron laser physics

    International Nuclear Information System (INIS)

    McVey, B.D.

    1985-09-01

    A computer code has been developed to simulate three-dimensional free-electron laser physics. A mathematical formulation of the FEL equations is presented, and the numerical solution of the problem is described. Sample results from the computer code are discussed. 23 refs., 6 figs., 2 tabs

  8. Three Dimensional Imaging of Cold Atoms in a Magneto Optical Trap with a Light Field Microscope

    Science.gov (United States)

    2017-09-14

    with a Light Field Microscope Gordon E. Lott Follow this and additional works at: https://scholar.afit.edu/etd Part of the Atomic, Molecular and......https://scholar.afit.edu/etd/774 THREE-DIMENSIONAL IMAGING OF COLD ATOMS IN A MAGNETO-OPTICAL TRAP WITH A LIGHT FIELD MICROSCOPE DISSERTATION Gordon E

  9. Electron tomography, three-dimensional Fourier analysis and colour prediction of a three-dimensional amorphous biophotonic nanostructure

    Science.gov (United States)

    Shawkey, Matthew D.; Saranathan, Vinodkumar; Pálsdóttir, Hildur; Crum, John; Ellisman, Mark H.; Auer, Manfred; Prum, Richard O.

    2009-01-01

    Organismal colour can be created by selective absorption of light by pigments or light scattering by photonic nanostructures. Photonic nanostructures may vary in refractive index over one, two or three dimensions and may be periodic over large spatial scales or amorphous with short-range order. Theoretical optical analysis of three-dimensional amorphous nanostructures has been challenging because these structures are difficult to describe accurately from conventional two-dimensional electron microscopy alone. Intermediate voltage electron microscopy (IVEM) with tomographic reconstruction adds three-dimensional data by using a high-power electron beam to penetrate and image sections of material sufficiently thick to contain a significant portion of the structure. Here, we use IVEM tomography to characterize a non-iridescent, three-dimensional biophotonic nanostructure: the spongy medullary layer from eastern bluebird Sialia sialis feather barbs. Tomography and three-dimensional Fourier analysis reveal that it is an amorphous, interconnected bicontinuous matrix that is appropriately ordered at local spatial scales in all three dimensions to coherently scatter light. The predicted reflectance spectra from the three-dimensional Fourier analysis are more precise than those predicted by previous two-dimensional Fourier analysis of transmission electron microscopy sections. These results highlight the usefulness, and obstacles, of tomography in the description and analysis of three-dimensional photonic structures. PMID:19158016

  10. Propagation of three-dimensional electron-acoustic solitary waves

    International Nuclear Information System (INIS)

    Shalaby, M.; El-Sherif, L. S.; El-Labany, S. K.; Sabry, R.

    2011-01-01

    Theoretical investigation is carried out for understanding the properties of three-dimensional electron-acoustic waves propagating in magnetized plasma whose constituents are cold magnetized electron fluid, hot electrons obeying nonthermal distribution, and stationary ions. For this purpose, the hydrodynamic equations for the cold magnetized electron fluid, nonthermal electron density distribution, and the Poisson equation are used to derive the corresponding nonlinear evolution equation, Zkharov-Kuznetsov (ZK) equation, in the small- but finite- amplitude regime. The ZK equation is solved analytically and it is found that it supports both solitary and blow-up solutions. It is found that rarefactive electron-acoustic solitary waves strongly depend on the density and temperature ratios of the hot-to-cold electron species as well as the nonthermal electron parameter. Furthermore, there is a critical value for the nonthermal electron parameter, which decides whether the electron-acoustic solitary wave's amplitude is decreased or increased by changing various plasma parameters. Importantly, the change of the propagation angles leads to miss the balance between the nonlinearity and dispersion; hence, the localized pulses convert to explosive/blow-up pulses. The relevance of this study to the nonlinear electron-acoustic structures in the dayside auroral zone in the light of Viking satellite observations is discussed.

  11. Self-assembled three dimensional network designs for soft electronics.

    Science.gov (United States)

    Jang, Kyung-In; Li, Kan; Chung, Ha Uk; Xu, Sheng; Jung, Han Na; Yang, Yiyuan; Kwak, Jean Won; Jung, Han Hee; Song, Juwon; Yang, Ce; Wang, Ao; Liu, Zhuangjian; Lee, Jong Yoon; Kim, Bong Hoon; Kim, Jae-Hwan; Lee, Jungyup; Yu, Yongjoon; Kim, Bum Jun; Jang, Hokyung; Yu, Ki Jun; Kim, Jeonghyun; Lee, Jung Woo; Jeong, Jae-Woong; Song, Young Min; Huang, Yonggang; Zhang, Yihui; Rogers, John A

    2017-06-21

    Low modulus, compliant systems of sensors, circuits and radios designed to intimately interface with the soft tissues of the human body are of growing interest, due to their emerging applications in continuous, clinical-quality health monitors and advanced, bioelectronic therapeutics. Although recent research establishes various materials and mechanics concepts for such technologies, all existing approaches involve simple, two-dimensional (2D) layouts in the constituent micro-components and interconnects. Here we introduce concepts in three-dimensional (3D) architectures that bypass important engineering constraints and performance limitations set by traditional, 2D designs. Specifically, open-mesh, 3D interconnect networks of helical microcoils formed by deterministic compressive buckling establish the basis for systems that can offer exceptional low modulus, elastic mechanics, in compact geometries, with active components and sophisticated levels of functionality. Coupled mechanical and electrical design approaches enable layout optimization, assembly processes and encapsulation schemes to yield 3D configurations that satisfy requirements in demanding, complex systems, such as wireless, skin-compatible electronic sensors.

  12. Self-assembled three dimensional network designs for soft electronics

    Science.gov (United States)

    Jang, Kyung-In; Li, Kan; Chung, Ha Uk; Xu, Sheng; Jung, Han Na; Yang, Yiyuan; Kwak, Jean Won; Jung, Han Hee; Song, Juwon; Yang, Ce; Wang, Ao; Liu, Zhuangjian; Lee, Jong Yoon; Kim, Bong Hoon; Kim, Jae-Hwan; Lee, Jungyup; Yu, Yongjoon; Kim, Bum Jun; Jang, Hokyung; Yu, Ki Jun; Kim, Jeonghyun; Lee, Jung Woo; Jeong, Jae-Woong; Song, Young Min; Huang, Yonggang; Zhang, Yihui; Rogers, John A.

    2017-06-01

    Low modulus, compliant systems of sensors, circuits and radios designed to intimately interface with the soft tissues of the human body are of growing interest, due to their emerging applications in continuous, clinical-quality health monitors and advanced, bioelectronic therapeutics. Although recent research establishes various materials and mechanics concepts for such technologies, all existing approaches involve simple, two-dimensional (2D) layouts in the constituent micro-components and interconnects. Here we introduce concepts in three-dimensional (3D) architectures that bypass important engineering constraints and performance limitations set by traditional, 2D designs. Specifically, open-mesh, 3D interconnect networks of helical microcoils formed by deterministic compressive buckling establish the basis for systems that can offer exceptional low modulus, elastic mechanics, in compact geometries, with active components and sophisticated levels of functionality. Coupled mechanical and electrical design approaches enable layout optimization, assembly processes and encapsulation schemes to yield 3D configurations that satisfy requirements in demanding, complex systems, such as wireless, skin-compatible electronic sensors.

  13. Three-Dimensional Identification of Microorganisms Using a Digital Holographic Microscope

    Directory of Open Access Journals (Sweden)

    Ning Wu

    2013-01-01

    Full Text Available This paper reports a method for three-dimensional (3D analysis of shift-invariant pattern recognition and applies to holographic images digitally reconstructed from holographic microscopes. It is shown that the sequential application of a 2D filter to the plane-by-plane reconstruction of an optical field is exactly equivalent to the application of a more general filter with a 3D impulse response. We show that any 3D filters with arbitrary impulse response can be implemented in this way. This type of processing is applied to the two-class problem of distinguishing different types of bacteria. It is shown that the proposed technique can be easily implemented using a modified microscope to develop a powerful and cost-effective system with great potential for biological screening.

  14. Three-dimensional space charge distribution measurement in electron beam irradiated PMMA

    International Nuclear Information System (INIS)

    Imaizumi, Yoichi; Suzuki, Ken; Tanaka, Yasuhiro; Takada, Tatsuo

    1996-01-01

    The localized space charge distribution in electron beam irradiated PMMA was investigated using pulsed electroacoustic method. Using a conventional space charge measurement system, the distribution only in the depth direction (Z) can be measured assuming the charges distributed uniformly in the horizontal (X-Y) plane. However, it is difficult to measure the distribution of space charge accumulated in small area. Therefore, we have developed the new system to measure the three-dimensional space charge distribution using pulsed electroacoustic method. The system has a small electrode with a diameter of 1mm and a motor-drive X-Y stage to move the sample. Using the data measured at many points, the three-dimensional distribution were obtained. To estimate the system performance, the electron beam irradiated PMMA was used. The electron beam was irradiated from transmission electron microscope (TEM). The depth of injected electron was controlled using the various metal masks. The measurement results were compared with theoretically calculated values of electron range. (author)

  15. Three-dimensional rotation electron diffraction: software RED for automated data collection and data processing.

    Science.gov (United States)

    Wan, Wei; Sun, Junliang; Su, Jie; Hovmöller, Sven; Zou, Xiaodong

    2013-12-01

    Implementation of a computer program package for automated collection and processing of rotation electron diffraction (RED) data is described. The software package contains two computer programs: RED data collection and RED data processing. The RED data collection program controls the transmission electron microscope and the camera. Electron beam tilts at a fine step (0.05-0.20°) are combined with goniometer tilts at a coarse step (2.0-3.0°) around a common tilt axis, which allows a fine relative tilt to be achieved between the electron beam and the crystal in a large tilt range. An electron diffraction (ED) frame is collected at each combination of beam tilt and goniometer tilt. The RED data processing program processes three-dimensional ED data generated by the RED data collection program or by other approaches. It includes shift correction of the ED frames, peak hunting for diffraction spots in individual ED frames and identification of these diffraction spots as reflections in three dimensions. Unit-cell parameters are determined from the positions of reflections in three-dimensional reciprocal space. All reflections are indexed, and finally a list with hkl indices and intensities is output. The data processing program also includes a visualizer to view and analyse three-dimensional reciprocal lattices reconstructed from the ED frames. Details of the implementation are described. Data collection and data processing with the software RED are demonstrated using a calcined zeolite sample, silicalite-1. The structure of the calcined silicalite-1, with 72 unique atoms, could be solved from the RED data by routine direct methods.

  16. A versatile atomic force microscope for three-dimensional nanomanipulation and nanoassembly

    International Nuclear Information System (INIS)

    Xie Hui; Haliyo, Dogan Sinan; Regnier, Stephane

    2009-01-01

    A conventional atomic force microscope (AFM) has been successfully applied to manipulating nanoparticles (zero-dimensional), nanowires (one-dimensional) or nanotubes (one- or two-dimensional) by widely used pushing or pulling operations on a single surface. However, pick-and-place nanomanipulation in air is still a challenge. In this research, a modified AFM, called a three-dimensional (3D) manipulation force microscope (3DMFM), was developed to realize 3D nanomanipulation in air. This system consists of two individually actuated cantilevers with protruding tips that are facing each other, constructing a nanotweezer for the pick-and-place nanomanipulation. Before manipulation, one of the cantilevers is employed to position nano-objects and locate the tip of the other cantilever by image scanning. During the manipulation, these two cantilevers work collaboratively as a nanotweezer to grasp, transport and place the nano-objects with real-time force sensing. The manipulation capabilities of the nanotweezer were demonstrated by grabbing and manipulating silicon nanowires to build 3D nanowire crosses. 3D nanomanipulation and nanoassembly performed in air could become feasible through this newly developed 3DMFM.

  17. Three-dimensional observation of TiO2 nanostructures by electron tomography

    KAUST Repository

    Suh, Young Joon; Lu, Ning; Park, Seong Yong; Lee, Tae Hun; Lee, Sang Hoon; Cha, Dong Kyu; Lee, Min Gun; Huang, Jie; Kim, Sung Soo; Sohn, Byeong Hyeok; Kim, Geung Ho; Ko, Min Jae; Kim, Jiyoung; Kim, Moon J.

    2013-01-01

    Three-dimensional nanostructures of TiO2 related materials including nanotubes, electron acceptor materials in hybrid polymer solar cells, and working electrodes of dye sensitized solar cells (DSSCs) were visualized by electron tomography as well

  18. Atomic resolution three-dimensional electron diffraction microscopy

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  19. Three-dimensional nanostructure determination from a large diffraction data set recorded using scanning electron nanodiffraction

    Directory of Open Access Journals (Sweden)

    Yifei Meng

    2016-09-01

    Full Text Available A diffraction-based technique is developed for the determination of three-dimensional nanostructures. The technique employs high-resolution and low-dose scanning electron nanodiffraction (SEND to acquire three-dimensional diffraction patterns, with the help of a special sample holder for large-angle rotation. Grains are identified in three-dimensional space based on crystal orientation and on reconstructed dark-field images from the recorded diffraction patterns. Application to a nanocrystalline TiN thin film shows that the three-dimensional morphology of columnar TiN grains of tens of nanometres in diameter can be reconstructed using an algebraic iterative algorithm under specified prior conditions, together with their crystallographic orientations. The principles can be extended to multiphase nanocrystalline materials as well. Thus, the tomographic SEND technique provides an effective and adaptive way of determining three-dimensional nanostructures.

  20. A hybrid scanning force and light microscope for surface imaging and three-dimensional optical sectioning in differential interference contrast.

    Science.gov (United States)

    Stemmer, A

    1995-04-01

    The design of a scanned-cantilever-type force microscope is presented which is fully integrated into an inverted high-resolution video-enhanced light microscope. This set-up allows us to acquire thin optical sections in differential interference contrast (DIC) or polarization while the force microscope is in place. Such a hybrid microscope provides a unique platform to study how cell surface properties determine, or are affected by, the three-dimensional dynamic organization inside the living cell. The hybrid microscope presented in this paper has proven reliable and versatile for biological applications. It is the only instrument that can image a specimen by force microscopy and high-power DIC without having either to translate the specimen or to remove the force microscope. Adaptation of the design features could greatly enhance the suitability of other force microscopes for biological work.

  1. Three-dimensional electron-beam dose calculations

    International Nuclear Information System (INIS)

    Shiu, A.S.

    1988-01-01

    The MDAH pencil-beam algorithm developed by Hogstrom et al (1981) has been widely used in clinics for electron-beam dose calculations for radiotherapy treatment planning. The primary objective of this research was to address several deficiencies of that algorithm and to develop an enhanced version. Two enhancements were incorporated into the pencil-beam algorithm; one models fluence rather than planar fluence, and the other models the bremsstrahlung dose using measured beam data. Comparisons of the resulting calculated dose distributions with measured dose distributions for several test phantoms have been made. From these results it is concluded (1) that the fluence-based algorithm is more accurate to use for the dose calculation in an inhomogeneous slab phantom, and (2) the fluence-based calculation provides only a limited improvement to the accuracy the calculated dose in the region just downstream of the lateral edge of an inhomogeneity. A pencil-beam redefinition model was developed for the calculation of electron-beam dose distributions in three dimensions

  2. Ultrastructural changes following electron irradiation in three-dimensional culture of normal human dermal fibroblasts

    International Nuclear Information System (INIS)

    Han, Chunmao; Ishikura, Naotaka; Tsukada, Sadao

    1994-01-01

    The present study was designed to examine the effect of electron irradiation on fibroblasts and extracellular matrices electron-microscopically. The three-dimensional dermal fibroblast culture was exposed to one, 4 or 10 Gy of electron beams. One day after irradiation, fibroblasts were vacuolated in all irradiated groups and intercellular spaces were increased in a dose-dependent manner. Seven days later, intercellular spaces became dense in both one and 4 Gy groups, although they were still extremely increased in the 10 Gy group. The remaining fibroblasts were still activated in all groups. Thirty days after irradiation, myofibroblastic cells were scarcely observed, but extracellular fine fibrils and collagen fibrils were observed in all irradiated groups. The other ultrastructural findings were similar to those in the control group. In conclusion, electron beams damaged not only cells but also extracellular matrix. The extracellular matrix may be repaired by activated residual fibroblasts, resulting in the mixture of new and old collagen fibrils having different diamters. (N.K.)

  3. Three-dimensional phase-contrast X-ray microtomography with scanning–imaging X-ray microscope optics

    International Nuclear Information System (INIS)

    Takeuchi, Akihisa; Uesugi, Kentaro; Suzuki, Yoshio

    2013-01-01

    A novel three-dimensional X-ray microtomographic micro-imaging system which enables simultaneous measurement of differential phase contrast and absorption contrast has been developed. The optical system consists of a scanning microscope with one-dimensional focusing device and an imaging microscope with one-dimensional objective. A three-dimensional (3D) X-ray tomographic micro-imaging system has been developed. The optical system is based on a scanning–imaging X-ray microscope (SIXM) optics, which is a hybrid system consisting of a scanning microscope optics with a one-dimensional (1D) focusing (line-focusing) device and an imaging microscope optics with a 1D objective. In the SIXM system, each 1D dataset of a two-dimensional (2D) image is recorded independently. An object is illuminated with a line-focused beam. Positional information of the region illuminated by the line-focused beam is recorded with the 1D imaging microscope optics as line-profile data. By scanning the object with the line focus, 2D image data are obtained. In the same manner as for a scanning microscope optics with a multi-pixel detector, imaging modes such as phase contrast and absorption contrast can be arbitrarily configured after the image data acquisition. By combining a tomographic scan method and the SIXM system, quantitative 3D imaging is performed. Results of a feasibility study of the SIXM for 3D imaging are shown

  4. Development of Scanning-Imaging X-Ray Microscope for Quantitative Three-Dimensional Phase Contrast Microimaging

    International Nuclear Information System (INIS)

    Takeuchi, Akihisa; Suzuki, Yoshio; Uesugi, Kentaro

    2013-01-01

    A novel x-ray microscope system has been developed for the purpose of quantitative and sensitive three-dimensional (3D) phase-contrast x-ray microimaging. The optical system is a hybrid that consists of a scanning microscope optics with a one-dimensional (1D) focusing (line-focusing) device and an imaging microscope optics with a 1D objective. These two optics are orthogonally arranged regarding their common optical axis. Each is used for forming each dimension of two-dimensional (2D) image. The same data acquisition process as that of the scanning microscope system enables quantitative and sensitive x-ray imaging such as phase contrast and absorption contrast. Because a 2D image is measured with only 1D translation scan, much shorter measurement time than that of conventional scanning optics has been realized. By combining a computed tomography (CT) technique, some 3D CT application examples are demonstrated

  5. Three-dimensional modeling of electron quasiviscous dissipation in guide-field magnetic reconnection

    International Nuclear Information System (INIS)

    Hesse, Michael; Kuznetsova, Masha; Schindler, Karl; Birn, Joachim

    2005-01-01

    A numerical study of guide-field magnetic reconnection in a three-dimensional model is presented. Starting from an initial, perturbed, force-free current sheet, it is shown that reconnection develops to an almost translationally invariant state, where magnetic perturbations are aligned primarily along the main current flow direction. An analysis of guide-field and electron flow signatures indicates behavior that is very similar to earlier, albeit not three-dimensional, simulations. Furthermore, a detailed investigation of electron pressure nongyrotropies in the central diffusion region confirms the major role the associated dissipation process plays in establishing the reconnection electric field

  6. Thermal Investigation of Three-Dimensional GaN-on-SiC High Electron Mobility Transistors

    Science.gov (United States)

    2017-07-01

    University of L’Aquila, (2011). 23 Rao, H. & Bosman, G. Hot-electron induced defect generation in AlGaN/GaN high electron mobility transistors. Solid...AFRL-RY-WP-TR-2017-0143 THERMAL INVESTIGATION OF THREE- DIMENSIONAL GaN-on-SiC HIGH ELECTRON MOBILITY TRANSISTORS Qing Hao The University of Arizona...clarification memorandum dated 16 Jan 09. This report is available to the general public, including foreign nationals. Copies may be obtained from the

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

    NARCIS (Netherlands)

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

    2017-01-01

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

  8. Analytical Electron Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — The Titan 80-300 is a transmission electron microscope (TEM) equipped with spectroscopic detectors to allow chemical, elemental, and other analytical measurements to...

  9. Three-dimensional observation of TiO2 nanostructures by electron tomography

    KAUST Repository

    Suh, Young Joon

    2013-03-01

    Three-dimensional nanostructures of TiO2 related materials including nanotubes, electron acceptor materials in hybrid polymer solar cells, and working electrodes of dye sensitized solar cells (DSSCs) were visualized by electron tomography as well as TEM micrographs. The regions on the wall of TiO2 nanotubes where the streptavidins were attached were elucidated by electron tomogram analysis. The coverage of TiO2 nanotubes by streptavidin was also investigated. The TiO2 nanostructures in hybrid polymer solar cells made by sol-gel and atomic layer deposition (ALD) methods and the morphologies of pores between TiO2 particles in DSSCs were also observed by reconstructed three-dimensional images made by electron tomography. © 2012 Elsevier Ltd.

  10. Structural study of disordered SiC nanowires by three-dimensional rotation electron diffraction

    International Nuclear Information System (INIS)

    Li, Duan; Guo, Peng; Wan, Wei; Zou, Ji; Shen, Zhijian; Guzi de Moraes, Elisângela; Colombo, Paolo

    2014-01-01

    The structure of disordered SiC nanowires was studied by using the three-dimensional rotation electron diffraction (RED) technique. The streaks shown in the RED images indicated the stacking faults of the nanowire. High-resolution transmission electron microscopy imaging was employed to support the results from the RED data. It suggested that a 2H polytype is most possible for the nanowires. (paper)

  11. A three-dimensional X-ray diffraction microscope for deformation studies of polycrystals

    DEFF Research Database (Denmark)

    Fæster Nielsen, Søren; Lauridsen, E.M.; Juul Jensen, D.

    2001-01-01

    -dimensional X-ray diffraction (3DXRD) microscope installed at the European Synchrotron Radiation Facility in Grenoble provides a fast and non-destructive technique for mapping the embedded grains within thick samples in three dimensions. All essential features like the position, volume, orientation, stress...

  12. Optical Computed-Tomographic Microscope for Three-Dimensional Quantitative Histology

    Directory of Open Access Journals (Sweden)

    Ravil Chamgoulov

    2004-01-01

    Full Text Available A novel optical computed‐tomographic microscope has been developed allowing quantitative three‐dimensional (3D imaging and analysis of fixed pathological material. Rather than a conventional two‐dimensional (2D image, the instrument produces a 3D representation of fixed absorption‐stained material, from which quantitative histopathological features can be measured more accurately. The accurate quantification of these features is critically important in disease diagnosis and the clinical classification of cancer. The system consists of two high NA objective lenses, a light source, a digital spatial light modulator (DMD, by Texas Instrument, an x–y stage, and a CCD detector. The DMD, positioned at the back pupil‐plane of the illumination objective, is employed to illuminate the specimen with parallel rays at any desired angle. The system uses a modification of the convolution backprojection algorithm for reconstruction. In contrast to fluorescent images acquired by a confocal microscope, this instrument produces 3D images of absorption stained material. Microscopic 3D volume reconstructions of absorption‐stained cells have been demonstrated. Reconstructed 3D images of individual cells and tissue can be cut virtually with the distance between the axial slices less than 0.5 μm.

  13. Blood capillary length estimation from three-dimensional microscopic data by image analysis and stereology.

    Science.gov (United States)

    Kubínová, Lucie; Mao, Xiao Wen; Janáček, Jiří

    2013-08-01

    Studies of the capillary bed characterized by its length or length density are relevant in many biomedical studies. A reliable assessment of capillary length from two-dimensional (2D), thin histological sections is a rather difficult task as it requires physical cutting of such sections in randomized directions. This is often technically demanding, inefficient, or outright impossible. However, if 3D image data of the microscopic structure under investigation are available, methods of length estimation that do not require randomized physical cutting of sections may be applied. Two different rat brain regions were optically sliced by confocal microscopy and resulting 3D images processed by three types of capillary length estimation methods: (1) stereological methods based on a computer generation of isotropic uniform random virtual test probes in 3D, either in the form of spatial grids of virtual "slicer" planes or spherical probes; (2) automatic method employing a digital version of the Crofton relations using the Euler characteristic of planar sections of the binary image; and (3) interactive "tracer" method for length measurement based on a manual delineation in 3D of the axes of capillary segments. The presented methods were compared in terms of their practical applicability, efficiency, and precision.

  14. Scanning Auger Electron Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — A JEOL model 7830F field emission source, scanning Auger microscope.Specifications / Capabilities:Ultra-high vacuum (UHV), electron gun range from 0.1 kV to 25 kV,...

  15. Method for the determination of the three-dimensional structure of ultrashort relativistic electron bunches

    Energy Technology Data Exchange (ETDEWEB)

    Geloni, Gianluca; Ilinski, Petr; Saldin, Evgeni; Schneidmiller, Evgeni; Yurkov, Mikhail

    2009-05-15

    We describe a novel technique to characterize ultrashort electron bunches in Xray Free-Electron Lasers. Namely, we propose to use coherent Optical Transition Radiation to measure three-dimensional (3D) electron density distributions. Our method relies on the combination of two known diagnostics setups, an Optical Replica Synthesizer (ORS) and an Optical Transition Radiation (OTR) imager. Electron bunches are modulated at optical wavelengths in the ORS setup.When these electron bunches pass through a metal foil target, coherent radiation pulses of tens MW power are generated. It is thereafter possible to exploit advantages of coherent imaging techniques, such as direct imaging, diffractive imaging, Fourier holography and their combinations. The proposed method opens up the possibility of real-time, wavelength-limited, single-shot 3D imaging of an ultrashort electron bunch. (orig.)

  16. Three-dimensional hot electron photovoltaic device with vertically aligned TiO2 nanotubes.

    Science.gov (United States)

    Goddeti, Kalyan C; Lee, Changhwan; Lee, Young Keun; Park, Jeong Young

    2018-05-09

    Titanium dioxide (TiO 2 ) nanotubes with vertically aligned array structures show substantial advantages in solar cells as an electron transport material that offers a large surface area where charges travel linearly along the nanotubes. Integrating this one-dimensional semiconductor material with plasmonic metals to create a three-dimensional plasmonic nanodiode can influence solar energy conversion by utilizing the generated hot electrons. Here, we devised plasmonic Au/TiO 2 and Ag/TiO 2 nanodiode architectures composed of TiO 2 nanotube arrays for enhanced photon absorption, and for the subsequent generation and capture of hot carriers. The photocurrents and incident photon to current conversion efficiencies (IPCE) were obtained as a function of photon energy for hot electron detection. We observed enhanced photocurrents and IPCE using the Ag/TiO 2 nanodiode. The strong plasmonic peaks of the Au and Ag from the IPCE clearly indicate an enhancement of the hot electron flux resulting from the presence of surface plasmons. The calculated electric fields and the corresponding absorbances of the nanodiode using finite-difference time-domain simulation methods are also in good agreement with the experimental results. These results show a unique strategy of combining a hot electron photovoltaic device with a three-dimensional architecture, which has the clear advantages of maximizing light absorption and a metal-semiconductor interface area.

  17. THE MARGINAL FIT OF MILLED-CERAMIC INLAYS – A COMPARATIVE THREE DIMENSIONAL AND MICROSCOPIC RESEARCH

    Directory of Open Access Journals (Sweden)

    Sorana BACIU

    2017-03-01

    Full Text Available Objective: The main goal of the present study is to compare two methods for evaluating the marginal fit of fixed prosthetic restorations. For this purpose we used a milled ceramic material, out of which we obtained class I inlays. The marginal gap was analyzed using micro CT and electronic microscopy. Materials and methods: After extraction of four caries-free mandibular first molars, first class inlay cavities were prepared. The marginal gap was analyzed circumferentially at the occlusal margin using a Bruker micro CT, by measuring the distance at the occlusal limit of the cavities, between the restoration and the tooth in several points for every surface of each tooth before cementing. For the second method SEM technology was used, and measurements were made at the occlusal limit of the cavities, between the restoration and the tooth in 50 microns steps. The data were compared with One–way ANOVA with Tukey’s Multiple Comparison Test performed using 5.00 for Windows (GraphPad Prism 5.00 Software, San Diego, California USA. Results and discussion: For both methods we obtained clinical acceptable values of the marginal gap for the milled ceramic inlays. The null hypothesis was rejected. We obtained statistical significant differences of the measured gaps using the two above mentioned methods. Conclusions: Both evaluation methods are reliable for measuring the marginal gap of fixed prosthetic restorations, each method having specific indications, advantages and disadvantages. They offer indispensable information which lead to improvement of the restorative treatments.

  18. Electronic transport on the spatial structure of the protein: Three-dimensional lattice model

    International Nuclear Information System (INIS)

    Sarmento, R.G.; Frazão, N.F.; Macedo-Filho, A.

    2017-01-01

    Highlights: • The electronic transport on the structure of the three-dimensional lattice model of the protein is studied. • The signing of the current–voltage is directly affected by permutations of the weak bonds in the structure. • Semiconductor behave of the proteins suggest a potential application in the development of novel biosensors. - Abstract: We report a numerical analysis of the electronic transport in protein chain consisting of thirty-six standard amino acids. The protein chains studied have three-dimensional structure, which can present itself in three distinct conformations and the difference consist in the presence or absence of thirteen hydrogen-bondings. Our theoretical method uses an electronic tight-binding Hamiltonian model, appropriate to describe the protein segments modeled by the amino acid chain. We note that the presence and the permutations between weak bonds in the structure of proteins are directly related to the signing of the current–voltage. Furthermore, the electronic transport depends on the effect of temperature. In addition, we have found a semiconductor behave in the models investigated and it suggest a potential application in the development of novel biosensors for molecular diagnostics.

  19. Electronic transport on the spatial structure of the protein: Three-dimensional lattice model

    Energy Technology Data Exchange (ETDEWEB)

    Sarmento, R.G. [Departamento de Ciências Biológicas, Universidade Federal do Piauí, 64800-000 Floriano, PI (Brazil); Frazão, N.F. [Centro de Educação e Saúde, Universidade Federal de Campina Grande, 581750-000 Cuité, PB (Brazil); Macedo-Filho, A., E-mail: amfilho@gmail.com [Campus Prof. Antonio Geovanne Alves de Sousa, Universidade Estadual do Piauí, 64260-000 Piripiri, PI (Brazil)

    2017-01-30

    Highlights: • The electronic transport on the structure of the three-dimensional lattice model of the protein is studied. • The signing of the current–voltage is directly affected by permutations of the weak bonds in the structure. • Semiconductor behave of the proteins suggest a potential application in the development of novel biosensors. - Abstract: We report a numerical analysis of the electronic transport in protein chain consisting of thirty-six standard amino acids. The protein chains studied have three-dimensional structure, which can present itself in three distinct conformations and the difference consist in the presence or absence of thirteen hydrogen-bondings. Our theoretical method uses an electronic tight-binding Hamiltonian model, appropriate to describe the protein segments modeled by the amino acid chain. We note that the presence and the permutations between weak bonds in the structure of proteins are directly related to the signing of the current–voltage. Furthermore, the electronic transport depends on the effect of temperature. In addition, we have found a semiconductor behave in the models investigated and it suggest a potential application in the development of novel biosensors for molecular diagnostics.

  20. Three-dimensional electron microscopy of macromolecular assemblies: visualization of biological molecules in their native state

    National Research Council Canada - National Science Library

    Frank, J

    2006-01-01

    ... Clusters 2.8 Support Grids 33 33 3 Principle of Image Formation in the Transmission Electron Microscope 34 3.1 Introduction 34 3.2 The Weak-Phase Object Approximation 35 3.3 The Contrast Transfer...

  1. Three-dimensional structural analysis of eukaryotic flagella/cilia by electron cryo-tomography

    International Nuclear Information System (INIS)

    Bui, Khanh Huy; Pigino, Gaia; Ishikawa, Takashi

    2011-01-01

    Based on the molecular architecture revealed by electron cryo-tomography, the mechanism of the bending motion of eukaryotic flagella/cilia is discussed. Electron cryo-tomography is a potential approach to analyzing the three-dimensional conformation of frozen hydrated biological macromolecules using electron microscopy. Since projections of each individual object illuminated from different orientations are merged, electron tomography is capable of structural analysis of such heterogeneous environments as in vivo or with polymorphism, although radiation damage and the missing wedge are severe problems. Here, recent results on the structure of eukaryotic flagella, which is an ATP-driven bending organelle, from green algae Chlamydomonas are presented. Tomographic analysis reveals asymmetric molecular arrangements, especially that of the dynein motor proteins, in flagella, giving insight into the mechanism of planar asymmetric bending motion. Methodological challenges to obtaining higher-resolution structures from this technique are also discussed

  2. Electron and ion heating by whistler turbulence: Three-dimensional particle-in-cell simulations

    International Nuclear Information System (INIS)

    Hughes, R. Scott; Gary, S. Peter; Wang, Joseph

    2014-01-01

    Three-dimensional particle-in-cell simulations of decaying whistler turbulence are carried out on a collisionless, homogeneous, magnetized, electron-ion plasma model. In addition, the simulations use an initial ensemble of relatively long wavelength whistler modes with a broad range of initial propagation directions with an initial electron beta β e = 0.05. The computations follow the temporal evolution of the fluctuations as they cascade into broadband turbulent spectra at shorter wavelengths. Three simulations correspond to successively larger simulation boxes and successively longer wavelengths of the initial fluctuations. The computations confirm previous results showing electron heating is preferentially parallel to the background magnetic field B o , and ion heating is preferentially perpendicular to B o . The new results here are that larger simulation boxes and longer initial whistler wavelengths yield weaker overall dissipation, consistent with linear dispersion theory predictions of decreased damping, stronger ion heating, consistent with a stronger ion Landau resonance, and weaker electron heating

  3. Designing electronic anisotropy of three-dimensional carbon allotropes for the all-carbon device

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Li-Chun, E-mail: xulichun@tyut.edu.cn; Song, Xian-Jiang; Yang, Zhi; Li, Xiu-Yan [College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China); Wang, Ru-Zhi; Yan, Hui [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China)

    2015-07-13

    Extending two-dimensional (2D) graphene nanosheets to a three-dimensional (3D) network can enhance the design of all-carbon electronic devices. Based on the great diversity of carbon atomic bonding, we have constructed four superlattice-type carbon allotrope candidates, containing sp{sup 2}-bonding transport channels and sp{sup 3}-bonding insulating layers, using density functional theory. It was demonstrated through systematic simulations that the ultra-thin insulating layer with only three-atom thickness can switch off the tunneling transport and isolate the electronic connection between the adjacent graphene strips, and these alternating perpendicular strips also extend the electron road from 2D to 3D. Designing electronic anisotropy originates from the mutually perpendicular π bonds and the rare partial charge density of the corresponding carriers in insulating layers. Our results indicate the possibility of producing custom-designed 3D all-carbon devices with building blocks of graphene and diamond.

  4. Three-dimensional visualization of forming Hepatitis C virus-like particles by electron-tomography

    Energy Technology Data Exchange (ETDEWEB)

    Badia-Martinez, Daniel; Peralta, Bibiana [Structural Biology Unit, CIC bioGUNE, CIBERehd, 48160 Derio (Spain); Andres, German; Guerra, Milagros [Electron Microscopy Unit, Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Campus Cantoblanco, 28049 Madrid (Spain); Gil-Carton, David [Structural Biology Unit, CIC bioGUNE, CIBERehd, 48160 Derio (Spain); Abrescia, Nicola G.A., E-mail: nabrescia@cicbiogune.es [Structural Biology Unit, CIC bioGUNE, CIBERehd, 48160 Derio (Spain); IKERBASQUE, Basque Foundation for Science, 48011 Bilbao (Spain)

    2012-09-01

    Hepatitis C virus infects almost 170 million people per year but its assembly pathway, architecture and the structures of its envelope proteins are poorly understood. Using electron tomography of plastic-embedded sections of insect cells, we have visualized the morphogenesis of recombinant Hepatitis C virus-like particles. Our data provide a three-dimensional sketch of viral assembly at the endoplasmic reticulum showing different budding stages and contiguity of buds. This latter phenomenon could play an important role during the assembly of wt-HCV and explain the size-heterogeneity of its particles.

  5. Three-dimensional visualization of forming Hepatitis C virus-like particles by electron-tomography

    International Nuclear Information System (INIS)

    Badia-Martinez, Daniel; Peralta, Bibiana; Andrés, German; Guerra, Milagros; Gil-Carton, David; Abrescia, Nicola G.A.

    2012-01-01

    Hepatitis C virus infects almost 170 million people per year but its assembly pathway, architecture and the structures of its envelope proteins are poorly understood. Using electron tomography of plastic-embedded sections of insect cells, we have visualized the morphogenesis of recombinant Hepatitis C virus-like particles. Our data provide a three-dimensional sketch of viral assembly at the endoplasmic reticulum showing different budding stages and contiguity of buds. This latter phenomenon could play an important role during the assembly of wt-HCV and explain the size-heterogeneity of its particles.

  6. Three-dimensional characterization of pigment dispersion in dried paint films using focused ion beam-scanning electron microscopy.

    Science.gov (United States)

    Lin, Jui-Ching; Heeschen, William; Reffner, John; Hook, John

    2012-04-01

    The combination of integrated focused ion beam-scanning electron microscope (FIB-SEM) serial sectioning and imaging techniques with image analysis provided quantitative characterization of three-dimensional (3D) pigment dispersion in dried paint films. The focused ion beam in a FIB-SEM dual beam system enables great control in slicing paints, and the sectioning process can be synchronized with SEM imaging providing high quality serial cross-section images for 3D reconstruction. Application of Euclidean distance map and ultimate eroded points image analysis methods can provide quantitative characterization of 3D particle distribution. It is concluded that 3D measurement of binder distribution in paints is effective to characterize the order of pigment dispersion in dried paint films.

  7. Photogrammetry of the three-dimensional shape and texture of a nanoscale particle using scanning electron microscopy and free software

    International Nuclear Information System (INIS)

    Gontard, Lionel C.; Schierholz, Roland; Yu, Shicheng; Cintas, Jesús; Dunin-Borkowski, Rafal E.

    2016-01-01

    We apply photogrammetry in a scanning electron microscope (SEM) to study the three-dimensional shape and surface texture of a nanoscale LiTi_2(PO_4)_3 particle. We highlight the fact that the technique can be applied non-invasively in any SEM using free software (freeware) and does not require special sample preparation. Three-dimensional information is obtained in the form of a surface mesh, with the texture of the sample stored as a separate two-dimensional image (referred to as a UV Map). The mesh can be used to measure parameters such as surface area, volume, moment of inertia and center of mass, while the UV map can be used to study the surface texture using conventional image processing techniques. We also illustrate the use of 3D printing to visualize the reconstructed model. - Highlights: • 3D shape and surface texture of a nanoscale LiTi_2(PO_4)_3 particle. • The technique can be applied non-invasively in any SEM using freeware software. • The mesh can be used to measure parameters such as surface area, volume, moment of inertia and center of mass. • The UV map can be processed using 2D image processing software.

  8. Photogrammetry of the three-dimensional shape and texture of a nanoscale particle using scanning electron microscopy and free software

    Energy Technology Data Exchange (ETDEWEB)

    Gontard, Lionel C., E-mail: lionelcg@gmail.com [Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica, Universidad de Cádiz, Puerto Real 11510 (Spain); Faico PCT Cartuja. Edif. TI Marie Curie, C/ Leonardo da Vinci 18, 4a Planta, 41092 Sevilla (Spain); Schierholz, Roland; Yu, Shicheng [Institute of Energy and Climate Research, Fundamental Electrochemistry (IEK-9), Forschungszentrum Jülich, D-52425 Jülich (Germany); Cintas, Jesús [Servicio de Microscopía Centro de Investigación, Tecnología e Innovación (CITIUS), Universidad de Sevilla, Av. Reina Mercedes 4b, 41012 Sevilla (Spain); Dunin-Borkowski, Rafal E. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany)

    2016-10-15

    We apply photogrammetry in a scanning electron microscope (SEM) to study the three-dimensional shape and surface texture of a nanoscale LiTi{sub 2}(PO{sub 4}){sub 3} particle. We highlight the fact that the technique can be applied non-invasively in any SEM using free software (freeware) and does not require special sample preparation. Three-dimensional information is obtained in the form of a surface mesh, with the texture of the sample stored as a separate two-dimensional image (referred to as a UV Map). The mesh can be used to measure parameters such as surface area, volume, moment of inertia and center of mass, while the UV map can be used to study the surface texture using conventional image processing techniques. We also illustrate the use of 3D printing to visualize the reconstructed model. - Highlights: • 3D shape and surface texture of a nanoscale LiTi{sub 2}(PO{sub 4}){sub 3} particle. • The technique can be applied non-invasively in any SEM using freeware software. • The mesh can be used to measure parameters such as surface area, volume, moment of inertia and center of mass. • The UV map can be processed using 2D image processing software.

  9. Direct-write three-dimensional nanofabrication of nanopyramids and nanocones on Si by nanotumefaction using a helium ion microscope

    Science.gov (United States)

    Zhang, L.; Heinig, N. F.; Bazargan, S.; Abd-Ellah, M.; Moghimi, N.; Leung, K. T.

    2015-06-01

    The recently commercialized helium ion microscope (HIM) has already demonstrated its outstanding imaging capabilities in terms of resolution, surface sensitivity, depth of field and ease of charge compensation. Here, we show its exceptional patterning capabilities by fabricating dense lines and three-dimensional (3D) nanostructures on a Si substrate. Small focusing spot size and confined ion-Si interaction volume of a high-energy helium ion beam account for the high resolution in HIM patterning. We demonstrate that a set of resolvable parallel lines with a half pitch as small as 3.5 nm can be achieved. During helium ion bombardment of the Si surface, implantation outperforms milling due to the small mass of the helium ions, which produces tumefaction instead of depression in the Si surface. The Si surface tumefaction is the result of different kinetic processes including diffusion, coalescence and nanobubble formation of the implanted ions, and is found to be very stable structurally at room temperature. Under appropriate conditions, a linear dependence of the surface swollen height on the ion doses can be observed. This relation has enabled us to fabricate nanopyramids and nanocones, thus demonstrating that HIM patterning provides a new ‘bottom-up’ approach to fabricate 3D nanostructures. This surface tumefaction method is direct, both positioning and height accurate, and free of resist, etch, mode and precursor, and it promises new applications in nanoimprint mold fabrication and photomask clear defect reparation.

  10. Direct-write three-dimensional nanofabrication of nanopyramids and nanocones on Si by nanotumefaction using a helium ion microscope

    International Nuclear Information System (INIS)

    Zhang, L; Heinig, N F; Bazargan, S; Abd-Ellah, M; Moghimi, N; Leung, K T

    2015-01-01

    The recently commercialized helium ion microscope (HIM) has already demonstrated its outstanding imaging capabilities in terms of resolution, surface sensitivity, depth of field and ease of charge compensation. Here, we show its exceptional patterning capabilities by fabricating dense lines and three-dimensional (3D) nanostructures on a Si substrate. Small focusing spot size and confined ion–Si interaction volume of a high-energy helium ion beam account for the high resolution in HIM patterning. We demonstrate that a set of resolvable parallel lines with a half pitch as small as 3.5 nm can be achieved. During helium ion bombardment of the Si surface, implantation outperforms milling due to the small mass of the helium ions, which produces tumefaction instead of depression in the Si surface. The Si surface tumefaction is the result of different kinetic processes including diffusion, coalescence and nanobubble formation of the implanted ions, and is found to be very stable structurally at room temperature. Under appropriate conditions, a linear dependence of the surface swollen height on the ion doses can be observed. This relation has enabled us to fabricate nanopyramids and nanocones, thus demonstrating that HIM patterning provides a new ‘bottom-up’ approach to fabricate 3D nanostructures. This surface tumefaction method is direct, both positioning and height accurate, and free of resist, etch, mode and precursor, and it promises new applications in nanoimprint mold fabrication and photomask clear defect reparation. (paper)

  11. Scanning electron microscope

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    The principle underlying the design of the scanning electron microscope (SEM), the design and functioning of SEM are described. Its applications in the areas of microcircuitry and materials science are outlined. The development of SEM in India is reviewed. (M.G.B.)

  12. Electron microscope studies

    International Nuclear Information System (INIS)

    Crewe, A.V.; Kapp, O.H.

    1992-01-01

    This is a report covering the research performed in the Crewe laboratory between 1964 and 1992. Because of limitations of space we have provided relatively brief summaries of the major research directions of the facility during these years. A complete bibliography has been included and we have referenced groups of pertinent publications at the beginning of each section. This report summarizes our efforts to develop better electron microscopes and chronicles many of the experimental programs, in materials science and biology, that acted both as a stimulus to better microscope design and also as a testing ground for many instrumental innovations

  13. Electron microscope studies

    Energy Technology Data Exchange (ETDEWEB)

    Crewe, A.V.; Kapp, O.H.

    1992-07-01

    This is a report covering the research performed in the Crewe laboratory between 1964 and 1992. Because of limitations of space we have provided relatively brief summaries of the major research directions of the facility during these years. A complete bibliography has been included and we have referenced groups of pertinent publications at the beginning of each section. This report summarizes our efforts to develop better electron microscopes and chronicles many of the experimental programs, in materials science and biology, that acted both as a stimulus to better microscope design and also as a testing ground for many instrumental innovations.

  14. Approximation for discrete Fourier transform and application in study of three-dimensional interacting electron gas.

    Science.gov (United States)

    Yan, Xin-Zhong

    2011-07-01

    The discrete Fourier transform is approximated by summing over part of the terms with corresponding weights. The approximation reduces significantly the requirement for computer memory storage and enhances the numerical computation efficiency with several orders without losing accuracy. As an example, we apply the algorithm to study the three-dimensional interacting electron gas under the renormalized-ring-diagram approximation where the Green's function needs to be self-consistently solved. We present the results for the chemical potential, compressibility, free energy, entropy, and specific heat of the system. The ground-state energy obtained by the present calculation is compared with the existing results of Monte Carlo simulation and random-phase approximation.

  15. A three-dimensional polarization domain retrieval method from electron diffraction data

    International Nuclear Information System (INIS)

    Pennington, Robert S.; Koch, Christoph T.

    2015-01-01

    We present an algorithm for retrieving three-dimensional domains of picometer-scale shifts in atomic positions from electron diffraction data, and apply it to simulations of ferroelectric polarization in BaTiO 3 . Our algorithm successfully and correctly retrieves polarization domains in which the Ti atom positions differ by less than 3 pm (0.4% of the unit cell diagonal distance) with 5 and 10 nm depth resolution along the beam direction, and we also retrieve unit cell strain, corresponding to tetragonal-to-cubic unit cell distortions, for 10 nm domains. Experimental applicability is also discussed. - Highlights: • We show a retrieval method for ferroelectric polarization from TEM diffraction data. • Simulated strain and polarization variations along the beam direction are retrieved. • This method can be used for 3D strain and polarization mapping without specimen tilt

  16. Three-dimensional analysis of harmonic generation in high-gain free-electron lasers

    International Nuclear Information System (INIS)

    Huang, Zhirong; Kim, Kwang-Je

    2000-01-01

    In a high-gain free-electron laser (FEL) employing a planar undulator, strong bunching at the fundamental wavelength can drive substantial bunching and power levels at the harmonic frequencies. In this paper we investigate the three-dimensional evolution of harmonic radiation based on the coupled Maxwell-Klimontovich equations that take into account nonlinear harmonic interactions. Each harmonic field is a sum of a linear amplification term and a term driven by nonlinear harmonic interactions. After a certain stage of exponential growth, the dominant nonlinear term is determined by interactions of the lower nonlinear harmonics and the fundamental radiation. As a result, the gain length, transverse profile, and temporal structure of the first few harmonics are eventually governed by those of the fundamental. Transversely coherent third-harmonic radiation power is found to approach 1% of the fundamental power level for current high-gain FEL projects

  17. Three-dimensional analysis of free-electron laser performance using brightness scaled variables

    Directory of Open Access Journals (Sweden)

    M. Gullans

    2008-06-01

    Full Text Available A three-dimensional analysis of radiation generation in a free-electron laser (FEL is performed in the small signal regime. The analysis includes beam conditioning, harmonic generation, flat beams, and a new scaling of the FEL equations using the six-dimensional beam brightness. The six-dimensional beam brightness is an invariant under Liouvillian flow; therefore, any nondissipative manipulation of the phase space, performed, for example, in order to optimize FEL performance, must conserve this brightness. This scaling is more natural than the commonly used scaling with the one-dimensional growth rate. The brightness-scaled equations allow for the succinct characterization of the optimal FEL performance under various additional constraints. The analysis allows for the simple evaluation of gain enhancement schemes based on beam phase space manipulations such as emittance exchange and conditioning. An example comparing the gain in the first and third harmonics of round or flat and conditioned or unconditioned beams is presented.

  18. Three-dimensional simulations of an XUV free-electron laser

    International Nuclear Information System (INIS)

    Goldstein, J.C.; McVey, B.D.; Newnam, B.E.

    1985-01-01

    Operation of free-electron lasers (FEL) at long optical wavelengths (greater than or equal to 600 nm) has now been successfully demonstrated at several laboratories. To operate an FEL at shorter wavelengths imposes constraints on the brightness of the electron beam which are difficult to achieve. Until recently, it was perceived that only an electron storage ring could satisfy these beam requirements. However, our previous 1-D theoretical calculations revealed that modest improvements in the emittance available from rf-linear accelerators would be sufficient to allow operation of an FEL in the XUV spectral range (greater than or equal to 50 nm). We shall present new theoretical results for the design of a linac-driven XUV FEL derived from an improved simulation model. The model is fully three-dimensional in its treatment of the undulator magnetic field, the optical radiation field, and the motion of electrons in a finite-emittance beam. Furthermore, the model computes self-consistently the motion of the electrons and the amplification, diffraction, and the refraction of the light within the undulator magnet. Propagation of the optical beam and reflection at the mirrors of the optical resonator are incorporated in the model so that a complete laser oscillator solution can be generated. The computed performance parameters of a particular XUV FEL oscillator design will be compared with the output of synchrotron radiation sources. 26 refs., 8 figs

  19. Three Dimensional Dirac Semimetals

    Science.gov (United States)

    Zaheer, Saad

    2014-03-01

    Dirac points on the Fermi surface of two dimensional graphene are responsible for its unique electronic behavior. One can ask whether any three dimensional materials support similar pseudorelativistic physics in their bulk electronic spectra. This possibility has been investigated theoretically and is now supported by two successful experimental demonstrations reported during the last year. In this talk, I will summarize the various ways in which Dirac semimetals can be realized in three dimensions with primary focus on a specific theory developed on the basis of representations of crystal spacegroups. A three dimensional Dirac (Weyl) semimetal can appear in the presence (absence) of inversion symmetry by tuning parameters to the phase boundary separating a bulk insulating and a topological insulating phase. More generally, we find that specific rules governing crystal symmetry representations of electrons with spin lead to robust Dirac points at high symmetry points in the Brillouin zone. Combining these rules with microscopic considerations identifies six candidate Dirac semimetals. Another method towards engineering Dirac semimetals involves combining crystal symmetry and band inversion. Several candidate materials have been proposed utilizing this mechanism and one of the candidates has been successfully demonstrated as a Dirac semimetal in two independent experiments. Work carried out in collaboration with: Julia A. Steinberg, Steve M. Young, J.C.Y. Teo, C.L. Kane, E.J. Mele and Andrew M. Rappe.

  20. Three-dimensional simulation of thermal harmonic lasing free electron laser with detuning of the fundamental

    Science.gov (United States)

    Salehi, E.; Maraghechi, B.; Mirian, N. S.

    2016-03-01

    Detuning of the fundamental is a way to enhance harmonic generation. By this method, the wiggler is composed of two segments in such a way that the fundamental resonance of the second segment to coincide with the third harmonic of the first segment of the wiggler to generate extreme ultraviolet radiation and x-ray emission. A set of coupled, nonlinear, and first-order differential equations in three dimensions describing the evolution of the electron trajectories and the radiation field with warm beam is solved numerically by CYRUS 3D code in the steady-state for two models (1) seeded free electron laser (FEL) and (2) shot noise on the electron beam (self-amplified spontaneous emission FEL). Thermal effects in the form of longitudinal velocity spread are considered. Three-dimensional simulation describes self-consistently the longitudinal spatial dependence of radiation waists, curvatures, and amplitudes together with the evaluation of the electron beam. The evolutions of the transverse modes are investigated for the fundamental resonance and the third harmonic. Also, the effective modes of the third harmonic are studied. In this paper, we found that detuning of the fundamental with shot noise gives more optimistic result than the seeded FEL.

  1. Three-dimensional simulation of thermal harmonic lasing free electron laser with detuning of the fundamental

    International Nuclear Information System (INIS)

    Salehi, E.; Maraghechi, B.; Mirian, N. S.

    2016-01-01

    Detuning of the fundamental is a way to enhance harmonic generation. By this method, the wiggler is composed of two segments in such a way that the fundamental resonance of the second segment to coincide with the third harmonic of the first segment of the wiggler to generate extreme ultraviolet radiation and x-ray emission. A set of coupled, nonlinear, and first-order differential equations in three dimensions describing the evolution of the electron trajectories and the radiation field with warm beam is solved numerically by CYRUS 3D code in the steady-state for two models (1) seeded free electron laser (FEL) and (2) shot noise on the electron beam (self-amplified spontaneous emission FEL). Thermal effects in the form of longitudinal velocity spread are considered. Three-dimensional simulation describes self-consistently the longitudinal spatial dependence of radiation waists, curvatures, and amplitudes together with the evaluation of the electron beam. The evolutions of the transverse modes are investigated for the fundamental resonance and the third harmonic. Also, the effective modes of the third harmonic are studied. In this paper, we found that detuning of the fundamental with shot noise gives more optimistic result than the seeded FEL.

  2. Uniform electron gases. III. Low-density gases on three-dimensional spheres

    Energy Technology Data Exchange (ETDEWEB)

    Agboola, Davids; Knol, Anneke L.; Gill, Peter M. W., E-mail: peter.gill@anu.edu.au; Loos, Pierre-François, E-mail: pf.loos@anu.edu.au [Research School of Chemistry, Australian National University, Canberra ACT 2601 (Australia)

    2015-08-28

    By combining variational Monte Carlo (VMC) and complete-basis-set limit Hartree-Fock (HF) calculations, we have obtained near-exact correlation energies for low-density same-spin electrons on a three-dimensional sphere (3-sphere), i.e., the surface of a four-dimensional ball. In the VMC calculations, we compare the efficacies of two types of one-electron basis functions for these strongly correlated systems and analyze the energy convergence with respect to the quality of the Jastrow factor. The HF calculations employ spherical Gaussian functions (SGFs) which are the curved-space analogs of Cartesian Gaussian functions. At low densities, the electrons become relatively localized into Wigner crystals, and the natural SGF centers are found by solving the Thomson problem (i.e., the minimum-energy arrangement of n point charges) on the 3-sphere for various values of n. We have found 11 special values of n whose Thomson sites are equivalent. Three of these are the vertices of four-dimensional Platonic solids — the hyper-tetrahedron (n = 5), the hyper-octahedron (n = 8), and the 24-cell (n = 24) — and a fourth is a highly symmetric structure (n = 13) which has not previously been reported. By calculating the harmonic frequencies of the electrons around their equilibrium positions, we also find the first-order vibrational corrections to the Thomson energy.

  3. Three-dimensional simulation of thermal harmonic lasing free electron laser with detuning of the fundamental

    Energy Technology Data Exchange (ETDEWEB)

    Salehi, E. [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of); Maraghechi, B., E-mail: behrouz@aut.ac.ir [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of); School of Particle and Accelerator Physics, Institute for Research in Fundamental Sciences (IPM), 19395-5531 Tehran (Iran, Islamic Republic of); Mirian, N. S. [School of Particle and Accelerator Physics, Institute for Research in Fundamental Sciences (IPM), 19395-5531 Tehran (Iran, Islamic Republic of); UVSOR Facility (UVSOR), Institute for Molecular Science, Myodaiji, Okazaki 444-8585 (Japan)

    2016-03-15

    Detuning of the fundamental is a way to enhance harmonic generation. By this method, the wiggler is composed of two segments in such a way that the fundamental resonance of the second segment to coincide with the third harmonic of the first segment of the wiggler to generate extreme ultraviolet radiation and x-ray emission. A set of coupled, nonlinear, and first-order differential equations in three dimensions describing the evolution of the electron trajectories and the radiation field with warm beam is solved numerically by CYRUS 3D code in the steady-state for two models (1) seeded free electron laser (FEL) and (2) shot noise on the electron beam (self-amplified spontaneous emission FEL). Thermal effects in the form of longitudinal velocity spread are considered. Three-dimensional simulation describes self-consistently the longitudinal spatial dependence of radiation waists, curvatures, and amplitudes together with the evaluation of the electron beam. The evolutions of the transverse modes are investigated for the fundamental resonance and the third harmonic. Also, the effective modes of the third harmonic are studied. In this paper, we found that detuning of the fundamental with shot noise gives more optimistic result than the seeded FEL.

  4. Intregrating metallic wiring with three-dimensional polystyrene colloidal crystals using electron-beam lithography and three-dimensional laser lithography

    International Nuclear Information System (INIS)

    Tian, Yaolan; Isotalo, Tero J; Konttinen, Mikko P; Li, Jiawei; Heiskanen, Samuli; Geng, Zhuoran; Maasilta, Ilari J

    2017-01-01

    We demonstrate a method to fabricate narrow, down to a few micron wide metallic leads on top of a three-dimensional (3D) colloidal crystal self-assembled from polystyrene (PS) nanospheres of diameter 260 nm, using electron-beam lithography. This fabrication is not straightforward due to the fact that PS nanospheres cannot usually survive the harsh chemical treatments required in the development and lift-off steps of electron-beam lithography. We solve this problem by increasing the chemical resistance of the PS nanospheres using an additional electron-beam irradiation step, which allows the spheres to retain their shape and their self-assembled structure, even after baking to a temperature of 160 °C, the exposure to the resist developer and the exposure to acetone, all of which are required for the electron-beam lithography step. Moreover, we show that by depositing an aluminum oxide capping layer on top of the colloidal crystal after the e-beam irradiation, the surface is smooth enough so that continuous metal wiring can be deposited by the electron-beam lithography. Finally, we also demonstrate a way to self-assemble PS colloidal crystals into a microscale container, which was fabricated using direct-write 3D laser-lithography. Metallic wiring was also successfully integrated with the combination of a container structure and a PS colloidal crystal. Our goal is to make a device for studies of thermal transport in 3D phononic crystals, but other phononic or photonic crystal applications could also be envisioned. (paper)

  5. Electron microscope phase enhancement

    Science.gov (United States)

    Jin, Jian; Glaeser, Robert M.

    2010-06-15

    A microfabricated electron phase shift element is used for modifying the phase characteristics of an electron beam passing though its center aperture, while not affecting the more divergent portion of an incident beam to selectively provide a ninety-degree phase shift to the unscattered beam in the back focal plan of the objective lens, in order to realize Zernike-type, in-focus phase contrast in an electron microscope. One application of the element is to increase the contrast of an electron microscope for viewing weakly scattering samples while in focus. Typical weakly scattering samples include biological samples such as macromolecules, or perhaps cells. Preliminary experimental images demonstrate that these devices do apply a ninety degree phase shift as expected. Electrostatic calculations have been used to determine that fringing fields in the region of the scattered electron beams will cause a negligible phase shift as long as the ratio of electrode length to the transverse feature-size aperture is about 5:1. Calculations are underway to determine the feasibility of aspect smaller aspect ratios of about 3:1 and about 2:1.

  6. Forensic Scanning Electron Microscope

    Science.gov (United States)

    Keeley, R. H.

    1983-03-01

    The scanning electron microscope equipped with an x-ray spectrometer is a versatile instrument which has many uses in the investigation of crime and preparation of scientific evidence for the courts. Major applications include microscopy and analysis of very small fragments of paint, glass and other materials which may link an individual with a scene of crime, identification of firearms residues and examination of questioned documents. Although simultaneous observation and chemical analysis of the sample is the most important feature of the instrument, other modes of operation such as cathodoluminescence spectrometry, backscattered electron imaging and direct x-ray excitation are also exploited. Marks on two bullets or cartridge cases can be compared directly by sequential scanning with a single beam or electronic linkage of two instruments. Particles of primer residue deposited on the skin and clothing when a gun is fired can be collected on adhesive tape and identified by their morphology and elemental composition. It is also possible to differentiate between the primer residues of different types of ammunition. Bullets may be identified from the small fragments left behind as they pass through the body tissues. In the examination of questioned documents the scanning electron microscope is used to establish the order in which two intersecting ink lines were written and to detect traces of chemical markers added to the security inks on official documents.

  7. Clinical application of electron beam computed tomography in intravenous three-dimensional coronary angiography

    International Nuclear Information System (INIS)

    Luo Chufan; Du Zhimin; Hu Chengheng; Li Yi; Zeng Wutao; Ma Hong; Li Xiangmin; Zhou Xuhui

    2002-01-01

    Objective: To investigate the clinical application of intravenous three-dimensional coronary angiography using electron beam computed tomography (EBCT) as compared with selective coronary angiography. Methods: Intravenous EBCT and selective coronary angiography were performed during the same period in 38 patients. The value of EBCT angiography for diagnosing coronary artery disease was evaluated. Results: The number of coronary arteries adequately evaluated by EBCT angiography was 134 out of 152 vessels (88.2%), including 100% of the left main coronary arteries, 94.7% of the left anterior descending arteries, 81.6% of the left circumflex arteries and 76.3 % of the right coronary arteries. Significantly more left main and heft anterior descending coronary arteries were adequately visualized than the left circumflex and right coronary arteries (P < 0.05). The sensitivity, specificity, accuracy, and positive and negative predictive value of EBCT angiography for diagnosing coronary artery disease were 88.0%, 84.6%, 86.8%, 91.7% and 78.6%, respectively. Of the 38 arteries with ≥ 50% stenosis, EBCT underestimated 8, for a sensitivity of 78.9%. Of the 96 arteries without significant stenosis, EBCT overestimated 7 stenosis, for a specificity of 92.7%. Conclusion: Intravenous electron beam computed tomographic coronary angiography is a promising noninvasive method for diagnosing coronary artery disease

  8. Three-dimensional characterization of extreme ultraviolet mask blank defects by interference contrast photoemission electron microscopy.

    Science.gov (United States)

    Lin, Jingquan; Weber, Nils; Escher, Matthias; Maul, Jochen; Han, Hak-Seung; Merkel, Michael; Wurm, Stefan; Schönhense, Gerd; Kleineberg, Ulf

    2008-09-29

    A photoemission electron microscope based on a new contrast mechanism "interference contrast" is applied to characterize extreme ultraviolet lithography mask blank defects. Inspection results show that positioning of interference destructive condition (node of standing wave field) on surface of multilayer in the local region of a phase defect is necessary to obtain best visibility of the defect on mask blank. A comparative experiment reveals superiority of the interference contrast photoemission electron microscope (Extreme UV illumination) over a topographic contrast one (UV illumination with Hg discharge lamp) in detecting extreme ultraviolet mask blank phase defects. A depth-resolved detection of a mask blank defect, either by measuring anti-node peak shift in the EUV-PEEM image under varying inspection wavelength condition or by counting interference fringes with a fixed illumination wavelength, is discussed.

  9. A custom three-dimensional electron bolus technique for optimization of postmastectomy irradiation

    International Nuclear Information System (INIS)

    Perkins, George H.; McNeese, Marsha D.; Antolak, John A.; Buchholz, Thomas A.; Strom, Eric A.; Hogstrom, Kenneth R.

    2001-01-01

    Purpose: Postmastectomy irradiation (PMI) is a technically complex treatment requiring consideration of the primary tumor location, possible risk of internal mammary node involvement, varying chest wall thicknesses secondary to surgical defects or body habitus, and risk of damaging normal underlying structures. In this report, we describe the application of a customized three-dimensional (3D) electron bolus technique for delivering PMI. Methods and Materials: A customized electron bolus was designed using a 3D planning system. Computed tomography (CT) images of each patient were obtained in treatment position and the volume to be treated was identified. The distal surface of the wax bolus matched the skin surface, and the proximal surface was designed to conform to the 90% isodose surface to the distal surface of the planning target volume (PTV). Dose was calculated with a pencil-beam algorithm correcting for patient heterogeneity. The bolus was then fabricated from modeling wax using a computer-controlled milling device. To aid in quality assurance, CT images with the bolus in place were generated and the dose distribution was computed using these images. Results: This technique optimized the dose distribution while minimizing irradiation of normal tissues. The use of a single anterior field eliminated field junction sites. Two patients who benefited from this option are described: one with altered chest wall geometry (congenital pectus excavatum), and one with recurrent disease in the medial chest wall and internal mammary chain (IMC) area. Conclusion: The use of custom 3D electron bolus for PMI is an effective method for optimizing dose delivery. The radiation dose distribution is highly conformal, dose heterogeneity is reduced compared to standard techniques in certain suboptimal settings, and excellent immediate outcome is obtained

  10. Three-dimensional distributions of elements in biological samples by energy-filtered electron tomography

    Energy Technology Data Exchange (ETDEWEB)

    Leapman, R.D.; Kocsis, E.; Zhang, G.; Talbot, T.L.; Laquerriere, P

    2004-07-15

    By combining electron tomography with energy-filtered electron microscopy, we have shown the feasibility of determining the three-dimensional distributions of phosphorus in biological specimens. Thin sections of the nematode, Caenorhabditis elegans were prepared by high-pressure freezing, freeze-substitution and plastic embedding. Images were recorded at energy losses above and below the phosphorus L{sub 2,3} edge using a post-column imaging filter operating at a beam energy of 120 keV. The unstained specimens exhibited minimal contrast in bright-field images. After it was determined that the specimen was sufficiently thin to allow two-window ratio imaging of phosphorus, pairs of pre-edge and post-edge images were acquired in series over a tilt range of {+-}55 deg. at 5 deg. increments for two orthogonal tilt axes. The projected phosphorus distributions were aligned using the pre-edge images that contained inelastic contrast from colloidal gold particles deposited on the specimen surface. A reconstruction and surface rendering of the phosphorus distribution clearly revealed features 15-20 nm in diameter, which were identified as ribosomes distributed along the stacked membranes of endoplasmic reticulum and in the cytoplasm. The sensitivity of the technique was estimated at <35 phosphorus atoms per voxel based on the known total ribosomal phosphorus content of approximately 7000 atoms. Although a high electron dose of approximately 10{sup 7} e/nm{sup 2} was required to record two-axis tilt series, specimens were sufficiently stable to allow image alignment and tomographic reconstruction.

  11. Impact of three-dimensional geometry on the performance of isolated electron-injection infrared detectors

    Energy Technology Data Exchange (ETDEWEB)

    Fathipour, Vala; Jang, Sung Jun; Nia, Iman Hassani; Mohseni, Hooman, E-mail: hmohseni@northwestern.edu [Bio-Inspired Sensors and Optoelectronics Laboratory, Northwestern University, 2145 Sheridan Rd, Evanston, Illinois 60208 (United States)

    2015-01-12

    We present a quantitative study of the influence of three-dimensional geometry of the isolated electron–injection detectors on their characteristics. Significant improvements in the device performance are obtained as a result of scaling the injector diameter with respect to the trapping/absorbing layer diameters. Devices with about ten times smaller injector area with respect to the trapping/absorbing layer areas show more than an order of magnitude lower dark current, as well as an order of magnitude higher optical gain compared with devices of same size injector and trapping/absorbing layer areas. Devices with 10 μm injector diameter and 30 μm trapping/absorbing layer diameter show an optical gain of ∼2000 at bias voltage of −3 V with a cutoff wavelength of 1700 nm. Analytical expressions are derived for the electron-injection detector optical gain to qualitatively explain the significance of scaling the injector with respect to the absorber.

  12. Electronic structures and three-dimensional effects of boron-doped carbon nanotubes

    International Nuclear Information System (INIS)

    Koretsune, Takashi; Saito, Susumu

    2008-01-01

    We study boron-doped carbon nanotubes by first-principles methods based on the density functional theory. To discuss the possibility of superconductivity, we calculate the electronic band structure and the density of states (DOS) of boron-doped (10,0) nanotubes by changing the boron density. It is found that the Fermi level density of states D(ε F ) increases upon lowering the boron density. This can be understood in terms of the rigid band picture where the one-dimensional van Hove singularity lies at the edge of the valence band in the DOS of the pristine nanotube. The effect of three-dimensionality is also considered by performing the calculations for bundled (10,0) nanotubes and boron-doped double-walled carbon nanotubes (10,0)/(19,0). From the calculation of the bundled nanotubes, it is found that interwall dispersion is sufficiently large to broaden the peaks of the van Hove singularity in the DOS. Thus, to achieve the high D(ε F ) using the bundle of nanotubes with single chirality, we should take into account the distance from each nanotube. In the case of double-walled carbon nanotubes, we find that the holes introduced to the inner tube by boron doping spread also on the outer tube, while the band structure of each tube remains almost unchanged.

  13. Spline-based image-to-volume registration for three-dimensional electron microscopy

    International Nuclear Information System (INIS)

    Jonic, S.; Sorzano, C.O.S.; Thevenaz, P.; El-Bez, C.; De Carlo, S.; Unser, M.

    2005-01-01

    This paper presents an algorithm based on a continuous framework for a posteriori angular and translational assignment in three-dimensional electron microscopy (3DEM) of single particles. Our algorithm can be used advantageously to refine the assignment of standard quantized-parameter methods by registering the images to a reference 3D particle model. We achieve the registration by employing a gradient-based iterative minimization of a least-squares measure of dissimilarity between an image and a projection of the volume in the Fourier transform (FT) domain. We compute the FT of the projection using the central-slice theorem (CST). To compute the gradient accurately, we take advantage of a cubic B-spline model of the data in the frequency domain. To improve the robustness of the algorithm, we weight the cost function in the FT domain and apply a 'mixed' strategy for the assignment based on the minimum value of the cost function at registration for several different initializations. We validate our algorithm in a fully controlled simulation environment. We show that the mixed strategy improves the assignment accuracy; on our data, the quality of the angular and translational assignment was better than 2 voxel (i.e., 6.54 A). We also test the performance of our algorithm on real EM data. We conclude that our algorithm outperforms a standard projection-matching refinement in terms of both consistency of 3D reconstructions and speed

  14. Transmission electron microscope CCD camera

    Science.gov (United States)

    Downing, Kenneth H.

    1999-01-01

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

  15. Cryo-electron microscopy and three-dimensional reconstructions of hepatitis C virus particles

    International Nuclear Information System (INIS)

    Yu Xuekui; Qiao Ming; Atanasov, Ivo; Hu Zongyi; Kato, Takanobu; Liang, T. Jake; Zhou, Z. Hong

    2007-01-01

    The structural details of hepatitis C virus (HCV) have been elusive because of the lack of a robust tissue culture system for producing an adequate amount of virions from infectious sources for in-depth three-dimensional (3D) structural analysis. Using both negative-stain and cryo-electron microscopy (cryoEM), we show that HCV virions isolated from cell culture have a rather uniform size of 500 A in diameter and that recombinantly expressed HCV-like particles (HCV-LPs) have similar morphologic, biophysical and antigenic features in spite of the varying sizes of the particles. 3D reconstructions were obtained from HCV-LPs with the same size as the HCV virions in the presence and absence of monoclonal antibodies bound to the E1 glycoprotein. The 3D reconstruction of HCV-LP reveals a multilayered architecture, with smooth outer-layer densities arranged in a 'fishbone' configuration. Reconstruction of the particles in complex with anti-E1 antibodies shows that sites of the E1 epitope are exposed and surround the 5-, 3- and 2-fold axes. The binding pattern of the anti-E1 antibody and the fitting of the structure of the dengue virus E glycoprotein into our 3D reconstructions further suggest that the HCV-LP E1 and E2 proteins form a tetramer (or dimer of heterodimers) that corresponds morphologically and functionally to the flavivirus E homodimer. This first 3D structural analysis of HCV particles offers important insights into the elusive mechanisms of HCV assembly and maturation

  16. Characterization of the bone marrow adipocyte niche with three-dimensional electron microscopy.

    Science.gov (United States)

    Robles, Hero; Park, SungJae; Joens, Matthew S; Fitzpatrick, James A J; Craft, Clarissa S; Scheller, Erica L

    2018-01-27

    Unlike white and brown adipose tissues, the bone marrow adipocyte (BMA) exists in a microenvironment containing unique populations of hematopoietic and skeletal cells. To study this microenvironment at the sub-cellular level, we performed a three-dimensional analysis of the ultrastructure of the BMA niche with focused ion beam scanning electron microscopy (FIB-SEM). This revealed that BMAs display hallmarks of metabolically active cells including polarized lipid deposits, a dense mitochondrial network, and areas of endoplasmic reticulum. The distinct orientations of the triacylglycerol droplets suggest that fatty acids are taken up and/or released in three key areas - at the endothelial interface, into the hematopoietic milieu, and at the bone surface. Near the sinusoidal vasculature, endothelial cells send finger-like projections into the surface of the BMA which terminate near regions of lipid within the BMA cytoplasm. In some regions, perivascular cells encase the BMA with their flattened cellular projections, limiting contacts with other cells in the niche. In the hematopoietic milieu, BMAT adipocytes of the proximal tibia interact extensively with maturing cells of the myeloid/granulocyte lineage. Associations with erythroblast islands are also prominent. At the bone surface, the BMA extends organelle and lipid-rich cytoplasmic regions toward areas of active osteoblasts. This suggests that the BMA may serve to partition nutrient utilization between diverse cellular compartments, serving as an energy-rich hub of the stromal-reticular network. Lastly, though immuno-EM, we've identified a subset of bone marrow adipocytes that are innervated by the sympathetic nervous system, providing an additional mechanism for regulation of the BMA. In summary, this work reveals that the bone marrow adipocyte is a dynamic cell with substantial capacity for interactions with the diverse components of its surrounding microenvironment. These local interactions likely contribute to

  17. Three-dimensional reconstruction of the giant mimivirus particle with an x-ray free-electron laser.

    Science.gov (United States)

    Ekeberg, Tomas; Svenda, Martin; Abergel, Chantal; Maia, Filipe R N C; Seltzer, Virginie; Claverie, Jean-Michel; Hantke, Max; Jönsson, Olof; Nettelblad, Carl; van der Schot, Gijs; Liang, Mengning; DePonte, Daniel P; Barty, Anton; Seibert, M Marvin; Iwan, Bianca; Andersson, Inger; Loh, N Duane; Martin, Andrew V; Chapman, Henry; Bostedt, Christoph; Bozek, John D; Ferguson, Ken R; Krzywinski, Jacek; Epp, Sascha W; Rolles, Daniel; Rudenko, Artem; Hartmann, Robert; Kimmel, Nils; Hajdu, Janos

    2015-03-06

    We present a proof-of-concept three-dimensional reconstruction of the giant mimivirus particle from experimentally measured diffraction patterns from an x-ray free-electron laser. Three-dimensional imaging requires the assembly of many two-dimensional patterns into an internally consistent Fourier volume. Since each particle is randomly oriented when exposed to the x-ray pulse, relative orientations have to be retrieved from the diffraction data alone. We achieve this with a modified version of the expand, maximize and compress algorithm and validate our result using new methods.

  18. Optical studies of three dimensional confinement in photonic and electronic systems

    International Nuclear Information System (INIS)

    Adawi, Ali Mohammad Ahmad

    2002-01-01

    fluorescence spectra reveal a stop band region with a centre varying with angle according to Bragg's law. It is found that the fluorescence stop band is much shallower and narrower than that observed in transmission spectra. The gap narrowing in the fluorescence spectra is attributed to the scattering events inside the opal taking into account the spectral dependence of the Bragg attenuation length. High refractive index contrast opal photonic crystals are achieved by infiltration with chalcogenide glasses (As 2 S 3 and AsSe) by precipitation from solution. Optical imaging of the samples after infiltration shows that chalcogenide glasses tend to aggregate into submillimeter areas inside opals. Spatially resolved reflectivity spectroscopy is used to characterise the infiltrated areas. Large shift (up to 80 nm) in the position of the stop band has been achieved from the infiltrated samples in comparison to the samples before infiltration. In the second part of this thesis, mid-infrared (2.5 μm-15 μm) intersubband transitions in the conduction band of uncoupled and vertically coupled and also in the valence band of self assembled ln(Ga)As/GaAs quantum dots are investigated using direct absorption measurements and photocurrent spectroscopy. The investigated dots show three dimensional electronic confinement. Intersubband transitions are investigated as a function of the polarisation angle of the incident radiation, external electric field and temperature. The experimental results indicate that intersubband transitions in the conduction band of the uncoupled dots are allowed for radiation polarised in the growth direction, similar to that found for quantum wells. By strongly coupling quantum dots in the growth direction (10 A GaAs barrier between the dots) we have achieved a reversal of the intersubband selection rule for optical transitions between conduction band states, compared with that observed for uncoupled dots. We find that for strongly coupled dots the dominant

  19. Two- to three-dimensional crossover in a dense electron liquid in silicon

    Science.gov (United States)

    Matmon, Guy; Ginossar, Eran; Villis, Byron J.; Kölker, Alex; Lim, Tingbin; Solanki, Hari; Schofield, Steven R.; Curson, Neil J.; Li, Juerong; Murdin, Ben N.; Fisher, Andrew J.; Aeppli, Gabriel

    2018-04-01

    Doping of silicon via phosphine exposures alternating with molecular beam epitaxy overgrowth is a path to Si:P substrates for conventional microelectronics and quantum information technologies. The technique also provides a well-controlled material for systematic studies of two-dimensional lattices with a half-filled band. We show here that for a dense (ns=2.8 ×1014 cm-2) disordered two-dimensional array of P atoms, the full field magnitude and angle-dependent magnetotransport is remarkably well described by classic weak localization theory with no corrections due to interaction. The two- to three-dimensional crossover seen upon warming can also be interpreted using scaling concepts developed for anistropic three-dimensional materials, which work remarkably except when the applied fields are nearly parallel to the conducting planes.

  20. Design and performance of a high-resolution frictional force microscope with quantitative three-dimensional force sensitivity

    International Nuclear Information System (INIS)

    Dienwiebel, M.; Kuyper, E. de; Crama, L.; Frenken, J.W.M.; Heimberg, J.A.; Spaanderman, D.-J.; Glatra van Loon, D.; Zijlstra, T.; Drift, E. van der

    2005-01-01

    In this article, the construction and initial tests of a frictional force microscope are described. The instrument makes use of a microfabricated cantilever that allows one to independently measure the lateral forces in X and Y directions as well as the normal force. We use four fiber-optic interferometers to detect the motion of the sensor in three dimensions. The properties of our cantilevers allow easy and accurate normal and lateral force calibration, making it possible to measure the lateral force on a fully quantitative basis. First experiments on highly oriented pyrolytic graphite demonstrate that the microscope is capable of measuring lateral forces with a resolution down to 15 pN

  1. Two- and three dimensional electrons and photons and their supersymmetric partners

    International Nuclear Information System (INIS)

    Steringa, J.J.

    1989-01-01

    This thesis contains a study of supersymmetric gauge theories in two and tree spacetime dimensions. Supersymmetric gauge theories in less than four spacetime dimensions are useful for trying out field theoretical methods which ultimately will be applied to realistic models. In ch. 1 all the aspects of field theory that are necessary for later chapters are treated. In ch. 2 sypersymmetry in two- and three-dimensional space time is treated, and superfields and superspace techniques are introduced. With these a simple Abelian supersymmetric gauge theory in two spacetime dimensions is constructed, the Schwinger model. Ch. 3 deals with general properties and a perturbative analysis of the model. Ch. 4 contains a non-perturbative analysis by means of Dyson-Schwinger equations. A supersummetric extension of theSalam-Delbourgo Gauge Technique is presented and is applied with some seccess to the supersymmetric Schwinger model. In ch. 5 prperties of three-dimensional supersymmetric gauge theories are investigated. (author). 55 refs.; 7 figs.; schemes

  2. A fluorescence scanning electron microscope

    International Nuclear Information System (INIS)

    Kanemaru, Takaaki; Hirata, Kazuho; Takasu, Shin-ichi; Isobe, Shin-ichiro; Mizuki, Keiji; Mataka, Shuntaro; Nakamura, Kei-ichiro

    2009-01-01

    Fluorescence techniques are widely used in biological research to examine molecular localization, while electron microscopy can provide unique ultrastructural information. To date, correlative images from both fluorescence and electron microscopy have been obtained separately using two different instruments, i.e. a fluorescence microscope (FM) and an electron microscope (EM). In the current study, a scanning electron microscope (SEM) (JEOL JXA8600 M) was combined with a fluorescence digital camera microscope unit and this hybrid instrument was named a fluorescence SEM (FL-SEM). In the labeling of FL-SEM samples, both Fluolid, which is an organic EL dye, and Alexa Fluor, were employed. We successfully demonstrated that the FL-SEM is a simple and practical tool for correlative fluorescence and electron microscopy.

  3. Resolving three-dimensional shape of sub-50 nm wide lines with nanometer-scale sensitivity using conventional optical microscopes

    International Nuclear Information System (INIS)

    Attota, Ravikiran; Dixson, Ronald G.

    2014-01-01

    We experimentally demonstrate that the three-dimensional (3-D) shape variations of nanometer-scale objects can be resolved and measured with sub-nanometer scale sensitivity using conventional optical microscopes by analyzing 4-D optical data using the through-focus scanning optical microscopy (TSOM) method. These initial results show that TSOM-determined cross-sectional (3-D) shape differences of 30 nm–40 nm wide lines agree well with critical-dimension atomic force microscope measurements. The TSOM method showed a linewidth uncertainty of 1.22 nm (k = 2). Complex optical simulations are not needed for analysis using the TSOM method, making the process simple, economical, fast, and ideally suited for high volume nanomanufacturing process monitoring.

  4. A Medipix quantum area detector allows rotation electron diffraction data collection from submicrometre three-dimensional protein crystals

    Energy Technology Data Exchange (ETDEWEB)

    Nederlof, Igor; Genderen, Eric van; Li, Yao-Wang; Abrahams, Jan Pieter, E-mail: abrahams@chem.leidenuniv.nl [Leiden University, Einsteinweg 55, 2333 CC Leiden (Netherlands)

    2013-07-01

    An ultrasensitive Medipix2 detector allowed the collection of rotation electron-diffraction data from single three-dimensional protein nanocrystals for the first time. The data could be analysed using the standard X-ray crystallography programs MOSFLM and SCALA. When protein crystals are submicrometre-sized, X-ray radiation damage precludes conventional diffraction data collection. For crystals that are of the order of 100 nm in size, at best only single-shot diffraction patterns can be collected and rotation data collection has not been possible, irrespective of the diffraction technique used. Here, it is shown that at a very low electron dose (at most 0.1 e{sup −} Å{sup −2}), a Medipix2 quantum area detector is sufficiently sensitive to allow the collection of a 30-frame rotation series of 200 keV electron-diffraction data from a single ∼100 nm thick protein crystal. A highly parallel 200 keV electron beam (λ = 0.025 Å) allowed observation of the curvature of the Ewald sphere at low resolution, indicating a combined mosaic spread/beam divergence of at most 0.4°. This result shows that volumes of crystal with low mosaicity can be pinpointed in electron diffraction. It is also shown that strategies and data-analysis software (MOSFLM and SCALA) from X-ray protein crystallography can be used in principle for analysing electron-diffraction data from three-dimensional nanocrystals of proteins.

  5. A Medipix quantum area detector allows rotation electron diffraction data collection from submicrometre three-dimensional protein crystals

    International Nuclear Information System (INIS)

    Nederlof, Igor; Genderen, Eric van; Li, Yao-Wang; Abrahams, Jan Pieter

    2013-01-01

    An ultrasensitive Medipix2 detector allowed the collection of rotation electron-diffraction data from single three-dimensional protein nanocrystals for the first time. The data could be analysed using the standard X-ray crystallography programs MOSFLM and SCALA. When protein crystals are submicrometre-sized, X-ray radiation damage precludes conventional diffraction data collection. For crystals that are of the order of 100 nm in size, at best only single-shot diffraction patterns can be collected and rotation data collection has not been possible, irrespective of the diffraction technique used. Here, it is shown that at a very low electron dose (at most 0.1 e − Å −2 ), a Medipix2 quantum area detector is sufficiently sensitive to allow the collection of a 30-frame rotation series of 200 keV electron-diffraction data from a single ∼100 nm thick protein crystal. A highly parallel 200 keV electron beam (λ = 0.025 Å) allowed observation of the curvature of the Ewald sphere at low resolution, indicating a combined mosaic spread/beam divergence of at most 0.4°. This result shows that volumes of crystal with low mosaicity can be pinpointed in electron diffraction. It is also shown that strategies and data-analysis software (MOSFLM and SCALA) from X-ray protein crystallography can be used in principle for analysing electron-diffraction data from three-dimensional nanocrystals of proteins

  6. Three-dimensional ultrastructure of osteocytes assessed by focused ion beam-scanning electron microscopy (FIB-SEM).

    Science.gov (United States)

    Hasegawa, Tomoka; Yamamoto, Tomomaya; Hongo, Hiromi; Qiu, Zixuan; Abe, Miki; Kanesaki, Takuma; Tanaka, Kawori; Endo, Takashi; de Freitas, Paulo Henrique Luiz; Li, Minqi; Amizuka, Norio

    2018-04-01

    The aim of this study is to demonstrate the application of focused ion beam-scanning electron microscopy, FIB-SEM for revealing the three-dimensional features of osteocytic cytoplasmic processes in metaphyseal (immature) and diaphyseal (mature) trabeculae. Tibiae of eight-week-old male mice were fixed with aldehyde solution, and treated with block staining prior to FIB-SEM observation. While two-dimensional backscattered SEM images showed osteocytes' cytoplasmic processes in a fragmented fashion, three-dimensional reconstructions of FIB-SEM images demonstrated that osteocytes in primary metaphyseal trabeculae extended their cytoplasmic processes randomly, thus maintaining contact with neighboring osteocytes and osteoblasts. In contrast, diaphyseal osteocytes extended thin cytoplasmic processes from their cell bodies, which ran perpendicular to the bone surface. In addition, these osteocytes featured thick processes that branched into thinner, transverse cytoplasmic processes; at some point, however, these transverse processes bend at a right angle to run perpendicular to the bone surface. Osteoblasts also possessed thicker cytoplasmic processes that branched off as thinner processes, which then connected with cytoplasmic processes of neighboring osteocytes. Thus, FIB-SEM is a useful technology for visualizing the three-dimensional structures of osteocytes and their cytoplasmic processes.

  7. Three-dimensional structure determination protocol for noncrystalline biomolecules using x-ray free-electron laser diffraction imaging.

    Science.gov (United States)

    Oroguchi, Tomotaka; Nakasako, Masayoshi

    2013-02-01

    Coherent and intense x-ray pulses generated by x-ray free-electron laser (XFEL) sources are paving the way for structural determination of noncrystalline biomolecules. However, due to the small scattering cross section of electrons for x rays, the available incident x-ray intensity of XFEL sources, which is currently in the range of 10(12)-10(13) photons/μm(2)/pulse, is lower than that necessary to perform single-molecule diffraction experiments for noncrystalline biomolecules even with the molecular masses of megadalton and submicrometer dimensions. Here, we propose an experimental protocol and analysis method for visualizing the structure of those biomolecules by the combined application of coherent x-ray diffraction imaging and three-dimensional reconstruction methods. To compensate the small scattering cross section of biomolecules, in our protocol, a thin vitreous ice plate containing several hundred biomolecules/μm(2) is used as sample, a setup similar to that utilized by single-molecule cryoelectron microscopy. The scattering cross section of such an ice plate is far larger than that of a single particle. The images of biomolecules contained within irradiated areas are then retrieved from each diffraction pattern, and finally provide the three-dimensional electron density model. A realistic atomic simulation using large-scale computations proposed that the three-dimensional structure determination of the 50S ribosomal subunit embedded in a vitreous ice plate is possible at a resolution of 0.8 nm when an x-ray beam of 10(16) photons/500×500 nm(2)/pulse is available.

  8. Analysis of the three-dimensional delamination behavior of stretchable electronics applications

    NARCIS (Netherlands)

    Sluis, van der O.; Timmermans, P.H.M.; Zanden, van der E.J.L.; Hoefnagels, J.P.M.; Ernst, L.J.

    2009-01-01

    Stretchable electronics offer potential application areasin biological implants interacting with human tissue. Furthermore, they facilitate increased design freedom of electronic products. Typical applications can be found in healthcare, wellness and functional clothes. A key requirement on these

  9. Controlling a three dimensional electron slab of graded Al{sub x}Ga{sub 1−x}N

    Energy Technology Data Exchange (ETDEWEB)

    Adhikari, R., E-mail: rajdeep.adhikari@jku.at; Capuzzo, G.; Bonanni, A., E-mail: alberta.bonanni@jku.at [Institut für Halbleiter-und-Festkörperphysik, Johannes Kepler University, Altenbergerstr. 69, A-4040 Linz (Austria); Li, Tian [Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, PL-02 668 Warszawa (Poland)

    2016-01-11

    Polarization induced degenerate n-type doping with electron concentrations up to ∼10{sup 20 }cm{sup −3} is achieved in graded Al{sub x}Ga{sub 1−x}N layers (x: 0% → 37%) grown on unintentionally doped and on n-doped GaN:Si buffer/reservoir layers by metal organic vapor phase epitaxy. High resolution x-ray diffraction, transmission electron microscopy, and electron dispersive x-ray spectroscopy confirm the gradient in the composition of the Al{sub x}Ga{sub 1−x}N layers, while Hall effect studies reveal the formation of a three dimensional electron slab, whose conductivity can be adjusted through the GaN(:Si) buffer/reservoir.

  10. Electron microscope studies

    International Nuclear Information System (INIS)

    Crewe, A.V.; Kapp, O.H.

    1990-01-01

    Our laboratory has made significant progress this year in devising improved electron-optical systems, in studying invertebrate hemoglobins with the STEM, and in achieving a workable sub-angstrom STEM. Our goal in electron optics is to improve resolution by producing spherical and chromatic aberration coefficients with signs opposite those of magnetic lenses. We have progressed toward this goal through calculations that explore the addition of electrodes to electron mirrors to reduce these two geometric aberrations and by devising a beam separation system that won't introduce asymmetrical aberrations. Some promising new designs of magnetic lenses for SEM applications have also been investigated. We have continued our exploration of the quaternary structure of the invertebrate hemoglobins and are now among the top laboratories in this area of expertise. In addition, we have overcome many of our electronic difficulties on the sub-angstrom STEM and have made significant progress toward achieving an operational system. The addition of an IBM RISC-6000 workstation to our lab has significantly increased our image processing capabilities

  11. Microscopic entropy of the three-dimensional rotating black hole of Bergshoeff-Hohm-Townsend massive gravity

    International Nuclear Information System (INIS)

    Giribet, Gaston; Oliva, Julio; Tempo, David; Troncoso, Ricardo

    2009-01-01

    Asymptotically anti-de Sitter rotating black holes for the Bergshoeff-Hohm-Townsend massive gravity theory in three dimensions are considered. In the special case when the theory admits a unique maximally symmetric solution, apart from the mass and the angular momentum, the black hole is described by an independent 'gravitational hair' parameter, which provides a negative lower bound for the mass. This bound is saturated at the extremal case, and since the temperature and the semiclassical entropy vanish, it is naturally regarded as the ground state. The absence of a global charge associated with the gravitational hair parameter reflects itself through the first law of thermodynamics in the fact that the variation of this parameter can be consistently reabsorbed by a shift of the global charges, giving further support to consider the extremal case as the ground state. The rotating black hole fits within relaxed asymptotic conditions as compared with the ones of Brown and Henneaux, such that they are invariant under the standard asymptotic symmetries spanned by two copies of the Virasoro generators, and the algebra of the conserved charges acquires a central extension. Then it is shown that Strominger's holographic computation for general relativity can also be extended to the Bergshoeff-Hohm-Townsend theory; i.e., assuming that the quantum theory could be consistently described by a dual conformal field theory at the boundary, the black hole entropy can be microscopically computed from the asymptotic growth of the number of states according to Cardy's formula, in exact agreement with the semiclassical result.

  12. The trajectories of secondary electrons in the scanning electron microscope.

    Science.gov (United States)

    Konvalina, Ivo; Müllerová, Ilona

    2006-01-01

    Three-dimensional simulations of the trajectories of secondary electrons (SE) in the scanning electron microscope have been performed for plenty of real configurations of the specimen chamber, including all its basic components. The primary purpose was to evaluate the collection efficiency of the Everhart-Thornley detector of SE and to reveal fundamental rules for tailoring the set-ups in which efficient signal acquisition can be expected. Intuitive realizations about the easiness of attracting the SEs towards the biased front grid of the detector have shown themselves likely as false, and all grounded objects in the chamber have been proven to influence the spatial distribution of the signal-extracting field. The role of the magnetic field penetrating from inside the objective lens is shown to play an ambiguous role regarding possible support for the signal collection.

  13. Two- and three-dimensional magnetoinductive particle codes with guiding center electron motion

    International Nuclear Information System (INIS)

    Geary, J.L.; Tajima, T.; Leboeuf, J.N.; Zaidman, E.G.; Han, J.H.

    1986-07-01

    A magnetoinductive (Darwin) particle simulation model developed for examining low frequency plasma behavior with large time steps is presented. Electron motion perpendicular to the magnetic field is treated as massless keeping only the guiding center motion. Electron motion parallel to the magnetic field retains full inertial effects as does the ion motion. This model has been implemented in two and three dimensions. Computational tests of the equilibrium properties of the code are compared with linear theory and the fluctuation dissipation theorem. This code has been applied to the problems of Alfven wave resonance heating and twist-kink modes

  14. Electron microscope studies

    International Nuclear Information System (INIS)

    Crewe, A.V.; Kapp, O.H.

    1991-01-01

    This year our laboratory has continued to make progress in the design of electron-optical systems, in the study of structure-function relationships of large multi-subunit proteins, in the development of new image processing software and in achieving a workable sub-angstrom STEM. We present an algebraic approach to the symmetrical Einzel (unipotential) lens wherein we simplify the analysis by specifying a field shape that meets some preferred set of boundary or other conditions and then calculate the fields. In a second study we generalize this approach to study of three element electrostatic lenses of which the symmetrical Einzel lens is a particular form. The purpose is to develop a method for assisting in the design of a lens for a particular purpose. In our biological work we study a stable and functional dodecameric complex of globin chains from the hemoglobin of Lumbricus terrestris. This is a complex lacking the ''linker'' subunit first imaged in this lab and required for maintenance of the native structure. In addition, we do a complete work-up on the hemoglobin of the marine polychaete Eudistylia vancouverii demonstrating the presence of a hierarchy of globin complexes. We demonstrate stable field-emission in the sub-angstrom STEM and the preliminary alignment of the beam. We continue our exploration of a algorithms for alignment of sequences of protein and DNA. Our computer facilities now include four second generation RISC workstations and we continue to take increasing advantage of the floating-point and graphical performance of these devices

  15. Flexible non-diffractive vortex microscope for three-dimensional depth-enhanced super-localization of dielectric, metal and fluorescent nanoparticles

    Science.gov (United States)

    Bouchal, Petr; Bouchal, Zdeněk

    2017-10-01

    In the past decade, probe-based super-resolution using temporally resolved localization of emitters became a groundbreaking imaging strategy in fluorescence microscopy. Here we demonstrate a non-diffractive vortex microscope (NVM), enabling three-dimensional super-resolution fluorescence imaging and localization and tracking of metal and dielectric nanoparticles. The NVM benefits from vortex non-diffractive beams (NBs) creating a double-helix point spread function that rotates under defocusing while maintaining its size and shape unchanged. Using intrinsic properties of the NBs, the dark-field localization of weakly scattering objects is achieved in a large axial range exceeding the depth of field of the microscope objective up to 23 times. The NVM was developed using an upright microscope Nikon Eclipse E600 operating with a spiral lithographic mask optimized using Fisher information and built into an add-on imaging module or microscope objective. In evaluation of the axial localization accuracy the root mean square error below 18 nm and 280 nm was verified over depth ranges of 3.5 μm and 13.6 μm, respectively. Subwavelength gold and polystyrene beads were localized with isotropic precision below 10 nm in the axial range of 3.5 μm and the axial precision reduced to 30 nm in the extended range of 13.6 μm. In the fluorescence imaging, the localization with isotropic precision below 15 nm was demonstrated in the range of 2.5 μm, whereas in the range of 8.3 μm, the precision of 15 nm laterally and 30-50 nm axially was achieved. The tracking of nanoparticles undergoing Brownian motion was demonstrated in the volume of 14 × 10 × 16 μm3. Applicability of the NVM was tested by fluorescence imaging of LW13K2 cells and localization of cellular proteins.

  16. Ion beam neutralization using three-dimensional electron confinement by surface modification of magnetic poles

    Energy Technology Data Exchange (ETDEWEB)

    Nicolaescu, Dan, E-mail: Dan.Nicolaescu@kt2.ecs.kyoto-u.ac.jp [Department of Electronic Science and Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Sakai, Shigeki [Nissin Ion Equipment Co., Ltd., 575 Kuze Tonoshiro-cho, Minami-ku, Kyoto 601-8205 (Japan); Gotoh, Yasuhito [Department of Electronic Science and Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Ishikawa, Junzo [Department of Electronics and Information Engineering, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501 (Japan)

    2011-07-21

    Advanced implantation systems used for semiconductor processing require transportation of quasi-parallel ion beams, which have low energy ({sup 11}B{sup +}, {sup 31}P{sup +},{sup 75}As{sup +}, E{sub ion}=200-1000 eV). Divergence of the ion beam due to space charge effects can be compensated through injection of electrons into different regions of the ion beam. The present study shows that electron confinement takes place in regions of strong magnetic field such as collimator magnet provided with surface mirror magnetic fields and that divergence of the ion beam passing through such regions is largely reduced. Modeling results have been obtained using Opera3D/Tosca/Scala. Electrons may be provided by collision between ions and residual gas molecules or may be injected by field emitter arrays. The size of surface magnets is chosen such as not to disturb ion beam collimation, making the approach compatible with ion beam systems. Surface magnets may form thin magnetic layers with thickness h=0.5 mm or less. Conditions for spacing of surface magnet arrays for optimal electron confinement are outlined.

  17. Electron correlation in a three dimensional cluster of the cubic lattice ...

    African Journals Online (AJOL)

    ... and pairing correlations depend implicitly on the interaction strength (U/41). It is shown that for two electrons, the interaction is always repulsive in the ground state for any positive value of the on-site Coulomb interaction U. Implications of this result for superconductivity are also discussed. Nigerian Journal of Physics Vol.

  18. Three-dimensional neutron dose distribution in the environment around a 1-GeV electron synchrotron facility at INS

    International Nuclear Information System (INIS)

    Uwamino, Y.; Nakamura, T.

    1987-01-01

    The three-dimensional (surface and altitude) skyshine neutron-dose-equivalent distribution around the 1-GeV electron synchrotron (ES) of the Institute for Nuclear Study, University of Tokyo, was measured with a high-sensitivity dose-equivalent counter. The neutron spectrum in the environment was also measured with a multimoderator spectrometer incorporating a 3 He counter. The dose-equivalent distribution and the leakage neutron spectrum at the surface of the ES building were measured with a Studsvik 2202D counter and the multimoderator spectrometer, including an indium activation detector. Skyshine neutron transport calculations, beginning with the photoneutron spectrum and yielding the dose-equivalent distribution in the environment, were performed with the DOT3.5 code and two Monte Carlo codes, MMCR-2 and MMCR-3, using the DLC-87/HILO group cross sections. The calculated neutron spectra at the top surface of the concrete ceiling and at a point 111 m from the ES agreed well with the measured results, and the calculated three-dimensional dose-equivalent distribution also agreed. The dose value increased linearly with altitude, and the slope was estimated for neutron-producing facilities. (author)

  19. Linear and nonlinear studies of velocity shear driven three dimensional electron-magnetohydrodynamics instability

    International Nuclear Information System (INIS)

    Gaur, Gurudatt; Das, Amita

    2012-01-01

    The study of electron velocity shear driven instability in electron magnetohydrodynamics (EMHD) regime in three dimensions has been carried out. It is well known that the instability is non-local in the plane defined by the flow direction and that of the shear, which is the usual Kelvin-Helmholtz mode, often termed as the sausage mode in the context of EMHD. On the other hand, a local instability with perturbations in the plane defined by the shear and the magnetic field direction exists which is termed as kink mode. The interplay of these two modes for simple sheared flow case as well as that when an external magnetic field exists has been studied extensively in the present manuscript in both linear and nonlinear regimes. Finally, these instability processes have been investigated for the exact 2D dipole solutions of EMHD equations [M. B. Isichenko and A. N. Marnachev, Sov. Phys. JETP 66, 702 (1987)] for which the electron flow velocity is sheared. It has been shown that dipoles are very robust and stable against the sausage mode as the unstable wavelengths are typically longer than the dipole size. However, we observe that they do get destabilized by the local kink mode.

  20. Three-dimensional electron diffraction as a complementary technique to powder X-ray diffraction for phase identification and structure solution of powders.

    Science.gov (United States)

    Yun, Yifeng; Zou, Xiaodong; Hovmöller, Sven; Wan, Wei

    2015-03-01

    Phase identification and structure determination are important and widely used techniques in chemistry, physics and materials science. Recently, two methods for automated three-dimensional electron diffraction (ED) data collection, namely automated diffraction tomography (ADT) and rotation electron diffraction (RED), have been developed. Compared with X-ray diffraction (XRD) and two-dimensional zonal ED, three-dimensional ED methods have many advantages in identifying phases and determining unknown structures. Almost complete three-dimensional ED data can be collected using the ADT and RED methods. Since each ED pattern is usually measured off the zone axes by three-dimensional ED methods, dynamic effects are much reduced compared with zonal ED patterns. Data collection is easy and fast, and can start at any arbitrary orientation of the crystal, which facilitates automation. Three-dimensional ED is a powerful technique for structure identification and structure solution from individual nano- or micron-sized particles, while powder X-ray diffraction (PXRD) provides information from all phases present in a sample. ED suffers from dynamic scattering, while PXRD data are kinematic. Three-dimensional ED methods and PXRD are complementary and their combinations are promising for studying multiphase samples and complicated crystal structures. Here, two three-dimensional ED methods, ADT and RED, are described. Examples are given of combinations of three-dimensional ED methods and PXRD for phase identification and structure determination over a large number of different materials, from Ni-Se-O-Cl crystals, zeolites, germanates, metal-organic frameworks and organic compounds to intermetallics with modulated structures. It is shown that three-dimensional ED is now as feasible as X-ray diffraction for phase identification and structure solution, but still needs further development in order to be as accurate as X-ray diffraction. It is expected that three-dimensional ED methods

  1. Three-dimensional electron diffraction as a complementary technique to powder X-ray diffraction for phase identification and structure solution of powders

    Directory of Open Access Journals (Sweden)

    Yifeng Yun

    2015-03-01

    Full Text Available Phase identification and structure determination are important and widely used techniques in chemistry, physics and materials science. Recently, two methods for automated three-dimensional electron diffraction (ED data collection, namely automated diffraction tomography (ADT and rotation electron diffraction (RED, have been developed. Compared with X-ray diffraction (XRD and two-dimensional zonal ED, three-dimensional ED methods have many advantages in identifying phases and determining unknown structures. Almost complete three-dimensional ED data can be collected using the ADT and RED methods. Since each ED pattern is usually measured off the zone axes by three-dimensional ED methods, dynamic effects are much reduced compared with zonal ED patterns. Data collection is easy and fast, and can start at any arbitrary orientation of the crystal, which facilitates automation. Three-dimensional ED is a powerful technique for structure identification and structure solution from individual nano- or micron-sized particles, while powder X-ray diffraction (PXRD provides information from all phases present in a sample. ED suffers from dynamic scattering, while PXRD data are kinematic. Three-dimensional ED methods and PXRD are complementary and their combinations are promising for studying multiphase samples and complicated crystal structures. Here, two three-dimensional ED methods, ADT and RED, are described. Examples are given of combinations of three-dimensional ED methods and PXRD for phase identification and structure determination over a large number of different materials, from Ni–Se–O–Cl crystals, zeolites, germanates, metal–organic frameworks and organic compounds to intermetallics with modulated structures. It is shown that three-dimensional ED is now as feasible as X-ray diffraction for phase identification and structure solution, but still needs further development in order to be as accurate as X-ray diffraction. It is expected that three-dimensional

  2. THREE-DIMENSIONAL OBSERVATIONS ON THICK BIOLOGICAL SPECIMENS BY HIGH VOLTAGE ELECTRON MICROSCOPY

    Directory of Open Access Journals (Sweden)

    Tetsuji Nagata

    2011-05-01

    Full Text Available Thick biological specimens prepared as whole mount cultured cells or thick sections from embedded tissues were stained with histochemical reactions, such as thiamine pyrophosphatase, glucose-6-phosphatase, cytochrome oxidase, acid phosphatase, DAB reactions and radioautography, to observe 3-D ultrastructures of cell organelles producing stereo-pairs by high voltage electron microscopy at accerelating voltages of 400-1000 kV. The organelles demonstrated were Golgi apparatus, endoplasmic reticulum, mitochondria, lysosomes, peroxisomes, pinocytotic vesicles and incorporations of radioactive compounds. As the results, those cell organelles were observed 3- dimensionally and the relative relationships between these organelles were demonstrated.

  3. Carbon nanotube based 3-D matrix for enabling three-dimensional nano-magneto-electronics [corrected].

    Directory of Open Access Journals (Sweden)

    Jeongmin Hong

    Full Text Available This letter describes the use of vertically aligned carbon nanotubes (CNT-based arrays with estimated 2-nm thick cobalt (Co nanoparticles deposited inside individual tubes to unravel the possibility of using the unique templates for ultra-high-density low-energy 3-D nano-magneto-electronic devices. The presence of oriented 2-nm thick Co layers within individual nanotubes in the CNT-based 3-D matrix is confirmed through VSM measurements as well as an energy-dispersive X-ray spectroscopy (EDS.

  4. Three dimensional electrostatic solitary waves in a dense magnetoplasma with relativistically degenerate electrons

    Energy Technology Data Exchange (ETDEWEB)

    Ata-ur-Rahman,; Qamar, A. [Institute of Physics and Electronics, University of Peshawar, Peshawar 25000 (Pakistan); National Centre for Physics, QAU Campus, Shahdrah Valley Road, Islamabad 44000 (Pakistan); Masood, W. [National Centre for Physics, QAU Campus, Shahdrah Valley Road, Islamabad 44000 (Pakistan); COMSATS, Institute of Information Technology, Park Road, Chak Shahzad, Islamabad 44000 (Pakistan); Eliasson, B. [Physics Department, University of Strathclyde, Glasgow G4 0NG, Scotland (United Kingdom)

    2013-09-15

    In this paper, small but finite amplitude electrostatic solitary waves in a relativistic degenerate magnetoplasma, consisting of relativistically degenerate electrons and non-degenerate cold ions, are investigated. The Zakharov-Kuznetsov equation is derived employing the reductive perturbation technique and its solitary wave solution is analyzed. It is shown that only compressive electrostatic solitary structures can propagate in such a degenerate plasma system. The effects of plasma number density, ion cyclotron frequency, and direction cosines on the profiles of ion acoustic solitary waves are investigated and discussed at length. The relevance of the present investigation vis-a-vis pulsating white dwarfs is also pointed out.

  5. Three dimensional mapping of Fe dopants in ceria nanocrystals using direct spectroscopic electron tomography

    Energy Technology Data Exchange (ETDEWEB)

    Goris, Bart; Meledina, Maria; Turner, Stuart [EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Zhong, Zhichao [Centrum Wiskunde & Informatica, P.O. Box 94079, 1090 GB Amsterdam (Netherlands); Batenburg, K. Joost [Centrum Wiskunde & Informatica, P.O. Box 94079, 1090 GB Amsterdam (Netherlands); Mathematical Institute, Leiden University, Niels Bohrweg 1, 2333CA Leiden (Netherlands); Bals, Sara [EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium)

    2016-12-15

    Electron tomography is a powerful technique for the 3D characterization of the morphology of nanostructures. Nevertheless, resolving the chemical composition of complex nanostructures in 3D remains challenging and the number of studies in which electron energy loss spectroscopy (EELS) is combined with tomography is limited. During the last decade, dedicated reconstruction algorithms have been developed for HAADF-STEM tomography using prior knowledge about the investigated sample. Here, we will use the prior knowledge that the experimental spectrum of each reconstructed voxel is a linear combination of a well-known set of references spectra in a so-called direct spectroscopic tomography technique. Based on a simulation experiment, it is shown that this technique provides superior results in comparison to conventional reconstruction methods for spectroscopic data, especially for spectrum images containing a relatively low signal to noise ratio. Next, this technique is used to investigate the spatial distribution of Fe dopants in Fe:Ceria nanoparticles in 3D. It is shown that the presence of the Fe{sup 2+} dopants is correlated with a reduction of the Ce atoms from Ce{sup 4+} towards Ce{sup 3+}. In addition, it is demonstrated that most of the Fe dopants are located near the voids inside the nanoparticle. - Highlights: • A direct tomographic reconstruction technique is proposed for spectroscopic data. • Spectrum fitting is combined with a tomography reconstruction in a single step. • The technique yields superior results for data with a low signal to noise ratio. • The technique is applied to map Fe dopants in ceria nanoparticles.

  6. Three-Dimensional Printed Poly(vinyl alcohol) Substrate with Controlled On-Demand Degradation for Transient Electronics.

    Science.gov (United States)

    Yoon, Jinsu; Han, Jungmin; Choi, Bongsik; Lee, Yongwoo; Kim, Yeamin; Park, Jinhee; Lim, Meehyun; Kang, Min-Ho; Kim, Dae Hwan; Kim, Dong Myong; Kim, Sungho; Choi, Sung-Jin

    2018-05-25

    Electronics that degrade after stable operation for a desired operating time, called transient electronics, are of great interest in many fields, including biomedical implants, secure memory devices, and environmental sensors. Thus, the development of transient materials is critical for the advancement of transient electronics and their applications. However, previous reports have mostly relied on achieving transience in aqueous solutions, where the transience time is largely predetermined based on the materials initially selected at the beginning of the fabrication. Therefore, accurate control of the transience time is difficult, thereby limiting their application. In this work, we demonstrate transient electronics based on a water-soluble poly(vinyl alcohol) (PVA) substrate on which carbon nanotube (CNT)-based field-effect transistors were fabricated. We regulated the structural parameters of the PVA substrate using a three-dimensional (3D) printer to accurately control and program the transience time of the PVA substrate in water. The 3D printing technology can produce complex objects directly, thus enabling the efficient fabrication of a transient substrate with a prescribed and controlled transience time. In addition, the 3D printer was used to develop a facile method for the selective and partial destruction of electronics.

  7. Three-dimensional reconstruction of axonemal outer dynein arms in situ by electron tomography.

    Science.gov (United States)

    Lupetti, Pietro; Lanzavecchia, Salvatore; Mercati, David; Cantele, Francesca; Dallai, Romano; Mencarelli, Caterina

    2005-10-01

    We present here for the first time a 3D reconstruction of in situ axonemal outer dynein arms. This reconstruction has been obtained by electron tomography applied to a series of tilted images collected from metal replicas of rapidly frozen, cryofractured, and metal-replicated sperm axonemes of the cecidomid dipteran Monarthropalpus flavus. This peculiar axonemal model consists of several microtubular laminae that proved to be particularly suitable for this type of analysis. These laminae are sufficiently planar to allow the visualization of many dynein molecules within the same fracture face, allowing us to recover a significant number of equivalent objects and to improve the signal-to-noise ratio of the reconstruction by applying advanced averaging protocols. The 3D model we obtained showed the following interesting structural features: First, each dynein arm has two head domains that are almost parallel and are obliquely oriented with respect to the longitudinal axis of microtubules. The two heads are therefore positioned at different distances from the surface of the A-tubule. Second, each head domain consists of a series of globular subdomains that are positioned on the same plane. Third, a stalk domain originates as a conical region from the proximal head and ends with a small globular domain that contacts the B-tubule. Fourth, the stem region comprises several globular subdomains and presents two distinct points of anchorage to the surface of the A-tubule. Finally, and most importantly, contrary to what has been observed in isolated dynein molecules adsorbed to flat surfaces, the stalk and the stem domains are not in the same plane as the head.

  8. Three-dimensional imaging of individual point defects using selective detection angles in annular dark field scanning transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Jared M.; Im, Soohyun; Windl, Wolfgang; Hwang, Jinwoo, E-mail: hwang.458@osu.edu

    2017-01-15

    We propose a new scanning transmission electron microscopy (STEM) technique that can realize the three-dimensional (3D) characterization of vacancies, lighter and heavier dopants with high precision. Using multislice STEM imaging and diffraction simulations of β-Ga{sub 2}O{sub 3} and SrTiO{sub 3}, we show that selecting a small range of low scattering angles can make the contrast of the defect-containing atomic columns substantially more depth-dependent. The origin of the depth-dependence is the de-channeling of electrons due to the existence of a point defect in the atomic column, which creates extra “ripples” at low scattering angles. The highest contrast of the point defect can be achieved when the de-channeling signal is captured using the 20–40 mrad detection angle range. The effect of sample thickness, crystal orientation, local strain, probe convergence angle, and experimental uncertainty to the depth-dependent contrast of the point defect will also be discussed. The proposed technique therefore opens new possibilities for highly precise 3D structural characterization of individual point defects in functional materials. - Highlights: • A new electron microscopy technique that can visualize 3D position of point defect is proposed. • The technique relies on the electron de-channeling signals at low scattering angles. • The technique enables precise determination of the depth of vacancies and lighter impurity atoms.

  9. Three dimensional system integration

    CERN Document Server

    Papanikolaou, Antonis; Radojcic, Riko

    2010-01-01

    Three-dimensional (3D) integrated circuit (IC) stacking is the next big step in electronic system integration. It enables packing more functionality, as well as integration of heterogeneous materials, devices, and signals, in the same space (volume). This results in consumer electronics (e.g., mobile, handheld devices) which can run more powerful applications, such as full-length movies and 3D games, with longer battery life. This technology is so promising that it is expected to be a mainstream technology a few years from now, less than 10-15 years from its original conception. To achieve thi

  10. Three-dimensional organization of pKi-67: a comparative fluorescence and electron tomography study using FluoroNanogold.

    Science.gov (United States)

    Cheutin, Thierry; O'Donohue, Marie-Françoise; Beorchia, Adrien; Klein, Christophe; Kaplan, Hervé; Ploton, Dominique

    2003-11-01

    The monoclonal antibody (MAb) Ki-67 is routinely used in clinical studies to estimate the growth fraction of tumors. However, the role of pKi-67, the protein detected by the Ki-67 MAb, remains elusive, although some biochemical data strongly suggest that it might organize chromatin. To better understand the functional organization of pKi-67, we studied its three-dimensional distribution in interphase cells by confocal microscopy and electron tomography. FluoroNanogold, a single probe combining a dense marker with a fluorescent dye, was used to investigate pKi-67 organization at the optical and ultrastructural levels. Observation by confocal microscopy followed by 3D reconstruction showed that pKi-67 forms a shell around the nucleoli. Double labeling experiments revealed that pKi-67 co-localizes with perinucleolar heterochromatin. Electron microscopy studies confirmed this close association and demonstrated that pKi-67 is located neither in the fibrillar nor in the granular components of the nucleolus. Finally, spatial analyses by electron tomography showed that pKi-67 forms cords 250-300 nm in diameter, which are themselves composed of 30-50-nm-thick fibers. These detailed comparative in situ analyses strongly suggest the involvement of pKi-67 in the higher-order organization of perinucleolar chromatin.

  11. Global Three-Dimensional Ionospheric Data Assimilation Model Using Ground-based GPS and Radio Occultation Total Electron Content

    Science.gov (United States)

    Jann-Yenq Liu, Tiger; Lin, Chi-Yen; Matsuo, Tomoko; Lin, Charles C. H.; Tsai, Ho-Fang; Chen, Chao-Yen

    2017-04-01

    An ionospheric data assimilation approach presented here is based on the Gauss-Markov Kalman filter with International Reference Ionosphere (IRI) as the background model and designed to assimilate the total electron content (TEC) observed from ground-based GPS receivers and space-based radio occultation (RO) of FORMOSAT-3/COSMIC (F3/C) or FORMOSAT-7/COSMIC-2 (F7/C2). The Kalman filter consists of the forecast step according to Gauss-Markov process and measurement update step. Observing System Simulation Experiments (OSSEs) show that the Gauss-Markov Kalman filter procedure can increase the accuracy of the data assimilation analysis over the procedure consisting of the measurement update step alone. Moreover, in comparing to F3/C, the dense F7/C2 RO observation can further increase the model accuracy significantly. Validating the data assimilation results with the vertical TEC in Global Ionosphere Maps and that derived from ground-based GPS measurements, as well as the ionospheric F2-peak height and electron density sounded by ionosondes is also carried out. Both the OSSE results and the observation validations confirm that the developed data assimilation model can be used to reconstruct the three-dimensional electron density in the ionosphere satisfactorily.

  12. Spectral Interferometry with Electron Microscopes

    Science.gov (United States)

    Talebi, Nahid

    2016-01-01

    Interference patterns are not only a defining characteristic of waves, but also have several applications; characterization of coherent processes and holography. Spatial holography with electron waves, has paved the way towards space-resolved characterization of magnetic domains and electrostatic potentials with angstrom spatial resolution. Another impetus in electron microscopy has been introduced by ultrafast electron microscopy which uses pulses of sub-picosecond durations for probing a laser induced excitation of the sample. However, attosecond temporal resolution has not yet been reported, merely due to the statistical distribution of arrival times of electrons at the sample, with respect to the laser time reference. This is however, the very time resolution which will be needed for performing time-frequency analysis. These difficulties are addressed here by proposing a new methodology to improve the synchronization between electron and optical excitations through introducing an efficient electron-driven photon source. We use focused transition radiation of the electron as a pump for the sample. Due to the nature of transition radiation, the process is coherent. This technique allows us to perform spectral interferometry with electron microscopes, with applications in retrieving the phase of electron-induced polarizations and reconstructing dynamics of the induced vector potential. PMID:27649932

  13. Electron and ion kinetics in three-dimensional confined microwave-induced microplasmas at low gas pressures

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jiali; Yu, Xinhai, E-mail: yxhh@ecust.edu.cn; Tu, Shan-Tung; Wang, Zhengdong [Key Laboratory of Pressure Systems and Safety, Ministry of Education, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai (China); Wang, Zhenyu [Integrated Micro & Nano System Engineering Center, School of Software and Microelectronics at Wuxi, Peking University (China)

    2016-04-15

    The effects of the gas pressure (p{sub g}), microcavity height (t), Au vapor addition, and microwave frequency on the properties of three-dimensional confined microwave-induced microplasmas were discussed in light of simulation results of a glow microdischarge in a three-dimensional microcavity (diameter d{sub h} = 1000 μm) driven at constant voltage loading on the drive electrode (V{sub rf}) of 180 V. The simulation was performed using the PIC/MCC method, whose results were experimentally verified. In all the cases we investigated in this study, the microplasmas were in the γ-mode. When p{sub g} increased, the maximum electron (n{sub e}) or ion density (n{sub Ar+}) distributions turned narrow and close to the discharge gap due to the decrease in the mean free path of the secondary electron emission (SEE) electrons (λ{sub SEE-e}). The peak n{sub e} and n{sub Ar+} were not a monotonic function of p{sub g}, resulting from the two conflicting effects of p{sub g} on n{sub e} and n{sub Ar+}. The impact of ions on the electrode was enhanced when p{sub g} increased. This was determined after comparing the results of ion energy distribution function (IEDFs) at various p{sub g}. The effects of t on the peaks and distributions of n{sub e} and n{sub Ar+} were negligible in the range of t from 1.0 to 3.0 mm. The minimum t of 0.6 mm for a steady glow discharge was predicted for p{sub g} of 800 Pa and V{sub rf} of 180 V. The Au vapor addition increased the peaks of n{sub e} and n{sub Ar+}, due to the lower ionization voltage of Au atom. The acceleration of ions in the sheaths was intensified with the addition of Au vapor because of the increased potential difference in the sheath at the drive electrode.

  14. Electron and ion kinetics in three-dimensional confined microwave-induced microplasmas at low gas pressures

    International Nuclear Information System (INIS)

    Tang, Jiali; Yu, Xinhai; Tu, Shan-Tung; Wang, Zhengdong; Wang, Zhenyu

    2016-01-01

    The effects of the gas pressure (p_g), microcavity height (t), Au vapor addition, and microwave frequency on the properties of three-dimensional confined microwave-induced microplasmas were discussed in light of simulation results of a glow microdischarge in a three-dimensional microcavity (diameter d_h = 1000 μm) driven at constant voltage loading on the drive electrode (V_r_f) of 180 V. The simulation was performed using the PIC/MCC method, whose results were experimentally verified. In all the cases we investigated in this study, the microplasmas were in the γ-mode. When p_g increased, the maximum electron (n_e) or ion density (n_A_r_+) distributions turned narrow and close to the discharge gap due to the decrease in the mean free path of the secondary electron emission (SEE) electrons (λ_S_E_E_-_e). The peak n_e and n_A_r_+ were not a monotonic function of p_g, resulting from the two conflicting effects of p_g on n_e and n_A_r_+. The impact of ions on the electrode was enhanced when p_g increased. This was determined after comparing the results of ion energy distribution function (IEDFs) at various p_g. The effects of t on the peaks and distributions of n_e and n_A_r_+ were negligible in the range of t from 1.0 to 3.0 mm. The minimum t of 0.6 mm for a steady glow discharge was predicted for p_g of 800 Pa and V_r_f of 180 V. The Au vapor addition increased the peaks of n_e and n_A_r_+, due to the lower ionization voltage of Au atom. The acceleration of ions in the sheaths was intensified with the addition of Au vapor because of the increased potential difference in the sheath at the drive electrode.

  15. Three-dimensional hollow graphene efficiently promotes electron transfer of Ag3PO4 for photocatalytically eliminating phenol

    Science.gov (United States)

    Song, Shaoqing; Meng, Aiyun; Jiang, Shujuan; Cheng, Bei

    2018-06-01

    The effective transport of photo-induced carriers over semiconductor photocatalyst is critical for enhancing the photocatalytic performance under light excitation. Although oxidized graphene (GO) and/or reduced graphene oxide (rGO) has been used as cocatalyst to promote the transfer and utilization of electrons, however, random diffusion and transfer of photo-induced charges are inevitable from all sides over these actual graphene owing to the limitation of the preparation process and theory. Herein, we utilized three-dimensional hollow carbon graphene (HCG) to promote the efficient electron transfer of Ag3PO4 in the photocatalytic process. Owing to the confinement-induced electron field of HCG, the constructed HCG-Ag3PO4 photocatalytic system demonstrated the enhanced visible-light adsorption, improved transfer of photo-induced charges, and suitable redox potentials as revealed by transient photo-current spectroscopic, surface photovoltage spectroscopy, and electron paramagnetic resonance (EPR). EPR spectra of oxygen species and gas chromatography-mass spectra exhibited high efficiency activity over HCG-Ag3PO4 with Z-scheme photocatalytic mechanism for phenol decomposition by reaction between hexanoic acid and radOH and radO2-. It is noteworthy that photocatalytic performance over optimal HCG-Ag3PO4 is 6, 3.43, 1.92 times of pristine Ag3PO4, GO-Ag3PO4, and rGO-Ag3PO4, respectively. The results may supply a novel perspective to enhance transfer of photo-induced charges for the promotion of photocatalytic technology.

  16. Electron microscopy and three-dimensional reconstruction of native thin filaments reveal species-specific differences in regulatory strand densities

    Energy Technology Data Exchange (ETDEWEB)

    Cammarato, Anthony, E-mail: acammara@burnham.org [Department of Physiology and Biophysics, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118 (United States); Craig, Roger [Department of Cell Biology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655 (United States); Lehman, William [Department of Physiology and Biophysics, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118 (United States)

    2010-01-01

    Throughout the animal kingdom striated muscle contraction is regulated by the thin filament troponin-tropomyosin complex. Homologous regulatory components are shared among vertebrate and arthropod muscles; however, unique protein extensions and/or components characterize the latter. The Troponin T (TnT) isoforms of Drosophila indirect flight and tarantula femur muscle for example contain distinct C-terminal extensions and are {approx}20% larger overall than their vertebrate counterpart. Using electron microscopy and three-dimensional helical reconstruction of native Drosophila, tarantula and frog muscle thin filaments we have identified species-specific differences in tropomyosin regulatory strand densities. The strands on the arthropod thin filaments were significantly larger in diameter than those from vertebrates, although not significantly different from each other. These findings reflect differences in the regulatory troponin-tropomyosin complex, which are likely due to the larger TnT molecules aligning and extending along much of the tropomyosin strands' length. Such an arrangement potentially alters the physical properties of the regulatory strands and may help establish contractile characteristics unique to certain arthropod muscles.

  17. [COMPUTER ASSISTED DESIGN AND ELECTRON BEAMMELTING RAPID PROTOTYPING METAL THREE-DIMENSIONAL PRINTING TECHNOLOGY FOR PREPARATION OF INDIVIDUALIZED FEMORAL PROSTHESIS].

    Science.gov (United States)

    Liu, Hongwei; Weng, Yiping; Zhang, Yunkun; Xu, Nanwei; Tong, Jing; Wang, Caimei

    2015-09-01

    To study the feasibility of preparation of the individualized femoral prosthesis through computer assisted design and electron beammelting rapid prototyping (EBM-RP) metal three-dimensional (3D) printing technology. One adult male left femur specimen was used for scanning with 64-slice spiral CT; tomographic image data were imported into Mimics15.0 software to reconstruct femoral 3D model, then the 3D model of individualized femoral prosthesis was designed through UG8.0 software. Finally the 3D model data were imported into EBM-RP metal 3D printer to print the individualized sleeve. According to the 3D model of individualized prosthesis, customized sleeve was successfully prepared through the EBM-RP metal 3D printing technology, assembled with the standard handle component of SR modular femoral prosthesis to make the individualized femoral prosthesis. Customized femoral prosthesis accurately matching with metaphyseal cavity can be designed through the thin slice CT scanning and computer assisted design technology. Titanium alloy personalized prosthesis with complex 3D shape, pore surface, and good matching with metaphyseal cavity can be manufactured by the technology of EBM-RP metal 3D printing, and the technology has convenient, rapid, and accurate advantages.

  18. High-performance blob-based iterative three-dimensional reconstruction in electron tomography using multi-GPUs

    Directory of Open Access Journals (Sweden)

    Wan Xiaohua

    2012-06-01

    Full Text Available Abstract Background Three-dimensional (3D reconstruction in electron tomography (ET has emerged as a leading technique to elucidate the molecular structures of complex biological specimens. Blob-based iterative methods are advantageous reconstruction methods for 3D reconstruction in ET, but demand huge computational costs. Multiple graphic processing units (multi-GPUs offer an affordable platform to meet these demands. However, a synchronous communication scheme between multi-GPUs leads to idle GPU time, and a weighted matrix involved in iterative methods cannot be loaded into GPUs especially for large images due to the limited available memory of GPUs. Results In this paper we propose a multilevel parallel strategy combined with an asynchronous communication scheme and a blob-ELLR data structure to efficiently perform blob-based iterative reconstructions on multi-GPUs. The asynchronous communication scheme is used to minimize the idle GPU time so as to asynchronously overlap communications with computations. The blob-ELLR data structure only needs nearly 1/16 of the storage space in comparison with ELLPACK-R (ELLR data structure and yields significant acceleration. Conclusions Experimental results indicate that the multilevel parallel scheme combined with the asynchronous communication scheme and the blob-ELLR data structure allows efficient implementations of 3D reconstruction in ET on multi-GPUs.

  19. Electron microscopy and three-dimensional reconstruction of native thin filaments reveal species-specific differences in regulatory strand densities

    International Nuclear Information System (INIS)

    Cammarato, Anthony; Craig, Roger; Lehman, William

    2010-01-01

    Throughout the animal kingdom striated muscle contraction is regulated by the thin filament troponin-tropomyosin complex. Homologous regulatory components are shared among vertebrate and arthropod muscles; however, unique protein extensions and/or components characterize the latter. The Troponin T (TnT) isoforms of Drosophila indirect flight and tarantula femur muscle for example contain distinct C-terminal extensions and are ∼20% larger overall than their vertebrate counterpart. Using electron microscopy and three-dimensional helical reconstruction of native Drosophila, tarantula and frog muscle thin filaments we have identified species-specific differences in tropomyosin regulatory strand densities. The strands on the arthropod thin filaments were significantly larger in diameter than those from vertebrates, although not significantly different from each other. These findings reflect differences in the regulatory troponin-tropomyosin complex, which are likely due to the larger TnT molecules aligning and extending along much of the tropomyosin strands' length. Such an arrangement potentially alters the physical properties of the regulatory strands and may help establish contractile characteristics unique to certain arthropod muscles.

  20. Validation of Spherically Symmetric Inversion by Use of a Tomographically Reconstructed Three-Dimensional Electron Density of the Solar Corona

    Science.gov (United States)

    Wang, Tongjiang; Davila, Joseph M.

    2014-01-01

    Determining the coronal electron density by the inversion of white-light polarized brightness (pB) measurements by coronagraphs is a classic problem in solar physics. An inversion technique based on the spherically symmetric geometry (spherically symmetric inversion, SSI) was developed in the 1950s and has been widely applied to interpret various observations. However, to date there is no study of the uncertainty estimation of this method. We here present the detailed assessment of this method using a three-dimensional (3D) electron density in the corona from 1.5 to 4 solar radius as a model, which is reconstructed by a tomography method from STEREO/COR1 observations during the solar minimum in February 2008 (Carrington Rotation, CR 2066).We first show in theory and observation that the spherically symmetric polynomial approximation (SSPA) method and the Van de Hulst inversion technique are equivalent. Then we assess the SSPA method using synthesized pB images from the 3D density model, and find that the SSPA density values are close to the model inputs for the streamer core near the plane of the sky (POS) with differences generally smaller than about a factor of two; the former has the lower peak but extends more in both longitudinal and latitudinal directions than the latter. We estimate that the SSPA method may resolve the coronal density structure near the POS with angular resolution in longitude of about 50 deg. Our results confirm the suggestion that the SSI method is applicable to the solar minimum streamer (belt), as stated in some previous studies. In addition, we demonstrate that the SSPA method can be used to reconstruct the 3D coronal density, roughly in agreement with the reconstruction by tomography for a period of low solar activity (CR 2066). We suggest that the SSI method is complementary to the 3D tomographic technique in some cases, given that the development of the latter is still an ongoing research effort.

  1. Electrochemically Functionalized Seamless Three-Dimensional Graphene-Carbon Nanotube Hybrid for Direct Electron Transfer of Glucose Oxidase and Bioelectrocatalysis.

    Science.gov (United States)

    Terse-Thakoor, Trupti; Komori, Kikuo; Ramnani, Pankaj; Lee, Ilkeun; Mulchandani, Ashok

    2015-12-01

    Three-dimensional seamless chemical vapor deposition (CVD) grown graphene-carbon nanotubes (G-CNT) hybrid film has been studied for its potential in achieving direct electron transfer (DET) of glucose oxidase (GOx) and its bioelectrocatalytic activity in glucose detection. A two-step CVD method was employed for the synthesis of seamless G-CNT hybrid film where CNTs are grown on already grown graphene film on copper foil using iron as a catalyst. Physical characterization using SEM and TEM show uniform dense coverage of multiwall carbon nanotubes (MWCNT) grown directly on graphene with seamless contacts. The G-CNT hybrid film was electrochemically modified to introduce oxygenated functional groups for DET favorable immobilization of GOx. Pristine and electrochemically functionalized G-CNT film was characterized by electrochemical impedance spectroscopy (EIS), cyclic voltammetry, X-ray photoelectron-spectroscopy, and Raman spectroscopy. The DET between GOx and electrochemically oxidized G-CNT electrode was studied using cyclic voltammetry which showed a pair of well-defined and quasi-reversible redox peaks with a formal potential of -459 mV at pH 7 corresponding to the redox site of GOx. The constructed electrode detected glucose concentration over the clinically relevant range of 2-8 mM with the highest sensitivity of 19.31 μA/mM/cm(2) compared to reported composite hybrid electrodes of graphene oxide and CNTs. Electrochemically functionalized CVD grown seamless G-CNT structure used in this work has potential to be used for development of artificial mediatorless redox enzyme based biosensors and biofuel cells.

  2. Design of a transmission electron positron microscope

    International Nuclear Information System (INIS)

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

    2003-01-01

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

  3. Three-dimensional portable document format: a simple way to present 3-dimensional data in an electronic publication

    NARCIS (Netherlands)

    Danz, J.C.; Katsaros, C.

    2011-01-01

    Three-dimensional (3D) models of teeth and soft and hard tissues are tessellated surfaces used for diagnosis, treatment planning, appliance fabrication, outcome evaluation, and research. In scientific publications or communications with colleagues, these 3D data are often reduced to 2-dimensional

  4. Exact and variational calculations of eigenmodes for three-dimensional free electron laser interaction with a warm electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Xie, M. [Lawrence Berkeley Lab., CA (United States)

    1995-12-31

    I present an exact calculation of free-electron-laser (FEL) eigenmodes (fundamental as well as higher order modes) in the exponential-gain regime. These eigenmodes specify transverse profiles and exponential growth rates of the laser field, and they are self-consistent solutions of the coupled Maxwell-Vlasov equations describing the FEL interaction taking into account the effects due to energy spread, emittance and betatron oscillations of the electron beam, and diffraction and guiding of the laser field. The unperturbed electron distribution is assumed to be of Gaussian shape in four dimensional transverse phase space and in the energy variable, but uniform in longitudinal coordinate. The focusing of the electron beam is assumed to be matched to the natural wiggler focusing in both transverse planes. With these assumptions the eigenvalue problem can be reduced to a numerically manageable integral equation and solved exactly with a kernel iteration method. An approximate, but more efficient solution of the integral equation is also obtained for the fundamental mode by a variational technique, which is shown to agree well with the exact results. Furthermore, I present a handy formula, obtained from interpolating the numerical results, for a quick calculation of FEL exponential growth rate. Comparisons with simulation code TDA will also be presented. Application of these solutions to the design and multi-dimensional parameter space optimization for an X-ray free electron laser driven by SLAC linac will be demonstrated. In addition, a rigorous analysis of transverse mode degeneracy and hence the transverse coherence of the X-ray FEL will be presented based on the exact solutions of the higher order guided modes.

  5. Scanning Electron Microscope Analysis System

    Data.gov (United States)

    Federal Laboratory Consortium — This facility provides the capability to examine surfaces microscopically with high resolution (5 nanometers), perform micro chemical analyses of these surfaces, and...

  6. Low-resistance gateless high electron mobility transistors using three-dimensional inverted pyramidal AlGaN/GaN surfaces

    International Nuclear Information System (INIS)

    So, Hongyun; Senesky, Debbie G.

    2016-01-01

    In this letter, three-dimensional gateless AlGaN/GaN high electron mobility transistors (HEMTs) were demonstrated with 54% reduction in electrical resistance and 73% increase in surface area compared with conventional gateless HEMTs on planar substrates. Inverted pyramidal AlGaN/GaN surfaces were microfabricated using potassium hydroxide etched silicon with exposed (111) surfaces and metal-organic chemical vapor deposition of coherent AlGaN/GaN thin films. In addition, electrical characterization of the devices showed that a combination of series and parallel connections of the highly conductive two-dimensional electron gas along the pyramidal geometry resulted in a significant reduction in electrical resistance at both room and high temperatures (up to 300 °C). This three-dimensional HEMT architecture can be leveraged to realize low-power and reliable power electronics, as well as harsh environment sensors with increased surface area

  7. Low-resistance gateless high electron mobility transistors using three-dimensional inverted pyramidal AlGaN/GaN surfaces

    Energy Technology Data Exchange (ETDEWEB)

    So, Hongyun, E-mail: hyso@stanford.edu [Department of Aeronautics and Astronautics, Stanford University, Stanford, California 94305 (United States); Senesky, Debbie G. [Department of Aeronautics and Astronautics, Stanford University, Stanford, California 94305 (United States); Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2016-01-04

    In this letter, three-dimensional gateless AlGaN/GaN high electron mobility transistors (HEMTs) were demonstrated with 54% reduction in electrical resistance and 73% increase in surface area compared with conventional gateless HEMTs on planar substrates. Inverted pyramidal AlGaN/GaN surfaces were microfabricated using potassium hydroxide etched silicon with exposed (111) surfaces and metal-organic chemical vapor deposition of coherent AlGaN/GaN thin films. In addition, electrical characterization of the devices showed that a combination of series and parallel connections of the highly conductive two-dimensional electron gas along the pyramidal geometry resulted in a significant reduction in electrical resistance at both room and high temperatures (up to 300 °C). This three-dimensional HEMT architecture can be leveraged to realize low-power and reliable power electronics, as well as harsh environment sensors with increased surface area.

  8. Bright-field scanning confocal electron microscopy using a double aberration-corrected transmission electron microscope.

    Science.gov (United States)

    Wang, Peng; Behan, Gavin; Kirkland, Angus I; Nellist, Peter D; Cosgriff, Eireann C; D'Alfonso, Adrian J; Morgan, Andrew J; Allen, Leslie J; Hashimoto, Ayako; Takeguchi, Masaki; Mitsuishi, Kazutaka; Shimojo, Masayuki

    2011-06-01

    Scanning confocal electron microscopy (SCEM) offers a mechanism for three-dimensional imaging of materials, which makes use of the reduced depth of field in an aberration-corrected transmission electron microscope. The simplest configuration of SCEM is the bright-field mode. In this paper we present experimental data and simulations showing the form of bright-field SCEM images. We show that the depth dependence of the three-dimensional image can be explained in terms of two-dimensional images formed in the detector plane. For a crystalline sample, this so-called probe image is shown to be similar to a conventional diffraction pattern. Experimental results and simulations show how the diffracted probes in this image are elongated in thicker crystals and the use of this elongation to estimate sample thickness is explored. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. Three dimensional strained semiconductors

    Science.gov (United States)

    Voss, Lars; Conway, Adam; Nikolic, Rebecca J.; Leao, Cedric Rocha; Shao, Qinghui

    2016-11-08

    In one embodiment, an apparatus includes a three dimensional structure comprising a semiconductor material, and at least one thin film in contact with at least one exterior surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the three dimensional structure. In another embodiment, a method includes forming a three dimensional structure comprising a semiconductor material, and depositing at least one thin film on at least one surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the structure.

  10. Bright-field scanning confocal electron microscopy using a double aberration-corrected transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peng; Behan, Gavin; Kirkland, Angus I. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Nellist, Peter D., E-mail: peter.nellist@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Cosgriff, Eireann C.; D' Alfonso, Adrian J.; Morgan, Andrew J.; Allen, Leslie J. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Hashimoto, Ayako [Advanced Nano-characterization Center, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba 305-0003 (Japan); Takeguchi, Masaki [Advanced Nano-characterization Center, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba 305-0003 (Japan); High Voltage Electron Microscopy Station, NIMS, 3-13 Sakura, Tsukuba 305-0003 (Japan); Mitsuishi, Kazutaka [Advanced Nano-characterization Center, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba 305-0003 (Japan); Quantum Dot Research Center, NIMS, 3-13 Sakura, Tsukuba 305-0003 (Japan); Shimojo, Masayuki [High Voltage Electron Microscopy Station, NIMS, 3-13 Sakura, Tsukuba 305-0003 (Japan); Advanced Science Research Laboratory, Saitama Institute of Technology, 1690 Fusaiji, Fukaya 369-0293 (Japan)

    2011-06-15

    Scanning confocal electron microscopy (SCEM) offers a mechanism for three-dimensional imaging of materials, which makes use of the reduced depth of field in an aberration-corrected transmission electron microscope. The simplest configuration of SCEM is the bright-field mode. In this paper we present experimental data and simulations showing the form of bright-field SCEM images. We show that the depth dependence of the three-dimensional image can be explained in terms of two-dimensional images formed in the detector plane. For a crystalline sample, this so-called probe image is shown to be similar to a conventional diffraction pattern. Experimental results and simulations show how the diffracted probes in this image are elongated in thicker crystals and the use of this elongation to estimate sample thickness is explored. -- Research Highlights: {yields} The confocal probe image in a scanning confocal electron microscopy image reveals information about the thickness and height of the crystalline layer. {yields} The form of the contrast in a three-dimensional bright-field scanning confocal electron microscopy image can be explained in terms of the confocal probe image. {yields} Despite the complicated form of the contrast in bright-field scanning confocal electron microscopy, we see that depth information is transferred on a 10 nm scale.

  11. Focusing peculiarities of ion-channel guiding on a relativistic electron beam in a free-electron laser with a three-dimensional wiggler

    International Nuclear Information System (INIS)

    Ouyang, Zhengbiao; Zhang, Shi-Chang

    2014-01-01

    In a free-electron laser the ‘natural focusing’ effect of a three-dimensional wiggler is too weak to confine the transport of a relativistic electron beam when the beam has a high current and consequently an external focusing system is often needed. In this paper we study the focusing peculiarities of an ion-channel guide field on an electron beam. Nonlinear simulations of an electron beam transport show that, compared to an axial guide magnetic field, the ion-channel guide field results in smaller velocity–space and configuration–space spreads. The intrinsic mechanism of this physical phenomenon is that the ion-channel guide field confines the trajectory of the electron motion resulting in a smaller instantaneous curvature radius and a slighter curvature-center excursion than an axial guide magnetic field does. It is also found that, unlike with an axial guide magnetic field, over-focusing may occur if the ion-channel guide field is too strong. (paper)

  12. Electron Microscope Center Opens at Berkeley.

    Science.gov (United States)

    Robinson, Arthur L.

    1981-01-01

    A 1.5-MeV High Voltage Electron Microscope has been installed at the Lawrence Berkeley Laboratory which will help materials scientists and biologists study samples in more true-to-life situations. A 1-MeV Atomic Resolution Microscope will be installed at the same location in two years which will allow scientists to distinguish atoms. (DS)

  13. Designs for a quantum electron microscope.

    Science.gov (United States)

    Kruit, P; Hobbs, R G; Kim, C-S; Yang, Y; Manfrinato, V R; Hammer, J; Thomas, S; Weber, P; Klopfer, B; Kohstall, C; Juffmann, T; Kasevich, M A; Hommelhoff, P; Berggren, K K

    2016-05-01

    One of the astounding consequences of quantum mechanics is that it allows the detection of a target using an incident probe, with only a low probability of interaction of the probe and the target. This 'quantum weirdness' could be applied in the field of electron microscopy to generate images of beam-sensitive specimens with substantially reduced damage to the specimen. A reduction of beam-induced damage to specimens is especially of great importance if it can enable imaging of biological specimens with atomic resolution. Following a recent suggestion that interaction-free measurements are possible with electrons, we now analyze the difficulties of actually building an atomic resolution interaction-free electron microscope, or "quantum electron microscope". A quantum electron microscope would require a number of unique components not found in conventional transmission electron microscopes. These components include a coherent electron beam-splitter or two-state-coupler, and a resonator structure to allow each electron to interrogate the specimen multiple times, thus supporting high success probabilities for interaction-free detection of the specimen. Different system designs are presented here, which are based on four different choices of two-state-couplers: a thin crystal, a grating mirror, a standing light wave and an electro-dynamical pseudopotential. Challenges for the detailed electron optical design are identified as future directions for development. While it is concluded that it should be possible to build an atomic resolution quantum electron microscope, we have also identified a number of hurdles to the development of such a microscope and further theoretical investigations that will be required to enable a complete interpretation of the images produced by such a microscope. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  14. Three dimensional canonical transformations

    International Nuclear Information System (INIS)

    Tegmen, A.

    2010-01-01

    A generic construction of canonical transformations is given in three-dimensional phase spaces on which Nambu bracket is imposed. First, the canonical transformations are defined as based on cannonade transformations. Second, it is shown that determination of the generating functions and the transformation itself for given generating function is possible by solving correspondent Pfaffian differential equations. Generating functions of type are introduced and all of them are listed. Infinitesimal canonical transformations are also discussed as the complementary subject. Finally, it is shown that decomposition of canonical transformations is also possible in three-dimensional phase spaces as in the usual two-dimensional ones.

  15. Three-dimensional neuroimaging

    International Nuclear Information System (INIS)

    Toga, A.W.

    1990-01-01

    This book reports on new neuroimaging technologies that are revolutionizing the study of the brain be enabling investigators to visualize its structure and entire pattern of functional activity in three dimensions. The book provides a theoretical and practical explanation of the new science of creating three-dimensional computer images of the brain. The coverage includes a review of the technology and methodology of neuroimaging, the instrumentation and procedures, issues of quantification, analytic protocols, and descriptions of neuroimaging systems. Examples are given to illustrate the use of three-dimensional enuroimaging to quantitate spatial measurements, perform analysis of autoradiographic and histological studies, and study the relationship between brain structure and function

  16. Quantification of incisal tooth wear in upper anterior teeth: conventional vs new method using toolmakers microscope and a three-dimensional measuring technique.

    Science.gov (United States)

    Al-Omiri, Mahmoud K; Sghaireen, Mohd G; Alzarea, Bader K; Lynch, Edward

    2013-12-01

    This study aimed to quantify tooth wear in upper anterior teeth using a new CAD-CAM Laser scanning machine, tool maker microscope and conventional tooth wear index. Fifty participants (25 males and 25 females, mean age = 25 ± 4 years) were assessed for incisal tooth wear of upper anterior teeth using Smith and Knight clinical tooth wear index (TWI) on two occasions, the study baseline and 1 year later. Stone dies for each tooth were prepared and scanned using the CAD-CAM Laser Cercon System. Scanned images were printed and examined under a toolmaker microscope to quantify tooth wear and then the dies were directly assessed under the microscope to measure tooth wear. The Wilcoxon Signed Ranks Test was used to analyze the data. TWI scores for incisal edges were 0-3 and were similar at both occasions. Score 4 was not detected. Wear values measured by directly assessing the dies under the toolmaker microscope (range = 113 - 150 μm, mean = 130 ± 20 μm) were significantly more than those measured from Cercon Digital Machine images (range=52-80 μm, mean = 68 ± 23 μm) and both showed significant differences between the two occasions. Wear progression in upper anterior teeth was effectively detected by directly measuring the dies or the images of dies under toolmaker microscope. Measuring the dies of worn dentition directly under tool maker microscope enabled detection of wear progression more accurately than measuring die images obtained with Cercon Digital Machine. Conventional method was the least sensitive for tooth wear quantification and was unable to identify wear progression in most cases. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Electron waves under the microscope

    International Nuclear Information System (INIS)

    Geim, A.

    2000-01-01

    If I were to explain to you what a velociraptor is, I would probably say that it looks like a small Tyrannosaurus rex and is about the same size as a dog. But what if you have never seen a picture of a T. rex? Every teacher or physicist trying to explain to students w hat an electron is'' has a similar, but more severe, problem. It usually takes months, if not years, of physics training to become familiar with imaginary pictures of electrons and then learn how to use them. Moreover, physicists need many different images depending on the phenomenon they want to address. However, in the last few years, real images of electron clouds and so-called quantum corrals have been taken. In the December issue of Physics World, Andrey Geim of the University of Manchester, UK, reveals how two recent experiments have allowed physicists to image electrons embedded deep inside semiconductors. (U.K.)

  18. Optical depth sectioning in the aberration-corrected scanning transmission and scanning confocal electron microscope

    International Nuclear Information System (INIS)

    Behan, G; Nellist, P D

    2008-01-01

    The use of spherical aberration correctors in the scanning transmission electron microscope (STEM) has the effect of reducing the depth of field of the microscope, making three-dimensional imaging of a specimen possible by optical sectioning. Depth resolution can be improved further by placing aberration correctors and lenses pre and post specimen to achieve an imaging mode known as scanning confocal electron microscopy (SCEM). We present the calculated incoherent point spread functions (PSF) and optical transfer functions (OTF) of a STEM and SCEM. The OTF for a STEM is shown to have a missing cone region which results in severe blurring along the optic axis, which can be especially severe for extended objects. We also present strategies for reconstruction of experimental data, such as three-dimensional deconvolution of the point spread function.

  19. Vibrational spectroscopy in the electron microscope.

    Science.gov (United States)

    Krivanek, Ondrej L; Lovejoy, Tracy C; Dellby, Niklas; Aoki, Toshihiro; Carpenter, R W; Rez, Peter; Soignard, Emmanuel; Zhu, Jiangtao; Batson, Philip E; Lagos, Maureen J; Egerton, Ray F; Crozier, Peter A

    2014-10-09

    Vibrational spectroscopies using infrared radiation, Raman scattering, neutrons, low-energy electrons and inelastic electron tunnelling are powerful techniques that can analyse bonding arrangements, identify chemical compounds and probe many other important properties of materials. The spatial resolution of these spectroscopies is typically one micrometre or more, although it can reach a few tens of nanometres or even a few ångströms when enhanced by the presence of a sharp metallic tip. If vibrational spectroscopy could be combined with the spatial resolution and flexibility of the transmission electron microscope, it would open up the study of vibrational modes in many different types of nanostructures. Unfortunately, the energy resolution of electron energy loss spectroscopy performed in the electron microscope has until now been too poor to allow such a combination. Recent developments that have improved the attainable energy resolution of electron energy loss spectroscopy in a scanning transmission electron microscope to around ten millielectronvolts now allow vibrational spectroscopy to be carried out in the electron microscope. Here we describe the innovations responsible for the progress, and present examples of applications in inorganic and organic materials, including the detection of hydrogen. We also demonstrate that the vibrational signal has both high- and low-spatial-resolution components, that the first component can be used to map vibrational features at nanometre-level resolution, and that the second component can be used for analysis carried out with the beam positioned just outside the sample--that is, for 'aloof' spectroscopy that largely avoids radiation damage.

  20. Three-dimensional characterization of bainitic microstructures in low-carbon high-strength low-alloy steel studied by electron backscatter diffraction

    International Nuclear Information System (INIS)

    Kang, J.S.; Seol, Jae-Bok; Park, C.G.

    2013-01-01

    We investigated the microstructural evolution of high strength low alloy steel, Fe–2.0Mn–0.15Si–0.05C (wt.%), by varying the continuous cooling rates from 1 K/s to 50 K/s using three-dimensional electron backscatter diffraction and transmission electron microscopy. Granular bainitic microstructure was prevalent under a slow cooling rate of 1–10 K/s, while lath-type bainite was dominant at a high cooling rate of 50 K/s. The acicular ferrite that was the major microstructure under the intermediate ranges of cooling rates between 10 K/s and 30 K/s was tangled with each other, leading to a three-dimensional interwoven structure with highly misoriented grains. Because of the formation of three-dimensional structures, we propose that the terms “acicular ferrite” and “bainitic ferrite,” which are currently used in steel, be replaced by the terms “interwoven acicular bainite” and “lath bainite,” respectively. Moreover, we also confirmed that the cooling rate is an important factor in determining whether bainitic microstructures occur in the form of granular bainite, interwoven bainite, or lath bainite. - Highlights: • The morphology of bainitic grains was characterized by 3D-EBSD. • The ‘interwoven bainite’ and ‘lath bainite’ were suggested. • Interwoven bainite consisted of lenticular plates that were interlinked in 3D regime. • The packets of lath bainite were aligned in a specific direction

  1. Three-dimensional characterization of bainitic microstructures in low-carbon high-strength low-alloy steel studied by electron backscatter diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Kang, J.S. [Department of Materials Science and Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Technical Research Laboratories, POSCO, Pohang 790-300 (Korea, Republic of); Seol, Jae-Bok, E-mail: j.seol@mpie.de [Max-Planck-Institut für Eisenforschung, Max-Planck-Str. 1, D-40237 Düsseldorf (Germany); Park, C.G. [Department of Materials Science and Engineering, POSTECH, Pohang 790-784 (Korea, Republic of)

    2013-05-15

    We investigated the microstructural evolution of high strength low alloy steel, Fe–2.0Mn–0.15Si–0.05C (wt.%), by varying the continuous cooling rates from 1 K/s to 50 K/s using three-dimensional electron backscatter diffraction and transmission electron microscopy. Granular bainitic microstructure was prevalent under a slow cooling rate of 1–10 K/s, while lath-type bainite was dominant at a high cooling rate of 50 K/s. The acicular ferrite that was the major microstructure under the intermediate ranges of cooling rates between 10 K/s and 30 K/s was tangled with each other, leading to a three-dimensional interwoven structure with highly misoriented grains. Because of the formation of three-dimensional structures, we propose that the terms “acicular ferrite” and “bainitic ferrite,” which are currently used in steel, be replaced by the terms “interwoven acicular bainite” and “lath bainite,” respectively. Moreover, we also confirmed that the cooling rate is an important factor in determining whether bainitic microstructures occur in the form of granular bainite, interwoven bainite, or lath bainite. - Highlights: • The morphology of bainitic grains was characterized by 3D-EBSD. • The ‘interwoven bainite’ and ‘lath bainite’ were suggested. • Interwoven bainite consisted of lenticular plates that were interlinked in 3D regime. • The packets of lath bainite were aligned in a specific direction.

  2. Three-dimensional fabrication and characterisation of core-shell nano-columns using electron beam patterning of Ge-doped SiO2

    DEFF Research Database (Denmark)

    Gontard, Lionel C.; Jinschek, Joerg R.; Ou, Haiyan

    2012-01-01

    electron tomography. The results show that transformations in insulators that have been subjected to intense irradiation using charged particles can be studied directly in three dimensions. The fabricated structures include core-shell nano-columns, sputtered regions, voids, and clusters. (C) 2012 American......A focused electron beam in a scanning transmission electron microscope (STEM) is used to create arrays of core-shell structures in a specimen of amorphous SiO2 doped with Ge. The same electron microscope is then used to measure the changes that occurred in the specimen in three dimensions using...

  3. Assessment of three-dimensional set-up errors in conventional head and neck radiotherapy using electronic portal imaging device

    International Nuclear Information System (INIS)

    Gupta, Tejpal; Chopra, Supriya; Kadam, Avinash; Agarwal, Jai Prakash; Devi, P Reena; Ghosh-Laskar, Sarbani; Dinshaw, Ketayun Ardeshir

    2007-01-01

    Set-up errors are an inherent part of radiation treatment process. Coverage of target volume is a direct function of set-up margins, which should be optimized to prevent inadvertent irradiation of adjacent normal tissues. The aim of this study was to evaluate three-dimensional (3D) set-up errors and propose optimum margins for target volume coverage in head and neck radiotherapy. The dataset consisted of 93 pairs of orthogonal simulator and corresponding portal images on which 558 point positions were measured to calculate translational displacement in 25 patients undergoing conventional head and neck radiotherapy with antero-lateral wedge pair technique. Mean displacements, population systematic (Σ) and random (σ) errors and 3D vector of displacement was calculated. Set-up margins were calculated using published margin recipes. The mean displacement in antero-posterior (AP), medio-lateral (ML) and supero-inferior (SI) direction was -0.25 mm (-6.50 to +7.70 mm), -0.48 mm (-5.50 to +7.80 mm) and +0.45 mm (-7.30 to +7.40 mm) respectively. Ninety three percent of the displacements were within 5 mm in all three cardinal directions. Population systematic (Σ) and random errors (σ) were 0.96, 0.98 and 1.20 mm and 1.94, 1.97 and 2.48 mm in AP, ML and SI direction respectively. The mean 3D vector of displacement was 3.84 cm. Using van Herk's formula, the clinical target volume to planning target volume margins were 3.76, 3.83 and 4.74 mm in AP, ML and SI direction respectively. The present study report compares well with published set-up error data relevant to head and neck radiotherapy practice. The set-up margins were <5 mm in all directions. Caution is warranted against adopting generic margin recipes as different margin generating recipes lead to a different probability of target volume coverage

  4. Spectroscopy of electron irradiated polymers in electron microscope

    International Nuclear Information System (INIS)

    Faraj, S.H.; Salih, S.M.

    1981-01-01

    The damage induced by energetic electrons in the course of irradiation of polymers in a transmission electron microscope was investigated spectroscopically. Damage on the molecular level has been detected at very low exposure doses. These effects have been induced by electron doses less than that received by the specimen when it is situated at its usual place of the specimen stage in the electron microscope by a factor of 1,000. (author)

  5. Transmission electron microscope studies of extraterrestrial materials

    Science.gov (United States)

    Keller, Lindsay P.

    1995-01-01

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

  6. Solution of the transport problem for electrons generated by an accelerator in the three-dimensional space of an absorber

    International Nuclear Information System (INIS)

    Vinogradov, V.V.

    1981-01-01

    The purpose of the investigation is the development of the method for calculation of distribution function of particles in the medium irradiated by electron beams. The process of particle transport was considered for infinite isotropic medium under the condition that all the particles, are concentrated in the source at first. The obtained solution can be used for investigation of particle transport through the substance with account of geometry of electron beam, particle distribution by the beam cross section, energy and angular spectra. The suggested approach can be applied for the solution of transport problems in which geometry of irradiated surface, presence of the field in the absorber should be taken into account that is significant when using electron accelerators in applied purposes [ru

  7. Designs for a quantum electron microscope

    International Nuclear Information System (INIS)

    Kruit, P.; Hobbs, R.G.; Kim, C-S.; Yang, Y.; Manfrinato, V.R.; Hammer, J.; Thomas, S.; Weber, P.; Klopfer, B.; Kohstall, C.; Juffmann, T.; Kasevich, M.A.; Hommelhoff, P.; Berggren, K.K.

    2016-01-01

    One of the astounding consequences of quantum mechanics is that it allows the detection of a target using an incident probe, with only a low probability of interaction of the probe and the target. This ‘quantum weirdness’ could be applied in the field of electron microscopy to generate images of beam-sensitive specimens with substantially reduced damage to the specimen. A reduction of beam-induced damage to specimens is especially of great importance if it can enable imaging of biological specimens with atomic resolution. Following a recent suggestion that interaction-free measurements are possible with electrons, we now analyze the difficulties of actually building an atomic resolution interaction-free electron microscope, or “quantum electron microscope”. A quantum electron microscope would require a number of unique components not found in conventional transmission electron microscopes. These components include a coherent electron beam-splitter or two-state-coupler, and a resonator structure to allow each electron to interrogate the specimen multiple times, thus supporting high success probabilities for interaction-free detection of the specimen. Different system designs are presented here, which are based on four different choices of two-state-couplers: a thin crystal, a grating mirror, a standing light wave and an electro-dynamical pseudopotential. Challenges for the detailed electron optical design are identified as future directions for development. While it is concluded that it should be possible to build an atomic resolution quantum electron microscope, we have also identified a number of hurdles to the development of such a microscope and further theoretical investigations that will be required to enable a complete interpretation of the images produced by such a microscope. - Highlights: • Quantum electron microscopy has the potential of reducing radiation damage. • QEM requires a fraction of the electron wave to pass through the sample

  8. Designs for a quantum electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Kruit, P., E-mail: p.kruit@tudelft.nl [Department of Imaging Physics, Delft University of Technology, Lorentzweg 1, 2628CJ Delft (Netherlands); Hobbs, R.G.; Kim, C-S.; Yang, Y.; Manfrinato, V.R. [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Hammer, J.; Thomas, S.; Weber, P. [Department of Physics, Friedrich Alexander University Erlangen-Nürnberg (FAU), Staudtstrasse 1, d-91058 Erlangen (Germany); Klopfer, B.; Kohstall, C.; Juffmann, T.; Kasevich, M.A. [Department of Physics, Stanford University, Stanford, California 94305 (United States); Hommelhoff, P. [Department of Physics, Friedrich Alexander University Erlangen-Nürnberg (FAU), Staudtstrasse 1, d-91058 Erlangen (Germany); Berggren, K.K. [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2016-05-15

    One of the astounding consequences of quantum mechanics is that it allows the detection of a target using an incident probe, with only a low probability of interaction of the probe and the target. This ‘quantum weirdness’ could be applied in the field of electron microscopy to generate images of beam-sensitive specimens with substantially reduced damage to the specimen. A reduction of beam-induced damage to specimens is especially of great importance if it can enable imaging of biological specimens with atomic resolution. Following a recent suggestion that interaction-free measurements are possible with electrons, we now analyze the difficulties of actually building an atomic resolution interaction-free electron microscope, or “quantum electron microscope”. A quantum electron microscope would require a number of unique components not found in conventional transmission electron microscopes. These components include a coherent electron beam-splitter or two-state-coupler, and a resonator structure to allow each electron to interrogate the specimen multiple times, thus supporting high success probabilities for interaction-free detection of the specimen. Different system designs are presented here, which are based on four different choices of two-state-couplers: a thin crystal, a grating mirror, a standing light wave and an electro-dynamical pseudopotential. Challenges for the detailed electron optical design are identified as future directions for development. While it is concluded that it should be possible to build an atomic resolution quantum electron microscope, we have also identified a number of hurdles to the development of such a microscope and further theoretical investigations that will be required to enable a complete interpretation of the images produced by such a microscope. - Highlights: • Quantum electron microscopy has the potential of reducing radiation damage. • QEM requires a fraction of the electron wave to pass through the sample

  9. An enzymatic biosensor based on three-dimensional ZnO nanotetrapods spatial net modified AlGaAs/GaAs high electron mobility transistors

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yu [State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology, Beijing 100083 (China); Bioengineering Program, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Zhang, Xiaohui; Yan, Xiaoqin; Liao, Qingliang; Wang, Zengze; Zhang, Yue, E-mail: yuezhang@ustb.edu.cn [State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology, Beijing 100083 (China)

    2014-11-24

    We designed and constructed three dimensional (3D) zinc oxide Nanotetrapods (T-ZnOs) modified AlGaAs/GaAs high electron mobility transistors (HEMTs) for enzymatic uric acid (UA) detection. The chemical vapor deposition synthesized T-ZnOs was distributed on the gate areas of HEMTs in order to immobilize uricase and improve the sensitivity of the HEMTs. Combining with the high efficiency of enzyme immobilization by T-ZnOs and high sensitivity from HEMT, the as-constructed uricase/T-ZnOs/HEMTs biosensor showed fast response towards UA at ∼1 s, wide linear range from 0.2 nM to 0.2 mM and the low detect limit at 0.2 nM. The results point out an avenue to design electronic device as miniaturized lab-on-chip device for high sensitive and specific in biomedical and clinical diagnosis applications.

  10. Highly efficient hybrid photovoltaics based on hyperbranched three-dimensional TiO2 electron transporting materials

    KAUST Repository

    Mahmood, Khalid; Swain, Bhabani Sankar; Amassian, Aram

    2015-01-01

    A 3D hyperbranched TiO2 electron transporting material is demonstrated, which exhibits superior carrier transport and lifetime, as well as excellent infiltration, leading to highly efficient mesostructured hybrid solar cells, such as lead-halide perovskites (15.5%) and dye-sensitized solar cells (11.2%).

  11. Highly efficient hybrid photovoltaics based on hyperbranched three-dimensional TiO2 electron transporting materials

    KAUST Repository

    Mahmood, Khalid

    2015-03-23

    A 3D hyperbranched TiO2 electron transporting material is demonstrated, which exhibits superior carrier transport and lifetime, as well as excellent infiltration, leading to highly efficient mesostructured hybrid solar cells, such as lead-halide perovskites (15.5%) and dye-sensitized solar cells (11.2%).

  12. Development of Scanning Ultrafast Electron Microscope Capability.

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Kimberlee Chiyoko [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Talin, Albert Alec [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Chandler, David W. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Michael, Joseph R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-11-01

    Modern semiconductor devices rely on the transport of minority charge carriers. Direct examination of minority carrier lifetimes in real devices with nanometer-scale features requires a measurement method with simultaneously high spatial and temporal resolutions. Achieving nanometer spatial resolutions at sub-nanosecond temporal resolution is possible with pump-probe methods that utilize electrons as probes. Recently, a stroboscopic scanning electron microscope was developed at Caltech, and used to study carrier transport across a Si p-n junction [ 1 , 2 , 3 ] . In this report, we detail our development of a prototype scanning ultrafast electron microscope system at Sandia National Laboratories based on the original Caltech design. This effort represents Sandia's first exploration into ultrafast electron microscopy.

  13. Three-Dimensional Flows

    CERN Document Server

    Araujo, Vitor; Viana, Marcelo

    2010-01-01

    In this book, the authors present the elements of a general theory for flows on three-dimensional compact boundaryless manifolds, encompassing flows with equilibria accumulated by regular orbits. The book aims to provide a global perspective of this theory and make it easier for the reader to digest the growing literature on this subject. This is not the first book on the subject of dynamical systems, but there are distinct aspects which together make this book unique. Firstly, this book treats mostly continuous time dynamical systems, instead of its discrete counterpart, exhaustively treated

  14. Study of Scanning Tunneling Microscope control electronics

    International Nuclear Information System (INIS)

    Oliva, A.J.; Pancarobo, M.; Denisenko, N.; Aguilar, M.; Rejon, V.; Pena, J.L.

    1994-01-01

    A theoretical study of Scanning Tunneling Microscope control electronics is made. The knowledge of its behaviour allows us to determine accurately the region where the unstable operation could effect the measurements, and also to set the optimal working parameters. Each feedback circuitry compound is discussed as well as their mutual interaction. Different working conditions analysis and results are presented. (Author) 12 refs

  15. The Titan Environmental Transmission Electron Microscope

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; Wagner, Jakob Birkedal; Jinschek, Jörg R.

    2009-01-01

    University of Denmark (DTU) provides a unique combination of techniques for studying materials of interest to the catalytic as well as the electronics and other communities [5]. DTU’s ETEM is based on the FEI Titan platform providing ultrahigh microscope stability pushing the imaging resolution into the sub...

  16. Exploring the environmental transmission electron microscope

    DEFF Research Database (Denmark)

    Wagner, Jakob B.; Cavalca, Filippo; Damsgaard, Christian D.

    2012-01-01

    of the opportunities that the environmental TEM (ETEM) offers when combined with other in situ techniques will be explored, directly in the microscope, by combining electron-based and photon-based techniques and phenomena. In addition, application of adjacent setups using sophisticated transfer methods...

  17. Design of hybrid two-dimensional and three-dimensional nanostructured arrays for electronic and sensing applications

    Science.gov (United States)

    Ko, Hyunhyub

    This dissertation presents the design of organic/inorganic hybrid 2D and 3D nanostructured arrays via controlled assembly of nanoscale building blocks. Two representative nanoscale building blocks such as carbon nanotubes (one-dimension) and metal nanoparticles (zero-dimension) are the core materials for the study of solution-based assembly of nanostructured arrays. The electrical, mechanical, and optical properties of the assembled nanostructure arrays have been investigated for future device applications. We successfully demonstrated the prospective use of assembled nanostructure arrays for electronic and sensing applications by designing flexible carbon nanotube nanomembranes as mechanical sensors, highly-oriented carbon nanotubes arrays for thin-film transistors, and gold nanoparticle arrays for SERS chemical sensors. In first section, we fabricated highly ordered carbon nanotube (CNT) arrays by tilted drop-casting or dip-coating of CNT solution on silicon substrates functionalized with micropatterned self-assembled monolayers. We further exploited the electronic performance of thin-film transistors based on highly-oriented, densely packed CNT micropatterns and showed that the carrier mobility is largely improved compared to randomly oriented CNTs. The prospective use of Raman-active CNTs for potential mechanical sensors has been investigated by studying the mechano-optical properties of flexible carbon nanotube nanomembranes, which contain freely-suspended carbon nanotube array encapsulated into ultrathin (optical waveguide properties of nano-canals. We demonstrated the ability of this SERS substrate for trace level sensing of nitroaromatic explosives by detecting down to 100 zeptogram (˜330 molecules) of DNT.

  18. Three-dimensional mesostructures as high-temperature growth templates, electronic cellular scaffolds, and self-propelled microrobots

    Science.gov (United States)

    Yan, Zheng; Han, Mengdi; Shi, Yan; Badea, Adina; Yang, Yiyuan; Kulkarni, Ashish; Hanson, Erik; Kandel, Mikhail E.; Wen, Xiewen; Zhang, Fan; Luo, Yiyue; Lin, Qing; Zhang, Hang; Guo, Xiaogang; Huang, Yuming; Nan, Kewang; Jia, Shuai; Oraham, Aaron W.; Mevis, Molly B.; Lim, Jaeman; Guo, Xuelin; Gao, Mingye; Ryu, Woomi; Yu, Ki Jun; Nicolau, Bruno G.; Petronico, Aaron; Rubakhin, Stanislav S.; Lou, Jun; Ajayan, Pulickel M.; Thornton, Katsuyo; Popescu, Gabriel; Fang, Daining; Sweedler, Jonathan V.; Braun, Paul V.; Zhang, Haixia; Nuzzo, Ralph G.; Huang, Yonggang; Zhang, Yihui; Rogers, John A.

    2017-11-01

    Recent work demonstrates that processes of stress release in prestrained elastomeric substrates can guide the assembly of sophisticated 3D micro/nanostructures in advanced materials. Reported application examples include soft electronic components, tunable electromagnetic and optical devices, vibrational metrology platforms, and other unusual technologies, each enabled by uniquely engineered 3D architectures. A significant disadvantage of these systems is that the elastomeric substrates, while essential to the assembly process, can impose significant engineering constraints in terms of operating temperatures and levels of dimensional stability; they also prevent the realization of 3D structures in freestanding forms. Here, we introduce concepts in interfacial photopolymerization, nonlinear mechanics, and physical transfer that bypass these limitations. The results enable 3D mesostructures in fully or partially freestanding forms, with additional capabilities in integration onto nearly any class of substrate, from planar, hard inorganic materials to textured, soft biological tissues, all via mechanisms quantitatively described by theoretical modeling. Illustrations of these ideas include their use in 3D structures as frameworks for templated growth of organized lamellae from AgCl-KCl eutectics and of atomic layers of WSe2 from vapor-phase precursors, as open-architecture electronic scaffolds for formation of dorsal root ganglion (DRG) neural networks, and as catalyst supports for propulsive systems in 3D microswimmers with geometrically controlled dynamics. Taken together, these methodologies establish a set of enabling options in 3D micro/nanomanufacturing that lie outside of the scope of existing alternatives.

  19. Probing plasmons in three dimensions by combining complementary spectroscopies in a scanning transmission electron microscope

    International Nuclear Information System (INIS)

    Hachtel, J A; Haglund, R F; Pantelides, S T; Marvinney, C; Mayo, D; Mouti, A; Lupini, A R; Chisholm, M F; Mu, R; Pennycook, S J

    2016-01-01

    The nanoscale optical response of surface plasmons in three-dimensional metallic nanostructures plays an important role in many nanotechnology applications, where precise spatial and spectral characteristics of plasmonic elements control device performance. Electron energy loss spectroscopy (EELS) and cathodoluminescence (CL) within a scanning transmission electron microscope have proven to be valuable tools for studying plasmonics at the nanoscale. Each technique has been used separately, producing three-dimensional reconstructions through tomography, often aided by simulations for complete characterization. Here we demonstrate that the complementary nature of the two techniques, namely that EELS probes beam-induced electronic excitations while CL probes radiative decay, allows us to directly obtain a spatially- and spectrally-resolved picture of the plasmonic characteristics of nanostructures in three dimensions. The approach enables nanoparticle-by-nanoparticle plasmonic analysis in three dimensions to aid in the design of diverse nanoplasmonic applications. (paper)

  20. Three-dimensional high dose rate dosimetry of electron beams. A combined radiochromic film, EPR and calorimetric dosimetry

    International Nuclear Information System (INIS)

    Secerov, B.; Milosavljevic, B.H.; Bacic, G.; Belgrade Univ.

    2002-01-01

    Complete text of publication follows. Aim. To examine the suitability of radiochromic film (RCF) dosimeters in determining 3D dose distribution from a pulsed electron beam source by comparing their response with alanine EPR dosimetry and calorimetry. Experimental. A FWT-60 radiochromic films (Far West Technology Inc) were used while alanine films were home made. To obtain the dose vs. penetration depth relationship, a stack of 13 films separated by aluminium plates and/or alanine films was placed perpendicular to the electron beam (Febetron, 20 ns, 1.8 MeV, 10 12 Gy/s, dose range up to 100 kGy). RC films were calibrated using 60-Co source and Fricke dosimetry. The absorbance of irradiated films was measured using 2D microdensitometry. Calorimetry was performed with a homemade quasy-adiabatic aluminum calorimeter. Results and Discussion. Microdensitometry of films (5 x 5 cm) enabled the 3D mapping of the entire radiation field with in plane resolution of 0.12 mm. The total dose for each film was obtained by image segmentation to correct for the non-linear response of films. Integrated dose for the entire stack was in good agreement (within 5%) with total absorbed energy as determined with calorimetry. The dose distribution along the beam center was determined using alanine films (1 x 1 cm) and EPR spectroscopy, and again a good agreement with the dose determined by microdensitometry of the central portion of RC films. In conclusion, the results indicate that RC films can be used for determination of 3D dose distribution even at very high dose rates

  1. Ultra-Low-Power Smart Electronic Nose System Based on Three-Dimensional Tin Oxide Nanotube Arrays.

    Science.gov (United States)

    Chen, Jiaqi; Chen, Zhuo; Boussaid, Farid; Zhang, Daquan; Pan, Xiaofang; Zhao, Huijuan; Bermak, Amine; Tsui, Chi-Ying; Wang, Xinran; Fan, Zhiyong

    2018-06-04

    In this work, we present a high-performance smart electronic nose (E-nose) system consisting of a multiplexed tin oxide (SnO 2 ) nanotube sensor array, read-out circuit, wireless data transmission unit, mobile phone receiver, and data processing application (App). Using the designed nanotube sensor device structure in conjunction with multiple electrode materials, high-sensitivity gas detection and discrimination have been achieved at room temperature, enabling a 1000 times reduction of the sensor's power consumption as compared to a conventional device using thin film SnO 2 . The experimental results demonstrate that the developed E-nose can identify indoor target gases using a simple vector-matching gas recognition algorithm. In addition, the fabricated E-nose has achieved state-of-the-art sensitivity for H 2 and benzene detection at room temperature with metal oxide sensors. Such a smart E-nose system can address the imperative needs for distributed environmental monitoring in smart homes, smart buildings, and smart cities.

  2. Investigation of electronic band structure and charge transfer mechanism of oxidized three-dimensional graphene as metal-free anodes material for dye sensitized solar cell application

    Science.gov (United States)

    Loeblein, Manuela; Bruno, Annalisa; Loh, G. C.; Bolker, Asaf; Saguy, Cecile; Antila, Liisa; Tsang, Siu Hon; Teo, Edwin Hang Tong

    2017-10-01

    Dye-sensitized solar cells (DSSCs) offer an optimal trade-off between conversion-efficiency and low-cost fabrication. However, since all its electrodes need to fulfill stringent work-function requirements, its materials have remained unchanged since DSSC's first report early-90s. Here we describe a new material, oxidized-three-dimensional-graphene (o-3D-C), with a band gap of 0.2 eV and suitable electronic band-structure as alternative metal-free material for DSSCs-anodes. o-3D-C/dye-complex has a strong chemical bonding via carboxylic-group chemisorption with full saturation after 12 sec at capacity of ∼450 mg/g (600x faster and 7x higher than optimized metal surfaces). Furthermore, fluorescence quenching of life-time by 28-35% was measured demonstrating charge-transfer from dye to o-3D-C.

  3. Three-dimensional data assimilation and reanalysis of radiation belt electrons: Observations over two solar cycles, and operational forecasting.

    Science.gov (United States)

    Kellerman, A. C.; Shprits, Y.; Kondrashov, D. A.; Podladchikova, T.; Drozdov, A.; Subbotin, D.; Makarevich, R. A.; Donovan, E.; Nagai, T.

    2015-12-01

    Understanding of the dynamics in Earth's radiation belts is critical to accurate modeling and forecasting of space weather conditions, both which are important for design, and protection of our space-borne assets. In the current study, we utilize the Versatile Electron Radiation Belt (VERB) code, multi-spacecraft measurements, and a split-operator Kalman filter to recontructe the global state of the radiation belt system in the CRRES era and the current era. The reanalysis has revealed a never before seen 4-belt structure in the radiation belts during the March 1991 superstorm, and highlights several important aspects in regards to the the competition between the source, acceleration, loss, and transport of particles. In addition to the above, performing reanalysis in adiabatic coordinates relies on specification of the Earth's magnetic field, and associated observational, and model errors. We determine the observational errors for the Kalman filter directly from cross-spacecraft phase-space density (PSD) conjunctions, and obtain the error in VERB by comparison with reanalysis over a long time period. Specification of errors associated with several magnetic field models provides an important insight into the applicability of such models for radiation belt research. The comparison of CRRES area reanalysis with Van Allen Probe era reanalysis allows us to perform a global comparison of the dynamics of the radiation belts during different parts of the solar cycle and during different solar cycles. The data assimilative model is presently used to perform operational forecasts of the radiation belts (http://rbm.epss.ucla.edu/realtime-forecast/).

  4. Isotope analysis in the transmission electron microscope.

    Science.gov (United States)

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

    2016-10-10

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

  5. Science 101: How Does an Electron Microscope Work?

    Science.gov (United States)

    Robertson, Bill

    2013-01-01

    Contrary to popular opinion, electron microscopes are not used to look at electrons. They are used to look for structure in things that are too small to observe with an optical microscope, or to obtain images that are magnified much more than is obtainable with an optical microscope. To understand how electron microscopes work, it will help to go…

  6. Transmission Electron Microscope Measures Lattice Parameters

    Science.gov (United States)

    Pike, William T.

    1996-01-01

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

  7. Ponderomotive phase plate for transmission electron microscopes

    Science.gov (United States)

    Reed, Bryan W [Livermore, CA

    2012-07-10

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

  8. Three dimensional MEMS supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wei

    2011-10-15

    The overall objective of this research is to achieve compact supercapacitors with high capacitance, large power density, and long cycle life for using as micro power sources to drive low power devices and sensors. The main shortcoming of supercapacitors as a power source is that its energy density typically is about 1/10 of that of batteries. To achieve compact supercapacitors of large energy density, supercapacitors must be developed with high capacitance and power density which are mainly depended on the effective surface area of the electrodes of the supercapacitors. Many studies have been done to increase the effective surface area by modifying the electrode materials, however, much less investigations are focus on machining the electrodes. In my thesis work, micro- and nano-technologies are applied as technology approaches for machining the electrodes with three dimensional (3D) microstructures. More specific, Micro-electro-mechanical system (MEMS) fabrication process flow, which integrates the key process such as LIGA-like (German acronym for Lithographie, Galvanoformung, Abformung, which mean Lithography, Electroplating and Molding) technology or DRIE (deep reactive ion etching), has been developed to enable innovative designs of 3D MEMS supercapacitors which own the electrodes of significantly increased geometric area. Two types of 3D MEMS supercapcitors, based on LIGA-like and DRIE technology respectively, were designed and successfully created. The LIGA-like based 3D MEMS supercapacitor is with an interdigital 3D structure, and consists of silicon substrate, two electroplated nickel current collectors, two PPy (poly pyrrole) electrodes, and solid state electrolyte. The fabrication process flow developed includes the flowing key processes, SU-8 lithography, nickel electroplating, PPy polymerization and solid state electrolyte coating. Electrochemical tests showed that the single electrode of the supercapacitor has the specific capacitance of 0.058 F cm-2

  9. Atmospheric scanning electron microscope for correlative microscopy.

    Science.gov (United States)

    Morrison, Ian E G; Dennison, Clare L; Nishiyama, Hidetoshi; Suga, Mitsuo; Sato, Chikara; Yarwood, Andrew; O'Toole, Peter J

    2012-01-01

    The JEOL ClairScope is the first truly correlative scanning electron and optical microscope. An inverted scanning electron microscope (SEM) column allows electron images of wet samples to be obtained in ambient conditions in a biological culture dish, via a silicon nitride film window in the base. A standard inverted optical microscope positioned above the dish holder can be used to take reflected light and epifluorescence images of the same sample, under atmospheric conditions that permit biochemical modifications. For SEM, the open dish allows successive staining operations to be performed without moving the holder. The standard optical color camera used for fluorescence imaging can be exchanged for a high-sensitivity monochrome camera to detect low-intensity fluorescence signals, and also cathodoluminescence emission from nanophosphor particles. If these particles are applied to the sample at a suitable density, they can greatly assist the task of perfecting the correlation between the optical and electron images. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. Digital management of an electron microscope unit

    International Nuclear Information System (INIS)

    Elea, N.; Dickson, M.; Munroe, P.

    2002-01-01

    Full text: Electron microscope units, especially those such as ours, which operate as a central infrastructural facility are increasingly asked to provide more service, over more instruments with decreasing, or limited, financial resources. We believe that staff time is best used performing electron microscopy, assisting users and maintaining instrumentation rather than in the pursuit of red tape. One solution to this problem has been the creation of a control system which performs all routine acts of data management, such as the archiving and accessing of digital data, providing access to bookings, and most importantly in the era of user pays services, logging time and billing users. The system we have created, developed and expanded allows the users themselves to access our server through any web-browser and make their own bookings or access and manipulate their data. Users themselves must log on to a microscope through swipecard readers before it can be used and log-off after use. Their time is logged precisely and an exquisitely fair user pays systems can be operated by transferring logged usage time to spreadsheets to calculate charges. Furthermore, this system acts as a method of user authentication and can be used to bar incompetent or unauthorised users. The system has recently been upgraded to increase its utility to include sensors that monitor the electron microscope operating environment, such as magnetic field, room temperature, water flow etc, so that if these parameters depart significantly from optimum levels electron microscope unit staff may be alerted. In this presentation the structure of our system will be described and the advantages and disadvantages of such a system will be discussed. Copyright (2002) Australian Society for Electron Microscopy Inc

  11. Electron microscopic radioautography of the cell

    International Nuclear Information System (INIS)

    Sarkisov, D.S.; Pal'tsyn, A.A.; Vtyurin, B.V.

    1980-01-01

    This monograph is the first one in the world literature that gives th generalised experience in application of the up-to-date method of structural and functional analysis, i.e. of electron-microscopic autography to study the dynamics of intracellular processes under normal conditions as well as under some pathogenic effects. Given herein are the data on synthesis of DNA and RNA in various structures of the nucleus, particularly in nucleoli, the regularities of the synthesis processes in the organellae of the same name are discussed; illustrated are the possibilities of structure analysis of biosynthesis intensity variations in the nucleus and cytoplasma in cells of liver miocardium, granulation tissue at different stages of morphological process; the results of electron-microscopic radioautography application in study of clinical biopsy material are given and the data obtained are discussed in the light of general pathology problems

  12. Electron spin resonance scanning tunneling microscope

    International Nuclear Information System (INIS)

    Guo Yang; Li Jianmei; Lu Xinghua

    2015-01-01

    It is highly expected that the future informatics will be based on the spins of individual electrons. The development of elementary information unit will eventually leads to novel single-molecule or single-atom devices based on electron spins; the quantum computer in the future can be constructed with single electron spins as the basic quantum bits. However, it is still a great challenge in detection and manipulation of a single electron spin, as well as its coherence and entanglement. As an ideal experimental tool for such tasks, the development of electron spin resonance scanning tunneling microscope (ESR-STM) has attracted great attention for decades. This paper briefly introduces the basic concept of ESR-STM. The development history of this instrument and recent progresses are reviewed. The underlying mechanism is explored and summarized. The challenges and possible solutions are discussed. Finally, the prospect of future direction and applications are presented. (authors)

  13. Three-Dimensional Packing Structure and Electronic Properties of Biaxially Oriented Poly(2,5-bis(3-alkylthiophene-2-yl)thieno[3,2- b ]thiophene) Films

    KAUST Repository

    Cho, Eunkyung

    2012-04-11

    We use a systematic approach that combines experimental X-ray diffraction (XRD) and computational modeling based on molecular mechanics and two-dimensional XRD simulations to develop a detailed model of the molecular-scale packing structure of poly(2,5-bis (3-tetradecylthiophene-2-yl) thieno[3,2-b]thiophene) (PBTTT-C 14) films. Both uniaxially and biaxially aligned films are used in this comparison and lead to an improved understanding of the molecular-scale orientation and crystal structure. We then examine how individual polymer components (i.e., conjugated backbone and alkyl side chains) contribute to the complete diffraction pattern, and how modest changes to a particular component orientation (e.g., backbone or side-chain tilt) influence the diffraction pattern. The effects on the polymer crystal structure of varying the alkyl side-chain length from C 12 to C 14 and C 16 are also studied. The accurate determination of the three-dimensional polymer structure allows us to examine the PBTTT electronic band structure and intermolecular electronic couplings (transfer integrals) as a function of alkyl side-chain length. This combination of theoretical and experimental techniques proves to be an important tool to help establish the relationship between the structural and electronic properties of polymer thin films. © 2012 American Chemical Society.

  14. Dose modeling of noninvasive image-guided breast brachytherapy in comparison to electron beam boost and three-dimensional conformal accelerated partial breast irradiation.

    Science.gov (United States)

    Sioshansi, Shirin; Rivard, Mark J; Hiatt, Jessica R; Hurley, Amanda A; Lee, Yoojin; Wazer, David E

    2011-06-01

    To perform dose modeling of a noninvasive image-guided breast brachytherapy (NIIGBB) for comparison to electrons and 3DCRT. The novel technology used in this study is a mammography-based, noninvasive breast brachytherapy system whereby the treatment applicators are centered on the planning target volume (PTV) to direct (192)Ir emissions along orthogonal axes. To date, three-dimensional dose modeling of NIIGBB has not been possible because of the limitations of conventional treatment planning systems (TPS) to model variable tissue deformation associated with breast compression. In this study, the TPS was adapted such that the NIIGBB dose distributions were modeled as a virtual point source. This dose calculation technique was applied to CT data from 8 patients imaged with the breast compressed between parallel plates in the cranial-caudal and medial-lateral axes. A dose-volume comparison was performed to simulated electron boost and 3DCRT APBI. The NIIGBB PTV was significantly reduced as compared with both electrons and 3DCRT. Electron boost plans had a lower D(min) than the NIIGBB technique but higher V(100), D(90), and D(50). With regard to PTV coverage for APBI, the only significant differences were minimally higher D(90), D(100), V(80), and V(90), with 3DCRT and D(max) with NIIGBB. The NIIGBB technique, as compared with electrons and 3D-CRT, achieved a lower maximum dose to skin (60% and 10%, respectively) and chest wall/lung (70-90%). NIIGBB achieves a PTV that is smaller than electron beam and 3DCRT techniques. This results in significant normal tissue sparing while maintaining dosimetric benchmarks to the target tissue. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. French contributions to electron microscopic radioautography

    International Nuclear Information System (INIS)

    Droz, B.

    1994-01-01

    The radio autographic contributions carried out by electron microscopists took a part to improve the methodology and to extend applications to major biological problems. As underlined by CP Leblonc radioautography has clarified the importance of renewing systems; one may truly say that radioautography has introduced the time dimension in histology. The sites of biosynthesis of different substances have been located on the sub cellar scale, and it is now possible to analyse the molecular migrations within cells. The development of in situ hybridization and of receptors binding sites at the ultrastructural level has enlarged the application field of electron microscope radioautography. 64 refs., 2 figs

  16. Three-dimensional positioning with optofluidic microscope

    DEFF Research Database (Denmark)

    Vig, Asger Laurberg; Marie, Rodolphe; Jensen, Eric

    2010-01-01

    in the plane perpendicular to the flow direction and the velocity along the flow direction of separated fluorescent labeled polystyrene microspheres with diameters of 1 μm, 2.1 μm, 3 μm and 4 μm is measured using the OFM readout. These results are bench marked against those obtained with a PFF device using...

  17. Three dimensional energy profile:

    International Nuclear Information System (INIS)

    Kowsari, Reza; Zerriffi, Hisham

    2011-01-01

    The provision of adequate, reliable, and affordable energy has been considered as a cornerstone of development. More than one-third of the world's population has a very limited access to modern energy services and suffers from its various negative consequences. Researchers have been exploring various dimensions of household energy use in order to design strategies to provide secure access to modern energy services. However, despite more than three decades of effort, our understanding of household energy use patterns is very limited, particularly in the context of rural regions of the developing world. Through this paper, the past and the current trends in the field of energy analysis are investigated. The literature on rural energy and energy transition in developing world has been explored and the factors affecting households' decisions on energy use are listed. The and the factors affecting households' decisions on energy use are listed. The gaps identified in the literature on rural household energy analysis provide a basis for developing an alternative model that can create a more realistic view of household energy use. The three dimensional energy profile is presented as a new conceptual model for assessment of household energy use. This framework acts as a basis for building new theoretical and empirical models of rural household energy use. - Highlights: ► Reviews literature on household energy, energy transitions and decision-making in developing countries. ► Identifies gaps in rural household energy analysis and develops a new conceptual framework. ► The 3-d energy profile provides a holistic view of household energy system characteristics. ► Illustrates the use of the framework for understanding household energy transitions.

  18. Three-dimensional echocardiography

    International Nuclear Information System (INIS)

    Buck, Thomas

    2011-01-01

    Presents tips and tricks for beginners and experts Provides educational material for 3D training courses Features comprehensively illustrated cases Includes an accompanying DVD with video clips of all sample cases Three-dimensional echocardiography is the most recent fundamental advancement in echocardiography. Since real-time 3D echocardiography became commercially available in 2002, it has rapidly been accepted in echo labs worldwide. This book covers all clinically relevant aspects of this fascinating new technology, including a comprehensive explanation of its basic principles, practical aspects of clinical application, and detailed descriptions of specific uses in the broad spectrum of clinically important heart disease. The book was written by a group of well-recognized international experts in the field, who have not only been involved in the scientific and clinical evolution of 3D echocardiography since its inception but are also intensively involved in expert training courses. As a result, the clear focus of this book is on the practical application of 3D echocardiography in daily clinical routine with tips and tricks for both beginners and experts, accompanied by more than 150 case examples comprehensively illustrated in more than 800 images and more than 500 videos provided on a DVD. In addition to an in-depth review of the most recent literature on real-time 3D echocardiography, this book represents an invaluable reference work for beginners and expert users of 3D echocardiography. - Tips and tricks for beginners and experts - Educational material for 3D training courses - Comprehensively illustrated cases - DVD with video clips of all sample cases.

  19. Three-dimensional transient cooling simulations of a portable electronic device using PCM (phase change materials) in multi-fin heat sink

    International Nuclear Information System (INIS)

    Wang, Yi-Hsien; Yang, Yue-Tzu

    2011-01-01

    Transient three-dimensional heat transfer numerical simulations were conducted to investigate a hybrid PCM (phase change materials) based multi-fin heat sink. Numerical computation was conducted with different amounts of fins (0 fin, 3 fins and 6 fins), various heating power level (2 W, 3 W and 4 W), different orientation tests (vertical/horizontal/slanted), and charge and discharge modes. Calculating time step (0.03 s, 0.05 s, and 0.07 s) size was discussed for transient accuracy as well. The theoretical model developed is validated by comparing numerical predictions with the available experimental data in the literature. The results showed that the transient surface temperatures are predicted with a maximum discrepancy within 10.2%. The operation temperature can be controlled well by the attendance of phase change material and the longer melting time can be conducted by using a multi-fin hybrid heat sink respectively. -- Highlights: → Electronic device cooling use phase change materials. → N-eicosane is adapted as phase change materials. → Present surface transient temperatures prediction error is within 10.2%. → Hybrid PCM-heat sink system provides stable operation temperature. → Orientation effects show independent on the phase change performance.

  20. Interplay between cellular activity and three-dimensional scaffold-cell constructs with different foam structure processed by electron beam melting.

    Science.gov (United States)

    Nune, Krishna C; Misra, R Devesh K; Gaytan, Sara M; Murr, Lawrence E

    2015-05-01

    The cellular activity, biological response, and consequent integration of scaffold-cell construct in the physiological system are governed by the ability of cells to adhere, proliferate, and biomineralize. In this regard, we combine cellular biology and materials science and engineering to fundamentally elucidate the interplay between cellular activity and interconnected three-dimensional foamed architecture obtained by a novel process of electron beam melting and computational tools. Furthermore, the organization of key proteins, notably, actin, vinclulin, and fibronectin, involved in cellular activity and biological functions and relationship with the structure was explored. The interconnected foamed structure with ligaments was favorable to cellular activity that includes cell attachment, proliferation, and differentiation. The primary rationale for favorable modulation of cellular functions is that the foamed structure provided a channel for migration and communication between cells leading to highly mineralized extracellular matrix (ECM) by the differentiating osteoblasts. The filopodial interaction amongst cells on the ligaments was a governing factor in the secretion of ECM, with consequent influence on maturation and mineralization. © 2014 Wiley Periodicals, Inc.

  1. Efficient estimation of three-dimensional covariance and its application in the analysis of heterogeneous samples in cryo-electron microscopy.

    Science.gov (United States)

    Liao, Hstau Y; Hashem, Yaser; Frank, Joachim

    2015-06-02

    Single-particle cryogenic electron microscopy (cryo-EM) is a powerful tool for the study of macromolecular structures at high resolution. Classification allows multiple structural states to be extracted and reconstructed from the same sample. One classification approach is via the covariance matrix, which captures the correlation between every pair of voxels. Earlier approaches employ computing-intensive resampling and estimate only the eigenvectors of the matrix, which are then used in a separate fast classification step. We propose an iterative scheme to explicitly estimate the covariance matrix in its entirety. In our approach, the flexibility in choosing the solution domain allows us to examine a part of the molecule in greater detail. Three-dimensional covariance maps obtained in this way from experimental data (cryo-EM images of the eukaryotic pre-initiation complex) prove to be in excellent agreement with conclusions derived by using traditional approaches, revealing in addition the interdependencies of ligand bindings and structural changes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Indigenous development of scanning electron microscope

    International Nuclear Information System (INIS)

    Ambastha, K.P.; Chaudhari, Y.V.; Pal, Suvadip; Tikaria, Amit; Pious, Lizy; Dubey, B.P.; Chadda, V.K.

    2009-01-01

    Scanning electron microscope (SEM) is a precision instrument and plays very important role in scientific studies. Bhabha Atomic Research Centre has taken up the job of development of SEM indigenously. Standard and commercially available components like computer, high voltage power supply, detectors etc. shall be procured from market. Focusing and scanning coils, vacuum chamber, specimen stage, control hardware and software etc. shall be developed at BARC with the help of Indian industry. Procurement, design and fabrication of various parts of SEM are in progress. (author)

  3. Electron microscope studies on nuclear track filters

    International Nuclear Information System (INIS)

    Roell, I.; Siegmon, W.

    1982-01-01

    Nuclear track filters became more and more important in various fields of application. The filtration process can be described by a set of suitable parameters. For some applications it may be necessary to know the structure of the surface and the pores themselves. In most cases the etching process yields surfaces and pore geometries that are quite different from ideal planes and cylinders. In the presented work the production of different filter types will be described. The resulting surfaces and pore structures have been investigated by means of a scanning electron microscope. (author)

  4. Multiparallel Three-Dimensional Optical Microscopy

    Science.gov (United States)

    Nguyen, Lam K.; Price, Jeffrey H.; Kellner, Albert L.; Bravo-Zanoquera, Miguel

    2010-01-01

    Multiparallel three-dimensional optical microscopy is a method of forming an approximate three-dimensional image of a microscope sample as a collection of images from different depths through the sample. The imaging apparatus includes a single microscope plus an assembly of beam splitters and mirrors that divide the output of the microscope into multiple channels. An imaging array of photodetectors in each channel is located at a different distance along the optical path from the microscope, corresponding to a focal plane at a different depth within the sample. The optical path leading to each photodetector array also includes lenses to compensate for the variation of magnification with distance so that the images ultimately formed on all the photodetector arrays are of the same magnification. The use of optical components common to multiple channels in a simple geometry makes it possible to obtain high light-transmission efficiency with an optically and mechanically simple assembly. In addition, because images can be read out simultaneously from all the photodetector arrays, the apparatus can support three-dimensional imaging at a high scanning rate.

  5. Three-dimensional ICT reconstruction

    International Nuclear Information System (INIS)

    Zhang Aidong; Li Ju; Chen Fa; Sun Lingxia

    2005-01-01

    The three-dimensional ICT reconstruction method is the hot topic of recent ICT technology research. In the context, qualified visual three-dimensional ICT pictures are achieved through multi-piece two-dimensional images accumulation by, combining with thresholding method and linear interpolation. Different direction and different position images of the reconstructed pictures are got by rotation and interception respectively. The convenient and quick method is significantly instructive to more complicated three-dimensional reconstruction of ICT images. (authors)

  6. Three-dimensional ICT reconstruction

    International Nuclear Information System (INIS)

    Zhang Aidong; Li Ju; Chen Fa; Sun Lingxia

    2004-01-01

    The three-dimensional ICT reconstruction method is the hot topic of recent ICT technology research. In the context qualified visual three-dimensional ICT pictures are achieved through multi-piece two-dimensional images accumulation by order, combining with thresholding method and linear interpolation. Different direction and different position images of the reconstructed pictures are got by rotation and interception respectively. The convenient and quick method is significantly instructive to more complicated three-dimensional reconstruction of ICT images. (authors)

  7. Electron microscope autoradiography of isolated DNA molecules

    International Nuclear Information System (INIS)

    Delain, Etienne; Bouteille, Michel

    1980-01-01

    Autoradiographs of 3 H-thymidine-labelled DNA molecules were observed with an electron microscope. After ten months of exposure significant labelling was obtained with tritiated T7 DNA molecules which had a specific activity of 630,000 cpm/μg. Although isolated DNA molecules were not stretched out to such an extent that they could be rigorously compared to straight 'hot lines', the resolution was estimated and found to be similar to that obtained by autoradiography on thin plastic sections. The H.D. value was of the order of 1600A. From the known specific activity of the macromolecules, it was possible to compare the expected number of disintegrations from the samples to the number of grains obtained on the autoradiograms. This enabled us to calculate 1/ The absolute autoradiographic efficiency and 2/ The per cent ratio of thymidine residues labelled with tritium. These results throw some light on the resolution and sensitivity of electron microscope autoradiography of shadowed isolated macromolecules as compared to thin plastic sections

  8. Cathodoluminescence in the scanning transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-05-15

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

  9. Helium leak testing of scanning electron microscope

    International Nuclear Information System (INIS)

    Ahmad, Anis; Tripathi, S.K.; Mukherjee, D.

    2015-01-01

    Scanning Electron Microscope (SEM) is a specialized electron-optical device which is used for imaging of miniscule features on topography of material specimens. Conventional SEMs used finely focused high energy (about 30 KeV) electron beam probes of diameter of about 10nm for imaging of solid conducting specimens. Vacuum of the order of 10"-"5 Torr is prerequisite for conventional Tungsten filament type SEMs. One such SEM was received from one of our laboratory in BARC with a major leak owing to persisting poor vacuum condition despite continuous pumping for several hours. He-Leak Detection of the SEM was carried out at AFD using vacuum spray Technique and various potential leak joints numbering more than fifty were helium leak tested. The major leak was detected in the TMP damper bellow. The part was later replaced and the repeat helium leak testing of the system was carried out using vacuum spray technique. The vacuum in SEM is achieved is better than 10"-"5 torr and system is now working satisfactorily. (author)

  10. Polycrystal model of the mechanical behavior of a Mo–TiC30vol.% metal–ceramic composite using a three-dimensional microstructure map obtained by dual beam focused ion beam scanning electron microscopy

    International Nuclear Information System (INIS)

    Cédat, D.; Fandeur, O.; Rey, C.; Raabe, D.

    2012-01-01

    The mechanical behavior of a Mo–TiC 30vol.% ceramic–metal composite was investigated over a wide temperature range (25–700 °C). High-energy X-ray tomography was used to reveal percolation of the hard titanium carbide phase through the composite. Using a polycrystal approach for a two-phase material, finite-element simulations were performed on a real three-dimensional (3-D) aggregate of the material. The 3-D microstructure, used as the starting configuration for the predictions, was obtained by serial sectioning in a dual beam focused ion beam scanning electron microscope coupled to an electron backscattered diffraction system. The 3-D aggregate consists of a molybdenum matrix and a percolating TiC skeleton. As for most body-centered cubic (bcc) metals, the molybdenum matrix phase is characterized by a change in plasticity mechanism with temperature. We used a polycrystal model for bcc materials which was extended to two phases (TiC and Mo). The model parameters of the matrix were determined from experiments on pure molydenum. For all temperatures investigated the TiC particles were considered to be brittle. Gradual damage to the TiC particles was treated, based on an accumulative failure law that is approximated by evolution of the apparent particle elastic stiffness. The model enabled us to determine the evolution of the local mechanical fields with deformation and temperature. We showed that a 3-D aggregate representing the actual microstructure of the composite is required to understand the local and global mechanical properties of the composite studied.

  11. Comparative study of image contrast in scanning electron microscope and helium ion microscope.

    Science.gov (United States)

    O'Connell, R; Chen, Y; Zhang, H; Zhou, Y; Fox, D; Maguire, P; Wang, J J; Rodenburg, C

    2017-12-01

    Images of Ga + -implanted amorphous silicon layers in a 110 n-type silicon substrate have been collected by a range of detectors in a scanning electron microscope and a helium ion microscope. The effects of the implantation dose and imaging parameters (beam energy, dwell time, etc.) on the image contrast were investigated. We demonstrate a similar relationship for both the helium ion microscope Everhart-Thornley and scanning electron microscope Inlens detectors between the contrast of the images and the Ga + density and imaging parameters. These results also show that dynamic charging effects have a significant impact on the quantification of the helium ion microscope and scanning electron microscope contrast. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  12. Investigation of voltages and electric fields in silicon semi 3D radiation detectors using Silvaco/ATLAS simulation tool and a scanning electron microscope

    CERN Document Server

    Palviainen, T; Tuuva, T; Eranen, S; Härkönen, J; Luukka, P; Tuovinen, E

    2006-01-01

    The structure of silicon semi three-dimensional radiation detector is simulated on purpose to find out its electrical characteristics such as the depletion voltage and electric field. Two-dimensional simulation results are compared to voltage and electric field measurements done by a scanning electron microscope.

  13. Nitrogen implantation with a scanning electron microscope.

    Science.gov (United States)

    Becker, S; Raatz, N; Jankuhn, St; John, R; Meijer, J

    2018-01-08

    Established techniques for ion implantation rely on technically advanced and costly machines like particle accelerators that only few research groups possess. We report here about a new and surprisingly simple ion implantation method that is based upon a widespread laboratory instrument: The scanning electron microscope. We show that it can be utilized to ionize atoms and molecules from the restgas by collisions with electrons of the beam and subsequently accelerate and implant them into an insulating sample by the effect of a potential building up at the sample surface. Our method is demonstrated by the implantation of nitrogen ions into diamond and their subsequent conversion to nitrogen vacancy centres which can be easily measured by fluorescence confocal microscopy. To provide evidence that the observed centres are truly generated in the way we describe, we supplied a 98% isotopically enriched 15 N gas to the chamber, whose natural abundance is very low. By employing the method of optically detected magnetic resonance, we were thus able to verify that the investigated centres are actually created from the 15 N isotopes. We also show that this method is compatible with lithography techniques using e-beam resist, as demonstrated by the implantation of lines using PMMA.

  14. A sub-cm micromachined electron microscope

    Science.gov (United States)

    Feinerman, A. D.; Crewe, D. A.; Perng, D. C.; Shoaf, S. E.; Crewe, A. V.

    1993-01-01

    A new approach for fabricating macroscopic (approximately 10x10x10 mm(exp 3)) structures with micron accuracy has been developed. This approach combines the precision of semiconductor processing and fiber optic technologies. A (100) silicon wafer is anisotropically etched to create four orthogonal v-grooves and an aperture on each 10x12 mm die. Precision 308 micron optical fibers are sandwiched between the die to align the v-grooves. The fiber is then anodically bonded to the die above and below it. This procedure is repeated to create thick structures and a stack of 5 or 6 die will be used to create a miniature scanning electron microscope (MSEM). Two die in the structure will have a segmented electrode to deflect the beam and correct for astigmatism. The entire structure is UHV compatible. The performance of an SEM improves as its length is reduced and a sub-cm 2 keV MSEM with a field emission source should have approximately 1 nm resolution. A low voltage high resolution MSEM would be useful for the examination of biological specimens and semiconductors with a minimum of damage. The first MSEM will be tested with existing 6 micron thermionic sources. In the future a micromachined field emission source will be used. The stacking technology presented in this paper can produce an array of MSEMs 1 to 30 mm in length with a 1 mm or larger period. A key question being addressed by this research is the optimum size for a low voltage MSEM which will be determined by the required spatial resolution, field of view, and working distance.

  15. Three-dimensional biomedical imaging

    International Nuclear Information System (INIS)

    Robb, R.A.

    1985-01-01

    Scientists in biomedical imaging provide researchers, physicians, and academicians with an understanding of the fundamental theories and practical applications of three-dimensional biomedical imaging methodologies. Succinct descriptions of each imaging modality are supported by numerous diagrams and illustrations which clarify important concepts and demonstrate system performance in a variety of applications. Comparison of the different functional attributes, relative advantages and limitations, complementary capabilities, and future directions of three-dimensional biomedical imaging modalities are given. Volume 1: Introductions to Three-Dimensional Biomedical Imaging Photoelectronic-Digital Imaging for Diagnostic Radiology. X-Ray Computed Tomography - Basic Principles. X-Ray Computed Tomography - Implementation and Applications. X-Ray Computed Tomography: Advanced Systems and Applications in Biomedical Research and Diagnosis. Volume II: Single Photon Emission Computed Tomography. Position Emission Tomography (PET). Computerized Ultrasound Tomography. Fundamentals of NMR Imaging. Display of Multi-Dimensional Biomedical Image Information. Summary and Prognostications

  16. Three-dimensional deformation of orthodontic brackets

    Science.gov (United States)

    Melenka, Garrett W; Nobes, David S; Major, Paul W

    2013-01-01

    Braces are used by orthodontists to correct the misalignment of teeth in the mouth. Archwire rotation is a particular procedure used to correct tooth inclination. Wire rotation can result in deformation to the orthodontic brackets, and an orthodontic torque simulator has been designed to examine this wire–bracket interaction. An optical technique has been employed to measure the deformation due to size and geometric constraints of the orthodontic brackets. Images of orthodontic brackets are collected using a stereo microscope and two charge-coupled device cameras, and deformation of orthodontic brackets is measured using a three-dimensional digital image correlation technique. The three-dimensional deformation of orthodontic brackets will be evaluated. The repeatability of the three-dimensional digital image correlation measurement method was evaluated by performing 30 archwire rotation tests using the same bracket and archwire. Finally, five Damon 3MX and five In-Ovation R self-ligating brackets will be compared using this technique to demonstrate the effect of archwire rotation on bracket design. PMID:23762201

  17. Three-dimensional deformation of orthodontic brackets.

    Science.gov (United States)

    Melenka, Garrett W; Nobes, David S; Major, Paul W; Carey, Jason P

    2013-01-01

    Braces are used by orthodontists to correct the misalignment of teeth in the mouth. Archwire rotation is a particular procedure used to correct tooth inclination. Wire rotation can result in deformation to the orthodontic brackets, and an orthodontic torque simulator has been designed to examine this wire-bracket interaction. An optical technique has been employed to measure the deformation due to size and geometric constraints of the orthodontic brackets. Images of orthodontic brackets are collected using a stereo microscope and two charge-coupled device cameras, and deformation of orthodontic brackets is measured using a three-dimensional digital image correlation technique. The three-dimensional deformation of orthodontic brackets will be evaluated. The repeatability of the three-dimensional digital image correlation measurement method was evaluated by performing 30 archwire rotation tests using the same bracket and archwire. Finally, five Damon 3MX and five In-Ovation R self-ligating brackets will be compared using this technique to demonstrate the effect of archwire rotation on bracket design.

  18. Three-dimensional structure of Au nanoparticles supported on amorphous silica and carbon substrates

    International Nuclear Information System (INIS)

    Bruma, A; Li, Z Y

    2012-01-01

    Scanning Transmission Electron Microscope (STEM) has been employed to study the three-dimensional structure of gold (Au) nanoparticles deposited by means of thermal evaporation in high vacuum on amorphous silica (a-SiO 2 ) and amorphous carbon (a-C) supports. By performing quantitative analysis on the evolution of the high angle annular dark field (HAADF) images, we studied the influence of the nature and the temperature of support on the growth mode of gold nanoparticles.

  19. Electronic structure, Dirac points and Fermi arc surface states in three-dimensional Dirac semimetal Na3Bi from angle-resolved photoemission spectroscopy

    International Nuclear Information System (INIS)

    Liang Aiji; Chen Chaoyu; Wang Zhijun; Shi Youguo; Feng Ya; Yi Hemian; Xie Zhuojin; He Shaolong; He Junfeng; Peng Yingying; Liu Yan; Liu Defa; Hu Cheng; Zhao Lin; Liu Guodong; Dong Xiaoli; Zhang Jun; Nakatake, M; Iwasawa, H; Shimada, K

    2016-01-01

    The three-dimensional (3D) Dirac semimetals have linearly dispersive 3D Dirac nodes where the conduction band and valence band are connected. They have isolated 3D Dirac nodes in the whole Brillouin zone and can be viewed as a 3D counterpart of graphene. Recent theoretical calculations and experimental results indicate that the 3D Dirac semimetal state can be realized in a simple stoichiometric compound A 3 Bi ( A = Na, K, Rb). Here we report comprehensive high-resolution angle-resolved photoemission (ARPES) measurements on the two cleaved surfaces, (001) and (100), of Na 3 Bi. On the (001) surface, by comparison with theoretical calculations, we provide a proper assignment of the observed bands, and in particular, pinpoint the band that is responsible for the formation of the three-dimensional Dirac cones. We observe clear evidence of 3D Dirac cones in the three-dimensional momentum space by directly measuring on the k x – k y plane and by varying the photon energy to get access to different out-of-plane k z s. In addition, we reveal new features around the Brillouin zone corners that may be related with surface reconstruction. On the (100) surface, our ARPES measurements over a large momentum space raise an issue on the selection of the basic Brillouin zone in the (100) plane. We directly observe two isolated 3D Dirac nodes on the (100) surface. We observe the signature of the Fermi-arc surface states connecting the two 3D Dirac nodes that extend to a binding energy of ∼150 meV before merging into the bulk band. Our observations constitute strong evidence on the existence of the Dirac semimetal state in Na 3 Bi that are consistent with previous theoretical and experimental work. In addition, our results provide new information to clarify on the nature of the band that forms the 3D Dirac cones, on the possible formation of surface reconstruction of the (001) surface, and on the issue of basic Brillouin zone selection for the (100) surface. (rapid communication)

  20. An electron microscope for the aberration-corrected era

    Energy Technology Data Exchange (ETDEWEB)

    Krivanek, O.L. [Nion Co., 1102 8th Street, Kirkland, WA 98033 (United States)], E-mail: krivanek.ondrej@gmail.com; Corbin, G.J.; Dellby, N.; Elston, B.F.; Keyse, R.J.; Murfitt, M.F.; Own, C.S.; Szilagyi, Z.S.; Woodruff, J.W. [Nion Co., 1102 8th Street, Kirkland, WA 98033 (United States)

    2008-02-15

    Improved resolution made possible by aberration correction has greatly increased the demands on the performance of all parts of high-end electron microscopes. In order to meet these demands, we have designed and built an entirely new scanning transmission electron microscope (STEM). The microscope includes a flexible illumination system that allows the properties of its probe to be changed on-the-fly, a third-generation aberration corrector which corrects all geometric aberrations up to fifth order, an ultra-responsive yet stable five-axis sample stage, and a flexible configuration of optimized detectors. The microscope features many innovations, such as a modular column assembled from building blocks that can be stacked in almost any order, in situ storage and cleaning facilities for up to five samples, computer-controlled loading of samples into the column, and self-diagnosing electronics. The microscope construction is described, and examples of its capabilities are shown.

  1. An electron microscope for the aberration-corrected era

    International Nuclear Information System (INIS)

    Krivanek, O.L.; Corbin, G.J.; Dellby, N.; Elston, B.F.; Keyse, R.J.; Murfitt, M.F.; Own, C.S.; Szilagyi, Z.S.; Woodruff, J.W.

    2008-01-01

    Improved resolution made possible by aberration correction has greatly increased the demands on the performance of all parts of high-end electron microscopes. In order to meet these demands, we have designed and built an entirely new scanning transmission electron microscope (STEM). The microscope includes a flexible illumination system that allows the properties of its probe to be changed on-the-fly, a third-generation aberration corrector which corrects all geometric aberrations up to fifth order, an ultra-responsive yet stable five-axis sample stage, and a flexible configuration of optimized detectors. The microscope features many innovations, such as a modular column assembled from building blocks that can be stacked in almost any order, in situ storage and cleaning facilities for up to five samples, computer-controlled loading of samples into the column, and self-diagnosing electronics. The microscope construction is described, and examples of its capabilities are shown

  2. Three-dimensional Imaging, Visualization, and Display

    CERN Document Server

    Javidi, Bahram; Son, Jung-Young

    2009-01-01

    Three-Dimensional Imaging, Visualization, and Display describes recent developments, as well as the prospects and challenges facing 3D imaging, visualization, and display systems and devices. With the rapid advances in electronics, hardware, and software, 3D imaging techniques can now be implemented with commercially available components and can be used for many applications. This volume discusses the state-of-the-art in 3D display and visualization technologies, including binocular, multi-view, holographic, and image reproduction and capture techniques. It also covers 3D optical systems, 3D display instruments, 3D imaging applications, and details several attractive methods for producing 3D moving pictures. This book integrates the background material with new advances and applications in the field, and the available online supplement will include full color videos of 3D display systems. Three-Dimensional Imaging, Visualization, and Display is suitable for electrical engineers, computer scientists, optical e...

  3. (Weakly) three-dimensional caseology

    International Nuclear Information System (INIS)

    Pomraning, G.C.

    1996-01-01

    The singular eigenfunction technique of Case for solving one-dimensional planar symmetry linear transport problems is extended to a restricted class of three-dimensional problems. This class involves planar geometry, but with forcing terms (either boundary conditions or internal sources) which are weakly dependent upon the transverse spatial variables. Our analysis involves a singular perturbation about the classic planar analysis, and leads to the usual Case discrete and continuum modes, but modulated by weakly dependent three-dimensional spatial functions. These functions satisfy parabolic differential equations, with a different diffusion coefficient for each mode. Representative one-speed time-independent transport problems are solved in terms of these generalised Case eigenfunctions. Our treatment is very heuristic, but may provide an impetus for more rigorous analysis. (author)

  4. Electron optical characteristics of a concave electrostatic electron mirror for a scanning electron microscope

    International Nuclear Information System (INIS)

    Hamarat, R.T.; Witzani, J.; Hoerl, E.M.

    1984-08-01

    Numerical computer calculations are used to explore the design characteristics of a concave electrostatic electron mirror for a mirror attachment for a conventional scanning electron microscope or an instrument designed totally as a scanning electron mirror microscope. The electron paths of a number of set-ups are calculated and drawn graphically in order to find the optimum shape and dimensions of the mirror geometry. This optimum configuration turns out to be the transition configuration between two cases of electron path deflection, towards the optical axis of the system and away from it. (Author)

  5. Equilibrium: three-dimensional configurations

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    This chapter considers toroidal MHD configurations that are inherently three-dimensional. The motivation for investigation such complicated equilibria is that they possess the potential for providing toroidal confinement without the need of a net toroidal current. This leads to a number of advantages with respect to fusion power generation. First, the attractive feature of steady-state operation becomes more feasible since such configurations no longer require a toroidal current transformer. Second, with zero net current, one potentially dangerous class of MHD instabilities, the current-driven kink modes, is eliminated. Finally, three-dimensional configurations possess nondegenerate flux surfaces even in the absence of plasma pressure and plasma current. Although there is an enormous range of possible three-dimensional equilibria, the configurations of interest are accurately described as axisymmetric tori with superimposed helical fields; furthermore, they possess no net toroidal current. Instead, two different and less obvious restoring forces are developed: the helical sideband force and the toroidal dipole current force. Each is discussed in detail in Chapter 7. A detailed discussion of the parallel current constraint, including its physical significance, is given in section 7.2. A general analysis of helical sideband equilibria, along with a detailed description of the Elmo bumpy torus, is presented in sections 7.3 and 7.4. A general description of toroidal dipole-current equilibria, including a detailed discussion of stellarators, heliotrons, and torsatrons, is given in sections 7.5 and 7.6

  6. Imaging differential polarization microscope with electronic readout

    International Nuclear Information System (INIS)

    Mickols, W.; Tinoco, I.; Katz, J.E.; Maestre, M.F.; Bustamante, C.

    1985-01-01

    A differential polarization microscope forms two images: one of the transmitted intensity and the other due to the change in intensity between images formed when different polarizations of light are used. The interpretation of these images for linear dichroism and circular dichroism are described. The design constraints on the data acquisition systems and the polarization modulation are described. The advantage of imaging several biological systems which contain optically anisotropic structures are described

  7. Quantitative methods for the analysis of electron microscope images

    DEFF Research Database (Denmark)

    Skands, Peter Ulrik Vallø

    1996-01-01

    The topic of this thesis is an general introduction to quantitative methods for the analysis of digital microscope images. The images presented are primarily been acquired from Scanning Electron Microscopes (SEM) and interfermeter microscopes (IFM). The topic is approached though several examples...... foundation of the thesis fall in the areas of: 1) Mathematical Morphology; 2) Distance transforms and applications; and 3) Fractal geometry. Image analysis opens in general the possibility of a quantitative and statistical well founded measurement of digital microscope images. Herein lies also the conditions...

  8. Scanning electron microscopic evaluation of root canal surfaces ...

    African Journals Online (AJOL)

    Scanning electron microscopic evaluation of root canal surfaces prepared with three rotary endodontic systems: Lightspeed, ProTaper and EndoWave. ... fracture with LightSpeed (LS), ProTaper (PT) and EndoWave (Ew) rotary instruments.

  9. Three Dimensional Double Layers in Magnetized Plasmas

    DEFF Research Database (Denmark)

    Jovanovic, D.; Lynov, Jens-Peter; Michelsen, Poul

    1982-01-01

    Experimental results are presented which demonstrate the formation of fully three dimensional double layers in a magnetized plasma. The measurements are performed in a magnetized stationary plasma column with radius 1.5 cm. Double layers are produced by introducing an electron beam with radius 0.......4 cm along the magnetic field from one end of the column. The voltage drop across the double layer is found to be determined by the energy of the incoming electron beam. In general we find that the width of the double layer along the external magnetic field is determined by plasma density and beam...

  10. Development of superconducting cryo-electron microscope and its applications

    International Nuclear Information System (INIS)

    Iwatsuki, Masashi

    1988-01-01

    Recently, a superconducting cryo-electron microscope in which specimens are cooled to the liquid helium temperature (4.2 K) has been developed. The main components and functional features of this new microscope are reported together with application data on polyethylene, poly (4-methyl-1-pentene), valonia cellulose, rock salt, ice crystallites and ceramic superconductor. The resistance to electron radiation damage, of beam-sensitive specimens including polymers has been increased more than ten times. Thus, the microscope has made it possible to take high resolution images and to analyze the crystal-structure of micro-areas. (orig.) [de

  11. Development of the Atomic-Resolution Environmental Transmission Electron Microscope

    DEFF Research Database (Denmark)

    Gai, Pratibha L.; Boyes, Edward D.; Yoshida, Kenta

    2016-01-01

    The development of the novel atomic-resolution environmental transmission electron microscope (atomic-resolution ETEM) for directly probing dynamic gas–solid reactions in situ at the atomic level under controlled reaction conditions consisting of gas environment and elevated temperatures is descr......The development of the novel atomic-resolution environmental transmission electron microscope (atomic-resolution ETEM) for directly probing dynamic gas–solid reactions in situ at the atomic level under controlled reaction conditions consisting of gas environment and elevated temperatures...... is used to study steels, graphene, nanowires, etc. In this chapter, the experimental setup of the microscope column and its peripherals are described....

  12. Simultaneous specimen and stage cleaning device for analytical electron microscope

    Science.gov (United States)

    Zaluzec, Nestor J.

    1996-01-01

    An improved method and apparatus are provided for cleaning both a specimen stage, a specimen and an interior of an analytical electron microscope (AEM). The apparatus for cleaning a specimen stage and specimen comprising a plasma chamber for containing a gas plasma and an air lock coupled to the plasma chamber for permitting passage of the specimen stage and specimen into the plasma chamber and maintaining an airtight chamber. The specimen stage and specimen are subjected to a reactive plasma gas that is either DC or RF excited. The apparatus can be mounted on the analytical electron microscope (AEM) for cleaning the interior of the microscope.

  13. Energy dispersive X-ray analysis in the electron microscope

    CERN Document Server

    Bell, DC

    2003-01-01

    This book provides an in-depth description of x-ray microanalysis in the electron microscope. It is sufficiently detailed to ensure that novices will understand the nuances of high-quality EDX analysis. Includes information about hardware design as well as the physics of x-ray generation, absorption and detection, and most post-detection data processing. Details on electron optics and electron probe formation allow the novice to make sensible adjustments to the electron microscope in order to set up a system which optimises analysis. It also helps the reader determine which microanalytical me

  14. Integration of a high-NA light microscope in a scanning electron microscope.

    Science.gov (United States)

    Zonnevylle, A C; Van Tol, R F C; Liv, N; Narvaez, A C; Effting, A P J; Kruit, P; Hoogenboom, J P

    2013-10-01

    We present an integrated light-electron microscope in which an inverted high-NA objective lens is positioned inside a scanning electron microscope (SEM). The SEM objective lens and the light objective lens have a common axis and focal plane, allowing high-resolution optical microscopy and scanning electron microscopy on the same area of a sample simultaneously. Components for light illumination and detection can be mounted outside the vacuum, enabling flexibility in the construction of the light microscope. The light objective lens can be positioned underneath the SEM objective lens during operation for sub-10 μm alignment of the fields of view of the light and electron microscopes. We demonstrate in situ epifluorescence microscopy in the SEM with a numerical aperture of 1.4 using vacuum-compatible immersion oil. For a 40-nm-diameter fluorescent polymer nanoparticle, an intensity profile with a FWHM of 380 nm is measured whereas the SEM performance is uncompromised. The integrated instrument may offer new possibilities for correlative light and electron microscopy in the life sciences as well as in physics and chemistry. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.

  15. Three-dimensional teletherapy treatment planning

    International Nuclear Information System (INIS)

    Panthaleon van Eck, R.B. van.

    1986-01-01

    This thesis deals with physical/mathematical backgrounds of computerized teletherapy treatment planning. The subjects discussed in this thesis can be subdivided into three main categories: a) Three-dimensional treatment planning. A method is evaluated which can be used for the purpose of simulation and optimization of dose distributions in three dimensions. b) The use of Computed Tomography. The use of patient information obtained from Computed Tomography for the purpose of dose computations is evaluated. c) Dose computational models for photon- and electron beams. Models are evaluated which provide information regarding the way in which the radiation dose is distributed in the patient (viz. is absorbed and/or dispersed). (Auth.)

  16. Electron microscope study of irradiated beryllium oxide

    International Nuclear Information System (INIS)

    Bisson, A.A.

    1965-06-01

    The beryllium oxide is studied first by fractography, before and after irradiation, using sintered samples. The fractures are examined under different aspects. The higher density sintered samples, with transgranular fractures are the most interesting for a microscopic study. It is possible to mark the difference between the 'pores' left by the sintering process and the 'bubbles' of gases that can be produced by former thermal treatments. After irradiation, the grain boundaries are very much weakened. By annealing, it is possible to observe the evolution of the gases produced by the reaction (n, 2n) and (n. α) and gathered on the grain boundaries. The irradiated beryllium oxide is afterwards studied by transmission. For that, a simple method has been used: little chips of the crushed material are examined. Clusters of point defects produced by neutrons are thus detected in crystals irradiated at the three following doses: 6 x 10 19 , 9 x 10 19 and 2 x 10 20 n f cm -2 at a temperature below 100 deg. C. For the irradiation at 6 x 10 19 n f cm -2 , the defects are merely visible, but at 2 x l0 20 n f cm -2 the crystals an crowded with clusters and the Kikuchi lines have disappeared from the micro-diffraction diagrams. The evolution of the clusters into dislocation loops is studied by a series of annealings. The activation energy (0,37 eV) calculated from the annealing curves suggests that it must be interstitials that condense into dislocation loops. Samples irradiated at high temperatures (650, 900 and 1100 deg. C) are also studied. In those specimens the size of the loops is not the same as the equilibrium size obtained after out of pile annealing at the same temperature. Those former loops are more specifically studied and their Burgers vector is determined by micro-diffraction. (author) [fr

  17. Three-dimensional aromatic networks.

    Science.gov (United States)

    Toyota, Shinji; Iwanaga, Tetsuo

    2014-01-01

    Three-dimensional (3D) networks consisting of aromatic units and linkers are reviewed from various aspects. To understand principles for the construction of such compounds, we generalize the roles of building units, the synthetic approaches, and the classification of networks. As fundamental compounds, cyclophanes with large aromatic units and aromatic macrocycles with linear acetylene linkers are highlighted in terms of transannular interactions between aromatic units, conformational preference, and resolution of chiral derivatives. Polycyclic cage compounds are constructed from building units by linkages via covalent bonds, metal-coordination bonds, or hydrogen bonds. Large cage networks often include a wide range of guest species in their cavity to afford novel inclusion compounds. Topological isomers consisting of two or more macrocycles are formed by cyclization of preorganized species. Some complicated topological networks are constructed by self-assembly of simple building units.

  18. Three-dimensional analytical model for the spatial variation of the foreshock electron distribution function - Systematics and comparisons with ISEE observations

    Science.gov (United States)

    Fitzenreiter, R. J.; Scudder, J. D.; Klimas, A. J.

    1990-01-01

    A model which is consistent with the solar wind and shock surface boundary conditions for the foreshock electron distribution in the absence of wave-particle effects is formulated for an arbitrary location behind the magnetic tangent to the earth's bow shock. Variations of the gyrophase-averaged velocity distribution are compared and contrasted with in situ ISEE observations. It is found that magnetic mirroring of solar wind electrons is the most important process by which nonmonotonic reduced electron distributions in the foreshock are produced. Leakage of particles from the magnetosheath is shown to be relatively unimportant in determining reduced distributions that are nonmonotonic. The two-dimensional distribution function off the magnetic field direction is the crucial contribution in producing reduced distributions which have beams. The time scale for modification of the electron velocity distribution in velocity space can be significantly influenced by steady state spatial gradients in the background imposed by the curved shock geometry.

  19. Shielded scanning electron microscope for radioactive samples

    International Nuclear Information System (INIS)

    Crouse, R.S.; Parsley, W.B.

    1977-01-01

    A small commercial SEM had been successfully shielded for examining radioactive materials transferred directly from a remote handling facility. Relatively minor mechanical modifications were required to achieve excellent operation. Two inches of steel provide adequate shielding for most samples encountered. However, samples reading 75 rad/hr γ have been examined by adding extra shielding in the form of tungsten sample holders and external lead shadow shields. Some degradation of secondary electron imaging was seen but was adequately compensated for by changing operating conditions

  20. Electron-microscopic autoradiography of tritiated testosterone in rat testis

    International Nuclear Information System (INIS)

    Frederik, P.M.; Molen, H.J. van der; Galjaard, H.; Klepper, D.

    1977-01-01

    The feasibility of a technique for autoradiography of diffusible substances has been further tested by analysing the localization of steroids in rats testes with the light- and electron-microscope. Testes of rats were perfused with tritiated testosterone (3 min) followed by 15-min perfusion with buffer containing a 100-fold excess of unlabelled testosterone. Tissue samples were frozen, freeze dried, fixed in osmium vapour and embedded in Epon. To exclude extraction of steroids, contact with water and other solvents was prevented during cutting of thin sections on an ultracryotome and further treatment for autoradiography. Light- and electron-microscopic observations indicated that the highest concentration of labelled testosterone was present within the basal parts of the Sertoli cell cytoplasm and in lipid inclusions of Sertoli cells within the seminiferous tubules. This is the first account of autoradiography of steroids at the electron-microscope level. (author)

  1. Analytical electron microscope study of eight ataxites

    Science.gov (United States)

    Novotny, P. M.; Goldstein, J. I.; Williams, D. B.

    1982-01-01

    Optical and electron optical (SEM, TEM, AEM) techniques were employed to investigate the fine structure of eight ataxite-iron meteorites. Structural studies indicated that the ataxites can be divided into two groups: a Widmanstaetten decomposition group and a martensite decomposition group. The Widmanstaetten decomposition group has a Type I plessite microstructure and the central taenite regions contain highly dislocated lath martensite. The steep M shaped Ni gradients in the taenite are consistent with the fast cooling rates, of not less than 500 C/my, observed for this group. The martensite decomposition group has a Type III plessite microstructure and contains all the chemical group IVB ataxites. The maximum taenite Ni contents vary from 47.5 to 52.7 wt % and are consistent with slow cooling to low temperatures of not greater than 350 C at cooling rates of not greater than 25 C/my.

  2. Electron microscope study of Sarcocystis sp

    Science.gov (United States)

    Zeve, V.H.; Price, D.L.; Herman, C.M.

    1966-01-01

    Sarcocystis sp. obtained from wild populations of grackles, Quiscalus quiscula (Linn.), were examined to clarify the effect of the parasite on the host. Electron micrographs are presented to show areas of muscle destruction adjacent to the parasite which appear to be mechanically produced by the parasite. The microtubules within the villus-like projections of the cyst suggest that their possible function is absorptive and/or conductive with regard to the production of a toxin or the conveyance of nutritive material to the developing cells. The proposed function of submembranous filaments and their relation to the conoid is discussed. Similarities in the ultrastructure to Toxoplasma and other protozoa tend to negate the relegation of Sarcocystis to the fungi and further emphasize its protozoan nature.

  3. Improvements to laser wakefield accelerated electron beam stability, divergence, and energy spread using three-dimensional printed two-stage gas cell targets

    International Nuclear Information System (INIS)

    Vargas, M.; Schumaker, W.; He, Z.-H.; Zhao, Z.; Behm, K.; Chvykov, V.; Hou, B.; Krushelnick, K.; Maksimchuk, A.; Yanovsky, V.; Thomas, A. G. R.

    2014-01-01

    High intensity, short pulse lasers can be used to accelerate electrons to ultra-relativistic energies via laser wakefield acceleration (LWFA) [T. Tajima and J. M. Dawson, Phys. Rev. Lett. 43, 267 (1979)]. Recently, it was shown that separating the injection and acceleration processes into two distinct stages could prove beneficial in obtaining stable, high energy electron beams [Gonsalves et al., Nat. Phys. 7, 862 (2011); Liu et al., Phys. Rev. Lett. 107, 035001 (2011); Pollock et al., Phys. Rev. Lett. 107, 045001 (2011)]. Here, we use a stereolithography based 3D printer to produce two-stage gas targets for LWFA experiments on the HERCULES laser system at the University of Michigan. We demonstrate substantial improvements to the divergence, pointing stability, and energy spread of a laser wakefield accelerated electron beam compared with a single-stage gas cell or gas jet target

  4. Improvements to laser wakefield accelerated electron beam stability, divergence, and energy spread using three-dimensional printed two-stage gas cell targets

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, M.; Schumaker, W.; He, Z.-H.; Zhao, Z.; Behm, K.; Chvykov, V.; Hou, B.; Krushelnick, K.; Maksimchuk, A.; Yanovsky, V.; Thomas, A. G. R., E-mail: agrt@umich.edu [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2014-04-28

    High intensity, short pulse lasers can be used to accelerate electrons to ultra-relativistic energies via laser wakefield acceleration (LWFA) [T. Tajima and J. M. Dawson, Phys. Rev. Lett. 43, 267 (1979)]. Recently, it was shown that separating the injection and acceleration processes into two distinct stages could prove beneficial in obtaining stable, high energy electron beams [Gonsalves et al., Nat. Phys. 7, 862 (2011); Liu et al., Phys. Rev. Lett. 107, 035001 (2011); Pollock et al., Phys. Rev. Lett. 107, 045001 (2011)]. Here, we use a stereolithography based 3D printer to produce two-stage gas targets for LWFA experiments on the HERCULES laser system at the University of Michigan. We demonstrate substantial improvements to the divergence, pointing stability, and energy spread of a laser wakefield accelerated electron beam compared with a single-stage gas cell or gas jet target.

  5. Dental Wear: A Scanning Electron Microscope Study

    Directory of Open Access Journals (Sweden)

    Luca Levrini

    2014-01-01

    Full Text Available Dental wear can be differentiated into different types on the basis of morphological and etiological factors. The present research was carried out on twelve extracted human teeth with dental wear (three teeth showing each type of wear: erosion, attrition, abrasion, and abfraction studied by scanning electron microscopy (SEM. The study aimed, through analysis of the macro- and micromorphological features of the lesions (considering the enamel, dentin, enamel prisms, dentinal tubules, and pulp, to clarify the different clinical and diagnostic presentations of dental wear and their possible significance. Our results, which confirm current knowledge, provide a complete overview of the distinctive morphology of each lesion type. It is important to identify the type of dental wear lesion in order to recognize the contributing etiological factors and, consequently, identify other more complex, nondental disorders (such as gastroesophageal reflux, eating disorders. It is clear that each type of lesion has a specific morphology and mechanism, and further clinical studies are needed to clarify the etiological processes, particularly those underlying the onset of abfraction.

  6. Scanning electron microscopic studies on bone tumors

    International Nuclear Information System (INIS)

    Itoh, Motoya

    1978-01-01

    Surface morphological observations of benign and malinant bone tumors were made by the use of scanning electron microscopy. Tumor materials were obtained directly from patients of osteogenic sarcomas, chondrosarcomas, enchondromas, giant cell tumors and Paget's sarcoma. To compare with these human tumors, the following experimental materials were also observed: P 32 -induced rat osteogenic sarcomas with their pulmonary metastatic lesions, Sr 89 -induced transplantable mouse osteogenic sarcomas and osteoid tissues arising after artificial fractures in mice. One of the most outstanding findings was a lot of granular substances seen on cell surfaces and their intercellular spaces in osteoid or chondroid forming tissues. These substances were considered to do some parts in collaborating extracellular matrix formation. Protrusions on cell surface, such as mucrovilli were more or less fashioned by these granular substances. Additional experiments revealed these substances to be soluble in sodium cloride solution. Benign osteoid forming cells, such as osteoblasts and osteoblastic osteosarcoma cells had granular substances on their surfaces and their intercellular spaces. On the other hand, undifferentiated transplantable osteosarcoma which formed on osteoid or chondroid matrix had none of these granular substances. Consequently, the difference of surface morphology between osteosarcoma cells and osteoblasts was yet to be especially concluded. (author)

  7. Scanning tunnel microscope with large vision field compatible with a scanning electron microscope

    International Nuclear Information System (INIS)

    Volodin, A.P.; Stepanyan, G.A.; Khajkin, M.S.; Ehdel'man, V.S.

    1989-01-01

    A scanning tunnel microscope (STM) with the 20μm vision field and 1nm resolution, designed to be compatible with a scanning electron microscope (SEM), is described. The sample scanning area is chosen within the 3x10mm limits with a 0.1-1μm step. The STM needle is moved automatically toward the sample surface from the maximum distance of 10mm until the tunneling current appears. Bimorphous elements of the KP-1 piezocorrector are used in the STM design. The device is installed on a table of SEM object holders

  8. Three-dimensional magnetophotonic crystals based on artificial opals

    Science.gov (United States)

    Baryshev, A. V.; Kodama, T.; Nishimura, K.; Uchida, H.; Inoue, M.

    2004-06-01

    We fabricated and experimentally investigated three-dimensional magnetophotonic crystals (3D MPCs) based on artificial opals. Opal samples with three-dimensional dielectric lattices were impregnated with different types of magnetic material. Magnetic and structural properties of 3D MPCs were studied by field emission scanning electron microscopy, x-ray diffraction analysis, and vibrating sample magnetometer. We have shown that magnetic materials synthesized in voids of opal lattices and the composites obtained have typical magnetic properties.

  9. Three-dimensional magnetophotonic crystals based on artificial opals

    International Nuclear Information System (INIS)

    Baryshev, A.V.; Kodama, T.; Nishimura, K.; Uchida, H.; Inoue, M.

    2004-01-01

    We fabricated and experimentally investigated three-dimensional magnetophotonic crystals (3D MPCs) based on artificial opals. Opal samples with three-dimensional dielectric lattices were impregnated with different types of magnetic material. Magnetic and structural properties of 3D MPCs were studied by field emission scanning electron microscopy, x-ray diffraction analysis, and vibrating sample magnetometer. We have shown that magnetic materials synthesized in voids of opal lattices and the composites obtained have typical magnetic properties

  10. Three-dimensional analytical model for the spatial variation of the foreshock electron distribution function: Systematics and comparisons with ISEE observations

    International Nuclear Information System (INIS)

    Fitzenreiter, R.J.; Scudder, J.D.; Klimas, A.J.

    1990-01-01

    A model of the gyrophase-averaged electron distribution in the Earth's foreshock consistent with boundary conditions at the bow shock and in the solar wind has been constructed according to the reversible guiding center characteristics and compared with ISEE electron and wave observations. This model demonstrates (1) that the basic features and morphology of beams in the observed and reduced distributions F(υ parallel ) are determined almost exclusively by the solar wind electrons mirrored at the shock's magnetic ramp and are relatively insensitive to the leakage fluxes from the magnetosheath, (2) that the wave particle modifications have been detected by contrasting the reversible model with the direct observations, (3) that the nonmonotonic reduced distributions F(υ parallel ) are rarely the result of a nonmonotonic energy spectra but are rather the result of the transverse velocity space integration necessary to produce F(υ parallel ) from the directly observed electron distribution function f(v), (4) that the time scale for beam resupply to F(υ parallel ) from the dc spatial gradients of the self-consistent reversible distribution function can have a factor of 100 variation across the foreshock, being shortest within a few degrees of the magnetic tangent surface, (5) that the beams predicted by the model have strongly varying and correlated variations of mean energy, thermal spread, and number density with angular departure from the magnetic tangent with the coldest, most tenuous, and lowest mean energy beams suggested to be present deep behind the magnetic tangent (≅5 degree-10 degree), and (6) that the lowest-energy beams have low contrast to the background solar wind distributing and although difficult to detect have beam density and temperature parameters compatible with ω pe growth of electrostatic waves

  11. Three-dimensional data assimilation and reanalysis of radiation belt electrons: Observations of a four-zone structure using five spacecraft and the VERB code

    Science.gov (United States)

    Kellerman, A. C.; Shprits, Y. Y.; Kondrashov, D.; Subbotin, D.; Makarevich, R. A.; Donovan, E.; Nagai, T.

    2014-11-01

    Obtaining the global state of radiation belt electrons through reanalysis is an important step toward validating our current understanding of radiation belt dynamics and for identification of new physical processes. In the current study, reanalysis of radiation belt electrons is achieved through data assimilation of five spacecraft with the 3-D Versatile Electron Radiation Belt (VERB) code using a split-operator Kalman filter technique. The spacecraft data are cleaned for noise, saturation effects, and then intercalibrated on an individual energy channel basis, by considering phase space density conjunctions in the T96 field model. Reanalysis during the CRRES era reveals a never-before-reported four-zone structure in the Earth's radiation belts during the 24 March 1991 shock-induced injection superstorm: (1) an inner belt, (2) the high-energy shock-injection belt, (3) a remnant outer radiation belt, and (4) a second outer radiation belt. The third belt formed near the same time as the second belt and was later enhanced across keV to MeV energies by a second particle injection observed by CRRES and the Northern Solar Terrestrial Array riometer network. During the recovery phase of the storm, the fourth belt was created near L*=4RE, lasting for several days. Evidence is provided that the fourth belt was likely created by a dominant local heating process. This study outlines the necessity to consider all diffusive processes acting simultaneously and the advantage of supporting ground-based data in quantifying the observed radiation belt dynamics. It is demonstrated that 3-D data assimilation can resolve various nondiffusive processes and provides a comprehensive picture of the electron radiation belts.

  12. Comprehensive study of out-of-plane transport properties in BaFe2As2 : Three-dimensional electronic state and effect of chemical substitution

    Science.gov (United States)

    Nakajima, M.; Nagafuchi, M.; Tajima, S.

    2018-03-01

    We investigated the out-of-plane transport properties of parent and chemically substituted BaFe2As2 for various types of substitution. Based on the studies of the Hall coefficient and chemical-substitution effect, we have clarified the origin for the unusual temperature dependence of out-of-plane resistivity ρc(T ) in the high-temperature paramagnetic-tetragonal phase. Electron (hole) carriers have an incoherent (coherent) character, which is responsible for nonmetallic (metallic) ρc(T ) . Although the electron and hole contributions are almost comparable, a slightly larger contribution comes from electrons at high temperatures but from holes at low temperatures, resulting in a maximum in ρc(T ) . In the low-temperature antiferromagnetic-orthorhombic phase, the major effect of substitution is to increase the residual-resistivity component, as in the case for the in-plane transport. In particular, Co atoms substituted for Fe give rise to strong scattering with large ac anisotropy. We found that K substitution induces a nonmetallic behavior in ρc(T ) at low temperatures, which is likely due to a weakly localized nature along the c -axis direction.

  13. Novel low-dose imaging technique for characterizing atomic structures through scanning transmission electron microscope

    Science.gov (United States)

    Su, Chia-Ping; Syu, Wei-Jhe; Hsiao, Chien-Nan; Lai, Ping-Shan; Chen, Chien-Chun

    2017-08-01

    To investigate dislocations or heterostructures across interfaces is now of great interest to condensed matter and materials scientists. With the advances in aberration-corrected electron optics, the scanning transmission electron microscope has demonstrated its excellent capability of characterizing atomic structures within nanomaterials, and well-resolved atomic-resolution images can be obtained through long-exposure data acquisition. However, the sample drifting, carbon contamination, and radiation damage hinder further analysis, such as deriving three-dimensional (3D) structures from a series of images. In this study, a method for obtaining atomic-resolution images with significantly reduced exposure time was developed, using which an original high-resolution image with approximately one tenth the electron dose can be obtained by combining a fast-scan high-magnification image and a slow-scan low-magnification image. The feasibility of obtaining 3D atomic structures using the proposed approach was demonstrated through multislice simulation. Finally, the feasibility and accuracy of image restoration were experimentally verified. This general method cannot only apply to electron microscopy but also benefit to image radiation-sensitive materials using various light sources.

  14. In-situ straining and time-resolved electron tomography data acquisition in a transmission electron microscope.

    Science.gov (United States)

    Hata, S; Miyazaki, S; Gondo, T; Kawamoto, K; Horii, N; Sato, K; Furukawa, H; Kudo, H; Miyazaki, H; Murayama, M

    2017-04-01

    This paper reports the preliminary results of a new in-situ three-dimensional (3D) imaging system for observing plastic deformation behavior in a transmission electron microscope (TEM) as a directly relevant development of the recently reported straining-and-tomography holder [Sato K et al. (2015) Development of a novel straining holder for transmission electron microscopy compatible with single tilt-axis electron tomography. Microsc. 64: 369-375]. We designed an integrated system using the holder and newly developed straining and image-acquisition software and then developed an experimental procedure for in-situ straining and time-resolved electron tomography (ET) data acquisition. The software for image acquisition and 3D visualization was developed based on the commercially available ET software TEMographyTM. We achieved time-resolved 3D visualization of nanometer-scale plastic deformation behavior in a Pb-Sn alloy sample, thus demonstrating the capability of this system for potential applications in materials science. © The Author 2016. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Three dimensional imaging of otoliths

    International Nuclear Information System (INIS)

    Barry, B.; Markwitz, A.; David, B.

    2008-01-01

    Otoliths are small structures in fish ears made of calcium carbonate which carry a record of the environment in which the fish live. Traditionally, in order to study their microchemistry by a scanning technique such as PIXE the otoliths have been either ground down by hand or thin sectioned to expose the otolith core. However this technique is subject to human error in judging the core position. In this study we have scanned successive layers of otoliths 50 and 100 μm apart by removing the otolith material in a lapping machine which can be set to a few μm precision. In one study by comparing data from otoliths from the two ears of a freshwater species we found that polishing by hand could miss the core and thus give misleading results as to the life cycle of the fish. In another example we showed detail in a marine species which could be used to build a three dimensional picture of the Sr distribution. (author)

  16. Three-Dimensional Rebar Graphene.

    Science.gov (United States)

    Sha, Junwei; Salvatierra, Rodrigo V; Dong, Pei; Li, Yilun; Lee, Seoung-Ki; Wang, Tuo; Zhang, Chenhao; Zhang, Jibo; Ji, Yongsung; Ajayan, Pulickel M; Lou, Jun; Zhao, Naiqin; Tour, James M

    2017-03-01

    Free-standing robust three-dimensional (3D) rebar graphene foams (GFs) were developed by a powder metallurgy template method with multiwalled carbon nanotubes (MWCNTs) as a reinforcing bar, sintered Ni skeletons as a template and catalyst, and sucrose as a solid carbon source. As a reinforcement and bridge between different graphene sheets and carbon shells, MWCNTs improved the thermostability, storage modulus (290.1 kPa) and conductivity (21.82 S cm -1 ) of 3D GF resulting in a high porosity and structurally stable 3D rebar GF. The 3D rebar GF can support >3150× the foam's weight with no irreversible height change, and shows only a ∼25% irreversible height change after loading >8500× the foam's weight. The 3D rebar GF also shows stable performance as a highly porous electrode in lithium ion capacitors (LICs) with an energy density of 32 Wh kg -1 . After 500 cycles of testing at a high current density of 6.50 mA cm -2 , the LIC shows 78% energy density retention. These properties indicate promising applications with 3D rebar GFs in devices requiring stable mechanical and electrochemical properties.

  17. Three-dimensional reconstruction of the naupliar musculature and a scanning electron microscopy atlas of nauplius development of Balanus improvisus (Crustacea

    DEFF Research Database (Denmark)

    Semmler, Henrike; Høeg, Jens Thorvald; Scholtz, Gerhard

    2009-01-01

    , as is the setation pattern of the first antennae. The naupliar musculature of B. improvisus was stained with phalloidin to visualise F-actin, followed by analysis using confocal laser scanning microscopy (CLSM) with subsequent application of 3D imaging software. The larval musculature is already fully established......An atlas of the naupliar development of the cirripede Balanus improvisus Darwin, 1854 using scanning electron microscopy (SEM) is provided. Existing spikes on the hindbody increase in number with each moult and are an applicable character for identification of the different nauplius stages...

  18. Formation of three-dimensional nano-porous silver films and application toward electrochemical detection of hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Junpeng [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Bian, Xiufang, E-mail: xfbian@sdu.edu.cn [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Niu, Yuchao [Department of Materials Science and Engineering, Shandong Jianzhu University, Fengming Road, Lingang Development Zone, Jinan 250101 (China); Bai, Yanwen; Xiao, Xinxin; Yang, Chuncheng; Yang, Jianfei; Yang, Jinyue [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China)

    2013-11-15

    By using the chemically dealloying method, three-dimensional nano-porous silver films (3-D NPSFs) are fabricated into a novel sensor for detecting hydrogen peroxide. The precursor films are prepared by high vacuum magnetron co-sputtering. High-resolution transmission electron microscope (HRTEM) and scanning electron microscope (SEM) are taken to investigate the structure and the micro morphology of the precursor films and nano-porous films. We find that the precursor films are composed of glassy matrix and nanocrystallines. After dealloying, the films exhibit a combination of homogenously distributed pores and silver filaments, and exhibit an open, three dimensional bicontinuous interpenetrating ligament–channel structure. Thickness and morphology of the films can be easily controlled by the sputtering time and alloy composition of the precursor films, respectively. In addition, NPSFs show a good linear responding for the concentration of hydrogen peroxide in phosphate buffered solutions, which indicates NPSFs could be a promising electrochemical material for hydrogen peroxide detection.

  19. Electron microscopic observation at low temperature on superconductors

    International Nuclear Information System (INIS)

    Yokota, Yasuhiro; Hashimoto, Hatsujiro; Yoshida, Hiroyuki.

    1991-01-01

    The authors have observed superconducting materials with a high resolution electron microscope at liquid helium temperature. First, observation was carried out on Nb system intermetallic compounds such as Nb 3 Al and Nb 3 Sn of Al 5 type and Nb 3 Ge of 11 type at extremely low temperature. Next, the observation of high temperature superconductive ceramics in the state of superconductivity was attempted. In this paper, first the development of the liquid helium sample holder for a 400 kV electron microscope to realize the observation is reported. Besides, the sample holder of Gatan Co. and an extremely low temperature, high resolution electron microscope with a superconducting lens are described. The purpose of carrying out the electron microscope observation of superconductors at low temperature is the direct observation of the crystalline lattice image in the state of superconductivity. Also the structural transformation from tetragonal crystals to rhombic crystals in Al 5 type superconductors can be observed. The results of observation are reported. (K.I.)

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  1. New Scanning Electron Microscope Used for Cryogenic Tensile Testing

    CERN Multimedia

    Maximilien Brice

    2013-01-01

    At CERN engineering department's installation for cryogenic tensile testing, the new scanning electron microscope (SEM) allows for detailed optical observations to be carried out. Using the SEM, surface coatings and tensile properties of materials can investigated in order to better understand how they behave under different conditions.

  2. On the resolution of the electron microscopic radioautography

    International Nuclear Information System (INIS)

    Uchida, Kazuko; Daimon, Tateo; Kawai, Kazuhiro

    1981-01-01

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

  3. Improved coating and fixation methods for scanning electron microscope autoradiography

    International Nuclear Information System (INIS)

    Weiss, R.L.

    1984-01-01

    A simple apparatus for emulsion coating is described. The apparatus is inexpensive and easily assembled in a standard glass shop. Emulsion coating for scanning electron microscope autoradiography with this apparatus consistently yields uniform layers. When used in conjunction with newly described fixation methods, this new approach produces reliable autoradiographs of undamaged specimens

  4. Scanning electron microscope facility for examination of radioactive materials

    International Nuclear Information System (INIS)

    Gibson, J.R.; Braski, D.N.

    1985-02-01

    An AMRAY model 1200B scanning electron microscope was modified to permit remote examination of radioactive specimens. Features of the modification include pneumatic vibration isolation of the column, motorized stage controls, improvements for monitoring vacuum, and a system for changing filaments without entering the hot cell

  5. Heat- and radiation-resistant scintillator for electron microscopes

    International Nuclear Information System (INIS)

    Kosov, A.V.; Petrov, S.A.; Puzyr', A.P.; Chetvergov, N.A.

    1987-01-01

    The use of a scintillator consisting of a single crystal of bismuth orthogermanate, which has high heat and radiation resistance, in REM-100, REM-200, and REM-100U electron microscopes is described. A study of the heat and radiation stabilities of single crystals of bismuth orthogermanate (Bi 4 Ge 3 O 12 ) has shown that they withstood multiple electron-beam heating redness (T ∼ 800 0 C) without changes in their properties

  6. Examples of electrostatic electron optics: The Farrand and Elektros microscopes and electron mirrors

    International Nuclear Information System (INIS)

    Hawkes, P.W.

    2012-01-01

    The role of Gertrude Rempfer in the design of the Farrand and Elektros microscopes is evoked. The study of electron mirror optics, aberration correction using mirrors and the development of microscopes employing electron mirrors are recapitulated, accompanied by a full bibliography, of earlier publications in particular.

  7. Response function and optimum configuration of semiconductor backscattered-electron detectors for scanning electron microscopes

    International Nuclear Information System (INIS)

    Rau, E. I.; Orlikovskiy, N. A.; Ivanova, E. S.

    2012-01-01

    A new highly efficient design for semiconductor detectors of intermediate-energy electrons (1–50 keV) for application in scanning electron microscopes is proposed. Calculations of the response function of advanced detectors and control experiments show that the efficiency of the developed devices increases on average twofold, which is a significant positive factor in the operation of modern electron microscopes in the mode of low currents and at low primary electron energies.

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

    International Nuclear Information System (INIS)

    Danilatos, Gerasimos; Kollia, Mary; Dracopoulos, Vassileios

    2015-01-01

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

  9. Comparative Analysis of the Oxygen Supply and Viability of Human Osteoblasts in Three-Dimensional Titanium Scaffolds Produced by Laser-Beam or Electron-Beam Melting

    Directory of Open Access Journals (Sweden)

    Anika Jonitz-Heincke

    2013-11-01

    Full Text Available Synthetic materials for bone replacement must ensure a sufficient mechanical stability and an adequate cell proliferation within the structures. Hereby, titanium materials are suitable for producing patient-individual porous bone scaffolds by using generative techniques. In this in vitro study, the viability of human osteoblasts was investigated in porous 3D Ti6Al4V scaffolds, which were produced by electron-beam (EBM or laser-beam melting (LBM. For each examination, two cylindrical scaffolds (30 mm × 10 mm in size, 700 µm × 700 µm macropores were placed on each other and seeded with cells. The oxygen consumption and the acidification in the center of the structures were investigated by means of microsensors. Additionally, the synthesis of pro-collagen type 1 was analyzed. On the LBM titanium scaffolds, vital bone cells were detected in the center and in the periphery after 8 days of cultivation. In the EBM titanium constructs, however, vital cells were only visible in the center. During the cultivation period, the cells increasingly produced procollagen type 1 in both scaffolds. In comparison to the periphery, the oxygen content in the center of the scaffolds slightly decreased. Furthermore, a slight acidification of the medium was detectable. Compared to LBM, the EBM titanium scaffolds showed a less favorable behavior with regard to cell seeding.

  10. Macrophages and dendritic cells in the rat meninges and choroid plexus: three-dimensional localisation by environmental scanning electron microscopy and confocal microscopy.

    Science.gov (United States)

    McMenamin, Paul G; Wealthall, Rosamund J; Deverall, Marie; Cooper, Stephanie J; Griffin, Brendan

    2003-09-01

    The present investigation provides novel information on the topographical distribution of macrophages and dendritic cells (DCs) in normal meninges and choroid plexus of the rat central nervous system (CNS). Whole-mounts of meninges and choroid plexus of Lewis rats were incubated with various anti-leucocyte monoclonal antibodies and either visualised with gold-conjugated secondary antibody followed by silver enhancement and subsequent examination by environmental scanning electron microscopy or by the use of fluorochromes and confocal microscopy. Large numbers of MHC class II(+) putative DCs were identified on the internal or subarachnoid aspect of dural whole-mounts, on the surface of the cortex (pia/arachnoid) and on the surface of the choroid plexus. Occupation of these sites would allow DCs access to cerebrospinal fluid (CSF) and therefore allow antigens into the subarachnoid space and ventricles. By contrast, macrophages were less evident at sites exposed to CSF and were more frequently located within the connective tissue of the dura/arachnoid and choroid plexus stroma and also in a sub-pial location. The present data suggest that DC may be strategically located within the CNS to sample CSF-borne antigens. Furthermore, the data suggest that CNS tissue samples collected without careful removal of the meninges may inadvertently be contaminated by DCs and meningeal macrophages.

  11. The use of combined three-dimensional electron backscatter diffraction and energy dispersive X-ray analysis to assess the characteristics of the gamma/gamma-prime microstructure in alloy 720Li™

    International Nuclear Information System (INIS)

    Child, D.J.; West, G.D.; Thomson, R.C.

    2012-01-01

    Multiple three-dimensional reconstructions of a γ/γ′ phase structure in Alloy 720Li have been carried out by employing a serial milling technique with simultaneous electron backscatter diffraction (EBSD) and energy dispersive x-ray (EDX) analysis data collection. Combining EBSD data with EDX is critical in obtaining maps to distinguish between the chemically differing, but crystallographically similar γ and γ′ phases present in the alloy studied. EDX is shown to allow the differentiation of γ and γ′ phases, with EBSD providing increased grain shape accuracy. The combination of data sources also allowed identification of coherent γ/γ′ phase interfaces that would not be identified using solely EBSD or EDX. The study identifies a region of grain banding within the alloy, which provides the basis for a three-dimensional comparison and discussion of γ′ phase size between coarse and fine grain regions, whilst also identifying coherent γ′ phase interfaces, possible only using both EDX and EBSD systems simultaneously. The majority of the γ′ phase lies in the range of 1–10 μm in non-banded regions, with a detectable particle size limit of 500 nm being established. The validity of the reconstruction has been demonstrated using an electron interaction volumes model, and an assessment of the validity of EBSD and EDX data sources is discussed showing γ′ phase connectivity in all dimensions. -- Highlights: ► Use of combined EBSD/EDX for the 3D analysis of gamma prime in a Ni-based alloy. ► Assessment of 3D reconstruction accuracy using CASINO. ► Observation and validation of gamma prime phase connectivity throughout the alloy. ► Identification and characterisation of grain banding in gamma prime. ► Distinction of phase coherency between gamma and gamma prime.

  12. The use of combined three-dimensional electron backscatter diffraction and energy dispersive X-ray analysis to assess the characteristics of the gamma/gamma-prime microstructure in alloy 720Li Trade-Mark-Sign

    Energy Technology Data Exchange (ETDEWEB)

    Child, D.J., E-mail: d.child@lboro.ac.uk [Department of Materials, Loughborough University, Loughborough, Leicestershire, LE11 3TU (United Kingdom); West, G.D., E-mail: g.west@lboro.ac.uk [Department of Materials, Loughborough University, Loughborough, Leicestershire, LE11 3TU (United Kingdom); Thomson, R.C., E-mail: r.c.thomson@lboro.ac.uk [Department of Materials, Loughborough University, Loughborough, Leicestershire, LE11 3TU (United Kingdom)

    2012-03-15

    Multiple three-dimensional reconstructions of a {gamma}/{gamma} Prime phase structure in Alloy 720Li have been carried out by employing a serial milling technique with simultaneous electron backscatter diffraction (EBSD) and energy dispersive x-ray (EDX) analysis data collection. Combining EBSD data with EDX is critical in obtaining maps to distinguish between the chemically differing, but crystallographically similar {gamma} and {gamma} Prime phases present in the alloy studied. EDX is shown to allow the differentiation of {gamma} and {gamma} Prime phases, with EBSD providing increased grain shape accuracy. The combination of data sources also allowed identification of coherent {gamma}/{gamma} Prime phase interfaces that would not be identified using solely EBSD or EDX. The study identifies a region of grain banding within the alloy, which provides the basis for a three-dimensional comparison and discussion of {gamma} Prime phase size between coarse and fine grain regions, whilst also identifying coherent {gamma} Prime phase interfaces, possible only using both EDX and EBSD systems simultaneously. The majority of the {gamma} Prime phase lies in the range of 1-10 {mu}m in non-banded regions, with a detectable particle size limit of 500 nm being established. The validity of the reconstruction has been demonstrated using an electron interaction volumes model, and an assessment of the validity of EBSD and EDX data sources is discussed showing {gamma} Prime phase connectivity in all dimensions. -- Highlights: Black-Right-Pointing-Pointer Use of combined EBSD/EDX for the 3D analysis of gamma prime in a Ni-based alloy. Black-Right-Pointing-Pointer Assessment of 3D reconstruction accuracy using CASINO. Black-Right-Pointing-Pointer Observation and validation of gamma prime phase connectivity throughout the alloy. Black-Right-Pointing-Pointer Identification and characterisation of grain banding in gamma prime. Black-Right-Pointing-Pointer Distinction of phase coherency

  13. Closed-Loop Autofocus Scheme for Scanning Electron Microscope

    Directory of Open Access Journals (Sweden)

    Cui Le

    2015-01-01

    Full Text Available In this paper, we present a full scale autofocus approach for scanning electron microscope (SEM. The optimal focus (in-focus position of the microscope is achieved by maximizing the image sharpness using a vision-based closed-loop control scheme. An iterative optimization algorithm has been designed using the sharpness score derived from image gradient information. The proposed method has been implemented and validated using a tungsten gun SEM at various experimental conditions like varying raster scan speed, magnification at real-time. We demonstrate that the proposed autofocus technique is accurate, robust and fast.

  14. Historical evolution toward achieving ultrahigh vacuum in JEOL electron microscopes

    CERN Document Server

    Yoshimura, Nagamitsu

    2014-01-01

    This book describes the developmental history of the vacuum system of the transmission electron microscope (TEM) at the Japan Electron Optics Laboratory (JEOL) from its inception to its use in today’s high-technology microscopes. The author and his colleagues were engaged in developing vacuum technology for electron microscopes (JEM series) at JEOL for many years. This volume presents a summary and explanation of their work and the technology that makes possible a clean ultrahigh vacuum. The typical users of the TEM are top-level researchers working at the frontiers of new materials or with new biological specimens. They often use the TEM under extremely severe conditions, with problems sometimes occurring in the vacuum system of the microscopes. JEOL engineers then must work as quickly as possible to improve the vacuum evacuation system so as to prevent the recurrence of such problems. Among the wealth of explanatory material in this book are examples of users’ reports of problems in the vacuum system of...

  15. Specimen holder for an electron microscope and device and method for mounting a specimen in an electron microscope

    NARCIS (Netherlands)

    Zandbergen, H.W.; Latenstein van Voorst, A.; Westra, C.; Hoveling, G.H.

    1996-01-01

    A specimen holder for an electron microscope, comprising a bar-shaped body provided adjacent one end with means for receiving a specimen, with means being present for screening the specimen from the environment at least temporarily in airtight and moisture-proof manner in a first position, which

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

    Science.gov (United States)

    Danilatos, Gerasimos; Kollia, Mary; Dracopoulos, Vassileios

    2015-03-01

    A transmission environmental scanning electron microscope with use of a scintillation gaseous detection device has been implemented. This corresponds to a transmission scanning electron microscope but with addition of a gaseous environment acting both as environmental and detection medium. A commercial type of low vacuum machine has been employed together with appropriate modifications to the detection configuration. This involves controlled screening of various emitted signals in conjunction with a scintillation gaseous detection device already provided with the machine for regular surface imaging. Dark field and bright field imaging has been obtained along with other detection conditions. With a progressive series of modifications and tests, the theory and practice of a novel type of microscopy is briefly shown now ushering further significant improvements and developments in electron microscopy as a whole. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Microscopic Electron Variations Measured Simultaneously By The Cluster Spacecraft

    Science.gov (United States)

    Buckley, A. M.; Carozzi, T. D.; Gough, M. P.; Beloff, N.

    Data is used from the Particle Correlator experiments running on each of the four Cluster spacecraft so as to determine common microscopic behaviour in the elec- tron population observed over the macroscopic Cluster separations. The Cluster par- ticle correlator experiments operate by forming on board Auto Correlation Functions (ACFs) generated from short time series of electron counts obtained, as a function of electron energy, from the PEACE HEEA sensor. The information on the microscopic variation of the electron flux covers the frequency range DC up to 41 kHz (encom- passing typical electron plasma frequencies and electron gyro frequencies and their harmonics), the electron energy range is that covered by the PEACE HEEA sensor (within the range 1 eV to 26 keV). Results are presented of coherent electron struc- tures observed simultaneously by the four spacecraft in the differing plasma interac- tion regions and boundaries encountered by Cluster. As an aid to understanding the plasma interactions, use is made of numerical simulations which model both the un- derlying statistical properties of the electrons and also the manner in which particle correlator experiments operate.

  18. Towards microscale electrohydrodynamic three-dimensional printing

    International Nuclear Information System (INIS)

    He, Jiankang; Xu, Fangyuan; Cao, Yi; Liu, Yaxiong; Li, Dichen

    2016-01-01

    It is challenging for the existing three-dimensional (3D) printing techniques to fabricate high-resolution 3D microstructures with low costs and high efficiency. In this work we present a solvent-based electrohydrodynamic 3D printing technique that allows fabrication of microscale structures like single walls, crossed walls, lattice and concentric circles. Process parameters were optimized to deposit tiny 3D patterns with a wall width smaller than 10 μm and a high aspect ratio of about 60. Tight bonding among neighbour layers could be achieved with a smooth lateral surface. In comparison with the existing microscale 3D printing techniques, the presented method is low-cost, highly efficient and applicable to multiple polymers. It is envisioned that this simple microscale 3D printing strategy might provide an alternative and innovative way for application in MEMS, biosensor and flexible electronics. (paper)

  19. Towards microscale electrohydrodynamic three-dimensional printing

    Science.gov (United States)

    He, Jiankang; Xu, Fangyuan; Cao, Yi; Liu, Yaxiong; Li, Dichen

    2016-02-01

    It is challenging for the existing three-dimensional (3D) printing techniques to fabricate high-resolution 3D microstructures with low costs and high efficiency. In this work we present a solvent-based electrohydrodynamic 3D printing technique that allows fabrication of microscale structures like single walls, crossed walls, lattice and concentric circles. Process parameters were optimized to deposit tiny 3D patterns with a wall width smaller than 10 μm and a high aspect ratio of about 60. Tight bonding among neighbour layers could be achieved with a smooth lateral surface. In comparison with the existing microscale 3D printing techniques, the presented method is low-cost, highly efficient and applicable to multiple polymers. It is envisioned that this simple microscale 3D printing strategy might provide an alternative and innovative way for application in MEMS, biosensor and flexible electronics.

  20. Acute radiation nephritis. Light and electron microscopic observations

    International Nuclear Information System (INIS)

    Kapur, S.; Chandra, R.; Antonovych, T.

    1977-01-01

    Light and electron microscopy were used to observe acute radiation nephritis. By light microscopy the changes were of fibrinoid necrosis of the arteries and arterioles with segmental necrosis of the glomerular tufts. By electron microscopy the endocapillary cells reacted by hypertrophy and hyperplasia with increase in cytoplasmic organelles. In addition, disruption of endothelial and epithelial cells from the basement membranes were seen. It is concluded that the electron microscopic changes were unique and may be helpful in differentiating the necrotizing glomerulitis seen in other conditions, especially malignant hypertension

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

    International Nuclear Information System (INIS)

    Taniguchi, Yoshifumi; Matsumoto, Hiroaki; Harada, Ken

    2012-01-01

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

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

    Science.gov (United States)

    Taniguchi, Yoshifumi; Matsumoto, Hiroaki; Harada, Ken

    2012-08-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Taniguchi, Yoshifumi [Science and Medical Systems Business Group, Hitachi High-Technologies Corp., Ichige, Hitachinaka, Ibaraki 312-8504 (Japan); Matsumoto, Hiroaki [Corporate Manufacturing Strategy Group, Hitachi High-Technologies Corp., Ishikawa-cho, Hitachinaka, Ibaraki 312-1991 (Japan); Harada, Ken [Central Research Laboratory, Hitachi Ltd., Hatoyama, Saitama 350-0395 (Japan)

    2012-08-27

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

  4. Use of a scanning electron microscope for examining radioactive materials

    International Nuclear Information System (INIS)

    Kauffmann, Yves; Prouve, Michel.

    1981-05-01

    The LAMA laboratory of the Grenoble Nuclear Research Center participates in studies carried out by research teams on fuels. Post-irradiation studies are performed on irradiated pins for research and development and safety programs. A scanning electron microscope was acquired for this purpose. This microscope had to fulfill certain criteria: it had to be sufficiently compact for it to be housed in a lead enclosure; it had to be capable of being adapted to operate with remote handling control. The modifications made to this microscope are briefly described together with the ancillary equipment of the cell. In parallel with these operations, an interconnection was realized enabling materials to be transferred between the various sampling and sample preparation cells and the microscope cell with a small transfer cask. After two years operating experience the microscope performance has been assessed satisfactory. The specific radioactivity of the samples themselves cannot be incriminated as the only cause of loss in resolution at magnifications greater than x 10,000 [fr

  5. Interpretation of data in the classical and three-dimensional β-autoradiography

    International Nuclear Information System (INIS)

    Rusov, V.D.; Semenov, M.Yu.; Babikova, Yu.F.

    1983-01-01

    Experimental test of theoretical model of electron-microscopic β-autoradiography is the main result of the work completing a certain stage of studies on the problems of unambiguous interpretation of autoradiograms. Native DNA molecules are used as linear sources. On the basis of experiments a method, permitting to obtain high-quality autoradiograms of linear β-sources, combined with their image, is developed. Justice of the theoretical model of autoradiography, i. e. adequacy of the restored ''actual'' location of β-sources and true geometry of their distribution on autoradiographic image, is proved on the basis of the method. Conclusion is made on real possibility of realization of not only classical (two-dimensional) but three-dimensional variant of electron-microscopic radiography

  6. Characterization of quantum well structures using a photocathode electron microscope

    Science.gov (United States)

    Spencer, Michael G.; Scott, Craig J.

    1989-01-01

    Present day integrated circuits pose a challenge to conventional electronic and mechanical test methods. Feature sizes in the submicron and nanometric regime require radical approaches in order to facilitate electrical contact to circuits and devices being tested. In addition, microwave operating frequencies require careful attention to distributed effects when considering the electrical signal paths within and external to the device under test. An alternative testing approach which combines the best of electrical and optical time domain testing is presented, namely photocathode electron microscope quantitative voltage contrast (PEMQVC).

  7. Characterization of highly anisotropic three-dimensionally nanostructured surfaces

    International Nuclear Information System (INIS)

    Schmidt, Daniel

    2014-01-01

    Generalized ellipsometry, a non-destructive optical characterization technique, is employed to determine geometrical structure parameters and anisotropic dielectric properties of highly spatially coherent three-dimensionally nanostructured thin films grown by glancing angle deposition. The (piecewise) homogeneous biaxial layer model approach is discussed, which can be universally applied to model the optical response of sculptured thin films with different geometries and from diverse materials, and structural parameters as well as effective optical properties of the nanostructured thin films are obtained. Alternative model approaches for slanted columnar thin films, anisotropic effective medium approximations based on the Bruggeman formalism, are presented, which deliver results comparable to the homogeneous biaxial layer approach and in addition provide film constituent volume fraction parameters as well as depolarization or shape factors. Advantages of these ellipsometry models are discussed on the example of metal slanted columnar thin films, which have been conformally coated with a thin passivating oxide layer by atomic layer deposition. Furthermore, the application of an effective medium approximation approach to in-situ growth monitoring of this anisotropic thin film functionalization process is presented. It was found that structural parameters determined with the presented optical model equivalents for slanted columnar thin films agree very well with scanning electron microscope image estimates. - Highlights: • Summary of optical model strategies for sculptured thin films with arbitrary geometries • Application of the rigorous anisotropic Bruggeman effective medium applications • In-situ growth monitoring of atomic layer deposition on biaxial metal slanted columnar thin film

  8. Pulsed Power for a Dynamic Transmission Electron Microscope

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-06-25

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

  9. Pulsed Power for a Dynamic Transmission Electron Microscope

    International Nuclear Information System (INIS)

    DeHope, W.J.; Browning, N.; Campbell, G.; Cook, E.; King, W.; Lagrange, T.; Reed, B.; Stuart, B.; Shuttlesworth, R.; Pyke, B.

    2009-01-01

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

  10. A new clustering algorithm for scanning electron microscope images

    Science.gov (United States)

    Yousef, Amr; Duraisamy, Prakash; Karim, Mohammad

    2016-04-01

    A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning it with a focused beam of electrons. The electrons interact with the sample atoms, producing various signals that are collected by detectors. The gathered signals contain information about the sample's surface topography and composition. The electron beam is generally scanned in a raster scan pattern, and the beam's position is combined with the detected signal to produce an image. The most common configuration for an SEM produces a single value per pixel, with the results usually rendered as grayscale images. The captured images may be produced with insufficient brightness, anomalous contrast, jagged edges, and poor quality due to low signal-to-noise ratio, grained topography and poor surface details. The segmentation of the SEM images is a tackling problems in the presence of the previously mentioned distortions. In this paper, we are stressing on the clustering of these type of images. In that sense, we evaluate the performance of the well-known unsupervised clustering and classification techniques such as connectivity based clustering (hierarchical clustering), centroid-based clustering, distribution-based clustering and density-based clustering. Furthermore, we propose a new spatial fuzzy clustering technique that works efficiently on this type of images and compare its results against these regular techniques in terms of clustering validation metrics.

  11. Elastocapillary fabrication of three-dimensional microstructures

    NARCIS (Netherlands)

    van Honschoten, J.W.; Berenschot, Johan W.; Ondarcuhu, T.; Sanders, Remco G.P.; Sundaram, J.; Elwenspoek, Michael Curt; Tas, Niels Roelof

    2010-01-01

    We describe the fabrication of three-dimensional microstructures by means of capillary forces. Using an origami-like technique, planar silicon nitride structures of various geometries are folded to produce three-dimensional objects of 50–100 m. Capillarity is a particularly effective mechanism since

  12. Role of scanning electron microscope )SEM) in metal failure analysis

    International Nuclear Information System (INIS)

    Shaiful Rizam Shamsudin; Hafizal Yazid; Mohd Harun; Siti Selina Abd Hamid; Nadira Kamarudin; Zaiton Selamat; Mohd Shariff Sattar; Muhamad Jalil

    2005-01-01

    Scanning electron microscope (SEM) is a scientific instrument that uses a beam of highly energetic electrons to examine the surface and phase distribution of specimens on a micro scale through the live imaging of secondary electrons (SE) and back-scattered electrons (BSE) images. One of the main activities of SEM Laboratory at MINT is for failure analysis on metal part and components. The capability of SEM is excellent for determining the root cause of metal failures such as ductility or brittleness, stress corrosion, fatigue and other types of failures. Most of our customers that request for failure analysis are from local petrochemical plants, manufacturers of automotive components, pipeline maintenance personnel and engineers who involved in the development of metal parts and component. This paper intends to discuss some of the technical concepts in failure analysis associated with SEM. (Author)

  13. A distributed multi-GPU system for high speed electron microscopic tomographic reconstruction

    International Nuclear Information System (INIS)

    Zheng, Shawn Q.; Branlund, Eric; Kesthelyi, Bettina; Braunfeld, Michael B.; Cheng, Yifan; Sedat, John W.; Agard, David A.

    2011-01-01

    Full resolution electron microscopic tomographic (EMT) reconstruction of large-scale tilt series requires significant computing power. The desire to perform multiple cycles of iterative reconstruction and realignment dramatically increases the pressing need to improve reconstruction performance. This has motivated us to develop a distributed multi-GPU (graphics processing unit) system to provide the required computing power for rapid constrained, iterative reconstructions of very large three-dimensional (3D) volumes. The participating GPUs reconstruct segments of the volume in parallel, and subsequently, the segments are assembled to form the complete 3D volume. Owing to its power and versatility, the CUDA (NVIDIA, USA) platform was selected for GPU implementation of the EMT reconstruction. For a system containing 10 GPUs provided by 5 GTX295 cards, 10 cycles of SIRT reconstruction for a tomogram of 4096 2 x512 voxels from an input tilt series containing 122 projection images of 4096 2 pixels (single precision float) takes a total of 1845 s of which 1032 s are for computation with the remainder being the system overhead. The same system takes only 39 s total to reconstruct 1024 2 x256 voxels from 122 1024 2 pixel projections. While the system overhead is non-trivial, performance analysis indicates that adding extra GPUs to the system would lead to steadily enhanced overall performance. Therefore, this system can be easily expanded to generate superior computing power for very large tomographic reconstructions and especially to empower iterative cycles of reconstruction and realignment. -- Highlights: → A distributed multi-GPU system has been developed for electron microscopic tomography (EMT). → This system allows for rapid constrained, iterative reconstruction of very large volumes. → This system can be easily expanded to generate superior computing power for large-scale iterative EMT realignment.

  14. A distributed multi-GPU system for high speed electron microscopic tomographic reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Shawn Q.; Branlund, Eric; Kesthelyi, Bettina; Braunfeld, Michael B.; Cheng, Yifan; Sedat, John W. [The Howard Hughes Medical Institute and the W.M. Keck Advanced Microscopy Laboratory, Department of Biochemistry and Biophysics, University of California, San Francisco, 600, 16th Street, Room S412D, CA 94158-2517 (United States); Agard, David A., E-mail: agard@msg.ucsf.edu [The Howard Hughes Medical Institute and the W.M. Keck Advanced Microscopy Laboratory, Department of Biochemistry and Biophysics, University of California, San Francisco, 600, 16th Street, Room S412D, CA 94158-2517 (United States)

    2011-07-15

    Full resolution electron microscopic tomographic (EMT) reconstruction of large-scale tilt series requires significant computing power. The desire to perform multiple cycles of iterative reconstruction and realignment dramatically increases the pressing need to improve reconstruction performance. This has motivated us to develop a distributed multi-GPU (graphics processing unit) system to provide the required computing power for rapid constrained, iterative reconstructions of very large three-dimensional (3D) volumes. The participating GPUs reconstruct segments of the volume in parallel, and subsequently, the segments are assembled to form the complete 3D volume. Owing to its power and versatility, the CUDA (NVIDIA, USA) platform was selected for GPU implementation of the EMT reconstruction. For a system containing 10 GPUs provided by 5 GTX295 cards, 10 cycles of SIRT reconstruction for a tomogram of 4096{sup 2}x512 voxels from an input tilt series containing 122 projection images of 4096{sup 2} pixels (single precision float) takes a total of 1845 s of which 1032 s are for computation with the remainder being the system overhead. The same system takes only 39 s total to reconstruct 1024{sup 2}x256 voxels from 122 1024{sup 2} pixel projections. While the system overhead is non-trivial, performance analysis indicates that adding extra GPUs to the system would lead to steadily enhanced overall performance. Therefore, this system can be easily expanded to generate superior computing power for very large tomographic reconstructions and especially to empower iterative cycles of reconstruction and realignment. -- Highlights: {yields} A distributed multi-GPU system has been developed for electron microscopic tomography (EMT). {yields} This system allows for rapid constrained, iterative reconstruction of very large volumes. {yields} This system can be easily expanded to generate superior computing power for large-scale iterative EMT realignment.

  15. Classification of heterogeneous electron microscopic projections into homogeneous subsets

    International Nuclear Information System (INIS)

    Herman, G.T.; Kalinowski, M.

    2008-01-01

    The co-existence of different states of a macromolecular complex in samples used by three-dimensional electron microscopy (3D-EM) constitutes a serious challenge. The single particle method applied directly to such heterogeneous sets is unable to provide useful information about the encountered conformational diversity and produces reconstructions with severely reduced resolution. One approach to solving this problem is to partition heterogeneous projection set into homogeneous components and apply existing reconstruction techniques to each of them. Due to the nature of the projection images and the high noise level present in them, this classification task is difficult. A method is presented to achieve the desired classification by using a novel image similarity measure and solving the corresponding optimization problem. Unlike the majority of competing approaches, the presented method employs unsupervised classification (it does not require any prior knowledge about the objects being classified) and does not involve a 3D reconstruction procedure. We demonstrate a fast implementation of this method, capable of classifying projection sets that originate from 3D-EM. The method's performance is evaluated on synthetically generated data sets produced by projecting 3D objects that resemble biological structures

  16. Electron irradiation-induced destruction of carbon nanotubes in electron microscopes

    International Nuclear Information System (INIS)

    Molhave, Kristian; Gudnason, Sven Bjarke; Pedersen, Anders Tegtmeier; Clausen, Casper Hyttel; Horsewell, Andy; Boggild, Peter

    2007-01-01

    Observations of carbon nanotubes under exposure to electron beam irradiation in standard transmission electron microscope (TEM) and scanning electron microscope (SEM) systems show that such treatment in some cases can cause severe damage of the nanotube structure, even at electron energies far below the approximate 100 keV threshold for knock-on damage displacing carbon atoms in the graphene structure. We find that the damage we observe in one TEM can be avoided by use of a cold finger. This and the morphology of the damage imply that water vapour, which is present as a background gas in many vacuum chambers, can damage the nanotube structure through electron beam-induced chemical reactions. Though, the dependence on the background gas makes these observations specific for the presently used systems, the results demonstrate the importance of careful assessment of the level of subtle structural damage that the individual electron microscope system can do to nanostructures during standard use

  17. Microscopic Electron Dynamics in Metal Nanoparticles for Photovoltaic Systems

    Directory of Open Access Journals (Sweden)

    Katarzyna Kluczyk

    2018-06-01

    Full Text Available Nanoparticles—regularly patterned or randomly dispersed—are a key ingredient for emerging technologies in photonics. Of particular interest are scattering and field enhancement effects of metal nanoparticles for energy harvesting and converting systems. An often neglected aspect in the modeling of nanoparticles are light interaction effects at the ultimate nanoscale beyond classical electrodynamics. Those arise from microscopic electron dynamics in confined systems, the accelerated motion in the plasmon oscillation and the quantum nature of the free electron gas in metals, such as Coulomb repulsion and electron diffusion. We give a detailed account on free electron phenomena in metal nanoparticles and discuss analytic expressions stemming from microscopic (Random Phase Approximation—RPA and semi-classical (hydrodynamic theories. These can be incorporated into standard computational schemes to produce more reliable results on the optical properties of metal nanoparticles. We combine these solutions into a single framework and study systematically their joint impact on isolated Au, Ag, and Al nanoparticles as well as dimer structures. The spectral position of the plasmon resonance and its broadening as well as local field enhancement show an intriguing dependence on the particle size due to the relevance of additional damping channels.

  18. Cooled CCDs for recording data from electron microscopes

    CERN Document Server

    Faruqi, A R

    2000-01-01

    A cooled-CCD camera based on a low-noise scientific grade device is described in this paper used for recording images in a 120 kV electron microscope. The primary use of the camera is for recording electron diffraction patterns from two-dimensionally ordered arrays of proteins at liquid-nitrogen temperatures leading to structure determination at atomic or near-atomic resolution. The traditional method for recording data in the microscope is with electron sensitive film but electronic detection methods offer the following advantages over film methods: the data is immediately available in a digital format which can be displayed on a monitor screen for visual inspection whereas a film record needs to be developed and digitised, a lengthy process taking at least several hours, prior to inspection; the dynamic range of CCD detectors is about two orders of magnitude greater with better linearity. The accuracy of measurements is also higher for CCDs, particularly for weak signals due to inherent fog levels in film. ...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-08-04

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

  20. In situ laser processing in a scanning electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Nicholas A.; Magel, Gregory A.; Hartfield, Cheryl D.; Moore, Thomas M.; Fowlkes, Jason D.; Rack, Philip D. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States) and Omniprobe, Inc., an Oxford Instruments Company, 10410 Miller Rd., Dallas, Texas 75238 (United States); Omniprobe, Inc., an Oxford Instruments Company, 10410 Miller Rd., Dallas, Texas 75238 (United States); Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States) and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2012-07-15

    Laser delivery probes using multimode fiber optic delivery and bulk focusing optics have been constructed and used for performing materials processing experiments within scanning electron microscope/focused ion beam instruments. Controlling the current driving a 915-nm semiconductor diode laser module enables continuous or pulsed operation down to sub-microsecond durations, and with spot sizes on the order of 50 {mu}m diameter, achieving irradiances at a sample surface exceeding 1 MW/cm{sup 2}. Localized laser heating has been used to demonstrate laser chemical vapor deposition of Pt, surface melting of silicon, enhanced purity, and resistivity via laser annealing of Au deposits formed by electron beam induced deposition, and in situ secondary electron imaging of laser induced dewetting of Au metal films on SiO{sub x}.

  1. Comparison study of the partial-breast irradiation techniques: Dosimetric analysis of three-dimensional conformal radiation therapy, electron beam therapy, and helical tomotherapy depending on various tumor locations

    International Nuclear Information System (INIS)

    Kim, Min-Joo; Park, So-Hyun; Son, Seok-Hyun; Cheon, Keum-Seong; Choi, Byung-Ock; Suh, Tae-Suk

    2013-01-01

    The partial-breast irradiation (PBI) technique, an alternative to whole-breast irradiation, is a beam delivery method that uses a limited range of treatment volume. The present study was designed to determine the optimal PBI treatment modalities for 8 different tumor locations. Treatment planning was performed on computed tomography (CT) data sets of 6 patients who had received lumpectomy treatments. Tumor locations were classified into 8 subsections according to breast quadrant and depth. Three-dimensional conformal radiation therapy (3D-CRT), electron beam therapy (ET), and helical tomotherapy (H-TOMO) were utilized to evaluate the dosimetric effect for each tumor location. Conformation number (CN), radical dose homogeneity index (rDHI), and dose delivered to healthy tissue were estimated. The Kruskal-Wallis, Mann-Whitney U, and Bonferroni tests were used for statistical analysis. The ET approach showed good sparing effects and acceptable target coverage for the lower inner quadrant—superficial (LIQ-S) and lower inner quadrant—deep (LIQ-D) locations. The H-TOMO method was the least effective technique as no evaluation index achieved superiority for all tumor locations except CN. The ET method is advisable for treating LIQ-S and LIQ-D tumors, as opposed to 3D-CRT or H-TOMO, because of acceptable target coverage and much lower dose applied to surrounding tissue

  2. Characteristics of different frequency ranges in scanning electron microscope images

    International Nuclear Information System (INIS)

    Sim, K. S.; Nia, M. E.; Tan, T. L.; Tso, C. P.; Ee, C. S.

    2015-01-01

    We demonstrate a new approach to characterize the frequency range in general scanning electron microscope (SEM) images. First, pure frequency images are generated from low frequency to high frequency, and then, the magnification of each type of frequency image is implemented. By comparing the edge percentage of the SEM image to the self-generated frequency images, we can define the frequency ranges of the SEM images. Characterization of frequency ranges of SEM images benefits further processing and analysis of those SEM images, such as in noise filtering and contrast enhancement

  3. Characteristics of different frequency ranges in scanning electron microscope images

    Energy Technology Data Exchange (ETDEWEB)

    Sim, K. S., E-mail: kssim@mmu.edu.my; Nia, M. E.; Tan, T. L.; Tso, C. P.; Ee, C. S. [Faculty of Engineering and Technology, Multimedia University, 75450 Melaka (Malaysia)

    2015-07-22

    We demonstrate a new approach to characterize the frequency range in general scanning electron microscope (SEM) images. First, pure frequency images are generated from low frequency to high frequency, and then, the magnification of each type of frequency image is implemented. By comparing the edge percentage of the SEM image to the self-generated frequency images, we can define the frequency ranges of the SEM images. Characterization of frequency ranges of SEM images benefits further processing and analysis of those SEM images, such as in noise filtering and contrast enhancement.

  4. Fabrication and electric measurements of nanostructures inside transmission electron microscope.

    Science.gov (United States)

    Chen, Qing; Peng, Lian-Mao

    2011-06-01

    Using manipulation holders specially designed for transmission electron microscope (TEM), nanostructures can be characterized, measured, modified and even fabricated in-situ. In-situ TEM techniques not only enable real-time study of structure-property relationships of materials at atomic scale, but also provide the ability to control and manipulate materials and structures at nanoscale. This review highlights in-situ electric measurements and in-situ fabrication and structure modification using manipulation holder inside TEM. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Computational methods for three-dimensional microscopy reconstruction

    CERN Document Server

    Frank, Joachim

    2014-01-01

    Approaches to the recovery of three-dimensional information on a biological object, which are often formulated or implemented initially in an intuitive way, are concisely described here based on physical models of the object and the image-formation process. Both three-dimensional electron microscopy and X-ray tomography can be captured in the same mathematical framework, leading to closely-related computational approaches, but the methodologies differ in detail and hence pose different challenges. The editors of this volume, Gabor T. Herman and Joachim Frank, are experts in the respective methodologies and present research at the forefront of biological imaging and structural biology.   Computational Methods for Three-Dimensional Microscopy Reconstruction will serve as a useful resource for scholars interested in the development of computational methods for structural biology and cell biology, particularly in the area of 3D imaging and modeling.

  6. Development of spin-polarized transmission electron microscope

    International Nuclear Information System (INIS)

    Kuwahara, M; Saitoh, K; Tanaka, N; Takeda, Y; Ujihara, T; Asano, H; Nakanishi, T

    2011-01-01

    In order to study spin related phenomena in nano-size materials, spin-polarized electron source (PES) has been employed for the incident beam in transmission electron microscope (TEM). The PES has been designed and constructed with optimizing for spin-polarized TEM. The illuminating system of TEM is also designed to focus the spin-polarized electron beam emitted from a semiconductor photocathode with a negative electron affinity (NEA) surface. The beam energy is set to below 40 keV which is lower energy type as a TEM, because the spin interaction with condensed matters is very small corresponding with a Coulomb interaction. The polarized electron gun has realized in an extra high vacuum (XHV) condition and high field gradient of 4 MV/m on a surface of photocathode. Furthermore, it demonstrated that 40-keV polarized electron beam was operated with a sub-milli second pulse mode by using the backside excitation type photocathode. This high performance PES will make it possible to observe dynamically a magnetic field images with high contrast and highspeed temporal imaging in TEM.

  7. Coupling auto trophic in vitro plant cultivation system to scanning electron microscope to study plant-fungal interactions

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, N. de; Decock, C.; Declereck, S.; Providencia, I. E. de la

    2010-07-01

    The interactions of plants with pathogens and beneficial micro-organisms have been seldom compared on the same host and under strict controlled auto trophic in vitro culture conditions. Here, the life cycle of two plant beneficial (Glomus sp. MUCL 41833 and Trichoderma harzianum) and one plant pathogen (Rhizoctonia solani) fungi were described on potato (Solanum tuberosum) plantlets under auto trophic in vitro culture conditions using video camera imaging and the scanning electron microscope (SEM). (i) The colony developmental pattern of the extraradical mycelium within the substrate, (ii) the reproduction structures and (iii) the three-dimensional spatial arrangements of the fungal hyphae within the potato root cells were successfully visualized, monitored and described. The combination of the autotrophic in vitro culture system and SEM represent a powerful tool for improving our knowledge on the dynamics of plant-fungal interactions. (Author) 41 refs.

  8. Multimodal three-dimensional dynamic signature

    Directory of Open Access Journals (Sweden)

    Yury E. Kozlov

    2017-11-01

    Full Text Available Reliable authentication in mobile applications is among the most important information security challenges. Today, we can hardly imagine a person who would not own a mobile device that connects to the Internet. Mobile devices are being used to store large amounts of confidential information, ranging from personal photos to electronic banking tools. In 2009, colleagues from Rice University together with their collaborators from Motorola, proposed an authentication through in-air gestures. This and subsequent work contributing to the development of the method are reviewed in our introduction. At the moment, there exists a version of the gesture-based authentication software available for Android mobile devices. This software has not become widespread yet. One of likely reasons for that is the insufficient reliability of the method, which involves similar to its earlier analogs the use of only one device. Here we discuss the authentication based on the multimodal three-dimensional dynamic signature (MTDS performed by two independent mobile devices. The MTDS-based authentication technique is an advanced version of in-air gesture authentication. We describe the operation of a prototype of MTDS-based authentication, including the main implemented algorithms, as well as some preliminary results of testing the software. We expect that our method can be used in any mobile application, provided a number of additional improvements discussed in the conclusion are made.

  9. Three dimensional visualization of medical images

    International Nuclear Information System (INIS)

    Suto, Yasuzo

    1992-01-01

    Three dimensional visualization is a stereoscopic technique that allows the diagnosis and treatment of complicated anatomy site of the bone and organ. In this article, the current status and technical application of three dimensional visualization are introduced with special reference to X-ray CT and MRI. The surface display technique is the most common for three dimensional visualization, consisting of geometric model, voxel element, and stereographic composition techniques. Recent attention has been paid to display method of the content of the subject called as volume rendering, whereby information on the living body is provided accurately. The application of three dimensional visualization is described in terms of diagnostic imaging and surgical simulation. (N.K.)

  10. three dimensional photoelastic investigations on thick rectangular

    African Journals Online (AJOL)

    user

    1983-09-01

    Sep 1, 1983 ... Thick rectangular plates are investigated by means of three-dimensional photoelasticity ... a thin plate theory and a higher order thick plate theory. 1. ..... number of fringes lest the accuracy of the results will be considerably.

  11. Three dimensional diffusion calculations of nuclear reactors

    International Nuclear Information System (INIS)

    Caspo, N.

    1981-07-01

    This work deals with the three dimensional calculation of nuclear reactors using the code TRITON. The purposes of the work were to perform three-dimensional computations of the core of the Soreq nuclear reactor and of the power reactor ZION and to validate the TRITON code. Possible applications of the TRITON code in Soreq reactor calculations and in power reactor research are suggested. (H.K.)

  12. Electric field stimulation setup for photoemission electron microscopes.

    Science.gov (United States)

    Buzzi, M; Vaz, C A F; Raabe, J; Nolting, F

    2015-08-01

    Manipulating magnetisation by the application of an electric field in magnetoelectric multiferroics represents a timely issue due to the potential applications in low power electronics and the novel physics involved. Thanks to its element sensitivity and high spatial resolution, X-ray photoemission electron microscopy is a uniquely suited technique for the investigation of magnetoelectric coupling in multiferroic materials. In this work, we present a setup that allows for the application of in situ electric and magnetic fields while the sample is analysed in the microscope. As an example of the performances of the setup, we present measurements on Ni/Pb(Mg(0.66)Nb(0.33))O3-PbTiO3 and La(0.7)Sr(0.3)MnO3/PMN-PT artificial multiferroic nanostructures.

  13. Resizing metal-coated nanopores using a scanning electron microscope.

    Science.gov (United States)

    Chansin, Guillaume A T; Hong, Jongin; Dusting, Jonathan; deMello, Andrew J; Albrecht, Tim; Edel, Joshua B

    2011-10-04

    Electron beam-induced shrinkage provides a convenient way of resizing solid-state nanopores in Si(3) N(4) membranes. Here, a scanning electron microscope (SEM) has been used to resize a range of different focussed ion beam-milled nanopores in Al-coated Si(3) N(4) membranes. Energy-dispersive X-ray spectra and SEM images acquired during resizing highlight that a time-variant carbon deposition process is the dominant mechanism of pore shrinkage, although granular structures on the membrane surface in the vicinity of the pores suggest that competing processes may occur. Shrinkage is observed on the Al side of the pore as well as on the Si(3) N(4) side, while the shrinkage rate is observed to be dependent on a variety of factors. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Three-dimensional effects in fracture mechanics

    International Nuclear Information System (INIS)

    Benitez, F.G.

    1991-01-01

    An overall view of the pioneering theories and works, which enlighten the three-dimensional nature of fracture mechanics during the last years is given. the main aim is not an exhaustive reviewing but the displaying of the last developments on this scientific field in a natural way. This work attempts to envisage the limits of disregarding the three-dimensional behaviour in theories, analyses and experiments. Moreover, it tries to draw attention on the scant fervour, although increasing, this three-dimensional nature of fracture has among the scientific community. Finally, a constructive discussion is presented on the use of two-dimensional solutions in the analysis of geometries which bear a three-dimensional configuration. the static two-dimensional solutions and its applications fields are reviewed. also, the static three-dimensional solutions, wherein a comparative analysis with elastoplastic and elastostatic solutions are presented. to end up, the dynamic three-dimensional solutions are compared to the asymptotic two-dimensional ones under the practical applications point of view. (author)

  15. Spinning Carbon Nanotube Nanothread under a Scanning Electron Microscope

    Directory of Open Access Journals (Sweden)

    Mark Schulz

    2011-08-01

    Full Text Available Nanothread with a diameter as small as one hundred nanometers was manufactured under a scanning electron microscope. Made directly from carbon nanotubes, and inheriting their superior electrical and mechanical properties, nanothread may be the world’s smallest man-made fiber. The smallest thread that can be spun using a bench-top spinning machine is about 5 microns in diameter. Nanothread is a new material building block that can be used at the nanoscale or plied to form yarn for applications at the micro and macro scales. Preliminary electrical and mechanical properties of nanothread were measured. The resistivity of nanothread is less than 10−5 Ω∙m. The strength of nanothread is greater than 0.5 GPa. This strength was obtained from measurements using special glue that cures in an electron microscope. The glue weakened the thread, thus further work is needed to obtain more accurate measurements. Nanothread will have broad applications in enabling electrical components, circuits, sensors, and tiny machines. Yarn can be used for various macroscale applications including lightweight antennas, composites, and cables.

  16. Scanning electron microscope autoradiography of critical point dried biological samples

    International Nuclear Information System (INIS)

    Weiss, R.L.

    1980-01-01

    A technique has been developed for the localization of isotopes in the scanning electron microscope. Autoradiographic studies have been performed using a model system and a unicellular biflagellate alga. One requirement of this technique is that all manipulations be carried out on samples that are maintained in a liquid state. Observations of a source of radiation ( 125 I-ferritin) show that the nuclear emulsion used to detect radiation is active under these conditions. Efficiency measurement performed using 125 I-ferritin indicate that 125 I-SEM autoradiography is an efficient process that exhibits a 'dose dependent' response. Two types of labeling methods were used with cells, surface labeling with 125 I and internal labeling with 3 H. Silver grains appeared on labeled cells after autoradiography, removal of residual gelatin and critical point drying. The location of grains was examined on a flagellated green alga (Chlamydomonas reinhardi) capable of undergoing cell fusion. Fusion experiments using labeled and unlabeled cells indicate that 1. Labeling is specific for incorporated radioactivity; 2. Cell surface structure is preserved in SEM autoradiographs and 3. The technique appears to produce reliable autoradiographs. Thus scanning electron microscope autoradiography should provide a new and useful experimental approach

  17. Development of a secondary electron energy analyzer for a transmission electron microscope.

    Science.gov (United States)

    Magara, Hideyuki; Tomita, Takeshi; Kondo, Yukihito; Sato, Takafumi; Akase, Zentaro; Shindo, Daisuke

    2018-04-01

    A secondary electron (SE) energy analyzer was developed for a transmission electron microscope. The analyzer comprises a microchannel plate (MCP) for detecting electrons, a coil for collecting SEs emitted from the specimen, a tube for reducing the number of backscattered electrons incident on the MCP, and a retarding mesh for selecting the energy of SEs incident on the MCP. The detection of the SEs associated with charging phenomena around a charged specimen was attempted by performing electron holography and SE spectroscopy using the energy analyzer. The results suggest that it is possible to obtain the energy spectra of SEs using the analyzer and the charging states of a specimen by electron holography simultaneously.

  18. Miniaturized Environmental Scanning Electron Microscope for In Situ Planetary Studies

    Science.gov (United States)

    Gaskin, Jessica; Abbott, Terry; Medley, Stephanie; Gregory, Don; Thaisen, Kevin; Taylor , Lawrence; Ramsey, Brian; Jerman, Gregory; Sampson, Allen; Harvey, Ralph

    2010-01-01

    The exploration of remote planetary surfaces calls for the advancement of low power, highly-miniaturized instrumentation. Instruments of this nature that are capable of multiple types of analyses will prove to be particularly useful as we prepare for human return to the moon, and as we continue to explore increasingly remote locations in our Solar System. To this end, our group has been developing a miniaturized Environmental-Scanning Electron Microscope (mESEM) capable of remote investigations of mineralogical samples through in-situ topographical and chemical analysis on a fine scale. The functioning of an SEM is well known: an electron beam is focused to nanometer-scale onto a given sample where resulting emissions such as backscattered and secondary electrons, X-rays, and visible light are registered. Raster scanning the primary electron beam across the sample then gives a fine-scale image of the surface topography (texture), crystalline structure and orientation, with accompanying elemental composition. The flexibility in the types of measurements the mESEM is capable of, makes it ideally suited for a variety of applications. The mESEM is appropriate for use on multiple planetary surfaces, and for a variety of mission goals (from science to non-destructive analysis to ISRU). We will identify potential applications and range of potential uses related to planetary exploration. Over the past few of years we have initiated fabrication and testing of a proof-of-concept assembly, consisting of a cold-field-emission electron gun and custom high-voltage power supply, electrostatic electron-beam focusing column, and scanning-imaging electronics plus backscatter detector. Current project status will be discussed. This effort is funded through the NASA Research Opportunities in Space and Earth Sciences - Planetary Instrument Definition and Development Program.

  19. Simulation and Characterization of a Miniaturized Scanning Electron Microscope

    Science.gov (United States)

    Gaskin, Jessica A.; Jerman, Gregory A.; Medley, Stephanie; Gregory, Don; Abbott, Terry O.; Sampson, Allen R.

    2011-01-01

    A miniaturized Scanning Electron Microscope (mSEM) for in-situ lunar investigations is being developed at NASA Marshall Space Flight Center with colleagues from the University of Alabama in Huntsville (UAH), Advanced Research Systems (ARS), the University of Tennessee in Knoxville (UTK) and Case Western Reserve University (CWRU). This effort focuses on the characterization of individual components of the mSEM and simulation of the complete system. SEMs can provide information on the size, shape, morphology and chemical composition of lunar regolith. Understanding these basic properties will allow us to better estimate the challenges associated with In-Situ Resource Utilization and to improve our basic science knowledge of the lunar surface (either precluding the need for sample return or allowing differentiation of unique samples to be returned to Earth.) The main components of the mSEM prototype includes: a cold field emission electron gun (CFEG), focusing lens, deflection/scanning system and backscatter electron detector. Of these, the electron gun development is of particular importance as it dictates much of the design of the remaining components. A CFEG was chosen for use with the lunar mSEM as its emission does not depend on heating of the tungsten emitter (lower power), it offers a long operation lifetime, is orders of magnitude brighter than tungsten hairpin guns, has a small source size and exhibits low beam energy spread.

  20. Field Emission Scanning Electron Microscope (FESEM) Facility in BTI

    International Nuclear Information System (INIS)

    Cik Rohaida Che Hak; Foo, C.T.; Nor Azillah Fatimah Othman

    2015-01-01

    Field Emission Scanning Electron Microscope (FE-SEM) provides ultra-high resolution imaging at low accelerating voltages and small working distances. The GeminisSEM 500, a new FESEM imaging facility will be installed soon in MTEC, BTI. It provides resolution of the images is as low as 0.6 nm at 15 kV and 1.2 nm at 1 kV, allowing examination of the top surface of nano powders, nano film and nano fiber in the wide range of applications such as mineralogy, ceramics, polymer, metallurgy, electronic devices, chemistry, physics and life sciences. This system is equipped with several detectors to detect various signals such as secondary electrons (SE) detector for topographic information and back-scattered electrons (BSE) detector for materials composition contrast. Energy dispersive x-ray spectroscopy (EDS) with detector energy resolution of < 129 eV and detection limit in the range of 1000-3000 ppm coupled with FE-SEM is used to determine the chemical composition of micro-features including boron (B) to uranium (U). Wavelength dispersive x-ray spectroscopy (WDS) which has detector resolution of 2-20 eV and detection limit of 30-300 ppm coupled with FE-SEM is used to detect elements that cannot be resolved with EDS. The ultra-high resolution imaging combined with the high sensitivity WDS helps to resolve the thorium and rare earth elemental analysis. (author)

  1. Microstructure of steel X 20 Cr 13 in the electron microscopical picture

    International Nuclear Information System (INIS)

    Gesatzke, W.

    1982-01-01

    The tempered microstructure of the steel X 20 Cr 13 is described by an electron microscopical overall picture and additional information is gained which would not be possible with the optical microscope. The large transmission area permits one to quantitatively evaluate a microstructure component which due to its small size can only be measured with electron microscope pictures. (orig.) [de

  2. Scanning electron microscopic evaluation of efficacy of 17% Ethylenediaminetetraacetic acid and chitosan for smear layer removal with ultrasonics: An In vitro study

    Directory of Open Access Journals (Sweden)

    Aradhana Babu Kamble

    2017-01-01

    Full Text Available Introduction: The main aim of root canal treatment is cleaning, shaping and then obturating three dimensionally to prevent reinfection. This includes chemicomechanical cleansing by instrumentation and the use of irrigating solutions. Therefore, the purpose of this study was to compare the smear layer removal from root canal dentine subjected to two root canal irrigants, 17% EDTA and 0.2% Chitosan, a new irrigant using Scanning Electron Microscope. Methodology: 40 single rooted premolars were decoronated followed by instrumentation with I Race files and intermediate irrigation with 3% sodium hypochlorite and activation with ultrasonics. Then the samples were longitudinally sectioned and place in the respective test solutions and their controls for 5 minutes. Scanning Electron Microscopic evaluation was further carried out. Results: The results of the present study indicates that the Chitosan which was proved effective in removing smear layer. Conclusion: A moderate concentration of 0.2% chitosan removes the smear layer with greater efficiency.

  3. Large area fabrication of plasmonic nanoparticle grating structure by conventional scanning electron microscope

    International Nuclear Information System (INIS)

    Sudheer,; Tiwari, P.; Rai, V. N.; Srivastava, A. K.; Mukharjee, C.

    2015-01-01

    Plasmonic nanoparticle grating (PNG) structure of different periods has been fabricated by electron beam lithography using silver halide based transmission electron microscope film as a substrate. Conventional scanning electron microscope is used as a fabrication tool for electron beam lithography. Optical microscope and energy dispersive spectroscopy (EDS) have been used for its morphological and elemental characterization. Optical characterization is performed by UV-Vis absorption spectroscopic technique

  4. Permanent magnet finger-size scanning electron microscope columns

    Energy Technology Data Exchange (ETDEWEB)

    Nelliyan, K., E-mail: elenk@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Khursheed, A. [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore)

    2011-07-21

    This paper presents permanent magnet scanning electron microscope (SEM) designs for both tungsten and field emission guns. Each column makes use of permanent magnet technology and operates at a fixed primary beam voltage. A prototype column operating at a beam voltage of 15 kV was made and tested inside the specimen chamber of a conventional SEM. A small electrostatic stigmator unit and dedicated scanning coils were integrated into the column. The scan coils were wound directly around the objective lens iron core in order to reduce its size. Preliminary experimental images of a test grid specimen were obtained through the prototype finger-size column, demonstrating that it is in principle feasible.

  5. Electron-microscope study of cloud and fog nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ogiwara, S; Okita, T

    1952-01-01

    Droplets of clouds on a mountain and of fog in an urban area were captured and the form, nature and size of their nuclei were studied by means of an electron-microscope and by a chamber of constant humidity. These nuclei have similar form and nature to the hygroscopic particles in haze and to the artificially produced combustion particles. No sea-salt nuclei were found in our observations, therefore, sea-spray appears to be an insignificant source of condensation nuclei. It was found that both the cloud and the fog nuclei originated in combustion products which were the mixture of hygroscopic and non-hygroscopic substances, and that the greater part of the nuclei did not contain pure sulfuric acid.

  6. Pigmentosis tubae, a new entity: light and electron microscopic study

    International Nuclear Information System (INIS)

    Herrera, G.A.; Reimann, B.E.; Greenberg, H.L.; Miles, P.A.

    1983-01-01

    The authors noted an unusual finding in the fallopian tubes of a 31-year-old woman who had received external and internal whole pelvis radiotherapy for squamous cell carcinoma of the cervix. Aggregates of macrophages containing pigment, identified in a subepithelial location, were reminiscent of melanosis coli, which is caused by abuse of anthracene-containing laxatives. Electron microscopic examination of the pigment revealed cytoplasmic material with the appearance of lipofuscin, identical to the pigment described in cases of colonic melanosis. After a careful study of possible etiologic agents, it was concluded that the pigment most likely resulted from cellular damage caused by radiotherapy. The authors are not aware of any other reported case of this entity, which will be called pigmentosis tubae

  7. Permanent magnet finger-size scanning electron microscope columns

    International Nuclear Information System (INIS)

    Nelliyan, K.; Khursheed, A.

    2011-01-01

    This paper presents permanent magnet scanning electron microscope (SEM) designs for both tungsten and field emission guns. Each column makes use of permanent magnet technology and operates at a fixed primary beam voltage. A prototype column operating at a beam voltage of 15 kV was made and tested inside the specimen chamber of a conventional SEM. A small electrostatic stigmator unit and dedicated scanning coils were integrated into the column. The scan coils were wound directly around the objective lens iron core in order to reduce its size. Preliminary experimental images of a test grid specimen were obtained through the prototype finger-size column, demonstrating that it is in principle feasible.

  8. Trichomes of Cannabis sativa as viewed with scanning electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Ledbetter, M C; Krikorian, A D

    1975-06-01

    Direct examination of fresh, unfixed and uncoated specimens from vegetative and floral parts of Cannabis sativa with the scanning electron microscope enables one to obtain a faithful representation of their surface morphology. The presence of two major types of trichomes has been confirmed: a glandular type comprising or terminating in a globoid structure, and a conically-shaped nonglandular type. Moreover, three or possibly four distinct glandular types can be distinguished: sessile globoid, small-stalked and large-stalked globoid, and a peltate type. The nonglandular trichomes can be distinguished by the nature of their surfaces: those with a warty surface, and those which are relatively smooth. The range of size and distribution, and the special features of all these types of trichomes are also provided.

  9. Mucopolysaccharides in the trabecular meshwork. Light and electron microscopic autoradiography

    Energy Technology Data Exchange (ETDEWEB)

    Ohnishi, Yoshitaka; Yamana, Yasuo; Abe, Masahiro (Kyushu Univ., Fukuoka (Japan). Faculty of Medicine)

    1982-09-01

    The localization of /sup 35/S-sulfate and /sup 3/H-glucosamine in the trabecular region of the hamster was studied by light and electron microscopic autoradiography after the intraperitoneal injection. Exposed silver grains of /sup 35/S-sulfate were concentrated in the trabecular meshwork, sclera and cornea, and grains of /sup 35/H-glucosamine were localized in the trabecular region. The radioactivity of both isotopes was observed in the Golgi apparatuses of the endothelial cells and fibroblasts in Schlemm's canal and the trabecular meshwork. Thereafter, the grains were noted over the entire cytoplasm, except for the nucleus, and then were incorporated into the amorphous substance and collagen fibers in the juxtacanalicular connective tissue. These results suggest that endothelial cells in the trabecular region synthesize and secrete the sulfated mucopolysaccharides and hyaluronic acid.

  10. Electron microscopic study on SrGdMnO4

    International Nuclear Information System (INIS)

    Nakano, Hiromi; Ishizawa, Nobuo; Kamegashira, Naoki; Zulhadjri; Shishido, Toetsu

    2006-01-01

    Single crystals of SrGdMnO 4 have been synthesized by the floating zone method. The structure was characterized as the K 2 NiF 4 -type, using X-ray diffraction (XRD) and a transmission electron microscope (TEM). Presence of weak reflections breaking the archetypal tetragonal symmetry was observed from the selected area diffraction (SAD). The compound was found to have an orthorhombic unit cell of a ≅ b = 0.532(4) nm, c = 1.271(6) nm, by taking the a and b axes along the diagonal directions on the basal plane of the tetragonal archetype. Structural change occurred around 1018 K. The weak reflections disappeared in the SAD pattern, suggesting that crystal is of the archetype above 1018 K

  11. Transmission electron microscope sample holder with optical features

    Science.gov (United States)

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

    2012-03-27

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

  12. In situ ion etching in a scanning electron microscope

    International Nuclear Information System (INIS)

    Dhariwal, R.S.; Fitch, R.K.

    1977-01-01

    A facility for ion etching in a scanning electron microscope is described which incorporates a new type of electrostatic ion source and viewing of the specimen is possible within about 30 sec after terminating the ion bombardment. Artefacts produced during etching have been studied and cone formation has been followed during its growth. The instrument has provided useful structural information on metals, alloys, and sinters. However, although insulating materials, such as plastics, glass and resins, have been successfully etched, interpretation of the resultant micrographs is more difficult. Ion etching of soft biological tissues, such as the rat duodenum was found to be of considerable interest. The observed structural features arise from the selective intake of the heavy fixation elements by different parts of the tissue. Hard biological materials, such as dental tissues and restorative materials, have also been studied and the prismatic structure of the enamel and the form and distribution of the dentinal tubules have been revealed. (author)

  13. A scanning electron microscopic investigation of ceramic orthodontic brackets

    International Nuclear Information System (INIS)

    McDonald, F.; Toms, A.P.

    1990-01-01

    Ceramic brackets were introduced to overcome the esthetic disadvantages of stainless steel brackets. The clinical impression of these brackets is very favorable. However, the sliding mechanics used in the Straightwire (A Company, San Diego, CA, USA) system appear to produce slower tooth movements with ceramic compared to stainless steel brackets. To determine whether this was due to any obvious mechanical problem in the bracket slot, Transcend (Unitek Corporation/3M, Monrovia, CA, USA) ceramic brackets were examined by a scanning electron microscope and compared to stainless steel brackets.Consistently, large surface defects were found in the ceramic bracket slots that were not present in the metal bracket slots. These irregularities could obviously hinder the sliding mechanics of the bracket slot-archwire system and create a greater demand on anchorage. Conversely, the fitting surface of the Transcend ceramic bracket showed extremely smooth surface characteristics, and it would seem advisable for the manufacturers to incorporate this surface within the bracket slot. (author)

  14. Characterization of polycapillary optics installed in an analytical electron microscope

    International Nuclear Information System (INIS)

    Takano, Akira; Maehata, Keisuke; Iyomoto, Naoko; Hara, Toru; Mitsuda, Kazuhisa; Yamasaki, Noriko; Tanaka, Keiichi

    2016-01-01

    An energy-dispersive spectrometer with a superconducting transition edge sensor (TES) microcalorimeter mounted on a scanning transmission electron microscope (STEM) is developed to enhance the accuracy of nanoscale materials analysis. TES microcalorimeters generally have sensitive surface areas of the order of 100 × 100 µm 2 . Also, the magnetic field generated by the STEM objective lens means that a TES microcalorimeter cannot be placed in a STEM column. We therefore use polycapillary optics to collect the X-rays. In this study, X-rays are collected from a STEM specimen and are then focused on a silicon drift detector; from these measurements, the optics are characterized and the experimental results are compared with the design of the optics. (author)

  15. Quantitative electron microscopical autoradiography of calcium during dentinogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Nagai, Y [Tokyo Dental Coll. (Japan); Frank, R M

    1975-03-01

    /sup 45/Ca migration from the dental papilla and the odontablasts towards predentin and dentin has been studied through electron microscopical autoradiography in toothgerms of newborn cats. A quantitative procedure was applied to the study of the /sup 45/Ca migration in dentinogenesis. Two pathways of almost identical importance have been demonstrated. The direct pathway followed the intercellular spaces of the dental papilla and of the odontoblasts and reached the dentin via predentin. The second road, after passage through the intercellular spaces of the dental papilla, consisted of an intracellular migration through the odontoblast. The mitochondria and the golgi apparatus were progressively the most labelet at 5 min., 30 min. and 1 h. after intravenous injection. The calcium diffused into the odontablastic process without being associated with the dense granule. At 6 hours, maximum radioactivity was observed in the intertubular dentin.

  16. Quantitative electron microscopical autoradiography of calcium during amelogenesis

    International Nuclear Information System (INIS)

    Nagai, Yoshinori; Frank, R.M.

    1975-01-01

    The migration of 45 Ca through the stratum intermedium and through the secreting ameloblasts towards enamel has been studied by electron microscopical autoradiography in the toothgerms of newborn cats. A quantitative procedure was applied to the study of the 45 Ca migration in amelogenesis and two pathways were demonstrated. The relatively more important direct route passed through the stratum intermedium and the ameloblast intercellular spaces and reached the enamel directly. The second pathway consisted of an intracellular migration through the ameloblast. 45 Ca penetrated the cell through its basal pole. The mitochondrias were the most highly labeled organelles at the different experimental time intervals studied. A total absence of silver grains was noted over the secretory ameloblastic bodies. At 6 hours, the highest labeling was observed over enamel. (auth.)

  17. Fabrication and electric measurements of nanostructures inside transmission electron microscope

    International Nuclear Information System (INIS)

    Chen, Qing; Peng, Lian-Mao

    2011-01-01

    Using manipulation holders specially designed for transmission electron microscope (TEM), nanostructures can be characterized, measured, modified and even fabricated in-situ. In-situ TEM techniques not only enable real-time study of structure-property relationships of materials at atomic scale, but also provide the ability to control and manipulate materials and structures at nanoscale. This review highlights in-situ electric measurements and in-situ fabrication and structure modification using manipulation holder inside TEM. -- Research highlights: → We review in-situ works using manipulation holder in TEM. → In-situ electric measurements, fabrication and structure modification are focused. → We discuss important issues that should be considered for reliable results. → In-situ TEM is becoming a very powerful tool for many research fields.

  18. Contained scanning electron microscope facility for examining radioactive materials

    International Nuclear Information System (INIS)

    Hsu, C.W.

    1986-03-01

    At the Savannah River Laboratory (SRL) radioactive solids are characterized with a scanning electron microscope (SEM) contained in a glove box. The system includes a research-grade Cambridge S-250 SEM, a Tracor Northern TN-5500 x-ray and image analyzer, and a Microspec wavelength-dispersive x-ray analyzer. The containment facility has a glove box train for mounting and coating samples, and for housing the SEM column, x-ray detectors, and vacuum pumps. The control consoles of the instruments are located outside the glove boxes. This facility has been actively used since October 1983 for high alpha-activity materials such as plutonium metal and plutonium oxide powders. Radioactive defense waste glasses and contaminated equipment have also been examined. During this period the facility had no safety-related incidents, and personnel radiation exposures were maintained at less than 100 mrems

  19. Structural Fingerprinting of Nanocrystals in the Transmission Electron Microscope

    Science.gov (United States)

    Rouvimov, Sergei; Plachinda, Pavel; Moeck, Peter

    2010-03-01

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

  20. Three-dimensional microbubble streaming flows

    Science.gov (United States)

    Rallabandi, Bhargav; Marin, Alvaro; Rossi, Massimiliano; Kaehler, Christian; Hilgenfeldt, Sascha

    2014-11-01

    Streaming due to acoustically excited bubbles has been used successfully for applications such as size-sorting, trapping and focusing of particles, as well as fluid mixing. Many of these applications involve the precise control of particle trajectories, typically achieved using cylindrical bubbles, which establish planar flows. Using astigmatic particle tracking velocimetry (APTV), we show that, while this two-dimensional picture is a useful description of the flow over short times, a systematic three-dimensional flow structure is evident over long time scales. We demonstrate that this long-time three-dimensional fluid motion can be understood through asymptotic theory, superimposing secondary axial flows (induced by boundary conditions at the device walls) onto the two-dimensional description. This leads to a general framework that describes three-dimensional flows in confined microstreaming systems, guiding the design of applications that profit from minimizing or maximizing these effects.

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

    Science.gov (United States)

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

    2010-06-07

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

  2. Impurity states in two - and three-dimensional disordered systems

    International Nuclear Information System (INIS)

    Silva, A.F. da; Fabbri, M.

    1984-01-01

    We investigate the microscopic structure of the impurity states in two-and three-dimensional (2D and 3d) disordered systems. A cluster model is outlined for the donor impurity density of states (DIDS) of doped semiconductors. It is shown that the impurity states are very sensitive to a change in the dimensionality of the system, i.e from 3D to 2D system. It is found that all eigenstates become localized in 2D disordered system for a large range of concentration. (Author) [pt

  3. Towards three-dimensional optical metamaterials

    Science.gov (United States)

    Tanaka, Takuo; Ishikawa, Atsushi

    2017-12-01

    Metamaterials have opened up the possibility of unprecedented and fascinating concepts and applications in optics and photonics. Examples include negative refraction, perfect lenses, cloaking, perfect absorbers, and so on. Since these metamaterials are man-made materials composed of sub-wavelength structures, their development strongly depends on the advancement of micro- and nano-fabrication technologies. In particular, the realization of three-dimensional metamaterials is one of the big challenges in this research field. In this review, we describe recent progress in the fabrication technologies for three-dimensional metamaterials, as well as proposed applications.

  4. Development of three dimensional solid modeler

    International Nuclear Information System (INIS)

    Zahoor, R.M.A.

    1999-01-01

    The work presented in this thesis is aimed at developing a three dimensional solid modeler employing computer graphics techniques using C-Language. Primitives have been generated, by combination of plane surfaces, for various basic geometrical shapes including cylinder, cube and cone. Back face removal technique for hidden surface removal has also been incorporated. Various transformation techniques such as scaling, translation, and rotation have been included for the object animation. Three dimensional solid modeler has been created by the union of two primitives to demonstrate the capabilities of the developed program. (author)

  5. Three-dimensional topological insulators and bosonization

    Energy Technology Data Exchange (ETDEWEB)

    Cappelli, Andrea [INFN, Sezione di Firenze,Via G. Sansone 1, 50019 Sesto Fiorentino - Firenze (Italy); Randellini, Enrico [INFN, Sezione di Firenze,Via G. Sansone 1, 50019 Sesto Fiorentino - Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze,Via G. Sansone 1, 50019 Sesto Fiorentino - Firenze (Italy); Sisti, Jacopo [Scuola Internazionale Superiore di Studi Avanzati (SISSA),Via Bonomea 265, 34136 Trieste (Italy)

    2017-05-25

    Massless excitations at the surface of three-dimensional time-reversal invariant topological insulators possess both fermionic and bosonic descriptions, originating from band theory and hydrodynamic BF theory, respectively. We analyze the corresponding field theories of the Dirac fermion and compactified boson and compute their partition functions on the three-dimensional torus geometry. We then find some non-dynamic exact properties of bosonization in (2+1) dimensions, regarding fermion parity and spin sectors. Using these results, we extend the Fu-Kane-Mele stability argument to fractional topological insulators in three dimensions.

  6. Three-dimensional imaging utilizing energy discrimination

    International Nuclear Information System (INIS)

    Gunter, D.L.; Hoffman, K.R.; Beck, R.N.

    1990-01-01

    An algorithm is proposed for three-dimensional image reconstruction in nuclear medicine which uses scattered radiation rather than multiple projected images to determine the source depth within the body. Images taken from numerous energy windows are combined to construct the source distribution in the body. The gamma-ray camera is not moved during the imaging process. Experiments with both Tc-99m and Ga-67 demonstrate that two channels of depth information can be extracted from the low energy images produced by scattered radiation. By combining this technique with standard SPECT reconstruction using multiple projections the authors anticipate much improved spatial resolution in the overall three-dimensional reconstruction

  7. Visualization of atomic distances at the 1MV electron microscope: first results obtained on the Grenoble 1MV microscope

    International Nuclear Information System (INIS)

    Bourret, A.

    1975-01-01

    Practical and theoretical conditions for obtaining high resolution lattice images are presented. The use of a high voltage electron microscope is particularly powerful to visualize distances smaller than 3A. A 2A resolution test on (200) gold planes has been carried out on the Grenoble 1MV microscope. It would be possible at this level to study the crystalline defects such as dislocations or grain boundaries [fr

  8. Field electron emission spectrometer combined with field ion/electron microscope as a field emission laboratory

    International Nuclear Information System (INIS)

    Shkuratov, S.I.; Ivanov, S.N.; Shilimanov, S.N.

    1996-01-01

    The facility, combining the field ion microscope, field electron emission microscope and field electron emission spectrometer, is described. Combination of three methodologies makes it possible to carry out the complete cycle of emission studies. Atom-plane and clean surface of the studied samples is prepared by means of field evaporation of the material atom layers without any thermal and radiation impact. This enables the study of atom and electron structure of clean surface of the wide range materials, the study whereof through the field emission methods was previously rather difficult. The temperature of the samples under study changes from 75 up to 2500 K. The energy resolution of the electron analyzer equals 30 MeV. 19 refs., 10 figs

  9. Ultra low-K shrinkage behavior when under electron beam in a scanning electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Lorut, F.; Imbert, G. [ST Microelectronics, 850 rue Jean Monnet, 38926 Crolles Cedex (France); Roggero, A. [Centre National d' Etudes Spatiales, 18 Avenue Edouard Belin, 31400 Toulouse (France)

    2013-08-28

    In this paper, we investigate the tendency of porous low-K dielectrics (also named Ultra Low-K, ULK) behavior to shrink when exposed to the electron beam of a scanning electron microscope. Various experimental electron beam conditions have been used for irradiating ULK thin films, and the resulting shrinkage has been measured through use of an atomic force microscope tool. We report the shrinkage to be a fast, cumulative, and dose dependent effect. Correlation of the shrinkage with incident electron beam energy loss has also been evidenced. The chemical modification of the ULK films within the interaction volume has been demonstrated, with a densification of the layer and a loss of carbon and hydrogen elements being observed.

  10. Cathodoluminescence of semiconductors in the scanning electron microscope

    International Nuclear Information System (INIS)

    Noriegas, Javier Piqueras de

    2008-01-01

    Full text: Cathodoluminescence (CL) in the scanning electron microscope (SEM) is a nondestructive technique, useful for characterization of optical and electronic properties of semiconductors, with spatial resolution. The contrast in the images of CL is related to the presence of crystalline defects, precipitates or impurities and provides information on their spatial distribution. CL spectra allows to study local energy position of localized electronic states. The application of the CL is extended to semiconductor very different characteristics, such as bulk material, heterostructures, nanocrystalline film, porous semiconductor, nanocrystals, nanowires and other nano-and microstructures. In the case of wafers, provides information on the homogeneity of their electronic characteristics, density of dislocations, grain sub frontiers, distribution of impurities and so on. while on the study of heterostructures CL images can determine, for example, the presence of misfit dislocations at the interface between different sheets, below the outer surface of the sample. In the study of other low dimensional structures, such as nanocrystalline films, nanoparticles and nano-and microstructures are observed elongated in some cases quantum confinement effects from the CL spectra. Moreover, larger structures, the order of hundreds of nanometers, with forms of wires, tubes or strips, is that in many semiconductor materials, mainly oxides, the behavior of luminescence is different from bulk material. The microstructures have a different structure of defects and a greater influence of the surface, which in some cases leads to a higher emission efficiency and a different spectral distribution. The presentation describes the principle of the CL technique and examples of its application in the characterization of a wide range of both semiconductor materials of different composition, and of different sizes ranging from nanostructures to bulk samples

  11. Three-dimensional graphene/polyaniline composite material for high-performance supercapacitor applications

    International Nuclear Information System (INIS)

    Liu, Huili; Wang, Yi; Gou, Xinglong; Qi, Tao; Yang, Jun; Ding, Yulong

    2013-01-01

    Highlights: ► A novel 3D graphene showed high specific surface area and large mesopore volume. ► Aniline monomer was polymerized in the presence of 3D graphene at room temperature. ► The supercapacitive properties were studied by CV and charge–discharge tests. ► The composite show a high gravimetric capacitance and good cyclic stability. ► The 3D graphene/polyaniline has never been report before our work. -- Abstract: A novel three-dimensional (3D) graphene/polyaniline nanocomposite material which is synthesized using in situ polymerization of aniline monomer on the graphene surface is reported as an electrode for supercapacitors. The morphology and structure of the material are characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The electrochemical properties of the resulting materials are systematically studied using cyclic voltammetry (CV) and constant current charge–discharge tests. A high gravimetric capacitance of 463 F g −1 at a scan rate of 1 mV s −1 is obtained by means of CVs with 3 mol L −1 KOH as the electrolyte. In addition, the composite material shows only 9.4% capacity loss after 500 cycles, indicating better cyclic stability for supercapacitor applications. The high specific surface area, large mesopore volume and three-dimensional nanoporous structure of 3D graphene could contribute to the high specific capacitance and good cyclic life

  12. The thermoelectric performance of bulk three-dimensional graphene

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhi, E-mail: yangzhi@tyut.edu.cn [Key Lab of Advanced Transducers and Intelligent Control System, Ministry of Education and Shanxi Province, Taiyuan University of Technology, Taiyuan 030024 (China); College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China); Lan, Guoqiang; Ouyang, Bin [Department of Mining and Materials Engineering, McGill University, Montreal H3A 0C5 (Canada); Xu, Li-Chun; Liu, Ruiping [College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China); Liu, Xuguang, E-mail: liuxuguang@tyut.edu.cn [Key Lab of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024 (China); College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Song, Jun [Department of Mining and Materials Engineering, McGill University, Montreal H3A 0C5 (Canada)

    2016-11-01

    The electronic and thermoelectric properties of a new carbon bulk material, three-dimensional (3D) graphene, are investigated in this study. Our results show that 3D graphene has unique electronic structure, i.e., near the Fermi level there exist Dirac cones. More importantly, the thermoelectric performance of 3D graphene is excellent, at room temperature the thermoelectric figure of merit (ZT) is 0.21, an order of magnitude higher than that of graphene. By introducing line defects, the ZT of 3D graphene could be enhanced to 1.52, indicating 3D graphene is a powerful candidate for constructing novel thermoelectric materials. - Highlights: • There exist Dirac cones in three-dimensional (3D) graphene. • The thermoelectric performance of 3D graphene is excellent. • The defective 3D graphene has better thermoelectric performance.

  13. Preparation of a three-dimensional extracellular matrix by decellularization of rabbit livers

    Directory of Open Access Journals (Sweden)

    Gustavo A. Nari

    2013-03-01

    Full Text Available Introduction: the availability of transplantable livers is not sufficient to fulfill the current demand for grafts, with the search for therapeutic alternatives having generated different lines of research, one of which is the use of decellularized three-dimensional biological matrices and subsequent cell seeding to obtain a functional organ. Objective: to produce a decellularization protocol from rabbit liver to generate a three-dimensional matrix. Methods: a combination of physical, chemical (Triton X-100 and SDS and enzymatic agents to decellularize rabbit livers was used. After 68 h of retrograde perfusion, a decellularized translucent matrix was generated. To evaluate if the decellularization protocol was successful, with the extracellular matrix being preserved, we carried out histological (light microscopy and scanning electron microscopy and biochemical (DNA quantification studies. Results: the decellularization process was verified by macroscopic observation of the organ using macroscopic staining, which revealed a correct conservation of bile and vascular trees. A microscopic observation corroborated these macroscopic results, with the hematoxylin-eosin staining showing no cells or nuclear material and the presence of a portal triad. Wilde's staining demonstrated the conservation of reticulin fibers in the decellularized matrix. In addition, scanning electron microscopy revealed a preserved Glisson's capsule and a decellularized matrix, with the DNA quantification being less than 10 % in the decellularized liver compared to control. Finally, the time taken to develop the decellularization protocol was less than 96 hours. Conclusions: the proposed decellularization protocol was correct, and was verified by an absence of cells. The hepatic matrix had preserved vascular and bile ducts with a suitable three-dimensional architecture permitting further cell seeding.

  14. Electron microscope investigation into dislocation structure of cast aluminium alloys

    International Nuclear Information System (INIS)

    Zolotorevskij, V.S.; Orelkina, T.A.; Istomin-Kastrovskij, V.V.

    1978-01-01

    By applying the diffraction electron microscopy method, the general specific features of the disclocation structure of cast binary alloys of aluminium with different additions were established. It is shown that in most alloys, when they undergo cooling in the process of crystallization at the rate of about 850 deg/min, the cellular dislocation structure is formed. It is shown that in all the alloys studied, the total density of dislocations of one order is about-10 9 cm -2 , which exceeds by 1 to 2 orders of magnitude the value which follows from the Tiller theory of concentration stresses. It has been experimentally established that the contribution of shrinkage and thermal stresses to the formation of a dislocation structure is rather insignificant; yet the dislocation density values calculated according to the size of dendritic cells and the medium angles of their disorientation are close to those determined by the electron-microscopic method. This is the basis for making a supposition that the greater part of the dislocations in castings are formed as a result of comparing dendritic branches with one another, which are disoriented in respect to each other

  15. Three-Dimensional Messages for Interstellar Communication

    Science.gov (United States)

    Vakoch, Douglas A.

    One of the challenges facing independently evolved civilizations separated by interstellar distances is to communicate information unique to one civilization. One commonly proposed solution is to begin with two-dimensional pictorial representations of mathematical concepts and physical objects, in the hope that this will provide a foundation for overcoming linguistic barriers. However, significant aspects of such representations are highly conventional, and may not be readily intelligible to a civilization with different conventions. The process of teaching conventions of representation may be facilitated by the use of three-dimensional representations redundantly encoded in multiple formats (e.g., as both vectors and as rasters). After having illustrated specific conventions for representing mathematical objects in a three-dimensional space, this method can be used to describe a physical environment shared by transmitter and receiver: a three-dimensional space defined by the transmitter--receiver axis, and containing stars within that space. This method can be extended to show three-dimensional representations varying over time. Having clarified conventions for representing objects potentially familiar to both sender and receiver, novel objects can subsequently be depicted. This is illustrated through sequences showing interactions between human beings, which provide information about human behavior and personality. Extensions of this method may allow the communication of such culture-specific features as aesthetic judgments and religious beliefs. Limitations of this approach will be noted, with specific reference to ETI who are not primarily visual.

  16. Three-Dimensional Printing Surgical Applications.

    Science.gov (United States)

    AlAli, Ahmad B; Griffin, Michelle F; Butler, Peter E

    2015-01-01

    Three-dimensional printing, a technology used for decades in the industrial field, gains a lot of attention in the medical field for its potential benefits. With advancement of desktop printers, this technology is accessible and a lot of research is going on in the medical field. To evaluate its application in surgical field, which may include but not limited to surgical planning, surgical education, implants, and prosthesis, which are the focus of this review. Research was conducted by searching PubMed, Web of science, and other reliable sources. We included original articles and excluded articles based on animals, those more than 10 years old, and those not in English. These articles were evaluated, and relevant studies were included in this review. Three-dimensional printing shows a potential benefit in surgical application. Printed implants were used in patient in a few cases and show successful results; however, longer follow-up and more trials are needed. Surgical and medical education is believed to be more efficient with this technology than the current practice. Printed surgical instrument and surgical planning are also believed to improve with three-dimensional printing. Three-dimensional printing can be a very powerful tool in the near future, which can aid the medical field that is facing a lot of challenges and obstacles. However, despite the reported results, further research on larger samples and analytical measurements should be conducted to ensure this technology's impact on the practice.

  17. Three dimensional electrochemical system for neurobiological studies

    DEFF Research Database (Denmark)

    Vazquez, Patricia; Dimaki, Maria; Svendsen, Winnie Edith

    2009-01-01

    In this work we report a novel three dimensional electrode array for electrochemical measurements in neuronal studies. The main advantage of working with these out-of-plane structures is the enhanced sensitivity of the system in terms of measuring electrochemical changes in the environment...

  18. Imaging unsteady three-dimensional transport phenomena

    Indian Academy of Sciences (India)

    2014-01-05

    Jan 5, 2014 ... The image data can be jointly analysed with the physical laws governing transport and principles of image formation. Hence, with the experiment suitably carried out, three-dimensional physical domains with unsteady processes can be accommodated. Optical methods promise to breach the holy grail of ...

  19. Computerized three-dimensional normal atlas

    International Nuclear Information System (INIS)

    Mano, Isamu; Suto, Yasuzo; Suzuki, Masataka; Iio, Masahiro.

    1990-01-01

    This paper presents our ongoing project in which normal human anatomy and its quantitative data are systematically arranged in a computer. The final product, the Computerized Three-Dimensional Normal Atlas, will be able to supply tomographic images in any direction, 3-D images, and coded information on organs, e.g., anatomical names, CT numbers, and T 1 and T 2 values. (author)

  20. Three-Dimensional Shallow Water Acoustics

    Science.gov (United States)

    2016-03-30

    medium properties, so horizontal refraction and reflection of sound can occur and produce significant three-dimensional (3-D) sound propagation ...by the environmental factors existing commonly in the continental shelf and shelfbreak areas, such as slopes, submarine canyons, sub-bottom layers ...surface waves, internal waves and shelfbreak fronts. 15. SUBJECT TERMS Continental Shelf; 3-D Acoustics , Surface Waves, Sound Propagation 16

  1. A distributed multi-GPU system for high speed electron microscopic tomographic reconstruction.

    Science.gov (United States)

    Zheng, Shawn Q; Branlund, Eric; Kesthelyi, Bettina; Braunfeld, Michael B; Cheng, Yifan; Sedat, John W; Agard, David A

    2011-07-01

    Full resolution electron microscopic tomographic (EMT) reconstruction of large-scale tilt series requires significant computing power. The desire to perform multiple cycles of iterative reconstruction and realignment dramatically increases the pressing need to improve reconstruction performance. This has motivated us to develop a distributed multi-GPU (graphics processing unit) system to provide the required computing power for rapid constrained, iterative reconstructions of very large three-dimensional (3D) volumes. The participating GPUs reconstruct segments of the volume in parallel, and subsequently, the segments are assembled to form the complete 3D volume. Owing to its power and versatility, the CUDA (NVIDIA, USA) platform was selected for GPU implementation of the EMT reconstruction. For a system containing 10 GPUs provided by 5 GTX295 cards, 10 cycles of SIRT reconstruction for a tomogram of 4096(2) × 512 voxels from an input tilt series containing 122 projection images of 4096(2) pixels (single precision float) takes a total of 1845 s of which 1032 s are for computation with the remainder being the system overhead. The same system takes only 39 s total to reconstruct 1024(2) × 256 voxels from 122 1024(2) pixel projections. While the system overhead is non-trivial, performance analysis indicates that adding extra GPUs to the system would lead to steadily enhanced overall performance. Therefore, this system can be easily expanded to generate superior computing power for very large tomographic reconstructions and especially to empower iterative cycles of reconstruction and realignment. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Advances in imaging and electron physics the scanning transmission electron microscope

    CERN Document Server

    Hawkes, Peter W

    2009-01-01

    Advances in Imaging and Electron Physics merges two long-running serials--Advances in Electronics and Electron Physics and Advances in Optical and Electron Microscopy. This series features extended articles on the physics of electron devices (especially semiconductor devices), particle optics at high and low energies, microlithography, image science and digital image processing, electromagnetic wave propagation, electron microscopy, and the computing methods used in all these domains.  This particular volume presents several timely articles on the scanning transmission electron microscope. Updated with contributions from leading international scholars and industry experts Discusses hot topic areas and presents current and future research trends Provides an invaluable reference and guide for physicists, engineers and mathematicians.

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

    Science.gov (United States)

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

    2014-12-01

    Transmission electron microscope (TEM) observation of light metal hydrides is complicated by the instability of these materials under electron irradiation. In this study, the electron kinetic energy dependences of the interactions of incident electrons with lithium, sodium and magnesium hydrides, as well as the constituting element effect on the interactions, were theoretically discussed, and electron irradiation damage to these hydrides was examined using in situ TEM. The results indicate that high incident electron kinetic energy helps alleviate the irradiation damage resulting from inelastic or elastic scattering of the incident electrons in the TEM. Therefore, observations and characterizations of these materials would benefit from increased, instead decreased, TEM operating voltage. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Detailed optical characterization of three-dimensional visible-frequency polarization-independent carpet invisibility cloak

    International Nuclear Information System (INIS)

    Ergin, Tolga; Fischer, Joachim; Wegener, Martin

    2012-01-01

    The invention of the three-dimensional woodpile photonic crystal by Costas M. Soukoulis and coworkers in 1994 has stimulated much further research - excellent research stimulates further research. Here, we report on using spatially inhomogeneous polymer woodpile structures in the long-wavelength limit as artificial graded-index structures. After briefly reviewing previous work on carpet invisibility cloaks designed by transformation optics, we present new experiments for various focus planes of the inspecting microscope as well as for different inspection angles in three-dimensional space. Numerical ray-tracing modeling is also provided. These data confirm our previous assessment that three-dimensional cloaking is quite robust for these structures.

  5. Three-dimensional fractional topological insulators in coupled Rashba layers

    Science.gov (United States)

    Volpez, Yanick; Loss, Daniel; Klinovaja, Jelena

    2017-08-01

    We propose a model of three-dimensional topological insulators consisting of weakly coupled electron- and hole-gas layers with Rashba spin-orbit interaction stacked along a given axis. We show that in the presence of strong electron-electron interactions the system realizes a fractional strong topological insulator, where the rotational symmetry and condensation energy arguments still allow us to treat the problem as quasi-one-dimensional with bosonization techniques. We also show that if Rashba and Dresselhaus spin-orbit interaction terms are equally strong, by doping the system with magnetic impurities, one can bring it into the Weyl semimetal phase.

  6. Problems of high temperature superconductivity in three-dimensional systems

    Energy Technology Data Exchange (ETDEWEB)

    Geilikman, B T

    1973-01-01

    A review is given of more recent papers on this subject. These papers have dealt mainly with two-dimensional systems. The present paper extends the treatment to three-dimensional systems, under the following headings: systems with collective electrons of one group and localized electrons of another group (compounds of metals with non-metals-dielectrics, organic substances, undoped semiconductors, molecular crystals); experimental investigations of superconducting compounds of metals with organic compounds, dielectrics, semiconductors, and semi-metals; and systems with two or more groups of collective electrons. Mechanics are considered and models are derived. 86 references.

  7. Collaborative Research and Development. Delivery Order 0006: Transmission Electron Microscope Image Modeling and Semiconductor Heterointerface Characterization

    National Research Council Canada - National Science Library

    Mahalingam, Krishnamurthy

    2006-01-01

    .... Transmission electron microscope (TEM) characterization studies were performed on a variety of novel III-V semiconductor heterostructures being developed for advanced optoelectronic device applications...

  8. Electron sputtering in the analytical electron microscope: Calculations and experimental data

    International Nuclear Information System (INIS)

    Zaluzec, N.J.; Mansfield, J.F.

    1987-03-01

    The environment of the electron microscope is particularly severe when one considers the energy deposited in a specimen during typical experimental conditions. Conventional imaging experiments tend to employ electron current densities ranging from ∼0.1 to 1 A/cm 2 while during microanalysis conditions probe current densities can range from 10 to values as high as 10 5 A/cm 2 . At 100 kV this corresponds to power densities from 100 Kilowatts/cm 2 to 10 4 Megawatts/cm 2 . These energy deposition rates can result in electron irradiation damage which can substantially alter the structure and composition of a specimen through either ionization damage in organics or by displacement damage in inorganics and/or combinations thereof. For the most part materials scientists operating an analytical electron microscope (AEM) in the 100 to 200 kV regime studying metallic and/or ceramic specimens have been spared the need to consider either of these effects as their specimens have tended to be sufficiently resilient. However, the advent of the new medium voltage microscopes operating in the 300 to 400 kV regime with high brightness guns and clean or ultrahigh vacuum systems has necessitated a reevaluation of the effects of higher voltage operation in light of the destructive nature of the electron beam particularly under microanalysis conditions

  9. Microscopic appearance analysis of raw material used for the production of sintered UO2 by scanning electron microscope

    International Nuclear Information System (INIS)

    Liu feiming

    1992-01-01

    The paper describes the microscopic appearance of UO 2 , U 3 O 8 , ADU and AUC powders used for the production of sintered UO 2 slug of nuclear fuel component of PWR. The characteristic analysis of the microscopic appearance observed by scanning electron microscope shows that the quality and finished product rate of sintered UO 2 depend on the appearance characteristic of the active Uo 2 powder, such as grade size and its distribution, spherulitized extent, surface condition and heap model etc.. The addition of U 3 O 8 to the UO 2 powder improves significantly the quality and the finished product rate. The mechanism of this effect is discussed on the basis of the microscopic appearance characteristic for two kinds of powder

  10. Electron Source Brightness and Illumination Semi-Angle Distribution Measurement in a Transmission Electron Microscope.

    Science.gov (United States)

    Börrnert, Felix; Renner, Julian; Kaiser, Ute

    2018-05-21

    The electron source brightness is an important parameter in an electron microscope. Reliable and easy brightness measurement routes are not easily found. A determination method for the illumination semi-angle distribution in transmission electron microscopy is even less well documented. Herein, we report a simple measurement route for both entities and demonstrate it on a state-of-the-art instrument. The reduced axial brightness of the FEI X-FEG with a monochromator was determined to be larger than 108 A/(m2 sr V).

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

    Science.gov (United States)

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

    2015-08-01

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

  12. Wide-range tunable magnetic lens for tabletop electron microscope

    International Nuclear Information System (INIS)

    Chang, Wei-Yu; Chen, Fu-Rong

    2016-01-01

    A tabletop scanning electron microscope (SEM) utilizes permanent magnets as condenser lenses to minimize its size, but this sacrifices the tunability of condenser lenses such that a tabletop system can only be operated with a fixed accelerating voltage. In contrast, the traditional condenser lens utilizes an electromagnetic coil to adjust the optical properties, but the size of the electromagnetic lens is inevitably larger. Here, we propose a tunable condenser lens for a tabletop SEM that uses a combination of permanent magnets and electromagnetic coils. The overall dimensions of the newly designed lens are the same as the original permanent magnet lens, but the new lens allows the tabletop SEM to be operated at different accelerating voltages between 1 kV and 15 kV. - Highlights: • A compact condenser lens combines both permanent magnet and coils. • A tunable lens is designed to keep the same focal point for voltage 1 to 15 kV. • A miniature tunable lens which can directly fit into tabletop SEM.

  13. Contact detection for nanomanipulation in a scanning electron microscope.

    Science.gov (United States)

    Ru, Changhai; To, Steve

    2012-07-01

    Nanomanipulation systems require accurate knowledge of the end-effector position in all three spatial coordinates, XYZ, for reliable manipulation of nanostructures. Although the images acquired by a scanning electron microscope (SEM) provide high resolution XY information, the lack of depth information in the Z-direction makes 3D nanomanipulation time-consuming. Existing approaches for contact detection of end-effectors inside SEM typically utilize fragile touch sensors that are difficult to integrate into a nanomanipulation system. This paper presents a method for determining the contact between an end-effector and a target surface during nanomanipulation inside SEM, purely based on the processing of SEM images. A depth-from-focus method is used in the fast approach of the end-effector to the substrate, followed by fine contact detection. Experimental results demonstrate that the contact detection approach is capable of achieving an accuracy of 21.5 nm at 50,000× magnification while inducing little end-effector damage. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. AIMgSil Alloy Characterization Using Transmission Electron Microscope (TEM)

    International Nuclear Information System (INIS)

    Masrukan; Elman, P.

    1996-01-01

    The aging alloy of AIMgSil containing Mg 2 Si of 1.29 % has been done with the following steps: e.q (a) part of the specimen was heated at 400 o C during 3 hours, and (b) the other part was done with solution treatment at 550 o C followed by quenching. After quenching a part of the specimen was aged at room temperature and other specimen was aged at 160 o C during 16 hours. After the specimen had been heated, then it was shaped into thin foil to be examined by Transmission Electron Microscope. The result showed that the heating at temperature of 400 o C during 3 hours created a second phase (i.e.Mg 2 Si) was like stick shape with the hexagonal structure at [0111] orientation and matrix [001], and the hardness was 31 HB. The aging of specimen at room temperature gave result a GP zone which was like the needles shape in the dislocation area of the face center cubic structure at [111] orientation and [111] matrix. The hardness obtained was 64 HB. In the other hand the aging process at temperature of 160 o C within 16 hours have resulted the precipitate which was greater than that of the former needle shaped as the face center cubic structure without dislocation at matrix with [111] orientation and [114] matrix. The hardness at this condition was 94 HB

  15. Radioactive and electron microscope analysis of effluent monitor sample lines

    International Nuclear Information System (INIS)

    Kowalski, J.F.

    1986-01-01

    Effluent air sampling at nuclear power plant often leads to the question ''How representative is the sample of the effluent stream?'' Samples from radiation monitors are typically obtained at great distances from the sample nozzle because of high background concerns under postulated accidents. Sample line plateout during normal effluent sampling becomes the major concern. A US Nuclear Regulatory Commission inspection raised a concern that monitors were not collecting representative samples per ANSI standard N13.1. A comprehensive 2-yr study at Beaver Valley was performed during normal effluent releases in two phases: 1) weekly charcoal and glass fiber filter samples were analyzed for radioactivity for 6 months, and 2) nuclepore membrane filter samples were analyzed by electron microscope for 4- and 6-h periods. A specially designed test nozzle was directly inserted into an effluent stream for comparison with the radiation monitor samples. Particle behavior characteristics can be determined during effluent releases using a simple test probe. While particle plateout was the major purpose of the study, other particle behavior characteristics were evident and equally as important. Particle travel through long sample lines can also lead to (a) agglomeration or the coagulation of smaller particles to form larger ones, (b) particle splitting or fracturing upon impact with the sample line interior walls, and (c) resuspension of large particles in sample lines

  16. Contact detection for nanomanipulation in a scanning electron microscope

    International Nuclear Information System (INIS)

    Ru, Changhai; To, Steve

    2012-01-01

    Nanomanipulation systems require accurate knowledge of the end-effector position in all three spatial coordinates, XYZ, for reliable manipulation of nanostructures. Although the images acquired by a scanning electron microscope (SEM) provide high resolution XY information, the lack of depth information in the Z-direction makes 3D nanomanipulation time-consuming. Existing approaches for contact detection of end-effectors inside SEM typically utilize fragile touch sensors that are difficult to integrate into a nanomanipulation system. This paper presents a method for determining the contact between an end-effector and a target surface during nanomanipulation inside SEM, purely based on the processing of SEM images. A depth-from-focus method is used in the fast approach of the end-effector to the substrate, followed by fine contact detection. Experimental results demonstrate that the contact detection approach is capable of achieving an accuracy of 21.5 nm at 50,000× magnification while inducing little end-effector damage. -- Highlights: ► We presents a simple method for obtaining the depth information in SEM-based nanomanipulation. ► Detecting contact between an end-effector and a target surface using SEM as a vision sensor. ► Additional touch/force sensors or specialized hardware need not be added. ► Achieved high repeatability and accuracy. ► Complete automatic contact detection within typically 60 s.

  17. Wide-range tunable magnetic lens for tabletop electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Wei-Yu; Chen, Fu-Rong, E-mail: fchen1@me.com

    2016-12-15

    A tabletop scanning electron microscope (SEM) utilizes permanent magnets as condenser lenses to minimize its size, but this sacrifices the tunability of condenser lenses such that a tabletop system can only be operated with a fixed accelerating voltage. In contrast, the traditional condenser lens utilizes an electromagnetic coil to adjust the optical properties, but the size of the electromagnetic lens is inevitably larger. Here, we propose a tunable condenser lens for a tabletop SEM that uses a combination of permanent magnets and electromagnetic coils. The overall dimensions of the newly designed lens are the same as the original permanent magnet lens, but the new lens allows the tabletop SEM to be operated at different accelerating voltages between 1 kV and 15 kV. - Highlights: • A compact condenser lens combines both permanent magnet and coils. • A tunable lens is designed to keep the same focal point for voltage 1 to 15 kV. • A miniature tunable lens which can directly fit into tabletop SEM.

  18. Somatic Embryos in Catharanthus roseus: A Scanning Electron Microscopic Study

    Directory of Open Access Journals (Sweden)

    Junaid ASLAM

    2014-06-01

    Full Text Available Catharanthus roseus (L. G. Don is an important medicinal plant as it contains several anti-cancerous compounds, like vinblastine and vincristine. Plant tissue culture technology (organogenesis and embryogenesis has currently been used in fast mass propagating raw materials for secondary metabolite synthesis. In this present communication, scanning electron microscopic (SEM study of somatic embryos was conducted and discussed. The embryogenic callus was first induced from hypocotyls of in vitro germinated seeds on which somatic embryos, differentiated in numbers, particularly on 2,4-D (1.0 mg/L Murashige and Skoog (MS was medium. To understand more about the regeneration method and in vitro formed embryos SEM was performed. The SEM study revealed normal somatic embryo origin and development from globular to heart-, torpedo- and then into cotyledonary-stage of embryos. At early stage, the embryos were clustered together in a callus mass and could not easily be detached from the parental tissue. The embryos were often long cylindrical structure with or without typical notch at the tip. Secondary embryos were also formed on primary embryo structure. The advanced cotyledonary embryos showed prominent roots and shoot axis, which germinated into plantlets. The morphology, structure and other details of somatic embryos at various stages were presented.

  19. Contact detection for nanomanipulation in a scanning electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Ru, Changhai, E-mail: rchhai@gmail.com [Automation College, Harbin Engineering University, Harbin 150001 (China); Robotics and Microsystems Center, Soochow University, Jiangsu 215021 (China); To, Steve, E-mail: Steve.to@utoronto.ca [Department of Mechanical and Industry Engineering, University of Toronto, Ontario, Canada M5S3G8 (Canada)

    2012-07-15

    Nanomanipulation systems require accurate knowledge of the end-effector position in all three spatial coordinates, XYZ, for reliable manipulation of nanostructures. Although the images acquired by a scanning electron microscope (SEM) provide high resolution XY information, the lack of depth information in the Z-direction makes 3D nanomanipulation time-consuming. Existing approaches for contact detection of end-effectors inside SEM typically utilize fragile touch sensors that are difficult to integrate into a nanomanipulation system. This paper presents a method for determining the contact between an end-effector and a target surface during nanomanipulation inside SEM, purely based on the processing of SEM images. A depth-from-focus method is used in the fast approach of the end-effector to the substrate, followed by fine contact detection. Experimental results demonstrate that the contact detection approach is capable of achieving an accuracy of 21.5 nm at 50,000 Multiplication-Sign magnification while inducing little end-effector damage. -- Highlights: Black-Right-Pointing-Pointer We presents a simple method for obtaining the depth information in SEM-based nanomanipulation. Black-Right-Pointing-Pointer Detecting contact between an end-effector and a target surface using SEM as a vision sensor. Black-Right-Pointing-Pointer Additional touch/force sensors or specialized hardware need not be added. Black-Right-Pointing-Pointer Achieved high repeatability and accuracy. Black-Right-Pointing-Pointer Complete automatic contact detection within typically 60 s.

  20. Electron beam dynamics in an ultrafast transmission electron microscope with Wehnelt electrode.

    Science.gov (United States)

    Bücker, K; Picher, M; Crégut, O; LaGrange, T; Reed, B W; Park, S T; Masiel, D J; Banhart, F

    2016-12-01

    High temporal resolution transmission electron microscopy techniques have shown significant progress in recent years. Using photoelectron pulses induced by ultrashort laser pulses on the cathode, these methods can probe ultrafast materials processes and have revealed numerous dynamic phenomena at the nanoscale. Most recently, the technique has been implemented in standard thermionic electron microscopes that provide a flexible platform for studying material's dynamics over a wide range of spatial and temporal scales. In this study, the electron pulses in such an ultrafast transmission electron microscope are characterized in detail. The microscope is based on a thermionic gun with a Wehnelt electrode and is operated in a stroboscopic photoelectron mode. It is shown that the Wehnelt bias has a decisive influence on the temporal and energy spread of the picosecond electron pulses. Depending on the shape of the cathode and the cathode-Wehnelt distance, different emission patterns with different pulse parameters are obtained. The energy spread of the pulses is determined by space charge and Boersch effects, given by the number of electrons in a pulse. However, filtering effects due to the chromatic aberrations of the Wehnelt electrode allow the extraction of pulses with narrow energy spreads. The temporal spread is governed by electron trajectories of different length and in different electrostatic potentials. High temporal resolution is obtained by excluding shank emission from the cathode and aberration-induced halos in the emission pattern. By varying the cathode-Wehnelt gap, the Wehnelt bias, and the number of photoelectrons in a pulse, tradeoffs between energy and temporal resolution as well as beam intensity can be made as needed for experiments. Based on the characterization of the electron pulses, the optimal conditions for the operation of ultrafast TEMs with thermionic gun assembly are elaborated. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. High resolution x-ray stereomicroscopy: True three-dimensional imaging of biological samples

    International Nuclear Information System (INIS)

    Loo, B.W.Jr.; Williams, S.; Meizel, S.; Rothman, S.S.; Univ. of California, Berkeley/San Francisco, CA; Univ. of California, San Francisco, CA

    1993-01-01

    X-ray microscopy has the potential to become a powerful tool for the study of biological samples, allowing the imaging of intact cells and subcellular organelles in an aqueous environment at resolutions previously achievable only by electron microscopy. The ability to examine a relatively thick sample raises the issue of superposition of objects from multiple planes within the sample, making difficult the interpretation of conventional, orthogonally projected images. This paper describes early attempts at developing three-dimensional methods for x-ray microimaging: the first to use x-ray optics, and to the authors' knowledge, the first demonstrating sub-visible resolutions and natural contrast. These studies were performed using the scanning transmission x-ray microscope (STXM) at the National Synchrotron Light Source, Brookhaven National Laboratory

  2. Automated three-dimensional X-ray analysis using a dual-beam FIB

    International Nuclear Information System (INIS)

    Schaffer, Miroslava; Wagner, Julian; Schaffer, Bernhard; Schmied, Mario; Mulders, Hans

    2007-01-01

    We present a fully automated method for three-dimensional (3D) elemental analysis demonstrated using a ceramic sample of chemistry (Ca)MgTiO x . The specimen is serially sectioned by a focused ion beam (FIB) microscope, and energy-dispersive X-ray spectrometry (EDXS) is used for elemental analysis of each cross-section created. A 3D elemental model is reconstructed from the stack of two-dimensional (2D) data. This work concentrates on issues arising from process automation, the large sample volume of approximately 17x17x10 μm 3 , and the insulating nature of the specimen. A new routine for post-acquisition data correction of different drift effects is demonstrated. Furthermore, it is shown that EDXS data may be erroneous for specimens containing voids, and that back-scattered electron images have to be used to correct for these errors

  3. Arching in three-dimensional clogging

    Science.gov (United States)

    Török, János; Lévay, Sára; Szabó, Balázs; Somfai, Ellák; Wegner, Sandra; Stannarius, Ralf; Börzsönyi, Tamás

    2017-06-01

    Arching in dry granular material is a long established concept, however it remains still an open question how three-dimensional orifices clog. We investigate by means of numerical simulations and experimental data how the outflow creates a blocked configuration of particles. We define the concave surface of the clogged dome by two independent methods (geometric and density based). The average shape of the cupola for spheres is almost a hemisphere but individual samples have large holes in the structure indicating a blocked state composed of two-dimensional force chains rather than three-dimensional objects. The force chain structure justifies this assumption. For long particles the clogged configurations display large variations, and in certain cases the empty region reaches a height of 5 hole diameters. These structures involve vertical walls consisting of horizontally placed stable stacking of particles.

  4. Three-dimensional bio-printing.

    Science.gov (United States)

    Gu, Qi; Hao, Jie; Lu, YangJie; Wang, Liu; Wallace, Gordon G; Zhou, Qi

    2015-05-01

    Three-dimensional (3D) printing technology has been widely used in various manufacturing operations including automotive, defence and space industries. 3D printing has the advantages of personalization, flexibility and high resolution, and is therefore becoming increasingly visible in the high-tech fields. Three-dimensional bio-printing technology also holds promise for future use in medical applications. At present 3D bio-printing is mainly used for simulating and reconstructing some hard tissues or for preparing drug-delivery systems in the medical area. The fabrication of 3D structures with living cells and bioactive moieties spatially distributed throughout will be realisable. Fabrication of complex tissues and organs is still at the exploratory stage. This review summarize the development of 3D bio-printing and its potential in medical applications, as well as discussing the current challenges faced by 3D bio-printing.

  5. Three dimensional imaging in cardiac nuclear medicine

    International Nuclear Information System (INIS)

    Torizuka, Kanji; Ishii, Yasushi; Yonekura, Yoshiharu; Yamamoto, Kazutaka; Tamaki, Takeyoshi

    1981-01-01

    Methods to obtain three dimensional images of the heart were reviewed. Gated three dimensional display reconstructed from images using bidirectional collimator, was a useful method to detect akinesis of the heart wall. Tomographic observation of the heart can be carried out by a pinhole collimator to image ischemia with high sensitivity. However the focusing plane must be carefully selected to prevent false positives. In the case of emission CT (ECT), utilization of positron emitters gave a quantitative image without correction, whereas single photon ECT needed the correction due to the absorption of γ-ray. Though the reliability of the images by ECT was high, the time required for data acquisition was much longer than that by a 7 pinhole or bidirectional collimator. (Nakanishi, T.)

  6. Three dimensional transport model for toroidal plasmas

    International Nuclear Information System (INIS)

    Copenhauer, C.

    1980-12-01

    A nonlinear MHD model, developed for three-dimensional toroidal geometries (asymmetric) and for high β (β approximately epsilon), is used as a basis for a three-dimensional transport model. Since inertia terms are needed in describing evolving magnetic islands, the model can calculate transport, both in the transient phase before nonlinear saturation of magnetic islands and afterwards on the resistive time scale. In the β approximately epsilon ordering, the plasma does not have sufficient energy to compress the parallel magnetic field, which allows the Alfven wave to be eliminated in the reduced nonlinear equations, and the model then follows the slower time scales. The resulting perpendicular and parallel plasma drift velocities can be identified with those of guiding center theory

  7. Three dimensional digital imaging of environmental data

    International Nuclear Information System (INIS)

    Nichols, R.L.; Eddy, C.A.

    1991-01-01

    The Environmental Sciences Section (ESS) of the Savannah River Laboratory has recently acquired the computer hardware (Silicon Graphics Personal Iris Workstations) and software (Dynamic Graphics, Interactive Surface and Volume Modeling) to perform three dimensional analysis of hydrogeologic data. Three dimensional digital imaging of environmental data is a powerful technique that can be used to incorporate field, analytical, and modeling results from geologic, hydrologic, ecologic, and chemical studies into a comprehensive model for visualization and interpretation. This report covers the contamination of four different sites of the Savannah River Plant. Each section of this report has a computer graphic display of the concentration of contamination in the groundwater and/or sediments of each site

  8. SNAP - a three dimensional neutron diffusion code

    International Nuclear Information System (INIS)

    McCallien, C.W.J.

    1993-02-01

    This report describes a one- two- three-dimensional multi-group diffusion code, SNAP, which is primarily intended for neutron diffusion calculations but can also carry out gamma calculations if the diffusion approximation is accurate enough. It is suitable for fast and thermal reactor core calculations and for shield calculations. SNAP can solve the multi-group neutron diffusion equations using finite difference methods. The one-dimensional slab, cylindrical and spherical geometries and the two-dimensional case are all treated as simple special cases of three-dimensional geometries. Numerous reflective and periodic symmetry options are available and may be used to reduce the number of mesh points necessary to represent the system. Extrapolation lengths can be specified at internal and external boundaries. (Author)

  9. Three-dimensional imaging modalities in endodontics

    Science.gov (United States)

    Mao, Teresa

    2014-01-01

    Recent research in endodontics has highlighted the need for three-dimensional imaging in the clinical arena as well as in research. Three-dimensional imaging using computed tomography (CT) has been used in endodontics over the past decade. Three types of CT scans have been studied in endodontics, namely cone-beam CT, spiral CT, and peripheral quantitative CT. Contemporary endodontics places an emphasis on the use of cone-beam CT for an accurate diagnosis of parameters that cannot be visualized on a two-dimensional image. This review discusses the role of CT in endodontics, pertaining to its importance in the diagnosis of root canal anatomy, detection of peri-radicular lesions, diagnosis of trauma and resorption, presurgical assessment, and evaluation of the treatment outcome. PMID:25279337

  10. Three-dimensional imaging modalities in endodontics

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Teresa; Neelakantan, Prasanna [Dept. of Conservative Dentistry and Endodontics, Saveetha Dental College and Hospitals, Saveetha University, Chennai (India)

    2014-09-15

    Recent research in endodontics has highlighted the need for three-dimensional imaging in the clinical arena as well as in research. Three-dimensional imaging using computed tomography (CT) has been used in endodontics over the past decade. Three types of CT scans have been studied in endodontics, namely cone-beam CT, spiral CT, and peripheral quantitative CT. Contemporary endodontics places an emphasis on the use of cone-beam CT for an accurate diagnosis of parameters that cannot be visualized on a two-dimensional image. This review discusses the role of CT in endodontics, pertaining to its importance in the diagnosis of root canal anatomy, detection of peri-radicular lesions, diagnosis of trauma and resorption, presurgical assessment, and evaluation of the treatment outcome.

  11. Three-dimensional imaging modalities in endodontics

    International Nuclear Information System (INIS)

    Mao, Teresa; Neelakantan, Prasanna

    2014-01-01

    Recent research in endodontics has highlighted the need for three-dimensional imaging in the clinical arena as well as in research. Three-dimensional imaging using computed tomography (CT) has been used in endodontics over the past decade. Three types of CT scans have been studied in endodontics, namely cone-beam CT, spiral CT, and peripheral quantitative CT. Contemporary endodontics places an emphasis on the use of cone-beam CT for an accurate diagnosis of parameters that cannot be visualized on a two-dimensional image. This review discusses the role of CT in endodontics, pertaining to its importance in the diagnosis of root canal anatomy, detection of peri-radicular lesions, diagnosis of trauma and resorption, presurgical assessment, and evaluation of the treatment outcome

  12. THREE DIMENSIONAL GRAPHICAL REPRESENTATION OF QUALITY

    Directory of Open Access Journals (Sweden)

    Vineet V. Kumar

    2014-03-01

    Full Text Available Quality is an important aspect for every firm in modern era of competition. Every product has tough competition in terms of market reach. The factor, which actually makes any product long run in market, is quality and hence quality is the stepping-stone for success of any firm. For everyone meaning of quality is different. We have seen several economists who have defined quality by considering different factors, but what all of them have common in them is Customer satisfaction. Customer satisfaction is the ultimate result of quality. In three-dimensional graphical representation of quality, optimum quality is obtained by using three-dimensional graph by considering some important factors governing quality of any product, limiting factor, and customer satisfaction.

  13. Three dimensional contact/impact methodology

    International Nuclear Information System (INIS)

    Kulak, R.F.

    1987-01-01

    The simulation of three-dimensional interface mechanics between reactor components and structures during static contact or dynamic impact is necessary to realistically evaluate their structural integrity to off-normal loads. In our studies of postulated core energy release events, we have found that significant structure-structure interactions occur in some reactor vessel head closure designs and that fluid-structure interactions occur within the reactor vessel. Other examples in which three-dimensional interface mechanics play an important role are: (1) impact response of shipping casks containing spent fuel, (2) whipping pipe impact on reinforced concrete panels or pipe-to-pipe impact after a pipe break, (3) aircraft crash on secondary containment structures, (4) missiles generated by turbine failures or tornados, and (5) drops of heavy components due to lifting accidents. The above is a partial list of reactor safety problems that require adequate treatment of interface mechanics and are discussed in this paper

  14. Three-dimensional simulation of vortex breakdown

    Science.gov (United States)

    Kuruvila, G.; Salas, M. D.

    1990-01-01

    The integral form of the complete, unsteady, compressible, three-dimensional Navier-Stokes equations in the conservation form, cast in generalized coordinate system, are solved, numerically, to simulate the vortex breakdown phenomenon. The inviscid fluxes are discretized using Roe's upwind-biased flux-difference splitting scheme and the viscous fluxes are discretized using central differencing. Time integration is performed using a backward Euler ADI (alternating direction implicit) scheme. A full approximation multigrid is used to accelerate the convergence to steady state.

  15. Impermeability effects in three-dimensional vesicles

    International Nuclear Information System (INIS)

    Biscari, P; Canevese, S M; Napoli, G

    2004-01-01

    We analyse the effects of the impermeability constraint on the equilibrium shapes of a three-dimensional vesicle hosting a rigid inclusion. A given alteration of the inclusion and/or vesicle parameters leads to shape modifications of different orders of magnitude, when applied to permeable or impermeable vesicles. Moreover, the enclosed-volume constraint wrecks the uniqueness of stationary equilibrium shapes, and gives rise to pear-shaped or stomatocyte-like vesicles

  16. The impact of irradiation induced specimen charging on microanalysis in a scanning electron microscope

    International Nuclear Information System (INIS)

    Stevens-Kalceff, M.A.

    2003-01-01

    subsurface specimen charging may still be significant. Charged beam irradiation of poorly conducting materials results in the trapping of charge at pre-existing or irradiation induced defects thereby inducing a localized electric field within the irradiated micro-volume of specimen. The residual surface potentials associated with the localized trapped charge induced electric field have been mapped using KPM. Evidence of electro-diffusion and defect micro-segregation in charged beam irradiated silicon dioxide is observed. The associated mobile defect species are identified using CL microanalysis techniques. The high correlation between KPM and CL images confirms the significant influence of localized potentials on the microstructure of technologically important silicon dioxide. In order to relate the observed potentials to the electron beam induced specimen charging, the calculated potential profiles are evaluated using three dimensional conformal Finite Element Analysis. It is demonstrated that relatively simple models of specimen charging are able to account for the observed potentials resulting from focussed electron irradiation of poorly conducting materials. The complex processes involved in the production and spatial segregation of defects (e.g. interstitial molecular and atomic species) in poorly conducting materials are dependent on highly localized irradiation induced electric fields. When poorly conducting materials are irradiated with electrons, a sub-surface electric field may be induced due to the localization of charges at defects. Negatively charged species will migrate towards the surface, while positively charged species will migrate towards the region of maximum negative trapped charge, towards the base of the interaction volume. Electron beam irradiation of silicon dioxide produces characteristic highly correlated changes in the spatial distribution of CL emission, in the topography of the irradiated surface, and the localised residual surface potential

  17. Quantification of plant cell coupling with three-dimensional photoactivation microscopy.

    Science.gov (United States)

    Liesche, J; Schulz, A

    2012-07-01

    Plant cells are directly connected by plasmodesmata that form channels through the cell wall and enable the intercellular movement of cytosolic solutes, membrane lipids and signalling molecules. Transport through plasmodesmata is regulated not only by a fixed size-exclusion limit, but also by physiological and pathological adaptation. To understand plant cell communication, carbon allocation and pathogen attack, the capacities for a specific molecule to pass a specific cell-wall interface is an essential parameter. So far, the degree of cell coupling was derived from frequency and diameter of plasmodesmata in relevant tissues as assessed by electron microscopy of fixed material. However, plasmodesmata functionality and capacity can only be determined in live material, not from electron microscopy, which is static and prone to fixation artefacts. Plasmodesmata functionality was a few times assessed using fluorescent tracers with diffusion properties similar to cytosolic solutes. Here, we used three-dimensional photoactivation microscopy to quantify plasmodesmata-mediated cell-wall permeability between living Cucurbita maxima leaf mesophyll cells with caged fluorescein as tracer. For the first time, all necessary functional and anatomical data were gathered for each individual cell from three-dimensional time series. This approach utilized a confocal microscope equipped with resonant scanner, which provides the high acquisition speed necessary to record optical sections of whole cells and offers time resolution high enough to follow the kinetics of photoactivation. The results were compared to two-dimensional measurements, which are shown to give a good estimate of cell coupling adequate for homogenous tissues. The two-dimensional approach is limited whenever tissues interfaces are studied that couple different cell types with diverse cell geometries. © 2011 The Authors Journal of Microscopy © 2011 Royal Microscopical Society.

  18. Three dimensional analysis of laterally loaded piles

    International Nuclear Information System (INIS)

    Yilmaz, C.

    1987-01-01

    In this study static analysis of laterally loaded pile is studied by the three models. The first model is the beam on discrete elastic springs. This model is analyzed using a flexibility method. The second model is the beam on a two-parameter elastic foundation. This model is analyzed using the linear finite element method. The third model is the finite element model, using the three-dimensional iso-parametric parabolic brick element. Three-dimensional pile group analysis is also performed using elastic constants of single pile obtained by any one of the above analyses. The main objective is to develop computer programs for each model related to single piles and to group analysis. Then, the deflections, rotations, moments, shears, stresses and strains of the single pile are obtained at any arbitrary point. Comparison is made between each model and with other studies such as Poulos 1971, Desai and Appel 1976. In addition, to provide a benchmark of three-dimensional finite element analysis, the Boussinesq problem is analyzed. (orig.)

  19. Three-Dimensional Reconstruction of Sandpile Interiors

    Science.gov (United States)

    Seidler, G. T.

    2001-03-01

    The granular bed, or sandpile, has become one of the condensed matter physicist's favorite systems. In addition to conceptual appeal, the simplest sandpile of monodisperse hard spheres is a valuable model system for understanding powders, liquids, and metallic glasses. Any fundamental approach to the transport and mechanical properties of three-dimensional mesoscale disordered materials must follow from a thorough understanding of their structure. However, in the overwhelming majority of cases, structure measurements have been limited to the mean filling fraction and the structural autocorrelation function. This is particularly unfortunate in the ongoing sandpile renaissance, where some of the most interesting questions concern structure and the relationship between structure and dynamics. I will discuss the combination of synchrotron x-ray microtomography and computer vision algorithms to perform three-dimensional virtual reconstructions of real sandpiles. This technique is rapid and noninvasive, and is applicable to samples large enough to separate bulk and boundary properties. The resulting complete knowledge of structure can be used to calculate otherwise inaccessible correlation functions. I will present results for several measures of the bond-orientational order in three-dimensional sandpiles, including fabric tensors and nematic order parameters.

  20. High-resolution three-dimensional mapping of semiconductor dopant potentials

    DEFF Research Database (Denmark)

    Twitchett, AC; Yates, TJV; Newcomb, SB

    2007-01-01

    Semiconductor device structures are becoming increasingly three-dimensional at the nanometer scale. A key issue that must be addressed to enable future device development is the three-dimensional mapping of dopant distributions, ideally under "working conditions". Here we demonstrate how a combin......Semiconductor device structures are becoming increasingly three-dimensional at the nanometer scale. A key issue that must be addressed to enable future device development is the three-dimensional mapping of dopant distributions, ideally under "working conditions". Here we demonstrate how...... a combination of electron holography and electron tomography can be used to determine quantitatively the three-dimensional electrostatic potential in an electrically biased semiconductor device with nanometer spatial resolution....

  1. Three dimensional illustrating - three-dimensional vision and deception of sensibility

    Directory of Open Access Journals (Sweden)

    Anita Gánóczy

    2009-03-01

    Full Text Available The wide-spread digital photography and computer use gave the opportunity for everyone to make three-dimensional pictures and to make them public. The new opportunities with three-dimensional techniques give chance for the birth of new artistic photographs. We present in detail the biological roots of three-dimensional visualization, the phenomena of movement parallax, which can be used efficiently in making three-dimensional graphics, the Zöllner- and Corridor-illusion. There are present in this paper the visual elements, which contribute to define a plane two-dimensional image in three-dimension: coherent lines, the covering, the measurement changes, the relative altitude state, the abatement of detail profusion, the shadings and the perspective effects of colors.

  2. Three-dimensional analysis of craniofacial bones using three-dimensional computer tomography

    International Nuclear Information System (INIS)

    Ono, Ichiro; Ohura, Takehiko; Kimura, Chu

    1989-01-01

    Three-dimensional computer tomography (3DCT) was performed in patients with various diseases to visualize stereoscopically the deformity of the craniofacial bones. The data obtained were analyzed by the 3DCT analyzing system. A new coordinate system was established using the median sagittal plane of the face (a plane passing through sella, nasion and basion) on the three-dimensional image. Three-dimensional profilograms were prepared for detailed analysis of the deformation of craniofacial bones for cleft lip and palate, mandibular prognathia and hemifacial microsomia. For patients, asymmetry in the frontal view and twist-formed complicated deformities were observed, as well as deformity of profiles in the anteroposterior and up-and-down directions. A newly developed technique allows three-dimensional visualization of changes in craniofacial deformity. It would aid in determining surgical strategy, including crani-facial surgery and maxillo-facial surgery, and in evaluating surgical outcome. (N.K.)

  3. Three-dimensional analysis of craniofacial bones using three-dimensional computer tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Ichiro; Ohura, Takehiko; Kimura, Chu (Hokkaido Univ., Sapporo (Japan). School of Medicine) (and others)

    1989-08-01

    Three-dimensional computer tomography (3DCT) was performed in patients with various diseases to visualize stereoscopically the deformity of the craniofacial bones. The data obtained were analyzed by the 3DCT analyzing system. A new coordinate system was established using the median sagittal plane of the face (a plane passing through sella, nasion and basion) on the three-dimensional image. Three-dimensional profilograms were prepared for detailed analysis of the deformation of craniofacial bones for cleft lip and palate, mandibular prognathia and hemifacial microsomia. For patients, asymmetry in the frontal view and twist-formed complicated deformities were observed, as well as deformity of profiles in the anteroposterior and up-and-down directions. A newly developed technique allows three-dimensional visualization of changes in craniofacial deformity. It would aid in determining surgical strategy, including crani-facial surgery and maxillo-facial surgery, and in evaluating surgical outcome. (N.K.).

  4. The sinusoidal lining cells in "normal" human liver. A scanning electron microscopic investigation

    DEFF Research Database (Denmark)

    Horn, T; Henriksen, Jens Henrik Sahl; Christoffersen, P

    1986-01-01

    The scanning electron microscopic was used to study the fenestrations of human liver sinusoids. Thirteen biopsies, where light microscopy and transmission electron microscopy revealed normal sinusoidal architecture, were investigated. The number of fenestrae was calculated in acinar zone 3...

  5. Three-dimensional laser pulse intensity diagnostic for photoinjectors

    Directory of Open Access Journals (Sweden)

    Heng Li

    2011-11-01

    Full Text Available Minimizing the electron-beam emittance of photoinjectors is an important task for maximizing the brightness of the next-generation x-ray facilities, such as free-electron lasers and energy recovery linacs. Optimally shaped laser pulses can significantly reduce emittance. A reliable diagnostic for the laser pulse intensity is required for this purpose. We demonstrate measurement of three-dimensional spatiotemporal intensity profiles, with spatial resolution of 20  μm and temporal resolution of 130 fs. The capability is illustrated by measurements of stacked soliton pulses and pulses from a dissipative-soliton laser.

  6. Three-dimensional instability of standing waves

    Science.gov (United States)

    Zhu, Qiang; Liu, Yuming; Yue, Dick K. P.

    2003-12-01

    We investigate the three-dimensional instability of finite-amplitude standing surface waves under the influence of gravity. The analysis employs the transition matrix (TM) approach and uses a new high-order spectral element (HOSE) method for computation of the nonlinear wave dynamics. HOSE is an extension of the original high-order spectral method (HOS) wherein nonlinear wave wave and wave body interactions are retained up to high order in wave steepness. Instead of global basis functions in HOS, however, HOSE employs spectral elements to allow for complex free-surface geometries and surface-piercing bodies. Exponential convergence of HOS with respect to the total number of spectral modes (for a fixed number of elements) and interaction order is retained in HOSE. In this study, we use TM-HOSE to obtain the stability of general three-dimensional perturbations (on a two-dimensional surface) on two classes of standing waves: plane standing waves in a rectangular tank; and radial/azimuthal standing waves in a circular basin. For plane standing waves, we confirm the known result of two-dimensional side-bandlike instability. In addition, we find a novel three-dimensional instability for base flow of any amplitude. The dominant component of the unstable disturbance is an oblique (standing) wave oriented at an arbitrary angle whose frequency is close to the (nonlinear) frequency of the original standing wave. This finding is confirmed by direct long-time simulations using HOSE which show that the nonlinear evolution leads to classical Fermi Pasta Ulam recurrence. For the circular basin, we find that, beyond a threshold wave steepness, a standing wave (of nonlinear frequency Omega) is unstable to three-dimensional perturbations. The unstable perturbation contains two dominant (standing-wave) components, the sum of whose frequencies is close to 2Omega. From the cases we consider, the critical wave steepness is found to generally decrease/increase with increasing radial

  7. Three-dimensional cytomorphology in fine needle aspiration biopsy of medullary thyroid carcinoma.

    Science.gov (United States)

    Chang, T C; Lai, S M; Wen, C Y; Hsiao, Y L; Huang, S H

    2001-01-01

    To elucidate three-dimensional (3-D) cytomorphology in fine needle aspiration biopsy (FNAB) of medullary thyroid carcinoma (MTC). ENAB was performed on tumors from five patients with MTC. The aspirate was stained and observed under a light microscope (LM). The aspirate was also fixed, dehydrated, critical point dried, spattered with gold ions and observed with a scanning electron microscope (SEM). For transmission electron microscopy (TEM), the specimen was fixed, dehydrated, embedded in an Epon mixture, cut with an ultramicrotome, mounted on copper grids, electron doubly stained with uranium acetate and lead citrate, and observed with TEM. Findings under SEM were correlated with those under LM and TEM. Under SEM, 3-D cytomorphology of MTC displayed a disorganized cellular arrangement with indistinct cell borders in three cases. The cell surface was uneven and had granular protrusions that corresponded to secretory granules observed under TEM. In one case with multiple endocrine neoplasia type IIB, there were abundant granules on the cell surface. In one case of sporadic MTC with multinucleated tumor giant cells and small cells, granular protrusions also were noted on the cell surface. Granular protrusion was a characteristic finding in FNAB of MTC tinder SEM and might be helpful in the differential diagnosis.

  8. Phase Diagrams of Three-Dimensional Anderson and Quantum Percolation Models Using Deep Three-Dimensional Convolutional Neural Network

    Science.gov (United States)

    Mano, Tomohiro; Ohtsuki, Tomi

    2017-11-01

    The three-dimensional Anderson model is a well-studied model of disordered electron systems that shows the delocalization-localization transition. As in our previous papers on two- and three-dimensional (2D, 3D) quantum phase transitions [J. Phys. Soc. Jpn. 85, 123706 (2016), 86, 044708 (2017)], we used an image recognition algorithm based on a multilayered convolutional neural network. However, in contrast to previous papers in which 2D image recognition was used, we applied 3D image recognition to analyze entire 3D wave functions. We show that a full phase diagram of the disorder-energy plane is obtained once the 3D convolutional neural network has been trained at the band center. We further demonstrate that the full phase diagram for 3D quantum bond and site percolations can be drawn by training the 3D Anderson model at the band center.

  9. The Design and Construction of a Simple Transmission Electron Microscope for Educational Purposes.

    Science.gov (United States)

    Hearsey, Paul K.

    This document presents a model for a simple transmission electron microscope for educational purposes. This microscope could demonstrate thermonic emission, particle acceleration, electron deflection, and flourescence. It is designed to be used in high school science courses, particularly physics, taking into account the size, weight, complexity…

  10. Remote control scanning electron microscope with Web operation

    International Nuclear Information System (INIS)

    Yamada, A.; Hirahara, O.; Date, M.; Lozbin, V.; Tsuchida, T.; Sugano, N.

    2002-01-01

    Full text: Recently, SEM (Scanning Electron Microscope) and the other observation instruments are coming to use a LAN (Local Area Network) to save the image in the database. We developed a remote control system in which SEM image and Control interface is indicated on the WEB Browser. In this system, SEM can be controlled by an external (client) PC installed in a general WEB Browser (Internet Explorer). Accordingly, operation interface can be indicated on the WEB browser. A JSM-6700F is connected to a LAN, and so a client PC can control the microscope. The JSM-6700F has two lines to the LAN for image transfer and communication with the SEM control. In order to transfer the image, the image size squeezes from 1280 x 1024-pixels (SEM image size) to 640x480-pixels for quick transfer. The image signal (640 x 480-pixels) is connected to the video server only, and then the image transfers to the client PC via LAN. The SEM control communicates with client PC for external command. On the other hand, the SEM control interface and the image are indicated on WEB Browser (Internet explorer). The SEM control interface is composed of the SEM image area and the SEM control part. The SEM image indicates the 640x480-pixels live image. This live image is being used as a high resolution live image transfer in the image transfer technology which a network is used for at present. If it is LAN beyond 10 base, this indication of an image can be transferred fully. When it is connected in the small line of the capacity, the refresh speed of the image becomes slow because of image data doesn't finish transferring it. In such a case, image size can be changed smaller by the LAN conditions. When a high quality image is necessary, the image of 1280 x 1024-pixels is saved on a SEM (server) side by choosing the image save button. At the same time, the file kept in SEM (server) is transferred to the client PC automatically, so that we can display a high quality image on the client PC side. The

  11. Neural Network for Nanoscience Scanning Electron Microscope Image Recognition.

    Science.gov (United States)

    Modarres, Mohammad Hadi; Aversa, Rossella; Cozzini, Stefano; Ciancio, Regina; Leto, Angelo; Brandino, Giuseppe Piero

    2017-10-16

    In this paper we applied transfer learning techniques for image recognition, automatic categorization, and labeling of nanoscience images obtained by scanning electron microscope (SEM). Roughly 20,000 SEM images were manually classified into 10 categories to form a labeled training set, which can be used as a reference set for future applications of deep learning enhanced algorithms in the nanoscience domain. The categories chosen spanned the range of 0-Dimensional (0D) objects such as particles, 1D nanowires and fibres, 2D films and coated surfaces, and 3D patterned surfaces such as pillars. The training set was used to retrain on the SEM dataset and to compare many convolutional neural network models (Inception-v3, Inception-v4, ResNet). We obtained compatible results by performing a feature extraction of the different models on the same dataset. We performed additional analysis of the classifier on a second test set to further investigate the results both on particular cases and from a statistical point of view. Our algorithm was able to successfully classify around 90% of a test dataset consisting of SEM images, while reduced accuracy was found in the case of images at the boundary between two categories or containing elements of multiple categories. In these cases, the image classification did not identify a predominant category with a high score. We used the statistical outcomes from testing to deploy a semi-automatic workflow able to classify and label images generated by the SEM. Finally, a separate training was performed to determine the volume fraction of coherently aligned nanowires in SEM images. The results were compared with what was obtained using the Local Gradient Orientation method. This example demonstrates the versatility and the potential of transfer learning to address specific tasks of interest in nanoscience applications.

  12. Electron microscopic study on radiosensitivity of uterine cervical cancer

    Energy Technology Data Exchange (ETDEWEB)

    Iwai, S; Shiozawa, K; Tsukamoto, T; Noguchi, H; Tsukahara, Y [Shinshu Univ., Matsumoto, Nagano (Japan). Faculty of Medicine

    1974-11-01

    The effects of 1000 R of tele-cobalt upon the changes in the primary lesions of uterine cervical cancer with time were studied with an electron microscope. In addition, twenty cases which were proven to have cancer tissues (10 cases of IInd stage of cancer, 8 cases of IIIrd stage of cancer and 2 cases of IVth stage of cancer) were studied. Four cases were favourably sensitive, 7 cases moderately sensitive and 9 cases unfavourably sensitive to radiation. In favourably radio-sensitive cases, the changes in the cancer cells first appeared in the nucleus. There were other changes such as local clumping of chromatin and, specifically, vacuolization of the nucleus. The changes in the endoplasmic reticulum appeared somewhat late. In addition, the disturbance of mitochondria and the decrease or disappearance of ribosomes were specifically due to radiation injury. From the point of view of changes with time, Golgi's apparatus was enlarged and the membrane of the endoplasmic reticulum was degenerated at the 1st day. At the 3rd day, vacuolization of the nucleus appeared, the nuclear corpuscles were increased, the nucleoplasm became thin, and mitochondria was enlarged and degenerated. At the 5th day, the nuclear membrane disappeared, the nucleus was destroyed, large vacuolization of the endoplasmic reticulum was seen, free ribosomes were decreased, and changes around the endoplasmic reticulum were observed. At the 7th day, collagen around the endoplasmic reticulum appeared. In favourably radiosensitive cases, individual tumor cells showed the same degeneration, which fairly corresponded to that evaluated by the histological observation. The disturbance of the cells was caused by radiation, so-called ''burning'' of the cells. Radiation protection of the cells against burning was considered in terms of their radiosensitivity.

  13. Digital acquisition and processing of electron micrographs using a scanning transmission electron microscope

    International Nuclear Information System (INIS)

    Engel, A.; Christen, F.; Michel, B.

    1981-01-01

    A digital acquisition system that collects multichannel information from a scanning transmission electron microscope (STEM) and its application are described. The hardware comprises (i) single electron counting detectors, (ii) a digital scan generator, (iii) a digital multi-channel on-line processor, (iv) an interface to a minicomputer, and (v) a display system. Experimental results characterizing these components are presented, and their performance is discussed. The software includes assembler coded programs for dynamic file maintenance and fast acquisition of image data, a display driver, and FORTRAN coded application programs. The usefulness of digitized STEM is illustrated by a variety of biological applications. (orig.)

  14. Electron beam dynamics in an ultrafast transmission electron microscope with Wehnelt electrode

    Energy Technology Data Exchange (ETDEWEB)

    Bücker, K.; Picher, M.; Crégut, O. [Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 CNRS, Université de Strasbourg, 23 rue du Loess, 67034 Strasbourg (France); LaGrange, T. [Interdisciplinary Centre for Electron Microscopy, École Polytechnique Fédérale de Lausanne, 1015 Lausanne (Switzerland); Reed, B.W.; Park, S.T.; Masiel, D.J. [Integrated Dynamic Electron Solutions, Inc., 5653 Stoneridge Drive 117, Pleasanton, CA 94588 (United States); Banhart, F., E-mail: florian.banhart@ipcms.unistra.fr [Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 CNRS, Université de Strasbourg, 23 rue du Loess, 67034 Strasbourg (France)

    2016-12-15

    High temporal resolution transmission electron microscopy techniques have shown significant progress in recent years. Using photoelectron pulses induced by ultrashort laser pulses on the cathode, these methods can probe ultrafast materials processes and have revealed numerous dynamic phenomena at the nanoscale. Most recently, the technique has been implemented in standard thermionic electron microscopes that provide a flexible platform for studying material's dynamics over a wide range of spatial and temporal scales. In this study, the electron pulses in such an ultrafast transmission electron microscope are characterized in detail. The microscope is based on a thermionic gun with a Wehnelt electrode and is operated in a stroboscopic photoelectron mode. It is shown that the Wehnelt bias has a decisive influence on the temporal and energy spread of the picosecond electron pulses. Depending on the shape of the cathode and the cathode-Wehnelt distance, different emission patterns with different pulse parameters are obtained. The energy spread of the pulses is determined by space charge and Boersch effects, given by the number of electrons in a pulse. However, filtering effects due to the chromatic aberrations of the Wehnelt electrode allow the extraction of pulses with narrow energy spreads. The temporal spread is governed by electron trajectories of different length and in different electrostatic potentials. High temporal resolution is obtained by excluding shank emission from the cathode and aberration-induced halos in the emission pattern. By varying the cathode-Wehnelt gap, the Wehnelt bias, and the number of photoelectrons in a pulse, tradeoffs between energy and temporal resolution as well as beam intensity can be made as needed for experiments. Based on the characterization of the electron pulses, the optimal conditions for the operation of ultrafast TEMs with thermionic gun assembly are elaborated. - Highlights: • A detailed characterization of electron

  15. Spin polarized electron source technology transferred from HE accelerators to electron microscopes

    International Nuclear Information System (INIS)

    Nakanishi, Tsutomu

    2009-01-01

    For many years, we have developed a technology of spin-polarized-electron-source (PES) for a future linear collider project (ILC). Various new techniques for achieving high polarization, high quantum efficiency, high current density, sub-nanosecond multi-bunch generation etc. were developed. Two fundamental technologies; reduction of dark current and preparation of extremely high vacuum environment to protect the Negative Electron Affinity (NEA) surface have been also developed. Using these PES technologies and a new transmission type photocathode, we recently succeeded in producing the high brightness and high polarization electron beam for the low energy electron microscope (LEEM). Our Spin-LEEM system enables the world-first dynamic observation of surface magnetic domain formed by evaporation on the metal substrate with ∼ 20 nm space resolutions. (author)

  16. Simulation of electron displacement damage in a high voltage electron microscope

    International Nuclear Information System (INIS)

    Ono, Susumu; Kanaya, Koichi

    1979-01-01

    By applying the fundamental theory of the neutron cooling to the conservation law of energy and momentum, the threshold energies of incident electrons for displacing atoms are calculated and illustrated periodically for the atomic number. And the observable damage due to the secondary action of displaced atoms in the practical use of a high voltage electron microscope is described for several materials and accelerating voltages. The trajectories of incident electrons and displaced atoms in several materials are simulated by a Monte-Carlo method, using rigorous formulas of electron scattering events, i.e. elastic and inelastic scattering cross-sections, ionization loss and plasmon excitation. The simulation results are substantially agreement with experiments. (author)

  17. On the Progress of Scanning Transmission Electron Microscopy (STEM) Imaging in a Scanning Electron Microscope.

    Science.gov (United States)

    Sun, Cheng; Müller, Erich; Meffert, Matthias; Gerthsen, Dagmar

    2018-04-01

    Transmission electron microscopy (TEM) with low-energy electrons has been recognized as an important addition to the family of electron microscopies as it may avoid knock-on damage and increase the contrast of weakly scattering objects. Scanning electron microscopes (SEMs) are well suited for low-energy electron microscopy with maximum electron energies of 30 keV, but they are mainly used for topography imaging of bulk samples. Implementation of a scanning transmission electron microscopy (STEM) detector and a charge-coupled-device camera for the acquisition of on-axis transmission electron diffraction (TED) patterns, in combination with recent resolution improvements, make SEMs highly interesting for structure analysis of some electron-transparent specimens which are traditionally investigated by TEM. A new aspect is correlative SEM, STEM, and TED imaging from the same specimen region in a SEM which leads to a wealth of information. Simultaneous image acquisition gives information on surface topography, inner structure including crystal defects and qualitative material contrast. Lattice-fringe resolution is obtained in bright-field STEM imaging. The benefits of correlative SEM/STEM/TED imaging in a SEM are exemplified by structure analyses from representative sample classes such as nanoparticulates and bulk materials.

  18. Three-dimensional stereo by photometric ratios

    International Nuclear Information System (INIS)

    Wolff, L.B.; Angelopoulou, E.

    1994-01-01

    We present a methodology for corresponding a dense set of points on an object surface from photometric values for three-dimensional stereo computation of depth. The methodology utilizes multiple stereo pairs of images, with each stereo pair being taken of the identical scene but under different illumination. With just two stereo pairs of images taken under two different illumination conditions, a stereo pair of ratio images can be produced, one for the ratio of left-hand images and one for the ratio of right-hand images. We demonstrate how the photometric ratios composing these images can be used for accurate correspondence of object points. Object points having the same photometric ratio with respect to two different illumination conditions constitute a well-defined equivalence class of physical constraints defined by local surface orientation relative to illumination conditions. We formally show that for diffuse reflection the photometric ratio is invariant to varying camera characteristics, surface albedo, and viewpoint and that therefore the same photometric ratio in both images of a stereo pair implies the same equivalence class of physical constraints. The correspondence of photometric ratios along epipolar lines in a stereo pair of images under different illumination conditions is a correspondence of equivalent physical constraints, and the determination of depth from stereo can be performed. Whereas illumination planning is required, our photometric-based stereo methodology does not require knowledge of illumination conditions in the actual computation of three-dimensional depth and is applicable to perspective views. This technique extends the stereo determination of three-dimensional depth to smooth featureless surfaces without the use of precisely calibrated lighting. We demonstrate experimental depth maps from a dense set of points on smooth objects of known ground-truth shape, determined to within 1% depth accuracy

  19. Three-dimensional CT of the mandible

    International Nuclear Information System (INIS)

    Zinreich, S.J.; Price, J.C.; Wang, H.; Ahn, H.S.; Kashima, H.

    1988-01-01

    Seventeen patients with mandibular oblation for facial neoplasia, primary neoplasm, and trauma were evaluated with CT and three-dimensional CT. In eight of these patients, a computerized acrylic model was generated for preoperative planning and postoperative reconstruction. The ramus and body of the mandible were reconstructed with mirror image and fusion techniques. Reconstructions of the anterior mandible were generated from models including the midface, skull based, and residual mandibular fragments. The results are preliminary; however, the authors believe that these represent a powerful new tool and a significant advance in mandibular reconstructive technique, reduced anesthesia time, and the optimized restoration of dental alignment and facial contour

  20. Three-dimensional interpretation of TEM soundings

    Science.gov (United States)

    Barsukov, P. O.; Fainberg, E. B.

    2013-07-01

    We describe the approach to the interpretation of electromagnetic (EM) sounding data which iteratively adjusts the three-dimensional (3D) model of the environment by local one-dimensional (1D) transformations and inversions and reconstructs the geometrical skeleton of the model. The final 3D inversion is carried out with the minimal number of the sought parameters. At each step of the interpretation, the model of the medium is corrected according to the geological information. The practical examples of the suggested method are presented.

  1. Three-dimensional flow about penguin wings

    Science.gov (United States)

    Noca, Flavio; Sudki, Bassem; Lauria, Michel

    2012-11-01

    Penguins, contrary to airborne birds, do not need to compensate for gravity. Yet, the kinematics of their wings is highly three-dimensional and seems exceedingly complex for plain swimming. Is such kinematics the result of an evolutionary optimization or is it just a forced adaptation of an airborne flying apparatus to underwater swimming? Some answers will be provided based on flow dynamics around robotic penguin wings. Updates will also be presented on the development of a novel robotic arm intended to simulate penguin swimming and enable novel propulsion devices.

  2. Creating three-dimensional thermal maps

    CSIR Research Space (South Africa)

    Price

    2011-11-01

    Full Text Available stream_source_info Price_2011.pdf.txt stream_content_type text/plain stream_size 30895 Content-Encoding ISO-8859-1 stream_name Price_2011.pdf.txt Content-Type text/plain; charset=ISO-8859-1 Creating Three...-Dimensional Thermal Maps Mathew Price Cogency cc Cape Town Email: mathew@cogency.co.za Jeremy Green CSIR Centre for Mining Innovation Johannesburg Email: jgreen@csir.co.za John Dickens CSIR Centre for Mining Innovation Johannesburg Email: jdickens...

  3. Three-dimensional cooling of muons

    CERN Document Server

    Vsevolozhskaya, T A

    2000-01-01

    The simultaneous ionization cooling of muon beams in all three - the longitudinal and two transverse - directions is considered in a scheme, based on bent lithium lenses with dipole constituent of magnetic field in them, created by a special configuration of current-carrying rod. An analysis of three-dimensional cooling is performed with the use of kinetic equation method. Results of numerical calculation for a specific beam line configuration are presented together with results of computer simulation using the Moliere distribution to describe the Coulomb scattering and the Vavilov distribution used to describe the ionization loss of energy.

  4. Linking experiment and theory for three-dimensional networked binary metal nanoparticle–triblock terpolymer superstructures

    KAUST Repository

    Li, Zihui; Hur, Kahyun; Sai, Hiroaki; Higuchi, Takeshi; Takahara, Atsushi; Jinnai, Hiroshi; Gruner, Sol M.; Wiesner, Ulrich

    2014-01-01

    the intimate coupling of synthesis, in-depth electron tomographic characterization and theory enables exquisite control of superstructure in highly ordered porous three-dimensional continuous networks from single and binary mixtures of metal nanoparticles

  5. The three-dimensional microstructure of polycrystalline materials unravelled by synchrotron light

    DEFF Research Database (Denmark)

    Ludwig, W.; King, A.; Herbig, M.

    2011-01-01

    The three-dimensional microstructure of polycrystalline materials unravelled by synchrotron light Synchrotron radiation X-ray imaging and diffraction techniques offer new possibilities for non-destructive bulk characterization of polycrystalline materials. Minute changes in electron density (diff...

  6. Microscopic Superconductivity and Room Temperature Electronics of High-Tc Cuprates

    International Nuclear Information System (INIS)

    Liu Fusui; Chen Wanfang

    2008-01-01

    This paper points out that the Landau criterion for macroscopic superfluidity of He II is only a criterion for microscopic superfluidity of 4 He, extends the Landau criterion to microscopic superconductivity in fermions (electron and hole) system and system with Cooper pairs without long-range phase coherence. This paper gives another three non-superconductive systems that are of microscopic superconductivity. This paper demonstrates that one application of microscopic superconductivity is to establish room temperature electronics of the high-T c cuprates

  7. Three-dimensional radiation treatment planning

    International Nuclear Information System (INIS)

    Mohan, R.

    1989-01-01

    A major aim of radiation therapy is to deliver sufficient dose to the tumour volume to kill the cancer cells while sparing the nearby health organs to prevent complications. With the introduction of devices such as CT and MR scanners, radiation therapy treatment planners have access to full three-dimensional anatomical information to define, simulate, and evaluate treatments. There are a limited number of prototype software systems that allow 3D treatment planning currently in use. In addition, there are more advanced tools under development or still in the planning stages. They require sophisticated graphics and computation equipment, complex physical and mathematical algorithms, and new radiation treatment machines that deliver dose very precisely under computer control. Components of these systems include programs for the identification and delineation of the anatomy and tumour, the definition of radiation beams, the calculation of dose distribution patterns, the display of dose on 2D images and as three dimensional surfaces, and the generation of computer images to verify proper patient positioning in treatment. Some of these functions can be performed more quickly and accurately if artificial intelligence or expert systems techniques are employed. 28 refs., figs

  8. Three-dimensional fluorescence lifetime tomography

    International Nuclear Information System (INIS)

    Godavarty, Anuradha; Sevick-Muraca, Eva M.; Eppstein, Margaret J.

    2005-01-01

    Near-infrared fluorescence tomography using molecularly targeted lifetime-sensitive, fluorescent contrast agents have applications for early-stage cancer diagnostics. Yet, although the measurement of fluorescent lifetime imaging microscopy (FLIM) is extensively used in microscopy and spectroscopy applications, demonstration of fluorescence lifetime tomography for medical imaging is limited to two-dimensional studies. Herein, the feasibility of three-dimensional fluorescence-lifetime tomography on clinically relevant phantom volumes is established, using (i) a gain-modulated intensified charge coupled device (CCD) and modulated laser diode imaging system, (ii) two fluorescent contrast agents, e.g., Indocyanine green and 3-3'-Diethylthiatricarbocyanine iodide differing in their fluorescence lifetime by 0.62 ns, and (iii) a two stage approximate extended Kalman filter reconstruction algorithm. Fluorescence measurements of phase and amplitude were acquired on the phantom surface under different target to background fluorescence absorption (70:1, 100:1) and fluorescence lifetime (1:1, 2.1:1) contrasts at target depths of 1.4-2 cm. The Bayesian tomography algorithm was employed to obtain three-dimensional images of lifetime and absorption owing to the fluorophores

  9. Three-dimensional image signals: processing methods

    Science.gov (United States)

    Schiopu, Paul; Manea, Adrian; Craciun, Anca-Ileana; Craciun, Alexandru

    2010-11-01

    Over the years extensive studies have been carried out to apply coherent optics methods in real-time processing, communications and transmission image. This is especially true when a large amount of information needs to be processed, e.g., in high-resolution imaging. The recent progress in data-processing networks and communication systems has considerably increased the capacity of information exchange. We describe the results of literature investigation research of processing methods for the signals of the three-dimensional images. All commercially available 3D technologies today are based on stereoscopic viewing. 3D technology was once the exclusive domain of skilled computer-graphics developers with high-end machines and software. The images capture from the advanced 3D digital camera can be displayed onto screen of the 3D digital viewer with/ without special glasses. For this is needed considerable processing power and memory to create and render the complex mix of colors, textures, and virtual lighting and perspective necessary to make figures appear three-dimensional. Also, using a standard digital camera and a technique called phase-shift interferometry we can capture "digital holograms." These are holograms that can be stored on computer and transmitted over conventional networks. We present some research methods to process "digital holograms" for the Internet transmission and results.

  10. Three dimensional animated images of anorectal malformations

    International Nuclear Information System (INIS)

    Ueno, Shigeru; Yanagimachi, Noriharu; Muro, Isao; Komiya, Taizo; Yokoyama, Seishichi; Hirakawa, Hitoshi; Tajima, Tomoo; Mitomi, Toshio; Suto, Yasuzo.

    1996-01-01

    Accurate reconstruction of the pelvic structures is a most important factor in obtaining a desirable result after anorectoplasty for a patient with anorectal malformation. Preoperative evaluation of the anatomy is indispensable for choosing an appropriate operative method in each case. To facilitate preoperative evaluation, three dimensional animated images of the pelvic structure of patients with anorectal malformations were constructed by computer graphics based upon tomographic images obtained from magnetic resonance imaging. Axial 1-mm thick images of the pelvic portion were generated with spoiling pulse gradient echo sequences using short repetition times (13 msec TR) and short echo times (6 msec TE) with a flip angle of 25 degrees with the patient in the jack-knife position. Graphic data from MR images were transferred to a graphic work station and processed on it. The skin surface, the ano-rectum, the lower urinary tract and the sphincter musculature were segmented by thresholding images by the signal intensity. Three dimensional images were displayed by surface rendering method using the segmented data of each organ and then animation images of these organs were obtained. The anatomy of each type of anomaly was easily recognized by 3-D visualization, and animation of the pelvic viscera and the sphincter musculature made the images more realistic. Animated images of the musculature were especially useful for simulating surgical procedures and could be helpful for reviewing surgical results. (author)

  11. Three-dimensional analysis of antenna sheaths

    International Nuclear Information System (INIS)

    Myra, J.R.; D'Ippolito, D.A.; Ho, Y.L.

    1996-01-01

    The present work is motivated by the importance of r.f. sheaths in determining the antenna-plasma interaction and the sensitivity of the sheaths to the complicated three-dimensional structure of modern ion cyclotron range of frequency (ICRF) antennas. To analyze r.f. sheaths on the plasma facing regions of the launcher, we first calculate the contact points of the tokamak magnetic field lines on the surface of the antenna Faraday screen and nearby limiters for realistic three-dimensional magnetic flux surface and antenna geometries. Next, the r.f. voltage that can drive sheaths at the contact points is determined and used to assess the resulting sheath power dissipation, r.f.-driven sputtering, and r.f.-induced convective cells (which produce edge profile modification). The calculations are embodied in a computer code, ANSAT (antenna sheath analysis tool), and sample ANSAT runs are shown to highlight the physics- and geometry-dependent characteristics of the r.f. sheaths and their relationship to the antenna design. One use of ANSAT is therefore as a design tool, to assess the strengths and weaknesses of a given design with respect to critical voltage handling and edge plasma interaction issues. Additionally, examples are presented where ANSAT has been useful in the analysis and interpretation of ICRF experiments (orig.)

  12. Transmission electron microscope studies of crystalline LiNbO3

    International Nuclear Information System (INIS)

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

    1984-01-01

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

  13. Apparatus and methods for controlling electron microscope stages

    Science.gov (United States)

    Duden, Thomas

    2015-08-11

    Methods and apparatus for generating an image of a specimen with a microscope (e.g., TEM) are disclosed. In one aspect, the microscope may generally include a beam generator, a stage, a detector, and an image generator. A plurality of crystal parameters, which describe a plurality of properties of a crystal sample, are received. In a display associated with the microscope, an interactive control sphere based at least in part on the received crystal parameters and that is rotatable by a user to different sphere orientations is presented. The sphere includes a plurality of stage coordinates that correspond to a plurality of positions of the stage and a plurality of crystallographic pole coordinates that correspond to a plurality of polar orientations of the crystal sample. Movement of the sphere causes movement of the stage, wherein the stage coordinates move in conjunction with the crystallographic coordinates represented by pole positions so as to show a relationship between stage positions and the pole positions.

  14. A simple way to obtain backscattered electron images in a scanning transmission electron microscope.

    Science.gov (United States)

    Tsuruta, Hiroki; Tanaka, Shigeyasu; Tanji, Takayoshi; Morita, Chiaki

    2014-08-01

    We have fabricated a simple detector for backscattered electrons (BSEs) and incorporated the detector into a scanning transmission electron microscope (STEM) sample holder. Our detector was made from a 4-mm(2) Si chip. The fabrication procedure was easy, and similar to a standard transmission electron microscopy (TEM) sample thinning process based on ion milling. A TEM grid containing particle objects was fixed to the detector with a silver paste. Observations were carried out using samples of Au and latex particles at 75 and 200 kV. Such a detector provides an easy way to obtain BSE images in an STEM. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Three-dimensional morphology of the human embryonic brain

    Directory of Open Access Journals (Sweden)

    N. Shiraishi

    2015-09-01

    Full Text Available The morphogenesis of the cerebral vesicles and ventricles was visualized in 3D movies using images derived from human embryo specimens between Carnegie stage 13 and 23 from the Kyoto Collection. These images were acquired with a magnetic resonance microscope equipped with a 2.35-T superconducting magnet. Three-dimensional images using the same scale demonstrated brain development and growth effectively. The non-uniform thickness of the brain tissue, which may indicate brain differentiation, was visualized with thickness-based surface color mapping. A closer view was obtained of the unique and complicated differentiation of the rhombencephalon, especially with regard to the internal view and thickening of the brain tissue. The present data contribute to a better understanding of brain and cerebral ventricle development.

  16. Wave field restoration using three-dimensional Fourier filtering method.

    Science.gov (United States)

    Kawasaki, T; Takai, Y; Ikuta, T; Shimizu, R

    2001-11-01

    A wave field restoration method in transmission electron microscopy (TEM) was mathematically derived based on a three-dimensional (3D) image formation theory. Wave field restoration using this method together with spherical aberration correction was experimentally confirmed in through-focus images of amorphous tungsten thin film, and the resolution of the reconstructed phase image was successfully improved from the Scherzer resolution limit to the information limit. In an application of this method to a crystalline sample, the surface structure of Au(110) was observed in a profile-imaging mode. The processed phase image showed quantitatively the atomic relaxation of the topmost layer.

  17. Three-dimensional graphene networks: synthesis,properties and applications

    Institute of Scientific and Technical Information of China (English)

    Yanfeng Ma; Yongsheng Chen

    2015-01-01

    Recently, three-dimensional graphene/graphene oxide(GO) networks(3DGNs) in the form of foams,sponges and aerogels have atracted much atention. 3D structures provide graphene materials with high speciic surface areas, large pore volumes, strong mechanical strengths and fast mass and electron transport,owing to the combination of the 3D porous structures and the excellent intrinsic properties of graphene.his review focuses on the latest advances in the preparation, properties and potential applications of 3D micro-/nano-architectures made of graphene/GO-based networks, with emphasis on graphene foams and sponges.

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

    Science.gov (United States)

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

    2018-06-01

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

  19. Analytical electron microscope based on scanning transmission electron microscope with wavelength dispersive x-ray spectroscopy to realize highly sensitive elemental imaging especially for light elements

    International Nuclear Information System (INIS)

    Koguchi, Masanari; Tsuneta, Ruriko; Anan, Yoshihiro; Nakamae, Koji

    2017-01-01

    An analytical electron microscope based on the scanning transmission electron microscope with wavelength dispersive x-ray spectroscopy (STEM-WDX) to realize highly sensitive elemental imaging especially for light elements has been developed. In this study, a large-solid-angle multi-capillary x-rays lens with a focal length of 5 mm, long-time data acquisition (e.g. longer than 26 h), and a drift-free system made it possible to visualize boron-dopant images in a Si substrate at a detection limit of 0.2 atomic percent. (paper)

  20. Imaging single atoms using secondary electrons with an aberration-corrected electron microscope.

    Science.gov (United States)

    Zhu, Y; Inada, H; Nakamura, K; Wall, J

    2009-10-01

    Aberration correction has embarked on a new frontier in electron microscopy by overcoming the limitations of conventional round lenses, providing sub-angstrom-sized probes. However, improvement of spatial resolution using aberration correction so far has been limited to the use of transmitted electrons both in scanning and stationary mode, with an improvement of 20-40% (refs 3-8). In contrast, advances in the spatial resolution of scanning electron microscopes (SEMs), which are by far the most widely used instrument for surface imaging at the micrometre-nanometre scale, have been stagnant, despite several recent efforts. Here, we report a new SEM, with aberration correction, able to image single atoms by detecting electrons emerging from its surface as a result of interaction with the small probe. The spatial resolution achieved represents a fourfold improvement over the best-reported resolution in any SEM (refs 10-12). Furthermore, we can simultaneously probe the sample through its entire thickness with transmitted electrons. This ability is significant because it permits the selective visualization of bulk atoms and surface ones, beyond a traditional two-dimensional projection in transmission electron microscopy. It has the potential to revolutionize the field of microscopy and imaging, thereby opening the door to a wide range of applications, especially when combined with simultaneous nanoprobe spectroscopy.

  1. Turbulence in Three Dimensional Simulations of Magnetopause Reconnection

    Science.gov (United States)

    Drake, J. F.; Price, L.; Swisdak, M.; Burch, J. L.; Cassak, P.; Dahlin, J. T.; Ergun, R.

    2017-12-01

    We present two- and three-dimensional particle-in-cell simulations of the 16 October 2015 MMS magnetopause reconnection event. While the two-dimensional simulation is laminar, turbulence develops at both the x-line and along the magnetic separatrices in the three-dimensional simulation. This turbulence is electromagnetic in nature, is characterized by a wavevector k given by kρ e ˜(m_e/m_i)0.25 with ρ e the electron Larmor radius, and appears to have the ion pressure gradient as its source of free energy. Taken together, these results suggest the instability is a variant of the lower-hybrid drift instability. The turbulence produces electric field fluctuations in the out-of-plane direction (the direction of the reconnection electric field) with an amplitude of around ± 10 mV/m, which is much greater than the reconnection electric field of around 0.1 mV/m. Such large values of the out-of-plane electric field have been identified in the MMS data. The turbulence in the simulation controls the scale lengths of the density profile and current layers in asymmetric reconnection, driving them closer to √ {ρ eρ_i } than the ρ e or de scalings seen in 2D reconnection simulations, where de is the electron inertial length. The turbulence is strong enough to make the magnetic field around the reconnection island chaotic and produces both anomalous resistivity and anomalous viscosity. Each contribute significantly to breaking the frozen-in condition in the electron diffusion region. The crescent-shaped features in velocity space seen both in MMS observations and in two-dimensional simulations survive, even in the turbulent environment of the three-dimensional system. We compare and contrast these results to a three-dimensional simulation of the 8 December 2015 MMS magnetopause reconnection event in which the reconnecting and out-of-plane guide fields are comparable. LHDI is still present in this event, although its appearance is modified by the presence of the guide

  2. Steady, three-dimensional, internally heated convection

    International Nuclear Information System (INIS)

    Schubert, G.; Glatzmaier, G.A.; Travis, B.

    1993-01-01

    Numerical calculations have been carried out of steady, symmetric, three-dimensional modes of convection in internally heated, infinite Prandtl number, Boussinesq fluids at a Rayleigh number of 1.4x10 4 in a spherical shell with inner/outer radius of 0.55 and in a 3x3x1 rectangular box. Multiple patterns of convection occur in both geometries. In the Cartesian geometry the patterns are dominated by cylindrical cold downflows and a broad hot upwelling. In the spherical geometry the patterns consist of cylindrical cold downwellings centered either at the vertices of a tetrahedron or the centers of the faces of a cube. The cold downflow cylinders are immersed in a background of upwelling within which there are cylindrical hot concentrations (plumes) and hot halos around the downflows. The forced hot upflow return plumes of internally heated spherical convection are fundamentally different from the buoyancy-driven plumes of heated from below convection

  3. Exact solutions in three-dimensional gravity

    CERN Document Server

    Garcia-Diaz, Alberto A

    2017-01-01

    A self-contained text, systematically presenting the determination and classification of exact solutions in three-dimensional Einstein gravity. This book explores the theoretical framework and general physical and geometrical characteristics of each class of solutions, and includes information on the researchers responsible for their discovery. Beginning with the physical character of the solutions, these are identified and ordered on the basis of their geometrical invariant properties, symmetries, and algebraic classifications, or from the standpoint of their physical nature, for example electrodynamic fields, fluid, scalar field, or dilaton. Consequently, this text serves as a thorough catalogue on 2+1 exact solutions to the Einstein equations coupled to matter and fields, and on vacuum solutions of topologically massive gravity with a cosmological constant. The solutions are also examined from different perspectives, enabling a conceptual bridge between exact solutions of three- and four-dimensional gravit...

  4. Three-dimensional printing physiology laboratory technology.

    Science.gov (United States)

    Sulkin, Matthew S; Widder, Emily; Shao, Connie; Holzem, Katherine M; Gloschat, Christopher; Gutbrod, Sarah R; Efimov, Igor R

    2013-12-01

    Since its inception in 19th-century Germany, the physiology laboratory has been a complex and expensive research enterprise involving experts in various fields of science and engineering. Physiology research has been critically dependent on cutting-edge technological support of mechanical, electrical, optical, and more recently computer engineers. Evolution of modern experimental equipment is constrained by lack of direct communication between the physiological community and industry producing this equipment. Fortunately, recent advances in open source technologies, including three-dimensional printing, open source hardware and software, present an exciting opportunity to bring the design and development of research instrumentation to the end user, i.e., life scientists. Here we provide an overview on how to develop customized, cost-effective experimental equipment for physiology laboratories.

  5. Three-dimensional hologram display system

    Science.gov (United States)

    Mintz, Frederick (Inventor); Chao, Tien-Hsin (Inventor); Bryant, Nevin (Inventor); Tsou, Peter (Inventor)

    2009-01-01

    The present invention relates to a three-dimensional (3D) hologram display system. The 3D hologram display system includes a projector device for projecting an image upon a display medium to form a 3D hologram. The 3D hologram is formed such that a viewer can view the holographic image from multiple angles up to 360 degrees. Multiple display media are described, namely a spinning diffusive screen, a circular diffuser screen, and an aerogel. The spinning diffusive screen utilizes spatial light modulators to control the image such that the 3D image is displayed on the rotating screen in a time-multiplexing manner. The circular diffuser screen includes multiple, simultaneously-operated projectors to project the image onto the circular diffuser screen from a plurality of locations, thereby forming the 3D image. The aerogel can use the projection device described as applicable to either the spinning diffusive screen or the circular diffuser screen.

  6. Three-dimensional echocardiography in valve disease

    Directory of Open Access Journals (Sweden)

    Cesare Fiorentini

    2009-08-01

    Full Text Available This review covers the role of three-dimensional (3D echocardiography in the diagnosis of heart valve disease. Several factors have contributed to the evolution of this technique, which is currently a simple and routine method: rapid evolution in probe and computer technologies, demonstration that 3D data sets allowed more complete and accurate evaluation of cardiac structures, emerging clinical experience indicating the strong potential particularly in valve diseases, volume and function of the two ventricle measurements and several other fields. This report will review current and future applications of 3D echocardiography in mitral, aortic and tricuspid valve diseases underlying both qualitative (morphologic and quantitative advantages of this technique. (Heart International 2007; 3: 35-41

  7. An Introduction of Three-dimensional Grammar

    Directory of Open Access Journals (Sweden)

    Fan Xiao

    2017-12-01

    Full Text Available This paper introduces some key points of Three-dimensional Grammar. As for the structure, it can be distinguished into syntactic structure, semantic structure and pragmatic structure from the perspectives of syntax, semantics and pragmatics. And the same is true with the followings, such as grammatical constituents, grammatical functions, grammatical meanings, grammatical focuses. Sentence types which is called sentence pattern, sentence model and sentence types respectively, and analysis methods. This paper proposes that grammatical researches should be done in accordance with the four principles, that is form and meaning co-verified, static and dynamic co-referenced, structure and function co-testified and description and interpretation co-promoted.

  8. Three-dimensional function photonic crystals

    Science.gov (United States)

    Zhang, Hai-Feng

    2017-11-01

    In this paper, the properties of the photonic band gaps (PBGs) of three-dimensional (3D) function photonic crystals (PCs) are theoretically investigated by a modified plane wave expansion (PWE) method, whose equations for computations are deduced. The configuration of 3D function PCs is the dielectric spheres inserted in the air background with simple-cubic (SC) lattices whose dielectric constants are the functions of space coordinates, which can be realized by the electro-optical or optical Kerr effect in the practice. The influences of the parameter for 3D function PCs on the PBGs also are discussed. The calculated results show that the bandwidths and number of PBGs can be tuned with different distributions of function dielectrics. Compared with the conventional 3D dielectric PCs with SC lattices, the larger and more PBGs can be obtained in the 3D function PCs. Those results provide a new way to design the novel practical devices.

  9. Three-dimensional tori and Arnold tongues

    Energy Technology Data Exchange (ETDEWEB)

    Sekikawa, Munehisa, E-mail: sekikawa@cc.utsunomiya-u.ac.jp [Department of Mechanical and Intelligent Engineering, Utsunomiya University, Utsunomiya-shi 321-8585 (Japan); Inaba, Naohiko [Organization for the Strategic Coordination of Research and Intellectual Property, Meiji University, Kawasaki-shi 214-8571 (Japan); Kamiyama, Kyohei [Department of Electronics and Bioinformatics, Meiji University, Kawasaki-shi 214-8571 (Japan); Aihara, Kazuyuki [Institute of Industrial Science, the University of Tokyo, Meguro-ku 153-8505 (Japan)

    2014-03-15

    This study analyzes an Arnold resonance web, which includes complicated quasi-periodic bifurcations, by conducting a Lyapunov analysis for a coupled delayed logistic map. The map can exhibit a two-dimensional invariant torus (IT), which corresponds to a three-dimensional torus in vector fields. Numerous one-dimensional invariant closed curves (ICCs), which correspond to two-dimensional tori in vector fields, exist in a very complicated but reasonable manner inside an IT-generating region. Periodic solutions emerge at the intersections of two different thin ICC-generating regions, which we call ICC-Arnold tongues, because all three independent-frequency components of the IT become rational at the intersections. Additionally, we observe a significant bifurcation structure where conventional Arnold tongues transit to ICC-Arnold tongues through a Neimark-Sacker bifurcation in the neighborhood of a quasi-periodic Hopf bifurcation (or a quasi-periodic Neimark-Sacker bifurcation) boundary.

  10. Multiscale modeling of three-dimensional genome

    Science.gov (United States)

    Zhang, Bin; Wolynes, Peter

    The genome, the blueprint of life, contains nearly all the information needed to build and maintain an entire organism. A comprehensive understanding of the genome is of paramount interest to human health and will advance progress in many areas, including life sciences, medicine, and biotechnology. The overarching goal of my research is to understand the structure-dynamics-function relationships of the human genome. In this talk, I will be presenting our efforts in moving towards that goal, with a particular emphasis on studying the three-dimensional organization, the structure of the genome with multi-scale approaches. Specifically, I will discuss the reconstruction of genome structures at both interphase and metaphase by making use of data from chromosome conformation capture experiments. Computationally modeling of chromatin fiber at atomistic level from first principles will also be presented as our effort for studying the genome structure from bottom up.

  11. Three-dimensional reconstruction of CT images

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Toshiaki; Kattoh, Keiichi; Kawakami, Genichiroh; Igami, Isao; Mariya, Yasushi; Nakamura, Yasuhiko; Saitoh, Yohko; Tamura, Koreroku; Shinozaki, Tatsuyo

    1986-09-01

    Computed tomography (CT) has the ability to provide sensitive visualization of organs and lesions. Owing to the nature of CT to be transaxial images, a structure which is greater than a certain size appears as several serial CT images. Consequently each observer must reconstruct those images into a three-dimensional (3-D) form mentally. It has been supposed to be of great use if such a 3-D form can be described as a definite figure. A new computer program has been developed which can produce 3-D figures from the profiles of organs and lesions on CT images using spline curves. The figures obtained through this method are regarded to have practical applications.

  12. Full three-dimensional isotropic transformation media

    International Nuclear Information System (INIS)

    García-Meca, C; Martí, J; Martínez, A; Ortuño, R

    2014-01-01

    We present a method that enables the implementation of full three-dimensional (3D) transformation media with minimized anisotropy. It is based on a special kind of shape-preserving mapping and a subsequent optimization process. For sufficiently smooth transformations, the resulting anisotropy can be neglected, paving the way for practically realizable 3D devices. The method is independent of the considered wave phenomenon and can thus be applied to any field for which a transformational technique exists, such as acoustics or thermodynamics. Full 3D isotropy has an additional important implication for optical transformation media, as it eliminates the need for magnetic materials in many situations. To illustrate the potential of the method, we design 3D counterparts of transformation-based electromagnetic squeezers and bends. (paper)

  13. The Three-Dimensional EIT Wave

    Science.gov (United States)

    Thompson, B. J.; Biesecker, D. A.; Gilbert, H. R.; Lawrence, G. R.; Ofman, L.; Wu, S. T.; Warmuth, A.; Fisher, Richard R. (Technical Monitor)

    2002-01-01

    An EIT wave is an impulsive disturbance which has been observed in the EUV, Soft X-ray and white light corona, with corresponding observations in the chromosphere. The effects of these disturbances can be observed across the entire solar disk of the Sun, and throughout the inner heliosphere as well. However, the picture is not complete; observations alone do not establish a complete understanding of the nature of this three-dimensional phenomenon. A number of associated phenomena have been documented, though in most cases causality has not determined. Additionally, it is unclear which factors govern the impulse's ability to affect regions of the corona and heliosphere. We discuss the various observations and the models which provided links between the associated phenomena.

  14. Electron microscopical studies of the common bile duct in reindeer

    Directory of Open Access Journals (Sweden)

    Timo Rahko

    1990-08-01

    Full Text Available In a previous publication the authors have described some ultrastructural characteristics of granulated cells in the common bile duct of the reindeer. On the basis of the same material, electron microscopic observations on other tissue elements of bile duct wall are now reported. The surface and glandular epithelium were composed of tall columnar epithelial cells with villous structures on the luminal surfaces. The parietal cytoplasmic membranes of epithelial cells were equipped with intercellular desmosomes while intraepithelial globule leucocytes did not form any junctional complex with other cells. Apical cytoplasmic areas of superficial epithelial cells showed electron-dense small bodies possibly consisting of mucinous substances. The goblet and deep glandular cells, on the other hand, contained numerous large mucin granules with less electron-dense matrices. It appears that their secretions are more abundant than those in superficial epithelial cells which obviously are absorptive as their main function. The nuclei and other cytoplasmic organelles showed profiles similar to those in epithelial cells generally. The lumen of the bile ducts was usually empty or contained fine-granular or amorphous material. An unusual feature was the presence of parts of globule leucocytes or even almost whole cells occurring freely in ductal secretions.Elektronimikroskooppinen tutkimus yhteisen sappikäytävän rakenteesta porolla.Abstract in Finnish / Yhteenveto: Aikaisemmassa julkaisussa tekijät kuvasivat poron yhteisen sappikäytävän (ductus hepaticus communis seinämän jyväsellisten solujen hienorakennetta. Tässä artikkelissa selostetaan saman aineiston perusteella (6 tervettä teurasporoa elektronimikroskooppisia havaintoja sappikäytäväseinämän muista kudosrakenteista. Sappikäytäväseinämän pinta- ja rauhasepiteeli koostuu korkeista epiteelisoluista. Pinnallisia epiteelisoluja kattavat säännölliset mikrovillukset, ja niillä on vain v

  15. Complex composition film condensation in the sluice device of an electron microscope

    International Nuclear Information System (INIS)

    Kukuev, V.I.; Lesovoj, M.V.; Vlasov, D.A.; Malygin, M.V.; Domashevskaya, Eh.P.; Tomashpol'skij, Yu.Ya.

    1994-01-01

    Based on the sluice device of an electron microscope a system is developed for material laser evaporation and vapor condensation on a substrate, situated in the microscope specimen holder. Substrate heating by laser radiation to 100 deg C is used. The system is applied for investigating growth of high-temperature superconductor films

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

    DEFF Research Database (Denmark)

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

    2014-01-01

    The oxidation of nickel particles was studied in situ in an environmental transmission electron microscope in 3.2 mbar of O2 between ambient temperature and 600°C. Several different transmission electron microscopy imaging techniques, electron diffraction and electron energy-loss spectroscopy were...... diffusion of Ni2+ along NiO grain boundaries, self-diffusion of Ni2+ ions and vacancies, growth of NiO grains and nucleation of voids at Ni/NiO interfaces. We also observed the formation of transverse cracks in a growing NiO film in situ in the electron microscope....

  17. Differential ultrahigh-vacuum pump for electron microscope

    International Nuclear Information System (INIS)

    Kroshkov, A.A.; Aseev, A.L.; Baranova, E.A.; Latyshev, A.V.; Yakushenko, O.A.

    1985-01-01

    A differential cryogenic pump for the JEM-7A microscope is described. It reduces the vacuum pressure in the region of the specimen. The device allows tilting and movement of the specimen, direct electrical heating, measurement of specimen temperature, and deposition of films of various substances on the specimen surface. A diagram of the pump shows its placement in the objective chamber of the microscope. The fittings are equipped with bellows and provide for input and output of liquid nitrogen or liquid-helium vapor coolants. The enumerated results attest to a reduction of residual atmospheric pressure in the area of the specimen and the possibility of producing a pure silicon surface in the described device

  18. Evolutionary developments in x ray and electron energy loss microanalysis instrumentation for the analytical electron microscope

    Science.gov (United States)

    Zaluzec, Nester J.

    Developments in instrumentation for both X ray Dispersive and Electron Energy Loss Spectroscopy (XEDS/EELS) over the last ten years have given the experimentalist a greatly enhanced set of analytical tools for characterization. Microanalysts have waited for nearly two decades now in the hope of getting a true analytical microscope and the development of 300 to 400 kV instruments should have allowed us to attain this goal. Unfortunately, this has not generally been the case. While there have been some major improvements in the techniques, there has also been some devolution in the modern AEM (Analytical Electron Microscope). In XEDS, the majority of today's instruments are still plagued by the hole count effect, which was first described in detail over fifteen years ago. The magnitude of this problem can still reach the 20 percent level for medium atomic number species in a conventional off-the-shelf intermediate voltage AEM. This is an absurd situation and the manufacturers should be severely criticized. Part of the blame, however, also rests on the AEM community for not having come up with a universally agreed upon standard test procedure. Fortunately, such a test procedure is in the early stages of refinement. The proposed test specimen consists of an evaporated Cr film approx. 500 to 1000A thick supported upon a 3mm diameter Molybdenum 200 micron aperture.

  19. Integrated three-dimensional display of MR, CT, and PET images of the brain

    International Nuclear Information System (INIS)

    Levin, D.N.; Herrmann, A.; Chen, G.T.Y.

    1988-01-01

    MR, CT, and PET studies depict complementary aspects of brain anatomy and function. The authors' own image-processing software and a Pixar image computer were used to create three-dimensional models of brain soft tissues from MR images, of the skull and calcifications from CT scans, and of brain metabolism from PET images. An image correlation program, based on surface fitting, was used for retrospective registration and merging of these three-dimensional models. The results are demonstrated in a video clip showing how the operator may rotate and perform electronic surgery on the integrated, multimodality three-dimensional model of each patient's brain

  20. Energy-weighted dynamical scattering simulations of electron diffraction modalities in the scanning electron microscope.

    Science.gov (United States)

    Pascal, Elena; Singh, Saransh; Callahan, Patrick G; Hourahine, Ben; Trager-Cowan, Carol; Graef, Marc De

    2018-04-01

    Transmission Kikuchi diffraction (TKD) has been gaining momentum as a high resolution alternative to electron back-scattered diffraction (EBSD), adding to the existing electron diffraction modalities in the scanning electron microscope (SEM). The image simulation of any of these measurement techniques requires an energy dependent diffraction model for which, in turn, knowledge of electron energies and diffraction distances distributions is required. We identify the sample-detector geometry and the effect of inelastic events on the diffracting electron beam as the important factors to be considered when predicting these distributions. However, tractable models taking into account inelastic scattering explicitly are lacking. In this study, we expand the Monte Carlo (MC) energy-weighting dynamical simulations models used for EBSD [1] and ECP [2] to the TKD case. We show that the foil thickness in TKD can be used as a means of energy filtering and compare band sharpness in the different modalities. The current model is shown to correctly predict TKD patterns and, through the dictionary indexing approach, to produce higher quality indexed TKD maps than conventional Hough transform approach, especially close to grain boundaries. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  1. Correlation between mechanical vibrations and resolving power of an electron microscope

    International Nuclear Information System (INIS)

    Lopez, J.J.

    1975-01-01

    The mechanical vibrations of the Grenoble 1MV electron microscope are analyzed. The solutions used to obtain a stability in the order of 3.10 -6 are exposed. A resolution of 1,8A should be achieved [fr

  2. Use of high voltage electron microscope to simulate radiation damage by neutrons

    International Nuclear Information System (INIS)

    Mayer, R.M.

    1976-01-01

    The use of the high voltage electron microscope to simulate radiation damage by neutrons is briefly reviewed. This information is important in explaining how alloying affects void formation during neutron irradiation

  3. Three-dimensional (3D) analysis of the temporomandibular joint

    DEFF Research Database (Denmark)

    Kitai, N.; Kreiborg, S.; Murakami, S.

    Symposium Orthodontics 2001: Where are We Now? Where are We Going?, three-dimensional analysis, temporomandibular joint......Symposium Orthodontics 2001: Where are We Now? Where are We Going?, three-dimensional analysis, temporomandibular joint...

  4. Field emission from individual multiwalled carbon nanotubes prepared in an electron microscope

    NARCIS (Netherlands)

    de Jonge, N.; van Druten, N.J.

    2003-01-01

    Individual multiwalled carbon nanotube field emitters were prepared in a scanning electron microscope. The angular current density, energy spectra, and the emission stability of the field-emitted electrons were measured. An estimate of the electron source brightness was extracted from the

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

    International Nuclear Information System (INIS)

    Gronsky, R.; Thomas, G.

    1983-01-01

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

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

    International Nuclear Information System (INIS)

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

    1989-01-01

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

  7. Decontamination of digital image sensors and assessment of electron microscope performance in a BSL-3 containment

    Directory of Open Access Journals (Sweden)

    Michael B. Sherman

    2015-05-01

    Full Text Available A unique biological safety level (BSL-3 cryo-electron microscopy facility with a 200 keV high-end cryo-electron microscope has been commissioned at the University of Texas Medical Branch (UTMB to study the structure of viruses and bacteria classified as select agents. We developed a microscope decontamination protocol based on chlorine dioxide gas with a continuous flow system. In this paper we report on testing digital camera sensors (both CCD and CMOS direct detector in a BSL-3 environment, and microscope performance after chlorine dioxide (ClO2 decontamination cycles.

  8. Scanning electron microscope - some aspects of the instrument and its applications

    International Nuclear Information System (INIS)

    Thatte, M.R.

    1976-01-01

    Development of the science of microscopy leading to three different types of microscopes - the optical, the conventional transmission electron microscope (CTEM) and the scanning electron microscope(SEM) has been discussed. Special advantages of the SEM in the solution of problems in industrial laboratories are mentioned. A brief reference to the latest instruments announced by Siemens AG shows the modern trends in the technique. A close similarity in image building between SEM and television is indicated. Operational anatomy of the SEM is reviewed. (author)

  9. Atmospheric scanning electron microscope observes cells and tissues in open medium through silicon nitride film.

    Science.gov (United States)

    Nishiyama, Hidetoshi; Suga, Mitsuo; Ogura, Toshihiko; Maruyama, Yuusuke; Koizumi, Mitsuru; Mio, Kazuhiro; Kitamura, Shinichi; Sato, Chikara

    2010-03-01

    Direct observation of subcellular structures and their characterization is essential for understanding their physiological functions. To observe them in open environment, we have developed an inverted scanning electron microscope with a detachable, open-culture dish, capable of 8 nm resolution, and combined with a fluorescence microscope quasi-simultaneously observing the same area from the top. For scanning electron microscopy from the bottom, a silicon nitride film window in the base of the dish maintains a vacuum between electron gun and open sample dish while allowing electrons to pass through. Electrons are backscattered from the sample and captured by a detector under the dish. Cells cultured on the open dish can be externally manipulated under optical microscopy, fixed, and observed using scanning electron microscopy. Once fine structures have been revealed by scanning electron microscopy, their component proteins may be identified by comparison with separately prepared fluorescence-labeled optical microscopic images of the candidate proteins, with their heavy-metal-labeled or stained ASEM images. Furthermore, cell nuclei in a tissue block stained with platinum-blue were successfully observed without thin-sectioning, which suggests the applicability of this inverted scanning electron microscope to cancer diagnosis. This microscope visualizes mesoscopic-scale structures, and is also applicable to non-bioscience fields including polymer chemistry. (c) 2010 Elsevier Inc. All rights reserved.

  10. Study on three dimensional seismic isolation system

    International Nuclear Information System (INIS)

    Morishita, Masaki; Kitamura, Seiji

    2003-01-01

    Japan Nuclear Cycle Development Institute (JNC) and Japan Atomic Power Company (JAPC) launched joint research programs on structural design and three-dimensional seismic isolation technologies, as part of the supporting R and D activities for the feasibility studies on commercialized fast breeder reactor cycle systems. A research project by JAPC under the auspices of the Ministry of Economy, Trade, and Industry (METI) with technical support by JNC is included in this joint study. This report contains the results of the research on the three-dimensional seismic isolation technologies, and the results of this year's study are summarized in the following five aspects. (1) Study on Earthquake Condition for Developing 3-dimensional Base Isolation System. The case study S2 is one of the maximum ground motions, of which the records were investigated up to this time. But a few observed near the fault exceed the case study S2 in the long period domain, depending on the fault length and conditions. Generally it is appropriate that the response spectra ratio (vertical/horizontal) is 0.6. (2) Performance Requirement for 3-dimensional Base Isolation System and Devices. Although the integrity map of main equipment/piping dominate the design criteria for the 3-dimensional base isolation system, the combined integrity map is the same as those of FY 2000, which are under fv=1Hz and over hv=20%. (3) Developing Targets and Schedule for 3-dimensional Isolation Technology. The target items for 3-dimensional base isolation system were rearranged into a table, and developing items to be examined concerning the device were also adjusted. A development plan until FY 2009 was made from the viewpoint of realization and establishment of a design guideline on 3-dimensional base isolation system. (4) Study on 3-dimensional Entire Building Base Isolation System. Three ideas among six ideas that had been proposed in FY2001, i.e., '3-dimensional base isolation system incorporating hydraulic

  11. Construction of a four tip scanning tunneling microscope/scanning electron microscope combination and conductivity measurements of silicide nanowires

    International Nuclear Information System (INIS)

    Zubkov, Evgeniy

    2013-01-01

    In this work the combination of a four-tip scanning tunneling microscope with a scanning electron microscope is presented. By means of this apparatus it is possible to perform the conductivity measurements on the in-situ prepared nanostructures in ultra-high vacuum. With the aid of a scanning electron microscope (SEM), it becomes possible to position the tunneling tips of the four-tip scanning tunneling microscope (STM), so that an arrangement for a four-point probe measurement on nanostructures can be obtained. The STM head was built according to the novel coaxial Beetle concept. This concept allows on the one hand, a very compact arrangement of the components of the STM and on the other hand, the new-built STM head has a good mechanical stability, in order to achieve atomic resolution with all four STM units. The atomic resolution of the STM units was confirmed by scanning a Si(111)-7 x 7 surface. The thermal drift during the STM operation, as well as the resonant frequencies of the mechanical structure of the STM head, were determined. The scanning electron microscope allows the precise and safe navigation of the tunneling tips on the sample surface. Multi tip spectroscopy with up to four STM units can be performed synchronously. To demonstrate the capabilities of the new-built apparatus the conductivity measurements were carried out on metallic yttrium silicide nanowires. The nanowires were prepared by the in-situ deposition of yttrium on a heated Si(110) sample surface. Current-voltage curves were recorded on the nanowires and on the wetting layer in-between. The curves indicate an existence of the Schottky barrier between the yttrium silicide nanowires and the silicon bulk. By means of the two-tip measurements with a gate, the insulating property of the Schottky barrier has been confirmed. Using this Schottky barrier, it is possible to limit the current to the nanowire and to prevent it from flowing through the silicon bulk. A four-tip resistance measurement

  12. Comparison of Electron Imaging Modes for Dimensional Measurements in the Scanning Electron Microscope.

    Science.gov (United States)

    Postek, Michael T; Vladár, András E; Villarrubia, John S; Muto, Atsushi

    2016-08-01

    Dimensional measurements from secondary electron (SE) images were compared with those from backscattered electron (BSE) and low-loss electron (LLE) images. With the commonly used 50% threshold criterion, the lines consistently appeared larger in the SE images. As the images were acquired simultaneously by an instrument with the capability to operate detectors for both signals at the same time, the differences cannot be explained by the assumption that contamination or drift between images affected the SE, BSE, or LLE images differently. Simulations with JMONSEL, an electron microscope simulator, indicate that the nanometer-scale differences observed on this sample can be explained by the different convolution effects of a beam with finite size on signals with different symmetry (the SE signal's characteristic peak versus the BSE or LLE signal's characteristic step). This effect is too small to explain the >100 nm discrepancies that were observed in earlier work on different samples. Additional modeling indicates that those discrepancies can be explained by the much larger sidewall angles of the earlier samples, coupled with the different response of SE versus BSE/LLE profiles to such wall angles.

  13. Path-separated electron interferometry in a scanning transmission electron microscope

    Science.gov (United States)

    Yasin, Fehmi S.; Harvey, Tyler R.; Chess, Jordan J.; Pierce, Jordan S.; McMorran, Benjamin J.

    2018-05-01

    We report a path-separated electron interferometer within a scanning transmission electron microscope. In this setup, we use a nanofabricated grating as an amplitude-division beamsplitter to prepare multiple spatially separated, coherent electron probe beams. We achieve path separations of 30 nm. We pass the  +1 diffraction order probe through amorphous carbon while passing the 0th and  ‑1 orders through vacuum. The probes are then made to interfere via imaging optics, and we observe an interference pattern at the CCD detector with up to 39.7% fringe visibility. We show preliminary experimental results in which the interference pattern was recorded during a 1D scan of the diffracted probes across a test phase object. These results qualitatively agree with a modeled interference predicted by an independent measurement of the specimen thickness. This experimental design can potentially be applied to phase contrast imaging and fundamental physics experiments, such as an exploration of electron wave packet coherence length.

  14. The Reaction Microscope: Imaging and Pulse Shaping Control in Photodynamics

    NARCIS (Netherlands)

    Vredenborg, A.; Lehmann, C.S.; Irimia, D.; Roeterdink, W.; Janssen, M.H.M.

    2011-01-01

    Herein, we review the current capabilities and potential of advanced single-particle imaging techniques to study photodynamics in isolated molecules. These reaction microscopes are able to measure the full three-dimensional energy and angular distribution of (correlated) particles such as electrons

  15. Light and electron microscope assessment of the lytic activity of ...

    African Journals Online (AJOL)

    The Microcystis cells were exposed to copper, B. mycoides B16 and Triton X-100, in order to ascertain the level of cell membrane damage. The membrane cell damage ... The electron microscopy observations appeared to reveal at least two mechanisms of Microcystis lysis (contact and parasitism). The light and electron ...

  16. A new program for the design of electron microscopes

    Czech Academy of Sciences Publication Activity Database

    Lencová, Bohumila; Zlámal, J.

    2008-01-01

    Roč. 1, č. 1 (2008), s. 315-324 ISSN 1875-3892. [International Conference on Charged Particle Optics /7./ CPO-7. Cambridge, 24.07.2006-28.07.2006] Institutional research plan: CEZ:AV0Z20650511 Keywords : finite element method * electron lenses and deflectors * computer-aided design * user interface Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  17. An Electron Microscope Study of the Yeast Pityrosporum ovale

    NARCIS (Netherlands)

    Kreger-van Rij, N.J.W.; Veenhuis, M.

    1970-01-01

    Cells of Pityrosporum ovale were prepared for electron microscopy by different methods of fixation and embedding, all of them causing some degree of damage to the cells. Apart from the usual organelles seen in other yeast cells, a body was found which showed an electron-dense outer layer and an

  18. Note: A scanning electron microscope sample holder for bidirectional characterization of atomic force microscope probe tips

    Energy Technology Data Exchange (ETDEWEB)

    Eisenstein, Alon; Goh, M. Cynthia [Department of Chemistry and Institute for Optical Sciences, University of Toronto, 80 St. George Street, Toronto M5S 3H6 (Canada)

    2012-03-15

    A novel sample holder that enables atomic force microscopy (AFM) tips to be mounted inside a scanning electron microscopy (SEM) for the purpose of characterizing the AFM tips is described. The holder provides quick and easy handling of tips by using a spring clip to hold them in place. The holder can accommodate two tips simultaneously in two perpendicular orientations, allowing both top and side view imaging of the tips by the SEM.

  19. Three dimensional imaging of surface geometry in SEM

    International Nuclear Information System (INIS)

    Slowko, W.

    1997-01-01

    A great advantage of scanning electron microscopy (SEM) is its ability of the surface topography in the way as a human eye is accustomed to see lights and shadows on macroobjects. However, SEM's can hardly display vertical dimensions of the structures. One of possible solutions is reconstruction of the surface profiles by directional detection of secondary electrons and proper signal processing. However, the surface profile still gives two dimensional information and the method should be extended to obtain fully three dimensional imaging. The extension consists in a simultaneous reconstruction of the surface profiles in two perpendicular directions (x and y) and their superposition. The solution proposed is based on a quadrupole detector system and a computer or analogue system for signal processing. Quantitative data of the surface topography can be displayed in many manners in the system of two or three co-ordinates with use of pseudo-colour for the altitude coding. (author)

  20. Three-dimensional imaging of atomic four-body processes

    CERN Document Server

    Schulz, M; Fischer, D; Kollmus, H; Madison, D H; Jones, S; Ullrich, J

    2003-01-01

    To understand the physical processes that occur in nature we need to obtain a solid concept about the 'fundamental' forces acting between pairs of elementary particles. it is also necessary to describe the temporal and spatial evolution of many mutually interacting particles under the influence of these forces. This latter step, known as the few-body problem, remains an important unsolved problem in physics. Experiments involving atomic collisions represent a useful testing ground for studying the few-body problem. For the single ionization of a helium atom by charged particle impact, kinematically complete experiments have been performed since 1969. The theoretical analysis of such experiments was thought to yield a complete picture of the basic features of the collision process, at least for large collision energies. These conclusions are, however, almost exclusively based on studies of restricted electron-emission geometries. We report three- dimensional images of the complete electron emission pattern for...

  1. Clinical significance of three-dimensional sonohysterography

    International Nuclear Information System (INIS)

    Lee, Eun Hye; Lee, Mi Hwa; Lee, Chan; Kim, Jong Wook; Shin, Myung Choel

    1999-01-01

    To evaluate the usefulness of three dimensional sonohysterography (3D SHG) in the evaluation of uterine endometrial and submucosal lesions in comparison with conventional two-dimensional sonohysterography (2D SHG). Our series consisted of 26 patients (mean aged 41 years) who complained of uterine bleeding, menorrhagia, or dysmenorrhea. 2D SHG was performed, and then 3D SHG was done after the volume mode was switched on. Simultaneous display of three perpendicular two-dimensional planes and surface rendering of findings on particular section were obtained. We analyzed whether the endometrium was thickened or not, and the location, size, shape, echogenicity, posterior shadowing, and echogenic rim of the focal lesion. The results were compared with the pathologic findings or MRI. There were submucosal myomas (n=12), intramural myomas (n=2), endometrial polyps (n=7), placental polyp (n=1), and normal endometrial cavities (n=4) on SHG. Nineteen cases were confirmed by pathologic findings or MRI. The results were correlated in 89% (17/19) of the cases. We misdiagnosed 2 cases: focal endometrial hyperplasia and choriocarcinoma were misdiagnosed as endometrial polyp and placental polyp, respectively. Imaging diagnoses were same in the techniques. Comparing with 2D SHG, 3D SHG provided a subjective display of pathologic findings and an additional information about spatial relationship between focal lesion and surroundings.

  2. Clinical significance of three-dimensional sonohysterography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Hye; Lee, Mi Hwa; Lee, Chan; Kim, Jong Wook; Shin, Myung Choel [Pochon Cha University College of Medicine, Pochon (Korea, Republic of)

    1999-12-15

    To evaluate the usefulness of three dimensional sonohysterography (3D SHG) in the evaluation of uterine endometrial and submucosal lesions in comparison with conventional two-dimensional sonohysterography (2D SHG). Our series consisted of 26 patients (mean aged 41 years) who complained of uterine bleeding, menorrhagia, or dysmenorrhea. 2D SHG was performed, and then 3D SHG was done after the volume mode was switched on. Simultaneous display of three perpendicular two-dimensional planes and surface rendering of findings on particular section were obtained. We analyzed whether the endometrium was thickened or not, and the location, size, shape, echogenicity, posterior shadowing, and echogenic rim of the focal lesion. The results were compared with the pathologic findings or MRI. There were submucosal myomas (n=12), intramural myomas (n=2), endometrial polyps (n=7), placental polyp (n=1), and normal endometrial cavities (n=4) on SHG. Nineteen cases were confirmed by pathologic findings or MRI. The results were correlated in 89% (17/19) of the cases. We misdiagnosed 2 cases: focal endometrial hyperplasia and choriocarcinoma were misdiagnosed as endometrial polyp and placental polyp, respectively. Imaging diagnoses were same in the techniques. Comparing with 2D SHG, 3D SHG provided a subjective display of pathologic findings and an additional information about spatial relationship between focal lesion and surroundings.

  3. Bifurcation analysis of a three dimensional system

    Directory of Open Access Journals (Sweden)

    Yongwen WANG

    2018-04-01

    Full Text Available In order to enrich the stability and bifurcation theory of the three dimensional chaotic systems, taking a quadratic truncate unfolding system with the triple singularity equilibrium as the research subject, the existence of the equilibrium, the stability and the bifurcation of the system near the equilibrium under different parametric conditions are studied. Using the method of mathematical analysis, the existence of the real roots of the corresponding characteristic equation under the different parametric conditions is analyzed, and the local manifolds of the equilibrium are gotten, then the possible bifurcations are guessed. The parametric conditions under which the equilibrium is saddle-focus are analyzed carefully by the Cardan formula. Moreover, the conditions of codimension-one Hopf bifucation and the prerequisites of the supercritical and subcritical Hopf bifurcation are found by computation. The results show that the system has abundant stability and bifurcation, and can also supply theorical support for the proof of the existence of the homoclinic or heteroclinic loop connecting saddle-focus and the Silnikov's chaos. This method can be extended to study the other higher nonlinear systems.

  4. Three-dimensional dynamics of protostellar evolution

    International Nuclear Information System (INIS)

    Cook, T.L.

    1977-06-01

    A three-dimensional finite difference numerical methodology was developed for self-gravitating, rotating gaseous systems. The fully nonlinear equations for time-varying fluid dynamics are solved by high speed computer in a cylindrical coordinate system rotating with an instantaneous angular velocity, selected such that the net angular momentum relative to the rotating frame is zero. The time-dependent adiabatic collapse of gravitationally bound, rotating, protostellar clouds is studied for specified uniform and nonuniform initial conditions. Uniform clouds can form axisymmetric, rotating toroidal configurations. If the thermal pressure is high, nonuniform clouds can also collapse to axisymmetric toroids. For low thermal pressures, however, the collapsing cloud is unstable to initial perturbations. The fragmentation of protostellar clouds is investigated by studying the response of rotating, self-gravitating, equilibrium toroids to non-axisymmetric perturbations. The detailed evolution of the fragmenting toroid depends upon a non-dimensional function of the initial entropy, the total mass in the toroid, the angular velocity of rotation, and the number of perturbation wavelengths around the circumference of the toroid. For low and intermediate entropies, the configuration develops into co-rotating components with spiral streamers. In the spiral regions retrograde vortices are observed in some examples. For high levels of entropy, barred spirals can exist as intermediate states of the fragmentation

  5. Three-dimensional dynamics of protostellar evolution

    International Nuclear Information System (INIS)

    Cook, T.L.; Harlow, F.H.

    1978-01-01

    A three-dimensional finite difference numerical methodology has been developed for self-gravitating, rotating gaseous systems. The fully nonlinear equations for time-varying fluid dynamics are solved by high-speed computer in a cylindrical coordinate system rotating with an instantaneous angular velocity. The time-dependent adiabatic collapse of gravitationally bound, rotating, protostellar clouds is studied for specified uniform and nonuniform initial conditions. Uniform clouds can form axisymmetric, rotating toroidal configurations. If the thermal pressure is high, nonuniform clouds can also collapse to axisymmetric ellipsoids. For low thermal pressures, however, the collapsing cloud is unstable to perturbations. The resulting fragmentation of unstable protostellar clouds is investigated by studying the response of rotating, self-gravitating, equilibrium toroids to nonaxisymmetric perturbations. The detailed evolution of the fragmentation toroid depends upon a nondimensional function of the initial entropy, the total mass in the toroid, the angular velocity of rotation, and the number of perturbation wave-lengths around the circumference of the toroid. For low and intermediate entropies, the configuration develops into corotating components with spiral streamers. In the spiral regions retrograde vortices are observed in some examples. For high levels of entropy, barred spirals can exist as intermediate states of the fragmentation

  6. Three dimensional characterization and archiving system

    International Nuclear Information System (INIS)

    Sebastian, R.L.; Clark, R.; Gallman, P.

    1995-01-01

    The Three Dimensional Characterization and Archiving System (3D-ICAS) is being developed as a remote system to perform rapid in situ analysis of hazardous organics and radionuclide contamination on structural materials. Coleman Research and its subcontractors, Thermedics Detection, Inc. (TD) and the University of Idaho (UI) are in the second phase of a three phase program to develop 3D-ICAS to support Decontamination and Decommissioning (D ampersand D) operations. Accurate physical characterization of surfaces and the radioactive and organic is a critical D ampersand D task. Surface characterization includes identification of potentially dangerous inorganic materials, such as asbestos and transite. Real-time remotely operable characterization instrumentation will significantly advance the analysis capabilities beyond those currently employed. Chemical analysis is a primary area where the characterization process will be improved. Chemical analysis plays a vital role throughout the process of decontamination. Before clean-up operations can begin the site must be characterized with respect to the type and concentration of contaminants, and detailed site mapping must clarify areas of both high and low risk. During remediation activities chemical analysis provides a means to measure progress and to adjust clean-up strategy. Once the clean-up process has been completed the results of chemical analysis will verify that the site is in compliance with federal and local regulations

  7. MORPHOLOGICAL DESCRIPTIONS USING THREE-DIMENSIONAL WAVEFRONTS

    Directory of Open Access Journals (Sweden)

    Jean Serra

    2011-05-01

    Full Text Available The present study deals with the analysis of three-dimensional binary objects whose structure is not obvious nor generally clearly visible. Our approach is illustrated through three examples taken from biological microscopy. In one of our examples, we need to extract the osteocytes contained in sixty confocal sections. The cells are not numerous, but are characterized by long branches, hence they will be separated using a directional wavefront The two other objects are more complex and will be analysed by means of a spherical wavefront In the first case, a kidney of a rat embryo, the tissue grows like a tree, where we want to detect the branches, their extremities,and their spatial arrangement. The wavefront method enables us to define precisely branches and extremities, and gives flexible algorithms. The last example deals with the embryonic growth of the chicken shinbone. The central part of the bone (or shaft is structured as a series of nested cylinders following the same axis, and connected by more or less long bridges. Using wavefronts, we show that it is possible to separate the cylinders,and to extract and count the bridges that connect them.

  8. Three dimensional image alignment, registration and fusion

    International Nuclear Information System (INIS)

    Treves, S.T.; Mitchell, K.D.; Habboush, I.H.

    1998-01-01

    Combined assessment of three dimensional anatomical and functional images (SPECT, PET, MRI, CT) is useful to determine the nature and extent of lesions in many parts of the body. Physicians principally rely on their spatial sense of mentally re-orient and overlap images obtained with different imaging modalities. Objective methods that enable easy and intuitive image registration can help the physician arrive at more optimal diagnoses and better treatment decisions. This review describes a simple, intuitive and robust image registration approach developed in our laboratory. It differs from most other registration techniques in that it allows the user to incorporate all of the available information within the images in the registration process. This method takes full advantage of the ability of knowledgeable operators to achieve image registration and fusion using an intuitive interactive visual approach. It can register images accurately and quickly without the use of elaborate mathematical modeling or optimization techniques. The method provides the operator with tools to manipulate images in three dimensions, including visual feedback techniques to assess the accuracy of registration (grids, overlays, masks, and fusion of images in different colors). Its application is not limited to brain imaging and can be applied to images from any region in the body. The overall effect is a registration algorithm that is easy to implement and can achieve accuracy on the order of one pixel

  9. Three-Dimensional Printed Thermal Regulation Textiles.

    Science.gov (United States)

    Gao, Tingting; Yang, Zhi; Chen, Chaoji; Li, Yiju; Fu, Kun; Dai, Jiaqi; Hitz, Emily M; Xie, Hua; Liu, Boyang; Song, Jianwei; Yang, Bao; Hu, Liangbing

    2017-11-28

    Space cooling is a predominant part of energy consumption in people's daily life. Although cooling the whole building is an effective way to provide personal comfort in hot weather, it is energy-consuming and high-cost. Personal cooling technology, being able to provide personal thermal comfort by directing local heat to the thermally regulated environment, has been regarded as one of the most promising technologies for cooling energy and cost savings. Here, we demonstrate a personal thermal regulated textile using thermally conductive and highly aligned boron nitride (BN)/poly(vinyl alcohol) (PVA) composite (denoted as a-BN/PVA) fibers to improve the thermal transport properties of textiles for personal cooling. The a-BN/PVA composite fibers are fabricated through a fast and scalable three-dimensional (3D) printing method. Uniform dispersion and high alignment of BN nanosheets (BNNSs) can be achieved during the processing of fiber fabrication, leading to a combination of high mechanical strength (355 MPa) and favorable heat dispersion. Due to the improved thermal transport property imparted by the thermally conductive and highly aligned BNNSs, better cooling effect (55% improvement over the commercial cotton fiber) can be realized in the a-BN/PVA textile. The wearable a-BN/PVA textiles containing the 3D-printed a-BN/PVA fibers offer a promising selection for meeting the personal cooling requirement, which can significantly reduce the energy consumption and cost for cooling the whole building.

  10. Three-dimensional printing for craniomaxillofacial regeneration.

    Science.gov (United States)

    Gaviria, Laura; Pearson, Joseph J; Montelongo, Sergio A; Guda, Teja; Ong, Joo L

    2017-10-01

    Craniomaxillofacial injuries produce complex wound environments involving various tissue types and treatment strategies. In a clinical setting, care is taken to properly irrigate and stabilize the injury, while grafts are molded in an attempt to maintain physiological functionality and cosmesis. This often requires multiple surgeries and grafts leading to added discomfort, pain and financial burden. Many of these injuries can lead to disfigurement and resultant loss of system function including mastication, respiration, and articulation, and these can lead to acute and long-term psychological impact on the patient. A main causality of these issues is the lack of an ability to spatially control pre-injury morphology while maintaining shape and function. With the advent of additive manufacturing (three-dimensional printing) and its use in conjunction with biomaterial regenerative strategies and stem cell research, there is an increased potential capacity to alleviate such limitations. This review focuses on the current capabilities of additive manufacturing platforms, completed research and potential for future uses in the treatment of craniomaxillofacial injuries, with an in-depth discussion of regeneration of the periodontal complex and teeth.

  11. Three-dimensional supersonic vortex breakdown

    Science.gov (United States)

    Kandil, Osama A.; Kandil, Hamdy A.; Liu, C. H.

    1993-01-01

    Three-dimensional supersonic vortex-breakdown problems in bound and unbound domains are solved. The solutions are obtained using the time-accurate integration of the unsteady, compressible, full Navier-Stokes (NS) equations. The computational scheme is an implicit, upwind, flux-difference splitting, finite-volume scheme. Two vortex-breakdown applications are considered in the present paper. The first is for a supersonic swirling jet which is issued from a nozzle into a supersonic uniform flow at a lower Mach number than that of the swirling jet. The second is for a supersonic swirling flow in a configured circular duct. In the first application, an extensive study of the effects of grid fineness, shape and grid-point distribution on the vortex breakdown is presented. Four grids are used in this study and they show a substantial dependence of the breakdown bubble and shock wave on the grid used. In the second application, the bubble-type and helix-type vortex breakdown have been captured.

  12. Three-dimensional laparoscopy: Principles and practice

    Directory of Open Access Journals (Sweden)

    Rakesh Y Sinha

    2017-01-01

    Full Text Available The largest challenge for laparoscopic surgeons is the eye–hand coordination within a three-dimensional (3D scene observed on a 2D display. The 2D view on flat screen laparoscopy is cerebrally intensive. The loss of binocular vision on a 2D display causes visual misperceptions, mainly loss of depth perception and adds to the surgeon's fatigue. This compromises the safety of laparoscopy. The 3D high-definition view with great depth perception and tactile feedback makes laparoscopic surgery more acceptable, safe and cost-effective. It improves surgical precision and hand–eye coordination, conventional and all straight stick instruments can be used, capital expenditure is less and recurring cost and annual maintenance cost are less. In this article, we have discussed the physics of 3D laparoscopy, principles of depth perception, and the different kinds of 3D systems available for laparoscopy. We have also discussed our experience of using 3D laparoscopy in over 2000 surgeries in the last 4 years.

  13. Three dimensional characterization and archiving system

    Energy Technology Data Exchange (ETDEWEB)

    Sebastian, R.L.; Clark, R.; Gallman, P. [Coleman Research Corp., Springfield, VA (United States)] [and others

    1995-10-01

    The Three Dimensional Characterization and Archiving System (3D-ICAS) is being developed as a remote system to perform rapid in situ analysis of hazardous organics and radionuclide contamination on structural materials. Coleman Research and its subcontractors, Thermedics Detection, Inc. (TD) and the University of Idaho (UI) are in the second phase of a three phase program to develop 3D-ICAS to support Decontamination and Decommissioning (D&D) operations. Accurate physical characterization of surfaces and the radioactive and organic is a critical D&D task. Surface characterization includes identification of potentially dangerous inorganic materials, such as asbestos and transite. The 3D-ICAS system robotically conveys a multisensor probe near the surface to be inspected. The sensor position and orientation are monitored and controlled by Coherent laser radar (CLR) tracking. The ICAS fills the need for high speed automated organic analysis by means of gas chromatography-mass spectrometry sensors, and also by radionuclide sensors which combines alpha, beta, and gamma counting.

  14. Three dimensional characterization and archiving system

    International Nuclear Information System (INIS)

    Sebastian, R.L.; Clark, R.; Gallman, P.

    1996-01-01

    The Three Dimensional Characterization and Archiving System (3D-ICAS) is being developed as a remote system to perform rapid in situ analysis of hazardous organics and radionuclide contamination on structural materials. Coleman Research and its subcontractors, Thermedics Detection, Inc. (TD) and the University of Idaho (UI) are in the second phase of a three phase program to develop 3D-ICAS to support Decontamination and Decommissioning (D and D) operations. Accurate physical characterization of surfaces and the radioactive and organic is a critical D and D task. Surface characterization includes identification of potentially dangerous inorganic materials, such as asbestos and transite. Real-time remotely operable characterization instrumentation will significantly advance the analysis capabilities beyond those currently employed. Chemical analysis is a primary area where the characterization process will be improved. The 3D-ICAS system robotically conveys a multisensor probe near the surfaces to be inspected. The sensor position and orientation are monitored and controlled using coherent laser radar (CLR) tracking. The CLR also provides 3D facility maps which establish a 3D world view within which the robotic sensor system can operate

  15. Three-dimensional RAMA fluence methodology benchmarking

    International Nuclear Information System (INIS)

    Baker, S. P.; Carter, R. G.; Watkins, K. E.; Jones, D. B.

    2004-01-01

    This paper describes the benchmarking of the RAMA Fluence Methodology software, that has been performed in accordance with U. S. Nuclear Regulatory Commission Regulatory Guide 1.190. The RAMA Fluence Methodology has been developed by TransWare Enterprises Inc. through funding provided by the Electric Power Research Inst., Inc. (EPRI) and the Boiling Water Reactor Vessel and Internals Project (BWRVIP). The purpose of the software is to provide an accurate method for calculating neutron fluence in BWR pressure vessels and internal components. The Methodology incorporates a three-dimensional deterministic transport solution with flexible arbitrary geometry representation of reactor system components, previously available only with Monte Carlo solution techniques. Benchmarking was performed on measurements obtained from three standard benchmark problems which include the Pool Criticality Assembly (PCA), VENUS-3, and H. B. Robinson Unit 2 benchmarks, and on flux wire measurements obtained from two BWR nuclear plants. The calculated to measured (C/M) ratios range from 0.93 to 1.04 demonstrating the accuracy of the RAMA Fluence Methodology in predicting neutron flux, fluence, and dosimetry activation. (authors)

  16. Three-Dimensional Printed Graphene Foams.

    Science.gov (United States)

    Sha, Junwei; Li, Yilun; Villegas Salvatierra, Rodrigo; Wang, Tuo; Dong, Pei; Ji, Yongsung; Lee, Seoung-Ki; Zhang, Chenhao; Zhang, Jibo; Smith, Robert H; Ajayan, Pulickel M; Lou, Jun; Zhao, Naiqin; Tour, James M

    2017-07-25

    An automated metal powder three-dimensional (3D) printing method for in situ synthesis of free-standing 3D graphene foams (GFs) was successfully modeled by manually placing a mixture of Ni and sucrose onto a platform and then using a commercial CO 2 laser to convert the Ni/sucrose mixture into 3D GFs. The sucrose acted as the solid carbon source for graphene, and the sintered Ni metal acted as the catalyst and template for graphene growth. This simple and efficient method combines powder metallurgy templating with 3D printing techniques and enables direct in situ 3D printing of GFs with no high-temperature furnace or lengthy growth process required. The 3D printed GFs show high-porosity (∼99.3%), low-density (∼0.015g cm -3 ), high-quality, and multilayered graphene features. The GFs have an electrical conductivity of ∼8.7 S cm -1 , a remarkable storage modulus of ∼11 kPa, and a high damping capacity of ∼0.06. These excellent physical properties of 3D printed GFs indicate potential applications in fields requiring rapid design and manufacturing of 3D carbon materials, for example, energy storage devices, damping materials, and sound absorption.

  17. Scanning three-dimensional x-ray diffraction microscopy using a high-energy microbeam

    International Nuclear Information System (INIS)

    Hayashi, Y.; Hirose, Y.; Seno, Y.

    2016-01-01

    A scanning three-dimensional X-ray diffraction (3DXRD) microscope apparatus with a high-energy microbeam was installed at the BL33XU Toyota beamline at SPring-8. The size of the 50 keV beam focused using Kirkpatrick-Baez mirrors was 1.3 μm wide and 1.6 μm high in full width at half maximum. The scanning 3DXRD method was tested for a cold-rolled carbon steel sheet sample. A three-dimensional orientation map with 37 "3 voxels was obtained.

  18. Scanning three-dimensional x-ray diffraction microscopy using a high-energy microbeam

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Y., E-mail: y-hayashi@mosk.tytlabs.co.jp; Hirose, Y.; Seno, Y. [Toyota Central R& D Toyota Central R& D Labs., Inc., 41-1 Nagakute Aichi 480-1192 Japan (Japan)

    2016-07-27

    A scanning three-dimensional X-ray diffraction (3DXRD) microscope apparatus with a high-energy microbeam was installed at the BL33XU Toyota beamline at SPring-8. The size of the 50 keV beam focused using Kirkpatrick-Baez mirrors was 1.3 μm wide and 1.6 μm high in full width at half maximum. The scanning 3DXRD method was tested for a cold-rolled carbon steel sheet sample. A three-dimensional orientation map with 37 {sup 3} voxels was obtained.

  19. Hartmann characterization of the PEEM-3 aberration-corrected X-ray photoemission electron microscope.

    Science.gov (United States)

    Scholl, A; Marcus, M A; Doran, A; Nasiatka, J R; Young, A T; MacDowell, A A; Streubel, R; Kent, N; Feng, J; Wan, W; Padmore, H A

    2018-05-01

    Aberration correction by an electron mirror dramatically improves the spatial resolution and transmission of photoemission electron microscopes. We will review the performance of the recently installed aberration corrector of the X-ray Photoemission Electron Microscope PEEM-3 and show a large improvement in the efficiency of the electron optics. Hartmann testing is introduced as a quantitative method to measure the geometrical aberrations of a cathode lens electron microscope. We find that aberration correction leads to an order of magnitude reduction of the spherical aberrations, suggesting that a spatial resolution of below 100 nm is possible at 100% transmission of the optics when using x-rays. We demonstrate this improved performance by imaging test patterns employing element and magnetic contrast. Published by Elsevier B.V.

  20. Three-dimensional Majorana fermions in chiral superconductors.

    Science.gov (United States)

    Kozii, Vladyslav; Venderbos, Jörn W F; Fu, Liang

    2016-12-01

    Using a systematic symmetry and topology analysis, we establish that three-dimensional chiral superconductors with strong spin-orbit coupling and odd-parity pairing generically host low-energy nodal quasiparticles that are spin-nondegenerate and realize Majorana fermions in three dimensions. By examining all types of chiral Cooper pairs with total angular momentum J formed by Bloch electrons with angular momentum j in crystals, we obtain a comprehensive classification of gapless Majorana quasiparticles in terms of energy-momentum relation and location on the Fermi surface. We show that the existence of bulk Majorana fermions in the vicinity of spin-selective point nodes is rooted in the nonunitary nature of chiral pairing in spin-orbit-coupled superconductors. We address experimental signatures of Majorana fermions and find that the nuclear magnetic resonance spin relaxation rate is significantly suppressed for nuclear spins polarized along the nodal direction as a consequence of the spin-selective Majorana nature of nodal quasiparticles. Furthermore, Majorana nodes in the bulk have nontrivial topology and imply the presence of Majorana bound states on the surface, which form arcs in momentum space. We conclude by proposing the heavy fermion superconductor PrOs 4 Sb 12 and related materials as promising candidates for nonunitary chiral superconductors hosting three-dimensional Majorana fermions.